Quinolone Susceptibility and Detection of qnr and aac(6')-Ib-cr Genes in Community Isolates of Klebsiella pneumoniae. - Related Documents




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110901.0000Quinolone Susceptibility and Detection of qnr and aac(6')-Ib-cr Genes in Community Isolates of Klebsiella pneumoniae. BACKGROUND: Plasmid-mediated quinolone resistance genes (PMQR) have been shown to play not only an important role in quinolone resistance, but also resistance to other antibiotics, particularly β-lactams and aminoglycosides. These genes are mainly associated with clinical isolates of Enterobacteriaceae. However, detection of PMQR genes in the community isolates can increase the dissemination rate of resistance determinants among bacteria. OBJECTIVES: This study aimed to investigate quinolone resistance and distribution of qnr and aac (6')-Ib-cr genes among the community isolates of Klebsiella pneumoniae. MATERIALS AND METHODS: Fifty-two K. pneumoniae isolates were collected from the Central Laboratory in Karaj between July 2010 and January 2011. Antibacterial susceptibility was determined by the disc diffusion method. Quinolone and/or cephalosporin-resistant isolates were screened for the presence of qnrA, qnrB, qnrS and aac (6')-Ib-cr genes by polymerase chain reaction (PCR). RESULTS: Of the 52 K. pneumoniae isolates, 23 were resistant to cephalosporins and/or quinolones. Overall, 7 out of the 23 resistant isolates harbored qnr and/or aac (6')-Ib-cr genes (30.4%). Among these, 5 isolates were resistant to both classes of antibiotics of which; 3 carried the aac (6')-Ib-cr gene, one had the qnrS, and one harbored both aac (6')-Ib-cr and qnrB genes. None of the isolates contained qnrA. Two isolates were sensitive to quinolones and resistant to cephalosporins of which; one had qnrS and the other carried the aac (6')-Ib-cr gene. CONCLUSIONS: Our study showed that 30.4% of the quinolone and/or cephalosporin resistant community isolates of K. pneumoniae carried PMQR genes. These results confirm that community isolates can be an important source for spreading antibiotic resistance determinants among Gram negative pathogens. This is the first report from Iran on detection of PMQR in the community isolates of K. pneumoniae.201425368793
110810.9999Resistance Mechanism of Carbapenem-Resistant Enterobacteriaceae to Quinolones. BACKGROUND: To investigate the epidemics of plasmid-mediated quinolone resistance (PMQR) gene in carbapenem-resistant Enterobacteriaceae (CRE) and the resistance mechanism. METHODS: We collected CRE bacteria isolated clinically between December 2017 and December 2018 for identification and drug sensitivity testing using a VITEK2 Compact Analyzer. Furthermore, genes, including qnrA, qnrB, qnrS, qepA, and acc (6') Ib-cr, were determined through the polymerase chain reaction and sequencing. The hori-zontal transfer of PMQR gene was validated through the plasmid conjugational test. RESULTS: Drug resistance rate of carbapenem-resistant Escherichia coli against quinolones was 100%, while the rate of carbapenem-resistant Klebsiella pneumoniae ranged from 15.56% to 33.33%. The detection rate of acc (6') Ib-cr was the highest (87.72%), followed by qnrB (77.19%) and qnrS (17.54%). Additionally, there were two bacteria carrying the qnrA gene (3.51%), but qepA gene was not isolated from the samples. In total, 84.21% of these bacteria carried 2 or 3 kinds of PMQR genes. Among 8 bacteria with successful plasmid conjugation, PMQR gene transfer was detected in all of them, but with no significant change in the minimum inhibitory concentration of quinolones. CONCLUSIONS: CRE remain sensitive to quinolones in spite of the high detection rate of PMQR gene in this hospital.202134383410
110620.9999Characteristics of ciprofloxacin-resistant Enterobacteriaceae isolates recovered from wastewater of an Algerian hospital. INTRODUCTION: Hospital effluents are a source of environmental pollution by drugs, antibiotic-resistant bacteria, and resistance genes. Quinolones, particularly ciprofloxacin, are commonly detected in these effluents, contributing to the emergence of antimicrobial resistance. The objective of this study was to characterize ciprofloxacin-resistant Enterobacteriaceae in hospital effluents. METHODOLOGY: Isolates were selected on Tergitol-7 agar supplemented with ciprofloxacin and genotyped by ERIC-PCR. Antibiotic susceptibility testing was done using the disk diffusion method, and minimum inhibitory concentrations were determined using the agar dilution method. Resistance genes, integrons, phylogenetic groups, and sequence types were identified by PCR and sequencing. RESULTS: A total of 17 ciprofloxacin-resistant isolates were characterized: Escherichia