A total of 2484 target bacterial pathogens were collected (one per patient episode) from patients in 16 Latin American medical centers located in seven nations during 2011. Isolate identity was confirmed at a coordinating laboratory and susceptibility testing was performed for ceftaroline and comparator agents according to reference broth microdilution methods. A total of 30.0% of isolates were from respiratory tract, 29.4% from skin and skin structure, 21.4% from blood stream, 7.9% from urinary tract and 11.3% from other sites. Ceftaroline was active againstStaphylococcus aureus (42.8% MRSA) with 83.6% of the isolates at <1mg/L and all isolates at <2mg/L (MIC5090, 0.25/2mg/L). National MRSA rates ranged from a low of 28.8% in Colombia to a high of 68.1% in Chile. All Streptococcus pyogenes and Streptococcus agalactiae were susceptible to ceftaroline (MIC50/90 values were at <0.015/<0.015mg/L for both). All Streptococcus pneumoniae were susceptible to ceftaroline, linezolid, tigecycline and vancomycin. Susceptibility to ceftriaxone was at 88.4% (CLSI non-meningitis interpretive criteria) and 73.9% (CLSI meningitis interpretive criteria) for all S. pneumoniae. Ceftriaxone susceptibility was only at 33.3% (CLSI non-meningitis interpretive criteria) and 0.0% (CLSI meningitis interpretive criteria) for penicillin-intermediate (penicillin MIC, 4mg/L) strains. AllHaemophilus influenzae (29.4% β-lactamase-positive) isolates were susceptible to ceftaroline, amoxicillin-clavulanate, ceftriaxone, and levofloxacin. For the Latin American region, the ESBL-phenotype rate was 37.6% for Escherichia coliand 53.3% for Klebsiella pneumoniae. Ceftaroline was not active against ESBL-phenotype strains but was active against >90.0% of the non-ESBL-phenotype. The spectrum of activity of ceftaroline against pathogens from Latin America indicates that it merits further study for its potential use in the Latin American region.

OBJECTIVE: To establish a resistance (R) surveillance program monitoring antimicrobial susceptibility patterns in Latin America (LATAM; Argentina [ARG], Brazil [BRA], Chile, Colombia [CBA], Costa Rica, Ecuador [ECU], Guatemala [GUA], Mexico [MEX], Panama [PAN], Peru, and Venezuela [VEN]). METHODS: In 2011, 4979 organisms were collected from 11 nations (20 laboratories) for susceptibility testing in a central laboratory design. Antimicrobials were tested by CLSI methods and results interpreted by CLSI and EUCAST breakpoints. Most common Gram-positive (Staphylococcus aureus [SA, 921], other staphylococci [CoNS; 299], enterococci [218], Streptococcus pneumoniae [SPN; 182], β-haemolytic streptococci [115]) and Gram-negative (E. coli [EC; 644], Klebsiella spp. [KSP; 517], Enterobacters [272], Pseudomonas aeruginosa [PSA; 586], Acinetobacters [ACB; 494]) pathogens were analyzed against linezolid (LZD), vancomycin (VAN), tigecycline (TIG), colistin (COL), cefoperazone/sulbactam (C/S), and amikacin (AMK). RESULTS: MRSA rates varied from 29% (CBA, BRA) to 79% (Peru); but LZD (MIC90, 2 mg/L), TIG (MIC90, 0.12mg/L) and VAN (MIC90, 1mg/L) covered all strains. Enterococci showed a 14% VRE rate, highest in BRA and MEX; all inhibited by TIG and daptomycin, but not LZD (three non-susceptible with G2576T mutations or cfr). Penicillin-R among SPN and viridans streptococci was 51.6 and 41.1%, respectively. LZD overall R against Gram-positives was 0.3%. High ESBL rates were observed in EC (54-71%) and KSP (>50%) from GUA, MEX and Peru, and six nations, respectively. Carbapenem-R in KSP was 9%, highest rates associated with KPC in BRA, CBA, ECU, PAN and VEN; also a NDM-1 in KSP from CBA. AMK, TIG, C/S and carbapenems were the broadest-spectrum agents tested against Enterobacteriaceae. Only COL inhibited >90% of PSA; COL and TIG (<2 mg/L) covered >85% of ACB. CONCLUSIONS: LATAM nations demonstrated variable levels of antimicrobial R especially among Enterobacteriaceae (β-lactamase-mediated), PSA and ACB. MRSA (48%), VRE (14%) and multidrug-R SPN were also regional therapeutic challenges.

