Increased resistance to beta-lactams in a Klebsiella pneumoniae strain: role of a deletion downstream of the Pribnow box in the blaSHV-1 promoter.
Two hundred and five isolates of Klebsiella pneumoniae were collected from Nantes University Hospital in 2002. A new 30bp deletion was detected downstream of the -10 box of the SHV-1 promoter in a clinical K. pneumoniae isolate with a high amoxicillin/clavulanic acid minimum inhibitory concentration. Reverse transcription polymerase chain reaction revealed increased transcription of bla(SHV-1) mRNA. All conjugation mating assays failed. This new promoter was cloned upstream of the cat gene of the reporter plasmid pKK232-8 and compared with previously described bla(SHV-1) promoters. The deletion induced a 15-fold increase in promoter strength compared with the usual weak promoter. This study reports a new genetic event that increases bla(SHV-1) chromosomal gene expression, which may be of clinical relevance when associated with porin deficiency.
Corvec
Stéphane
S
Laboratoire de Bactériologie-Virologie, Hygiène Hospitalière, CHU de Nantes, 9 quai Moncousu, 44093 Nantes Cedex 01, France. stephane.corvec@chu-nantes.fr
Caroff
Nathalie
N
Cosano
Daniel
D
Dauvergne
Sandie
S
Drugeon
Henri
H
Reynaud
Alain
A
D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007710:Klebsiella Infections; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology*
D004269:DNA, Bacterial; D047090:beta-Lactams; C054882:beta-lactamase PIT-2; D001618:beta-Lactamases