Molecular characterisations of integrons in clinical isolates of Klebsiella pneumoniae in a Chinese tertiary hospital. - Related Documents




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89401.0000Molecular characterisations of integrons in clinical isolates of Klebsiella pneumoniae in a Chinese tertiary hospital. BACKGROUND: Integrons are mobile genetic elements that play an important role in the distribution of antibiotic-resistance genes among bacteria. This study aimed to investigate the distribution of integrons in clinical isolates of Klebsiella pneumoniae and explore the molecular mechanism of integron-mediated multiple-drug resistance in K. pneumoniae. METHODS: Class 1, 2, and 3 integrases were identified by polymerase chain reaction (PCR) among 178 K. pneumoniae clinical isolates. Antibiotic susceptibility was examined by disk-diffusion method. Conjugation experiments were conducted to evaluate the horizontal-transfer capability, and multilocus sequence typing (MLST) assays were conducted to explore the genetic relationships among the isolates. Highly virulent serotypes were identified by PCR from the 44 integron-positive isolates with variable regions. RESULTS: Class1 and 2 integrons were detected in 60.1% and 1.7% of isolates, respectively. One isolate carried both class 1 and 2 integrons. Class 3 integrons were not detected in all 178 isolates. Among the 44 integrons containing variable regions, 39 were located in conjugative plasmids. Dihydrofolate reductase (dfrA) and aminoglycoside adenyltransferase (aad) were found to be the most common in class 1 and 2 integrons. These gene cassettes encoded resistance to trimethoprim and aminoglycosides. Moreover, the association between integron carriage and antibiotic resistance was most significant for aminoglycosides, phenicols, and fluoroquinolones. Among the 44 integron-positive isolates with variable regions, 9 were classified as highly virulent serotypes (k1, k2, k20, and k54). In addition, MLST analysis detected 13 sequence types (STs), with the predominant ones being ST11 and ST15. The eBURST analysis revalued the existence of 11 singleton STs and one group, which is comprised of ST11 and ST437. CONCLUSIONS: The wide diversity of detected integrons suggested that the horizontal transfer by mobile genetic elements played a major role in the distribution of antimicrobial resistance genes, thereby indicating the urgent need to use effective means of avoiding the spread of drug-resistant bacteria.201728111326
189910.9998Characteristics of plasmids in multi-drug-resistant Enterobacteriaceae isolated during prospective surveillance of a newly opened hospital in Iraq. BACKGROUND: Gram-negative multidrug-resistant (MDR) bacteria are major causes of nosocomial infections, and antibiotic resistance in these organisms is often plasmid mediated. Data are scarce pertaining to molecular mechanisms of antibiotic resistance in resource constrained areas such as Iraq. METHODOLOGY/PRINCIPAL FINDINGS: In this study, all MDR Enterobacteriaceae (n = 38) and randomly selected non-MDR counterparts (n = 41) isolated from patients, healthcare workers and environmental surfaces in a newly opened hospital in Iraq were investigated to characterize plasmids found in these isolates and determine their contribution to antibiotic resistance. Our results demonstrated that MDR E. coli and K. pneumoniae isolates harbored significantly more (≥ 3) plasmids compared to their non-MDR counterparts, which carried ≤ 2 plasmids (p<0.01). Various large plasmids (~52 to 100 kb) from representative isolates were confirmed to contain multiple resistance genes by DNA microarray analysis. Aminoglycoside (acc, aadA, aph, strA/B, and ksgA), β-lactam (bla(TEM1), bla(AMPC), bla(CTX-M-15), bla(OXA-1), bla(VIM-2) and bla(SHV)), sulfamethoxazole/trimethoprim (sul/dfr), tetracycline (tet) and chloramphenicol (cat) resistance genes were detected on these plasmids. Additionally, multiple plasmids carrying multiple antibiotic resistance genes were found in the same host strain. Genetic transfer-associated genes were identified on the plasmids from both MDR and non-MDR isolates. Seven plasmid replicon types (FII, FIA, FIB, B/O, K, I1 and N) were detected in the isolates, while globally disseminated IncA/C and IncHI1 plasmids were not detected in these isolates. CONCLUSIONS/SIGNIFICANCE: This is the first report of the characteristics of the plasmids found in Enterobacteriaceae isolated following the opening of a new hospital in Iraq. The information provided here furthers our understanding of the mechanisms of drug resistance in this specific region and their evolutionary relationship with other parts of world. The large plasmids, carrying resistance genes and transfer-associated genes, may be potential factors for regional dissemination of antibiotic resistance.201222808141
