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BACKGROUND@#The existing modified carbapenem inactivation methods (mCIMs) recommended by the CLSI for detecting carbapenemase production have not been applicable for Acinetobacter baumannii. We evaluated the influence of matrices used in mCIMs and CIMTris on the stability of the disks for detecting carbapenemase producers and suggested optimal mCIM conditions for detecting carbapenemase-producing A. baumannii.@*METHODS@#Seventy-three A. baumannii isolates characterized for antimicrobial susceptibility and carbapenemase encoding genes were tested for carbapenemase production using mCIM and CIMTris. The influence of the matrices (Tryptic soy broth [TSB] and Tris-HCl) used in these methods on the stability of the meropenem (MEM) disk was also evaluated. The mCIM conditions were adjusted to enhance screening sensitivity and specificity for detecting carbapenemase-producing A. baumannii.@*RESULTS@#The matrices had an impact on the stability of the MEM disk after the incubation period (two or four hrs). TSB nutrient broth is an appropriate matrix for mCIM compared with Tris-HCl pH 7.6, which leads to the loss of MEM activity in CIMTris. The sensitivity and the specificity of the optimal mCIM were both 100%.@*CONCLUSIONS@#We established optimal mCIM conditions for simple, accurate, and reproducible detection of carbapenemase-producing A. baumannii.
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BACKGROUND: Rapid detection of carbapenemase-producing gram-negative bacilli (GNB) is required for optimal treatment of infected patients. We developed and assessed a new disk carbapenemase test (DCT). METHODS: Paper disks containing 0.3 mg of imipenem and bromothymol blue indicator were developed, and the performance of the DCT were evaluated by using 742 strains of GNB with or without carbapenemases. RESULTS: The paper disks were simple to prepare, and the dried disks were stable at -20℃ and at 4℃. The DCT detected 212 of 215 strains (98.6% sensitivity with 95% confidence interval [CI] 96.0-99.5%) of GNB with known class A (KPC and Sme) and class B (NDM, IMP, VIM, and SIM) carbapenemases within 60 min, but failed to detect GES-5 carbapenemase. The DCT also detected all two Escherichia coli isolates with OXA-48, but failed to detect GNB with OXA-232, and other OXA carbapenemases. The DCT showed 100% specificity (95% CI, 99.2-100%) in the test of 448 imipenem-nonsusceptible, but carbapenemase genes not tested, clinical isolates of GNB. CONCLUSIONS: The DCT is simple and can be easily performed, even in small laboratories, for the rapid detection of GNB with KPC, NDM and the majority of IMP, VIM, and SIM carbapenemases.
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Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Azul de Bromotimol/química , Farmacorresistência Bacteriana , Bactérias Gram-Negativas/efeitos dos fármacos , Imipenem/farmacologia , Testes de Sensibilidade Microbiana/métodos , Papel , beta-Lactamases/metabolismoRESUMO
PURPOSE: The detection of high-level tetracycline-resistant strains of Neisseria gonorrhoeae (TRNG) can make important epidemiological contributions that are relevant to controlling infections from this pathogen. In this study, we aimed to determine the incidence of TRNG isolates over time and also to investigate the characteristics and genetic epidemiology of these TRNG isolates in Korea. MATERIALS AND METHODS: The antimicrobial susceptibilities of 601 isolates of N. gonorrhoeae from 2004 to 2011 were tested by standard Clinical and Laboratory Standards Institute methods. To determine the molecular epidemiological relatedness, N. gonorrhoeae multi-antigen sequence typing was performed. RESULTS: The incidence of TRNG increased from 2% in 2004 to 21% in 2011. The minimum inhibitory concentration distributions of ceftriaxone and susceptibility of ciprofloxacin in TRNG were different from non-TRNG and varied according to the year of isolation. Most of the TRNG isolates collected from 2004 to 2007 exhibited genetic relatedness, with sequence type (ST) 1798 being the most common. From 2008 to 2011, the STs of the isolates became more variable and introduction of genetically unrelated TRNG were noted. CONCLUSION: The increased incidence of TRNG strains until 2007 appears to be due, at least in part, to clonal spread. However, we propose that the emergence of various STs since 2008 could be associated with foreign import.
