Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determin...Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.展开更多
Background:Acinetobacter baumannii(A.baumannii)is known as an opportunistic pathogen related to health-care-associated infection that has a high antibiotic resistance potential,notably against carbapenems that are wid...Background:Acinetobacter baumannii(A.baumannii)is known as an opportunistic pathogen related to health-care-associated infection that has a high antibiotic resistance potential,notably against carbapenems that are widely used to combat A.baumannii infections.This study aimed to detect oxacillin-hydrolyzing(OXA)carbapenemases and metallo-β-lactamases(MBL)among carbapenem-resistant A.baumannii isolated strains and to determine their clonal relationship by repetitive extragenic palindromic PCR(rep-PCR).Methods:In the present study,a total of 211 non-repetitive isolates of A.baumannii were collected from Qazvin educational hospitals(2016–2017).The disk diffusion method was used to investigate the antibiotic susceptibility of studied strains,followed by the detection of MBL and OXA-type genes using polymerase chain reaction(PCR)and sequencing methods.The rep-PCR method assessed the clonal relationship of carbapenem-non-susceptible A.baumannii isolates.Result:The obtained results showed that 87.2%and 86.7%of isolates were non-susceptible to imipenem and meropenem.The blaOXA-24(93.5%)was the most frequent gene,followed by the blaOXA-23(4.34%),blaIMP-1(1.63%),and blaVIM-1(0.54%).Meanwhile,blaOXA-58 and blaOXA-143 genes were not found.81.5%and 66.1%of isolates contained ISAba1 upstream of the blaOXA-23 and blaOXA-58 genes,respectively.Rep-PCR results revealed the carbapenem non-susceptible isolates belonged to three distinct clones:A 171(81%),B 34(16.1%),and C 6(2.8%).Conclusions:The results indicated a high prevalence of carbapenem-non-susceptible A.baumannii,with the emergence of the blaOXA-24 gene as the most common gene and the notable prevalence of MBL genes.These results revealed the need for appropriate therapeutic and infection control strategies and monitoring susceptibility patterns for controlling A.baumannii infections.展开更多
To investigate the distribution of the genes of two major metallo-β-1actamases （MBL;i.e.,IMP and VIM） and class 1 integrons （intI） in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates...To investigate the distribution of the genes of two major metallo-β-1actamases （MBL;i.e.,IMP and VIM） and class 1 integrons （intI） in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for blaIMP-1, blaVIM and blaVIM-2 genes. The MBL-positive isolates were further assessed for class 1 integrons by PCRusing specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the blaVIM gene was found in 81.5% （53/65） of all isolates, blaVIM-2 gene was found in only 1 isolate and the intl gene was observed in 45.3% （24/53） of blaVIM-positive isolates. One isolate carried simultaneously both blaIMP-1 and intl genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM β-1actamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P.aeruginosa.展开更多
Objective:To detect and evaluate the various methods for metallo-β-lactamases(MBL) production in Pseudomonas aeruginosa(P.aeruginosa) and Acinetobacter species.Methods:A total of 109 P.aeruginosa and 85 Acinetobacter...Objective:To detect and evaluate the various methods for metallo-β-lactamases(MBL) production in Pseudomonas aeruginosa(P.aeruginosa) and Acinetobacter species.Methods:A total of 109 P.aeruginosa and 85 Acinetobacter species were screened for imipenem resistance by Kirby- Bauer disc diffusion methods.Detection of MBL production was(lone by imipenem-EDTA combined disc test,double disc synerygy test(DDST) and imipenem-EDTA MBL E test.Results: A total of 63(57.8%) strains of P.aeruginosa and 46(54.1%) strains of Acinetobacter spp.were found to be resistant to imipenem.Of the 63 imipenem resistant P.aeruginosa tested for MBL production.44(69.89;) were found to be positive and among 46 imipenem resistant Acinetobacter. 19(41.3%) were shown to be the MBL producers.Conclusions:Imipenem-EDTA combined disc test and MBL E test are equally effective for MBL detection in both P.aeruginosa and Acinetobacter spp.,but given the cost-constraints,combined disc can be used as a convenient screening method in the clinical microbiology laboratory.展开更多
Antibiotic resistance is one of the most significant challenges facing global healthcare. Since the 1940s, antibiotics have been used to fight infections, initially with penicillin and subsequently with various deriva...Antibiotic resistance is one of the most significant challenges facing global healthcare. Since the 1940s, antibiotics have been used to fight infections, initially with penicillin and subsequently with various derivatives including cephalosporins, carbapenams and monobactams. A common characteristic of these antibiotics is the four-memberedβ-lactam ring. Alarmingly, in recent years an increasing number of bacteria have become resistant to these antibiotics. A major strategy employed by these pathogens is to use Zn(II)-dependent enzymes, the metallo-β-lactamases (MBLs), which hydrolyse theβ-lactam ring. Clinically useful MBL inhibitors are not yet available. Consequently, MBLs remain a major threat to human health. In this review biochemical properties of MBLs are discussed, focusing in particular on the interactions between the enzymes and the functionally essential metal ions. The precise role(s) of these metal ions is still debated and may differ between different MBLs. However, since they are required for catalysis, their binding site may present an alternative target for inhibitor design.展开更多
