Susceptibility patterns of bacterial isolates from hospitalised patients with respiratory tract infections (MOXIAKTIV Study)

The objective of this study was to determine: (i) the prevalence of resistance in current clinical isolates of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis and Klebsiella pneumoniae; (ii) the prevalence of production of extended-spectrum beta-lactamases (ESBLs) and methicillin resistance in S. aureus; and (iii) regional differences in the prevalence of ESBL production and clonality of K. pneumoniae isolates. Pathogens causing respiratory tract infections in hospitalised patients were prospectively collected from all over Germany. Drugs tested by Etest included moxifloxacin, levofloxacin, amoxicillin/clavulanic acid, cefuroxime, clarithromycin and penicillin G. ESBL production by K. pneumoniae was determined using cefotaxime/ceftazidime +/- clavulanic acid. Deutsches Institut fur Normung (German Institute for Standardisation)/European Committee on Antimicrobial Susceptibility Testing (DIN/EUCAST) breakpoints were used where applicable. Overall, 1859 pathogens were analysed. For all species tested the fluoroquinolones achieved the highest overall susceptibility rate (92.8%) compared with clarithromycin (60.5%), amoxicillin/clavulanic acid (85.7%) and cefuroxime (89.6%). From 438 K. pneumoniae isolates, 13.0% produced an ESBL. The ESBL prevalence was 38.8% in Eastern Germany with a trend towards clonality in some centres, but ranged from 4.7% to 7.1% in Southern, Northern and Western Germany. Among the methicillin-susceptible S. aureus isolates, 10.1% were moxifloxacin-and levofloxacin-resistant. Of the S. pneumoniae isolates, 99.3% were moxifloxacin-and levofloxacin-susceptible, 93.9% were penicillin G-susceptible and 85.7% were clarithromycin-susceptible. With a MIC90 value (minimal inhibitory concentration for 90% of the isolates) of 0.19 mg/L, moxifloxacin was more potent than levofloxacin (MIC90 = 1 mg/L) against S. pneumoniae. Haemophilus influenzae and M. catarrhalis were almost 100% susceptible to the quinolones; 100% of the M. catarrhalis but only 4.5% of the H. influenzae strains were clarithromycin-susceptible. Moxifloxacin was the most active agent amongst the drugs tested, in particular against Gram-positive pathogens. (C) 2008 Elsevier B. V. and the International Society of Chemotherapy. All rights reserved.