Antibiotic resistance and trend of urinary pathogens in general outpatients from a major urban city

OBJECTIVE: We assessed the antimicrobial resistance patterns of pathogens responsible for urinary tract infections (UTI) in outpatients in São Paulo, Brazil, as well as the Escherichia coli antimicrobial resistance trend. MATERIALS AND METHODS: Outpatients urine cultures were collected from January 2000 to December 2003. Statistical analysis considered positive results for one bacterial species with colony count > 100,000 CFU/mL. Stratification was done on age group and gender. Statistical tests used included chi-square and the chi-square test for trend to evaluate differences between susceptibility rates among age groups and ordering in the E. coli resistance rates per year, respectively. RESULTS: There were 37,261 positive results with Enterobacteriaceae isolated in 32,530 (87.3 percent) and Gram-positive cocci in 2,570 (6.9 percent) cultures. E. coli had the highest prevalence (71.6 percent). Susceptibility tests were performed in 31,716 cultures. E. coli had elevated resistance rates (> 30 percent) to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline. Significant differences between age groups and ordering among years were observed. CONCLUSIONS: The use of trimethoprim-sulfamethoxazole is precluded in the population studied due to elevated resistance rates (> 30 percent) among most prevalent pathogens. Significant resistance rate differences among age groups and years were observed, particularly for fluoroquinolones. Fluoroquinolones should be used with caution. Nitrofurantoin should be used as empirical therapy for primary, non-complicated urinary tract infections.

Results of the 1997 SENTRY Antimicrobial Surveillance Program in three Brazilian medical centers

The SENTRY Antimicrobial Surveillance Program began in January, 1997, and is designed to monitor nosocomial and selected community acquired infections via a worldwide surveillance network of sentinel hospitals distributed equally by geographic location and size. Three sites in Brazil - Rio de Janeiro, Florianópolis, and Säo Paulo - participated in the SENTRY Antimicrobial Surveillance Program stet. Rank order of occurrence and antimicrobial susceptibillity of pathogenic species causing bloodstream infections, pneumonia, wound or skin and soft tissue infections, and urinary tract infections (UTI) in hospitalized patients were determined by collecting consecutive isolates over a specified period of time. Antimicrobial susceptibilities of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis obtained from outpatients with respiratory tract infections were also evaluated. The isolates for the evaluated infections were: 1) bloodstream - 20 consecutive isolates in each calendar month during a 12-month period; 2) pneumonia - 100 consecutive isolates over a 6 month period; 3) wound or skin and soft tissue - 50 consecutive isolates over a 3 month period; and 4) UTI - 50 consecutive isolates over a 3 month period. Each hospital also contributed, over a 6 month period, consecutive clinically significant outpatient isolates (one isolate per patient) of S. pneumoniae, H. influenzae, and M. catarrhalis that were considered pathogens in respiratory tract infections. Data collected for each isolate included species identification, antimicrobial susceptibility profile, data of isolation, and specimen type. Molecular studies were performed on selected isolates. A total of 1,241 bacterial strains were obtained; the majority were cultured from hospitalized patients, while 139 were fastidious organisms from community acquired respiratory tract infections. Gram-negative bacilli and S. aureus were the predominant pathogens, and Enterobacter spp. was a significant pathogen. The predominance of P. aeruginosa and Acinetobacter spp. and the significant levels of resistence to most agents are of major concern, as is the epidemic rate of ESBL-producing strains of Klebsiella spp. and E. coli in Brazil, which is much higher than rates seen in other areas of the world. Resistance among P. aeruginosa and the Enterobacteriaceae to fluoroquinolones, oxacillin-resistant S. aureus, and penicillin- and trimethoprim-sulfamethoxazole-resistant pneumococci were other...