Pseudomonas aeruginosa is a major cause of nosocomial infections with high mortality rates. The organism is highly resistant to most classes of drugs used and can develop resistance during treatment. One of the resist...Pseudomonas aeruginosa is a major cause of nosocomial infections with high mortality rates. The organism is highly resistant to most classes of drugs used and can develop resistance during treatment. One of the resistance mechanisms of P. aeruginosais is Metallo-β-Lactamase (MBL) production. MBL producing P. aeruginosa is a major health concern given it’s resistance to almost all available drugs. The prevalence of this resistant strain is unknown since there is no standardized method for testing MBL production. This was a laboratory based cross-sectional prospective study that was carried out from September 2015 to March 2016 at Kenyatta National Hospital. Ninety-nine isolates of P. aeruginosa were collected during the period and tested for antimicrobial susceptibility and isolates found to be resistant to imipenem tested for MBL production. The results indicated high resistance of P. aeruginosa to commonly used drugs. Of the isolates tested 69.7% were resistant to piperacillin, 63.6% were resistant to aztreonam, 58.6% were resistant to levofloxacin, 55.6% were resistant to cefipime, 65.7% were resistant to ceftazidime, 68.7% were resistant to ticarcillin-clavulanate, 72.2% were resistant to meropenem, 64.9% were resistance to imipenem while 86.4% of urine isolates were resistant to ofloxacin. Of the isolates resistant to imipenem 87.3% were found to be MBL producers. In conclusion, P. aeruginosais highly resistant to the drugs currently is used for treatment and resistance to carbapenems is largely due to MBL production.展开更多
Antibiotic resistance has emerged as a major global threat to human health. Among the strategies employed by pathogens to acquire resistance the use of metallo-β-lactamases (MBLs), a family of dinuclear metalloenzyme...Antibiotic resistance has emerged as a major global threat to human health. Among the strategies employed by pathogens to acquire resistance the use of metallo-β-lactamases (MBLs), a family of dinuclear metalloenzymes, is among the most potent. MBLs are subdivided into three groups (i.e. B1, B2 and B3) with most of the virulence factors belonging to the B1 group. The recent discovery of AIM-1, a B3-type MBL, however, has illustrated the potential health threat of this group of MBLs. Here, we employed a bioinformatics approach to identify and characterize novel B3-type MBLs from Novosphingobium pentaromativorans and Simiduia agarivorans. These enzymes may not yet pose a direct risk to human health, but their structures and function may provide important insight into the design and synthesis of a still elusive universal MBL inhibitor.展开更多
Metallo-β-lactamases (MBLs) are a family of Zn2+-dependent enzymes that have contributed strongly to the emergence and spread of antibiotic resistance. Novel members as well as variants of existing members of this fa...Metallo-β-lactamases (MBLs) are a family of Zn2+-dependent enzymes that have contributed strongly to the emergence and spread of antibiotic resistance. Novel members as well as variants of existing members of this family are discovered continuously, compounding their threat to global health care. MBLs are divided into three subgroups, i.e. B1, B2 and B3. The recent discovery of an unusual MBL from Serratia proteamaculans (SPR-1) suggests the presence of an additional subgroup, i.e. B4. A database search reveals that SPR-1 has only one homologue from Cronobacter sakazakii, CSA-1.These two MBLs have a unique active site and may employ a mechanism distinct from other MBLs, but reminiscent of some organophosphate-degrading hydrolases.展开更多
New Delhi metallo-β-lactamase (NDM-1) has created a medical storm ever since it was first reported;as it is active on virtually all clinically used β-lactam antibiotics. NDM-1 rampancy worldwide is now considered a ...New Delhi metallo-β-lactamase (NDM-1) has created a medical storm ever since it was first reported;as it is active on virtually all clinically used β-lactam antibiotics. NDM-1 rampancy worldwide is now considered a nightmare scenario, particularly due to its rapid dissemination. An underlying theme in the majority of recent studies is structural characterization as knowledge of the three-dimensional structure of NDM-1 shall help find connections between its structure and function. Moreover, structural details are even critical in order to reveal the resistance mecha- nism to β-lactam antibiotics. In this perspective, we review structural characteristics of NDM-1 that have been delineated since its first report. We anticipate that these structure-function connections made by its characterization shall further serve as future guidelines for elucidating pathways towards de novo design of functional inhibitors.展开更多
Background and Aim: Multi drug resistant Non fermenting gram negative bacilli (NFGNB) have emerged as a major cause of health-care associated infections especially in immunocompromised hosts. The aim of the study was ...Background and Aim: Multi drug resistant Non fermenting gram negative bacilli (NFGNB) have emerged as a major cause of health-care associated infections especially in immunocompromised hosts. The aim of the study was to investigate the prevalence of NFGNB as a cause of health-care associated infections (HAI) in cancer patients and determine their resistance pattern. Patients and Methods: During the study period, 158 NFGNB isolates were collected. Microscan Walk Away 9 was used for identification and testing for the metallo-β-lactamases (MBLs) was done by Imipenem-EDTA combined disk synergy test (CDST-IPM). Results: NFGNB represented 29.0% of infections caused by gram negative organisms. Carbapenem resistance, the multi-drug resistant (MDR) phenotype, and MBL production were documented in 70%, 63%, and 59% of NFGNB isolates, respectively. MDR-NFGNB rates were significantly higher among hospitalized patients, medical department and those with longer duration of hospital stay (p = 0.034, 0.026, 0.019;respectively) than non MDR-NFGNB. Conclusion: A high level of carbapenem and multi-drug resistance were detected among the non-fermenter pathogens isolated from hospitalized cases and were more frequently encountered in high risk adult cancer patients requiring longer duration of hospitalization. The MDR-NFGNB are constituting important causes of health-care associated infections in cancer patients.展开更多