Ceftaroline, the active metabolite of the prodrug ceftaroline fosamil, is a cephalosporin with in vitro bactericidal activity against Gram-positive organisms, including methicillinsusceptible and -resistant Staphylococcus aureus, β-haemolytic and viridans group streptococci, and Streptococcus pneumoniae, as well as common Gram-negative organisms. In this study a total of 986 isolates collected in 2010 from patients in 15 medical centers in five Latin American countries from the Assessing Worldwide Antimicrobial Resistance Evaluation Program were identified as community-acquired respiratory tract or skin and soft tissue infection pathogens. Ceftaroline was the most potent agent tested against S. pneumoniae with a MIC90 value (0.12 µg/mL) that was eight-fold lower than ceftriaxone, levofloxacin, and linezolid. Its spectrum of coverage (100.0% susceptible) was similar to tigecycline, linezolid, levofloxacin and vancomycin. Against Haemophilus influenzae and Moraxella catarrhalis, ceftaroline was the most active agent tested. The activity of ceftaroline against S. aureus (including MRSA) was similar to that of vancomycin and tetracycline (MIC90,1 µg/mL) and linezolid (MIC90,2 Jg/mL). The 1-haemolytic streptococci exhibited 100.0% susceptibility to ceftaroline. Ceftaroline activity against Escherichia coli, Klebsiella spp., and Enterobacter spp. was similar to that of ceftriaxone and ceftazidime. These parenteral cephalosporin agents have potent activity against non-extended-spectrum These parenteral cephalosporin agents have potent activity against non-extended-spectrum-lactamase-phenotype strains, but are not active against extended-spectrum β-lactamase-phenotype strains. These results confirm the in vitro activity of ceftaroline against pathogens common in communityacquired respiratory tract and skin and soft tissue infection in Latin America, and suggest that ceftaroline fosamil could be an important therapeutic option for these infections.

Emerging resistance phenotypes and antimicrobial resistance rates among pathogens recovered from community-acquired urinary tract infections (CA-UTI) is an increasing problem in specific regions, limiting therapeutic options. As part of the SENTRY Antimicrobial Surveillance Program, a total of 611 isolates were collected in 2003 from patients with CA-UTI presenting at Latin American medical centers. Each strain was tested in a central laboratory using Clinical Laboratory Standard Institute (CLSI) broth microdilution methods with appropriate controls. Escherichia coli was the leading pathogen (66%), followed by Klebsiella spp. (7%), Proteus mirabilis (6.4%), Enterococcus spp. (5.6%), and Pseudomonas aeruginosa (4.6%). Surprisingly high resistance rates were recorded for E. coli against first-line orally administered agents for CA-UTI, such as ampicillin (53.6%), TMP/SMX (40.4%), ciprofloxacin (21.6%), and gatifloxacin (17.1%). Decreased susceptibility rates to TMP/SMX and ciprofloxacin were also documented for Klebsiella spp. (79.1 and 81.4%, respectively), and P. mirabilis (71.8 and 84.6%, respectively). For Enterococcus spp., susceptibility rates to ampicillin, chloramphenicol, ciprofloxacin, and vancomycin were 88.2, 85.3, 55.9, and 97.1%, respectively. High-level resistance to gentamicin was detected in 24% of Enterococcus spp. Bacteria isolated from patients with CA-UTI in Latin America showed limited susceptibility to orally administered antimicrobials, especially for TMP/SMX and fluoroquinolones. Our results highlight the need for developing specific CA-UTI guidelines in geographic regions where elevated resistance to new and old compounds may influence prescribing decisions.

