Plasmid-mediated quinolone resistance in non-Typhi serotypes of Salmonella enterica. - Related Documents




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88001.0000Plasmid-mediated quinolone resistance in non-Typhi serotypes of Salmonella enterica. BACKGROUND: Serious infections with Salmonella species are often treated with fluoroquinolones or extended-spectrum beta-lactams. Increasingly recognized in Enterobacteriaceae, plasmid-mediated quinolone resistance is encoded by qnr genes. Here, we report the presence of qnr variants in human isolates of non-Typhi serotypes of Salmonella enterica (hereafter referred to as non-Typhi Salmonella) from the United States National Antimicrobial Resistance Monitoring System for Enteric Bacteria. METHODS: All non-Typhi Salmonella specimens from the United States National Antimicrobial Resistance Monitoring System for Enteric Bacteria collected from 1996 to 2003 with ciprofloxacin minimum inhibitory concentrations > or = 0.06 microg/mL (233 specimens) and a subset with minimum inhibitory concentrations < or = 0.03 microg/mL (102 specimens) were screened for all known qnr genes (A, B, and S) by polymerase chain reaction. For isolates with positive results, qnr and quinolone resistance-determining region sequences were determined. Plasmids containing qnr genes were characterized by conjugation or transformation. RESULTS: Conjugative plasmids harboring qnrB variants were detected in 7 Salmonella enterica serotype Berta isolates and 1 Salmonella enterica serotype Mbandaka isolate. The S. Mbandaka plasmid also had an extended-spectrum beta -lactamase. Variants of qnrS on nonconjugative plasmids were detected in isolates of Salmonella enterica serotype Anatum and Salmonella enterica serotype Bovismorbificans. CONCLUSIONS: Plasmid-mediated quinolone resistance appears to be widely distributed, though it is still uncommon in non-Typhi Salmonella isolates from the United States, including strains that are quinolone susceptible by the criteria of the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards). The presence of this gene in non-Typhi Salmonella that causes infection in humans suggests potential for spread through the food supply, which is a public health concern.200616804843
162410.9998Detection of chromosomal and plasmid-mediated mechanisms of colistin resistance in Escherichia coli and Klebsiella pneumoniae from Indian food samples. OBJECTIVES: Numerous previous publications on the detection of bacterial isolates harbouring the mcr-1 gene from animals and humans strongly suggest an underlying route of transmission of colistin resistance via the food chain. The aim of this study was to investigate the presence of colistin-resistant (Col-R) bacteria in Indian food samples and to identify the underlying mechanisms conferring colistin resistance. METHODS: Raw food material, including poultry meat, mutton meat, fish, fruit and vegetables, collected from food outlets in Chennai, India, were processed to identify Col-R bacteria using eosin methylene blue agar supplemented with colistin. Colistin minimum inhibitory concentrations (MICs) were determined by the broth microdilution method. PCR for the mcr-1 and mcr-3 genes was performed on Col-R Escherichia coli and Klebsiella pneumoniae isolates. Mutations in the mgrB gene were analysed in K. pneumoniae isolates. One representative mcr-1-positive E. coli was subjected to whole-genome sequencing. RESULTS: Of 110 food samples tested, 51 (46.4%) were positive for non-intrinsic Col-R Gram-negative bacteria. Three E. coli isolates were found to harbour mcr-1, whereas none were positive for mcr-3. Ten K. pneumoniae isolates had alterations in mgrB, with mutations in four and insertional inactivation in six. CONCLUSION: The presence of Col-R bacteria and the mcr-1 gene in raw food samples further complicates the antimicrobial resistance scenario in India. To the best of our knowledge, this is the first report in the global literature on mgrB mutation and its insertional inactivation conferring Col-R in K. pneumoniae from food samples.201930244040
