Background: Carbapenemase-producing Enterobacteriaceae (CPE) are an important and increasing threat to global health. They are nowadays more encountered routinely in hospitals and cause high morbidity and mortality du...Background: Carbapenemase-producing Enterobacteriaceae (CPE) are an important and increasing threat to global health. They are nowadays more encountered routinely in hospitals and cause high morbidity and mortality due to limited therapeutic alternatives. This study sought to determine the prevalence of CPE in Yaoundé teaching hospital, Cameroon, and the associated risk factors. Materials and Method: To achieve this goal, a descriptive cross-sectional study coupled to an analytical component with consecutive collection of Enterobacteria strains was carried out during a three-month period (from 27<sup>th</sup> July to 24<sup>th</sup> October 2018) in the University Teaching Hospital of Yaoundé, Cameroon. The oxidase and biochemical identification tests using a miniaturized Api 20 E system were performed on colonies grown on Eosin Methylene Blue (EMB) medium and subcultured on nutrient agar. Drug susceptibility testing was carried out according to the Antibiogram Committee of the French Society of Microbiology (CA-SFM 2018.V.2.0). The detection of carbapenemase production was performed by the CA-SFM 2018 algorithm for the screening of carbapenemase-producing enterobacteriaceae and its classification by inhibitory synergy tests. Results: Out of the 104 isolates, Escherichia coli (50%) was the most prevalent species, followed by Klebsiella pneumoniae (37.5%) and Citrobacter frendii (12.5%). Drugs susceptibility patterns showed a high resistance to penicillins group (97.4% to amoxicillin), cephalosporins (68.4% to cefotaxim, 58.1% to cefixim, 60.7% to ceftazidim, 57.1% of cefoxitin) and aztreonam (55.7%). However, 11.9% carbapenems related resistance was noticed: 14.4% to imipenem, 13.8% to ertapenem and 7.5% to meropenem. Numerous co-resistance to quinolones (65.8%), fluoroquinolones (49.6%), aminoglycosides (49.6%) and cotrimoxazole (71.8%) were also observed. From 104 isolates, AmpC production represented 23.08% (25/104) and 36.54% (38/104) were ESBL-isolates. The overall prevalence of CPE was 25% (26/104) with K.pneumoniae predominant (61.53%). Besides, Class A and class B carbapenemase were mainly produced with respectively 20% (21/104) and 5% (5/104). Univariate analysis revealed a significant association of carbapenemase production to Klebsiella pneumoniae (p = 0.01), ESBL and AmpC production ((P = 0.01 and P = 0.001 respectively) while that association was only significant to Klebsiella spp (p = 0.04) and AmpC production (p = 0.02) in multivariate analysis. Conclusion: The multi-resistance of Enterobacteriaceae to antibiotics in Cameroon has considerably increased. More attention should be paid to those bacteria to stall antimicrobial resistance spread.展开更多
Background and Purpose: The reintroduction of colistin as a last resort treatment against multi-resistant Gram-negative bacilli, is currently challenged by the emergence of colistin-resistant bacteria. The aim of this...Background and Purpose: The reintroduction of colistin as a last resort treatment against multi-resistant Gram-negative bacilli, is currently challenged by the emergence of colistin-resistant bacteria. The aim of this study was to assess the susceptibility of Pseudomonas and Acinetobacter strains to colistin, to identify carbapenemase production, and to investigate the plasmid genes involved in colistin resistance and carbapenemase production. Methodology: In order to establish the susceptibility profiles of 17 strains of Pseudomonas and Acinetobacter to colistin, their Minimum Inhibitory Concentrations (MICs) were determined using the liquid microdilution method. The possible production of carbapenemases was investigated with the modified Carbapenem Inactivation Method (mCIM). The search for genes encoding carbapenemases (bla<sub>OXA</sub>, bla<sub>IMP</sub>, bla<sub>Carba</sub>) and those responsible for plasmid resistance to colistin (mcr-1 and mcr-2) was performed by conventional PCR. Results and Conclusion: Ninety-four percent (94%) (16/17) of the strains were resistant to colistin. Intraspecies distribution was 50% (8/16), 31% (5/16), 13% (2/16) and 6% (1/16) for Acinetobacter baumannii, Pseudomonas aeruginosa, Pseudomonas luteola, and Pseudomonas fluorescens, respectively. Twenty-nine percent (29%) (6/17) of the strains produced carbapenemases. No mcr-1 and mcr-2 plasmid genes were detected. On the other hand, 17.6% (3/17) of the strains possessed the carbapenemase genes distributed as follows: Carba type (60%), OXA type (40%) and IMP type (0%). The results of this study highlight a high resistance to colistin in strains belonging to the genera Acinetobacter and Pseudomonas, and some of these strains produce carbapenemases.展开更多
Background and Objective: Nowadays, the clinical utility of carbapenems is threatened by the emergence of resistant bacteria, favored by its increasing use. According to the WHO, Acinetobacter baumannii: nosocomial in...Background and Objective: Nowadays, the clinical utility of carbapenems is threatened by the emergence of resistant bacteria, favored by its increasing use. According to the WHO, Acinetobacter baumannii: nosocomial infection agent, tops the list of priority antibiotic-resistant pathogens, considered to be the riskiest for humans. This study sought to determine the prevalence of carbapenemase-producing Acinetobacter baumannii strains in four health facilities in the Center and Littoral regions of Cameroon and the associated risk factors. Materials and Method: An analytical cross-sectional study was conducted over a six-month period from January to June 2022. All suspicious A. baumanii isolates obtained from pathological samples at the bacteriology laboratory of the different health facilities were systematically collected and re-identified. Re-identification and antimicrobial susceptibility Testing (AST) were performed using the VITEK 2 System and the Kirby-Bauer method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Detection and phenotypic characterization of carbapenemases was performed according to adequate standard procedures. Results: A total of 168/226 clinical isolates of Acinetobacter baumannii were confirmed after re-identification, among which 52.69% derived from male patients, 55.09% from participants aged between 10 - 39 years old, and 46.71% from pus samples. A very high resistance rates to all families of antibiotics was noted, except to colistin (10.2%). 40.12% of these isolates produced carbapenemase, represented by 62.69% of class B and 37.31% of class A. Carbapenemase production was observed only at HMR1, Centre region and at Laquintinie hospital, Littoral region with 53.33% and 50% respectively, even if there is no significant difference (P = 0.81). In addition, frequent hospitalisation was significantly associated to the production of carbapenemase among A. baumanii (Adjusted-OR = 16.53, P-value 0.0001). Conclusion: This study highlighted the emergence of carbapenemase-producing Acinetobacter baumannii which is increasingly growing. Continuous drug-resistant monitoring and preventive measures could help to prevent and curb the dissemination of A. baumanii resistance genes, especially in health settings.展开更多
