Characteristics of Metallo-beta-Lactamase-Producing Pseudomonas aeruginosa in Korea / 감염과화학요법

BACKGROUND: The aim of this study was to investigate the molecular epidemiological characteristics of metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa clinical isolates in Korea. MATERIALS AND METHODS: Three hundred and twenty nine P. aeruginosa clinical isolates were collected from 23 general hospitals in Korea from March to June 2014. Species were identified by matrix-assited laser desorption/ionization-time of flight and 16S rRNA sequencing. Antimicrobial susceptibility was determined by disk diffusion methods. Further, minimum inhibitory concentrations of carbapenems were determined by Etest. Polymerase chain reaction and sequencing were performed to identify genes encoding MBLs. Multi-locus sequence typing and pulsed-field gel electrophoresis were performed to determine epidemiological characteristics of MBL-producing P. aeruginosa isolates. RESULTS: Of the 329 isolates, 229 (69.6%) were susceptible to the carbapenems tested, including imipenem and meropenem; while 100 (30.4%) were non-susceptible to more than one of the carbapenems. Genes encoding imipenemase-6 (IMP-6) and Verona imipenemase-2 (VIM-2) MBLs were identified in 21 (6.4%) isolates (n = 17 and 4, respectively). All MBL-producing isolates showed multi-drug resistant phenotype, and a majority (n = 19) of the isolates were identified as sequence type 235 (ST235). The remaining isolates (n = 2) were identified as ST309 and ST463. CONCLUSION: P. aeruginosa ST235 might play an important role in dissemination of MBL genes in Korea.

Detección del gen codificante de la metalo-ß-lactamasa VIM-2 en un integrón de clase 1 asociado con el gen blaCTX-M-2 en un aislamiento clínico de Pseudomonas aeruginosa en el Uruguay: primera comunicación

Con el fin de analizar la presencia de metalo-ß-lactamasas en nuestro medio, se incluyeron en este estudio aislamientos de Pseudomonas aeruginosa causantes de infecciones nosocomiales en un centro hospitalario del Uruguay, en el período comprendido entre abril y setiembre de 2008. En un aislamiento se detectó la presencia del gen codificante de la metalo-ß-lactamasa VIM-2 asociado a un integrón de clase 1 y del gen codificante de una ß-lactamasa de espectro extendido CTX-M-2. Esta es la primera comunicación de la presencia de los genes blaCTX-M-2 y blaVIM-2 en un mismo aislamiento de P. aeruginosa. A pesar de que las carbapenemasas ya han sido ampliamente documentadas en varias partes del mundo, esta es la primera comunicación de una metalo-ß-lactamasa adquirida con actividad carbapenemasa en bacterias patógenas encontradas en el Uruguay.

VIM-2 metallo-ß-lactamase gen detection in a class 1 integron associated to blaCTX-M-2 in a Pseudomonas aeruginosa clinical isolate in Uruguay: first communication. In order to analyze the presence of metallo-ß-lactamase in our country, we included in this study Pseudomonas aeruginosa isolates causing nosocomial infections in a hospital from Uruguay. The presence of a metallo-ß-lactamase VIM-2 in a class 1 integron and of an extended spectrum -lactamase CTX-M-2 was detected in one isolate. This is the first report of both genes, blaCTX-M-2 and blaVIM-2,in the same P. aeruginosa isolate. Although carbapenemases have been extensively documented in the world, this is the first report of an acquired metallo-ß-lactamase with carbapenemase activity in pathogenic bacteria in Uruguay.

Study on the antibiotic resistance, homology of imipenem-resistant Pseudomonas aeruginosa strains isolated from older / 中华微生物学和免疫学杂志

Objective To identify the antibiotic resistance, homology of imipenem-resistant Pseudomonas aeruginosa strains isolated from older in Zhejiang Hospital and the carbapenemases determinants of imipenem-resistant strains. MethodsTwo hundred and sixty-two strains of Pseudomonas aeruginosa were isolated through May 2006 to May 2009 from older in Zhejiang Hospitals. K-B method was used to determine the 16 antimicrobial agents resistance of these 262 strains. The MICs of strains to 14 antimicrobial agents were determined by agar dilution and E test method. The coding sequence of Metallo-β-lactamases (MBL) were amplified, PCR products were purified, cloned and sequenced. The homology of these isolates was analyzed by pulse-field gel electrophoresis(PFGE). ResultsOne hundred and four strains of imipenem-resistant Pseudomonas aeruginosa were screened from 262 strains. The resistant rates of 104 isolates of Pseudomonas aeruginosa to ampicillin/sulbactam and cefoperazone/sulbactam were 78.9％ and 35.9％ ; polymyxin E had a minimal resistance of 6.0％ ; minocycline had a resistance rate of 58.3％. The resistant rates to other antimicrobial agents were more than 70.0％. Twelve imipenem-resistant Pseudomonas aeruginosa strains contained MBL gene and two kinds of integron were detected from 10 of these 12 strains. Twelve strains of Pseudomonas aeruginosa belonged to 5 epidemic PFGE-clone. ConclusionAll of the imipenem-resistant Pseudomonas aeruginosa which had cause outbreaks in Zhejiang Hospital. MBL were not the most popular gene type. All of the MBL gene types were VIM-2. The blaVIM-2 gene cassettes located in diflerent class 1 integrons. The integrons dissemination was the most important style of strains spread.