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Humanos , Antibacterianos/farmacologia , Ceftriaxona/farmacologia , Ciprofloxacina/farmacologia , DNA Bacteriano/análise , Farmacorresistência Bacteriana Múltipla/genética , Gonorreia/tratamento farmacológico , Incidência , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Neisseria gonorrhoeae/efeitos dos fármacos , República da Coreia/epidemiologia , Análise de Sequência de DNA , Tetraciclina/farmacologia , Tetraciclinas/farmacologiaRESUMO
We report three cases of recently named Bacteroides spp. isolates, two B. faecis isolates and one B. intestinalis isolate from clinical specimens of inpatients at a Korean tertiary-care hospital in 2011. All isolates were susceptible to piperacillin-tazobactam, imipenem, meropenem, chloramphenicol, and metronidazole.
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Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Antibacterianos/farmacologia , Bacteroides/efeitos dos fármacos , Intestinos/microbiologia , Testes de Sensibilidade MicrobianaRESUMO
BACKGROUND: Periodic monitoring of antimicrobial resistance trends of clinically important anaerobic bacteria such as Bacteroides fragilis group organisms is required. We determined the antimicrobial susceptibilities of clinical isolates of B. fragilis group organisms recovered from 2009 to 2012 in a tertiary-care hospital in Korea. METHODS: A total of 180 nonduplicate clinical isolates of B. fragilis group organisms were collected in a tertiary care hospital. The species were identified by conventional methods: the ATB 32A rapid identification system (bioMerieux, France) and the Vitek MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (bioMerieux). Antimicrobial susceptibility was determined by the CLSI agar dilution method. RESULTS: Imipenem and meropenem resistance rates were 0-6% for B. fragilis group isolates. The rate of resistance to piperacillin-tazobactam was 2% for B. fragilis and 0% for other Bacteroides species, but 17% for B. thetaiotaomicron isolates. High resistance rates to piperacillin (72% and 69%), cefotetan (89% and 58%), and clindamycin (83% and 69%) were observed for B. thetaiotaomicron and other Bacteroides spp. The moxifloxacin resistance rate was 27% for other Bacteroides spp. The MIC50 and MIC90 of tigecycline were 2-4 microg/mL and 8-16 microg/mL, respectively. No isolates were resistant to chloramphenicol or metronidazole. CONCLUSIONS: Imipenem, meropenem, chloramphenicol, and metronidazole remain active against B. fragilis group isolates. Moxifloxacin and tigecycline resistance rates are 2-27% and 8-15% for B. fragilis group isolates, respectively.
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Humanos , Anti-Infecciosos/farmacologia , Infecções por Bacteroides/microbiologia , Bacteroides fragilis/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Imipenem/farmacologia , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Ácido Penicilânico/análogos & derivados , Piperacilina/farmacologia , República da Coreia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Centros de Atenção Terciária , Tienamicinas/farmacologiaRESUMO
BACKGROUND: By conventional methods, the identification of anaerobic bacteria is more time consuming and requires more expertise than the identification of aerobic bacteria. Although the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems are relatively less studied, they have been reported to be a promising method for the identification of anaerobes. We evaluated the performance of the VITEK MS in vitro diagnostic (IVD; 1.1 database; bioMerieux, France) in the identification of anaerobes. METHODS: We used 274 anaerobic bacteria isolated from various clinical specimens. The results for the identification of the bacteria by VITEK MS were compared to those obtained by phenotypic methods and 16S rRNA gene sequencing. RESULTS: Among the 249 isolates included in the IVD database, the VITEK MS correctly identified 209 (83.9%) isolates to the species level and an additional 18 (7.2%) at the genus level. In particular, the VITEK MS correctly identified clinically relevant and frequently isolated anaerobic bacteria to the species level. The remaining 22 isolates (8.8%) were either not identified or misidentified. The VITEK MS could not identify the 25 isolates absent from the IVD database to the species level. CONCLUSIONS: The VITEK MS showed reliable identifications for clinically relevant anaerobic bacteria.
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Humanos , Bactérias Anaeróbias/genética , Técnicas de Tipagem Bacteriana/instrumentação , Líquidos Corporais/microbiologia , Bases de Dados Genéticas , RNA Ribossômico 16S/análise , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
This erratum is being published to correct the printing error on page 96.
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Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated.