The problem of drug resistance of Gram-negative bacteria has become increasingly serious and has aroused widespread public concern.The "super bacteria" producing New Delhi metallo-beta-lactamase(NDM-1) are r...The problem of drug resistance of Gram-negative bacteria has become increasingly serious and has aroused widespread public concern.The "super bacteria" producing New Delhi metallo-beta-lactamase(NDM-1) are resistant to almost all β-lactam antibiotics.However, clinically existing β-lactamase inhibitors are ineffective against metallo-β-lactamases(MBLs) including NDM-1.Therefore, effective NDM-1 inhibitors are urgently needed.In this study, a high-throughput screening model for NDM-1 inhibitors was optimized and used to screen NDM-1 inhibitors.As a result, IMB-XH1 was screened out as a novel NDM-1 inhibitor from 52 100 compounds of different sources.The combined use of IMB-XH1 can increase the sensitivity of E.coli BL21(DE3)(pET-30 a(+)-NDM-1) to β-lactam antibiotics.Enzymatic kinetic studies indicate that IMB-XH1 is a non-competitive inhibitor of NDM-1 and also has inhibitory activity against other MBLs such as IMP-4, ImiS and L1.As a novel NDM-1 inhibitor, its activity and mechanism of action need to be further explored.展开更多
Background In the present study, we characterized multidrug-resistant Pseudomonas aeruginosa （MDRP） clinical isolates from a paediatric facility and investigated the types and features of the metallo-β-lactamases ...Background In the present study, we characterized multidrug-resistant Pseudomonas aeruginosa （MDRP） clinical isolates from a paediatric facility and investigated the types and features of the metallo-β-lactamases （MBLs） produced by carbapenem-resistant strains. Methods Four hundred and ninety-eight strains of Pseudomonas aeruginosa were isolated from patients at Beijing Children＇s Hospital between January 2005 and December 2006. The minimal inhibition concentrations （MICs） of the strains for 13 antibiotics were measured. A combination of the E test and PCR amplification/DNA sequencing was used to define the carbapenem-resistant strains. Results We found that 24.1% （120/498） of the isolates were MDRP. The frequencies of resistance to imipenem and meropenem were 34.2% and 35.8%, respectively, and the MIC50 and MIC90values for the two antibiotics were identical at 4 pg/ml and 32 pg/ml, respectively. The detection rate for carbapenem resistance was 49.2% （59/120）. Among the 59 carbapenem-resistant Pseudomonas aeruginosa strains, 39 （66.1%） were positive for the MBL genotype; 35 （89.7%） strains carried the blaiMp gene and 4 （10.3%） strains carried the blavm gene. Neither blasPM nor blaGiM was amplified from any of the 59 isolates. DNA sequencing revealed that IMP-1 was present in 35 IMP-producing isolates and VIM-2 was detected in four VIM-producing isolates. Conclusions These MDRP isolates exhibited high frequencies of resistance to carbapenems among clinical isolates from a paediatric facility in Beijing, China. The production of MBL appears to be an important mechanism for carbapenem resistance in Pseudomonas aeruginosa.展开更多
Objective： To review the origin, diagnosis, treatment and public health concern of New Delhi metallo-β-lactamase （NDM）-producing bacteria. Data Sources： We searched database for studies published in English. The ...Objective： To review the origin, diagnosis, treatment and public health concern of New Delhi metallo-β-lactamase （NDM）-producing bacteria. Data Sources： We searched database for studies published in English. The database of PubMed from 2007 to 2015 was used to conduct a search using the keyword term ＂NDM and Acinetobacter or Enterobacteriaceae or Pseudomonas aeruginosa.＂ Study Selection： We collected data including the relevant articles on international transmission, testing methods and treatment strategies of NDM-positive bacteria. Worldwide NDM cases were reviewed based on 22 case reports. Results： The first documented case of infection caused by bacteria producing NDM- 1 occurred in India, in 2008. Since then, 13 blaNDM variants have been reported. The rise of NDM is not only due to its high rate of genetic transfer among unrelated bacterial species, but also to human factors such as travel, sanitation and food production and preparation. With limited treatment options, scientists try to improve available therapies and create new ones. Conclusions： In order to slow down the spread of these NDM-positive bacteria, a series of measures must be implemented. The creation and transmission of blaNDM are potentially global health issues, which are not issues for one country or one medical community, but for global priorities in general and for individual wound care practitioners specifically.展开更多
New Delhi metallo-b-lactamase-1(NDM-1)is capable of hydrolyzing nearly allβ-lactam antibiotics,posing an emerging threat to public health.There are currently less effective treatment options for treating NDM-1 positi...New Delhi metallo-b-lactamase-1(NDM-1)is capable of hydrolyzing nearly allβ-lactam antibiotics,posing an emerging threat to public health.There are currently less effective treatment options for treating NDM-1 positive"superbug",and no promising NDM-1 inhibitors were used in clinical practice.In this study,structure eactivity relationship based on thiosemicarbazone derivatives wassystematically characterized and their potential activities combined with meropenem(MEM)were evaluated.Compounds 19 bg and 19 bh exhibited excellent activity against 10 NDM-positive isolate clinical isolates in reversing MEM resistance.Further studies demonstrated compounds 19 bg and 19 bh were uncompetitive NDM-1 inhibitors with Ki Z 0.63 and 0.44 mmol/L,respectively.Molecular docking speculated that compounds 19 bg and 19 bh were most likely to bind in the allosteric pocket which would affect the catalytic effect of NDM-1 on the substrate meropenem.Toxicity evaluation experiment showed that no hemolysis activities even at concentrations of 1000 mg/m L against red blood cells.In vivo experimental results showed combination of MEM and compound 19 bh was markedly effective in treating infections caused by NDM-1 positive strain and prolonging the survival time of sepsis mice.Our finding showed that compound 19 bh might be a promising lead in developing new inhibitor to treat NDM-1 producing superbug.展开更多