The in vitro activity of tigecycline (former GAR-936), a new semisynthetic tetracycline, was evaluated in comparison with tetracycline and other antimicrobial agents. MATERIAL AND METHODS: A total of 1,326 contemporary clinical isolates collected from the Latin American region were collected in 2000-2002 period and tested with microdilution broth according to the CLSI guidelines. The bacterial pathogens evaluated included Staphylococcus aureus (505), Streptococcus pneumoniae (269), coagulase-negative staphylococci (CoNS; 227), Haemophilus influenzae (129), Enterococcus spp. (80), Moraxella catarrhalis (54), beta-haemolytic streptococci (28), viridans group streptococci (26), and Neisseria meningitidis (8) RESULTS:Tigecycline demonstrated excellent activity against all Gram-positive cocci, with 90% of penicillin-resistant S. pneumoniae strains being inhibited at 0.12 µg/mL, while the same isolates had an MIC90 of > 16 µg/mL for tetracycline. All Enterococcus spp. were inhibited at 0.25 µg/mL of tigecycline. Tigecycline (MIC50, 0.25 µg/mL) was eight-fold more potent than minocycline (MIC50, 2 µg/mL) against oxacillin-resistant S. aureus (ORSA); all ORSA were inhibited at < 2 µg/mL of tigecycline. Tigecycline demonstrated excellent activity (MIC50, 0.5 µg/mL) against CoNS with reduced susceptibility to teicoplanin (MIC, 16 µg/mL). Tigecycline also showed high potency against respiratory pathogens such as M. catarrhalis (MIC50, 0.12 µg/mL) and H. influenzae (MIC50, 0.5 µg/mL). No tigecycline resistant isolates were detected when the proposed susceptible breakpoints (< 4 µg/mL) was applied. CONCLUSIONS: This results indicate that tigecycline has potent in vitro activity against clinically important pathogenic bacteria, including Gram-positive isolates resistant to both tetracycline and minocycline.

The antimicrobial susceptibility of 176 unusual non-fermentative gram-negative bacilli (NF-GNB) collected from Latin America region through the SENTRY Program between 1997 and 2002 was evaluated by broth microdilution according to the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. Nearly 74% of the NF-BGN belonged to the following genera/species: Burkholderia spp. (83), Achromobacter spp. (25), Ralstonia pickettii (16), Alcaligenes spp. (12), and Cryseobacterium spp. (12). Generally, trimethoprim/sulfamethoxazole (MIC50, < 0.5 µg/ml) was the most potent drug followed by levofloxacin (MIC50, 0.5 µg/ml), and gatifloxacin (MIC50, 1 µg/ml). The highest susceptibility rates were observed for levofloxacin (78.3%), gatifloxacin (75.6%), and meropenem (72.6%). Ceftazidime (MIC50, 4 µg/ml; 83.1% susceptible) was the most active beta-lactam against B. cepacia. Against Achromobacter spp. isolates, meropenem (MIC50, 0.25 µg/ml; 88% susceptible) was more active than imipenem (MIC50, 2 µg/ml). Cefepime (MIC50, 2 µg/ml; 81.3% susceptible), and imipenem (MIC50, 2 µg/ml; 81.3% susceptible) were more active than ceftazidime (MIC50, >16 µg/ml; 18.8% susceptible) and meropenem (MIC50, 8 µg/ml; 50% susceptible) against Ralstonia pickettii. Since selection of the most appropriate antimicrobial agents for testing and reporting has not been established by the NCCLS for many of NF-GNB species, results from large multicenter studies may help to guide the best empiric therapy.

The alarming emergence and spread of antimicrobial resistance among common bacteria threatens the effectiveness of therapy for many infections. Surveillance of antimicrobial resistance is essential to identify the major problems and guide adequate control measures. Several resistance surveillance programs have been implemented in North America and Europe in the last decade; however, very few programs have assessed antimicrobial resistance in Latin American countries. The SENTRY Antimicrobial Surveillance Program was initiated in 1997 and represents the most comprehensive surveillance program in place at the present time worldwide. The SENTRY Program collects consecutive isolates from clinically documented infections in more than 80 medical centers worldwide (10 in Latin America). The isolates are collected according to the type of infection (objectives) and susceptibility tested in a central microbiology laboratory by reference broth microdilution methods according to NCCLS guidelines. The Program also incorporated molecular typing (ribotyping and PFGE) and resistance mechanism analysis of selected isolates. In this report we present a very broad analysis of the data generated by testing almost 20,000 bacterial isolates against more than 30 antimicrobial agents. The susceptibility results (MIC50, MIC90 and % susceptible) are presented in 11 tables according to the organism and site of infection. The data from Brazil, as well as the data from isolates collected in 2001, are analyzed separately. This report allows the evaluation of the activities numerous antimicrobial agents against clinical isolates collected in Latin American countries.

