Genomic characteristics of a Klebsiella pneumoniae strain coproducing carbapenemases KPC-2 and NDM-5 / 中华微生物学和免疫学杂志

Objective:To analyze the characteristics of drug resistance genes in a Klebsiella pneumoniae strain coproducing carbapenemases KPC-2 and NDM-5. Methods:Klebsiella pneumoniae KPN-hnqyy was separated from the stool specimen of a patient in the Hematology Department of Affiliated Cancer Hospital of Zhengzhou University. The strain was identified with a BD Phenix-M50 automated microbiology system and the minimum inhibitory concentration against the strain was measured as well. The genotypes of the carbapenemases were tested by enzyme immunochromatographic assay and PCR method. The transferability of related plasmids was analyzed by conjugation test. Whole-genome sequencing of the strain was conducted using PacBio and Illumina platforms. The MLST type, resistance gene and plasmid type of the strain were retrieved in BacWGSTdb. The genome and open reading frame sequence of the strain were compared using Easyfig_2.2.3. Visual cycle graphs were generated using BRIG v0.95. Results:Klebsiella pneumoniae KPN-hnqyy was resistant to carbapenem antibiotics. It belonged to ST11 and carried two carbapenemase genes of blaKPC-2 and blaNDM-5. The conjugant only harbored the blaKPC-2 gene. Whole-genome sequencing revealed that the strain contained one chromosome and three plasmids. Its chromosome genome shared more than 99.9% similarity with that of Klebsiella pneumonia KP69 and KP19-2029. Moreover, a similar IncR and IncFⅠ resistance gene fusion region was contained in different types of plasmids carried by them: the blaKPC-2 gene was located in a structure—which evolved from the Tn3-△Tn4401-Tn1721/Tn1722 sequence—inside this fusion region with its ends inserted into the transposase IS26 gene; the blaNDM-5 gene was located on a transposon containing the special plasmids of the insertion fragment in phages, with its ends inserted into the transposase IS26 gene too. Conclusions:The IncR and IncFⅡ resistance gene fusion region of blaKPC-2 carried by Klebsiella pneumoniae ST11 might be widely coexistent with the chromosomal genome. The blaNDM-5 gene carried by special plasmids might be accidentally obtained through gene recombination mediated by transposable element IS26. The wide transmission of Klebsiella pneumoniae ST11 carrying the blaKPC-2 gene in China and its ability to obtain other carbapenemase genes through transposable element IS26 were well worth attention.

MDR Escherichia coli carrying CTX-M-24 (IncF[F-:A1:B32]) and KPC-2 (IncX3/IncU) plasmids isolated from community-acquired urinary trainfection in Brazil

ABSTRACT Acquired antibiotic resistance in bacteria has become an important worldwide challenge. Currently, several bacteria, including Escherichia coli, have multidrug resistance profiles. Genes such as bla CTX-M-24 and bla KPC-2 (carbapenemase) are widespread. This research letter reports about a genomic surveillance study where multidrug-resistant E. coli containing CTX-M-24(IncF [F-:A1:B32]) and KPC-2(IncX3/IncU) plasmids were obtained from community- acquired urinary tract infection in Brazil.

In vitro antibacterial effects of imipenem combined with conventional antibiotics on bla KPC-2 type carbapenem resistant klebsiella pneumoniae / 中国基层医药

