Tunisian Multicenter Study on the Prevalence of Colistin Resistance in Clinical Isolates of Gram Negative Bacilli: Emergence of Escherichia coli Harbouring the mcr-1 Gene. - Related Documents




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150201.0000Tunisian Multicenter Study on the Prevalence of Colistin Resistance in Clinical Isolates of Gram Negative Bacilli: Emergence of Escherichia coli Harbouring the mcr-1 Gene. BACKGROUND: Actually, no data on the prevalence of plasmid colistin resistance in Tunisia are available among clinical bacteria. OBJECTIVES: This study aimed to investigate the current epidemiology of colistin resistance and the spread of the mcr gene in clinical Gram-negative bacteria (GNB) isolated from six Tunisian university hospitals. METHODS: A total of 836 GNB strains were inoculated on COL-R agar plates with selective screening agar for the isolation of GNB resistant to colistin. For the selected isolates, mcr genes, beta-lactamases associated-resistance genes and molecular characterisation were screened by PCRs and sequencing. RESULTS: Colistin-resistance was detected in 5.02% (42/836) of the isolates and colistin-resistant isolates harboured an ESBL (bla(CTX-M-15)) and/or a carbapenemase (bla(OXA-48), bla(VIM)) encoding gene in 45.2% of the cases. The mcr-1 gene was detected in four E. coli isolates (0.59%) causing urinary tract infections and all these isolates also contained the bla(TEM-1) gene. The bla(CTX-M-15) gene was detected in three isolates that also carried the IncY and IncFIB replicons. The genetic environment surrounding the mcr-carrying plasmid indicated the presence of pap-2 gene upstream mcr-1 resistance marker with unusual missing of ISApl1 insertion sequence. THE CONCLUSIONS: This study reports the first description of the mcr-1 gene among clinical E. coli isolates in Tunisia and provides an incentive to conduct routine colistin susceptibility testing in GNB clinical isolates.202236290048
150310.9999OXA-48 Carbapenemase-Encoding Transferable Plasmids of Klebsiella pneumoniae Recovered from Egyptian Patients Suffering from Complicated Urinary Tract Infections. Gram-negative bacteria are common causes of urinary tract infections (UTIs). Such pathogens can acquire genes encoding multiple mechanisms of antimicrobial resistance, including carbapenem resistance. The aim of this study was to detect the carbapenemase-producing ability of some Gram-negative bacterial isolates from urine specimens of patients suffering from complicated UTIs at two vital tertiary care hospitals in Cairo, Egypt; to determine the prevalence of carbapenemase genes among plasmid-bearing isolates; and explore the possibility of horizontal gene transfer to other bacterial species. The collected isolates were subjected to antimicrobial susceptibility testing, phenotypic analysis of carbapenemase production, and molecular detection of plasmid-borne carbapenemase genes, then the extracted plasmids were transformed into competent E. coli DH5α. A total of 256 Gram-negative bacterial clinical isolates were collected, 65 (25.4%) isolates showed carbapenem resistance of which 36 (55.4%) were carbapenemase-producers, and of these 31 (47.7%) harbored plasmids. The extracted plasmids were used as templates for PCR amplification of bla(KPC), bla(NDM), bla(VIM), bla(OXA-48,) and bla(IMP) carbapenemase genes. The bla(OXA-48) gene was detected in 24 (77.4%) of the tested isolates while bla(VIM) gene was detected in 8 (25.8%), both bla(KPC) and bla(NDM) genes were co-present in 1 (3.2%) isolate. Plasmids carrying the bla(OXA-48) gene from 4 K. pneumoniae clinical isolates were successfully transformed into competent E. coli DH5α. The transformants were carbapenemase-producers and acquired resistance to some of the tested antimicrobial agents as compared to untransformed E. coli DH5α. The study concluded that the rate of carbapenem resistance among Gram-negative bacterial uropathogens in Cairo, Egypt is relatively high and can be transferred horizontally to other bacterial host(s).202134571766
