Ceftaroline activity tested against contemporary Latin American bacterial pathogens (2011)

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 coli and 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.

Susceptibility rates in Latin American nations: report from a regional resistance surveillance program (2011)

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.

Spectrum and potency of ceftaroline against leading pathogens causing community-acquired respiratory tract and skin and soft tissue infections in Latin America, 2010

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.

Increased resistance to first-line agents among bacterial pathogens isolated from urinary tract infections in Latin America: time for local guidelines?

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 percent), followed by Klebsiella spp. (7 percent), Proteus mirabilis (6.4 percent), Enterococcus spp. (5.6 percent), and Pseudomonas aeruginosa (4.6 percent). Surprisingly high resistance rates were recorded for E. coli against first-line orally administered agents for CA-UTI, such as ampicillin (53.6 percent), TMP/SMX (40.4 percent), ciprofloxacin (21.6 percent), and gatifloxacin (17.1 percent). Decreased susceptibility rates to TMP/SMX and ciprofloxacin were also documented for Klebsiella spp. (79.1 and 81.4 percent, respectively), and P. mirabilis (71.8 and 84.6 percent, respectively). For Enterococcus spp., susceptibility rates to ampicillin, chloramphenicol, ciprofloxacin, and vancomycin were 88.2, 85.3, 55.9, and 97.1 percent, respectively. High-level resistance to gentamicin was detected in 24 percent 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.

Survey of bloodstream infection isolates: SENTRY Antimicrobial Surveillance Program in Buenos Aires, Argentina (1997-2002)

Regional antimicrobial surveillance programs might help to guide empiric antimicrobial therapy. This study reports the antimicrobial susceptibility patterns of 2198 isolates from bloodstream infections in a period of 1997 to 2002. Susceptibility testing was performed by broth microdilution methods. The most frequent organism was Staphylococcus aureus (23.4%) with an oxacillin-resistance rate of 41.8%. Extended Spectrum Beta Lactamases phenotype was presented in 10.0% of Escherichia coli and 49.4% in Klebsiella pneumoniae isolates. Imipenem and meropenem were active against 74.3% and 84.0% of Acinetobacter spp. and Pseudomonas aeruginosa, respectively. Bacterial resistance continues to be a great problem in Argentinean medical centers.

In vitro activity of tigecycline, a new glycylcycline, tested against 1,326 clinical bacterial strains isolated from Latin America

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 percent of penicillin-resistant S. pneumoniae strains being inhibited at 0.12 æg/mL, while the same isolates had an MIC90 of > 16 æg/mL for tetracycline. All Enterococcus spp. were inhibited at 0.25 æg/mL of tigecycline. Tigecycline (MIC50, 0.25 æg/mL) was eight-fold more potent than minocycline (MIC50, 2 æg/mL) against oxacillin-resistant S. aureus (ORSA); all ORSA were inhibited at < 2 æg/mL of tigecycline. Tigecycline demonstrated excellent activity (MIC50, 0.5 æg/mL) against CoNS with reduced susceptibility to teicoplanin (MIC, 16 æg/mL). Tigecycline also showed high potency against respiratory pathogens such as M. catarrhalis (MIC50, 0.12 æg/mL) and H. influenzae (MIC50, 0.5 æg/mL). No tigecycline resistant isolates were detected when the proposed susceptible breakpoints (< 4 æg/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.

Antimicrobial susceptibility patterns of unusual nonfermentative gram-negative bacilli isolated from Latin America: report from the SENTRY Antimicrobial Surveillance Program (1997-2002)

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 percent 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 æg/ml) was the most potent drug followed by levofloxacin (MIC50, 0.5 æg/ml), and gatifloxacin (MIC50, 1 æg/ml). The highest susceptibility rates were observed for levofloxacin (78.3 percent), gatifloxacin (75.6 percent), and meropenem (72.6 percent). Ceftazidime (MIC50, 4 æg/ml; 83.1 percent susceptible) was the most active beta-lactam against B. cepacia. Against Achromobacter spp. isolates, meropenem (MIC50, 0.25 æg/ml; 88 percent susceptible) was more active than imipenem (MIC50, 2 æg/ml). Cefepime (MIC50, 2 æg/ml; 81.3 percent susceptible), and imipenem (MIC50, 2 æg/ml; 81.3 percent susceptible) were more active than ceftazidime (MIC50, >16 æg/ml; 18.8 percent susceptible) and meropenem (MIC50, 8 æg/ml; 50 percent 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.