New Delhi metallo-b-lactmase-1（NDM-1） catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover...New Delhi metallo-b-lactmase-1（NDM-1） catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover novel agents to treat this superbug, an old drug methisazone was found to be a weak NDM-1 inhibitor, with an IC50 of 297.6 mmol/L. Based on this result, a series of isatin-β-thiosemicarbazones（IBTs）were synthesized and biologically evaluated as novel NDM-1 inhibitors. Nine of the IBT compounds showed IC50 values of 〈10 mmol/L, the best of which was 2.72 mmol/L. Comparative field analysis（Co MFA） contour maps were generated to depict the structural features and molecular docking was performed to understand the possible binding mode of these inhibitors. The present research hereby has provided valuable information for further discovery of NDM-1 inhibitors.展开更多
In an effort to understand the recombination of a B2 metallo-β-lactamase（MβL）,the binding of metals to apo-ImiS was studied by isothermal titration calorimetry and fluorescence spectra.The binding of Zn（Ⅱ）,Co...In an effort to understand the recombination of a B2 metallo-β-lactamase（MβL）,the binding of metals to apo-ImiS was studied by isothermal titration calorimetry and fluorescence spectra.The binding of Zn（Ⅱ）,Co（Ⅱ） to apo-lmiS resulted in activation free energies △G_≠~θ values of 93.719 and 92.948 kJ mol^（-1）,respectively,and increasing of fluorescence intensity at maxima emission of 340 nm.展开更多
New Delhi metallo-β-lactamase 1(NDM-1) can hydrolyze most β-lactam antibiotics, which is the major factor for drug resistance of Gram-negative bacteria. The binding of most reversible inhibitors to NDM-1 is relative...New Delhi metallo-β-lactamase 1(NDM-1) can hydrolyze most β-lactam antibiotics, which is the major factor for drug resistance of Gram-negative bacteria. The binding of most reversible inhibitors to NDM-1 is relatively weak due to the shallow active pocket of NDM-1. Alternatively, irreversible covalent inhibitors can prevent their dissociation from the target, leading to permanent inactivation of the protein.Herein, we report a series of irreversible covalent inhibitors of NDM-1 targeting the conserved Lys211 in the active pocket. Several methods, including mass spectrometry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fluorescent labeling, and coumarin probe were used to demonstrate that pentafluorophenyl ester formed a covalent bond with Lys211. Moreover, our target inhibitor, in combination with meropenem, achieved an antibacterial effect on drug-resistant bacteria, along with an excellent safety profile. Our new strategy in designing lysine-targeted irreversible covalent NDM-1 inhibitors provides a potential option for the clinical treatment of Gram-negative bacteria.展开更多
Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1(NDM-1)are a type of newly discovered antibioticresistant bacteria.The rapid pandemic spread of NDM-1 bacteri...Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1(NDM-1)are a type of newly discovered antibioticresistant bacteria.The rapid pandemic spread of NDM-1 bacteria worldwide(spreading to India,Pakistan,Europe,America,and Chinese Taiwan)in less than 2 months characterizes these microbes as a potentially major global health problem.The drug resistance of NDM-1 bacteria is largely due to plasmids containing the blaNDM-1 gene shuttling through bacterial populations.The NDM-1 enzyme encoded by the blaNDM-1 gene hydrolyzes β-lactam antibiotics,allowing the bacteria to escape the action of antibiotics.Although the biological functions and structural features of NDM-1 have been proposed according to results from functional and structural investigation of its homologues,the precise molecular characteristics and mechanism of action of NDM-1 have not been clarified.Here,we report the threedimensional structure of NDM-1 with two catalytic zinc ions in its active site.Biological and mass spectroscopy results revealed that D-captopril can effectively inhibit the enzymatic activity of NDM-1 by binding to its active site with high binding affinity.The unique features concerning the primary sequence and structural conformation of the active site distinguish NDM-1 from other reported metallo-β-lactamases(MBLs)and implicate its role in wide spectrum drug resistance.We also discuss the molecular mechanism of NDM-1 action and its essential role in the pandemic of drug-resistant NDM-1 bacteria.Our results will provide helpful information for future drug discovery targeting drug resistance caused by NDM-1 and related metallo-β-lactamases.展开更多
Background: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clini...Background: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clinical characteristics and molecular epidemiology of ESBL-producing E. coli and K. pneumoniae causing pneumonia at a large teaching hospital in China. Methods: We collected patient's clinical data and ESBL-producing E. coli and K. pneumoniae strains causing pneumonia (from December 2015 to June 2016) at a hospital in Wuhan. The susceptibilities, multi-locus sequence typing, homologous analysis, ESBL genes by polymerase chain reaction and sequencing were determined. Results: A total of 59 ESBL-producing strains (31 E. coli and 28 K. pneumoniae) isolated from patients with pneumonia were analyzed. The majority of strains were isolated from patients were with hospital-acquired pneumonia (37/59, 62.7%), followed by community-acquired pneumonia (13/59, 22.0%), and ventilator-related pneumonia (9/59, 15.3%). The E. coli ST131 (9 isolates, 29.0%) and K. pneumoniae ST11 (5 isolates, 17.9%) were the predominant sub-types. The most prevalent ESBL gene was CTX-M-14, followed by SHV-77, CTX-M-3, SHV-11, and CTX-M-27. At least 33 (55.9%) of the ESBL-producing strains carried two or more ESBL genes. The ISEcp1 and IS26 were found upstream of all blaCTX-M (CTX-Ms) and of most blaSHV (SHVs)(57.6%), respectively. Moreover, three ESBL-producing K. pneumoniae ST11 strains which were resistant to carbapenems carried the blaNDM-1 and blaKPC-2, two of which also bearing blaOXA-48 were resistant to all antibiotics (including Tigecycline). Conclusions: Hospital-acquired pneumonia is more likely correlated with ESBL-producing E. coli and K. pneumoniae. ESBL-producing E. coli ST131 and multi-drug resistance ESBL-producing, as well as New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemases-2 (KPC-2) bearing K. pneumoniae ST11 are spreading in patients with pneumonia in hospital.展开更多
文摘Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.