Carbapenemase-producing Enterobacteriaceae(CPE) isolates are recognized as one of the most severe threats to public health. However, the population structure and genetic characteristics of CPE isolates among bloodstre...Carbapenemase-producing Enterobacteriaceae(CPE) isolates are recognized as one of the most severe threats to public health. However, the population structure and genetic characteristics of CPE isolates among bloodstream infections(BSIs) are largely unknown. To address this knowledge gap, in this study,we included patients with clinically significant BSIs due to Enterobacterales isolates, recruited from 26 sentinel hospitals in China(2014–2015). CPE isolates were microbiologically and genomically characterized,including their susceptibility profiles, molecular typing, phylogenetic features, and genetic context analysis of carbapenemase-encoding genes. Of the 2569 BSI Enterobacterales isolates enrolled, 42(1.6%) were carbapenemase-positive. Moreover, among the 2242 investigated isolates, 1111(49.6%) extendedspectrum β-lactamase(ESBL)-producing isolates were identified in Escherichia coli(E. coli), Klebsiella pneumoniae(K. pneumoniae), Proteus mirabilis(P. mirabilis), and Klebsiella oxytoca. Whole genome sequencing analysis showed the clonal spread of K. pneumoniae carbapenemase(KPC)-2-producing K. pneumoniae sequence type(ST) 11 and New Delhi metallo-β-lactamase(NDM)-5-producing E. coli ST167 in our collection. Plasmid analysis revealed that carbapenemase-encoding genes were located on multiple plasmids. A high prevalence of biofilm-encoding type 3 fimbriae clusters and yesiniabactin-associated genes was observed in K. pneumoniae isolates. This work demonstrates the high prevalence of ESBLs and the wide dissemination of CPE among BSI isolates in China, which represent real clinical threats. Moreover, our findings first illustrate a more comprehensive genome scenario of CPE isolates among BSIs. The clonal spread of KPC-2-producing K. pneumoniae ST11 and NDM-5-producing E. coli ST167 needs to be closely monitored.展开更多
Objective:To assess and characterize antibiotic resistance in Acinetobacter baumannii strains recovered from 5 health-care facilities in Algiers.Methods:Antibiotic susceptibility testing was performed by agar diffusio...Objective:To assess and characterize antibiotic resistance in Acinetobacter baumannii strains recovered from 5 health-care facilities in Algiers.Methods:Antibiotic susceptibility testing was performed by agar diffusion and agar dilution methods,resistance genes were identified by PCR and sequencing,and molecular typing of isolates was carried out by enterobacterial repetitive intergenic consensus-PCR(ERIC-PCR).Results:Among 125 tested isolates,117(93.6% ) were multidrug-resistant.of which 94(75.2% ) were imipenem resistant.The bla_(ADC)and bla_(OXA-51-like) genes were detected in all isolates,in association with ISAba I sequence in 84% and 8% (imipenem resistant) of isolates,respectively.The bla_(OXA-23-like) and bla_(OXA-24-like)carbapenemase genes were delected in 67.02% and 20.21% of imipenem-resistant isolates,respectively.The bla_(OXA-23-like) gene is linked to ISAba1 or ISAba4 elements.The metallo-β-lactamase NDM-1 gene was found in 10(10.6% ) imipenem-resisianl strains from three hospitals,it is linked to ISAba125 clement in nine strains.Extended spectrum β-lactamases production was not detected.Imipenem and cefotaxime resistance phenolypes could not be transferred to Escherichia coli by conjugation.Outer membrane protein CarO gene was not delected in four imipenem-resisianl isolates.The aac(6')-1b.sul1,sul2,tetA and tetB genes were present in 5.31% .36.17% .77.65% .1.06% and 65.92% of strains,respectively.Class 1 integrons were detected in 23.4% strains.KRIC-PCR typing showed a genetic diversity among bla_(OXA-23-like) and bla_(OXA-24-like) positive strains,while clonality was observed among bla_(NDM-1)positives.Conclusions:This study highlighted the high prevalence of imipenem resistance in Acinetobacter baumannii in Algiers hospitals mediated mainly by bla_(OXA-23-like),bla_(OXA-24-like),and bla_(NDM-1) genes.展开更多
<b>Background:</b> The increasing resistance of bacteria to various antibiotics is a worldwide public health issue. Carbapenems that have elicited great hope in treating infections caused by multidrug-resi...<b>Background:</b> The increasing resistance of bacteria to various antibiotics is a worldwide public health issue. Carbapenems that have elicited great hope in treating infections caused by multidrug-resistant germs have seen their efficacy narrowed over time with the emergence of other novel resistance mechanisms, notably the production of Carbapenemases. <b>Methods:</b> A prospective cross-sectional study was conducted from May 2017 to May 2018 in Douala (Cameroon) to detect carbapenemase-producing Gram-negative bacilli. Isolated strains were identified using the Vitek2<sup>TM</sup> system. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method on agar plates with 20 selected commercially available antibiotic discs. The bacterial strains were tested for the production of three Carbapenemases (OXA-48, NDM, KPC), using an immuno-chromatographic technique, with the “RESIST-3 O.K.N. K-SeT” rapid detection kit. <b>Results:</b> During the study period, 1687 strains of Gram-negative bacilli were isolated in selected laboratories with a total of 200 multi-resistant strains identified (11.9%). Among the multi-resistant strains, <i>E. coli</i> was the species most represented in <i>Enterobacteriaceae</i> (27.5%) followed by <i>K. pneumoniae</i> (15.5%) and the non-fermenting Gram-negative bacilli were predominantly <i>P. aeruginosa</i> (20.5%). These strains mainly came from urine and pus, <i>i.e.</i> 41% and 32% respectively. Thirty-two (16%) strains produced one of the Carbapenemases with a higher frequency at the General Hospital (84%). NDM-type carbapenemase was the most frequently identified (8.5%), OXA-48 type 7.5%, and no KPC production was observed. Among the <i>Enterobacteriaceae</i> 22.9% produced Carbapenemases and only 5.1% of the non-fermenting bacilli produced these enzymes. The isolates strains were completely resistant to all antibiotics except Amikacin and Fosfomycin. The strains producing the NDM-type carbapenemase showed higher rates of resistance to almost all of the antibiotics tested. <b>Conclusion:</b> Multidrug-resistant strains are experiencing an increase in evolution. The apparition of strains producing Carbapenemases prominently, the NDM and OXA-48 favor this increase. The activities of antibiotics with high efficacies on these strains are low.展开更多