coli, Escherichia vulneris, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter freundii, and Citrobacter koseri/farmeri. Isolates presented concomitant resistance to nalidixic acid, ciprofloxacin, ofloxacin, and pefloxacin. A diversity in mutation patterns in gyrA and parC genes and new amino-acid substitutions in GyrA subunit were observed. Quinolone plasmidic resistance genes qnrB1, qnrB2, qnrB5/19, qnrS1, and aac(6')-Ib-cr were detected. Resistance to other antibiotic classes was observed. Class 1 integrons and resistance genes blaCTX-M-15, blaOXA-1, sul1, sul2, sul3, tetA, tetB, aadA1/2, aadA5, aph(3')-Ia, aac(3)II, dfrA1, dfrA5, dfrA7, and dfrA12 were detected. Bacterial tolerance to cadmium, zinc, and mercury was observed with the presence of the merA gene. E. coli isolates belonged to phylogenetic groups A, B1, and D and to sequence types ST405, ST443, ST101, ST10, and ST347. CONCLUSIONS: This study highlighted bacterial multidrug resistance linked to ciprofloxacin and, consequently, the risk of bacterial exposure to this antibiotic.201627482804
117830.9999Molecular Characterization of Plasmid-Mediated Quinolone Resistance Genes in Multidrug-Resistant Escherichia coli Isolated From Wastewater Generated From the Hospital Environment. AIM: This study investigated the carriage of Plasmid-Mediated Quinolone Resistance (PMQR) genes in fluoroquinolone-resistant Escherichia coli recovered from wastewater generated by healthcare institutions. MATERIALS AND METHODS: Isolation of fluoroquinolone-resistant Escherichia coli was done on medium supplemented with 1 µg/mL of ciprofloxacin (a fluoroquinolone). Presumptive isolates were identified via the detection of uidA gene. Susceptibility of the isolates to a panel of antibiotics was done using disc diffusion method. Detection of PMQR genes in the isolates was done using primer-specific PCR. RESULTS: Thirty fluoroquinolone-resistant Escherichia coli were obtained from the wastewater over a period of 6 months. The resistance to each of the antibiotic tested was: ampicillin (100%), ceftriaxone (100%), nalidixic acid (100%), tetracycline (96.7%), cefotaxime (96.7%), amoxicillin-clavulanate (80%), gentamicin (60%), cefoxitin (30%), and imipenem (3.3%). The Multiple Antibiotic Resistance Index (MARI) ranged from 0.6 to 0.9. The detection of PMQR genes in the 30 isolates was: qnrA (76.7%), qnrB (53.3%), qnrS (63.3%), aac(6')-lb-cr (43.3%), and qepA (43.3%). All the fluoroquinolone-resistant Escherichia coli carried at least one PMQR determinant. CONCLUSION: This study revealed that untreated hospital wastewaters are significant hub of multidrug-resistant and fluoroquinolone-resistant Escherichia coli, showing high carriage of PMQR genes, and may be a major contributor to the resistome of fluoroquinolone-resistant bacteria in the Nigerian environment.202540552214
117740.9999High carriage of plasmid-mediated quinolone resistance (PMQR) genes by cefotaxime-resistant Escherichia coli recovered from surface-leaking sanitary sewers. There is a rapid rise in the incidence of quinolone resistant bacteria in Nigeria. Most studies in Nigeria have focused on isolates from the clinical settings, with few focusing on isolates of environmental origin. This study aimed to investigate the antibiogram and carriage of plasmid-mediated quinolone resistance (PMQR) genes by quinolone-resistant isolates obtained from a pool of cefotaxime-resistant Escherichia coli (E. coli) recovered from sewage leaking out of some surface-leaking sanitary sewers in a University community in Nigeria. Isolation of E. coli from the sewage samples was done on CHROMagar E. coli, after enrichment of the samples was done in Brain Heart Infusion broth amended with 6 µg/mL of cefotaxime. Identification of presumptive E. coli was done using molecular methods (detection of uidA gene), while susceptibility to antibiotics was carried out using the disc diffusion method. Detection of PMQR genes (qnrA, qnrB, qnrS, aac(6')-lb-cr, qepA and oqxAB) was carried out using primer-specific PCR. A total of 32 non-repetitive cefotaxime-resistant E. coli were obtained from the sewage, with 21 being quinolone-resistant. The quinolone-resistant isolates showed varying level of resistance to the tested antibiotics, with imipenem being the only exception with 0% resistance. The PMQR genes: aac(6')-lb-cr, qnrA, qnrB, qnrS and qepA and oqxAB were detected in 90.5%, 61.9%, 47.6%, 38.1%, 4.8% and 0% respectively of the isolates. The findings of this study showed a high level of resistance to antibiotics and carriage of PMQR genes by quinolone-resistant E. coli obtained from the leaking sanitary sewers, suggesting a potential environmental and public health concern.202235000007