The accuracy of antimicrobial susceptibility tests is a crucial step for the clinical management of patients with serious infections. They must be reliable and precise because they will guide antimicrobial therapy. Our main objective was to compare the results of susceptibility testing performed by the SENTRY coordinator laboratory with those reported by the participating Latin American medical centers. A total of 10,277 bacterial isolates were tested by the reference broth microdilution method at the coordinator laboratory in the United States. The tests were performed and interpreted following the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. Ten antimicrobial agent-organism combinations were analyzed. The susceptibility methods utilized in each of the medical centers were also evaluated. Total agreement of the results was obtained in nearly 88% of the antimicrobial agent-organism combinations. "Very major" (false-susceptible results) and "major errors" (false-resistant results) were observed in 12% and 6% of the cases, respectively. The highest disagreements were observed for coagulase-negative Staphylococcus - oxacillin (20% - very major error) and Burkholderia cepacia - imipenem (21% - very major error). The susceptibility method with the highest agreement rate was Etest® (92%) > PASCO® (91%) > agar dilution (91%) > MicroScan® (90%) > Vitek® (87%). External quality assurance data obtained by surveillance programs such as the SENTRY Antimicrobial Surveillance Program are not only helpful for detecting the emergence of patterns of antimicrobial resistance, but also to monitor the performance of the participating microbiology laboratories.

Linezolid was the first clinically applied member of the new antimicrobial class called the "oxazolidinones". These agents have a powerful spectrum of activity focussed against Gram-positive organisms including strains with documented resistances to other antimicrobial classes. We conducted a multicenter surveillance (Zyvox Antimicrobial Potency Study; ZAPS) trial of qualifying Gram-positive isolates from 24 medical centers in eight countries in Latin America. The activity and spectrum of linezolid was compared to numerous agents including glycopeptides, quinupristin/dalfopristin, b-lactams and fluoroquinolones when testing 2,640 strains by the standardized disk diffusion method or Etest (AB BIODISK, Solna, Sweden). The linezolid spectrum was complete against staphylococci (median zone diameter, 29 - 32 mm), as was the spectrum of vancomycin and quinupristin/dalfopristin. Among the enterococci, no linezolid resistance was detected, and the susceptibility rate was 93.1 - 96.4%. Only the vancomycin-susceptible Enterococcus faecium strains remained susceptible (92.8%) to quinupristin/dalfopristin. Marked differences in the glycopeptide resistance patterns (van A versus van B) were noted for the 22 isolates of VRE, thus requiring local susceptibility testing to direct therapy. Streptococcus pneumoniae and other species were very susceptible (100.0%) to linezolid, MIC90 at 0.75 mug/ml. Penicillin non-susceptible rate was 27.7% and erythromycin resistance was at 17.4%. Other streptococci were also completely susceptible to linezolid (MIC90, 1 mug/ml). These results provide the initial benchmark of potency and spectrum for linezolid in Latin American medical centers. Future comparisons should recognize that the oxazolidinones possess essentially a complete spectrum coverage of the monitored staphylococci, enterococci and streptococcal isolates in 2000-2001. This positions linezolid as the widest spectrum empiric choice against multi-resistant Gram-positive cocci, a spectrum of activity greater than available glycopeptides and the streptogramin combination.

BACKGROUND: Pathogen frequency and resistance patterns may vary significantly from country to country and also in different hospitals within a country. Thus, regional surveillance programs are essential to guide empirical therapy and infection control measures. METHODS: Rank order of occurrence and antimicrobial susceptibility of pathogenic species causing bloodstream infections (BSI), lower respiratory tract infections (LRTI), wound or skin and soft tissue infections (WSSTI), and urinary tract infections (UTI) in hospitalized patients were determined by collecting consecutive isolates over a specified period of time, as part of the SENTRY Antimicrobial Resistance Surveillance Program (SENTRY). All isolates were tested by reference broth microdilution. RESULTS AND CONCLUSIONS: A total of 3,728 bacterial strains were obtained from January, 1997, to December, 1999, from 12 Brazilian hospitals located in 4 states. The largest number of isolates were obtained from patients with BSI (2,008), followed by LRTI (822 cases), UTI (468 cases), and WSSTI (430 cases). Staphylococcus aureus was the most frequently isolated pathogen in general (22.8% - 852 isolates), followed by E. coli (13.8% - 516 cases) and Pseudomonas aeruginosa (13.3% - 496 cases). Staphylococcus aureus was also the most common species isolated from BSI (23.6%) and WSSTI (45.8%), and P. aeruginosa was the most frequent species isolated from patients with LRTI (29.4%). The main bacterial resistance problems found in this study were: imipenem resistance among P. aeruginosa (69.8% susceptibility) and Acinetobacter spp. (88.1% susceptibility); ESBL production among K. pneumoniae (48.4%) and E. coli (8.9%); resistance to third generation cephalosporins among Enterobacter spp. (68.1% susceptible to ceftazidime) and oxacillin resistance among S. aureus (34.0%) and coagulase negative staphylococci (80.1%). Only the carbapenems (88.1% to 89.3% susceptibility) showed reasonable activity against the Acinetobacter spp. isolates evaluated.