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Humanos , Antibacterianos/farmacologia , Povo Asiático , Escherichia coli/efeitos dos fármacos , Laboratórios , Testes de Sensibilidade Microbiana/métodos , Pseudomonas aeruginosa/efeitos dos fármacos , Controle de Qualidade , Valores de Referência , República da Coreia , Coloração e Rotulagem , Staphylococcus aureus/efeitos dos fármacosRESUMO
The trends and types of carbapenemase-producing Gram-negative bacilli were analyzed from clinical specimens collected between 2005 and 2012 at a Korean teaching hospital. The proportions of carbapenem-resistant Acinetobacter spp. increased markedly to 66%. Metallo-beta-lactamase producers significantly decreased and the majority shifted from the bla(VIM-2) type to the bla(IMP-1) type.
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Humanos , Acinetobacter/classificação , Infecções por Acinetobacter/tratamento farmacológico , Antibacterianos/farmacologia , Proteínas de Bactérias , Carbapenêmicos/farmacologia , Resistência Microbiana a Medicamentos , Bactérias Gram-Negativas/efeitos dos fármacos , Incidência , Testes de Sensibilidade Microbiana/tendências , Vigilância da População , Pseudomonas/classificação , República da Coreia/epidemiologia , beta-Lactamases/biossínteseRESUMO
Emerging resistance to trimethoprim/sulfamethoxazole (SXT) poses a serious threat to the treatment of Stenotrophomonas maltophilia infections. We determined the prevalence and molecular characteristics of acquired SXT resistance in recent clinical S. maltophilia isolates obtained from Korea. A total of 252 clinical isolates of S. maltophilia were collected from 10 university hospitals in Korea between 2009 and 2010. Antimicrobial susceptibility was determined by using the CLSI agar dilution method. The sul1, sul2, and sul3 genes, integrons, insertion sequence common region (ISCR) elements, and dfrA genes were detected using PCR. The presence of the sul1 gene and integrons was confirmed through sequence analysis. Among the 32 SXT-resistant isolates, sul1 was detected in 23 isolates (72%), all of which demonstrated high-level resistance (> or =64 mg/L) to SXT. The sul1 gene (varying in size and structure) was linked to class 1 integrons in 15 of the 23 isolates (65%) harboring this gene. None of the SXT-susceptible isolates or the SXT-resistant isolates with a minimum inhibitory concentration of 4 and 8 mg/L were positive for sul1. Moreover, the sul2, sul3, and dfrA genes or the ISCR elements were not detected. The sul1 gene may play an important role in the high-level SXT resistance observed in S. maltophilia.
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Humanos , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Farmacorresistência Bacteriana/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Integrons/genética , Testes de Sensibilidade Microbiana , Stenotrophomonas maltophilia/efeitos dos fármacos , Combinação Trimetoprima e Sulfametoxazol/farmacologiaRESUMO
BACKGROUND: In general, higher resistance rates are observed among intensive care unit (ICU) isolates than non-ICU isolates. In this study, resistance rates of isolates from ICUs and non-ICUs were compared using the data generated from 20 hospitals in Korea. METHODS: Susceptibility data were collected from 20 hospitals participating in the Korean Nationwide Surveillance of Antimicrobial Resistance (KONSAR) program. Duplicate isolates were excluded from the analysis. The resistance rates did not include intermediate susceptibility. RESULTS: The most prevalent bacteria in the ICUs were Staphylococcus aureus (21%) and Acinetobacter spp. (19%), and those in non-ICU were Escherichia coli (27%) and S. aureus (14%). The resistance rates were higher in ICUs than in non-ICUs at 84% and 58% for methicillin-resistant S. aureus, 86% and 70% for methicillin-resistant coagulase-negative Staphylcoccus (CNS), 34% and 19% for vancomycin-resistant Enterococcus faecium, 38% and 19% for cefotaxime-resistant E. coli, 45% and 25% for cefotaxime-resistant Klebsiella pneumoniae, 42% and 24% for ceftazidime-resistant Enterobacter cloacae, 29% and 11% for ceftazidime-resistant Serattia marcescens, 83% and 44% for imipenem-resistant Acinetobacter spp., and 32% and 17% for imipenem-resistant Pseudomonas aeruginosa, respectively. CONCLUSION: The most prevalent bacteria in ICUs were S. aureus, CNS, and Acinetobacter spp., and high multi-drug resistance rates were observed in the Acinetobacter isolates. Therefore, infection control should be practiced in ICUs to prevent infections caused by multi-drug resistant bacteria.