103650.9999Detection of carbapenem resistance genes and cephalosporin, and quinolone resistance genes along with oqxAB gene in Escherichia coli in hospital wastewater: a matter of concern. AIMS: This study was performed to detect the presence of Escherichia coli resistant to cephalosporins, carbapenems and quinolones in hospital wastewater. METHODS AND RESULTS: Wastewaters from a rural (H1) and an urban (H2) hospital were tested for E. coli resistant to cephalosporins, carbapenem and quinolones. Genes coding for chromosomal and plasmid-mediated resistance and phylogenetic grouping was detected by multiplex polymerase chain reaction (PCR) and for genetic relatedness by rep-PCR. Of 190 (H1 = 94; H2 = 96) E. coli examined, 44% were resistant to both cephalosporins and quinolones and 3% to imipenem. ESBLs were detected phenotypically in 96% of the isolates, the gene blaCTX-M coding for 87% and blaTEM for 63%. Quinolone resistance was due to mutations in gyrA and parC genes in 97% and plasmid-coded aac-(6')-Ib-cr in 89% of isolates. Only in one carbapenem-resistant E. coli, NDM-1 was detected. Nearly 67% of the isolates belonged to phylogenetic group B2. There was no genetic relatedness among the isolates. CONCLUSIONS: Hospital wastewater contains genetically diverse multidrug-resistant E. coli. SIGNIFICANCE AND IMPACT OF THE STUDY: This study stresses the need for efficient water treatment plants in healthcare settings as a public health measure to minimize spread of multidrug-resistant bacteria into the environment.201424975198
117360.9999Investigation of plasmid-mediated quinolone resistance in Pseudomonas aeruginosa clinical isolates. AIMS: To investigate plasmid-mediated quinolone resistance in clinical isolates of Pseudomonas aeruginosa with the polymerase chain reaction (PCR). The plasmid-mediated quinolone resistance genes have been identified in many bacteria within the Enterobactericeae family, they have not been detected in P. aeruginosa isolates. Subjects and Methods : Identification of the isolates and testing of antibiotic susceptibility was performed in Vitek2 Compact (Biomeriux, France) and Phoinex (BD, USA) automated systems. Screening for the qnrA, qnrB, qnrS, qnrC, aac (6')-Ib-cr and qepA genes was carried out by PCR amplification and aac (6')-Ib-cr DNA sequencing. RESULTS: The qnr and the qepA genes were not detected in any of P. aeruginosa isolates. The aac (6')-Ib gene was detected in six of the isolates and positive isolates for aac (6')-Ib were sequenced for detection of the aac (6')-Ib-cr variant but aac (6')-Ib-cr was not detected in any isolates. CONCLUSIONS: Plasmid-mediated quinolone resistance genes have so far not been identified in P. aeruginosa isolates. However, qnrB have detected in P. florescens and P. putida isolates. This is the first study conducted on the qnrA, qnrB, qnrS and qnrC genes as well as the qepA and aac (6')-Ib-cr genes in P. aeruginosa clinical isolates.201425008822
96770.9998Characterization of Integrons and Quinolone Resistance in Clinical Escherichia coli Isolates in Mansoura City, Egypt. Escherichia coli is a common pathogen in both humans and animals. Quinolones are used to treat infections caused by Gram-negative bacteria, but resistance genes emerged. Only scarce studies investigated the association between plasmid-mediated quinolone resistance (PMQR) genes and integrons in clinical isolates of E. coli. The current study investigated the prevalence of quinolone resistance and integrons among 134 clinical E. coli isolates. Eighty (59.70%) isolates were quinolone-resistant, and 60/134 (44.77%) isolates were integron positive with the predominance of class I integrons (98.33%). There was a significant association between quinolone resistance and the presence of integrons (P < 0.0001). Isolates from Urology and Nephrology Center and Gastroenterology Hospital were significantly quinolone-resistant and integron positive (P ≤ 0.0005). Detection of PMQR genes on plasmids of integron-positive isolates showed that the active efflux pump genes oqxAB and qepA had the highest prevalence (72.22%), followed by the aminoglycoside acetyltransferase gene (aac(6')-Ib-cr, 66.67%) and the quinolone resistance genes (qnr, 61.11%). Amplification and sequencing of integrons' variable regions illustrated that no quinolone resistance genes were detected, and the most predominant gene cassettes were for trimethoprim and aminoglycoside resistance including dfrA17, dfrB4, and dfrA17-aadA5. In conclusion, this study reported the high prevalence of PMQR genes and integrons among clinical E. coli isolates. Although PMQR genes are not cassette-born, they were associated with integrons' presence, which contributes to the widespread of quinolone resistance in Egypt.202134527054
