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.
Critchley
I A
IA
Focus Technologies, Inc., Herndon, Virginia, 20171-4603, USA. icritchley@mrlinfo.com
Blosser
R S
RS
Karlowsky
J A
JA
Yamakita
J
J
Barth
A
A
Sader
H S
HS
Mendes
C
C
Teixeira
L
L
Rossi
F
F
Dias
C A
CA
Jones
M E
ME
Thornsberry
C
C
Sahm
D F
DF
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001938:Brazil / Q000453:epidemiology; D024881:Drug Resistance, Bacterial; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D008137:Longitudinal Studies; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects*; D011159:Population Surveillance; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000187:drug effects*
D000900:Anti-Bacterial Agents