scholarly journals Identification of a Novel Genomic Island Conferring Resistance to Multiple Aminoglycoside Antibiotics in Campylobacter coli

2012 ◽  
Vol 56 (10) ◽  
pp. 5332-5339 ◽  
Author(s):  
Shangshang Qin ◽  
Yang Wang ◽  
Qijing Zhang ◽  
Xia Chen ◽  
Zhangqi Shen ◽  
...  

ABSTRACTHistorically, the incidence of gentamicin resistance inCampylobacterhas been very low, but recent studies reported a high prevalence of gentamicin-resistantCampylobacterisolated from food-producing animals in China. The reason for the high prevalence was unknown and was addressed in this study. PCR screening identified aminoglycoside resistance genesaphA-3andaphA-7and theaadE–sat4–aphA-3cluster among 41Campylobacterisolates from broiler chickens. Importantly, a novel genomic island carrying multiple aminoglycoside resistance genes was identified in 26 aminoglycoside resistantCampylobacter colistrains. Sequence analysis revealed that the genomic island was inserted betweencadFandCOO1582on theC. colichromosome and consists of 14 open reading frames (ORFs), including 6 genes (theaadE–sat4–aphA-3cluster,aacA-aphD,aac, andaadE) encoding aminoglycoside-modifying enzymes. Analysis by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing indicated that theC. coliisolates carrying this unique genomic island were clonal, and the clone of PFGE subtype III and sequence type (ST) 1625 was particularly predominant among theC. coliisolates examined, suggesting that clonal expansion may be involved in dissemination of this resistance island. Additionally, we were able to transfer this genomic island fromC. colito aCampylobacter jejunistrain using natural transformation under laboratory conditions, and the transfer resulted in a drastic increase in aminoglycoside resistance in the recipient strain. These findings identify a previously undescribed genomic island that confers resistance to multiple aminoglycoside antibiotics. Since aminoglycoside antibiotics are used for treating occasional systemic infections caused byCampylobacter, the emergence and spread of this antibiotic resistance genomic island represent a potential concern for public health.

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Hong Yao ◽  
Dejun Liu ◽  
Yang Wang ◽  
Qijing Zhang ◽  
Zhangqi Shen

ABSTRACT Campylobacter is a major foodborne pathogen, and previous studies revealed that Campylobacter isolates from food-producing animals are increasingly resistant to gentamicin in China. The molecular epidemiology and genetic mechanisms responsible for gentamicin resistance in China have not been well understood. In this study, 607 Campylobacter isolates of chicken and swine origins collected in 2014 were analyzed, revealing that 15.6% (25/160) of the Campylobacter jejuni isolates and 79.9% (357/447) of the Campylobacter coli isolates were resistant to gentamicin. PCR detection of the gentamicin resistance genes indicated that aph(2″)-If was more prevalent than the previously identified aacA/aphD gene and has become the dominant gentamicin resistance determinant in Campylobacter. Transformation and whole-genome sequencing as well as long-range PCR discovered that aph(2″)-If was located on a chromosomal segment inserted between two conserved genes, Cj0299 and panB. Cloning of aph(2″)-If into gentamicin-susceptible C. jejuni NCTC 11168 confirmed its function in conferring high-level resistance to gentamicin and kanamycin. Molecular typing by pulsed-field gel electrophoresis suggested that both regional expansion of a particular clone and horizontal transmission were involved in the dissemination of the aph(2″)-If gene in Campylobacter. To our knowledge, this is the first report describing the high prevalence of a chromosomally encoded aph(2″)-If gene in Campylobacter. The high prevalence and predominance of this gene might be driven by the use of aminoglycoside antibiotics in food animal production in China and potentially compromise the usefulness of gentamicin as a therapeutic agent for Campylobacter-associated systemic infection.


2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Xinyi Zhu ◽  
Peizhen Li ◽  
Changrui Qian ◽  
Hongmao Liu ◽  
Hailong Lin ◽  
...  