89580.9998The determination of gyrA and parC mutations and the prevalence of plasmid-mediated quinolone resistance genes in carbapenem resistant Klebsiella pneumonia ST11 and ST76 strains isolated from patients in Heilongjiang Province, China. BACKGROUND: There is increasing resistance to carbapenems among Klebsiella pneumoniae,and fluoroquinolones (FQ) are increasingly used to treat infections from extended-spectrum β- lactamase(ESBLs) and carbapenemase-producing Klebsiella pneumoniae. However, the acquisition of plasmid-mediated quinolone resistance (PMQR) or the spontaneous mutation of the quinolone resistance-determining regions (QRDR) of the gyrA and parC genes can severely affect the therapeutic effect of quinolones. The goal of this study was to investigate the molecular determinants of FQ resistance(FQ-R) in carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates from Heilongjiang Province,China. MATERIALS AND METHODS: We isolated 40 strains of CRKP from a treatment center in the eastern part of Heilongjiang Province from January 2016 to December 2018. The VITEK2 Compact analyzer was used to identify and detect drug sensitivity. Different types of drug resistance genes were detected by polymerase chain reaction (PCR). PCR and DNA sequencing were used to assess the presence of qnrA, qnrB, qnrS,qepA and acc(6') Ib-cr genes,which are plasmid-encode genes that can contribute to resistance. The sequences of gyrA and parC genes were sequenced and compared with the sequences of standard strains to determine if mutations were present.Multi-site sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were performed on the strains to assess homology. RESULTS: The isolated CRKP strains showed rates of resistance to fluoroquinolones of 22.5% to 42.5%. The resistance rate of ciprofloxacin was significantly higher than that of levofloxacin.Nine CRKP strains (22.5%) showed co-resistance to ciprofloxacin and levofloxacin.The quinolone resistant strains were screened for plasmid-encoded genes that can contribute to resistance (PMQR genes).Among the 17 quinolone resistant strains,one strain contained no PMQR genes,twelve strains contained two PMQR genes,and four strains contained four PMQR genes.Acc (6') Ib-cr was the most frequently detected PMQR gene, detected in 95% of strains tested (38 of 40) and in 94.1% of the quinolone-resistant strains (16 of 17). The qepA gene encoding an efflux pump was not detected in any strains.No isolate carried five different PMQRs simultaneously.Changes of S83I and D87G changes in gyrA, and the S80I change in parC,which were mediated by QRDR,were identified in two isolates,which showed resistance to both ciprofloxacin and levofloxacin.Most of the FQ-R strains(58.8%,10/17) belong to ST(sequence type) 76, which is dominant in the local area, while all the mutant strains (100%,2/2),that differ in at least one site from standard bacteria, belong to the ST11 group. The strains were isolated from a hospital where there had been a recent outbreak of ST76 type CRKP in the neurosurgery ward and intensive care unit. CONCLUSION: CRKP strains were identified that were insensitive or even resistant to quinolones,and this resistance is common in Heilongjiang Province of eastern China;fluoroquinolone-resistance in these clinical CRKP strains is a complex interplay between PMQR determinants and mutations in gyrA and parC.The resistance level caused by QRDR mutation is higher than that caused by PMQR, however, the high frequency of PMQR genes in the isolated CRKP strains suggests the potential for impact of these genes.PMQR determinants are often found in carbapenemase-producing or ESBLs-producing Klebsiella pneumoniae,and some resistance genes,such as:SHV,TEM, CTX-M-15,and OXA-1 are closely associated with FQ-R. Finally, geographical factors can affect the emergence and spread of PMQR and QRDR.Some genetic lineages have higher potential risks, and continuous close monitoring is required.202032278145
110790.9998Prevalence of plasmid-mediated quinolone resistance genes among ciprofloxacin-nonsusceptible Escherichia coli and Klebsiella pneumoniae isolated from blood cultures in Korea. OBJECTIVES: To analyze the prevalence of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-nonsusceptible Escherichia coli and Klebsiella pneumoniae isolated from patients at a tertiary care hospital in Korea. METHODS: A total of 102 nonduplicate isolates of ciprofloxacin-intermediate or ciprofloxacin-resistant E coli (n=80) and K pneumoniae (n=22) from blood cultures were obtained. The qnr (qnrA, qnrB, qnrS), aac(6')-Ib-cr, qepA and oqxAB genes were detected using polymerase chain reaction (PCR) and confirmed using direct sequencing. To determine whether the PMQR-positive plasmid