ABSTRACT
Over the past 20 years, some Enterobacteriaceae mainly Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis have demonstrated acquisition of plasmids secreting ESBL. CTX-M type ESBL have been isolated worldwide and their incidence has increased dramatically and is still increasing leading to a major therapeutic issue. Currently more than 150 allelic variants of CTX-M have been identified. These enzymes are classified in five major phylogenetic groups based on their gene sequences: CTX-M -1, CTX-M-2, CTX-M-8, CTX-M-9, CTX-M-25; two additional groups have been reported recently: CTX-M-74 and CTX-M-75. The important dissemination of these enzymes has led to an increased use of carbapenems. Their global community and nosocomial dissemination is often associated with a virulent E. coli clone ST131 producing CTX-M-15.
Subject(s)
Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/enzymology , beta-Lactamases/classification , Animals , Drug Resistance, Bacterial , Enterobacteriaceae/drug effects , Enterobacteriaceae/genetics , Enterobacteriaceae/isolation & purification , Enterobacteriaceae Infections/epidemiology , Genes, Bacterial , Humans , PlasmidsABSTRACT
Two carbapenem-resistant Klebsiella pneumoniae isolates producing the plasmid-encoded carbapenem-hydrolyzing OXA-48 were identified. These isolates, recovered from two patients hospitalized in two different hospitals in Tunisia in December 2010, were not clonally related. Molecular investigations showed that both isolates co-produced the narrow-spectrum ß-lactamases TEM-1 and SHV-1, together with the extended-spectrum ß-lactamase CTX--15.
Subject(s)
Anti-Bacterial Agents/metabolism , Carbapenems/metabolism , Klebsiella Infections/microbiology , Klebsiella pneumoniae/enzymology , Klebsiella pneumoniae/isolation & purification , beta-Lactamases/metabolism , Humans , Klebsiella pneumoniae/genetics , Microbial Sensitivity Tests , Plasmids , Tunisia , Urine/microbiology , beta-Lactamases/geneticsABSTRACT
PURPOSE: To study the resistance to third-generation cephalosporins in Providencia stuartii strain isolated from hospitalized patient in Tunisia and to identify the responsible genes MATERIALS AND METHODS: This strain was analysed by PCR and sequencing to identify the genes responsible for the ß-lactamase resistance phenotypes. The transferability of the phenotypes was tested by conjugation to Escherichia coli J53. The isoelectric point was determinate by isoelectrofocalisation. RESULTS: This resistance was carried by a 60 kb plasmid that encoded a ß-lactamase with a pI of 5.4. This ß-lactamase revealed identity with the blaTEM-1 gene encoding the TEM-1 ß-lactamase, except for a replacement of the Val residue at position 84 by Ile, and the Ala residue at position 184 by Val. These two mutations were encountered in TEM-116 ß-lactamase. CONCLUSION: This study demonstrates the ï¬rst description of TEM-116 in the P. stuartii species in the world and the ï¬rst one in a Tunisian hospital.
Subject(s)
Enterobacteriaceae Infections/microbiology , Providencia/enzymology , Providencia/isolation & purification , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Cephalosporins/pharmacology , Conjugation, Genetic , Escherichia coli/genetics , Gene Transfer, Horizontal , Hospitals , Humans , Plasmids , Polymerase Chain Reaction , Providencia/drug effects , Providencia/genetics , Sequence Analysis, DNA , Tunisia , beta-Lactam ResistanceABSTRACT
A collection of 20 multidrug-resistant Providencia stuartii isolates recovered from 2005 to 2009 at the Military Hospital of Tunis, Tunisia, was analysed. They all expressed the extended-spectrum ß-lactamase (ESBL) VEB-1a. The bla (VEB-1a) gene was plasmid-located and it was associated with complex genetic structures, including Re elements. Pulsed-field gel electrophoresis (PFGE) revealed a clonal relationship between all of these isolates. This study identified a nosocomial dissemination of an ESBL-producing P. stuartii clone in a Tunisian hospital over a long period of time.