ABSTRACT Members of the Enterobacter cloacae complex are important opportunistic human pathogens capable of causing a wide variety of infections. During recent decades, aminoglycoside-resistant E. cloacae complex isolates have increasingly been reported and have become a major concern. Here, we employed high-throughput sequencing in combination with specific PCR assays to investigate the prevalence of aminoglycoside resistance genes among 170 isolates of the E. cloacae complex collected from a teaching hospital in Wenzhou, China. A total of 12 known genes [aphA-1, strA, strB, aac(6′)-IIc, aadA2, aac(3)-IId, aadB, aadA1, rmtB, armA, aadA5, and aac(6′)-Ie–aph(2′')-Ia] and 1 novel gene [aac(3)-IIg] were identified, with aphA-1 (71.18%), strA (55.29%), and strB (52.35%) being the most prevalent, and aac(3)-IIg was detected with a positive rate of 21.76% (37/170). The aac(3)-IIg gene was 810 bp in length and encoded a protein that shared 72 to 78% identities with previously known AAC(3)-II aminoglycoside 3-N-acetyltransferases. The MICs of gentamicin and tobramycin were 512 μg/ml and 64 μg/ml, respectively, when aac(3)-IIg was cloned into Escherichia coli DH5α. All aac(3)-IIg-positive isolates exerted broad aminoglycoside resistance profiles, mediated by the coexistence of multiple resistance genes. Moreover, aminoglycoside resistance and resistance genes were found to be transferable in most strains (24/37). Nevertheless, pulsed-field gel electrophoresis (PFGE) and dendrogram analysis showed clonal diversity among these isolates. S1 nuclease PFGE, Southern hybridization, and whole-genome sequencing indicated that aac(3)-IIg was located on transferable as well as nontransferable plasmids of various sizes. The analysis of the genetic environment suggested that aac(3)-IIg is embedded within a class 1 integron, with IS26 playing an important role in its mobility.


2018 ◽  
Vol 62 (3) ◽  
Author(s):  
Shu-Chen Kuo ◽  
Wei-Cheng Huang ◽  
Tzu-Wen Huang ◽  
Hui-Ying Wang ◽  
Jui-Fen Lai ◽  
...  

ABSTRACT The rate of recovery of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates has increased significantly in recent decades in Taiwan. This study investigated the molecular epidemiology of CRAB with a focus on the mechanisms of resistance and spread in isolates with bla OXA-23-like or bla OXA-24-like . All 555 CRAB isolates in our multicenter collection, which were recovered from 2002 to 2010, were tested for the presence of class A, B, and D carbapenemase genes. All isolates with bla OXA-23-like or bla OXA-24-like were subjected to pulsed-field gel electrophoresis, and 82 isolates (60 isolates with bla OXA-23-like and 22 isolates with bla OXA-24-like ) were selected for multilocus sequence typing to determine the sequence type (ST) and clonal group (CG) and for detection of additional β-lactamase and aminoglycoside resistance genes. The flanking regions of carbapenem and aminoglycoside resistance genes were identified by PCR mapping and sequencing. The localization of bla OXA was determined by S1 nuclease and I-CeuI assays. The numbers of CRAB isolates carrying bla OXA-23-like or bla OXA-24-like , especially those carrying bla OXA-23-like , increased significantly from 2008 onward. The bla OXA-23-like gene was carried by antibiotic resistance genomic island 1 (AbGRI1)-type structures located on plasmids and/or the chromosome in isolates of different STs (CG92 and novel CG786), whereas bla OXA-24-like was carried on plasmids in CRAB isolates of limited STs (CG92). No class A or B carbapenemase genes were identified. Multiple aminoglycoside resistance genes coexisted in CRAB. Tn 6180 -borne armA was found in 74 (90.2%) CRAB isolates, and 58 (70.7%) isolates had Tn 6179 upstream, constituting AbGRI3. bla TEM was present in 38 (46.3%) of the CRAB isolates tested, with 35 (92.1%) isolates containing bla TEM in AbGRI2-type structures, and 61% of ampC genes had IS Aba1 upstream. We conclude that the dissemination and spread of a few dominant lineages of CRAB containing various resistance island structures occurred in Taiwan.


2013 ◽  
Vol 57 (11) ◽  
pp. 5398-5405 ◽  
Author(s):  
Yuansha Chen ◽  
Sampa Mukherjee ◽  
Maria Hoffmann ◽  
Michael L Kotewicz ◽  
Shenia Young ◽  
...  

