CTX-M and SHV-12 Î²-lactamases are the most common extended-spectrum enzymes in clinical isolates of<i>Escherichia coli</i>and<i>Klebsiella pneumoniae</i>collected from 3 university hospitals within Korea

Kim, Jungmin; Lim, Yu-Mi; Rheem, Insoo; Lee, Yeonhee; Lee, Je-Chul; Seol, Sung Yong; Lee, Yu-Chul; Cho, Dong-Taek

doi:10.1016/j.femsle.2005.02.029

Cited by 63 publications

(35 citation statements)

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“…Notably, there was an increase in the proportion of amikacin-resistant isolates to total isolates in 2005 (11,15), the association of armA and rmtB with ESBLs and/or pACBLs on conjugative plasmids might have contributed to the increase in the presence of armA and rmtB among K. pneumoniae strains in recent years.…”

Section: Discussionmentioning

confidence: 99%

Distribution of Conjugative-Plasmid-Mediated 16S rRNA Methylase Genes among Amikacin-Resistant Enterobacteriaceae Isolates Collected in 1995 to 1998 and 2001 to 2006 at a University Hospital in South Korea and Identification of Conjugative Plasmids Mediating Dissemination of 16S rRNA Methylase

Kang

Kim

et al. 2008

J Clin Microbiol

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The distribution of conjugative-plasmid-mediated 16S rRNA methylase genes among amikacin-resistant Enterobacteriaceae collected between 1995 and 1998 and between 2001 and 2006 at a university hospital in South Korea was examined, and conjugative plasmids carrying the 16S rRNA methylase genes were characterized by PCR-based replicon typing and by determination of their antimicrobial resistance pattern. Among the 7,127 isolates, 463 isolates showed a high level of resistance to amikacin, and 218 of the 463 isolates transferred amikacin resistance by conjugation. Among the 218 isolates, armA was detected in 153 isolates (88 Klebsiella pneumoniae, 28 Escherichia coli, 19 Enterobacter cloacae, and 6 Serratia marcescens isolates and 12 isolates of other organisms), and rmtB was detected in 51 isolates (32 K. pneumoniae isolates, 18 E. coli isolates, and 1 Citrobacter freundii isolate). The first appearance of armA was in 1997. The armA gene was carried by conjugative plasmids of replicon groups IncL/M, IncFIIAs, IncF, IncA/C, IncHI2, and Inc(unidentified) in 38, 20, 7, 9, 4, and 75 strains, respectively. The rmtB gene was carried by conjugative plasmids of groups IncA/C, IncF, and IncI1-I␥ in 43 strains, 7 strains, and 1 strain, respectively. Transconjugants that received the IncL/M plasmid carrying armA or the IncA/C plasmid carrying rmtB showed an additional resistance to cefotaxime. Transconjugants that received the IncFIIA plasmid or Inc(unidentified) plasmid carrying the armA gene showed an additional resistance to cefoxitin and a high MIC 50 (0.25 mg/liter) of ciprofloxacin. In conclusion, this study demonstrated that the dissemination of 16S rRNA methylase genes among the Enterobacteriaceae is mediated by conjugative plasmids of various incompatibility groups that confer resistance to multiple drugs, including aminoglycosides, extended-spectrum ␤-lactams, and/or quinolones.Aminoglycosides have a high affinity for the 16S rRNA of the bacterial 30S ribosome, and they block protein synthesis (14,20). Over the past few decades, there have been many studies conducted regarding the mechanisms of resistance to aminoglycosides. One of the most common mechanisms of resistance to aminoglycosides is the production of aminoglycoside-modifying enzymes, such as 1-N-aminoglycoside acetyltransferase (AAC), adenyltransferase, and phosphotransferase (14,20). Amikacin was developed to suppress a variety of aminoglycoside-modifying enzymes from their accessing target sites (12), and therefore rare, amikacin-resistant bacteria could be expected. Recently, a series of special methylases that protect microbial 16S rRNA, however, were identified in several nosocomial pathogens, and these enzymes are capable of conferring extraordinarily high levels of resistance (MIC Ͼ 512 mg/liter) to most clinically important aminoglycosides, including amikacin, isepamicin, arbekacin, kanamycin, tobramycin, and gentamicin (5)(6)(7)(8)(21)(22)(23)(24). Since the first identification of a gene encoding 16S rRNA methylase, rmtA, from a Pseudomonas aeru...