was horizontally transferable, conjugation experiments were performed. RESULTS: Of the 102 isolates, 81 (79.4%) had one or more PMQR genes; these consisted of 59 (73.8%) E coli and 22 (100%) K pneumoniae isolates. The qnr genes were present in 15 isolates (14.7%): qnrB4 was detected in 10.8% and qnrS1 was detected in 3.9%. The aac(6')-Ib-cr, qepA and oqxAB genes were detected in 77.5%, 3.9% and 10.8%, respectively. In conjugation experiments, PMQR genes were successfully transferred from seven (8.6%) isolates. The range of minimum inhibitory concentrations of ciprofloxacin for these seven transconjugants increased to 0.5 mg/L to 1 mg/L, which was 16- to 33-fold that of the recipient E coli J53 bacteria. CONCLUSIONS: PMQR genes were highly prevalent among ciprofloxacin-nonsusceptible E coli and K pneumoniae from blood cultures in the authors' hospital. Therefore, it is necessary to monitor for the spread of PMQR genes of clinical isolates and to ensure careful antibiotic use in a hospital setting.201425285114
964100.9998Distribution of plasmid-mediated quinolone resistance in Gram-negative bacteria from a tertiary hospital in Nigeria. BACKGROUND: Until recently, mechanisms of resistance to quinolones in Gram-negative bacteria were believed to be only chromosome encoded. However, emergence of plasmid-mediated quinolone resistance (PMQR) has been reported worldwide. AIM: This study investigated distribution of PMQR in Gram-negative bacteria from a tertiary hospital in eastern part of Nigeria. MATERIALS AND METHODS: Seventy-one nonduplicate Gram-negative bacterial isolates of eight species were analyzed for antimicrobial susceptibility, genotypic detection of various PMQRs, typed by random amplified polymorphic DNA (RAPD) and analysis of plasmids present, including replicon typing. RESULTS: The minimum inhibitory concentrations showed MIC90values as high as 256 μg/ml for fluoroquinolones. Carriage of PMQR was found to be 35.2%. Twenty (28.2%) isolates carried various qnr genes, of which seven (9.9%) qnrA1; four (5.6%) qnrB1; eight (11.3%) qnrS1 while one (1.4%) encoded qnrD1. Eighteen (25.4%) isolates were positive for aac(6')-Ib-cr while carriage of multiple genes exists in some strains. Similarly, 13 isolates (18.7%) were found to carry PMQR efflux pump gene, qepA. Conjugation experiments revealed that the plasmids once transferred coded for fluoroquinolone resistance. The transconjugant strains carried a common plasmid estimated to be 65 kb. These plasmids were untypable for replicon/incompatibility. Typing revealed high diversity among all species tested with no identical RAPD pattern seen. CONCLUSION: This study further confirms high level resistance to many antimicrobials in different species of Gram-negative bacteria including fluoroquinolones and spread of PMQR genes in Southern Nigeria.201627510669
897110.9998Prevalence of class 1 integrons and plasmid-mediated qnr-genes among Enterobacter isolates obtained from hospitalized patients in Ahvaz, Iran. Quinolones are frequently used classes of antimicrobials in hospitals, crucial for the treatment of infections caused by Gram-negative bacteria. The inappropriate use of quinolones and other antimicrobial agents for the treatment of bacterial infections leads to a significant increase of resistant isolates. The acquisition of antimicrobial resistance may be related to achievement of resistance determinant genes mediated by plasmids, transposons and gene cassettes in integrons. The objective of this cross-sectional study, conducted from December 2015 to July 2016 at two teaching hospitals in Ahvaz, southern Iran, was to screen for the presence of class 1 integrons and quinolone resistance genes in clinical isolates of Enterobacter spp. In all, 152 non-duplicated Enterobacter isolates were collected from clinical specimens and identified as Enterobacter spp. using standard microbiological methods. Antimicrobial susceptibility test was determined using the disc diffusion method according to the CLSI recommendation. Determination of class 1 integrons and PMQR genes was assessed by PCR. Analysis of antibiotic susceptibility tests showed that the highest antibiotic resistance was toward ciprofloxacin (55.3%), while the lowest level was observed against meropenem (34.9%). Moreover, 47.4% (72/152) and 29% (44/152) of isolates were positive for class 1 integron and quinolone resistance genes, respectively. The relative frequencies of antibiotic resistance were significantly higher among class 1 integron-positive isolates. In summary, our results highlight the importance of PMQR genes in the emergence of quinolone-resistant Enterobacter isolates. Moreover, it seems that class 1 integrons have a widespread distribution among Enterobacter isolates and have clinical relevance to multiple-drug-resistant isolates.201729286015