ABSTRACTAminoglycoside resistance inCampylobacterhas been routinely monitored in the United States in clinical isolates since 1996 and in retail meats since 2002. Gentamicin resistance first appeared in a single human isolate ofCampylobacter coliin 2000 and in a single chicken meat isolate in 2007, after which it increased rapidly to account for 11.3% of human isolates and 12.5% of retail isolates in 2010. Pulsed-field gel electrophoresis analysis indicated that gentamicin-resistantC. coliisolates from retail meat were clonal. We sequenced the genomes of two strains of this clone using a next-generation sequencing technique in order to investigate the genetic basis for the resistance. The gaps of one strain were closed using optical mapping and Sanger sequencing, and this is the first completed genome ofC. coli. The two genomes are highly similar to each other. A self-transmissible plasmid carrying multiple antibiotic resistance genes was revealed within both genomes, carrying genes encoding resistance to gentamicin, kanamycin, streptomycin, streptothricin, and tetracycline. Bioinformatics analysis and experimental results showed that gentamicin resistance was due to a phosphotransferase gene,aph(2″)-Ig, not described previously. The phylogenetic relationship of this newly emerged clone to otherCampylobacterspp. was determined by whole-genome single nucleotide polymorphisms (SNPs), which showed that it clustered with the other poultry isolates and was separated from isolates from livestock.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xueya Zhang ◽  
Qiaoling Li ◽  
Hailong Lin ◽  
Wangxiao Zhou ◽  
Changrui Qian ◽  
...  

Aminoglycosides are important options for treating life-threatening infections. However, high levels of aminoglycoside resistance (HLAR) among Klebsiella pneumoniae isolates have been observed to be increasing frequently. In this study, a total of 292 isolates of the K. pneumoniae complex from a teaching hospital in China were analyzed. Among these isolates, the percentage of HLAR strains was 13.7% (40/292), and 15 aminoglycoside resistance genes were identified among the HLAR strains, with rmtB being the most dominant resistance gene (70%, 28/40). We also described an armA-carrying Klebsiella variicola strain KP2757 that exhibited a high-level resistance to all aminoglycosides tested. Whole-genome sequencing of KP2757 demonstrated that the strain contained one chromosome and three plasmids, with all the aminoglycoside resistance genes (including two copies of armA and six AME genes) being located on a conjugative plasmid, p2757-346, belonging to type IncHI5. Comparative genomic analysis of eight IncHI5 plasmids showed that six of them carried two copies of the intact armA gene in the complete or truncated Tn1548 transposon. To the best of our knowledge, for the first time, we observed that two copies of armA together with six AME genes coexisted on the same plasmid in a strain of K. variicola with HLAR. Comparative genomic analysis of eight armA-carrying IncHI5 plasmids isolated from humans and sediment was performed, suggesting the potential for dissemination of these plasmids among bacteria from different sources. These results demonstrated the necessity of monitoring the prevalence of IncHI5 plasmids to restrict their worldwide dissemination.


Author(s):  
Behrouz Latifi ◽  
Saeed Tajbakhsh ◽  
Leila Ahadi ◽  
Forough Yousefi

Background and Objectives: Increasing the rate of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has given rise to a major healthcare issue in clinical settings over the past few years. Treatment of these strains is hardly effective since the plasmid encoding ESBL may also carry other resistance genes including aminoglycosides. The current study aimed to evaluate the prevalence of ESBL-producing K. pneumoniae and investigate the coexistence of Cefoxitamase-Munich (bla ) with aminoglycoside-modifying enzyme (AME) genes, aac(3)IIa as well as aac(6′)Ib, in CTX‑M‑producing K. pneumoniae isolated from patients in Bushehr province, Iran. Materials and Methods: A total of 212 K. pneumoniae isolates were collected and confirmed using polymerase chain re‑ action (PCR) of the malate dehydrogenase gene. Isolates were screened for production of ESBL. Phenotypic confirmatory test was performed using combined disk test. The genes encoding CTX-M groups and AME genes, aac(3)IIa and aac(6′)Ib, were investigated by PCR. Results: The ESBL phenotype was detected in 56 (26.4%) K. pneumoniae isolates. Moreover, 83.9% of ESBL-producing isolates carried the genes for CTX-M type β-lactamases, which were distributed into the two genetic groups of CTX-M-1 (97.8%)- and CTX-M-2 (2.1%)-related enzymes. Notably, among K. pneumoniae isolates containing the blaCTX‑M gene, 68.08% of isolates harbored AME genes. In addition, the coexistence of bla in 46.8% of CTX-M-producing K. pneumoniae isolates. Conclusion: This study provides evidence of a high prevalence of AME genes in CTX-M- producing K. pneumoniae iso‑ lates; therefore, in the initial empirical treatment of infections caused by ESBL-KP in regions with such antibiotic resistance patterns, aminoglycoside combination therapy should be undertaken carefully.


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