基金Qazvin University of Medical Sciences for supporting the project(Grant number:10016).
文摘Background:Acinetobacter baumannii(A.baumannii)is known as an opportunistic pathogen related to health-care-associated infection that has a high antibiotic resistance potential,notably against carbapenems that are widely used to combat A.baumannii infections.This study aimed to detect oxacillin-hydrolyzing(OXA)carbapenemases and metallo-β-lactamases(MBL)among carbapenem-resistant A.baumannii isolated strains and to determine their clonal relationship by repetitive extragenic palindromic PCR(rep-PCR).Methods:In the present study,a total of 211 non-repetitive isolates of A.baumannii were collected from Qazvin educational hospitals(2016–2017).The disk diffusion method was used to investigate the antibiotic susceptibility of studied strains,followed by the detection of MBL and OXA-type genes using polymerase chain reaction(PCR)and sequencing methods.The rep-PCR method assessed the clonal relationship of carbapenem-non-susceptible A.baumannii isolates.Result:The obtained results showed that 87.2%and 86.7%of isolates were non-susceptible to imipenem and meropenem.The blaOXA-24(93.5%)was the most frequent gene,followed by the blaOXA-23(4.34%),blaIMP-1(1.63%),and blaVIM-1(0.54%).Meanwhile,blaOXA-58 and blaOXA-143 genes were not found.81.5%and 66.1%of isolates contained ISAba1 upstream of the blaOXA-23 and blaOXA-58 genes,respectively.Rep-PCR results revealed the carbapenem non-susceptible isolates belonged to three distinct clones:A 171(81%),B 34(16.1%),and C 6(2.8%).Conclusions:The results indicated a high prevalence of carbapenem-non-susceptible A.baumannii,with the emergence of the blaOXA-24 gene as the most common gene and the notable prevalence of MBL genes.These results revealed the need for appropriate therapeutic and infection control strategies and monitoring susceptibility patterns for controlling A.baumannii infections.
基金a grant from National Natu-ral Science Foundation of China (No. 30370079)
文摘To investigate the distribution of the genes of two major metallo-β-1actamases （MBL;i.e.,IMP and VIM） and class 1 integrons （intI） in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for blaIMP-1, blaVIM and blaVIM-2 genes. The MBL-positive isolates were further assessed for class 1 integrons by PCRusing specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the blaVIM gene was found in 81.5% （53/65） of all isolates, blaVIM-2 gene was found in only 1 isolate and the intl gene was observed in 45.3% （24/53） of blaVIM-positive isolates. One isolate carried simultaneously both blaIMP-1 and intl genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM β-1actamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P.aeruginosa.
文摘Objective:To detect and evaluate the various methods for metallo-β-lactamases(MBL) production in Pseudomonas aeruginosa(P.aeruginosa) and Acinetobacter species.Methods:A total of 109 P.aeruginosa and 85 Acinetobacter species were screened for imipenem resistance by Kirby- Bauer disc diffusion methods.Detection of MBL production was(lone by imipenem-EDTA combined disc test,double disc synerygy test(DDST) and imipenem-EDTA MBL E test.Results: A total of 63(57.8%) strains of P.aeruginosa and 46(54.1%) strains of Acinetobacter spp.were found to be resistant to imipenem.Of the 63 imipenem resistant P.aeruginosa tested for MBL production.44(69.89;) were found to be positive and among 46 imipenem resistant Acinetobacter. 19(41.3%) were shown to be the MBL producers.Conclusions:Imipenem-EDTA combined disc test and MBL E test are equally effective for MBL detection in both P.aeruginosa and Acinetobacter spp.,but given the cost-constraints,combined disc can be used as a convenient screening method in the clinical microbiology laboratory.
基金N.M.thanks the Science Foundation Ireland(SFI)for financial support in form of a President of Ireland Young Researcher Award(PIYRA) G.S.acknowledges the award of a Future Fellowship from the Australian Research Council(FT120100694)and is grateful to the National Health and Medical Research Council of Australia for funding.
文摘Antibiotic resistance is one of the most significant challenges facing global healthcare. Since the 1940s, antibiotics have been used to fight infections, initially with penicillin and subsequently with various derivatives including cephalosporins, carbapenams and monobactams. A common characteristic of these antibiotics is the four-memberedβ-lactam ring. Alarmingly, in recent years an increasing number of bacteria have become resistant to these antibiotics. A major strategy employed by these pathogens is to use Zn(II)-dependent enzymes, the metallo-β-lactamases (MBLs), which hydrolyse theβ-lactam ring. Clinically useful MBL inhibitors are not yet available. Consequently, MBLs remain a major threat to human health. In this review biochemical properties of MBLs are discussed, focusing in particular on the interactions between the enzymes and the functionally essential metal ions. The precise role(s) of these metal ions is still debated and may differ between different MBLs. However, since they are required for catalysis, their binding site may present an alternative target for inhibitor design.
文摘Pseudomonas aeruginosa is a major cause of nosocomial infections with high mortality rates. The organism is highly resistant to most classes of drugs used and can develop resistance during treatment. One of the resistance mechanisms of P. aeruginosais is Metallo-β-Lactamase (MBL) production. MBL producing P. aeruginosa is a major health concern given it’s resistance to almost all available drugs. The prevalence of this resistant strain is unknown since there is no standardized method for testing MBL production. This was a laboratory based cross-sectional prospective study that was carried out from September 2015 to March 2016 at Kenyatta National Hospital. Ninety-nine isolates of P. aeruginosa were collected during the period and tested for antimicrobial susceptibility and isolates found to be resistant to imipenem tested for MBL production. The results indicated high resistance of P. aeruginosa to commonly used drugs. Of the isolates tested 69.7% were resistant to piperacillin, 63.6% were resistant to aztreonam, 58.6% were resistant to levofloxacin, 55.6% were resistant to cefipime, 65.7% were resistant to ceftazidime, 68.7% were resistant to ticarcillin-clavulanate, 72.2% were resistant to meropenem, 64.9% were resistance to imipenem while 86.4% of urine isolates were resistant to ofloxacin. Of the isolates resistant to imipenem 87.3% were found to be MBL producers. In conclusion, P. aeruginosais highly resistant to the drugs currently is used for treatment and resistance to carbapenems is largely due to MBL production.
