Increased incidence of ciprofloxacin resistance in penicillin-resistant pneumococci in Northern Ireland

• Published in: Journal of antimicrobial chemotherapy 1998-03, Vol.41 (3), p.420-421
• Main Authors: Goldsmith, C E, Moore, J E, Murphy, P G, Ambler, J E
• Format: Article
• Language: English
• Subjects: Anti-Infective Agents - pharmacology; Ciprofloxacin - pharmacology; Drug Resistance, Microbial; Drug Resistance, Multiple; Humans; Incidence; Microbial Sensitivity Tests; Northern Ireland - epidemiology; Penicillin Resistance; Penicillins - pharmacology; Pneumococcal Infections - epidemiology; Pneumococcal Infections - microbiology; Streptococcus pneumoniae - drug effects
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/41.3.420

Fuchs et al. recently reported that there was no correlation between quinolone susceptibility and penicillin susceptibility in Streptococcus pneumoniae. In a study of 209 recent US clinical isolates, there was no appreciable difference between the geometric mean MICs of ciprofloxacin and levofloxacin in relation to penicillin susceptibility. This group also previously showed that, contrary to popular belief, ciprofloxacin resistance is rare in S. pneumoniae, at least in vitro. They found that out of 698 strains, including 97 deliberately selected with MICs greater than or equal to 2 mg/L, only seven (1%) had an MIC greater than or equal to 4 mg/L and 86% were fully sensitive to ciprofloxacin with an MIC less than or equal to 1 mg/L. Similar figures were recently reported from the Alexander Project Collaborative Group. In a study of 953 strains from 15 centres in Western Europe and the USA, 90% of isolates had a MIC less than or equal to 1 mg/L in 1993. Whilst Barry & Fuchs question the degree of correlation between such in-vitro results and the in-vivo clinical outcome, a bacteriological eradication rate of 86% was recently reported for ciprofloxacin against S. pneumoniae.