Objective:To investigate the in vitro antibacterial effects of imipenem combined with common antibiotics on bla KPC-2 type carbapenem resistant klebsiella pneumoniae (CRKP) targeting bla KPC-2 gene. Methods:Six strains of unrepeated bla KPC-2 type confirmed by polymerase chain reaction and DNA sequence were isolated in Yueqing People's Hospital, China between January 2018 and January 2019 were included in this study. The susceptibility rate of imipenem against nine conventionally used antibiotics was determined. The sensitivity test of imipenem combined with eight antibiotics was performed with the checkerboard method. Fractional inhibitory concentration was calculated to assess the efficacy of imipenem combined with common antibiotics. The in vitro treatment time-antibacterial effect curve was drawn to evaluate the antibacterial effects. Results:The resistance rate of six strains of bla KPC-2 type was 100.00% (6/6) for imipenem, meropenem, ceftazidime, ciprofloxacin, rifampicin and cefotaxime, and it was 66.67% (4/6) for minocycline and clavulanic acid and 33.33% (2/6) for tigecycline. Imipenem combined with tigecycline had a better antibacterial effect and exhibited a synergistic effect on four strains of bla KPC-2 type CRKP and an additive effect on two strains of Bla KPC-2 type CRKP. The curve of time for in vitro treatment of KPN2 with imipenem combined with tigecycline against bactericidal effect revealed that the antibacterial rate of imipenem at the 1/2 minimum inhibitory concentration combined with tigecycline at the 1/4 minimum inhibitory concentration was > 95% at (t+2) and the antibacterial effect could maintain (t+10) hours to (t+12) hours. The antibacterial rate of imipenem combined with tigecycline against strain 002 was gradually decreased with time, and the growth curve of strain 002 rised gradually. Conclusion:In vitro drug sensitivity test revealed that imipenem combined with tigecycline exhibits a good synergistic effect on bla KPC-2 type CRKP. Findings from this study provide a reference for clinical treatment of bla KPC-2 type CRKP.

Identification of plasmid IncQ1 and NTEKPC-IId harboring bla KPC-2 in isolates from Klebsiella pneumoniae infections in patients from Recife-PE, Brazil

Abstract INTRODUCTION: This study investigated the genetic environment of bla KPC-2 in Klebsiella pnemoniae multi-drug resistant clinical isolates. METHODS: Four carbapenemase gene isolates resistant to carbapenems, collected from infected patients from two hospitals in Brazil, were investigated using polymerase chain reaction and plasmid DNA sequencing. RESULTS: The bla KPC-2 gene was located between ISKpn6 and a resolvase tnpR in the non-Tn4401 element (NTEKPC-IId). It was detected on a plasmid belonging to the IncQ1 group. CONCLUSIONS To our knowledge, this is the first report of the presence of the bla KPC-2 gene in the NTEKPC-IId element carried by plasmid IncQ1 from infections in Brazil.

Capsular polysaccharide serotyping and carbapenem resistance mechanism of hypermucoviscous Klebsiella pneumoniae / 中国感染与化疗杂志

Objective To investigate the capsular polysaccharide (CPS) serotypes and molecular characteristics of carbapenem resistant hypermucoviscous Klebsiella pneumoniae (CR-HMKP) and study the possible mechanism of carbapenem resistance. Methods A retrospective study was conducted on 18 nonduplicate CR-HMKP strains which were collected from the First Affiliated Hospital of Nanchang University from 2012 to 2016. The clinical data were retrieved from medical records. The capsular serotypes, resistance genes and virulence factors were detected by polymerase chain reaction and DNA sequencing. Antimicrobial susceptibility testing was determined on VITEK 2 compact system. The CR-HMKP strains were characterized molecularly by using PCR, multilocus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE). Modified carbapenem inactivation method was used to screen carbapenemase-producing strains. Plasmid conjugation transfer experiments were carried out to study transmission of carbapenem resistance. Results Eighteen (2.7％) CR-HMKP isolates were identified, which belonged to 4 serotypes, including wzi128-K1 (n=1), wzi206-K57 (n=1), wzi2-K2 (n=2), and wzi64-K14.64 (n=14). PCR and sequencing analysis identified blaNDM-1 gene in 2 CR-HMKP strains, blaKPC-2 gene in 17 strains, qnrS1 gene in 18 strains, blaCTX-M-3 gene in 3 strains, blaCTX-M-14 gene in 18 strains, blaTEM-1 gene in 16 strains, blaSHV-12 gene in 17 strains, and rmtB in 5 strains. All the 18 CR-HMKP strains carried virulence-associated genes, including rmpA (88.9％, 16/18), magA (5.6％, 1/18), iroN (83.3％, 15/18), aerobactin (27.8％, 5/18), rmpA2 (66.7％, 12/18) and mrkD (100％, 18/18). Three sequence types (STs) were identified by MLST, including ST11 (15 strains), ST86 (2 strains), and ST412 (1 strain). PFGE resulted in three major PFGE clusters, of which cluster A corresponds to ST1 isolates, and cluster B corresponds to ST86 isolates, and cluster C corresponds to ST412 isolates. All the blaKPC-2- positive strains belonged to ST11. Plasmid conjugation was successful in 5 (27.8％) of the 18 CR-HMKP isolates. Conclusions wzi64-K14.64 is the predominant capsule serotype of the CR-HMKP strains in this hospital. KPC-2 gene conjugationmay contribute to the emergence of CR-HMKP isolates. In addition, CRHMKP strain may be the highly prevalent ST11, and highly virulent CPS serotypes harboring K1/K2.