基金N.M.thanks the Science Foundation Ireland(SFI)for financial support in form of a President of Ireland Young Researcher Award(PIYRA)G.S.acknowledges the award of a Future Fellowship from the Australian Research Council(FT120100694)is grateful to the National Health and Medical Research Council of Australia for funding.
文摘Antibiotic resistance has emerged as a major global threat to human health. Among the strategies employed by pathogens to acquire resistance the use of metallo-β-lactamases (MBLs), a family of dinuclear metalloenzymes, is among the most potent. MBLs are subdivided into three groups (i.e. B1, B2 and B3) with most of the virulence factors belonging to the B1 group. The recent discovery of AIM-1, a B3-type MBL, however, has illustrated the potential health threat of this group of MBLs. Here, we employed a bioinformatics approach to identify and characterize novel B3-type MBLs from Novosphingobium pentaromativorans and Simiduia agarivorans. These enzymes may not yet pose a direct risk to human health, but their structures and function may provide important insight into the design and synthesis of a still elusive universal MBL inhibitor.
基金N.M.thanks the Science Foundation Ireland(SFI)for financial support in the form of a President of Ireland Young Researcher Award(PIYRA)G.S.acknowledges the award of a Future Fellowship from the Australian Research Council(FT120100694)D.O.and G.S.are grateful to the National Health and Medical Research Council of Aus-tralia for funding.
文摘Metallo-β-lactamases (MBLs) are a family of Zn2+-dependent enzymes that have contributed strongly to the emergence and spread of antibiotic resistance. Novel members as well as variants of existing members of this family are discovered continuously, compounding their threat to global health care. MBLs are divided into three subgroups, i.e. B1, B2 and B3. The recent discovery of an unusual MBL from Serratia proteamaculans (SPR-1) suggests the presence of an additional subgroup, i.e. B4. A database search reveals that SPR-1 has only one homologue from Cronobacter sakazakii, CSA-1.These two MBLs have a unique active site and may employ a mechanism distinct from other MBLs, but reminiscent of some organophosphate-degrading hydrolases.
文摘New Delhi metallo-β-lactamase (NDM-1) has created a medical storm ever since it was first reported;as it is active on virtually all clinically used β-lactam antibiotics. NDM-1 rampancy worldwide is now considered a nightmare scenario, particularly due to its rapid dissemination. An underlying theme in the majority of recent studies is structural characterization as knowledge of the three-dimensional structure of NDM-1 shall help find connections between its structure and function. Moreover, structural details are even critical in order to reveal the resistance mecha- nism to β-lactam antibiotics. In this perspective, we review structural characteristics of NDM-1 that have been delineated since its first report. We anticipate that these structure-function connections made by its characterization shall further serve as future guidelines for elucidating pathways towards de novo design of functional inhibitors.
文摘Background and Aim: Multi drug resistant Non fermenting gram negative bacilli (NFGNB) have emerged as a major cause of health-care associated infections especially in immunocompromised hosts. The aim of the study was to investigate the prevalence of NFGNB as a cause of health-care associated infections (HAI) in cancer patients and determine their resistance pattern. Patients and Methods: During the study period, 158 NFGNB isolates were collected. Microscan Walk Away 9 was used for identification and testing for the metallo-β-lactamases (MBLs) was done by Imipenem-EDTA combined disk synergy test (CDST-IPM). Results: NFGNB represented 29.0% of infections caused by gram negative organisms. Carbapenem resistance, the multi-drug resistant (MDR) phenotype, and MBL production were documented in 70%, 63%, and 59% of NFGNB isolates, respectively. MDR-NFGNB rates were significantly higher among hospitalized patients, medical department and those with longer duration of hospital stay (p = 0.034, 0.026, 0.019;respectively) than non MDR-NFGNB. Conclusion: A high level of carbapenem and multi-drug resistance were detected among the non-fermenter pathogens isolated from hospitalized cases and were more frequently encountered in high risk adult cancer patients requiring longer duration of hospitalization. The MDR-NFGNB are constituting important causes of health-care associated infections in cancer patients.
基金Natural Sciences Foundation of China(NSFC,Grant No.81872913)the CAMS Initiative for Innovative Medicine(Grant No.2016-I2M-1-013)+1 种基金the Fundamental Research Funds for Central Public-interest Scientific Institution(Centre for Tuberculosis)(Grant No.2016ZX310183-3)the National High-tech R&D Program(863 Program,Grant No.2015AA020911)
文摘The problem of drug resistance of Gram-negative bacteria has become increasingly serious and has aroused widespread public concern.The "super bacteria" producing New Delhi metallo-beta-lactamase(NDM-1) are resistant to almost all β-lactam antibiotics.However, clinically existing β-lactamase inhibitors are ineffective against metallo-β-lactamases(MBLs) including NDM-1.Therefore, effective NDM-1 inhibitors are urgently needed.In this study, a high-throughput screening model for NDM-1 inhibitors was optimized and used to screen NDM-1 inhibitors.As a result, IMB-XH1 was screened out as a novel NDM-1 inhibitor from 52 100 compounds of different sources.The combined use of IMB-XH1 can increase the sensitivity of E.coli BL21(DE3)(pET-30 a(+)-NDM-1) to β-lactam antibiotics.Enzymatic kinetic studies indicate that IMB-XH1 is a non-competitive inhibitor of NDM-1 and also has inhibitory activity against other MBLs such as IMP-4, ImiS and L1.As a novel NDM-1 inhibitor, its activity and mechanism of action need to be further explored.