Prevalence of Metallo-beta-lactamases in Imipenem-non-susceptible Pseudomonas aeruginosa and Acinetobacter baumannii / 대한임상미생물학회지

BACKGROUND: Metallo-beta-lactamases (MBLs) have been reported in gram negative bacilli and are becoming increasingly important clinically because the enzymes hydrolyse almost all beta-lactams, including carbapenems. Thus, the present study was conducted to determine the prevalence of MBL types in imipenem-nonsusceptible Pseudomonas aeruginosa and Acinetobacter baumannii isolated from a tertiary teaching hospital. METHODS: Imipenem-nonsusceptible strains, 128 P. aeruginosa and 93 A. baumannii, were collected from clinical specimens. Identification and susceptibility tests were determined by Vitek GNI and GNS cards. MBL production was determined by modified Hodge test and imipenem-EDTA synergy test. Multiplex PCR amplification of MBL genes including blaIMP-1, blaVIM-1 and blaVIM-2 were performed. RESULTS: Thirty-one P. aeruginosa (24.2%) isolates and 3 A. baumannii (3.2%) were found to be MBL producers. In P. aeruginosa, 20 (15.6%) and 11 (8.6%) isolates were positive for blaIMP-1 and blaVIM-2, respectively whereas 1 (1.0%) and 2 (2.2%) isolates in A. baumannii, respectively. CONCLUSION: IMP-1 is more prevalent MBL type than VIM-2 among imipenem-nonsusceptible P. aeruginosa unlike in other studies. Larger numbers of isolates and sequential studies are strongly recommended for the useful evaluation and monitoring of MBL production in the hospital setting to infection-control.

Metallo-beta-Lactamase-Producing Pseudomonas spp. in Korea: High Prevalence of Isolates with VIM-2 Type and Emergence of Isolates with IMP-1 Type

PURPOSE: Two Korean nationwide studies showed that metallo-beta-lactamases (MBLs)-producing-Pseudomonas spp. are not rare. The aim of this study was to assess the trends of MBL-producing isolates among imipenem-resistant isolates of Pseudomonas spp. MATERIALS AND METHODS: Imipenem-resistant clinical isolates were collected from 23 hospitals and one commercial laboratory participating in the KONSAR program in 2005. Polymerase chain reaction (PCR) was used to detect MBL genes. RESULTS: Alleles of MBL genes were detected in 10.8% of 415 Pseudomonas aeruginosa and 66.7% of 12 P. putida isolates from 18 of 24 hospitals/laboratory. Among the 14 IMP-1-like and 39 VIM-2-like MBLs, emergence of IMP-6 was detected for the first time. CONCLUSION: Prevalence of MBL-producing P. aeruginosa has not significantly increased, but IMP-6 emerged in P. aeruginosa.

Antimicrobial Resistance among Clinical Isolates of Pseudomonas aeruginosa from Non-tertiary Care Hospitals in Korea, 2002-2004 / 감염과화학요법

BACKGROUND: Increasing numbers of resistant and multidrug resistant (MDR) isolates of Pseudomonas aeruginosa have become a worldwide problem. This report provides the trend of antimicrobial resistance, the proportions of MDR and metallo-beta-lactamase-producing isolates among clinical isolates of P. aeruginosa in Korea. MATERIALS AND METHODS: Clinical isolates of P. aeruginosa were collected from two representative reference laboratories during 2002-2004. Clinical information regarding specimens and type of hospital for isolates was investigated. Antimicrobial susceptibility against 11 antibiotics was tested by disk diffusion according to NCCLS criteria. MDR was assessed as resistance to > or =3 of the core drugs (ceftazidime, ciprofloxacin, gentamicin, imipenem and piperacillin). PCR assays and sequencing for detection of blaVIM-2 and blaIMP-1 gene were carried out. RESULTS: Of 1,748 P. aeruginosa isolates, 179 isolates were collected from primary care hospitals and 1,569 isolates were recovered from outpatients and inpatients in secondary care hospitals. From 2002 to 2004, rates of resistance to ceftazidime and imipenem increased from 10% to 12.3% and from 14.8% to 15.9%, respectively. Rates of resistance to amikacin (from 26.2% to 31.0%) and ciprofloxacin (from 35.6% to 46.2%) increased annually. In the period 2002-2004, decreasing of susceptibility to meropenem (from 83.4% to 76.8%) was observed, but meropenem was the most potent agent against P. aeruginosa isolates studied. During the 3-year period, MDR P. aeruginosa accounted for 26.4-33.5% of clinical isolates and the most common MDR phenotype was concurrent resistance to piperacillin, gentamicin and ciprofloxacin. The prevalence of VIM-2-producing isolates obviously increased from 1.7% in 2002 to 6.3% in 2004. CONCLUSIONS: These results suggested that MDR P. aeruginosa was already prevalent in one third of clinical isolates and VIM-2-producing P. aeruginosa isolates disseminated in non-tertiary care hospitals in Korea.