Analysis on resistance genes and homology of carbapenem-resistant Klebsiella pneumoniae / 临床检验杂志

Objective To understand the prevalence of resistance gene and homology of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from ICU of emergency.Methods A total of 19 CRKP isolates were obtained from emergency ICU of the Affiliated Hospital of Xuzhou Medical University from July 2015 to August 2016.PCR was performed to screen the genes encoding carbapenemase,extended spectrum beta-lactamase (ESBL) and AmpC.Pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were used for molecular typing of these bacterial strains.Results Among the 19 CRKP,carbapenemase-resistant genes were detectable in 18 CRKP isolates,including 17 isolates of harboring blaKPC gene and 1 strain of harboring blaNDM gene.All the 18 strains carried ESBLs genes which were identified as 8 blaSHV-12,3 blaSHV-11,5 blaSHV-2a,15 blaTEM-1,10 blaCTX-M-65,3 blaCTX-M-15,1 blaCTX-M-14 and 1 blaCTX-M-27.The 13 strains harboring cephalosporin-resistant genes were all identified as blaDHA-1.PFGE results revealed that the 19 CRKP strains were grouped into 4 types (A,B,C and D) and 4 subtypes(A1,2,3 and 4):A1 (n =12),A2(n =1),A3 (n=1),A4(n=1),B(n=2),C(n=1) and D(n=1).MLST showed that ST11 was the predominant sequence type (n=15) among the 19 CRKP strains,and ST48 (n =2),ST37 (n =1) and untyped (n =1) were also identified.The 15 blaKPC-2-producing CRKP ST11 clone shared the A type of PFGE pattern.Conclusion The report on CRKP suggested the dissemination of blaKPC-2-producing ST11 clone was existed in the ICU of emergency department in this hospital.The surveillance for drug-resistance and effective disinfectant quarantine measures should be strengthened.

Characterisation of plasmid-mediated rmtB-1 in Enterobacteriaceae clinical isolates from São Paulo, Brazil

OBJECTIVES The emergence of 16S rRNA methyltranferases (16 RMTAses) has jeopardised the clinical use of aminoglycosides. RmtB is one of the most frequently reported in Gram-negatives worldwide. In this study, we aimed to estimate the frequency of 16S RMTAses encoding genes in Enterobacteriaceae isolated in a three-month period from a tertiary Brazilian hospital. METHODS All Gram-negatives classified as resistant to amikacin, gentamicin, and tobramycin by agar screening were selected for analysis. The presence of 16SRMTases encoding genes was verified by polymerase chain reaction (PCR). Antimicrobial susceptible profile was determined by broth microdilution. The genetic relationship among these isolates was accessed by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Selected RmtB-producing isolates were characterised by whole genome sequencing (WGS) analysis. RESULTS Twenty-two of 1,052 (2.1%) Enterobacteriaceae were detected as producers of RmtB-1 [Klebsiella pneumoniae (n = 21) and Proteus mirabilis (n = 1)]. blaKPC-2 was identified among 20 RmtB-1-producing K. pneumoniae isolates that exhibited an identical PFGE and MLST (ST258) patterns. Two K. pneumoniae isolates, the A64216 (not harboring bla KPC-2), A64477 (harboring bla KPC-2) and one P. mirabilis isolate (A64421) were selected for WGS. rmtB-1 and bla KPC-2 genes were carried by distinct plasmids. While a plasmid belonging to the IncFIIk group harbored rmtB-1 in K. pneumoniae, this gene was carried by a non-typable plasmid in P. mirabilis. In the three analysed plasmids, rmtB-1 was inserted on a transposon, downstream a Tn2. CONCLUSION Our findings suggested that the rmtB-1 was harbored by plasmids distinct from those previously reported in Bolivia and China. It suggests that multiple mobilization events might have occurred in South America.