文摘Background In the present study, we characterized multidrug-resistant Pseudomonas aeruginosa （MDRP） clinical isolates from a paediatric facility and investigated the types and features of the metallo-β-lactamases （MBLs） produced by carbapenem-resistant strains. Methods Four hundred and ninety-eight strains of Pseudomonas aeruginosa were isolated from patients at Beijing Children＇s Hospital between January 2005 and December 2006. The minimal inhibition concentrations （MICs） of the strains for 13 antibiotics were measured. A combination of the E test and PCR amplification/DNA sequencing was used to define the carbapenem-resistant strains. Results We found that 24.1% （120/498） of the isolates were MDRP. The frequencies of resistance to imipenem and meropenem were 34.2% and 35.8%, respectively, and the MIC50 and MIC90values for the two antibiotics were identical at 4 pg/ml and 32 pg/ml, respectively. The detection rate for carbapenem resistance was 49.2% （59/120）. Among the 59 carbapenem-resistant Pseudomonas aeruginosa strains, 39 （66.1%） were positive for the MBL genotype; 35 （89.7%） strains carried the blaiMp gene and 4 （10.3%） strains carried the blavm gene. Neither blasPM nor blaGiM was amplified from any of the 59 isolates. DNA sequencing revealed that IMP-1 was present in 35 IMP-producing isolates and VIM-2 was detected in four VIM-producing isolates. Conclusions These MDRP isolates exhibited high frequencies of resistance to carbapenems among clinical isolates from a paediatric facility in Beijing, China. The production of MBL appears to be an important mechanism for carbapenem resistance in Pseudomonas aeruginosa.
基金Source of Support： This study was supported by grants from National Natural Science Foundation of China （No. 81101288 and 81172737）. Conflict of Interest： None declared.
文摘Objective： To review the origin, diagnosis, treatment and public health concern of New Delhi metallo-β-lactamase （NDM）-producing bacteria. Data Sources： We searched database for studies published in English. The database of PubMed from 2007 to 2015 was used to conduct a search using the keyword term ＂NDM and Acinetobacter or Enterobacteriaceae or Pseudomonas aeruginosa.＂ Study Selection： We collected data including the relevant articles on international transmission, testing methods and treatment strategies of NDM-positive bacteria. Worldwide NDM cases were reviewed based on 22 case reports. Results： The first documented case of infection caused by bacteria producing NDM- 1 occurred in India, in 2008. Since then, 13 blaNDM variants have been reported. The rise of NDM is not only due to its high rate of genetic transfer among unrelated bacterial species, but also to human factors such as travel, sanitation and food production and preparation. With limited treatment options, scientists try to improve available therapies and create new ones. Conclusions： In order to slow down the spread of these NDM-positive bacteria, a series of measures must be implemented. The creation and transmission of blaNDM are potentially global health issues, which are not issues for one country or one medical community, but for global priorities in general and for individual wound care practitioners specifically.
基金supported by National Natural Science Foundation of China(Grant Nos.81903447 for Bing Zhao,81903623 for Yongfang Yao,81703328 for Liying Ma,and 81430085 for Hongmin Liu)National Key Research and Development Project of China(Nos.2016YFA0501800 and 2018YFE0195100 for Hongmin Liu)
文摘New Delhi metallo-b-lactamase-1(NDM-1)is capable of hydrolyzing nearly allβ-lactam antibiotics,posing an emerging threat to public health.There are currently less effective treatment options for treating NDM-1 positive"superbug",and no promising NDM-1 inhibitors were used in clinical practice.In this study,structure eactivity relationship based on thiosemicarbazone derivatives wassystematically characterized and their potential activities combined with meropenem(MEM)were evaluated.Compounds 19 bg and 19 bh exhibited excellent activity against 10 NDM-positive isolate clinical isolates in reversing MEM resistance.Further studies demonstrated compounds 19 bg and 19 bh were uncompetitive NDM-1 inhibitors with Ki Z 0.63 and 0.44 mmol/L,respectively.Molecular docking speculated that compounds 19 bg and 19 bh were most likely to bind in the allosteric pocket which would affect the catalytic effect of NDM-1 on the substrate meropenem.Toxicity evaluation experiment showed that no hemolysis activities even at concentrations of 1000 mg/m L against red blood cells.In vivo experimental results showed combination of MEM and compound 19 bh was markedly effective in treating infections caused by NDM-1 positive strain and prolonging the survival time of sepsis mice.Our finding showed that compound 19 bh might be a promising lead in developing new inhibitor to treat NDM-1 producing superbug.
基金supported by the “111” Project of Ministry of Education of China (No. B06005)the National Natural Science Foundation of China (No. 21672114)the National Basic Research Program of China (No. 2013CB734004)
文摘New Delhi metallo-b-lactmase-1（NDM-1） catalyzes the hydrolysis of b-lactam antibiotics and cleaves the b-lactam ring of the molecule, conferring bacterial resistance against these medicines. In an effort to discover novel agents to treat this superbug, an old drug methisazone was found to be a weak NDM-1 inhibitor, with an IC50 of 297.6 mmol/L. Based on this result, a series of isatin-β-thiosemicarbazones（IBTs）were synthesized and biologically evaluated as novel NDM-1 inhibitors. Nine of the IBT compounds showed IC50 values of 〈10 mmol/L, the best of which was 2.72 mmol/L. Comparative field analysis（Co MFA） contour maps were generated to depict the structural features and molecular docking was performed to understand the possible binding mode of these inhibitors. The present research hereby has provided valuable information for further discovery of NDM-1 inhibitors.