In recent years,the mobile metallo-β-lactamase(MBL)genes have been found to correspond to one of the most important resistance characters identified in Gramnegative bacteria,severely affecting clinical chemotherapy a...In recent years,the mobile metallo-β-lactamase(MBL)genes have been found to correspond to one of the most important resistance characters identified in Gramnegative bacteria,severely affecting clinical chemotherapy and threatening public health.The prevalence of mobile MBL genes and their flanking regions in Gram-negative bacteria from diseased pigs in China was investigated.A total of 334 lung samples from diseased pigs were screened for Gram-negative bacteria classified as non-susceptible to meropenem(MIC≥4mg·L^(–1)).Six isolates,including three Escherichia coli,two Acinetobacter baumanii and one A.calcoaeticus,exhibitedMBL production and carried the blaNDM-1 gene.S1-PFGE and Southern blot analysis showed that the blaNDM-1 gene was located on the chromosome of one A.baumanii isolate and on plasmids of various sizes in the other five isolates.MIC testing using broth microdilution revealed that all blaNDM-1-carrying isolates and some of their transconjugants exhibited resistance to almost allβ-lactams tested.Whole genome sequencing revealed that the flanking region of the blaNDM-1 gene from all porcine isolates had high levels of similarity with the corresponding regions in human isolates.One porcine E.coli isolate carrying blaNDM-1 was typed as ST48,a common sequence type in human E.coli isolates.These results suggest the possibility of human-tofood animal transfer of blaNDM-1-producing E.coli,highlighting the need for surveillance of carbapenemase producers among bacteria from food animals.In addition,the prudent use of antimicrobial agents to decrease the opportunities for co-selection of carbapenemase genes in food animals is also urgently needed.展开更多
The rapid spread of carbapenemase-producing Klebsiella pneumoniae(cpKP)poses serious threats to public health;however,the underlying genetic basis for its dissemination is still unknown.We conducted a comprehensive ge...The rapid spread of carbapenemase-producing Klebsiella pneumoniae(cpKP)poses serious threats to public health;however,the underlying genetic basis for its dissemination is still unknown.We conducted a comprehensive genomic epidemiology analysis on 420 cpKP isolates collected from 70 hospitals in 24 provinces/autonomous regions/municipalities of China during 2009–2017 by short-/long-read sequencing.The results showed that most cpKP isolates were categorized into clonal group 258(CG258),in which ST11 was the dominant clone.Phylogenetic analysis revealed three major clades including the top one of Clade 3 for CG258 cpKP isolates.Additionally,carbapenemase gene analysis indicated that blaKPC was dominant in the cpKP isolates,and most blaKPC genes were located in five major incompatibility(Inc)groups of blaKPC-harboring plasmids.Importantly,three advantageous combinations of host–blaKPC-carrying plasmid(Clade 3.1+3.2–IncFIIpHN7A8,Clade 3.1+3.2–IncFIIpHN7A8:IncR,and Clade 3.3–IncFIIpHN7A8:IncpA1763-KPC)were identified to confer cpKP isolates the advantages in both genotypes(strong correlation/coevolution)and phenotypes(resistance/growth/competition)to facilitate the nationwide spread of ST11/CG258 cpKP.Intriguingly,Bayesian skyline analysis illustrated that the three advantageous combinations might be directly associated with the strong population expansion during 2007–2008 and subsequent maintenance of the population of ST11/CG258 cpKP after 2008.We then examined drug resistance profiles of these cpKP isolates and proposed combination treatment regimens for CG258/non-CG258 cpKP infections.Thus,the findings of our systematical analysis shed light on the molecular epidemiology and genetic basis for the dissemination of ST11/CG258 cpKP in China,and much emphasis should be given to the close monitoring of advantageous cpKP–plasmid combinations.展开更多
Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins ...Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins and other factors involved in various biological processes,includingβ-lactamase and antibiotic-resistance genes.This study aimed to reveal the transmission mechanism of OMV-mediated drug resistance of Klebsiella(K.)pneumoniae.Methods We selected CR-KP producing K.pneumoniae carbapenemase-2(KPC-2)to study whether they can transfer resistance genes through OMVs.The OMVs of CR-KP were obtained by ultracentrifugation,and incubated with carbapenem-sensitive K.pneumoniae for 4 h.Finally,the carbapenem-sensitive K.pneumoniae was tested for the presence of bla_(KPC-2)resistance gene and its sensitivity to carbapenem antibiotics.Results The existence of OMVs was observed by the electron microscopy.The extracted OMVs had bla_(KPC-2)resistance gene.After incubation with OMVs,bla_(KPC-2)resistance gene was detected in sensitive K.pneumoniae,and it became resistant to imipenem and meropenem.Conclusion This study demonstrated that OMVs isolated from KPC-2-producing CR-KP could deliver bla_(KPC-2)to sensitive K.pneumoniae,allowing the bacteria to produce carbapenemase,which may provide a novel target for innovative therapies in combination with conventional antibiotics for treating carbapenem-resistant Enterobacteriaceae.展开更多
Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years.Here,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal sam...Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years.Here,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal samples and the environment of a duck farm in China.Four bla_(IMI)-positive Enterobacter isolates were resistant to carbapenem and colistin.Three bla_(IMI) subtypes were detected in different molecular categories of Enterobacter.The detection of the various IMI producers highlights the diversity of carbapenemases in a duck farm.Whole-genome sequencing demonstrated the bla_(IMI) genes were present in chromosomes or plasmids in these strains.The conjugation experiment demonstrated the ability of bla_(IMI)-carrying plasmid to transmit horizontally.The molecular evolution characteristics were examined through comparative genetic analysis.The study demonstrated the presence of chromosomal and plasmid bla_(IMI) and the bla_(IMI)-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli C600.The similar genetic content was discovered between two bla_(IMI-16)-positive Enterobacter asburiae.In addition,a bla_(IMI-16)-carrying plasmid is an IncFII(Yp)plasmid,and a substantial amount of mobile genetic elements were identified around bla_(IMI-16).The IS-like elements and IncFII(Yp)plasmid are significant in the propagation of bla_(IMI).Our study provides evidence for the transmission of diverse bla_(IMI) genes in China and supplies additional reference data for bla_(IMI)-positive antimicrobialresistant Enterobacter.Routine surveys of bla_(IMI)-positive Enterobacter from animal-raising environments must be given more focus.展开更多