150020.9999Microbiological surveillance of plasmid mediated colistin resistance in human Enterobacteriaceae isolates in Romagna (Northern Italy): August 2016-July 2017. OBJECTIVES: To start a surveillance program to investigate the possible diffusion of mobilized colistin resistance genes in Enterobacteriaceae strains isolated in the Unit of Microbiology of the Great Romagna Hub Laboratory. METHODS: All the colistin resistant Enterobacteriaceae, isolated from August 1st 2016 to July 31st 2017, were prospectively evaluated for mcr-1 and mcr-2. Backdated survey of mcr-3, mcr-4 and mcr-5 was performed on the same group of isolates. Species identification was achieved by Vitek MS and the antibiotic susceptibility testing was performed both with Vitek-2 and Sensititre systems. Colistin resistant isolates were screened by PCR for the presence of the plasmid-mediated colistin resistance genes and amplicons were verified by sequencing. All mcr-1 positive isolates were subjected to MLST analysis. RESULTS: Over the total of 19053 isolates belonging to Enterobacteriaceae, 90 were colistin resistant. The presence of mcr-1 was detected in 26 Escherichia coli. The overall prevalence of mcr-1 was 0.14%. The mcr-1 positive E. coli strains were assigned to 13 distinct sequence types (STs) according to MLST. CONCLUSIONS: The prospective epidemiological survey carried out in our study gave a glimpse of the plasmid-mediated colistin resistance dissemination in Romagna. Since the prevalence rate of carbapenem resistant Enterobacteriaceae (CRE) in some hospital wards in our area is alarming, we underline the importance of a Surveillance Program to monitor the spread of the plasmid-mediated colistin resistance genes into MDR Gram-negative bacteria.201829447913
150130.9999High-level and novel mechanisms of carbapenem resistance in Gram-negative bacteria from tertiary hospitals in Nigeria. To determine the occurrence and molecular basis of carbapenem resistance in Gram-negative bacteria from tertiary hospitals in Nigeria, 182 non-duplicate Gram-negative bacterial isolates were investigated for antimicrobial susceptibility, presence of carbapenemases (tested phenotypically and genotypically), random amplified polymorphic DNA (RAPD) typing, plasmid sizing and replicon typing. Minimum inhibitory concentrations of carbapenems showed a high degree of resistance, with 67 isolates (36.8%) being resistant to all carbapenems, of which 40 (59.7%) produced enzymes able to hydrolyse imipenem. PCR and sequencing identified only 10 isolates (5.5%) carrying known carbapenemase genes, including bla(NDM), bla(VIM) and bla(GES). The majority of phenotypically carbapenem-resistant and carbapenemase-producing isolates did not carry a known carbapenemase gene. Transconjugant or transformant plasmid sizes were estimated to be 115 kb for bla(NDM)- and 93 kb for bla(VIM)-carrying plasmids. These plasmids were untypeable for replicon/incompatibility and transferred various other genes including plasmid-mediated quinolone resistance (PMQR) genes and bla(CTX-M-15). Typing showed that the isolates in this study were not clonally related. There is a high level of carbapenem resistance in Nigeria. As well as the globally relevant carbapenemases (bla(NDM), bla(VIM) and bla(GES)), there are other unknown gene(s) or variant(s) in circulation able to hydrolyse carbapenems and confer high-level resistance.201424613608
91240.9999Carbapenem and colistin-resistant bacteria in North Lebanon: Coexistence of mcr-1 and NDM-4 genes in Escherichia coli. INTRODUCTION: The increasing incidence of infections caused by multidrug-resistant bacteria is considered a global health problem. This study aimed to investigate this resistance in Gram-negative bacteria isolated from patients hospitalized in North-Lebanon. METHODOLOGY: All isolates were identified using the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic susceptibility testing was achieved using disk diffusion, E-test and Broth microdilution methods. Phenotypic detection of carbapenemase was carried out using the CarbaNP test. RT-PCR, standard-PCR and sequencing were performed to detect resistance genes and oprD gene. Conjugal transfer was carried out between our isolates and Escherichia coli J53 to detect the genetic localization of resistance genes. MLST was conducted to determine the genotype of each isolate. RESULTS: Twenty-three carbapenem-resistant Enterobacterales of which eight colistin-resistant Escherichia coli, and Twenty carbapenem-resistant Pseudomonas aeruginosa were isolated. All isolates showed an imipenem MIC greater than 32 mg/mL with MICs for colistin greater than 2 mg/L for E. coli isolates. All the Enterobacterales isolates had at least one carbapenemase-encoding gene, with E. coli isolates coharboring blaNDM-4 and mcr-1 genes. Moreover, 16/20 Pseudomonas aeruginosa harbored the blaVIM-2 gene and 18/20 had mutations in the oprD gene. MLST revealed that the isolates belonged to several clones. CONCLUSIONS: We report here the first description in the world of clinical E. coli isolates coharboring blaNDM-4 and mcr-1 genes, and K. pneumoniae isolates producing NDM-6 and OXA-48 carbapenemases. Also, we describe the emergence of NDM-1-producing E. cloacae in Lebanon. Screening for these isolates is necessary to limit the spread of resistant microorganisms in hospitals.202134343118