160920.9998Analysis of Salmonella enterica with reduced susceptibility to the third-generation cephalosporin ceftriaxone isolated from U.S. cattle during 2000-2004. Over the past decade enteric bacteria in Europe, Africa, and Asia have become increasingly resistant to cephalosporin antimicrobial agents. This is largely due to the spread of genes encoding extended-spectrum beta-lactamase (ESBL) enzymes that can inactivate many cephalosporins. Recently, these resistance mechanisms have been identified in Salmonella isolated from humans in the United States. Due to the potential for transmission of resistant bacteria to humans via food animals, Salmonella animal isolates were monitored for ESBL production. During 2000-2004, Salmonella cattle slaughter isolates (n = 3,984) were tested, and 97 (2.4%) of these were found to have decreased susceptibility (minimum inhibitory concentration [MIC] >32 microg/ml) to the third-generation cephalosporin ceftriaxone. The majority of these were serotypes Newport (58) and Agona (14), some of which were genetically indistinguishable by pulsed field gel electrophoresis (PFGE) analysis. None of the isolates had an ESBL phenotype; all were susceptible to the fourth-generation cephalosporins cefepime and cefquinome. PCR and sequence analysis for resistance genes detected the bla(CMY-2) gene in 93 isolates and the bla(TEM-1) gene in 12 isolates; however, neither gene encodes an ESBL. These data indicate that bovine Salmonella isolates from the United States with decreased susceptibility or resistance to ceftriaxone do not exhibit an ESBL phenotype and most contain the bla(CMY-2) gene.200819025468
89530.9998The 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
173240.9998High Carriage Rate of the Multiple Resistant Plasmids Harboring Quinolone Resistance Genes in Enterobacter spp. Isolated from Healthy Individuals. Antimicrobial-resistant bacteria causing intractable and even fatal infections are a major health concern. Resistant bacteria residing in the intestinal tract of healthy individuals present a silent threat because of frequent transmission via conjugation and transposition. Plasmids harboring quinolone resistance genes are increasingly detected in clinical isolates worldwide. Here, we investigated the molecular epidemiology of plasmid-mediated quinolone resistance (PMQR) in Gram-negative bacteria from healthy service trade workers. From 157 rectal swab samples, 125 ciprofloxacin-resistant strains, including 112 Escherichia coli, 10 Klebsiella pneumoniae, two Proteus mirabilis, and one Citrobacter braakii, were isolated. Multiplex PCR screening identified 39 strains harboring the PMQR genes (including 17 qnr,19 aac(6')-Ib-cr, and 22 oqxA/oqxB). The genome and plasmid sequences of 39 and 31 strains, respectively, were obtained by short- and long-read sequencing. PMQR genes mainly resided in the IncFIB, IncFII, and IncR plasmids, and coexisted with 3-11 other resistance genes. The high PMQR gene carriage rate among Gram-negative bacteria isolated from healthy individuals suggests the high-frequency transmission of these genes via plasmids, along with other resistance genes. Thus, healthy individuals may spread antibiotic-resistant bacterial, highlighting the need for improved monitoring and control of the spread of antibiotic-resistant bacteria and genes in healthy individuals.202135052892
86650.9998Opening Pandora's box: High-level resistance to antibiotics of last resort in Gram-negative bacteria from Nigeria. OBJECTIVES: The aim of this study was to determine the percentage of antimicrobial-resistant isolates and the associated resistance mechanisms in Gram-negative bacteria from South Western Nigeria. METHODS: A total of 306 non-duplicate unbiased Gram-negative isolates were recovered from patients admitted to three teaching hospitals in South Western Nigeria in 2011 and 2013. Isolates were from clinical samples as well as from stool samples of inpatients without infection to assess antimicrobial resistance patterns in carriage isolates. Antimicrobial susceptibility testing was performed, and PCR and sequencing were used to identify genes encoding various known β-lactamases. Based on phenotypic and genotypic results, 10 isolates representing the diversity of phenotypes present were selected for whole-genome sequencing (WGS). RESULTS: Antimicrobial susceptibility testing revealed the following resistance rates: fluoroquinolones, 78.1%; third-generation cephalosporins, 92.2%; and carbapenems, 52.6%. More resistant isolates were isolated from stools of uninfected patients compared with clinical infection specimens. Klebsiella (10%) and Escherichia coli (7%) isolates produced a carbapenemase. WGS of selected isolates identified the presence of globally disseminated clones. CONCLUSION: This study illustrates a crisis for the use of first-line antimicrobial therapy in Nigerian patients. It is likely that Nigeria is playing a significant role in the spread of antimicrobial resistance owing to its large population with considerable global mobility.202031654790
