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- Title
Ampicillin resistance in Haemophilus influenzae: identification of resistance mechanisms.
- Authors
Reid, Alison J.; Simpson, Iain N.; Harper, Paul B.; Amyes, Sebastian G.B.; Reid, A J; Simpson, I N; Harper, P B; Amyes, S G
- Abstract
The incidence and mechanisms of ampicillin resistance (MIC greater than 1 mg/l) were investigated in 105 clinical isolates of Haemophilus influenzae collected in Edinburgh during 1983/4. Fifteen (14.3%) ampicillin-resistant strains were identified and these were non-serotypable and comprised six biotypes. Isoelectric focusing and beta-lactamase-inhibition studies demonstrated that production of the TEM-1 beta-lactamase was the principal mechanism of resistance in nine (60%) strains. Radiolabelling revealed that one beta-lactamase-positive strain also had an unusual penicillin-binding protein (PBP) profit. No beta-lactamase activity was detected in the other six (40%) ampicillin-resistant strains. Two beta-lactamase-negative ampicillin-resistant strains had atypical PBP profiles. SDS-PAGE analysis showed that four beta-lactamase-negative ampicillin-resistant strains, including one with altered PBPs, exhibited outer membrane protein profiles which differed from those of sensitive strains of the same biotype. The ampicillin-resistance mechanism of the remaining strain could not be determined. Thus, several resistance mechanisms, either acting individually or in combination, are implicated in ampicillin resistance in H. influenzae.
- Subjects
BACTERIAL proteins; CARRIER proteins; CEPHALOSPORINS; COMPARATIVE studies; DRUG resistance in microorganisms; ELECTROPHORESIS; HAEMOPHILUS influenzae; HYDROLASES; RESEARCH methodology; MEDICAL cooperation; MEMBRANE proteins; MICROBIAL sensitivity tests; PROTEOLYTIC enzymes; RESEARCH; TRANSFERASES; EVALUATION research; AMPICILLIN; PHARMACODYNAMICS
- Publication
Journal of Antimicrobial Chemotherapy (JAC), 1987, Vol 20, Issue 5, p645
- ISSN
0305-7453
- Publication type
journal article