91550.9999Detection of Plasmid-Mediated Mobile Colistin Resistance Gene (mcr-1) in Enterobacterales Isolates from a University Hospital. PURPOSE: Colistin represents one of the last treatment options for infections caused by multi-drug resistant (MDR) Enterobacterales. The emergence of a plasmid-mediated mobile colistin resistance-1 (mcr-1) gene has raised serious concerns about its potential dissemination among bacteria. METHODS: In this study, we evaluated the chromogenic medium, CHROMID(®) Colistin Resistance (COLR) agar, for the rapid detection of colistin-resistant Enterobacterales using broth microdilution (BMD) as a reference method. We also attempted to detect mcr-1, -2, -3, -4, and -5 genes, as well as the insertion sequence ISApl1 via polymerase chain reaction (PCR), followed by sequencing of mcr gene(s). RESULTS: Among the 100 studied Enterobacterales isolates, 53% of them were colistin-resistant, with higher rate among Klebsiella pneumoniae (75%) as compared to Escherichia coli (44.4%). The COLR agar showed 83.2% sensitivity and 97.9% specificity for the detection of colistin resistance. Among colistin-resistant isolates, mcr-1 gene was only detected in four (7.5%) E. coli isolates. The ISApl1 was not found among mcr-1 positive isolates. Sequencing of mcr-1 gene revealed nucleotide sequence homogeneity with the wild-type mcr-1 gene in BLAST. CONCLUSION: The COLR agar is a promising phenotypic method for the detection of colistin-resistant Enterobacterales. Multiplex PCR followed by sequencing can be used for mcr genes' detection and characterization.202134408450
91960.9999Molecular Characteristics of Carbapenem-Resistant Enterobacter cloacae in Ningxia Province, China. The emergence of carbapenem-resistant Enterobacteriaceae (CRE) has become a major public health concern worldwide and a new challenge in the treatment of infectious diseases. The molecular characteristics of Enterobacter cloacae in Ningxia China are unknown. In this study, we reported 10 carbapenem-resistant E. cloacae isolates from the General Hospital of Ningxia Medical University, the largest university hospital in Ningxia between January 2012 and December 2013. Bacteria isolates were identified by Vitek2 compact and the identity of non-duplicate E. cloacae isolates was further confirmed by PCR and sequencing. The drug susceptibility and phenotype identification of these isolates were analyzed by agar dilution method, modified Hodge test (MHT), and EDTA synergy test. Beta-lactamase (bla) genes bla(NDM-1) was found in 8 out of 10 isolates. Most isolates harbored multiple resistance genes including bla(ESBL), bla(AmpC), quinolones, aminoglycosides, and disinfectant resistance genes. Pulsed field gel electrophoresis (PFGE) showed that these E. cloacae isolates were grouped into 6 clusters based on a cutoff of 80% genetic similarity. In conjugative assay, 9 out of 10 isolates transferred carbapenem-resistant genes to Escherichia coli. Our study has revealed that NDM-1-producing isolates are the most prevalent carbapenem-resistant E. cloacae in Ningxia. These isolates also carry several other carbapenem-resistant genes and can transfer these genes to other bacteria through conjugation. These findings highlight an urgent need to monitor these isolates to prevent their further spread in this region.201728197140
