We report the antimicrobial susceptibility patterns of the most frequently isolated Gram-positive bacteria in the Brazilian hospitals participating in the SENTRYAntimicrobial Surveillance Program. The strains were consecutively collected (one per patient) between January 2005 and September 2008 and susceptibility tested by reference broth microdilution methods at the JMI Laboratories (North Liberty, Iowa, USA). A total of 3,907 Gram-positive cocci were analyzed. The Gram-positive organisms most frequently isolated from bloodstream infections were Staphylococcus aureus (2,218 strains; 20.2% of total), coagulase-negative staphylococci (CoNS; 812 strains [14.7%]), and Enterococcus spp. (754 strains; 5.0%). S. aureus ranked first (28.1%) and Enterococcus faecalis ranked 7th (4.5%) among cases of skin and soft tissue infections. S. aureus was also the second most frequently isolated pathogen from patients with lower respiratory tract infections (24.9% of cases) after Pseudomonas aeruginosa (30.5%). Resistance to oxacillin was observed in 31.0% of S. aureus and the vast majority of oxacillin-resistant (MRSA) strains were also resistant to clindamycin, ciprofloxacin and levofloxacin. Vancomycin, linezolid and daptomycin were all very active against S. aureus strains tested (>99.9-100.0% susceptible), but daptomycin (MIC50, 0.25 g/mL and MIC90, 0.5 g/mL) was four- to eight-fold more potent than vancomycin (MIC50 and MIC90 of 1 g/mL) and linezolid (MIC50, 1 g/mL and MIC90, 2 g/mL). Vancomycin resistance increased significantly among enterococci during the study period, but it was restrict to only one medical center until 2007 and emerged in a second medical center in 2008. Daptomycin was the most active antimicrobial tested against enterococci in general (100.0% susceptible), followed by linezolid (99.9% susceptible), ampicillin (87.4%) and vancomycin (84.6%). In conclusion, daptomycin and linezolid showed excellent in vitro activity against contemporary Gram-positive organisms (3,907) collected in Brazilian hospitals monitored by the SENTRY Program, including MRSA, vancomycin-resistant enterococci (VRE) and other multidrugresistant organisms. Although vancomycin resistance rates in Brazil appears to be relatively low compared to those reported in the USA, VRE has emerged and rapidly disseminated in some Brazilian medical centers.

Introdução: Pneumonia hospitalar é a mais fatal das infecções hospitalares, com taxas de mortalidade de 30 a 60%. Estima-se que 15% de todas as mortes associadas à hospitalização estejam diretamente relacionadas a pneumonias hospitalares. O SENTRY é um estudo de vigilância de resistência a antimicrobianos envolvendo centros médicos em todo o mundo. Objetivo: Avaliar a sensibilidade a antimicrobianos de bactérias isoladas no trato respiratório baixo de pacientes com pneumonia internados em hospitais brasileiros. Material e métodos: Foram avaliadas 525 amostras bacterianas de 11 hospitais brasileiros, como parte do programa SENTRY. Os isolados foram testados por microdiluição em caldo contra um grande número de antimicrobianos. Resultados: As cinco espécies mais freqüentes foram (n/%): Pseudomonas aeruginosa (158/30,1%), Staphylococcus aureus (103/19,6%), Acinetobacter spp. (68/13,0%), Klebsiella spp. (50/9,5%), e Enterobacter spp. (44/8,4%). Essas cinco espécies representam mais de 80% de toda a amostragem. A P. aeruginosa apresentou altas taxas de resistência à maioria dos antimicrobianos testados. As maiores taxas de sensibilidade foram apresentadas por piperacilina/tazobactam (71,5%) e meropenem (69,0%). Os compostos com maior atividade in vitro contra Acinetobacter spp. foram imipenem e meropenem (80,9% de sensibilidade) seguido pela tetraciclina (63,2%). A sensibilidade das amostras de Klebsiella spp. foi muito baixa. MICs > ou = 2mig/mL para ceftriaxona ou ceftazidima, indicando produção de ESBL, foram encontrados em 36,0% das amostras. Os antimicrobianos mais ativos contra Klebsiella spp. foram os carbapenens (100% de sensibilidade) e as quinolonas (92,0% de sensibilidade). Ceftriaxona foi ativa contra somente 56,8% das amostras de Enterobacter spp. (MIC50, 1mig/mL), enquanto a cefepima foi ativa contra 88,6% destes isolados (MIC50, <= 0,12mig/mL). A resistência à oxacilina foi detectada em 43,7% dos isolados de S. aureus. As drogas mais ativas contra essa espécie foram: vancomicina, teicoplanina, quinupristin-dalfopristin e linezolida. Conclusões: Os resultados do presente estudo mostraram alta prevalência de Acinetobacter spp. e altas taxas de resistência entre bacilos gram-negativos quando comparados com resultados de estudos norte-americanos e europeus.