SENTRY antimicrobial surveillance program report: latin american and brazilian results for 1997 through 2001

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 percent 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.

Ability of Latin America laboratories to detect antimicrobial resistance patterns: experience of the SENTRY antimicrobial surveillance program (1997-2000)

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 percent of the antimicrobial agent-organism combinations. "Very major" (false-susceptible results) and "major errors" (false-resistant results) were observed in 12 percent and 6 percent of the cases, respectively. The highest disagreements were observed for coagulase-negative Staphylococcus - oxacillin (20 percent - very major error) and Burkholderia cepacia - imipenem (21 percent - very major error). The susceptibility method with the highest agreement rate was Etest« (92 percent) > PASCO« (91 percent) > agar dilution (91 percent) > MicroScan« (90 percent) > Vitek« (87 percent). 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.

Multicenter assessment of the linezolid spectrum and activity using the disk diffusion and Etest methods: report of the Zyvox(R) antimicrobial potency study in Latin America (LA-ZAPS)

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, beta-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, MIC(90) at 0.75 microg/ml. Penicillin non-susceptible rate was 27.7 and erythromycin resistance was at 17.4. Other streptococci were also completely susceptible to linezolid (MIC(90), 1 microg/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.

Antimicrobial activity of linezolid against gram-positive cocci isolated in Brazil

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 percent of the isolates at the susceptible breakpoint (<4µg/mL). Resistance to vancomycin was very rare (99.9 percent susceptibility), and both quinupristin/dalfopristin and gatifloxacin were active against approximately 90 percent of the strains evaluated. All other comounds inhibited less than 65 percent 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.

Patogen frequency and resistance patterns in brazilian hospitals: summary of results from three years of the sentry antimicrobial surveillance program

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 occurence and antimicrobial susceptibility to patogenic 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 conclusiones: 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 patogen in general (22.8 percent-852 isolates), followed by E. coli (13.8 percent - 516 cases) and pseudomonas aeruginosa (13.3 percent - 496 cases). Staphylococcus aureus was also the most common species isolated from BSI (23.6 percent) and WSSTI (45.8 percent), and P.aeruginosa was the most frequent species isolated from patients with LRTI (29.4 percent). The main bacterial resistance problems found in this study were: imipenem resistance among P.aeruginosa (69.8 percent susceptibility) and Acinetobacter spp. (88.1 percent susceptibility): ESBL production among K. pneumoniae (48.4 percent) and E. coli (8.9 percent); resistance to third generation cephalosporin among Enterobacter spp. (68.1 percent susceptible to ceftazidime) and oxacillin resistance among S. aureus (34.0 percent) and coagulase negative staphylococci (80.1 percent). Only the carbapenems (88.1 percent to 89.3 percent susceptibility) showed reasonable activity against the Acinetobacter spp. isolates evaluated.

Perfil de sensibilidade a antimicrobianos de bactérias isoladas do trato respiratório baixo de pacientes internados em hospital brasileiros - Resultados do Programa SENTRY, 1997 e 1998 / Antimicrobial suspeceptibility of bacteria isolated from the lower respiratory tract of impatients with pneumonia in Brazilian hospital - Results from the SENTRY surveillance program, 1997 and 1998