2054120.9998A survey of plasmid-mediated fluoroquinolone resistance genes from Escherichia coli isolates and their dissemination in Shandong, China. Bacterial resistance to fluoroquinolones result from mutations in the quinolone resistance-determining regions of the drug targets, overexpression of efflux pumps, and/or the more recently identified plasmid-mediated low-level resistance mechanisms. We investigated the prevalence of and characterized plasmid-mediated fluoroquinolone resistance genes (qnrA, qnrB, qnrS, aac(6')-Ib-cr, and qepA) by polymerase chain reaction in fluoroquinolone-resistant Escherichia coli (n = 530) isolated from a chicken farm, a pig farm, and hospitalized patients in Shandong, China, in 2007. The aac(6')-Ib-cr gene was the most prevalent resistance gene that was detected in bacteria isolated from all sources. Next was the qnrS gene, which was predominantly present in isolates from the pig farm. Only eight (5.8%) isolates from hospital patients were found to possess the qepA gene, and these isolates were first reported in qepA-carrying E. coli from humans in China. The qnrA and qnrB genes were not detected in any of the isolates. Further, most of the isolates were also resistant to beta-lactams and aminoglycosides as determined by the broth microdilution method. Pulsed-field gel electrophoresis analysis of the E. coli isolates with similar resistance patterns that also carried resistance genes showed great genomic diversity among these bacteria, suggesting that the multiresistant E. coli isolates carrying the qnr, aac(6')-Ib-cr, or qepA genes were not derived from a specific clone, but represented a wide variety of different genotypes. The results of Southern hybridization revealed that qepA, qnrS, and parts of aac(6')-Ib-cr genes were localized on plasmids and/or chromosome. qepA and aac(6')-Ib-cr genes were colocalized with aac(6')-Ib-cr and qnrS genes, respectively, on the same plasmids. Our study demonstrated that two different genes (qepA and aac(6')-Ib-cr) were identified on the same plasmid in E. coli strains derived from patients and qnrS and aac(6')-lb-cr genes on the same plasmid in an E. coli strain of animal origin.201019911944
1127130.9998Extended spectrum beta-lactamase and aminoglycoside modifying enzyme genes in multi drug resistant Gram-negative bacteria: A snapshot from a tertiary care centre. BACKGROUND: This study aims to enhance the existing knowledge of the prevalence of genes responsible for beta-lactam resistance and aminoglycoside resistance in gram negative organisms by molecular detection of extended spectrum beta-lactamase and aminoglycoside modifying enzymes in multidrug-resistant gram-negative bacteria. METHODS: Out of 864 gram-negative isolates, 710 were phenotypically identified as multidrug-resistant by antibiotic susceptibility testing. From the above isolates, 102 representative isolates as per sample size calculated were selected for further molecular studies. The presence of blaTEM, blaCTX-M blaSHV, and five AmpC genes was detected by real-time polymerase chain reaction (PCR). Conventional PCR was performed to detect seven aminoglycoside modifying enzyme genes namely aac(6')-Ib, aac(6')-Ic, aac(3)-Ia, aac(3)-Ib, aac(3)-IIa, ant(2'')-Ia, and ant(4'')-IIa. RESULTS: Most common multidrug-resistant isolate was Klebsiella pneumoniae (35%) followed by Escherichia coli (30%). Among the 102 selected isolates all harboured blaTEM gene, 71 (69.6%) harboured blaCTX-M gene and 48 (47%) blaSHV gene. Among the selected isolates 60% showed the presence of AmpC genes. Most common aminoglycosie modifying enzyme gene was AAC 6' Ib (51%) followed by ANT 2" Ia (36%). CONCLUSION: This study suggests a wider use of molecular methods using specific PCR amplification of resistance genes. It would be beneficial to perform the molecular identification of antimicrobial resistance genes to effectively monitor and manage antibiotic resistance, administer appropriate antimicrobial medication, practice antimicrobial stewardship and improve hospital infection control procedures.202439734850
