title: Antibiotic resistance and serotypes of Streptococcus pneumoniae at Birmingham Public Health Laboratory, 1989-94.
abstract: Antibiotic resistance of 1515 consecutive laboratory isolates of Streptococcus pneumoniae between 1989 and 1994 was analyzed. Overall, 39 (2.6%) isolates were resistant to penicillin, 102 (6.7%) resistant to erythromycin and 52 (3.4%) resistant to tetracycline. There was a higher proportion of penicillin resistant isolates from sterile sites compared with "non-sterile sites" (5% vs. 2.2%; P < 0.02). This same pattern occurred with erythromycin (12.5% vs. 5.6%; P < 0.001). From 1989-90 to 1993-94 the penicillin resistance rate increased from 0.8% to 8% and the erythromycin from 5.7% to 8.4%, whereas the tetracycline resistance rate fell from 3.7% to 2.8%. The increase in resistance to penicillin largely occurred in the final 12 months of this study period. One hundred and fifty isolates (9.9%) were serotyped, including isolates from sterile sites and those with penicillin resistance. The commonest serotypes of penicillin-sensitive pneumococci were 14, 19, 9 and 6. The majority of penicillin-resistant pneumococci (PRP) were of serotype 9 (64%) followed by 6, 23 and 19. Overall 95% of these isolates were of serotypes represented in the 23-valent pneumococcal polysaccharide vaccine (Pneumovax II). PRP were more likely to have resistance to erythromycin (23%) or tetracycline (23%) compared to penicillin-sensitive pneumococci (6% and 3% respectively). Most of the PRP were isolated from patients aged over 50 years including 11 isolates from blood cultures of patients with pneumonia or septicaemia. There was a possible epidemiological association between four patients with PRP but surveillance cultures of hospital contacts revealed no extra cases. These results show a worrying increase in infections due to PRP which has implications for clinical and laboratory staff in the diagnosis and treatment of serious pneumococcal infections.
authors.affiliation: Public Health Laboratory, Birmingham Heartlands Hospital, U.K.
authors.forename: T C
authors.initials: TC
authors.lastname: Boswell
authors.forename: D
authors.initials: D
authors.lastname: Frodsham
authors.forename: K J
authors.initials: KJ
authors.lastname: Nye
authors.forename: E G
authors.initials: EG
authors.lastname: Smith
mesh_terms: D006801:Humans; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology; D010403:Penicillin Resistance; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects*; D013997:Time Factors
chemical_list: D010068:Oxacillin