90970.9999First Description of Colistin and Tigecycline-Resistant Acinetobacter baumannii Producing KPC-3 Carbapenemase in Portugal. Herein, we describe a case report of carbapenem-resistant Acinetobacter baumannii and Klebsiella pneumoniae isolates that were identified from the same patient at a Tertiary University Hospital Centre in Portugal. Antimicrobial susceptibility and the molecular characterization of resistance and virulence determinants were performed. PCR screening identified the presence of the resistance genes bla(KPC-3), bla(TEM-1) and bla(SHV-1) in both isolates. The KPC-3 K. pneumoniae isolate belonged to the ST-14 high risk clone and accumulated an uncommon resistance and virulence profile additional to a horizontal dissemination capacity. In conclusion, the molecular screening led to the first identification of the A. baumannii KPC-3 producer in Portugal with a full antimicrobial resistance profile including tigecycline and colistin.201830404152
107180.9999Characterization of Beta-Lactamase and Fluoroquinolone Resistance Determinants in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa Isolates from a Tertiary Hospital in Yola, Nigeria. Infections due to antimicrobial resistant gram-negative bacteria cause significant morbidity and mortality in sub-Saharan Africa. To elucidate the molecular epidemiology of antimicrobial resistance in gram-negative bacteria, we characterized beta-lactam and fluoroquinolone resistance determinants in Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolates collected from November 2017 to February 2018 (Period 1) and October 2021 to January 2022 (Period 2) in a tertiary medical center in north-eastern Nigeria. Whole genome sequencing (WGS) was used to identify sequence types and resistance determinants in 52 non-duplicate, phenotypically resistant isolates. Antimicrobial susceptibility was determined using broth microdilution and modified Kirby-Bauer disk diffusion methods. Twenty sequence types (STs) were identified among isolates from both periods using WGS, with increased strain diversity observed in Period 2. Common ESBL genes identified included bla(CTX-M), bla(SHV,) and bla(TEM) in both E. coli and K. pneumoniae. Notably, 50% of the E. coli in Period 2 harbored either bla(CTX-M-15) or bla(CTX-M-1 4) and phenotypically produced ESBLs. The bla(NDM-7) and bla(VIM-5) metallo-beta-lactamase genes were dominant in E. coli and P. aeruginosa in Period 1, but in Period 2, only K. pneumoniae contained bla(NDM-7), while bla(NDM-1) was predominant in P. aeruginosa. The overall rate of fluoroquinolone resistance was 77% in Period 1 but decreased to 47.8% in Period 2. Various plasmid-mediated quinolone resistance (PMQR) genes were identified in both periods, including aac(6')-Ib-cr, oqxA/oqxB, qnrA1, qnrB1, qnrB6, qnrB18, qnrVC1, as well as mutations in the chromosomal gyrA, parC and parE genes. One E. coli isolate in Period 2, which was phenotypically multidrug resistant, had ESBL bla(CTX-M-15,) the serine carbapenemase, bla(OXA-181) and mutations in the gyrA gene. The co-existence of beta-lactam and fluoroquinolone resistance markers observed in this study is consistent with widespread use of these antimicrobial agents in Nigeria. The presence of multidrug resistant isolates is concerning and highlights the importance of continued surveillance to support antimicrobial stewardship programs and curb the spread of antimicrobial resistance.202337999619
107390.9999Occurrence of Extended Spectrum Cephalosporin-, Carbapenem- and Colistin-Resistant Gram-Negative Bacteria in Fresh Vegetables, an Increasing Human Health Concern in Algeria. The aim of this study was to screen for extended spectrum cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacteria in fresh vegetables in Batna, Algeria. A total of 400 samples of fresh vegetables were collected from different retail stores. Samples were immediately subjected to selective isolation, then the representative colonies were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). Phenotypic and genotypic analyses were carried out in terms of species identification and relative antibiotic resistance. Transferability of the carbapenemase and mcr-bearing plasmids was verified by conjugation. The clonal relationships of carbapenemase and mcr-positive Escherichia coli isolates were studied by multi-locus sequence typing (MLST). Sixty-seven isolates were characterised and were mostly isolated from green leafy vegetables, where the dominant species identified included Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae, Stenotrophomona maltophilia, E. coli and Citrobacter braakii. PCR and sequencing results showed that E. coli was the bacterial species presenting the highest antibiotic resistance level in parallel to bla(TEM) (n = 16) and bla(CTX-M-15) (n = 11), which were