We aimed to characterize NDM-5-producing Enterobacteriaceae from aquatic products in Guangzhou,China.A total of 196 intestinal samples of grass carp collected in 2019 were screened for carbapenemase genes.Characteriza...We aimed to characterize NDM-5-producing Enterobacteriaceae from aquatic products in Guangzhou,China.A total of 196 intestinal samples of grass carp collected in 2019 were screened for carbapenemase genes.Characterization of bla_(NDM-5) positive isolates and plasmids was determined by antimicrobial susceptibility testing,conjugation experiments,Illumina HiSeq,and Nanopore sequencing.One Citrobacter freundii and six Escherichia coli strains recovered from seven intestinal samples were verified as bla_(NDM-5) carriers(3.57%,7/196).The bla_(NDM-5) genes were located on the lncX3(n=5),lncHI2(n=1),or lncHI2-lncF(n=1)plasmids.All bla_(NDM-5)-bearing plasmids were transferred by conjugation at frequencies of~10^(-4)-10^(-6).Based on sequence analysis,the lncHI2 plasmid pHNBYF33-1 was similar to other bla_(NDM-5)-carrying lncHI2 plasmids deposited in GenBank from Guangdong ducks.In all lncHI2 plasmids,bla_(NDM-5)was embedded in a novel transposon,Tn7057(IS3000-△ISAba125-IS5-△ISAba125-bla_(NDM-5)-bleMBL-trpF-tat-△dct-IS26-△umuD-△ISKox3-IS3000),which was identical to the genetic structure surrounding bla_(NDM-5)found in some IncX3 plasmids.The lncHI2-lncF hybrid plasmid pHNTH9F11-1 was formed by homologous recombination of the bla_(NDM-5)-carrying lncHI2 plasmid and a heavy-metal-resistant IncF plasmid through△Tn1721 To the best of our knowledge,this is the first report on the characterization of bla_(NDM-5)-bearing plasmids in fish in China.The lncHI2 plasmid pHNBYF33-1 may be transmitted from ducks,considering the common duck-fish freshwater aquaculture system in Guangdong.Tn7051 is likely responsible for the transfer of bla_(NDM-5) from lncX3 to lncHI2 plasmids in Enterobacteriaceae,resulting in the expansion of transmission vectors of bla_(NDM-5).展开更多
Background: Klebsiella pneumoniae is one of the most frequent opportunistic pathogens causing a range of infections and being resistant for beta-lactamases (ESBL) and Carbapenemases. Aim: The aim of the present study ...Background: Klebsiella pneumoniae is one of the most frequent opportunistic pathogens causing a range of infections and being resistant for beta-lactamases (ESBL) and Carbapenemases. Aim: The aim of the present study was to determine the antimicrobial resistance patterns and molecular characterization establishing the phenotypes and genotypes associated with drug resistance, an antibiogram of genotypically positive isolates for resistance of Klebsiella pneumoniae in clinical isolates at MRRH. Materials and Methods: A laboratory-based descriptive cross-sectional study that was conducted from September 2018 to May 2019 at MRRH. Klebsiella pneumoniae was identified by cultural and biochemical methods. Antibiotic sensitivity test was performed by modified Kirby-Bauer disc diffusion technique. ESBL production in Klebsiella pneumoniae was tested by double-disc synergy test, Carbapenemase production by MHT, Boronic Acid or EDTA test using Meropenem phenotypically and both resistance confirmed genotypically by Multiplex PCR. Results: Out of 1055 clinical isolates, 298 (28.2%) were found positive for Klebsiella.spp, 175 isolates were subcultured among which 22 (12.57%) were K. pneumoniae based on API 20E. Overall Sensitivity patterns of these Klebsiella pneumoniae isolates to Ceftriaxone, (Amoxicillin/Clavulanate), Gentamicin, Cefepime, Ciprofloxacin, Cefoxitin, Nitrofurantoin, Cefuroxime, piperacillin/tazobactam, Meropenem, Ceftazidime and cefotaxime were 72.7%, 63.7%, 54.5%, 45.5%, 31.8%, 31.8%, 27.3%, 27.3%, 22.7%, 22.7%, 18.2%, 9.1%, 9.1% respectively. ESBL producing K. pneumoniae was found at 68.18% (15/22) phenotypically. Genotypically;the ESBL genes were blaCTX-M (100%), blaSHV (80%) and blaTEM (100;47%);8/15 (73.3%) had CTX-M, SHV, TEM, 4/15 (26.67%) CTX-M, TEM, 3/15 (20.00%) CTX-M and SHV. Carbapenemase producing K. pneumoniae was found at 31.82% (7/22) phenotypically;1/7 (14.28%) by MHT, 4/7 (57.14%) Boronic acid test and 2/7 (28.58%) EDTA test. Genotypically;3/4 [(75%) 42.86%] had OXA-48, 1/4 [(25%) 14.28%] OXA-48 and KPC gene, 1/2 [(50%) 14.28%] KPC and VIM, 1/2 [(50%) 14.28%] KPC and KPC gene [(100%) 14.28%]. Conclusion/Recommendations: DDS to be used for ESBL production, MHT, Boronic Acid test and EDTA tests using Meropenem/or Imipenem for Carbapenemase-production routinely.展开更多
Objective:The aim of this study is to detect in vitro the synergetic activity of colistin in combination with imipenem,amikacin or ciprofloxacin,at sub-inhibitory concentrations,against carbapenems-resistant(CR)Acinet...Objective:The aim of this study is to detect in vitro the synergetic activity of colistin in combination with imipenem,amikacin or ciprofloxacin,at sub-inhibitory concentrations,against carbapenems-resistant(CR)Acinetobacter baumannii and Pseudomonas aeruginosa strains isolated from various wards in Annaba teaching hospital in eastern Algeria.Materials and Methods:The minimal inhibitory concentrations(MIC)were determined by broth macrodilution(BMD).Carbapenemase encoding genes were screened using polymerase chain reaction(PCR).The activity of colistin in combination with second antibiotic was evaluated by the Checkerboard Technique.Results:39 CR P.aeruginosa and 21 CR A.baumanni strains where collected.The MIC values ranging from(0.25 to 4μg/ml)to colistin,≥16μg/ml for imipenem,≥4μg/ml to amikacin and≥8μg/ml ciprofloxacin.The PCR reveals the presence of the genes blaOXA23(n=12),blaOXA24(n=6),blaNDM1(n=3)in A.baumannii and blaVIM2(n=12)in P.aeruginosa.The combination of colistin with imipenem showed synergistic effect on 57.14%and 46.15%of A.baumannii and P.aeruginosa isolates,respectively.For colistin and amikacin,the synergistic effect is detected in 28.6%of A.baumannii and 30.8%of P.aeruginosa.While colistin and ciprofloxacin showed synergy on 14.29%and 15.38%of A.baumannii and P.aeruginosa isolates,respectively.Conclusion:CR A.baumannii and P.aeruginosa remain the most prevalent infection agents in patients from high-risk wards at Annaba Hospital.Colistin associated with imipenem or with amikacin at sub-inhibitory concentrations gives very encouraging results allowing better management of infections caused by this type of bacteria.展开更多