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Section: Discussionmentioning

confidence: 99%

Distribution of Conjugative-Plasmid-Mediated 16S rRNA Methylase Genes among Amikacin-Resistant Enterobacteriaceae Isolates Collected in 1995 to 1998 and 2001 to 2006 at a University Hospital in South Korea and Identification of Conjugative Plasmids Mediating Dissemination of 16S rRNA Methylase

Kang

Kim

et al. 2008

J Clin Microbiol

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“…However, the prevalence of bla SHV-12 in human isolates of members of the Enterobacteriaceae is increasing in many countries (Yan et al, 2000;Lee et al, 2003;Kim et al, 2005). Similarly, in Australia, bla SHV-2a and bla SHV-12 were found commonly to be present in hospital isolates of K. pneumoniae (Howard et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Identification of plasmid-mediated extended-spectrum and AmpC β-lactamases in Enterobacter spp. isolated from dogs

Sidjabat

Hanson

Smith-Moland

et al. 2007

Journal of Medical Microbiology

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The genetic determinants involved in reduced susceptibility to third-generation cephalosporins and aztreonam were identified in ten canine Enterobacter isolates associated with opportunistic infections in three veterinary hospitals in Brisbane, Australia. All isolates were evaluated by a combination of phenotypic (broth microdilution and disc susceptibility, modified disc diffusion and IEF) and genotypic (PFGE, plasmid analysis, Southern blot hybridization, bacterial conjugation, PCR and sequencing) methods to investigate genetic relatedness and to identify plasmid-mediated resistance genes, in particular b-lactamase genes responsible for extended-spectrum cephalosporin resistance. The ten canine isolates were genotypically diverse based on PFGE and belonged to either Enterobacter cloacae or Enterobacter hormaechei on the basis of 16S rRNA gene sequence analysis. Plasmid profiles were also diverse. Nine isolates contained a transmissible bla SHV-12 -carrying plasmid (~140 kb) that also conferred resistance to chloramphenicol, gentamicin, spectinomycin, tetracycline, trimethoprim and sulfonamides. In all plasmid-mediated extended-spectrum b-lactamase (ESBL)-producing isolates including transconjugants, bla SHV-12 was shown to reside in a~6.5 kb plasmid fragment. The remaining isolate that was not an ESBL producer possessed an AmpC b-lactamase gene (bla CMY-2 ) on ã 93 kb transmissible plasmid. This plasmid did not contain any other antimicrobial resistance genes. Additional plasmid-mediated b-lactamases identified in some isolates included bla TEM and bla . This is the first report of canine Enterobacter isolates containing transmissible plasmid-mediated bla SHV-12 and bla CMY-2 resistance genes. Therefore, Enterobacter isolated from opportunistic infections in dogs may be an important reservoir of plasmid-mediated resistance genes, which could potentially be spread to other members of the Enterobacteriaceae.