Detection of a strain of Enterobacter cloacae co-carrying NDM-1 and KPC-2 genes and its drug resistance / 中华临床感染病杂志

Objective To identify the drug resistance-related genes in a clinically isolated strain of Enterobacter cloacae.Methods A strain of Enterobacter cloacae was isolated from sputum of a patient with chronic obstructive pulmonary disease from the Affiliated Hospital of Xuzhou Medical University in March 2013.Modified Hodge test and metal enzyme inhibition test were performed for drug-resistant phenotype screening.Carbapenemase genes blaMUS-1, blaVIM-1, blaVIM-2, blaIMP, blaKPC-2, blaNDM-1, blaOXA-48 and blaGESwere amplified by polymerase chain reaction (PCR), and the positive products were sequenced and analyzed.Plasmid conjugation and transformation experiments were used to confirm that the resistance gene mediated by plasmids.Agar dilution method was used for antibiotic susceptibility test.Results Both modified Hodge test and metal enzyme inhibition test were positive in this strain of Enterobacter cloacae.blaNDM-1 gene and blaKPC-2 gene were detected by PCR, and further confirmed by sequencing.blaNDM-1 gene was carried by IncX plasmid with 54×103 bp, KPC-2 gene was carried by untyping plasmid with 42×103 bp.The strain was only sensitive to tetracycline (MIC=2 μg/mL) and tigecycline (MIC=1 μg/mL).The symptoms were improved after the patient was treated by tigecycline combined with Piperacillin/Tazobactam.Conclusion blaNDM-1 and blaKPC-2 genes in Enterobacter cloacae can be mediated by plasmids, and appropriate therapy for its infection should be based on the result of antibiotic susceptibility test.

Caracterização fenotípica e genotípica de Acinetobacter spp. e Pseudomonas aeruginosa produtores de carbapenemases / Phenotypic and genotypic characterization of carbapenemase-producing Acinetobacter spp. e Pseudomonas aeruginosa

A resistência bacteriana a antibióticos é um grave e crescente problema de saúde pública de âmbito mundial. O principal, e mais eficiente, mecanismo de resistência aos ß-lactâmicos em bacilos Gram-negativos é a produção de ß-lactamases, que possuem a capacidade de hidrolisar o anel ß-lactâmicos e consequentemente inativar essa classe de antibióticos. Vale ressaltar, que atualmente os antibióticos ß-lactâmicos são os mais utilizados clinicamente, particularmente em infecções graves. Dentre as ß-lactamases existentes destacam-se as carbapenemases, enzimas capazes de inativar a maioria dos antibióticos ß-lactâmicos. Uma grande preocupação é o fato dessas enzimas, em sua maioria, serem codificadas por plasmídeos, o que propicia a disseminação desses genes de resistência; portanto, é de extrema importância a realização de um rápido e efetivo monitoramento da presença de patógenos portadores desses genes de resistência, para que assim se possa prevenir a disseminação desses determinantes. Foram incluídos neste estudo 230 amostras únicas de Acinetobacter e Pseudomonas aeruginosa resistentes a imipenem detectados em pacientes internados em hospitais privados da cidade de São Paulo durante o período de fevereiro a outubro de 2013. As amostras foram avaliadas quanto à hidrólise de imipenem por espectrofotometria, quanto à presença de genes de carbapenemases por PCR e sequenciamento, e quanto à clonalidade por eletroforese em campos pulsados (PFGE) ou ERIC-PCR. Foram realizados ensaios de conjugação, transformação e sequenciamento completo de plasmídeos. Dentre as amostras de Acinetobacter spp. 80% (88) foram capazes de hidrolisar o imipenem. Dentre esses 76,1% (67) foram positivos para blaOXA-51-like, 19,3% (17) foram positivos para blaOXA-72. blaOXA-23, blaOXA-482 e blaIMP-1 foram detectados isoladamente em isolados distintos. O gene blaIMP-1 foi detectado em A. ursingii inserido em integron de classe 1 e representa a primeira descrição no Brasil. Uma nova carbapenemase OXA-482-like foi detectada em A. baumanii. Utilizando-se ERIC-PCR, observou-se uma grande diversidade de grupos clonais, com o máximo de quatro isolados por grupo. Dentre as amostras de P. aeruginosa, apenas 35,3% foram capazes de hidrolisar o imipenem. Dessas amostras, 14 possuíam o gene blaSPM-1, e isolados únicos possuíam, individualmente, os genes blaIMP, blaVIM, blaKPC-2 ou blaGES-23. O gene blaKPC-2 foi detectado inserido em contexto genético diferente dos descritos anteriormente, em plasmídeo IncU de 32 Kb, mobilizável, mas não conjugativo. Esta é a primeira descrição da sequencia completa de plasmídeo albergando o gene blaKPC-2 em P. aeruginosa no Brasil. Nas demais amostras (20) com atividade hidrolítica, não foram detectados genes de carbapenemase conhecidos, o que sugere a presença de genes de carbapenemase ainda não descritos. Em três amostras foi possível obter transformantes com plasmídeos, resistentes a carbapenêmicos. As amostras com blaSPM-1 apresentaram perfis de PFGE estreitamente relacionados. Em contraste, os perfis de PFGE das amostras com potenciais novas carbapenemases apresentaram índice de similaridade de Dice inferior ix a 80%, evidenciando grande diversidade clonal. Nossos achados evidenciam que a carbapenemase não intrínseca predominante em Acinetobacterem hospitais privados da cidade de São Paulo é OXA-72, e em hospitais privados há uma grande diversidade clonal. Em P. aeruginosa, a carbapenemase predominante é SPM-1, cuja disseminação é mediada por um único clone. Há potencialmente um número significativo de novas carbapenemases em Acinetobacter e P. aeruginosa, algumas delas mediadas por plasmídeos