文摘Background: Carbapenemase-producing Enterobacteriaceae (CPE) are an important and increasing threat to global health. They are nowadays more encountered routinely in hospitals and cause high morbidity and mortality due to limited therapeutic alternatives. This study sought to determine the prevalence of CPE in Yaoundé teaching hospital, Cameroon, and the associated risk factors. Materials and Method: To achieve this goal, a descriptive cross-sectional study coupled to an analytical component with consecutive collection of Enterobacteria strains was carried out during a three-month period (from 27<sup>th</sup> July to 24<sup>th</sup> October 2018) in the University Teaching Hospital of Yaoundé, Cameroon. The oxidase and biochemical identification tests using a miniaturized Api 20 E system were performed on colonies grown on Eosin Methylene Blue (EMB) medium and subcultured on nutrient agar. Drug susceptibility testing was carried out according to the Antibiogram Committee of the French Society of Microbiology (CA-SFM 2018.V.2.0). The detection of carbapenemase production was performed by the CA-SFM 2018 algorithm for the screening of carbapenemase-producing enterobacteriaceae and its classification by inhibitory synergy tests. Results: Out of the 104 isolates, Escherichia coli (50%) was the most prevalent species, followed by Klebsiella pneumoniae (37.5%) and Citrobacter frendii (12.5%). Drugs susceptibility patterns showed a high resistance to penicillins group (97.4% to amoxicillin), cephalosporins (68.4% to cefotaxim, 58.1% to cefixim, 60.7% to ceftazidim, 57.1% of cefoxitin) and aztreonam (55.7%). However, 11.9% carbapenems related resistance was noticed: 14.4% to imipenem, 13.8% to ertapenem and 7.5% to meropenem. Numerous co-resistance to quinolones (65.8%), fluoroquinolones (49.6%), aminoglycosides (49.6%) and cotrimoxazole (71.8%) were also observed. From 104 isolates, AmpC production represented 23.08% (25/104) and 36.54% (38/104) were ESBL-isolates. The overall prevalence of CPE was 25% (26/104) with K.pneumoniae predominant (61.53%). Besides, Class A and class B carbapenemase were mainly produced with respectively 20% (21/104) and 5% (5/104). Univariate analysis revealed a significant association of carbapenemase production to Klebsiella pneumoniae (p = 0.01), ESBL and AmpC production ((P = 0.01 and P = 0.001 respectively) while that association was only significant to Klebsiella spp (p = 0.04) and AmpC production (p = 0.02) in multivariate analysis. Conclusion: The multi-resistance of Enterobacteriaceae to antibiotics in Cameroon has considerably increased. More attention should be paid to those bacteria to stall antimicrobial resistance spread.
文摘Background and Purpose: The reintroduction of colistin as a last resort treatment against multi-resistant Gram-negative bacilli, is currently challenged by the emergence of colistin-resistant bacteria. The aim of this study was to assess the susceptibility of Pseudomonas and Acinetobacter strains to colistin, to identify carbapenemase production, and to investigate the plasmid genes involved in colistin resistance and carbapenemase production. Methodology: In order to establish the susceptibility profiles of 17 strains of Pseudomonas and Acinetobacter to colistin, their Minimum Inhibitory Concentrations (MICs) were determined using the liquid microdilution method. The possible production of carbapenemases was investigated with the modified Carbapenem Inactivation Method (mCIM). The search for genes encoding carbapenemases (bla<sub>OXA</sub>, bla<sub>IMP</sub>, bla<sub>Carba</sub>) and those responsible for plasmid resistance to colistin (mcr-1 and mcr-2) was performed by conventional PCR. Results and Conclusion: Ninety-four percent (94%) (16/17) of the strains were resistant to colistin. Intraspecies distribution was 50% (8/16), 31% (5/16), 13% (2/16) and 6% (1/16) for Acinetobacter baumannii, Pseudomonas aeruginosa, Pseudomonas luteola, and Pseudomonas fluorescens, respectively. Twenty-nine percent (29%) (6/17) of the strains produced carbapenemases. No mcr-1 and mcr-2 plasmid genes were detected. On the other hand, 17.6% (3/17) of the strains possessed the carbapenemase genes distributed as follows: Carba type (60%), OXA type (40%) and IMP type (0%). The results of this study highlight a high resistance to colistin in strains belonging to the genera Acinetobacter and Pseudomonas, and some of these strains produce carbapenemases.
文摘Background and Objective: Nowadays, the clinical utility of carbapenems is threatened by the emergence of resistant bacteria, favored by its increasing use. According to the WHO, Acinetobacter baumannii: nosocomial infection agent, tops the list of priority antibiotic-resistant pathogens, considered to be the riskiest for humans. This study sought to determine the prevalence of carbapenemase-producing Acinetobacter baumannii strains in four health facilities in the Center and Littoral regions of Cameroon and the associated risk factors. Materials and Method: An analytical cross-sectional study was conducted over a six-month period from January to June 2022. All suspicious A. baumanii isolates obtained from pathological samples at the bacteriology laboratory of the different health facilities were systematically collected and re-identified. Re-identification and antimicrobial susceptibility Testing (AST) were performed using the VITEK 2 System and the Kirby-Bauer method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Detection and phenotypic characterization of carbapenemases was performed according to adequate standard procedures. Results: A total of 168/226 clinical isolates of Acinetobacter baumannii were confirmed after re-identification, among which 52.69% derived from male patients, 55.09% from participants aged between 10 - 39 years old, and 46.71% from pus samples. A very high resistance rates to all families of antibiotics was noted, except to colistin (10.2%). 40.12% of these isolates produced carbapenemase, represented by 62.69% of class B and 37.31% of class A. Carbapenemase production was observed only at HMR1, Centre region and at Laquintinie hospital, Littoral region with 53.33% and 50% respectively, even if there is no significant difference (P = 0.81). In addition, frequent hospitalisation was significantly associated to the production of carbapenemase among A. baumanii (Adjusted-OR = 16.53, P-value 0.0001). Conclusion: This study highlighted the emergence of carbapenemase-producing Acinetobacter baumannii which is increasingly growing. Continuous drug-resistant monitoring and preventive measures could help to prevent and curb the dissemination of A. baumanii resistance genes, especially in health settings.
