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

Abstract

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.

Nasopharyngeal colonization by Haemophilus influenzae in children attending day-care centers, in Ribeirão Preto, State of São Paulo, Brazil

“…In a recent report on worldwide prevalence of antimicrobial resistance, Hi resistance to TMP-SMX showed considerable regional variability (14.0-31.0% of isolates), highest rates being observed in Latin America (18), confirmed by the reported rates in Brazil 40.1-45.2% (8), in this work we reported 46.2% of TMP-SMX resistance matching other rates reported in Brazil (8).…”

“…Studies at DCCs in France, reported a high rate of β-lactamase positive strains (44.5-60.0%) (9,35) compared with those of the general population (15). In the present study, the rate of β-lactamase positive strains detected at DCCs (13.9%) was not different from those reported for the population (6,8).…”

“…In Brazil the combination of ampicillin and chloramphenicol is extensively applied because of its low cost and effectiveness (6); both antibiotics have been checked in two Brazilian studies on Hi antibiotic resistance, showing rates for ampicillin ranging from 10.0 to 13.8% (7,8), again agreeing with those presently reported.…”

“…In Latin America (10) and in Brazil (6,8), the prevalence of β-lactamase production is almost the same as that found in Europe, around 9.0-14.5%, and BLNAR strains have not been detected.…”

Semi-supervised remote sensing image classification methods assessment

“…18,19 Additionally, previous regional studies with community respiratory isolates causing infection detected approximately 30% intermediate resistance and 10% full resistance to penicillin. 20,21 For the present study, resistance rate was 18% (using non-invasive CLSI interpretation) and 100% (if invasive CLSI interpretation is applied), due to previous selection of isolates with higher chance of being resistant and, thus, to belonging to a clone. The purpose of the present study was not affected by isolates causing colonization or infection.…”