Antimicrobial Resistance among Clinical Isolates of Pseudomonas aeruginosa from Non-tertiary Care Hospitals in Korea, 2002-2004 / 감염과화학요법

BACKGROUND: Increasing numbers of resistant and multidrug resistant (MDR) isolates of Pseudomonas aeruginosa have become a worldwide problem. This report provides the trend of antimicrobial resistance, the proportions of MDR and metallo-beta-lactamase-producing isolates among clinical isolates of P. aeruginosa in Korea. MATERIALS AND METHODS: Clinical isolates of P. aeruginosa were collected from two representative reference laboratories during 2002-2004. Clinical information regarding specimens and type of hospital for isolates was investigated. Antimicrobial susceptibility against 11 antibiotics was tested by disk diffusion according to NCCLS criteria. MDR was assessed as resistance to > or =3 of the core drugs (ceftazidime, ciprofloxacin, gentamicin, imipenem and piperacillin). PCR assays and sequencing for detection of blaVIM-2 and blaIMP-1 gene were carried out. RESULTS: Of 1,748 P. aeruginosa isolates, 179 isolates were collected from primary care hospitals and 1,569 isolates were recovered from outpatients and inpatients in secondary care hospitals. From 2002 to 2004, rates of resistance to ceftazidime and imipenem increased from 10% to 12.3% and from 14.8% to 15.9%, respectively. Rates of resistance to amikacin (from 26.2% to 31.0%) and ciprofloxacin (from 35.6% to 46.2%) increased annually. In the period 2002-2004, decreasing of susceptibility to meropenem (from 83.4% to 76.8%) was observed, but meropenem was the most potent agent against P. aeruginosa isolates studied. During the 3-year period, MDR P. aeruginosa accounted for 26.4-33.5% of clinical isolates and the most common MDR phenotype was concurrent resistance to piperacillin, gentamicin and ciprofloxacin. The prevalence of VIM-2-producing isolates obviously increased from 1.7% in 2002 to 6.3% in 2004. CONCLUSIONS: These results suggested that MDR P. aeruginosa was already prevalent in one third of clinical isolates and VIM-2-producing P. aeruginosa isolates disseminated in non-tertiary care hospitals in Korea.

VIM-2 Type Metallo-beta-lactamase Producing Achromobacter xylosoxidans subsp. xylosoxidans Isolated from Urine Specimens / 감염과화학요법

BACKGROUND: The dissemination of metallo-beta-lactamase (MBL) producing gram-negative bacilli is of great concern because MBL can hydrolyze carbapenem. We report herein the infection by VIM-2 type MBL producing Achromobacter xylosoxidans subsp. xylosoxidans. MATERIALS AND METHODS: For seven A. xylosoxidans subsp. xylosoxidans with reduced imipenem susceptibility, the detection for MBL was performed using EDTA double disk synergy test (EDTA- DDS) and the PCR for IMP-1, VIM-1 and VIM-2 genes. The minimal inhibitory concentration (MIC) of MBL producers were determined by microbroth dilution methods. The DNA fingerprinting analysis was performed by random amplified polymorphic DNA. RESULTS: All seven isolates were MBL producers when tested with EDTA-DDS test and these isolates were VIM-2 type confirmed by the PCR and DNA sequencing analysis. The MIC against imipenem ranged from 16 to 32 microgram/mL in these isolates. The DNA fingerprints of these isolates were identical. CONCLUSION: A. xylosoxidans subsp. xylosoxidans manifest resistance against imipenem by acquisition of VIM-2 type MBL. To our knowledge, this is the first report on the VIM-2 type MBL producing A. xylosoxidans subsp. xylosoxidans.