Bacterial resistance to antibiotics is a serious and growing public health problem worldwide. The main and most efficient mechanism of resistance to ß-lactams in Gram-negative bacilli is the production of ß-lactamases, which have the ability to hydrolyze the ß-lactam ring and consequently inactivate this class of antibiotics. It is worth mentioning that currently ß-lactam antibiotics are the most used clinically, particularly in severe infections. Among the existing ß-lactamases, carbapenemases are capable of inactivating most ß-lactam antibiotics. A major concern is that these enzymes are mostly encoded by plasmids, which facilitates the spread of these resistance genes; therefore, it is of extreme importance to carry out a rapid and effective monitoring of the presence of pathogens bearing these resistance genes, in order to prevent the dissemination of these determinants. This study included 230 unique samples of imipenem-resistant Acinetobacterand Pseudomonas aeruginosa detected in patients hospitalized in private hospitals in the city of São Paulo during the period from February to October 2013. The samples were evaluated for the imipenem hydrolysis by spectrophotometry, the presence of carbapenemase genes by PCR and sequencing, and concerning clonality by pulsed field electrophoresis (PFGE) or ERIC-PCR. Conjugation, transformation and complete sequencing of plasmids were performed. Among Acinetobacter spp. samples, 80% (88) were able to hydrolyze imipenem. Among these, 76.1% (67) were positive for blaOXA-51-like genes and 19.3% (17) were positive for blaOXA-72. The blaOXA-23, blaOXA-482 and blaIMP-1 genes were detected alone in distinct isolates. The blaIMP-1 gene was detected in A. ursingii inserted in class 1 integron and represents the first description in Brazil. A novel OXA-482-like carbapenemase was detected in A. baumanii. Using ERIC-PCR, a great diversity of clonal groups was observed, with a maximum of four isolates per group. Among P. aeruginosa samples, only 35.3% were able to hydrolyze imipenem. Of these samples, 14 had the blaSPM-1 gene, and single isolates individually possessed the blaIMP, blaVIM, blaKPC-2 or blaGES-23 genes. The blaKPC-2 gene was found inserted in a genetic context different from those described previously, in a mobilizable, but not conjugative, 32 Kb IncU plasmid. This is the first description of the complete nucleotide sequence of a plasmid harboring the blaKPC-2 gene in P. aeruginosa in Brazil. In the remaining samples (20) with hydrolytic activity, no known carbapenemase genes were detected, suggesting the presence of carbapenemase genes not yet described. In three samples it was possible to obtain transformants with plasmids, resistant to carbapenems. Samples with blaSPM-1 showed closely related PFGE profiles. In contrast, the PFGE profiles of the samples with potential new carbapenemases showed Dice similarity index lower than 80%, evidencing a great clonal diversity. Our findings show that the predominant non-intrinsic carbapenemase in Acinetobacter in the city of São Paulo is OXA-72, and in private hospitals there is great clonal diversity. In P. aeruginosa, the predominant carbapenemase is SPM-1, the spread of this enzyme is mediated by a single clone. There are potentially a significant number of new carbapenemases in Acinetobacter and P. aeruginosa, some of them plasmid mediated

