The activity of levofloxacin and comparator agents against clinical isolates of Streptococcus pneumoniae collected worldwide during 1999 and 2000.

BACKGROUND: Increases in penicillin-resistant Streptococcus pneumoniae have been documented worldwide. METHODS: During 1999 and 2000, 5,015 S. pneumoniae isolates were collected from 13 countries on five continents and tested for antimicrobial susceptibility. RESULTS: Penicillin resistance rates were as follows: South Korea, 70.1%; Hong Kong, 50.3%; Thailand, 39.3%; France, 28.7%; Spain, 24.8%; Mexico, 18.1%; Ireland, 11.8%; South Africa, 11.1%; Italy, 9.4%; United Kingdom, 3.1%; Brazil, 2.9%; China, 2.3%, and Germany, 0.7%. Resistance to azithromycin, clarithromycin and trimethoprim-sulfamethoxazole was commonly associated with penicillin resistance. Levofloxacin-resistant isolates were detected in 8 of 13 countries: Germany (0.2%), France (0.4%), Thailand (0.5%), South Korea (0.9%), Mexico (1.5%), Spain (1.6%), China (3.3%) and Hong Kong (8.0%). Multidrug resistance (resistance to >/=3 antimicrobial classes) occurred in 626/5,015 isolates (12.5%). Levofloxacin was active against 96.0% (601/626) of the multidrug-resistant (MDR) isolates and 99.7% (4,374/4,389) of the non-MDR isolates. CONCLUSION: Although relatively high levels of levofloxacin resistance were detected in China and Hong Kong, overall, levofloxacin remained active against >99% of clinical isolates of S. pneumoniae despite their resistance to other agents. Continued surveillance of S. pneumoniae will track any changes in levofloxacin activity, should they occur.

Antimicrobial resistance in respiratory pathogens isolated in Brazil during 1999-2000

The in vitro antimicrobial susceptibility of the respiratory pathogens Streptococcus Pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis to commonly tested and prescribed agents was investigated during 1999-2000 and compared with results obtained during a previous 1997-1998 study. Of 448 isolates of S. Pneumoniae collected and tested in 1999-2000, 77.2 were susceptible, 19.9 were intermediate, and 2.9 were resistant to penicillin, demonstrating that there were no major changes in susceptibility to penicillin from 1997-1998 (77.1 susceptible, 18.7 intermediate, 4.2 resistant). All S. Pneumoniae isolates from 1999-2000 were susceptible to levofloxacin and vancomycin and >90 were susceptible to the B-lactams (amoxicillin-clavulanate, ceftriaxone, and cefuroxime) and macrolides (axithyromycin and clarithromycin), showing that susceptibility to these agents also remained unchanged since 1997-1998. The most notable increase in resistance between the two studies was demonstrated by trimethoprim-sulfamethoxazole, which increased from 23.4 to 38.6. Penicillin resistance correlated with resistance to B-lactams, macrolides, and trimethoprim-sulfamethoxazole in both studies. In H. influenzae, the prevalence of B-lactamase-producing isolates remained unchanged (10.6 in 1999-2000; 11.0 in 1997-1998). All H. influenzae isolates were susceptible to levofloxacine, ceftriaxone, cefuroxime, and azithromycin, and showed no change between the two studies. Trimethoprim-sulfamethoxazole resistance was present in 40.1 of isolates in 1999-2000, and in 45.2 in 1997-1998. In M. catarrhalis, the prevalence of B-lactamase-producing isolates was unchanged (97.9 in 1999-2000;98.0 in 1997-1998). The most active agents against M. catarrhalis were azithromycin (MIC(90),< or = 0.03 microg/ml) and levofloxacin (MIC(90),< or = 0.03 microg/ml). Overall, these results suggest that, in Brazil, between 1999-2000 and 1997-1998, there have been no significant changes in the susceptibility of respiratory pathogens to any of the commonly tested and prescribed agents with the exception of trimethoprim-sulfamethoxazole for S. Pneumoniae.