The new oxazolidinone linezolid and other antimicrobial agents used to treat Gram-positive infections were tested against 1,585 Gram-positive cocci; 1,260 staphylococci and enterococci isolates from patients hospitalized in Brazilian hospitals, and 325 S. pneumoniae isolates for patients with community acquired infections. Susceptibility testing was performed using broth microdilution according to NCCLS procedures. Linezolid was the most active compound and the only drug that inhibited 100% of the isolates at the susceptible breakpoint (< 4 mg/mL). Resistance to vancomycin was very rare (99.9% susceptibility), and both quinupristin/dalfopristin and gatifloxacin were active against approximately 90% of the strains evaluated. All other compounds inhibited less than 65% of the isolates. The excellent in vitro Gram-positive activity by linezolid, in this study, indicate that this compound may represent an important therapeutic option for the treatment of infections caused by these pathogens in Brazil.

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.

We report for the first time in Brazil, a patient from whom an Enterococcus faecalis VanA phenotype was isolated. Glycopeptide resistance is not commonly observed in Enterococcus faecalis, so this finding is of great concern since this species is responsible for 90% of enterococcal infections in Brazil. The isolate was recovered from a surveillance rectal swab culture from a patient with acute lymphocytic leukemia (ALL). Identification to the species level was performed by conventional biochemical tests and Vitek GPI cards. Antimicrobial susceptibility testing was evaluated by use of broth microdilution and Etest (AB BIODISK, Solna, Sweden) methods. The isolate was identified as E. faecalis and was considered resistant to both vancomycin (MIC, > 256 mug/mL) and teicoplanin (MIC, 256 mug/mL). The isolate also showed high level resistance to gentamicin and streptomycin (MICs, > 1024 mug/mL), but was considered susceptible to ampicillin (MIC, 4 mug/mL). Although the frequency of enterococcal infections is very low in most Latin America countries, the finding of glycopeptide (VanA) resistance in E. faecalis increases concern about apreading antimicrobial resistance in this region.

Gram-positive cocci are important causes of both nosocomial and community-acquired infections, and antimicrobial resistance among these pathogens has become an important problem worldwide. Since resistance among these organisms can vary substantially by geographic location, we conducted a multicenter surveillance study with isolates from five Latin American countries (15 medical centers). Quinupristin/dalfopristin (formerly RP-59500) is a novel streptogramin combination with focused activity against Gram-positive cocci, many exhibiting emerging resistance. The in vitro activity of quinupristin/dalfopristin and 12 other antimicrobial agents were evaluated against 1,948 strains including Staphylococcus aureus (747 strains), coagulase-negative staphylococci (CoNS; 446 strains), enterococci (429 strains), and various Streptococcus spp. (326 strains). Oxacillin resistance was observed in 41% of S. aureus (MIC, <= 2 mug/ml or > or = 13 mm) and 40% of CoNS (MIC, <= 0.25 mug/ml or > or = 18 mm). Vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC90, 0.25 - 1 mug/ml) remained effective against all strains, but cross-resistance was high among other tested drugs. The quinupristin/dalfopristin MIC50 for Streptococcus pneumoniae and other streptococci was only 0.5 mug/ml (13% to 28% were penicillin-resistant; 12% to 22% were macrolide-resistant). Enterococci demonstrated variable inhibition by quinupristin/dalfopristin depending upon identification and the susceptibility testing method used. The demonstrated quinupristin/dalfopristin activity against Enterococcus faecium was confirmed, but potential species identification errors with various commercial systems continue to confuse susceptibility statistics, even though some strains of E. faecium confirmed by PCR-based or other molecular identification techniques did have quinupristin/dalfopristin MICs of > or = 4 mug/mL. Most important, glycopeptide-resistant enterococci are rapidly emerging in Latin America, and quinupristin/dalfopristin appears active against many of these isolates as well as having potency against nearly all staphylococci and streptococci tested at <= 2 mug/ml or having a zone diameter of > or = 16 mm. Comparisons to GSMART results from other continents show nearly identical quinupristin/dalfopristin activity for each Gram-positive species tested. These results define the role of quinupristin/dalfopristin in Latin American medical centers and provide a benchmark for future in vitro comparisons.

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.