Current susceptibility patterns for H. influenzae and M. catarrahlis isolates from Europe: findings of the 2007 GLOBAL surveillance program

Abstract number: P1184

Brown N., Thornsberry C., Draghi D., Aranza M., Pillar C., Sahm D.

Objective:Haemophilus influenzae (HI) and Moraxella catarrhalis (MC) associated with community-acquired respiratory tract infections can become resistant to commonly prescribed agents and these resistance (R) rates can vary according to regional distributions. The GLOBAL Surveillance (SUR) initiative was undertaken to track R patterns among respiratory pathogens. This study tracks the resistance of HI and MC collected as part of GLOBAL '07 to empirically used oral agents.

Methods: During 2007, 858 HI and 163 MC isolates from patient specimens were collected from 6 European (EU) countries: Belgium, France, Germany, Italy, Spain (SPN), and the United Kingdom. All isolates were centrally tested by broth microdilution according to CLSI M7-A7 and the results were interpreted according to CLSI M100-S17. Data were analysed according to b-lactamase (BL) status as positive (+) or negative (-).

Results: For all EU countries combined, 130 HI isolates were BL+ (15.2%) and 728 isolates were BL- (84.8%). Overall, current MIC90s (mg/L) were >8 for ampicillin (AMP), 0.03 for levofloxacin (LFX), and >4 for trimethoprim-sulfamethoxazole (SXT), regardless of BL phenotype, except for BL- isolates against AMP (MIC90, 0.5 mg/L). The current overall percent R among the oral agents were 15.4% AMP, 0.1% LFX, and 18.3% SXT. By country, LFX retained potent activity against HI, regardless of phenotype, based on MIC90s (0.015–0.03 mg/L for all) and susceptibility (%S) was 100% for all, except SPN (overall %S=99.4), where 1 isolate was non-susceptible. One HI isolate was found to be BL- ampicillin-resistant. For all EU countries combined, 160 MC isolates were BL+ (98.2%), with <2% BL-. With the exception of ampicillin and cefuroxime, all agents were highly active against the tested MC, with 100% susceptibility rates.

Conclusion: Among HI, R to SXT and AMP (BL mediated) was prevalent throughout EU. In contrast, current %S to LFX remains high throughout EU against HI. Against MC, isolates are 100% susceptible to all agents, with the exception of ampicillin and cefuroxime, regardless of BL+ rates among MC which have reached 98%. Continued SUR is warranted to monitor any changes that may occur among these respiratory pathogens to help guide empiric therapy for community-acquired respiratory tract infections.