89260.9998Sequencing analysis of tigecycline resistance among tigecycline non-susceptible in three species of G-ve bacteria isolated from clinical specimens in Baghdad. BACKGROUND: Recent emergence of high-level tigecycline resistance is mediated by tet(X) genes in Gram-negative bacteria, which undoubtedly constitutes a serious threat for public health worldwide. This study aims to identify tigecycline non-susceptible isolates and detect the presence of genes that are responsible for tigecycline resistance among local isolates in Iraq for the first time. METHODS: Thirteen clinical isolates of Klebsiella pneumonia, Acinetobacter baumannii and Pseudomonas aeruginosa tigecycline non-susceptible were investigated from blood, sputum and burns specimens. The susceptibility of different antibiotics was tested by the VITEK-2 system. To detect tigecycline resistance genes, PCR was employed. RESULTS: Strains studied in this work were extremely drug-resistant and they were resistant to most antibiotic classes that were studied. The plasmid-encoded tet(X), tet(X1), tet(X2), tet(X3), tet(X4), tet(X5), tet(M) and tet(O) genes were not detected in the 13 isolates. The results showed that there is a clear presence of tet(A) and tet(B) genes in tigecycline non-susceptible isolates. All 13 (100%) tigecycline non-susceptible K. pneumoniae, A. baumannii and P. aeruginosa isolates harbored the tet(B) gene. In contrast, 4 (30.77%) tigecycline non-susceptible P. aeruginosa isolates harbored the tet(A) gene and there was no tigecycline non-susceptible A. baumannii isolate harboring the tet(A) gene (0%), but one (7.69%) tigecycline non-susceptible K. pneumoniae isolate harbored the tet(A) gene. A phylogenetic tree, which is based on the nucleotide sequences of the tet(A) gene, showed that the sequence of the local isolate was 87% similar to the nucleotide sequences for all the isolates used for comparison from GenBank and the local isolate displayed genetic diversity. CONCLUSIONS: According to this study, tet(B) and tet(A) play an important role in the appearance of tigecycline non-susceptible Gram-negative isolates.202236207501
168470.9998Plasmid-encoded gene duplications of extended-spectrum β-lactamases in clinical bacterial isolates. INTRODUCTION: The emergence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is an urgent and alarming One Health problem. This study aimed to investigate duplications of plasmid-encoded ESBL genes and their impact on antimicrobial resistance (AMR) phenotypes in clinical and screening isolates. METHODS: Multi-drug-resistant bacteria from hospitalized patients were collected during routine clinical surveillance from January 2022 to June 2023, and their antimicrobial susceptibility patterns were determined. Genotypes were extracted from long-read whole-genome sequencing data. Furthermore, plasmids and other mobile genetic elements associated with ESBL genes were characterized, and the ESBL genes were correlated to ceftazidime minimal inhibitory concentration (MIC). RESULTS: In total, we identified four cases of plasmid-encoded ESBL gene duplications that match four genetically similar plasmids during the 18-month surveillance period: five Escherichia coli and three Klebsiella pneumoniae isolates. As the ESBL genes were part of transposable elements, the surrounding sequence regions were duplicated as well. In-depth analysis revealed insertion sequence (IS)-mediated transposition mechanisms. Isolates with duplicated ESBL genes exhibited a higher MIC for ceftazidime in comparison to isolates with a single gene copy (3-256 vs. 1.5-32 mg/L, respectively). CONCLUSION: ESBL gene duplications led to an increased phenotypic resistance against ceftazidime. Our data suggest that ESBL gene duplications by an IS-mediated transposition are a relevant mechanism for how AMR develops in the clinical setting and is part of the microevolution of plasmids.202438469349
205380.9997Replicon typing of plasmids in environmental Achromobacter sp. producing quinolone-resistant determinants. This study aimed to investigate the antimicrobial resistance profile to quinolones, the presence of quinolone-resistant determinants and the plasmid replicon typing in environmental Achromobacter sp. isolated from Brazil. Soil and water samples were used for bacterial isolation. The antimicrobial susceptibility testing was performed by minimum inhibitory concentration method. The detection of mutations in the quinolone resistance-determining regions (QRDR) genes, the presence of plasmid-mediated quinolone resistance (PMQR) genes, and plasmid replicons were performed by PCR. A total of 16 isolates was obtained from different cultures, cities, and states of Brazil. All isolates were non-susceptible to ciprofloxacin, norfloxacin, and levofloxacin. Some mutations in QRDR genes were found, including Gln-83-Leu and Asp-87-Asn in the gyrA and Gln-80-Ile and Asp-84-Ala in the parC. Different PMQR genes were detected, such as qnrA, qnrB, qnrS, oqxA, and oqxB. Three different plasmid families were detected, being most presented the ColE-like, followed by IncFIB and IncA/C. The presence of different PMQR genes and plasmids in the isolates of the present study shows that environmental bacteria can act as reservoir of important genes of resistance to fluoroquinolones, which is of great concern, due to the potential of horizontal dissemination of these genes. Besides that, there are no studies reporting these results in Achromobacter sp. isolates.201830357960