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Acinetobacter , Bactérias , Resistência a Múltiplos Medicamentos , Enterobacter cloacae , Enterococcus faecium , Escherichia coli , Controle de Infecções , Unidades de Terapia Intensiva , Klebsiella pneumoniae , Coreia (Geográfico) , Resistência a Meticilina , Pseudomonas aeruginosa , Staphylococcus aureusRESUMO
BACKGROUND: Acinetobacter spp. is an important nosocomial pathogen for which increasing resistance to multiple antimicrobial agents has been observed. Prevalence of multidrug-resistant (MDR) Acinetobacter spp. in the intensive care unit (ICU) at a teaching hospital in Korea started to increase in 2008. The aim of this study was to determine the source of pathogen spread and to characterize the emerging strains at an early stage of outbreak. METHODS: Samples from respiratory instruments and fomites in the ICUs, as well as from the healthcare workers, were cultured to identify the sources of MDR Acinetobacter spp. Antimicrobial susceptibility was determined by the CLSI disk diffusion method. Pulsed field gel electrophoresis (PFGE) was performed for clinical and environmental isolates in order to determine clonality. Carbapenemase genes were detected by multiplex PCR. Infection control measures including peer-monitoring of hand washing, environmental cleaning and standard precautions were enforced. RESULTS: Among the samples from the ICU tools (105) and healthcare worker's hands (44), 31 (30%) and 2 (5%) respective samples yielded MDR Acinetobacter spp. Among the environmental samples, 90% were from respiratory-related equipment. The majority of clinical and environmental MDR Acinetobacter spp. (44/55) belonged to the pulsotype A. baumannii and carried both bla(OXA-51)-like and bla(OXA-23)-like genes. Even though infection-control measures were enforced, prevalence of MDR Acinetobacter spp. continues to increase. CONCLUSION: An outbreak of MDR Acinetobacter spp. in a Korean hospital was caused by A. baumannii carrying the bla(OXA-23)-gene and was correlated with contaminated respiratory-related instruments in the ICUs. More intensive measures for nosocomial infection control are needed for successful prevention of Acinetobacter spread in hospitals.
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Acinetobacter , Anti-Infecciosos , Infecção Hospitalar , Atenção à Saúde , Difusão , Surtos de Doenças , Eletroforese em Gel de Campo Pulsado , Fômites , Mãos , Desinfecção das Mãos , Hospitais de Ensino , Controle de Infecções , Unidades de Terapia Intensiva , Coreia (Geográfico) , Reação em Cadeia da Polimerase Multiplex , PrevalênciaRESUMO
BACKGROUND: Antimicrobial surveillance is important for providing an up-to-date understanding of the epidemiology of antimicrobial resistance and for creating a forum for rational drug development. In this study, we analyzed antimicrobial test data generated in 2011 by hospitals and commercial laboratories participating in the Korean Nationwide Surveillance of Antimicrobial Resistance program (KONSAR). MATERIALS AND METHODS: Data on the results of susceptibility tests conducted in 32 hospitals and two commercial laboratories were analyzed. Data on isolates from patients admitted to an intensive care unit (ICU) and those admitted to other wards were compared. Intermediate susceptibility was not analyzed and duplicate isolates were excluded. RESULTS: Escherichia coli was the most prevalent organism identified in both the hospital and commercial laboratories. Among the hospital isolates, methicillin-resistant Staphylococcus aureus (MRSA), penicillin G-non-susceptible Streptococcus pneumoniae, and ampicillin-resistant Enterococcus faecium remained as prevalent as they were in 2009. The proportion of vancomycin-resistant E. faecium (VR-EFM) slightly decreased from 29% in 2009 to 23% in 2011. Resistance rates of Klebsiella pneumoniae to ceftazidime, cefoxitin, fluoroquinolone, and amikacin were 24%, 14%, 27%, and 8%, respectively. Resistance rates of Pseudomonas aeruginosa to fluoroquinolone, ceftazidime, imipenem, and amikacin were 33%, 20%, 22%, and 16%, respectively, whereas those of Acinetobacter spp. resistance were 71%, 66%, 64, and 51%, respectively. The prevalence of oxyimino-cephalosporin-resistant E. coli and K. pneumoniae, carbapenem-resistant Acinetobacter spp. and P. aeruginosa, MRSA, and VR-EFM among ICU isolates was higher than those among non-ICU isolates. Extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae, imipenem-resistant P. aeruginosa, and VR-EFM were more prevalent among isolates from commercial laboratories than those from hospitals. Resistance rates of K. pneumoniae to ceftazidime and amikacin decreased from 32% and 24% in 2005 to 24% and 8% in 2011, respectively. The resistance rate of P. aeruginosa to amikacin decreased from 22% in 2005 to 16% in 2011. The proportion of imipenem-resistant Acinetobacter spp. increased from 16% in 2005 to 64% in 2011. CONCLUSIONS: The prevalence of MRSA, penicillin G-non-susceptible S. pneumoniae, and ampicillin-resistant E. faecium among clinical isolates tested in laboratories remained high. Multidrug resistance was more prevalent among isolates from ICUs. The prevalence of ceftazidime-resistant and amikacin-resistant K. pneumoniae and amikacin-resistant P. aeruginosa decreased after 2005, while the prevalence of imipenem-resistant Acinetobacter spp. increased.