the most detected genes. Moreover, five isolates carried carbapenemase genes, including the bla(OXA-48) and/or bla(VIM-4) genes. The mcr-1 gene was detected in two E. coli isolates. MLST analysis revealed three different E. coli sequence types: ST101 (n = 1), ST216 (n = 1) and ST2298 (n = 1). Conjugation assays confirmed the transferability of the bla(OXA-48) and mcr-1 genes. In this study we report, for the first time, the detection of the bla(OXA-48) gene in E. coli and C. braakii isolates and the bla(VIM-4) gene in vegetables. To the best of our knowledge, this is the first report on the detection of mcr-1 genes from vegetables in Algeria.202235892378
2126100.9999Carbapenemase genes among multidrug resistant gram negative clinical isolates from a tertiary hospital in Mwanza, Tanzania. The burden of antimicrobial resistance (AMR) is rapidly growing across antibiotic classes, with increased detection of isolates resistant to carbapenems. Data on the prevalence of carbapenem resistance in developing countries is limited; therefore, in this study, we determined the prevalence of carbapenemase genes among multidrug resistant gram negative bacteria (MDR-GNB) isolated from clinical specimens in a tertiary hospital in Mwanza, Tanzania. A total of 227 MDR-GNB isolates were analyzed for carbapenem resistance genes. For each isolate, five different PCR assays were performed, allowing for the detection of the major carbapenemase genes, including those encoding the VIM-, IMP-, and NDM-type metallo-beta-lactamases, the class A KPC-type carbapenemases, and the class D OXA-48 enzyme. Of 227 isolates, 80 (35%) were positive for one or more carbapenemase gene. IMP-types were the most predominant gene followed by VIM, in 49 (21.59%) and 28 (12%) isolates, respectively. Carbapenemase genes were most detected in K. pneumoniae 24 (11%), followed by P. aeruginosa 23 (10%), and E. coli with 19 isolates (8%). We have demonstrated for the first time a high prevalence of MDR-GNB clinical isolates having carbapenem resistance genes in Tanzania. We recommend routine testing for carbapenem resistance among the MDR-GNB particularly in systemic infections.201424707481
922110.9999Insertion Sequences within Oxacillinases Genes as Molecular Determinants of Acinetobacter baumannii Resistance to Carbapenems-A Pilot Study. Carbapenem-resistant Acinetobacter baumannii is one of the major problems among hospitalized patients. The presence of multiple virulence factors results in bacteria persistence in the hospital environment. It facilitates bacterial transmission between patients, causing various types of infections, mostly ventilator-associated pneumonia and wound and bloodstream infections. A. baumannii has a variable number of resistance mechanisms, but the most commonly produced are carbapenem-hydrolyzing class D β-lactamases (CHDLs). In our study, the presence of bla(OXA-23), bla(OXA-40) and bla(OXA-51) genes was investigated among 88 clinical isolates of A. baumannii, including 53 (60.2%) strains resistant to both carbapenems (meropenem and imipenem) and 35 (39.8%) strains susceptible to at least meropenem. Among these bacteria, all the isolates carried the bla(OXA-51) gene. The bla(OXA-23) and bla(OXA-40) genes were detected in two (5.7%) and three (8.6%) strains, respectively. Among the OXA-23 carbapenemase-producing A. baumannii strains (n = 55), insertion sequences (ISAba1) were detected upstream of the bla(OXA-23) gene in fifty-two (94.5%) carbapenem-resistant and two (3.6%) meropenem-susceptible isolates. A. baumannii clinical strains from Poland have a similar antimicrobial resistance profile as those worldwide, with the presence of ISAba1 among bla(OXA-23)-positive isolates also being quite common. Carbapenem resistance among A. baumannii strains is associated with the presence of CHDLs, especially when insertion sequences are present.202439458366