INTRODUÇÄO: Pneumonia hospitalar é a mais fatal das infecçöes hospitalares, com taxas de mortalidade de 30 a 60 por cento. Estima-se que 15 por cento de todas as mortes associadas à hospitalizaçäo estejam diretamente relacionadas a pneumonia hospitalar. 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 hospital brasileiro. MATERIAL E MÉTODOS: Foram avaliadas 525 amostras bacterianas de 11 hospitais brasileiros, como parte do programa SENTRY. Os isolados foram testados por microdiluiçäo em caldo contra um grande número de antimicrobianos. RESULTADOS: As cinco espécies mais freqüentes foram (n/por cento): Pseudomonas aeruginosa (158/30,1 por cento), Staphylococcus aureus (103/19,6 por cento), acinetobacter spp. (68/13,0 por cento), Klebsiella spp. (50/9,5 por cento), e Enterobacter spp. (44/8,4 por cento). Essas cinco espécie representam mais de 80 por cento 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 por cento) e meropenem (69,0 por cento). Os compostos com maior atividade in vitro contra Acinetobacter spp. foram imipenem e meropenem (80,9 por cento de sensibiliade) seguido pela tetraciclina (63,2 porcento). A sensibilidade das amostras de Klebsiella spp. foi muito baixa. MIC = ug/mL para ceftriaxona ou ceftazidima, indicando produçäo de ESBL, foram os cabapenens (100 por cento de sensibilidade) e as quinolonas (92,0 por cento de sensibilidade). Ceftrixona foi ativa contra somente 56,8 por cento da amostras de Enterobacter spp. (MIC50, ó 1ug/mL), enquanto a cefapima foi detectada em 43,7 por cento dos isolados de S. aureus. As drogas mais ativas contra essa espécie foram: vancomicina, teicoplanina, quinupristin-dalfopristin e linezolida. CONCLUSÄO: 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

Antimicrobial susceptibility of Quinupristin/Dalfopristin tested against Gram-positive Cocci from Latin America: results from the global SMART (GSMART) surveillance study

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 live 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 Staphycoccus aureus (747 strains), coagulase-negative staphylococci (CoNS;446 strains), enterococci (429 strains), and various Streptococcus spp.(326 strains). Oxacillin resistance was observed in 41 percent of S. aureus (MIC,<2µg/ml or >13mm) and 40 percent of CoNS (MIC,<0.25µg/ml or >18mm). Vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC90,,0.25-1µg/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 0.5µg/ml (13 percent to 28 percent were penicillin-resistant; 12 percent to 22 percent were macrolide-resistant). Enterococci demostrated 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 technique did have quinupristin/dalfopristin MICs of>4µg/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<2µg/ml or having a zone diameter of>116mm. Comparisons to GSMART results from other continents show nerly identifical 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 bechmark for future in vitro comparisons.

Enterococcus faecalis resistant to vancomycin and teicoplanin (VanA Phenotype) isolated from a bone marrow transplanted patient in Brazil

We report for the first time in Brazil, 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 percent of enterococcal infections in Brazil. The isole was recovered from a surveillance rectal swab culture from a patient with acute lymphocytic (ALL). Identification to the species level was performed by conventional biomechanical 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,>256µg/mL) and teicoplanin (MIC, 256 µg/mL). The isolate also showed high level resistance to gentamicin and streptomycin (MICs,>1024µg/mL), but was considered susceptible to ampicillin (MIC, 4µg/mL). Although the frequency of enterococcal infections is very low in most Latin American countries, the finding of glycopeptide (VanA) resistance in E. faecalis increases concern about apreading antimicrobial resistance in this region.

Prevalence of antimicrobial resistance among respiratory tract isolates in Latin America: results from SENTRY antimicrobial surveillance program (1997-98)

One thousand seventy-three bacterial isolates were collected from patients with community acquired respiratory tract infections (CARTI) in 11 Latin American centers (7 countries) during 1997 and 1998. They were tested against numerous antimicrobial agents by the reference broth microdilution method as part of the ongoing multinational SENTRY Antimicrobial Surveillance Program. Among Streptococcus pneumonia (553 isolates), approximately 61 por cento were susceptible to penicillin. There was a great variation of the penicillin susceptibility rates among participating countries. The highest susceptibility rates were found in Argentina (76.7 porcento) and Brazil (71.9 por cento), while the lowest rate of penicillin susceptibility was detected in Mexico (33.3 por cento). High level resistance to penicillin and resistance to cefotaxime were observed in nearly 10 por cento of the isolates. The newer quinolones, levofloxacin (MIC 2 mg/mL) and gatifloxacin (MIC 0.5 mg/mL), were active against 100 por cento of the isolates tested. Among the other non-B-lactam drugs tested, the rank order of susceptibility against the pneumococci was: chloramphenicol (93.9 por cento) > clindamycin (93.2 por cento)> azithromycin (89.1 por cento) > clarithromycin (88.7 porcento) > tetracycline (78.5 por cento) > trimethoprim/sulfamethoxazole (55.7 por cento). The percentage of Haemophilus influenzae (361 isolates) isolates resistant to amoxicillin was 12.7 por cento (B-lactamase positive). Among Moraxella catarrhalis (159 isolates) isolates, only 8.2 por cento were susceptible. Clavulanic acid restored the activity of amoxicillin against both species. Trimethoprim/sulfamethoxazole was active against only 59.5 por cento of H. influenzae, while susceptibility to this compound among M. catarrhalis was 96.1 porcento. All other compounds tested were active against > 95 por cento of H. influenzae and M. catarrhalis isolates. These species were susceptible to levofloxacin (MIC90 (less or equal) 0.5 µg/mL for both) and gatifloxacin (MIC90 (less or equal) 0.03 µg/mL for both) with very low MICs. Our results indicate that penicillin resistance rates are particularly high among pneumococci in some countries. The never fluoroquinolones show and excellent potency and spectrum against pathogens causing community acquired respiratory infections in Latin America.