162590.9997Colistin-resistant Escherichia coli carrying mcr-1 in food, water, hand rinse, and healthy human gut in Bangladesh. BACKGROUND: One of the most significant public health concerns in today's world is the persistent upsurge of infections caused by multidrug resistant bacteria. As a result, clinicians are being forced to intervene with either less effective backup drugs or ones with substantial side-effects. Colistin is a last resort antimicrobial agent for the treatment of infections caused by multi-drug resistant gram-negative bacteria. METHODS: Escherichia coli (n = 65) isolated from street food (n = 20), hand rinse (n = 15), surface water (n = 10), and healthy human stool (n = 20) were tested for colistin resistance gene mcr-1 and response to antimicrobial agents. Antimicrobial resistance genes and virulence genes were detected by employing polymerase chain reaction. DNA fingerprinting of the strains were determined by pulsed-field gel electrophoresis. RESULTS: Screening of E. coli allowed us to confirm colistin resistance marker gene mcr-1 in 13 strains (street food, n = 4; hand rinse, n = 2; surface water, n = 4; and stool, n = 3); and two of these E. coli strains carrying mcr-1 harbored bla (TEM) gene encoding extended spectrum beta lactamase. Antibiotic assay results revealed all 13 E. coli strains carrying mcr-1 to be multi-drug resistant (MDR), including to colistin. The minimum inhibitory concentration (MIC) for colistin ranged from 2 to 6 μg/ml. DNA sequencing confirmed homogeneity of the nucleotide sequence for mcr-1, but the E. coli strains were heterogenous, as confirmed by pulsed-field gel electrophoresis suggesting horizontal transmission of colistin resistance in Bangladesh. CONCLUSION: Widespread dissemination of E. coli strains carrying mcr-1 encoding resistance to colistin in the present study is alarming as this is the last resort drug for the treatment of infections caused by MDR gram-negative bacteria resistant to almost all drugs used commonly.202032002025
2045100.9997Molecular characterization of multidrug-resistant Shigella species isolated from epidemic and endemic cases of shigellosis in India. Shigella species represent one of the growing numbers of antimicrobial-resistant bacteria in developing countries. Fluoroquinolone-resistant strains of Shigella dysenteriae type 1 and Shigella flexneri type 2a emerged in India during 2002 and 2003, respectively. Sixty strains of Shigella from different parts of India were analysed for antimicrobial susceptibility, the presence of the qnr plasmid, mutations in the quinolone resistance determining regions (QRDRs), fluoroquinolone accumulation, and the presence of other genes encoding resistance to various antimicrobials. Fluoroquinolone-resistant strains had mutations in gyrA and parC genes and had an active efflux system. They were also resistant to several other antimicrobials but were susceptible to azithromycin and ceftriaxone. The majority of the strains harboured genes encoding resistance to ampicillin (97 %), tetracycline (95 %), streptomycin (95 %) and chloramphenicol (94 %). PFGE analysis revealed clonality among strains of S. dysenteriae types 1 and 5, S. flexneri type 2a and Shigella boydii type 12.200818566144
1735110.9997Multiple transmissible genes encoding fluoroquinolone and third-generation cephalosporin resistance co-located in non-typhoidal Salmonella isolated from food-producing animals in China. The aim of this study was to identify genes conferring resistance to fluoroquinolones and extended-spectrum β-lactams in non-typhoidal Salmonella (NTS) from food-producing animals in China. In total, 31 non-duplicate NTS were obtained from food-producing animals that were sick. Isolates were identified and serotyped and the genetic relatedness of the isolates was determined by pulsed-field gel electrophoresis of XbaI-digested chromosomal DNA. Antimicrobial susceptibility was determined using Clinical and Laboratory Standards Institute methodology. The presence of extended-spectrum β-lactamase (ESBL) and fluoroquinolone resistance genes was established by PCR and sequencing. Genes encoded on transmissible elements were identified by conjugation and transformation. Plasmids