89620.9998Retrospective Screening and Analysis of mcr-1 and bla (NDM) in Gram-Negative Bacteria in China, 2010-2019. Currently, Gram-negative bacteria have developed multidrug and broad-spectrum drug resistance, and the numbers of species and strains carrying mcr or bla (NDM) genes are increasing. In this study, mcr-1 and bla (NDM) distribution of 12,858 Gram-negative bacteria isolated from wildlife, patients, livestock, poultry and environment in 14 provinces of China from 2010 to 2019 and the antibiotics resistance in regard to polymyxins (polymyxin B and colistin) and carbapenems of positive strains were investigated. A total of 70 strains of 10 species carried the mcr-1 gene, positive rates of patients, livestock and poultry, and environmental strains were 0.62% (36/5,828), 4.07% (29/712), 5.43% (5/92), respectively. Six strains of 3 species carrying the bla (NDM) gene all came from patients 0.10% (6/5,828). Two new mcr-1 gene variants (GenBank: MK965883, MK965884) were identified, one of which contains premature stop codon. The drug susceptibility results showed that all mcr-1 carriers were sensitive to carbapenems, among which, 66 strains were resistant and 4 were sensitive to polymyxins. The strains with the bla (NDM) gene had different degrees of resistance to carbapenems and were sensitive to polymyxins. The findings that species carrying mcr-1 or bla (NDM) genes were limited and mostly normal flora of opportunistic or low pathogenic organisms indicated that transfer of mcr-1 and bla (NDM) genes between bacteria was relatively limited in China. The none detection among wildlife compared with other sources supports the speculation that the emergence of and increase in polymyxins and carbapenem-resistant strains was mainly related to the selective pressure of antibiotics.202032117144
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
89740.9998Prevalence 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
88750.9998Characterization of fosfomycin resistance and molecular epidemiology among carbapenem-resistant Klebsiella pneumoniae strains from two tertiary hospitals in China. BACKGROUND: Fosfomycin has been proven to be a vital choice to treat infection caused by multidrug resistance bacteria, especially carbapenem-resistant Klebsiella pneumoniae (CRKP). However, fosfomycin resistant cases has been reported gradually. In this study, we reported the fosfomycin-resistant rate in CRKP strains and further revealed the molecular mechanisms in resistance gene dissemination. RESULTS: A total of 294 non-duplicated CRKP strains were collected. And 55 fosfomyin-resistant strains were detected, 94.5% of which were clustered to sequence type (ST) 11 by PCR followed up sequencing. PFGE further revealed two major groups and four singletons. The positive rates of genes responsible to fosfomycin and carbapenem resistance were 81.8% (fosA3), 12.7% (fosA5) and 94.5% (bla(KPC-2)), respectively. Genomic analysis confirmed insertion sequence (IS) 26 was the predominant structure surrounding fosA3. The fosA3 genes in six isolates were located on plasmids which were able to transfer to E. coli J53 recipient cells by means of conjugation. CONCLUSIONS: Although the resistant rate of CRKP to fosfomycin is relatively low in our area, considering its gene is located on transferrable plasmid and inserted in IS structure, continuous monitoring is still needed.202133838639
173260.9998High 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
96670.9998Classes 1 and 2 integrons in faecal Escherichia coli strains isolated from mother-child pairs in Nigeria. BACKGROUND: Antimicrobial resistance among enteric bacteria in Africa is increasingly mediated by integrons on horizontally acquired genetic elements. There have been recent reports of such elements in invasive pathogens across Africa, but very little is known about the faecal reservoir of integron-borne genes. METHODS AND FINDINGS: We screened 1098 faecal Escherichia coli isolates from 134 mother-child pairs for integron cassettes by PCR using primers that anneal to the 5' and 3' conserved ends of the cassette regions and for plasmid replicons. Genetic relatedness of isolates was determined by flagellin and multi-locus sequence typing. Integron cassettes were amplified in 410 (37.5%) isolates and were significantly associated with resistance to trimethoprim and multiple resistance. Ten cassette combinations were found in class 1 and two in class 