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“…Antimicrobial susceptibility testing and ESBL confirmatory testing were performed using the broth microdilution method or the disk diffusion method according to the recommendations of the Clinical and Laboratory Standards Institute. ESBL-related genes, such as TEM, SHV, CTX-M, and OXA, were amplified by PCR from clinical isolates as described in previous studies (13,14). MIC values of the antibiotics tested were determined using the broth microdilution method.…”

Section: Methodsmentioning

confidence: 99%

Epidemiology and Risk Factors of Community Onset Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains

Kang

Lee

et al. 2012

J Clin Microbiol

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Limited clinical information is available regarding community onset infections caused by extended-spectrum ␤-lactamase (ESBL)-producing Escherichia coli. A case-control study was performed to evaluate the epidemiology and risk factors of these types of infections. A case patient was defined as a person whose clinical sample yielded ESBL-producing E. coli. For each case patient, one control was randomly chosen from a group of outpatients from whom non-ESBL-producing E. coli had been isolated and for whom a clinical sample had been sent to the same laboratory for culturing during the following week. Of 108 cases of ESBL-producing E. coli, 56 (51.9%) were classified as health care associated (HCA). Univariate analysis showed male gender, HCA infection, severe underlying illness, and a prior receipt of antibiotics to be associated with ESBL-producing E. coli. In the multivariate analysis, HCA infection (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.67 to 6.06; P < 0.001) and previous use of antibiotics (OR, 4.88; 95% CI, 2.08 to 11.48; P < 0.001) were found to be significantly associated with the ESBL group. In a multivariate analysis that included each antibiotic, previous use of fluoroquinolone (OR, 7.32; 95% CI, 1.58 to 34.01; P ‫؍‬ 0.011) was significantly associated with ESBL-producing E. coli. Of 101 isolates in which ESBLs and their molecular relationships were studied, all isolates produced ESBLs from the CTX-M family (CTX-M-14, 40 isolates; CTX-M-15, 39 isolates; and other members of the CTX-M family, 22 isolates). In conclusion, this study confirms that ESBL-producing E. coli strains are a notable cause of community onset infections in predisposed patients. HCA infection and previous use of fluoroquinolone were significant factors associated with ESBL-producing E. coli in community onset infections. During the past 2 decades, antimicrobial-resistant strains that produce extended-spectrum ␤-lactamases (ESBLs) have emerged among Enterobacteriaceae, predominantly among Escherichia coli and Klebsiella pneumoniae (5,20,21). Subsequently, ESBL-producing E. coli has gained worldwide recognition as a significant group of community-acquired pathogens (3, 22). Although most patients with community onset infections caused by these organisms have urinary tract infections (UTIs), some patients present with intra-abdominal infections and concomitant bacteremia (12, 23). Nevertheless, there is still limited information about the clinical epidemiology of community onset ESBLproducing E. coli infections. Previous studies describing the clinical and microbiological epidemiology of ESBL-producing E. coli infections have focused mainly on UTIs (2, 4, 16, 22).Because ESBL-producing organisms are frequently resistant to multiple antimicrobial agents, therapeutic options for these infections are limited (18). At present, carbapenems are recommended for the treatment of serious infections caused by ESBL-producing organisms. Given the increasing incidence and pathogenic significance of ESBL-producing E. coli in community ...

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CTX-M and SHV-12 Î²-lactamases are the most common extended-spectrum enzymes in clinical isolates ofEscherichia coliandKlebsiella pneumoniaecollected from 3 university hospitals within Korea

Cited by 63 publications

References 32 publications

Distribution of Conjugative-Plasmid-Mediated 16S rRNA Methylase Genes among Amikacin-Resistant Enterobacteriaceae Isolates Collected in 1995 to 1998 and 2001 to 2006 at a University Hospital in South Korea and Identification of Conjugative Plasmids Mediating Dissemination of 16S rRNA Methylase

Distribution of Conjugative-Plasmid-Mediated 16S rRNA Methylase Genes among Amikacin-Resistant Enterobacteriaceae Isolates Collected in 1995 to 1998 and 2001 to 2006 at a University Hospital in South Korea and Identification of Conjugative Plasmids Mediating Dissemination of 16S rRNA Methylase

Identification of plasmid-mediated extended-spectrum and AmpC β-lactamases in Enterobacter spp. isolated from dogs

Epidemiology and Risk Factors of Community Onset Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains

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