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Humanos , Acinetobacter , Amicacina , Cefoxitina , Ceftazidima , Resistência a Múltiplos Medicamentos , Enterococcus faecium , Epidemiologia , Escherichia coli , Imipenem , Unidades de Terapia Intensiva , Klebsiella pneumoniae , Coreia (Geográfico) , Staphylococcus aureus Resistente à Meticilina , Penicilinas , Pneumonia , Prevalência , Pseudomonas aeruginosa , Salmonella , Staphylococcus , Streptococcus pneumoniaeRESUMO
We report a case of CTX-M-55-type extended-spectrum beta-lactamase (ESBL)-producing Shigella sonnei infection in a 27-year-old Korean woman who had traveled to China. The patient was admitted to the hospital due to abdominal pain, watery diarrhea, and fever (39.3degrees C). S. sonnei was isolated from her stool specimens, and the pathogen was found to be resistant to cefotaxime due to CTX-M-55-type ESBL. Insertion sequence (IS)Ecp1 was found upstream of the blaCTX-M-55 gene. The blaCTX-M-55 gene was transferred from the S. sonnei isolate to an Escherichia coli J53 recipient by conjugation. Pulsed-field gel electrophoresis and Southern blotting revealed that the blaCTX-M-55 gene was located on a plasmid of approximately 130 kb.
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Adulto , Feminino , Humanos , Antibacterianos/farmacologia , Povo Asiático , Cefotaxima/farmacologia , China , Farmacorresistência Bacteriana/efeitos dos fármacos , Disenteria Bacilar/diagnóstico , Eletroforese em Gel de Campo Pulsado , Escherichia coli/metabolismo , Fezes/microbiologia , Plasmídeos/química , República da Coreia , Shigella sonnei/enzimologia , Viagem , beta-Lactamases/genéticaRESUMO
BACKGROUND: Antimicrobial resistance of Neisseria gonorrhoeae has become a serious problem worldwide, and ceftriaxone non-susceptible isolates have been recently reported from Japan and Europe. In this study, we evaluated the antimicrobial susceptibilities and molecular epidemiological characteristics of isolates from Korea in 2013. METHODS: Sixty strains of N. gonorrhoeae were collected from Korean patients and prostitutes. Antimicrobial susceptibility was tested by the agar dilution and disk diffusion methods. N. gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed in order to determine the molecular epidemiologic relatedness. RESULTS: All of isolates were non-susceptible to penicillin G and tetracycline, and the rate of ciprofloxacin-resistant isolates was 95% in 2013. The MICs of ceftriaxone were within the susceptible range for all isolates, but one isolate non-susceptible to cefixime (MIC=0.5 microg/mL) was encountered. The isolates with decreased susceptibility (MIC< or =0.12 microg/mL) to cefixime or ceftriaxone accounted for 10% and 14% of the isolates tested, respectively. In NG-MAST analysis, 40 different STs were encountered among the 59 isolates. Isolates that belonged to tbpB110 showed higher cefixime and ceftriaxone MICs (0.12-0.5 microg/mL) as well as cefixime resistance. CONCLUSION: Most of the N. gonorrhoeae isolates showed susceptibility to spectinomycin and cephalosporins. Due to the emergence of isolates that are non-susceptible to cefixime and the prevalence of isolates with the tbpB110 allele belonging to ST1407, which cause cefixime and ceftriaxone treatment failure in successful global clones of N. gonorrhoeae, a continuous nationwide antimicrobial surveillance program is required to monitor the emergence of cephalosporin resistance in N. gonorrhoeae.