VIM-2 Type Metallo-beta-lactamase Producing Achromobacter xylosoxidans subsp. xylosoxidans Isolated from Urine Specimens / 감염과화학요법

BACKGROUND: The dissemination of metallo-beta-lactamase (MBL) producing gram-negative bacilli is of great concern because MBL can hydrolyze carbapenem. We report herein the infection by VIM-2 type MBL producing Achromobacter xylosoxidans subsp. xylosoxidans. MATERIALS AND METHODS: For seven A. xylosoxidans subsp. xylosoxidans with reduced imipenem susceptibility, the detection for MBL was performed using EDTA double disk synergy test (EDTA- DDS) and the PCR for IMP-1, VIM-1 and VIM-2 genes. The minimal inhibitory concentration (MIC) of MBL producers were determined by microbroth dilution methods. The DNA fingerprinting analysis was performed by random amplified polymorphic DNA. RESULTS: All seven isolates were MBL producers when tested with EDTA-DDS test and these isolates were VIM-2 type confirmed by the PCR and DNA sequencing analysis. The MIC against imipenem ranged from 16 to 32 microgram/mL in these isolates. The DNA fingerprints of these isolates were identical. CONCLUSION: A. xylosoxidans subsp. xylosoxidans manifest resistance against imipenem by acquisition of VIM-2 type MBL. To our knowledge, this is the first report on the VIM-2 type MBL producing A. xylosoxidans subsp. xylosoxidans.

Production of VIM-2 Type Metallo-beta-Lactamase in Urinary Isolates of Providencia rettgeri / 대한진단검사의학회지

BACKGROUND: VIM-2 type metallo-beta-lactamase (MBL) producing strains are presently spreading to Pseudomonas spp., Acinetobacter spp. and even to Enterobacteriaceae such as Serratia marcescens, Enterobacter cloacae and Klebsiella pneumoniae in Korea. Recently we determined the phenotype and the genotype of three MBL-producing Providencia rettgeri isolated from urinary specimen of three patients with neurosurgical ward, and analyzed the blaVIM-2 containing integron of a P. rettgeri CBU852. METHODS: EDTA-disk synergy test was used for the screening of MBL, and the PCR for blaIMP-1, blaVIM-1 and blaVIM-2 was performed. The minimal inhibitory concentration of those isolates was determined by broth microdilution method, and the genomic DNA fingerprinting analysis was performed by random amplified polymorphic DNA (RAPD). The sequence of the blaVIM-2 containing integron was determined. RESULTS: Three P. rettgeri with reduced imipenem susceptibility showed the positive EDTA-disk synergy test and blaVIM-2 was detected by PCR. Antimicrobial susceptibility test showed the resistance to all beta-lactams tested, ciprofloxacin and aminoglycoside such as gentamicin, tobramycin and amikacin, indicating multidrug resistance of those isolates. RAPD analysis showed the identical DNA fingerprint of those three isolates. The novel class 1 integron, including aacA4, blaVIM-2, orf "ii" and orf "iii", was detected in a P. rettgeri CBU852. CONCLUSIONS: In this study, the multidrug resistant P. rettgeri CBU852 had blaVIM-2 containing novel class 1 integron. The emergence of blaVIM-2 producing P. rettgeri could compromise the use of carbapenem in treatment of infections caused by MBL producing bacteria. To our knowledge, this is the first report that VIM-2 MBL gene has been detected in P. rettgeri.

Screening and Identification of Metallo-beta-Lactamase Gene in Clinical Isolates of Imipenem-Resistant Pseudomonas Aeruginosa / 대한진단검사의학회지

BACKGROUND: The therapeutic difficulty due to wide-spread emergence of multiply resistant strains is a major problem in Pseudomonas aeruginosa infection. Carbapenem-resistant P. aeruginosa strains are being isolated with increasing frequency. Clinical isolates of P. aeruginosa with transferable imipen-em resistance due to production of metallo-beta-lactamase (MBL) have been reported. This study was performed to determine the usefulness of the imipenem-EDTA disk test to detect MBL, to examine the prevalence of MBL in a tertiary care hospital in Korea. METHODS: One hundred sixteen P. aeruginosa isolates with reduced susceptibilities to imipenem were collected during the period of 2000-2003 in the Samsung Medical Center. Imipenem-resistant P. aeruginosa isolates were examined for MBL production by imipenem-EDTA disk tests. To detect of blaIMP-1 , blaVIM-1, and blaVIM-2 genes, polymerase chain reactions (PCR) were performed and the positive isolates were confirmed by sequencing. RESULTS: Among 116 clinical isolates of P. aeruginosa, 20 isolates (17.2%) were positive for the imipenem-EDTA disk tests. Nineteen isolates (16.4%) carried VIM-2. Accoroding to PCR results, the sensitivity, specificity, and test efficiency of the imipenem-EDTA disk tests were 89%, 97%, and 96%, respectively. CONCLUSIONS: The imipenem-EDTA disk test is sensitive and specific for detecting VIM producer. VIM-2 may be an important MBL in P. aeruginosa in tertiary care hospitals the Korea. The spread of MBL genes could compromise the future usefulness of carbapenem for the treatment of gram-neg-ative bacilli infections.