1031140.9998Beta-lactams resistance and presence of class 1 integron in Pseudomonas spp. isolated from untreated hospital effluents in Brazil. The aim of the present study was to investigate the resistance profile, to detect the presence of beta-lactam resistance genes, phenotypic expression of efflux pump systems and class 1 integrons in Pseudomonas spp. strains obtained from untreated hospital effluents. Effluent samples were collected from four hospitals in Porto Alegre, RS, Brazil. Pseudomonas were isolated on MacConkey agar plates and the identification was confirmed by 16S rRNA PCR and biochemical tests. Susceptibility testing was determined by disk-diffusion method using 11 different beta-lactams and MIC assays were performed on isolates resistant to imipenem and ceftazidime. The beta-lactamase genes bla (IMP), bla (VIM), bla (SPM-1), bla (OXA-23-like), bla (OXA-24-like), bla (OXA-51-like) and the intl1 gene from class 1 integron were analysed by PCR. One hundred and twenty-four isolates were recovered and the most common species was Pseudomonas pseudoalcaligenes. The resistance found among the isolates was considered high, 62 (50%) isolates were multiresistant. No isolate carrying the beta-lactamase genes tested was found among the strains. Seven isolates showed reduction of MIC for imipenem and ceftazidime in the presence of cyanide m-chlorophenylhydrazone, indicating the hyper expression of efflux pumps. From the 124 isolates, 52 (41.9%) were identified as carrying the class 1 integron gene, intI1. Untreated hospital effluents could be a source of environmental contamination due to discharge of antimicrobial resistant bacteria which can carry integron class 1 and act as a reservoir of resistance genes and have efflux pump systems.201222382676
1086150.9998Antimicrobial Resistance Profiles and Co-Existence of Multiple Antimicrobial Resistance Genes in mcr-Harbouring Colistin-Resistant Enterobacteriaceae Isolates Recovered from Poultry and Poultry Meats in Malaysia. The co-existence of the colistin resistance (mcr) gene with multiple drug-resistance genes has raised concerns about the possibility of the development of pan-drug-resistant bacteria that will complicate treatment. This study aimed to investigate the antibiotic resistance profiles and co-existence of antibiotic resistance genes among the colistin-resistant Enterobacteriaceae isolates recovered from poultry and poultry meats. The antibiotic susceptibility to various classes of antibiotics was performed using the Kirby-Bauer disk diffusion method and selected antimicrobial resistance genes were detected using PCR in a total of 54 colistin-resistant Enterobacteriaceae isolates including Escherichia coli (E. coli) (n = 32), Salmonella spp. (n = 16) and Klebsiella pneumoniae (K. pneumoniae) (n = 6) isolates. Most of the isolates had multi-drug resistance (MDR), with antibiotic resistance against up to seven classes of antibiotics. All mcr-harbouring, colistin-resistant Enterobacteriaceae isolates showed this MDR (100%) phenotype. The mcr-1 harbouring E. coli isolates were co-harbouring multiple antibiotic resistance genes. The seven most commonly identified resistance genes ((bla)TEM, tetA, floR, aac-3-IV, aadA1, fosA, aac(6_)-lb) were detected in an mcr-1-harbouring E. coli isolate recovered from a cloacal swab. The mcr-5 harbouring Salmonella spp. isolate recovered from poultry meats was positive for (bla)TEM, tetA, floR, aac-3-IV, fosA and aac(6_)-lb genes. In conclusion, the colistin-resistant Enterobacteriaceae with mcr genes co-existing multiple clinically important antimicrobial resistance genes in poultry and poultry meats may cause potential future threats to infection treatment choices in humans and animals.202337370378
1078160.9998Prevalence of integrons, blaCTX-M and blaTEM resistance markers among ESBL-producing uropathogenic Escherichia coli isolates: first report of genomic blaCTX-M from India. Integrons have been observed to be frequently associated with uropathogenic bacteria. This study aimed at 1) determining the prevalence of class 1 integrons among ESBLl-producing uropathogenic Escherichia coli, and 2) analyzing resistance genes associated with different phylogenetic groups of the integron-positive isolates with special reference to bla(CTX-M) and bla(TEM). Twenty-three ESBL-producing E. coli were studied. Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) displayed 14 major patterns. Pulse field Gel electrophoresis-typing of 8 randomly selected integron-positive strains ruled out any correlation between genotype and antibiotype. Genomic DNA from 14 strains was PCR-positive for class 1 integrons, bla(CTX-M-15) and bla(TEM-1)-like genes. Integron-sequencing revealed "aadA5-dfrA17-dfrA7" as the most prevalent gene cassette. Our findings unveil the increasing role of the bla(CTX-M) genes in antibiotic resistance and emphasize on the significance of appropriate empirical treatment for Urinary tract infections. Moreover, this is the first study which reports bla(CTX-M) located on genomic DNA of bacteria from India.201121742580