2 integrons. The most common class 1 cassette configurations were single aadA1 (23.4%), dfrA7 (18.3%) and dfrA5 (14.4%). Class 2 cassette configurations were all either dfrA1-satI-aadA1 (n = 31, 7.6%) or dfrA1-satI (n = 13, 3.2%). A dfr cassette was detected in 294 (31.1%) of trimethoprim resistant strains and an aadA cassette in 242 (23%) of streptomycin resistant strains. Strains bearing integrons carried a wide range of plasmid replicons of which FIB/Y (n = 169; 41.2%) was the most frequently detected. Nine isolates from five different individuals carried the dfrA17-aadA5-bearing ST69 clonal group A (CGA). The same integron cassette combination was identified from multiple distinct isolates within the same host and between four mother-child pairs. CONCLUSIONS: Integrons are important determinants of resistance in faecal E. coli. Plasmids in integron-containing strains may contribute to dispersing resistance genes. There is a need for improved surveillance for resistance and its mechanisms of dissemination and persistence and mobility of resistance genes in the community and clinical settings.201728829804
96980.9998Dissemination of the rmtB gene carried on IncF and IncN plasmids among Enterobacteriaceae in a pig farm and its environment. OBJECTIVES: To investigate the prevalence and characterization of 16S rRNA methylase-producing bacteria in a pig farm and its environment in East China. METHODS: Enterobacteriaceae isolates and metagenomic DNA from 102 pig faecal samples from a pig farm and 97 soil samples taken in or around the farm were screened for the presence of 16S rRNA methylase genes. The clonal relationships of 16S rRNA methylase-positive isolates, plasmid content and other associated resistance genes were also characterized. RESULTS: Fifty-six rmtB-positive Enterobacteriaceae isolates, including 54 Escherichia coli, 1 Morganella morganii and 1 Proteus mirabilis, were recovered from 55 pig faecal samples. Nineteen rmtB-positive bacteria, including 13 E. coli, 2 M. morganii, 2 Leclercia adecarboxylata, 1 Enterobacter aerogenes and 1 Enterobacter cloacae, were recovered from 16 soil samples. Among the 75 rmtB-positive isolates, 31 and 25 also carried the qepA and bla(CTX-M) genes, respectively. The qepA gene co-localized with rmtB on the F2:A-:B1 plasmids and the bla(CTX-M-65) gene co-localized with rmtB on the F33:A-:B- plasmids. The rmtB gene was also found to be associated with the IncN plasmids. Clonal transmission of rmtB-positive E. coli isolates was observed between different pig groups and soil samples. CONCLUSIONS: Both horizontal gene transfer and clonal spread could be responsible for the dissemination of the rmtB gene in the pig farm and its environment. To our knowledge, this study is the first report of rmtB-positive bacteria from farmland soils and indicates that these antibiotic-resistant bacteria and/or resistance genes could be acquired by humans through the food chain.201121852287
96890.9998Molecular 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
884100.9998Fecal 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
870110.9998Dissemination of multiple carbapenem-resistant clones of Acinetobacter baumannii in the Eastern District of Saudi Arabia. It has previously been shown that carbapenem-resistant Acinetobacter baumannii are frequently detected in Saudi Arabia. The present study aimed to identify the epidemiology and distribution of antibiotic resistance determinants in these bacteria. A total of 83 A. baumannii isolates were typed by pulsed-field gel electrophoresis (PFGE), and screened by PCR for carbapenemase genes and insertion sequences. Antibiotic sensitivity to imipenem, meropenem, tigecycline, and colistin were determined. Eight different PFGE groups were identified, and were spread across multiple hospitals. Many of the PFGE groups contained isolates belonging to World-wide clone 2. Carbapenem resistance or intermediate resistance was detected in 69% of isolates. The bla VIM gene was detected in 94% of isolates, while bla OXA-23-like genes were detected in 58%. The data demonstrate the co-existence and wide distribution of a number of clones of carbapenem-resistant A. baumannii carrying multiple carbapenem-resistance determinants within hospitals in the Eastern Region of Saudi Arabia.201526191044