基金the financial support of the National Key Research and Development Program of China (2017YFC1200203 and 2016YFD0501105)the Mega-projects of Science Research of China (2018ZX10733402-004 and 2018ZX10712001-005)+2 种基金the National Natural Science Foundation of China (81741098 and 81711530049)the Zhejiang Provincial Key Research and Development Program (2015C03032)the Zhejiang Provincial Natural Science Foundation of China (LY17H190003)
文摘Carbapenemase-producing Enterobacteriaceae(CPE) isolates are recognized as one of the most severe threats to public health. However, the population structure and genetic characteristics of CPE isolates among bloodstream infections(BSIs) are largely unknown. To address this knowledge gap, in this study,we included patients with clinically significant BSIs due to Enterobacterales isolates, recruited from 26 sentinel hospitals in China(2014–2015). CPE isolates were microbiologically and genomically characterized,including their susceptibility profiles, molecular typing, phylogenetic features, and genetic context analysis of carbapenemase-encoding genes. Of the 2569 BSI Enterobacterales isolates enrolled, 42(1.6%) were carbapenemase-positive. Moreover, among the 2242 investigated isolates, 1111(49.6%) extendedspectrum β-lactamase(ESBL)-producing isolates were identified in Escherichia coli(E. coli), Klebsiella pneumoniae(K. pneumoniae), Proteus mirabilis(P. mirabilis), and Klebsiella oxytoca. Whole genome sequencing analysis showed the clonal spread of K. pneumoniae carbapenemase(KPC)-2-producing K. pneumoniae sequence type(ST) 11 and New Delhi metallo-β-lactamase(NDM)-5-producing E. coli ST167 in our collection. Plasmid analysis revealed that carbapenemase-encoding genes were located on multiple plasmids. A high prevalence of biofilm-encoding type 3 fimbriae clusters and yesiniabactin-associated genes was observed in K. pneumoniae isolates. This work demonstrates the high prevalence of ESBLs and the wide dissemination of CPE among BSI isolates in China, which represent real clinical threats. Moreover, our findings first illustrate a more comprehensive genome scenario of CPE isolates among BSIs. The clonal spread of KPC-2-producing K. pneumoniae ST11 and NDM-5-producing E. coli ST167 needs to be closely monitored.
基金supported by grants from National Fund for the Research and National Agency for the Development of Research in Health(Algeria)
文摘Objective:To assess and characterize antibiotic resistance in Acinetobacter baumannii strains recovered from 5 health-care facilities in Algiers.Methods:Antibiotic susceptibility testing was performed by agar diffusion and agar dilution methods,resistance genes were identified by PCR and sequencing,and molecular typing of isolates was carried out by enterobacterial repetitive intergenic consensus-PCR(ERIC-PCR).Results:Among 125 tested isolates,117(93.6% ) were multidrug-resistant.of which 94(75.2% ) were imipenem resistant.The bla_(ADC)and bla_(OXA-51-like) genes were detected in all isolates,in association with ISAba I sequence in 84% and 8% (imipenem resistant) of isolates,respectively.The bla_(OXA-23-like) and bla_(OXA-24-like)carbapenemase genes were delected in 67.02% and 20.21% of imipenem-resistant isolates,respectively.The bla_(OXA-23-like) gene is linked to ISAba1 or ISAba4 elements.The metallo-β-lactamase NDM-1 gene was found in 10(10.6% ) imipenem-resisianl strains from three hospitals,it is linked to ISAba125 clement in nine strains.Extended spectrum β-lactamases production was not detected.Imipenem and cefotaxime resistance phenolypes could not be transferred to Escherichia coli by conjugation.Outer membrane protein CarO gene was not delected in four imipenem-resisianl isolates.The aac(6')-1b.sul1,sul2,tetA and tetB genes were present in 5.31% .36.17% .77.65% .1.06% and 65.92% of strains,respectively.Class 1 integrons were detected in 23.4% strains.KRIC-PCR typing showed a genetic diversity among bla_(OXA-23-like) and bla_(OXA-24-like) positive strains,while clonality was observed among bla_(NDM-1)positives.Conclusions:This study highlighted the high prevalence of imipenem resistance in Acinetobacter baumannii in Algiers hospitals mediated mainly by bla_(OXA-23-like),bla_(OXA-24-like),and bla_(NDM-1) genes.
文摘<b>Background:</b> The increasing resistance of bacteria to various antibiotics is a worldwide public health issue. Carbapenems that have elicited great hope in treating infections caused by multidrug-resistant germs have seen their efficacy narrowed over time with the emergence of other novel resistance mechanisms, notably the production of Carbapenemases. <b>Methods:</b> A prospective cross-sectional study was conducted from May 2017 to May 2018 in Douala (Cameroon) to detect carbapenemase-producing Gram-negative bacilli. Isolated strains were identified using the Vitek2<sup>TM</sup> system. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method on agar plates with 20 selected commercially available antibiotic discs. The bacterial strains were tested for the production of three Carbapenemases (OXA-48, NDM, KPC), using an immuno-chromatographic technique, with the “RESIST-3 O.K.N. K-SeT” rapid detection kit. <b>Results:</b> During the study period, 1687 strains of Gram-negative bacilli were isolated in selected laboratories with a total of 200 multi-resistant strains identified (11.9%). Among the multi-resistant strains, <i>E. coli</i> was the species most represented in <i>Enterobacteriaceae</i> (27.5%) followed by <i>K. pneumoniae</i> (15.5%) and the non-fermenting Gram-negative bacilli were predominantly <i>P. aeruginosa</i> (20.5%). These strains mainly came from urine and pus, <i>i.e.</i> 41% and 32% respectively. Thirty-two (16%) strains produced one of the Carbapenemases with a higher frequency at the General Hospital (84%). NDM-type carbapenemase was the most frequently identified (8.5%), OXA-48 type 7.5%, and no KPC production was observed. Among the <i>Enterobacteriaceae</i> 22.9% produced Carbapenemases and only 5.1% of the non-fermenting bacilli produced these enzymes. The isolates strains were completely resistant to all antibiotics except Amikacin and Fosfomycin. The strains producing the NDM-type carbapenemase showed higher rates of resistance to almost all of the antibiotics tested. <b>Conclusion:</b> Multidrug-resistant strains are experiencing an increase in evolution. The apparition of strains producing Carbapenemases prominently, the NDM and OXA-48 favor this increase. The activities of antibiotics with high efficacies on these strains are low.
基金grants from the National Basic Research Program of China(2013CB127200)the National Natural Science Foundation of China(31422055).