1069170.9998High Prevalence of Antimicrobial Resistance in Gram-Negative Bacteria Isolated from Clinical Settings in Egypt: Recalling for Judicious Use of Conventional Antimicrobials in Developing Nations. This study was designed to investigate, at the molecular level, the antimicrobial resistance mechanisms of different antimicrobial resistance genes, including, extended-spectrum β-lactamases, AmpC β-lactamases, class 1 and 2 integrons, and plasmid-mediated quinolone resistance genes of Gram-negative bacteria isolated from clinical settings in Egypt. A total of 126 nonduplicate Gram-negative isolates were recovered from different clinical samples taken from hospitalized patients in Egypt in 2014. Antimicrobial susceptibility testing showed that, 93.6% (118/126) of the isolates had a multidrug-resistant phenotype. Interestingly, we reported a high level of antimicrobial resistance nearly for all tested antibiotics; to our knowledge, this is the first report from Egypt indicating very high level of antibiotic resistance in Egypt. Polymerase chain reaction screening and DNA sequencing revealed that, 75.4% (95/126) of the isolates harbored at least one extended-spectrum β-lactamase-encoding gene, with bla(CTX-M) being the most prevalent (65.9%), followed by bla(SHV) (46.8%). The AmpC β-lactamase, bla(CMY), was detected in 7.1% (9/126) of bacterial isolates, with bla(CMY-42) being the most prevalent. Class 1 integrons were detected in 50.8% (64/126) of the isolates, and class 2 integrons were detected in 2.4% (3/126) of the isolates. The plasmid-mediated quinolone resistance gene, qnr, was detected in 58.7% (74/126) of the tested isolates, with qnrS being the most prevalent. Several antimicrobial resistance determinants were identified in Egypt for the first time, such as SHV-27, SHV-28, SHV-33, SHV-63, SHV-71, SHV-82, SHV-142, CMY-42, CMY-6, and the new CMY-72 like. This study highlights the importance of the conscious use of conventional antimicrobials to overcome the multidrug resistance problem.201930681401
1156180.9998Detection of qnr, aac(6')-Ib-cr and qepA genes in Escherichia coli isolated from cooked meat products in Henan, China. Antimicrobial resistance in Escherichia coli has increased in recent years in China. Antimicrobial resistant isolates and resistance genes of E. coli can be transferred to humans through the food chain and this presents a public health risk. However, few studies have investigated the prevalence of antimicrobial resistance-encoding genes in E. coli isolated from food samples in China. The aim of this study was to investigate the presence of quinolone resistance genes (QRGs) and extended-spectrum β-lactamases (ESBLs) in E. coli isolated from cooked meat products in Henan, China. A total of 75 E. coli isolates (12.1%) were detected from 620 samples. High rates of resistance to the following drugs were observed: tetracycline (56.0%), trimethoprim/sulfamethoxazole (41.3%), streptomycin (29.3%), ampicillin (26.7%) and nalidixic acid (14.7%). Of the 75 isolates, QRGs were present in 10 isolates (13.3%), with qnr and aac(6')-Ib-cr detected alone or in combination in five (6.7%) and eight isolates (10.7%). The qnr genes detected in this study included qnrS (n=3) and qnrA (n=2). The qepA gene was absent among these isolates. Three types of β-lactamase genes were identified in the five ESBL-producing E. coli isolates: blaCTX-M-1, blaCTX-M-9, and blaTEM-1. The qnrS gene was found to be co-transferred with blaCTX-M-1 and blaTEM-1 in one isolate. Our data suggest that cooked meat products may act as reservoirs for multi-resistant bacteria and facilitate the dissemination of antimicrobial resistance genes.201425036771
968190.9998Molecular analysis of antimicrobial resistance in gram-negative bacteria isolated from fish farms in Egypt. As little is known about antimicrobial resistance genes in fish farms, this study was conducted to monitor the incidence and prevalence of a wide range of antimicrobial resistance genes in Gram-negative bacteria isolated from water samples taken from fish farms in the northern part of Egypt. Ninety-one out of two hundred seventy-four (33.2%) non-repetitive isolates of Gram-negative bacteria showed multidrug resistance phenotypes and harbored at least one antimicrobial resistance gene. PCR and DNA sequencing results showed that 72 (26.3%) isolates contain tetracycline resistance genes and 19 (6.9%) isolates were positive for class 1 integrons with 12 different gene cassettes. The beta-lactamase-encoding genes were identified in 14 (5.1%) isolates. The plasmid-mediated quinolone resistance genes, qnr and aac(6')-Ib-cr, were identified in 16 (5.8%) and 3 (1.1%) isolates, respectively. Finally, the florphenicol resistance gene, floR, was identified in four (1.5%) isolates. To the best of our knowledge, this is the first report for molecular characterization of antimicrobial resistance in Gram-negative bacteria isolated from fish farms in Africa.201020145377