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BACKGROUND: Gram-negative bacilli can be stored in cystine tryptic agar (CTA) at room temperature for over 1 year, but we experienced a loss of imipenem resistance among VIM-2-producing isolates. The aims of this study were to determine the frequency of loss of IMP-1 and VIM-2 genes during storage in CTA at room temperature and to document any change in the MIC of antimicrobial agents and the location of the gene. METHODS: Bacteria were isolated from clinical specimens at Severance Hospital collected from 1995-2000. Modified Hodge and double disk synergy tests were performed for screening of MBL-production isolates, and blaIMP-1 and blaVIM-2 were detected by PCR. Loss of resistance was tested in CTA at room temperature. PFGE and hybridization using a blaVIM-2 probe were carried out to determine the location of the VIM-2 gene. RESULTS: When VIM-2- and IMP-1-producing strains of eight P. aeruginosa and two Acinetobacter spp. were stored in CTA at room temperature, some isolates lost imipenem resistance after 3 days and 90% lost resistance after 15 weeks. Loss of resistance genes resulted in a decrease of the MIC of imipenem from 32-128 mug/mL to 0.5-8 mug/mL for P. aeruginosa, and from 32 mug/mL to 0.25-4 mug/mL for Acinetobacter spp. Hybridization of I-CeuI and S1-digested and PFGE suggested that VIM-2 genes are located on approximately 50-100 kb or 400 kb plasmids. CONCLUSION: Isolates may lose resistance genes when stored in CTA at room temperature. Therefore, it is necessary for MBL-production tests including the Modified Hodge test and double disk synergy test and detection of MBL genes.
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Acinetobacter , Ágar , Anti-Infecciosos , Bactérias , Carbapenêmicos , Quimera , Cistina , Imipenem , Programas de Rastreamento , Reação em Cadeia da Polimerase , Entorses e DistensõesRESUMO
BACKGROUND: Trends in the isolation of enteropathogenic bacteria may differ depending on environmental sanitation. The aims of this study were to determine trends in the isolation and antimicrobial resistance patterns of enteropathogenic bacteria over the last 10 years. METHODS: We analyzed stool cultures of Salmonella spp., Shigella spp., Plesiomonas shigelloides, Yersinia spp., Vibrio spp., and Campylobacter spp. collected at Severance Hospital between 2001 and 2010. Antimicrobial susceptibility testing was performed using the disk diffusion method for nontyphoidal Salmonella (NTS) and Campylobacter. RESULTS: The number of specimens for stool culture significantly increased from 13,412 during 1969-1978 to 60,714 over the past 10 years, whereas the ratio of positive specimens significantly decreased from 12.9% (1,732) to 1.1% (648). The proportion of Salmonella Typhi decreased from 97.2% in 1969-1978 to 0.8% in 2001-2010, whereas the proportion of NTS increased from 2.8% to 99.2%. The proportion of Shigella among all enteric pathogens was over 50% from 1969 to 1983, while only seven strains were isolated from 2001 to 2010, with the exception of one outbreak. Campylobacter is the second most prevalent organism. The rates of susceptibility to ampicillin and cotrimoxazole were 61% and 92%, respectively, for NTS isolated from 2006 to 2010. The ciprofloxacin susceptibility rate was 79.5% for Campylobacter between 2006 and 2010. CONCLUSION: The number of isolates of Salmonella Typhi and Shigella significantly decreased, while the proportion of NTS and Campylobacter increased. Continuous monitoring of ciprofloxacin-resistant Campylobacter isolates is necessary.