were typed by PCR-based replicon typing. The occurrence and diversity of numerous different transmissible genes conferring fluoroquinolone resistance [qnrA, qnrD, oqxA and aac(6')-Ib-cr] and ESBLs (CTX-M-27 and CTX-M-14), and which co-resided in different isolates and serovars of Salmonella, were much higher than in European countries. Furthermore, different plasmids encoded fluoroquinolone resistance (ca. 6 kb) and β-lactam resistance (ca. 63 kb) and these co-resided in isolates with mutations in topoisomerase genes (gyrA and parC) giving very resistant Salmonella. The presence of multidrug-resistant bacteria in food-producing animals in countries that export foodstuffs suggests that global transfer of antibiotic resistances from country to country on food is possible.201424581597
883120.9997Detection of plasmid-mediated colistin resistance, mcr-1 gene, in Escherichia coli isolated from high-risk patients with acute leukemia in Spain. BACKGROUND: Bacterial infections in immunocompromised patients are associated with a high mortality and morbidity rate. In this high-risk group, the presence of multidrug-resistant (MDR) bacteria, particularly bacteria that harbor a transferable antibiotic resistance gene, complicates the management of bacterial infections. In this study, we investigated the presence of the transferable colistin resistance mcr genes in patients with leukemia in Spain. METHODS: 217 fecal samples collected in 2013-2015 from 56 patients with acute leukemia and colonized with MDR Enterobacteriaceae strains, were screened on September 2017 for the presence of the colistin resistance mcr genes (mcr-1 to -5) by multiplex PCR. mcr positive strains selected on LBJMR and MacConkey supplemented with colistin (2 μg/ml) media were phenotypically and molecularly characterized by antimicrobial susceptibility testing, minimum inhibitory concentration, multilocus sequence typing and plasmid characterization. RESULTS: Among 217 fecal samples, 5 samples collected from 3 patients were positive for the presence of the mcr-1 colistin-resistance gene. Four Escherichia coli strains were isolated and exhibited resistance to colistin with MIC = 4 μg/ml. Other genes conferring the resistance to β-lactam antibiotics have also been identified in mcr-1 positive strains, including bla(TEM-206) and bla(TEM-98). Three different sequence types were identified, including ST1196, ST140 and ST10. Plasmid characterization allowed us to detect the mcr-1 colistin resistance gene on conjugative IncP plasmid type. CONCLUSION: To the best of our knowledge, we have identified the mcr-1 gene for the first time in leukemia patients in Spain. In light of these results, strict measures have been implemented to prevent its dissemination.201931023570
1713130.9997Conjugative plasmidic AmpC detected in Escherichia coli, Proteus mirabilis and Klebsiella pneumoniae human clinical isolates from Portugal. AmpC is a type of β-lactamase enzyme produced by bacteria; these enzymes are classified in Class C and Group 1, and these confer resistance to cephamycin. Enterobacterales producing AmpC are reported worldwide and have great clinical importance due to therapeutic restriction and epidemiological importance once the easy dissemination by plasmidic genes to other bacteria is a real threat. These genes are naturally found in some enterobacteria as Enterobacter cloacae, Morganella morganii, and Citrobacter freundii, but other species have demonstrated similar resistance phenotype of AmpC production. Genes carried in plasmids have been described in these species conferring resistance to cefoxitin and causing therapeutic failure in some bacterial infections. This work detected and described five clinical strains of Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae that presented plasmid ampC (pAmpC) isolated from the north of Portugal collected in 2009. AmpC production was confirmed by inhibition of the enzyme by cloxacillin and boronic acid in agar diffusion tests. Also, PCR (polymerase chain reaction) was performed for the detection of gene universal to AmpC, bla(ampC), and others to AmpC group: bla(ACC), bla(CIT), bla(CMY), bla(DHA), and bla(EBC). The conjugation in liquid medium for 24 h was realized to determine if gene is localized in chromosome or plasmid. The isolates and their conjugants showed phenotypic characteristics and bla(CMY) and bla(CIT) were detected by PCR corroborating the AmpC characteristics observed in these bacteria. Confirmation of transfer of plasmid containing genes encoding AmpC is of high epidemiological relevance to the hospital studied and demonstrated the importance of AmpC surveillance and studies in hospital and community environments in order to choose the appropriate therapy for bacterial infections.202032740783