888120.9998Identification of New Delhi metallo-β-lactamase 1 in Acinetobacter lwoffii of food animal origin. BACKGROUND: To investigate the presence of metallo-β-lactamase (MBL) genes and the genetic environment of the New Delhi metallo-β-lactamase gene bla(NDM-1) in bacteria of food animal origin. METHODOLOGY/PRINCIPAL FINDINGS: Gram-negative bacteria with low susceptibility to imipenem (MIC>8 µg/mL) were isolated from swab samples collected from 15 animal farms and one slaughterhouse in eastern China. These bacteria were selected for phenotypic and molecular detection of known MBL genes and antimicrobial susceptibility testing. For the bla(NDM-1) positive isolate, conjugation and transformation experiments were carried out to assess plasmid transfer. Southern blotting was conducted to localize the bla(NDM-1) genes, and DNA sequencing was performed to determine the sequences of bla(NDM-1) and the flanking genes. In total, nine gram-negative bacteria of four different species presented a MBL phenotype. bla(NDM-1) was identified on a mobile plasmid named pAL-01 in an Acinetobacter lwoffii isolate of chicken origin. Transfer of pAL-01 from this isolate to E. coli J53 and JM109 resulted in resistance to multiple β-lactams. Sequence analysis revealed that the bla(NDM-1) gene is attached to an intact insertion element ISAba125, whose right inverted repeat (IR-R) overlaps with the promoter sequence of bla(NDM-1). Thus, insertion of ISAba125 likely enhances the expression of bla(NDM-1). CONCLUSION: The identification of a bla(NDM-1)- carrying strain of A. lwoffii in chickens suggests the potential for zoonotic transmission of bla(NDM-1) and has important implications for food safety.201222629360
883130.9998Detection 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
1143140.9998Antimicrobial Resistance and Virulence Profiles of mcr-1-Positive Escherichia coli Isolated from Swine Farms in Heilongjiang Province of China. ABSTRACT: The emergence and global distribution of the mcr-1 gene for colistin resistance have become a public concern because of threats to the role of colistin as the last line of defense against some bacteria. Because of the prevalence of mcr-1-positive Escherichia coli isolates in food animals, production of these animals has been regarded as one of the major sources of amplification and spread of mcr-1. In this study, 249 E. coli isolates were recovered from 300 fecal samples collected from swine farms in Heilongjiang Province, People's Republic of China. Susceptibility testing revealed that 186 (74.70%) of these isolates were colistin resistant, and 86 were positive for mcr-1. The mcr-1-positive isolates had extensive antimicrobial resistance profiles and additional resistance genes, including blaTEM, blaCTX-M, aac3-IV, tet(A), floR, sul1, sul2, sul3, and oqxAB. No mutations in genes pmrAB and mgrB were associated with colistin resistance. Phylogenetic group analysis revealed that the mcr-1-positive E. coli isolates belonged to groups A (52.33% of isolates), B1 (33.72%), B2 (5.81%), and D (8.14%). The prevalence of the virulence-associated genes iutA, iroN, fimH, vat, ompA, and traT was moderate. Seven mcr-1-positive isolates were identified as extraintestinal pathogenic. Among 20 mcr-1-positive E. coli isolates, multilocus sequence typing revealed that sequence type 10 was the most common (five isolates). The conjugation assays revealed that the majority of mcr-1 genes were transferable at frequencies of 7.05 × 10-7 to 7.57 × 10-4. The results of this study indicate the need for monitoring and minimizing the further dissemination of mcr-1 among E. coli isolates in food animals, particularly swine.202032730609
1858150.9998Molecular Characteristics of Antimicrobial Resistance and Virulence in Klebsiella pneumoniae Strains Isolated from Goose Farms in Hainan, China. We retrospectively investigated 326 samples that were collected from goose farms in Hainan Province, China, in 2017. A total of 33 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates were identified from 326 samples, and the 33 CRKP isolates were characterized based on whole-genome sequencing (WGS) data from the Illumina and Oxford Nanopore Technologies (ONT) platforms. All of these 33 CRKP isolates possessed bla(NDM-5), and a single isolate coharbored mcr-1 and bla(NDM-5), while 4 isolates carried multiple virulence and metal tolerance gene clusters. One CRKP strain (CMG-35-2) was selected for long sequence reading. A hybrid plasmid carrying the virulence, resistance, and metal resistance gene in the strain was found. It possessed 2 backbones [IncFIB(K)-IncFII(K)] within a single plasmid that were closely related to K. pneumoniae plasmids from a human-associated habitat in the United States and from a human isolate in Hong Kong. A mouse abdominal infection model indicated that that strain was of the moderate virulence phenotype. This study revealed that K. pneumoniae on goose farms is an important reservoir for bla(NDM-5) and these