ABSTRACT
Background: Metallo-ß-lactamases (MBL) confer high resistance to carbapenems in Pseudomonas aeruginosa (Psae). They are encoded in mobile elements of different genes (VIM, IMP, SMP, GIM), along with other resistance genes. Aim: To detect the presence of MBL in imipenem resistant Psae strains. Material and methods: Fifty-nine imipenem resistant Psae strains isolated from January 2004 to August 2005 in a University Clinical Hospital, were included. The presence of MBL was studied by Etest (phenotypic) and genotypic polymerase chain reaction (PCR) methods. To rule out a nosocomial outbreak, MBL positive strains, were studied by pulse field gel electrophoresis. Results: The presente of MBL was detected in eleven strains. AH were type VIM and were not clonally related. There was no concordance between phenotypic and genotypic MBL detecting methods. AH the strains were also multiresistant. Conclusions: The presence of MBL was detected in 19 percent of imipenem resistant Psae strains.
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Young Adult , Anti-Bacterial Agents/pharmacology , Imipenem/pharmacology , Pseudomonas Infections/drug therapy , Pseudomonas aeruginosa/enzymology , beta-Lactamases/genetics , Cross Infection/epidemiology , Cross Infection/genetics , Drug Resistance, Multiple, Bacterial/drug effects , Drug Resistance, Multiple, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Genes, Bacterial/drug effects , Genes, Bacterial/genetics , Imipenem/analysis , Microbial Sensitivity Tests , Polymerase Chain Reaction , Pseudomonas Infections/genetics , Pseudomonas aeruginosa/drug effects , Young Adult , beta-Lactam Resistance/drug effects , beta-Lactam Resistance/genetics , beta-Lactamases/analysisABSTRACT
To investigate the distribution of the genes of two major metallo-beta-lactamases (MBL; i.e., IMP and VIM) and class 1 integrons (intI) in the clinical imipenem-resistant Pseudomonas aeruginosa, a total of 65 isolates, from a university hospital in Sichuan between December 2004 and April 2005 were screened for MBL genes by PCR using primers specific for bla ( IMP-1 ), bla ( VIM ) and bla ( VIM-2 ) genes. The MBL-positive isolates were further assessed for class 1 integrons by PCR using specific primers. The nucleotide sequences of several PCR products were also determined. The results revealed that the bla ( VIM ) gene was found in 81.5% (53/65) of all isolates, bla ( VIM-2 ) gene was found in only 1 isolate and the intI gene was observed in 45.3% (24/53) of bla ( VIM )-positive isolates. One isolate carried simultaneously both bla ( IMP-1 ) and intI genes, and to the best of our knowledge this is the first report of such isolate in southwest China. These observations highlight that the genes for VIM beta-lactamase and class 1 integrons were predominantly present among the imipenem-resistant P. aeruginosa tested, confirming the current widespread threat of imipenem-resistant, integron-borne P. aeruginosa.
Subject(s)
Anti-Bacterial Agents/pharmacology , China , DNA Primers/chemistry , Drug Resistance, Bacterial , Gene Expression Regulation, Bacterial , Imipenem/pharmacology , Integrons , Microbial Sensitivity Tests , Models, Genetic , Pseudomonas Infections/genetics , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/metabolism , Sequence Analysis, DNA , beta-Lactamases/metabolismABSTRACT
The present work was carried out to study the genetic factors for multi-drug resistance in clinically isolated strains of Ps. aeruginosa. Conjugal transfer of resistance factor between Ps. aeruginosa strains was observed, while no transfer was found from Ps. aeruginosa to E. coli strains. The DNA analysis by gel-ectrophoresis revealed the presence of plasmid in one strain [AQ 003] only. As no conjugal transfer or presence of plasmid was observed in other strains, it is suggested that in these strains resistance may be of chromosomal or genetic origin