864140.9997Prevalence and molecular characterization of β-lactamase producers and fluoroquinolone resistant clinical isolates from North East India. INTRODUCTION: The rapid emergence and variations of antibiotic resistance among common gram negative bacteria cause a significant concern specially in India and all over the world because of high mortality and morbidity rates. METHODS: In our study, we screened 189 bacterial isolates from Assam Medical College & Hospital, Dibrugarh for antibiotic resistance pattern and tried to identify the resistant genes causing responsible for β-lactam and fluoroquinolones resistance. RESULTS: More than 80% and 45% strains were resistant to all the 3rd generation cephalosporins, fluoroquinolones respectively. Among the 3rd generation cephalosporin resistant strains, 38% and 24% isolates were only ESBL and MBL producers respectively and 11% were reported to have both ESBL and MBL genes. The ESBL positive isolates have shown the dominance of CTX-M3 gene. VIM-1 gene was mostly reported in MBL producers. Our study probably for the first time reporting SIM-1 and SPM-1 MBL gene from India. Mutations in QRDR is found to be the primary cause of fluoroquinolone resistance along with efflux pump and PMQR presence. CONCLUSION: The study represents the first detailed study on antibiotic resistance from NE India this could help to take control measures for the emerging antibiotic resistance in hospital and community based infections in North East India.202133848892
1647150.9997Genomic and antimicrobial resistance genes diversity in multidrug-resistant CTX-M-positive isolates of Escherichia coli at a health care facility in Jeddah. BACKGROUND: Whole genome sequencing has revolutionized epidemiological investigations of multidrug-resistant pathogenic bacteria worldwide. Aim of this study was to perform comprehensive characterization of ESBL-positive isolates of Escherichia coli obtained from clinical samples at the King Abdulaziz University Hospital utilizing whole genome sequencing. METHODS: Isolates were identified by MALDI-TOF mass spectrometry. Genome sequencing was performed using a paired-end strategy on the MiSeq platform. RESULTS: Nineteen isolates were clustered into different clades in a phylogenetic tree based on single nucleotide polymorphisms in core genomes. Seventeen sequence types were identified in the extended-spectrum β-lactamase (ESBL)-positive isolates, and 11 subtypes were identified based on distinct types of fimH alleles. Forty-one acquired resistance genes were found in the 19 genomes. The bla(CTX-M-15) gene, which encodes ESBL, was found in 15 isolates and was the most predominant resistance gene. Other antimicrobial resistance genes (ARGs) found in the isolates were associated with resistance to tetracycline (tetA), aminoglycoside [aph(3″)-Ib, and aph(6)-Id], and sulfonamide (sul1, and sul2). Nonsynonymous chromosomal mutations in the housekeeping genes parC and gyrA were commonly found in several genomes. CONCLUSION: Several other ARGs were found in CTX-M-positive E. coli isolates confer resistance to clinically important antibiotics used to treat infections caused by Gram-negative bacteria.202031279801
882160.9997Ceftriaxone-resistant Salmonella enterica serotype typhimurium sequence type 313 from Kenyan patients is associated with the blaCTX-M-15 gene on a novel IncHI2 plasmid. Multidrug-resistant bacteria pose a major challenge to the clinical management of infections in resource-poor settings. Although nontyphoidal Salmonella (NTS) bacteria cause predominantly enteric self-limiting illness in developed countries, NTS is responsible for a huge burden of life-threatening bloodstream infections in sub-Saharan Africa. Here, we characterized nine S. Typhimurium isolates from an outbreak involving patients who initially failed to respond to ceftriaxone treatment at a referral hospital in Kenya. These Salmonella enterica serotype Typhimurium isolates were resistant to ampicillin, chloramphenicol, cefuroxime, ceftriaxone, aztreonam, cefepime, sulfamethoxazole-trimethoprim, and cefpodoxime. Resistance to β-lactams, including to ceftriaxone, was associated with carriage of a combination of blaCTX-M-15, blaOXA-1, and blaTEM-1 genes. The genes encoding resistance to heavy-metal ions were borne on the novel IncHI2 plasmid pKST313, which also carried a pair of class 1 integrons. All nine isolates formed a single clade within S. Typhimurium ST313, the major clone of an ongoing invasive NTS epidemic in the region. This emerging ceftriaxone-resistant clone may pose a major challenge in the management of invasive NTS in sub-Saharan Africa.201525779570