文摘In recent years,the mobile metallo-β-lactamase(MBL)genes have been found to correspond to one of the most important resistance characters identified in Gramnegative bacteria,severely affecting clinical chemotherapy and threatening public health.The prevalence of mobile MBL genes and their flanking regions in Gram-negative bacteria from diseased pigs in China was investigated.A total of 334 lung samples from diseased pigs were screened for Gram-negative bacteria classified as non-susceptible to meropenem(MIC≥4mg·L^(–1)).Six isolates,including three Escherichia coli,two Acinetobacter baumanii and one A.calcoaeticus,exhibitedMBL production and carried the blaNDM-1 gene.S1-PFGE and Southern blot analysis showed that the blaNDM-1 gene was located on the chromosome of one A.baumanii isolate and on plasmids of various sizes in the other five isolates.MIC testing using broth microdilution revealed that all blaNDM-1-carrying isolates and some of their transconjugants exhibited resistance to almost allβ-lactams tested.Whole genome sequencing revealed that the flanking region of the blaNDM-1 gene from all porcine isolates had high levels of similarity with the corresponding regions in human isolates.One porcine E.coli isolate carrying blaNDM-1 was typed as ST48,a common sequence type in human E.coli isolates.These results suggest the possibility of human-tofood animal transfer of blaNDM-1-producing E.coli,highlighting the need for surveillance of carbapenemase producers among bacteria from food animals.In addition,the prudent use of antimicrobial agents to decrease the opportunities for co-selection of carbapenemase genes in food animals is also urgently needed.
基金supported by the National Natural Science Foundation of China(Grant No.31770870)the National Science and Technology Major Projects of China(Grant No.2018ZX10302-301-004-003).
文摘The rapid spread of carbapenemase-producing Klebsiella pneumoniae(cpKP)poses serious threats to public health;however,the underlying genetic basis for its dissemination is still unknown.We conducted a comprehensive genomic epidemiology analysis on 420 cpKP isolates collected from 70 hospitals in 24 provinces/autonomous regions/municipalities of China during 2009–2017 by short-/long-read sequencing.The results showed that most cpKP isolates were categorized into clonal group 258(CG258),in which ST11 was the dominant clone.Phylogenetic analysis revealed three major clades including the top one of Clade 3 for CG258 cpKP isolates.Additionally,carbapenemase gene analysis indicated that blaKPC was dominant in the cpKP isolates,and most blaKPC genes were located in five major incompatibility(Inc)groups of blaKPC-harboring plasmids.Importantly,three advantageous combinations of host–blaKPC-carrying plasmid(Clade 3.1+3.2–IncFIIpHN7A8,Clade 3.1+3.2–IncFIIpHN7A8:IncR,and Clade 3.3–IncFIIpHN7A8:IncpA1763-KPC)were identified to confer cpKP isolates the advantages in both genotypes(strong correlation/coevolution)and phenotypes(resistance/growth/competition)to facilitate the nationwide spread of ST11/CG258 cpKP.Intriguingly,Bayesian skyline analysis illustrated that the three advantageous combinations might be directly associated with the strong population expansion during 2007–2008 and subsequent maintenance of the population of ST11/CG258 cpKP after 2008.We then examined drug resistance profiles of these cpKP isolates and proposed combination treatment regimens for CG258/non-CG258 cpKP infections.Thus,the findings of our systematical analysis shed light on the molecular epidemiology and genetic basis for the dissemination of ST11/CG258 cpKP in China,and much emphasis should be given to the close monitoring of advantageous cpKP–plasmid combinations.
基金supported by the National Natural Science Foundation of China(No.31771189)the Wuhan Health Commission(No.WX18C17 and No.WX19Q31)the Natural Science Foundation of Hubei Province,China(No.2017CFA065 and No.WJ2019H378).
文摘Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins and other factors involved in various biological processes,includingβ-lactamase and antibiotic-resistance genes.This study aimed to reveal the transmission mechanism of OMV-mediated drug resistance of Klebsiella(K.)pneumoniae.Methods We selected CR-KP producing K.pneumoniae carbapenemase-2(KPC-2)to study whether they can transfer resistance genes through OMVs.The OMVs of CR-KP were obtained by ultracentrifugation,and incubated with carbapenem-sensitive K.pneumoniae for 4 h.Finally,the carbapenem-sensitive K.pneumoniae was tested for the presence of bla_(KPC-2)resistance gene and its sensitivity to carbapenem antibiotics.Results The existence of OMVs was observed by the electron microscopy.The extracted OMVs had bla_(KPC-2)resistance gene.After incubation with OMVs,bla_(KPC-2)resistance gene was detected in sensitive K.pneumoniae,and it became resistant to imipenem and meropenem.Conclusion This study demonstrated that OMVs isolated from KPC-2-producing CR-KP could deliver bla_(KPC-2)to sensitive K.pneumoniae,allowing the bacteria to produce carbapenemase,which may provide a novel target for innovative therapies in combination with conventional antibiotics for treating carbapenem-resistant Enterobacteriaceae.
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(32121004)。
文摘Carbapenem-and colistin-resistant Enterobacter has been a clinical and therapy problem in recent years.Here,we report the carbapenem-and colistin-resistant Enterobacter harboring bla_(IMI) isolated from intestinal samples and the environment of a duck farm in China.Four bla_(IMI)-positive Enterobacter isolates were resistant to carbapenem and colistin.Three bla_(IMI) subtypes were detected in different molecular categories of Enterobacter.The detection of the various IMI producers highlights the diversity of carbapenemases in a duck farm.Whole-genome sequencing demonstrated the bla_(IMI) genes were present in chromosomes or plasmids in these strains.The conjugation experiment demonstrated the ability of bla_(IMI)-carrying plasmid to transmit horizontally.The molecular evolution characteristics were examined through comparative genetic analysis.The study demonstrated the presence of chromosomal and plasmid bla_(IMI) and the bla_(IMI)-carrying plasmid exhibits a horizontal transmission between Enterobacter and Escherichia coli C600.The similar genetic content was discovered between two bla_(IMI-16)-positive Enterobacter asburiae.In addition,a bla_(IMI-16)-carrying plasmid is an IncFII(Yp)plasmid,and a substantial amount of mobile genetic elements were identified around bla_(IMI-16).The IS-like elements and IncFII(Yp)plasmid are significant in the propagation of bla_(IMI).Our study provides evidence for the transmission of diverse bla_(IMI) genes in China and supplies additional reference data for bla_(IMI)-positive antimicrobialresistant Enterobacter.Routine surveys of bla_(IMI)-positive Enterobacter from animal-raising environments must be given more focus.