1072120.9999Characterization of carbapenem-resistant gram-negative bacterial isolates from Nigeria by whole genome sequencing. This study characterized the mechanisms of carbapenem resistance in gram-negative bacteria isolated from patients in Yola, Nigeria. Whole genome sequencing (WGS) was performed on 66 isolates previously identified phenotypically as carbapenem-non-susceptible. The patterns of beta-lactamase resistance genes identified were primarily species-specific. However, bla(NDM-7) and bla(CMY-4) were detected in all Escherichia coli and most Providencia rettgeri isolates; bla(NDM-7) was also detected in 1 Enterobacter cloacae. The E. coli and E. cloacae isolates also shared bla(OXA-1,) while bla(OXA-10) was found in all P. rettgeri, one Pseudomonas aeruginosa and 1 E. coli. Except for Stenotrophomonas maltophilia isolates, which only contained bla(L1), most species carried multiple beta-lactamase genes, including those encoding extended-spectrum beta-lactamases, AmpC and OXA in addition to a carbapenemase gene. Carbapenemase genes were either class B or class D beta-lactamases. No carbapenemase gene was detected by WGS in 13.6% of isolates.202134111650
886130.9998Detection of Plasmid-Mediated Resistance against Colistin in Multi-Drug-Resistant Gram-Negative Bacilli Isolated from a Tertiary Hospital. The aim of this study was to determine the prevalence of plasmid-mediated colistin resistance mcr-1 to mcr-5 genes among colistin and multi-drug-resistant Gram-negative bacilli strains isolated from patients in a tertiary hospital in Toluca, Mexico. The presence of mcr genes among the 241 strains collected was assessed by PCR. In the case of mcr-carrying E. coli, further PCR tests were performed to determine the presence of bla(CTX-M) and whether the strains belonged to the O25b-ST131 clone. Conjugation experiments were also carried out to assess the horizontal transmission of colistin resistance. A total of twelve strains (5.0%), of which four were E. coli; four were P. aeruginosa; three were K. pneumoniae, and one E. cloacae, were found to be resistant to colistin. Of these strains, two E. coli isolates were found to carry mcr-1, and Southern blot hybridization demonstrated its presence on an approximately 60 kb plasmid. Both mcr-1-carrying E. coli strains were found to co-express bla(CTX-M), belong to the O25b-ST131 clone, and horizontally transmit their colistin resistance. The results of this study confirm the presence of plasmid-mediated colistin resistance in hospitalized patients in Mexico and demonstrated that the multi-drug-resistant O25b-ST131 E. coli clone can acquire mcr genes and transmit such resistance traits to other bacteria.202337630556
1051140.9998Multi-drug Resistance, β-Lactamases Production, and Coexistence of bla (NDM-1) and mcr-1 in Escherichia coli Clinical Isolates From a Referral Hospital in Kathmandu, Nepal. The ability of pathogenic Escherichia coli to produce carbapenemase enzymes is a characteristic that allows them to resist various antibiotics, including last-resort antibiotics like colistin and carbapenem. Our objectives were to identify rapidly developing antibiotic resistance (AR), assess β-lactamases production, and detect mcr-1 and bla (NDM-1) genes in the isolates. A prospective cross-sectional study was carried out in a referral hospital located in Kathmandu from November 2019 to December 2020 using standard laboratory and molecular protocols. Among 77 total E. coli isolates, 64 (83.1%) of them were categorized as MDR. Phenotypically 13 (20.3%) colistin-resistant, 30 (46.9%) ESBL and 8 (12.5%) AmpC producers, and 5 (7.8%) ESBL/AmpC co-producers were distributed among MDR-E. coli. Minimum inhibitory concentrations (MIC) against the majority of MDR isolates were exhibited at 1 g/L. Of these 77 E. coli isolates, 24 (31.2%) were carbapenem-resistant. Among these carbapenem-resistant bacteria, 11 (45.9%) isolates were reported to be colistin-resistant, while 15 (62.5%) and 2 (8.3%) were MBL and KPC producers, respectively. Out of 15 MBL producers, 6 (40%) harbored bla (NDM-1), and 8 (61.5%) out of 13 colistin-resistant pathogens possessed mcr-1. The resistance by colistin- and carbapenem were statistically associated (P < .001). However, only 2 (18.2%) of the co-resistant bacteria were found to have both genes. Our study revealed the highly prevalent MDR and the carbapenem-resistant E. coli and emphasized that the pathogens possess a wide range of capabilities to synthesize β-lactamases. These findings could assist to expand the understanding of AR in terms of enzyme production.202336741474
