Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2008 Mar;61(3):509-14.
doi: 10.1093/jac/dkm523. Epub 2008 Feb 1.

Characterization of extended-spectrum beta-lactamase-producing isolates of Haemophilus parainfluenzae

Affiliations
Comparative Study

Characterization of extended-spectrum beta-lactamase-producing isolates of Haemophilus parainfluenzae

Stephen G Tristram et al. J Antimicrob Chemother. 2008 Mar.

Abstract

Objectives: To characterize the beta-lactam resistance mechanisms of two clinical isolates of cefotaxime-resistant Haemophilus parainfluenzae recovered from patients in South Africa.

Methods: The relatedness of isolates and plasmids was assessed using PFGE and restriction enzyme analysis, respectively. Plasmid-mediated and chromosomally integrated bla(TEM) genes and ftsI genes were sequenced, and the plasmid-mediated bla(TEM-15) was used to transform a range of control organisms.

Results: The two isolates were found to be unique according to PFGE, but had an identical 3.7 kb plasmid encoding a TEM-15 beta-lactamase. Both isolates also had substitutions in penicillin binding protein 3 (PBP3) consistent with substitutions known to exist in beta-lactamase-negative ampicillin-resistant (BLNAR) strains of Haemophilus influenzae. The cefotaxime MICs for control strains of H. influenzae, H. parainfluenzae and BLNAR H. influenzae transformed with the plasmid-mediated bla(TEM-15) were 1.0, 1.0 and 4.0 mg/L, respectively, compared with 16.0 and 8.0 mg/L, respectively, for the two parent H. parainfluenzae.

Conclusions: The high-level cefotaxime resistance in the H. parainfluenzae isolates was due to a combination of a plasmid-mediated TEM-15 extended-spectrum beta-lactamase with altered PBP3 probably contributing. Other contributing resistance mechanisms could not be excluded.

PubMed Disclaimer

Publication types

MeSH terms

LinkOut - more resources