基金supported by the National Natural Science Foundation of China(31625026,32141002)Innovation Team Project of Guangdong University(2019KCXTD001)。
文摘We aimed to characterize NDM-5-producing Enterobacteriaceae from aquatic products in Guangzhou,China.A total of 196 intestinal samples of grass carp collected in 2019 were screened for carbapenemase genes.Characterization of bla_(NDM-5) positive isolates and plasmids was determined by antimicrobial susceptibility testing,conjugation experiments,Illumina HiSeq,and Nanopore sequencing.One Citrobacter freundii and six Escherichia coli strains recovered from seven intestinal samples were verified as bla_(NDM-5) carriers(3.57%,7/196).The bla_(NDM-5) genes were located on the lncX3(n=5),lncHI2(n=1),or lncHI2-lncF(n=1)plasmids.All bla_(NDM-5)-bearing plasmids were transferred by conjugation at frequencies of~10^(-4)-10^(-6).Based on sequence analysis,the lncHI2 plasmid pHNBYF33-1 was similar to other bla_(NDM-5)-carrying lncHI2 plasmids deposited in GenBank from Guangdong ducks.In all lncHI2 plasmids,bla_(NDM-5)was embedded in a novel transposon,Tn7057(IS3000-△ISAba125-IS5-△ISAba125-bla_(NDM-5)-bleMBL-trpF-tat-△dct-IS26-△umuD-△ISKox3-IS3000),which was identical to the genetic structure surrounding bla_(NDM-5)found in some IncX3 plasmids.The lncHI2-lncF hybrid plasmid pHNTH9F11-1 was formed by homologous recombination of the bla_(NDM-5)-carrying lncHI2 plasmid and a heavy-metal-resistant IncF plasmid through△Tn1721 To the best of our knowledge,this is the first report on the characterization of bla_(NDM-5)-bearing plasmids in fish in China.The lncHI2 plasmid pHNBYF33-1 may be transmitted from ducks,considering the common duck-fish freshwater aquaculture system in Guangdong.Tn7051 is likely responsible for the transfer of bla_(NDM-5) from lncX3 to lncHI2 plasmids in Enterobacteriaceae,resulting in the expansion of transmission vectors of bla_(NDM-5).
文摘Background: Klebsiella pneumoniae is one of the most frequent opportunistic pathogens causing a range of infections and being resistant for beta-lactamases (ESBL) and Carbapenemases. Aim: The aim of the present study was to determine the antimicrobial resistance patterns and molecular characterization establishing the phenotypes and genotypes associated with drug resistance, an antibiogram of genotypically positive isolates for resistance of Klebsiella pneumoniae in clinical isolates at MRRH. Materials and Methods: A laboratory-based descriptive cross-sectional study that was conducted from September 2018 to May 2019 at MRRH. Klebsiella pneumoniae was identified by cultural and biochemical methods. Antibiotic sensitivity test was performed by modified Kirby-Bauer disc diffusion technique. ESBL production in Klebsiella pneumoniae was tested by double-disc synergy test, Carbapenemase production by MHT, Boronic Acid or EDTA test using Meropenem phenotypically and both resistance confirmed genotypically by Multiplex PCR. Results: Out of 1055 clinical isolates, 298 (28.2%) were found positive for Klebsiella.spp, 175 isolates were subcultured among which 22 (12.57%) were K. pneumoniae based on API 20E. Overall Sensitivity patterns of these Klebsiella pneumoniae isolates to Ceftriaxone, (Amoxicillin/Clavulanate), Gentamicin, Cefepime, Ciprofloxacin, Cefoxitin, Nitrofurantoin, Cefuroxime, piperacillin/tazobactam, Meropenem, Ceftazidime and cefotaxime were 72.7%, 63.7%, 54.5%, 45.5%, 31.8%, 31.8%, 27.3%, 27.3%, 22.7%, 22.7%, 18.2%, 9.1%, 9.1% respectively. ESBL producing K. pneumoniae was found at 68.18% (15/22) phenotypically. Genotypically;the ESBL genes were blaCTX-M (100%), blaSHV (80%) and blaTEM (100;47%);8/15 (73.3%) had CTX-M, SHV, TEM, 4/15 (26.67%) CTX-M, TEM, 3/15 (20.00%) CTX-M and SHV. Carbapenemase producing K. pneumoniae was found at 31.82% (7/22) phenotypically;1/7 (14.28%) by MHT, 4/7 (57.14%) Boronic acid test and 2/7 (28.58%) EDTA test. Genotypically;3/4 [(75%) 42.86%] had OXA-48, 1/4 [(25%) 14.28%] OXA-48 and KPC gene, 1/2 [(50%) 14.28%] KPC and VIM, 1/2 [(50%) 14.28%] KPC and KPC gene [(100%) 14.28%]. Conclusion/Recommendations: DDS to be used for ESBL production, MHT, Boronic Acid test and EDTA tests using Meropenem/or Imipenem for Carbapenemase-production routinely.
文摘Objective:The aim of this study is to detect in vitro the synergetic activity of colistin in combination with imipenem,amikacin or ciprofloxacin,at sub-inhibitory concentrations,against carbapenems-resistant(CR)Acinetobacter baumannii and Pseudomonas aeruginosa strains isolated from various wards in Annaba teaching hospital in eastern Algeria.Materials and Methods:The minimal inhibitory concentrations(MIC)were determined by broth macrodilution(BMD).Carbapenemase encoding genes were screened using polymerase chain reaction(PCR).The activity of colistin in combination with second antibiotic was evaluated by the Checkerboard Technique.Results:39 CR P.aeruginosa and 21 CR A.baumanni strains where collected.The MIC values ranging from(0.25 to 4μg/ml)to colistin,≥16μg/ml for imipenem,≥4μg/ml to amikacin and≥8μg/ml ciprofloxacin.The PCR reveals the presence of the genes blaOXA23(n=12),blaOXA24(n=6),blaNDM1(n=3)in A.baumannii and blaVIM2(n=12)in P.aeruginosa.The combination of colistin with imipenem showed synergistic effect on 57.14%and 46.15%of A.baumannii and P.aeruginosa isolates,respectively.For colistin and amikacin,the synergistic effect is detected in 28.6%of A.baumannii and 30.8%of P.aeruginosa.While colistin and ciprofloxacin showed synergy on 14.29%and 15.38%of A.baumannii and P.aeruginosa isolates,respectively.Conclusion:CR A.baumannii and P.aeruginosa remain the most prevalent infection agents in patients from high-risk wards at Annaba Hospital.Colistin associated with imipenem or with amikacin at sub-inhibitory concentrations gives very encouraging results allowing better management of infections caused by this type of bacteria.