917150.9998Virulence characterization and clonal analysis of uropathogenic Escherichia coli metallo-beta-lactamase-producing isolates. BACKGROUND: Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract infection (UTI); however, treatment of UTI has been challenging due to increased antimicrobial resistance (AMR). One of the most important types of AMR is carbapenem resistance (CR). CR bacteria are known as an important threat to global public health today. Class B metallo-beta-lactamases (MBLs) are one of the major factors for resistance against carbapenems. We aimed to investigate the characteristics of UPEC isolates producing MBL. METHODS: A cross-sectional study was conducted from October 2018 to December 2019 in Ahvaz; Iran. UPEC isolates were identified by biochemical and molecular methods. Metallo-beta-lactamase-producing isolates were detected using modified carbapenem inactivation method (mCIM) and EDTA-CIM (eCIM) tests. MBL genes, phylogenetic group, and virulence genes profile of carbapenem resistant isolates were determined. Conjugation assay and plasmid profiling were conducted to evaluate the ability of transferring of CR to other E. coli isolates. Clonal similarity of isolates were assessed using Enterobacterial intergenic repetitive element sequence (ERIC)-PCR. RESULTS: Among 406 UPEC isolates, 12 (2.95%) carbapenem-resistant were detected of which 11 were phenotypically MBL-producing strains. Four isolates were resistant to all investigated antimicrobial agents and were considered possible pandrug-resistant (PDR). bla(NDM), bla(OXA-48), bla(IMP-1), and bla(IMP-2) genes were found in 9, 5, 1, and 1 isolates, respectively. Among 30 virulence genes investigated, the traT, fyuA followed by fimH, and iutA with the frequency of 8 (66.7%), 8 (66.7%), 7 (58.3%), and 7 (58.3%) were the most identified genes, respectively. Siderophore production was the main virulence trait among carbapenem-resistant UPEC isolates. Except for two, all other isolates showed weak to moderate virulence index. In all recovered isolates, CR was readily transmitted via plasmids to other isolates during conjugation experiments. CONCLUSION: MBL and carbapenemase genes, especially bla(NDM) and bla(OXA-48) are spreading rapidly among bacteria, which can be a threat to global public health. Therefore monitoring the emergence and dissemination of new AMR is necessary to continuously refine guidelines for empiric antimicrobial therapy. Understanding the mechanisms of resistance and virulence in this group of bacteria can play an effective role in providing new therapeutic methods.202134344363
1447160.9998Molecular detection of β-lactamase and integron genes in clinical strains of Klebsiella pneumoniae by multiplex polymerase chain reaction. INTRODUCTION: Infections caused by β-lactamase-producing gram-negative bacteria, such as Klebsiella pneumoniae, are increasing globally with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the prevalence of antibiotic resistance genes (β-lactamase and integron genes) using multiplex PCR. METHODS: One-hundred K. pneumoniae isolates were collected from different clinical samples. Antibiotic susceptibility testing was performed with thirteen different antibiotics. Multiplex-PCR was used to detect β-lactamase (bla TEM, bla CTX-M, bla SHV , bla VEB, bla PER, bla GES, bla VIM, bla IMP, bla OXA, and bla KPC) and integron genes (int I, int II, and int III). RESULTS: The highest and lowest rate of resistance was exhibited against amikacin (93%) and imipenem (8%), respectively. The frequency of β-lactamase-positive K. pneumoniae was 37%, and the prevalence of the bla TEM, bla CTX-M, bla SHV , bla VEB, bla PER, bla GES, bla VIM, bla IMP, bla OXA, and bla KPC genes was 38%, 24%, 19%, 12%, 6%, 11%, 33%, 0%, 28%, and 23%, respectively. Of the 100 isolates, eight (8%) were positive for class I integrons; however, class II and III integrons were not detected in any of the strains. CONCLUSIONS: These results indicate co-carriage of a number of β-lactamase genes and antibiotic resistance integrons on the same plasmids harboring multi-drug resistance genes. It seems that these properties help to decrease treatment complications due to resistant bacterial infections by rapid detection, infection-control programs and prevention of transmission of drug resistance.201728700049