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Ampicilina , Bactérias , Campylobacter , Ciprofloxacina , Difusão , Plesiomonas , Salmonella , Salmonella typhi , Saneamento , Shigella , Atenção Terciária à Saúde , Combinação Trimetoprima e Sulfametoxazol , Vibrio , YersiniaRESUMO
The aim of this study was to determine antimicrobial susceptibility of recent clinical Stenotrophomonas maltophilia isolates from Korea, and to compare the activity levels of several combinations of antimicrobials. A total of 206 non-duplicate clinical isolates of S. maltophilia was collected in 2010 from 11 university hospitals. Antimicrobial susceptibility testing was performed using the Clinical Laboratory Standards Institute agar dilution method. In vitro activity of antimicrobial combinations was tested using the checkerboard method. The susceptibility rates to trimethoprim-sulfamethoxazole and minocycline were 96% and 99%, respectively. The susceptibility rate to levofloxacin was 64%. All of four antimicrobial combinations showed synergy against many S. maltophilia isolates. A combination of trimethoprim-sulfamethoxazole plus ticarcillin-clavulanate was most synergistic among the combinations. None of the combinations showed antagonistic activity. Therefore, some of the combinations may be more useful than individual drugs in the treatment of S. maltophilia infection. Further clinical studies are warranted to validate our in vitro test results.
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Humanos , Anti-Infecciosos/farmacologia , Infecções por Bactérias Gram-Negativas/microbiologia , Hospitais Universitários , Testes de Sensibilidade Microbiana , Minociclina/farmacologia , Ofloxacino/farmacologia , República da Coreia , Stenotrophomonas maltophilia/efeitos dos fármacos , Combinação Trimetoprima e Sulfametoxazol/farmacologiaRESUMO
BACKGROUND: Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been used for the identification of bacteria worldwide. To our knowledge, the evaluation of MALDI-TOF MS for the identification of bacteria in Korea has not been studied. In this paper we compared the identification results of aerobic bacteria using MALDI-TOF MS to those results using conventional biochemical methods. METHODS: We evaluated the performance of a MALDI-TOF MS system (Bruker Daltonics, Leipzig, Germany) on consecutive aerobic isolates collected from January to February of 2011 which were identified using conventional methods (biochemical testing and commercial identification kits). Either directly smearing onto the target plate or protein extraction methods were additionally used if no reliable or discordant results were obtained. RESULTS: Among 523 isolates tested, 506 (97%) isolates had valid scores (> or =2.0), 11 (2%) isolates gave intermediate scores (1.7 or =2.0) by MALDI-TOF MS, the identification matched at the species level in 486 (96%) isloates, matched at the genus level in 17 (3%) isloates, and was discordant at the genus and species levels in 3 (1%) isloates. CONCLUSION: The overall matching rate at the species level of MALDI-TOF MS was very high. When MALDI-TOF MS did not yield reliable results by direct smear, additional direct smears or protein extraction methods could be used to obtain better results. Our results showed that MALDI-TOF MS is a very useful method for the identification of aerobic bacteria isolated in clinical microbiology laboratories.
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Bactérias , Bactérias Aeróbias , Coreia (Geográfico) , Espectrometria de MassasRESUMO
Infection with Clostridium difficile is a growing concern because of the increasing prevalence and spread of nosocomial infections. Emergence of the hypervirulent 027/NAP1/BI strain is also notable. Existing diagnostic methods have low sensitivity or are time-consuming. Therefore, establishing a rapid and accurate microbiological diagnostic assay is needed. We evaluated the Xpert C. difficile assay (Xpert CD assay; Cepheid, USA) to detect toxigenic C. difficile. This assay is a real-time multiplex PCR assay that can be used to detect toxigenic C. difficile strains and differentiate the C. difficile presumptive 027/NAP1/BI strain. A total of 253 loose stool specimens were collected and toxigenic cultures, VIDAS C. difficile A & B assays (VIDAS CDAB assay; bioMerieux, France), and the Xpert CD assay were performed. In comparison to toxigenic cultures, the sensitivity, specificity, and positive and negative predictive values were 100%, 94.6%, 83.1%, and 100%, respectively, for the Xpert CD assay and 40.8%, 98.0%, 100%, and 88.9%, respectively, for VIDAS CDAB assay. Because of the low prevalence of the PCR ribotype 027 in Korea, the evaluation of the usefulness of the Xpert CD assay for screening for the 027 strain was limited. The Xpert CD assay provides great sensitivity in diagnosing toxigenic C. difficile infection. In addition, this method has excellent usability because it is simple and fast.