Subject(s)
Acinetobacter baumannii/enzymology , Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/enzymology , Acinetobacter calcoaceticus/genetics , Bacterial Proteins/genetics , Drug Resistance, Bacterial , beta-Lactamases/genetics , Acinetobacter baumannii/classification , Acinetobacter calcoaceticus/classification , Anti-Bacterial Agents/pharmacology , Molecular Sequence Data , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 23S/genetics , SingaporeABSTRACT
OBJECTIVE: To compare the incidence of carbapenemase genes in Acinetobacter baumannii between two time periods. METHODS: We studied 114 isolates of imipenem-resistant A. baumannii collected over two 5 month periods (in 1996 and 2001). Isolates showing carbapenemase activity by plate bioassay were screened for carbapenemase genes using PCR. Chromosomal DNA from strains carrying carbapenemase genes was subjected to PFGE after digestion with ApaI. RESULTS: The incidence of imipenem-resistant A. baumannii in our hospital rose from 1.1 per 1000 admissions in 1996 to 2.3 per 1000 admissions in 2001. However, the number of carbapenemase-producing A. baumannii rose only slightly in 2001 (0.8 per 1000 admissions) compared to 1996 (0.5 per 1000 admissions). Of 44 isolates with carbapenemase activity, 4 isolates carried bla(IMP-4), 5 carried bla(OXA-58), and 40 carried bla(OXA-23). In addition, most isolates carried a bla(OXA-51)-type beta-lactamase gene. All strains with bla(IMP-4), also carried bla(OXA-58) and bla(PSE-1), but not bla(OXA-51)-type beta-lactamase genes. PCR analysis repeated on seven recent isolates of susceptible A. baumannii showed only the presence of bla(OXA-51)-type beta-lactamase genes. A total of five novel bla(OXA-51)-type beta-lactamase genes (bla(OXA-88),-91,-93,-94, and -95) and one new bla(OXA-58)-type beta-lactamase gene (bla(OXA-96)) were found. CONCLUSIONS: The incidence of carbapenemase genes did not vary significantly between the two study periods. There is a wide diversity of OXA genes in A. baumannii in Singapore. The most common carbapenemase gene found in our study was bla(OXA-23).
Subject(s)
Acinetobacter baumannii/enzymology , beta-Lactamases/isolation & purification , Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Carbapenems/pharmacology , Drug Resistance, Bacterial , Hospitals, General , Humans , Microbial Sensitivity Tests , Molecular Sequence Data , Reverse Transcriptase Polymerase Chain Reaction , Singapore , beta-Lactamases/genetics , beta-Lactamases/metabolismABSTRACT
We report the first outbreak of vancomycin-resistant Enterococcus faecium colonization and infection among inpatients in the hematology ward of an acute tertiary care public hospital in Singapore. Two cases of bacteremia and 4 cases of gastrointestinal carriage were uncovered before implementation of strict infection control measures resulted in control of the outbreak.
Subject(s)
Disease Outbreaks , Enterococcus faecium/pathogenicity , Gram-Positive Bacterial Infections/epidemiology , Vancomycin Resistance , Adult , Aged , Electrophoresis, Gel, Pulsed-Field , Enterococcus faecium/isolation & purification , Female , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/mortality , Humans , Singapore/epidemiologySubject(s)
Anti-Bacterial Agents/pharmacology , Staphylococcal Infections/epidemiology , Staphylococcus aureus/drug effects , Vancomycin Resistance , Vancomycin/pharmacology , Aged , Bacteremia/drug therapy , Bacteremia/microbiology , Humans , Male , Methicillin Resistance , Microbial Sensitivity Tests , Pneumonia, Bacterial/drug therapy , Pneumonia, Bacterial/microbiology , Singapore/epidemiology , Staphylococcal Infections/microbiologyABSTRACT
Thirty-six isolates of carbapenem-resistant Pseudomonas aeruginosa were studied. Pulsed-field gel electrophoresis revealed the presence of two clones. One clone carried a bla(IMP-1) gene identical to that first described in Japan. The other clone carried a bla(IMP-1) variant containing four silent mutations. One isolate with a unique pulsed-field gel electrophoresis pattern contained bla(IMP-7).
Subject(s)
Hospitals , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/genetics , beta-Lactam Resistance , beta-Lactamases/metabolism , Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Electrophoresis, Gel, Pulsed-Field , Humans , Microbial Sensitivity Tests , Molecular Sequence Data , Mutation , Pseudomonas Infections/microbiology , Pseudomonas Infections/transmission , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/enzymology , Sequence Analysis, DNA , Singapore/epidemiology , beta-Lactamases/geneticsSubject(s)
Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/enzymology , beta-Lactam Resistance/genetics , beta-Lactamases/genetics , Base Sequence , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Enterobacteriaceae/genetics , Enterobacteriaceae Infections/drug therapy , Humans , Isoelectric Point , Microbial Sensitivity Tests , Molecular Sequence Data , Polymerase Chain Reaction , Sequence Analysis, DNA , Singapore , beta-Lactamases/metabolismABSTRACT
Four carbapenem-resistant Pseudomonas spp. were isolated from patients in Singapore. One Pseudomonas putida isolate contained a bla(IMP-1) identical to that first described in Japan. The sequence of a variant bla(IMP-1) in Pseudomonas fluorescens contained four silent mutations compared with the original sequence. The remaining P. putida isolates contained bla(VIM-6), a novel VIM gene variant.