bacteria are represented by a diversity of sequence types. The heterozygous multiple drug resistance genes carried on plasmids highlighted the genetic complexity of CRKP and the urgent need for continued active surveillance. IMPORTANCE CRKP is one of the most important pathogens, which can cause infection not only in humans but also in waterfowl. The discovery of bla(NDM-5)-producing K. pneumoniae in waterfowl farms in recent years suggests that waterfowl are an important reservoir for bla(NDM-5)-producing Enterobacteriaceae. However, there are few studies on the spread of bla(NDM-5)-producing bacteria in waterfowl farms. Our study showed that the IncX3 plasmid carrying bla(NDM-5) in goose farms is widely present in K. pneumoniae isolates and a large number of resistance genes are accumulated in it. We found a transferable IncFIB-FII hybrid plasmid that combines virulence, resistance, and metal resistance genes, which allow transfer of these traits between bacteria in different regions. The results of this study contribute to a better understanding of the prevalence and transmission of carbapenem-resistant K. pneumoniae in goose farms.202235389252
872160.9998Genomic Characterization of Carbapenem-Resistant Bacteria from Beef Cattle Feedlots. Carbapenems are considered a last resort for the treatment of multi-drug-resistant bacterial infections in humans. In this study, we investigated the occurrence of carbapenem-resistant bacteria in feedlots in Alberta, Canada. The presumptive carbapenem-resistant isolates (n = 116) recovered after ertapenem enrichment were subjected to antimicrobial susceptibility testing against 12 different antibiotics, including four carbapenems. Of these, 72% of the isolates (n = 84) showed resistance to ertapenem, while 27% of the isolates (n = 31) were resistant to at least one other carbapenem, with all except one isolate being resistant to at least two other drug classes. Of these 31 isolates, 90% were carbapenemase positive, while a subset of 36 ertapenem-only resistant isolates were carbapenemase negative. The positive isolates belonged to three genera; Pseudomonas, Acinetobacter, and Stenotrophomonas, with the majority being Pseudomonas aeruginosa (n = 20) as identified by 16S rRNA gene sequencing. Whole genome sequencing identified intrinsic carbapenem resistance genes, including blaOXA-50 and its variants (P. aeruginosa), blaOXA-265 (A. haemolyticus), blaOXA-648 (A. lwoffii), blaOXA-278 (A. junii), and blaL1 and blaL2 (S. maltophilia). The acquired carbapenem resistance gene (blaPST-2) was identified in P. saudiphocaensis and P. stutzeri. In a comparative genomic analysis, clinical P. aeruginosa clustered separately from those recovered from bovine feces. In conclusion, despite the use of selective enrichment methods, finding carbapenem-resistant bacteria within a feedlot environment was a rarity.202337370279
892170.9997Sequencing 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
1684180.9997Plasmid-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
868190.9997Antimicrobial susceptibility and genetic characteristics of multi-drug resistant Acinetobacter baumannii isolates in Northwest China. INTRODUCTION: In recent decades, widespread multi-drug resistant (MDR) bacteria have become a serious problem in healthcare facilities. METHODS: To systematically summarize and investigate the prevalence and genomic features of clinical MDR Acinetobacter baumannii (A. baumannii) clinical isolates recovered from the first hospital of Lanzhou University, we collected 50 MDR A. baumannii isolates isolated in the first quarter of 2022 and using whole-genome sequencing investigate the genotypic characteristics. RESULTS: All of these isolates were generally resistant to the common β-lactamase antibiotics. Resistance to cefoperazone-sulbactam varies greatly between different clones. The proportion of CC208 isolates resistant and mediated to cefoperazone-sulbactam is as high as 84.6%. There were no isolates resistant to tigecycline and colistin. The presence of bla(OXA - 23) (94.0%) and bla(OXA - 66) (98.0%) were the most frequent determinants for carbapenem resistance. Two main endemic clones were identified, one (ST469(oxf)) was predominantly circulating in ICUs and carried the same resistance genes, virulence genes and transposons, and the other clone (CC208) carried more resistance genes and had more widely disseminated. DISCUSSION: Our study showed that clinical MDR A. baumannii isolates circulating in our hospital exhibited highly similar genetic features. We should take timely and effective measures to control the further epidemic of these isolates.202438746749