884170.9997Fecal carriage and molecular epidemiology of mcr-1-harboring Escherichia coli from children in southern China. BACKGROUND: The increase of multidrug-resistant Enterobacteriaceae bacteria has led to the reintroduction of colistin for clinical treatments, and colistin has become a last resort for infections caused by multidrug-resistant bacteria. Enterobacteriaceae bacteria carrying the mcr-1 gene are majorly related to colistin resistance, which may be the main reason for the continued increase in the colistin resistance rate of Enterobacteriaceae. The study aimed to investigate the sequence type and prevalence of Escherichia coli (E. coli) harboring the mcr-1 gene in the gut flora of children in southern China. METHODS: Fecal samples (n = 2632) of children from three medical centers in Guangzhou were cultured for E. coli. The mcr-1-harboring isolates were screened via polymerase chain reaction (PCR). The colistin resistance transfer frequency was studied by conjugation experiments. DNA sequencing data of seven housekeeping genes were used for multi-locus sequence typing analysis (MLST). RESULTS: PCR indicated that 21 of the 2632 E. coli (0.80%) isolates were positive for mcr-1; these strains were resistant to colistin. Conjugation experiments indicated that 18 mcr-1-harboring isolates could transfer colistin resistance phenotypes to E. coli J53. MLST analysis revealed that the 21 isolates were divided into 18 sequence types (STs); E. coli ST69 was the most common (14.3%), followed by E. coli ST58 (9.5%). CONCLUSION: These results demonstrate the colonization dynamics and molecular epidemiology of E. coli harboring mcr-1 in the gut flora of children in southern China. The mcr-1 gene can be horizontally transmitted within species; hence, it is necessary to monitor bacteria that harbor mcr-1 in children.202337196369
1630180.9997One Health study of mobile colistin resistance (mcr) in Salmonella enterica in Canada, 2017-2022. Colistin is a last-resort treatment for highly drug-resistant bacterial infections. Of 47,184 Salmonella isolates collected from 2017 to 2022 in Canada from human and animal/food sources, mobile colistin resistance (mcr) variants conferring colistin resistance were detected exclusively in humans (n = 15). These variants were mcr-1.1 (n = 7), mcr-3.1 (n = 5), mcr-3.2 (n = 2), and mcr-1.2 (n = 1). The most common mcr-containing serotypes were I 4,[5],12:i:- (n = 8) and Typhimurium (n = 3). The proportion of Salmonella carrying mcr genes remains low in Canada (0.03%). IMPORTANCE: Colistin can be used in combination with other drugs as salvage therapy for extensively drug-resistant infections. If mobile colistin resistance (mcr) becomes widely disseminated in Enterobacterales, colistin will no longer be an option for salvage therapy in otherwise untreatable infections. While colistin is not commonly used to treat human Salmonella infections, Salmonella represents an important reservoir of mcr genes that may be transmitted to other gram-negative bacteria. Our aim was to determine the occurrence of mcr genes in Salmonella isolates collected from humans, food animals, and retail meats in Canada.202540387317
885190.9997Emergence of Fosfomycin Resistance by Plasmid-Mediated fos Genes in Uropathogenic ESBL-Producing E. coli Isolates in Mexico. Fosfomycin is currently a viable option against urinary tract infections, particularly against extended-spectrum β-lactamases (ESBL)-producing E. coli, due to its unique mechanism of action and its low resistance among bacteria. The objective of this study was to investigate two of the three most common mechanisms of resistance against this antibiotic among 350 ESBL-producing E. coli strains isolated from the urine of Mexican patients. The prevalence of fosfomycin resistance in our study was 10.9% (38/350). Of all resistant isolates analyzed, 23 (60.5%) were identified as fos-producing organisms, with 14 strains carrying fosA3 and 9, fosA1. Additionally, 11 (28.9%) fosfomycin-resistant isolates presented resistance due to impaired antibiotic transport and 8 (21.0%) both mechanisms. No resistance mechanism investigated in the study was found on 12 strains. All 38 confirmed ESBL-producing isolates carried a bla(CTX-M) subtype, 36 (94.5%) belonged to the O25b-ST131 clone, and all of them were able to transfer the fosfomycin resistance trait to recipient strains horizontally. This is the first study in Mexico demonstrating a plasmid-mediated fosfomycin resistance mechanism among clinical E. coli strains. Since our results suggest a strong association among fos and bla(CTX-M) genes and ST131 clones in uropathogenic E. coli, plasmid-mediated fosfomycin resistance should be closely monitored.202236290041