Background: Nosocomial pneumonia is the most common fatal nosocomial infection with attributable mortality rates ranging from 30 to 60% and a rapid initiation of optimal antimicrobial therapy is important to obtain treatment success. SENTRY is a comprehensive antimicrobial surveillance study involving a great number of medical centers distributed worldwide. Objective: To evaluate the antimicrobial susceptibility of bacterial isolates collected from the lower respiratory tract of inpatients with pneumonia. Material & methods: The authors report the antimicrobial susceptibility of 525 isolates collected in 11 Brazilian hospitals, as part of the SENTRY program. The isolates were tested for susceptibility by broth micro-dilution against a large number of drugs. Results: The five most frequently isolated species were (n/%): Pseudomonas aeruginosa (158/30.1%), Staphylococcus aureus (103/19.6%), Acinetobacter spp. (68/13.0%), Klebsiella spp. (50/9.5%), and Enterobacter spp. (44/8.4%). These five species represented more than 80% of all isolates. P. aeruginosa demonstrated high rates of resistance to most antimicrobial agents tested. The highest susceptibility rates were shown by piperacillin/tazobactam (71.5%) and meropenem (69.0%). Acinetobacter spp. also showed very high rates of resistance. The most active compounds against this species were imipenem and meropenem (80.9% susceptibility) followed by tetracycline (63.2% susceptibility). Cephalosporin susceptibilities among Klebsiella spp were very low and 36.0% of isolates were considered ESBL producers based on increased MICs, > 2 mug/mL) to ceftriaxone or ceftazidime or aztreonam. Ceftriaxone was active against only 56.8% of Enterobacter spp. isolates (MIC50 1 mug/mL), while cefepime was active against 88.6% of these isolates (MIC, < 0.12 mg/mL). Oxacillin-resistance was detected in 43.7% of S. aureus isolates. The most active drugs against this species were vancomycin, teicoplanin, quinupristin/dalfopristin, and linezolid. Conclusion: The results of this study demonstrated a higher prevalence of Acinetobacter spp. and higher resistance rates among Gram-negative rods when compared with results from North American and European studies.