基金supported by the National Natural Science Foundation of China (Nos.21272186 and 81361138018)
文摘In an effort to understand the recombination of a B2 metallo-β-lactamase（MβL）,the binding of metals to apo-ImiS was studied by isothermal titration calorimetry and fluorescence spectra.The binding of Zn（Ⅱ）,Co（Ⅱ） to apo-lmiS resulted in activation free energies △G_≠~θ values of 93.719 and 92.948 kJ mol^（-1）,respectively,and increasing of fluorescence intensity at maxima emission of 340 nm.
基金funded by the National Natural Science Foundation of China (No. 82073688 to X. Sun and No. 82103971 to Y. Liang)Science and Technology Commission of Shanghai Municipality (No. 21S11907300 to X. Sun)Shanghai Science and Technology Development Fund from Central Leading Local Government (No. YDZX20223100001004 to X. Sun)。
文摘New Delhi metallo-β-lactamase 1(NDM-1) can hydrolyze most β-lactam antibiotics, which is the major factor for drug resistance of Gram-negative bacteria. The binding of most reversible inhibitors to NDM-1 is relatively weak due to the shallow active pocket of NDM-1. Alternatively, irreversible covalent inhibitors can prevent their dissociation from the target, leading to permanent inactivation of the protein.Herein, we report a series of irreversible covalent inhibitors of NDM-1 targeting the conserved Lys211 in the active pocket. Several methods, including mass spectrometry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fluorescent labeling, and coumarin probe were used to demonstrate that pentafluorophenyl ester formed a covalent bond with Lys211. Moreover, our target inhibitor, in combination with meropenem, achieved an antibacterial effect on drug-resistant bacteria, along with an excellent safety profile. Our new strategy in designing lysine-targeted irreversible covalent NDM-1 inhibitors provides a potential option for the clinical treatment of Gram-negative bacteria.
基金supported by the National Natural Science Foundation of China(Grant Nos.30870486 and 30730022)the National Major Projects(Grant Nos.2009ZX10004-804,2009ZX09311-001 and 2009ZX10004-304)the National Basic Research Program(973 Program)(Grant Nos.2011CB915501 and 2011CB910304).
文摘Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1(NDM-1)are a type of newly discovered antibioticresistant bacteria.The rapid pandemic spread of NDM-1 bacteria worldwide(spreading to India,Pakistan,Europe,America,and Chinese Taiwan)in less than 2 months characterizes these microbes as a potentially major global health problem.The drug resistance of NDM-1 bacteria is largely due to plasmids containing the blaNDM-1 gene shuttling through bacterial populations.The NDM-1 enzyme encoded by the blaNDM-1 gene hydrolyzes β-lactam antibiotics,allowing the bacteria to escape the action of antibiotics.Although the biological functions and structural features of NDM-1 have been proposed according to results from functional and structural investigation of its homologues,the precise molecular characteristics and mechanism of action of NDM-1 have not been clarified.Here,we report the threedimensional structure of NDM-1 with two catalytic zinc ions in its active site.Biological and mass spectroscopy results revealed that D-captopril can effectively inhibit the enzymatic activity of NDM-1 by binding to its active site with high binding affinity.The unique features concerning the primary sequence and structural conformation of the active site distinguish NDM-1 from other reported metallo-β-lactamases(MBLs)and implicate its role in wide spectrum drug resistance.We also discuss the molecular mechanism of NDM-1 action and its essential role in the pandemic of drug-resistant NDM-1 bacteria.Our results will provide helpful information for future drug discovery targeting drug resistance caused by NDM-1 and related metallo-β-lactamases.
基金a grant from the National Natural Science Foundation of China (No.81500005).
文摘Background: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clinical characteristics and molecular epidemiology of ESBL-producing E. coli and K. pneumoniae causing pneumonia at a large teaching hospital in China. Methods: We collected patient's clinical data and ESBL-producing E. coli and K. pneumoniae strains causing pneumonia (from December 2015 to June 2016) at a hospital in Wuhan. The susceptibilities, multi-locus sequence typing, homologous analysis, ESBL genes by polymerase chain reaction and sequencing were determined. Results: A total of 59 ESBL-producing strains (31 E. coli and 28 K. pneumoniae) isolated from patients with pneumonia were analyzed. The majority of strains were isolated from patients were with hospital-acquired pneumonia (37/59, 62.7%), followed by community-acquired pneumonia (13/59, 22.0%), and ventilator-related pneumonia (9/59, 15.3%). The E. coli ST131 (9 isolates, 29.0%) and K. pneumoniae ST11 (5 isolates, 17.9%) were the predominant sub-types. The most prevalent ESBL gene was CTX-M-14, followed by SHV-77, CTX-M-3, SHV-11, and CTX-M-27. At least 33 (55.9%) of the ESBL-producing strains carried two or more ESBL genes. The ISEcp1 and IS26 were found upstream of all blaCTX-M (CTX-Ms) and of most blaSHV (SHVs)(57.6%), respectively. Moreover, three ESBL-producing K. pneumoniae ST11 strains which were resistant to carbapenems carried the blaNDM-1 and blaKPC-2, two of which also bearing blaOXA-48 were resistant to all antibiotics (including Tigecycline). Conclusions: Hospital-acquired pneumonia is more likely correlated with ESBL-producing E. coli and K. pneumoniae. ESBL-producing E. coli ST131 and multi-drug resistance ESBL-producing, as well as New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemases-2 (KPC-2) bearing K. pneumoniae ST11 are spreading in patients with pneumonia in hospital.