901170.9998Emergence of plasmid-borne bla (oxa-181) gene in Ochrobactrum intermedium: first report from India. Wastewater has become a potential habitat for multi-drug-resistant bacteria. The present study aims to screen for the presence of carbapenem-resistant bacteria in sewage water samples collected from hospital and non-hospital sources. From a total of 19 sewage water samples collected, 100 carbapenem-resistant non-lactose-fermenting Gram-negative bacteria (CR-NF-GNB) were isolated using MacConkey agar cultured with 8 mg l(-1) of meropenem. On screening for beta-lactamase resistance genes (bla (NDM), bla (OXA-48-like), bla (IMP), bla (VIM) and bla (KPC)), one isolate, Ochrobactrum intermedium , was found to carry the plasmid-borne bla (OXA-48-like) gene. To the best of our knowledge, we provide the first report of the rare and emerging opportunistic pathogen Ochrobactrum intermedium encoding the OXA-181 gene in its plasmid.201932974517
913180.9998Intestinal carriage of colistin-resistant Enterobacteriaceae at Saint Georges Hospital in Lebanon. OBJECTIVES: The increase in resistance to antibiotics has led to the revival of colistin as the last option for treatment, which automatically led to an increase of colistin-resistant, Gram-negative bacteria. In this study, we report the presence of clinical colistin-resistant Enterobacteriaceae isolated from a Lebanese hospital. METHODS: From 23 rectal swabs, eight colistin-resistant clinical strains (five Escherichia coli, two Enterobacter cloacae, and one Klebsiella pneumoniae) were isolated. Antibiotic susceptibility testing was performed using the disk diffusion method and Etest. The broth microdilution method was used to determine colistin susceptibility. Reverse transcription polymerase chain reaction (RT-PCR), standard PCR and sequencing were used to investigate genes encoding for extended-spectrum β-lactamases, carbapenemases and colistin resistance. Genotyping of these isolates was conducted by multilocus sequence typing (MLST). RESULTS: Results of antibiotic susceptibility testing revealed that all isolates were resistant to colistin. They had MICs for colistin that ranged from 8 to 32 mg/L. Real-time PCR results showed that five strains harboured bla(TEM-1) and one strain harboured bla(TEM-163). Moreover, four strains were positive for bla(CTX-M-15), bla(CTX-M-103) and bla(CTX-M-189), and K. pneumoniae harboured bla(SHV-1). Observed colistin resistance was linked to amino acid substitutions into protein sequences of pmrA/B, phoP/Q, and mgrB. Interestingly, we report here a mutation in the mgrB regulator and pmrA/B, phoP/Q in colistin-resistant E. cloacae and E. coli clinical isolates for the first time in Lebanon. CONCLUSION: This study highlights the presence of colistin-resistant Gram-negative bacteria in a Lebanese hospital, which is worrisome. An urgent strategy needs to be adopted to avoid the spread of such bacteria.202031838239
996190.9998Rapid Detection of New Delhi Metallo-β-Lactamase Gene Using Recombinase-Aided Amplification Directly on Clinical Samples From Children. New Delhi metallo-β-lactamase, a metallo-β-lactamase carbapenemase type, mediates resistance to most β-lactam antibiotics including penicillins, cephalosporins, and carbapenems. Therefore, it is important to detect bla (NDM) genes in children's clinical samples as quickly as possible and analyze their characteristics. Here, a recombinase-aided amplification (RAA) assay, which operates in a single one-step reaction tube at 39°C in 5-15 min, was established to target bla (NDM) genes in children's clinical samples. The analytical sensitivity of the RAA assay was 20 copies, and the various bacterial types without bla (NDM) genes did not amplify. This method was used to detect bla (NDM) genes in 112 children's stool samples, 10 of which were tested positive by both RAA and standard PCR. To further investigate the characteristics of carbapenem-resistant bacteria carrying bla (NDM) in children, 15 carbapenem-resistant bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Citrobacter freundii, Klebsiella oxytoca, Acinetobacter junii, and Proteus mirabilis) were isolated from the 10 samples. Notably, more than one bacterial type was isolated from three samples. Most of these isolates were resistant to cephalosporins, cefoperazone-sulbactam, piperacillin-tazobactam, ticarcillin-clavulanic acid, aztreonam, co-trimoxazole, and carbapenems. bla (NDM) (-) (1) and bla (NDM) (-) (5) were the two main types in these samples. These data show that the RAA assay has potential to be a sensitive and rapid bla (NDM) gene screening test for clinical samples. The common existence of bla (NDM) and multi-drug resistance genes presents major challenges for pediatric treatment.202134367092