Factores relacionados con el control exitoso de un brote por Klebsiella pneumoniae productora de KPC-2 en una unidad de cuidado intensivo en Bogotá, Colombia / Factors related to successful control of an outbreak by Klebsiella pneumonia -producing KPC-2 in an intensive care unit in Bogotá, Colombia

La resistencia a carbapenémicos en Klebsiella pneumoniae ha aumentado de manera considerable, incrementando las tasas de morbimortalidad. El objetivo de este trabajo fue describir las características epidemiológicas, microbiológicas y las medidas de intervención que permitieron el control exitoso de un brote de Klebsiella pneumoniae productora de KPC-2. Métodos: El estudio se realizó en 2 periodos: el primero durante el brote, con instauración de un protocolo de medidas de intervención; y el segundo, de seguimiento posbrote. Se realizaron pruebas de identificación y susceptibilidad por sistema automatizado, tamización de carbapenemasas por test de Hodge modificado, PCR para detección de los genes bla KPC, bla KPC-2, NDM-1 y estudio de clonalidad por electroforesis de campos pulsados. Resultados: Durante el brote, se identificaron 18 aislamientos de Klebsiella pneumoniae productora de KPC en 11 pacientes. Tres casos fueron confirmados como infección intrahospitalaria. La técnica de PCR reveló la presencia del gen bla KPC en 21 de 22 aislamientos (pacientes y medio ambiente) y se identificó la presencia de un clon con una similitud superior al 75%. En el periodo posbrote los cultivos ambientales y de búsqueda de colonizados fueron negativos. Discusión: Se evidenció un control exitoso del brote producido por un clon. La implementación de un protocolo de intervención y la monitorización de su cumplimiento, la comunicación efectiva y el trabajo en equipo fueron indispensables para evitar su propagación y evitar un comportamiento endémico posbrote.

The considerable increase in carbapenem-resistant Klebsiella pneumoniae has caused an increase in mortality and morbidity rates. The aim of this study was to describe its epidemiological and microbiological characteristics and the intervention measures that controlled an outbreak caused by K. pneumoniae- producing KPC-2 B-lactamase. Methods: The study was divided into 2 periods: the first during the outbreak with the implementation of a bundle and the second a post-outbreak surveillance. We performed tests for identification and susceptibility by using an automated system, screening carbapenemases by the Modified-Hodge test, bla KPC, bla KPC-2 and NDM-1 identification by PCR and clonal relationship characterisation by PFGE. Results: During the outbreak, there were 18 isolates of Klebsiella pneumoniae -producing KPC- 2 in 11 patients. Three cases were confirmed as hospital-acquired infection. Of 22 isolates, 21 were positive to bla KPC by PCR (samples from patients and environment) and a clone was identified with a similarity of greater than 75%. During the post-outbreak surveillance, we did not find any new positive cultures from surfaces and there were no new colonisations. Discussion: This was a successful control of an outbreak produced by a clone. The implementation of a bundle and a subsequent surveillance to monitor its fulfilment, effective communication and teamwork were crucial to inhibit propagation of the infection and to prevent an endemic behaviour post-outbreak.