O tratamento da pneumonia adquirida na comunidade (PAC) é habitualmente empírico e o uso de antimicrobianos é baseado em estudos de vigilância. O programa SENTRY foi desenhado para monitorar a resistência a antimicrobianos através de uma rede internacional de laboratórios. Três centros no Brasil participaram do Programa SENTRY em 1997 e em 1998. Métodos: Um total de 344 isolados bacterianos coletados de pacientes com PAC em 1997 e 1998 foram testados contra mais de 20 agentes antimicrobianos pelo método de microdiluição em caldo. Resultados: Entre os S. pneumoniae (176 isolados), 71,6% foram sensíveis à penicilina. Alto nível de resistência à penicilina e resistência à cefotaxima foram encontrados em 2,3 e 4,0%, respectivamente. As novas quinolonas levofloxacina (MIC90, 2mig/mL) e gatifloxacina (MIC90, 0,5mig/mL) foram ativas contra 100% dos isolados testados. Entre os outros antimicrobianos não beta-lactâmicos testados, os mais ativos foram (% de sensibilidade): cloranfenicol (97,5%) > clindamicina (94%) > azitromicina (90,3%) > claritromicina (89,4%) > tetraciclina (76,4%) > sulfametoxazol/trimetoprim (60,2%). A percentagem de Haemophilus influenzae (101 isolados) resistentes à amoxicilina foi de 90,1%, enquanto entre Moraxella catarrhalis (67 isolados) somente 9,0% foram sensíveis. O ácido clavulânico restaurou a atividade de amoxicilina contra H. influenzae e M. catarrhalis. Porém, H. influenzae demonstrou níveis aumentados de resistência para sulfametoxazol/trimetoprim (55,1% de sensibilidade), claritromicina (80,4% de sensibilidade) e cefaclor (88,2% de sensibilidade). Todos os isolados de H. influenzae e M. catarrhalis foram sensíveis à levofloxacina (MIC90, <= 0,5mig/mL para ambos) e gatifloxacina (MIC90, <= 0,06mig/mL para ambos) apresentando MICs muito baixos. Conclusões: Os resultados indicam que a prevalência de S. pneumoniae com alto grau de resistência à penicilina é ainda baixa no Brasil; porém, a prevalência de S. pneumoniae com resistência intermediária à penicilina e resistência cruzada a outras classes de antimicrobianos é relativamente alta em nosso meio. Por outro lado, as novas quinolonas são altamente ativas contra S. pneumoniae e outros patógenos responsáveis por infecções respiratórias adquiridas na comunidade.

Background: Antimicrobial treatment of community-acquired respiratory tract infections (CARTI) is usually empiric and antibiotics are chosen on the basis of surveillance studies. The SENTRY Program was designed to monitor antimicrobial resistance via a worldwide surveillance network of sentinel laboratories. Three sites in Brazil participated in the 1997 and 1998 SENTRY Program. Methods: A total of 344 bacterial isolates, collected from patients with CARTI in 1997 and 1998, were tested against more than 20 antimicrobial agents by the broth microdilution method. Results: Among S. pneumoniae (176 isolates), 71.6% were susceptible to penicillin. High level resistance to penicillin and resistance to cefotaxime was found in 2.3 and 4.0%, respectively. The newer quinolones, levofloxacin, (MIC90 of 2 mug/mL) and gatifloxacin (MIC90 of 0.5 mug/mL) were active against 100% of the isolates tested. Among the other non-beta-lactam drugs tested, the rank order of pneumococci activity was (% susceptible): chloramphenicol (97.5%) > clindamycin (94.0%) > azithromycin (90.3%) > clarithromycin (89.4%) > tetracycline (76.4%) > trimethoprim/sulfamethoxazole (60.2%). The percentage of Haemophilus influenzae (101 isolates) susceptible to amoxicillin was 90.1%, whereas among Moraxella catarrhalis (67 isolates) only 9.0% were susceptible. Clavulanic acid restored the activity of amoxicillin against both H. influenzae and M. catarrhalis. However, H. influenzae showed increased levels of resistance to trimethoprim/sulfametoxazole (55.1% susceptibility), clarithromycin (80.4% susceptibility), and cefaclor (88.2%) susceptibility). All H. influenzae and M. catarrhalis isolates were susceptible to levofloxacin (MIC90, < 0.5 mug/mL for both) and gatifloxacin (MIC90, < 0.06 mug/mL for both) with very low MICs. Conclusion: Results indicate that the rate of S. pneumoniae showing high-level penicillin resistance is still low in Brazil. However, intermediate resistance to penicillin associated with resistance to other classes of antimicrobial agents was relatively high. On the other hand, the new quinolones were highly active against 100% of the respiratory pathogens tested.