Prevalence and Molecular Characteristics of Carbapenemase-Producing Enterobacteriaceae From Five Hospitals in Korea

BACKGROUND: The emergence of carbapenemase-producing Enterobacteriaceae (CPE) represents a major clinical problem because these bacteria are resistant to most antibiotics. CPE remain relatively uncommon in Korea. We report the prevalence, clinical characteristics, and molecular epidemiology of CPE isolates collected from five university hospitals in Korea. METHODS: Between January and December 2015, 393 non-duplicated isolates that were nonsusceptible to ertapenem were analyzed. Production of carbapenemase, extended-spectrum β-lactamase, and AmpC β-lactamase was determined by genotypic tests. Antimicrobial susceptibility profiles were determined by using an Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC)-2-producing and oxacillinase (OXA)-232-producing Klebsiella pneumoniae isolates was determined by pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 393 isolates tested, 79 (20.1%) were CPE. Of these 79 isolates, 47 (59.5%) harbored the bla(OXA-232) gene while the remaining isolates carried genes bla(KPC-2) (n=27), bla(IMP-1) (n=4), and bla(NDM-1) (n=1). Among the 24 KPC-2 K. pneumoniae isolates from hospital B, 100% were resistant to carbapenems, 8% to colistin, and 0% to tigecycline. Among the 45 OXA-232 K. pneumoniae at hospital C, 95% were resistant to ertapenem, 68% to imipenem, 95% to meropenem, 10% to colistin, and 24% to tigecycline. PFGE analysis revealed a unique pattern for KPC-2 K. pneumoniae and identified 30 isolates belonging to the dominant pulsotypes (PT)1 and PT2 among 41 OXA-232 K. pneumoniae isolates. CONCLUSIONS: CPE strains are present in Korea, with the majority of K. pneumoniae isolates producing OXA-232 and KPC-2. The prevalence and predominant genotypes of CPE show hospital-specific differences.

Carbapenemases KPC-2 and IMP-4 mediated carbapenem resistance in Enterobacteriaceae strains / 中华微生物学和免疫学杂志

Objective To investigate the mechanism of carbapenem-resistant in Enterobacteriaceae strains isolated from Fuyang First People′s Hospital and to analyze their epidemiological features. Methods The Enterobacteriaceae strains with reduced ertapenem susceptibility were isolated from the Fuy-ang First People′s Hospital during January 2013 to August 2014.K-B disk diffusion and E-test were per-formed to detect the antimicrobial susceptibilities of those strains.The modified Hodge test, ethylenediami-netetraacetic acid ( EDTA) disk synergy test and extended-spectrumβ-lactamases ( ESBLs) confirmation test were used to screen out the carbapenem-resistant phenotypes.PCR analysis and gene sequencing were used to analyze drug resistance genes, genetic structures surrounding the blaKPC-2 gene and seven house-keeping genes of Klebsiella pneumonia ( K.pneumoniae) strains.The sequences of the seven house-keeping genes were analyzed with multilocus sequence typing ( MLST) .Pulsed field gel electrophoresis ( PFGE) was per-formed for homology analysis within the same species.S1-PFGE in combination with Southern blot analysis was used to determine the location of carbapenem resistance genes.Results A total of 19 Enterobacteriace-ae isolates with reduced susceptibility to ertapenem were screened out.Each of them was resistant to multiple antibiotics and harbored several resistance genes.Seven genes including the blaKPC-2 , blaIMP-4 , blaSHV-1 , blaCTX-M-65 , blaCTX-M-15 , blaTEM-1 and rmtB genes were the prevalent drug resistance genes.Fourteen out of the nineteen strains were identified as K.pneumoniae strains, mainly belonged to the ST11 type according to the results of MLST.Among the nineteen strains, eleven K.pneumoniae isolates and one Escherichia coli isolate carried the blaKPC-2 gene, located on plasmids varying in size (95 kb, 140 kb, 200 kb and 240 kb) .The ge-netic structures of all isolates were ISKpn8, blaKPC-2 and ISKpn6-like from upstream to downstream.The blaIMP-4 gene was detected in one Klebsiella oxytoca isolate and one K.pneumoniae isolate, located on a plas-mid about 300 kb in size.Conclusion Carbapenemases KPC-2 and IMP-4 were closely related to the car-bapenem resistance in carbapenem-resistant Enterobacteriaceae strains isolated form the Fuyang First People′s Hospital.No predominant clone was found in those carbapenem-resistant K.pneumoniae isolates.

Molecular types of carbapenem-non-susceptible Escherichia coli isolates and their mechanism of drug resistance / 中华微生物学和免疫学杂志

Objective To investigate the molecular types of carbapenem-non-susceptible Esche-richia coli ( E.coli) isolates and their mechanism of carbapenem resistance .Methods Twenty-two carbap-enem-non-susceptible E.coli strains were isolated from 3 hospitals in Hangzhou from 2007 to 2011.The mini-mum inhibitory concentrations ( MICs) of antimicrobials to those isolates were determined by agar dilution method and E-test.The molecular mechanisms of carbapenem resistance of E.coli isolates were analyzed by conjugation experiment,PCR and DNA sequencing.Pulsed-field gel electrophoresis (PFGE),multilocus se-quence typing ( MLST ) , and phylogenetic typing were performed to analyze the molecular epidemiology of those isolates.Results The MICs of imipenem and meropenem to 22 E.coli isolates were ranged from 1 μg/ml to 16 μg/ml,and the MICs of ertapenem were 2 μg/ml to 64 μg/ml.All E.coli isolates produced the KPC-2 carbapenemase and various β-lactamases , and some of them also produced plasmid-mediated AmpC enzymes.Carbapenem resistance was transferred by conjugation and transformation from 22 E.coli iso-lates to E.coli EC600 strains.The E.coli transconjugants or transformants acquired the blaKPC-2 gene and showed similar antibiotic susceptibility patterns in comparison with donor strains .Only a few isolates were in-distinguishable or closely related as indicated by PFGE .Four sequence types including ST131 (9 isolates), ST648 (5 isolates),ST38 (2 isolates) and ST405 (2 isolates) were identified by MLST.Phylogenetic analy-sis indicated that 9 ST131 isolates belonged to phylogenetic group B 2 and the other isolates belonged to group D (11 isolates),group B1 (1 isolate) and group A (1 isolate),respectively.Conclusion The sequence type of prevalent E.coli isolates producing KPC-2 from Hangzhou was ST131,which is an international epi-demic,multidrug-resistant clone,followed by ST648.

A strain of extensively drug resistant and KPC-2 carbapenemase-producing Kleb-siella pneumoniae is identified in Dongguan,Guangdong province / 中国感染与化疗杂志

Objective To explore the extensively drug resistant mechanism and clinical treatment strategy of Klebsiella pneu-moniae .Methods The isolate was identified by Vitek2 Compact System.Antimicrobial susceptibility testing was conducted by Kirby-Bauer method.KPC-2 carbapenemase was detected by modified Hodge test.The gene encoding KPC-2 carbapenemase was amplified by polymerase chain reaction (PCR)and then sequenced.Results The strain was resistant to all antibiotics used in routine antimicrobial susceptibility testing except amikacin.Modified Hodge test showed positive result.KPC-2 gene was detected by PCR.The sequence was consistent with that of 11844849 in GenBank.After treatment for one month,no exten-sively drug resistant K.pneumoniae strain was detected from the patient.Conclusions It is necessary to strengthen the monito-ring and improve the awareness of extensively drug resistant K.pneumoniae for better control of such infections.

Isolation of a Klebsiella pneumoniae Isolate of Sequence Type 258 Producing KPC-2 Carbapenemase in Korea / 대한진단검사의학회지

Carbapenem-resistant Klebsiella pneumoniae isolates producing K. pneumoniae carbapenemases (KPC) were first reported in the USA in 2001, and since then, this infection has been reported in Europe, Israel, South America, and China. In Korea, the first KPC-2-producing K. pneumoniae sequence type (ST) 11 strain was detected in 2010. We report the case of a patient with a urinary tract infection caused by KPC-2-producing K. pneumoniae. This is the second report of a KPC-2-producing K. pneumoniae infection in Korea, but the multilocus sequence type was ST258. The KPC-2-producing isolate was resistant to all tested beta-lactams (including imipenem and meropenem), amikacin, tobramycin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole, but was susceptible to gentamicin, colistin, polymyxin B, and tigecycline. The KPC-2-producing isolate was negative to phenotypic extended-spectrum beta-lactamase (ESBL) and AmpC detection tests and positive to modified Hodge test and carbapenemase inhibition test with aminophenylboronic acid.