El programa de vigilancia antimicrobiana SENTRY en Colombia: hallazgos iniciales en tres hospitales de Medellín / The Sentry antimicrobial surveillance program in Colombia First findings in tree hospitals in Medellín

El programa SENTRY es una red de laboratorios alrededor del mundo, que vigila la prevalencia de patrones de sensibilidad / resistencia antimicrobiana en bacterias causantes de infecciones hospitalarias y de la comunidad. Este reporte resume los datos reunidos en 1997 por un laboratorio de referencia en Medellín. Los aislamientos (uno por paciente) fueron de bacteremias, neumonía, heridas de piel y tejidos blandos e infecciones urinarias. La identificación y pruebas de sensibilidad se realizarón en el laboratorio local y se confirmaron por el laboratorio coordinador en la Universidad de Iowa. Las pruebas de sensibilidad en este laboratorio se realizaron a cefalosporinas, betalactámicos, macrólidos, fluoroquinolonas, aminoglucósidos etc., utilizando microdilución en caldo. Fueron recolectados 212 aislamientos, los más frecuentes fueron: Escherichia coli (25.0 por ciento), responsible de la mayoría de las bacteremias, infecciones del tracto respiratorio inferior y tracto urinario; y Staphylococcus aureus (14.2 por ciento) obtenido de la mayoría de las infecciones de piel y tejidos blandos. La sensibilidad en bacilos gram negativos fue en su orden: imipenem (99.1 por ciento) > cefepime (92.5 por ciento) > amikacina (89.6 por ciento) > ciprofloxacina = ceftazidima = gatifloxacina = levofloxacina (88.7 por ciento) > gentamicina = trovafloxacina (87.7 por ciento) > aztreonam (85.8 por ciento) > ceftriaxona (80.2 por ciento) > piperacilina / tazobactam (77.4 por ciento) > tobramicina (76.4 por ciento) > cefuroxima (56.6 por ciento) > cefazolina (45.3 por ciento). Se encontraron aislamientos de klebsiella spp y E coli productores de betalactamasas de espectro extendido (BLEE) y una frecuenciaq alta de resistencia a fluoroquinolonas. 16.7 por ciento de Sa Aureus de resistente a oxacilina. Un aislamiento de enterococo tuvo sensibilidad intermedia a vancomicina. Estos datos pueden servir de referencia para futuros estudios y permitir la vigilancia de las tendencias de resistencia en Colombia en comparación con otros países de America Latina y el mundo

Bacterial pathogens isolated from patients with bloodstream infections in Latin America, 1997: Frequency of occurrence and antimicrobial susceptibility patterns from the SENTRY antimicrobial surveillance program

We report the antimicrobial susceptibility of 736 organisms isolated from bloodstream infections in 10 Latin American medical centers during the first six months of 1997. The data presented here is from the SENTRY Antimicrobial Surveillance Program, a comprehensive surveillance study involving 72 medical centers worldwide. The isolates were tested for in vitro susceptibility to 35 antimicrobial agents by the broth microdilution method. The five most frequently isolated species were(n/percent): Staphylococcus aureus (165/22.4 percent), Escherichia coli (118/16.0 percent), coagulase-negative staphylococci (CoNS - 115/15.6 percent), Pseudomonas aeruginosa (51/6.9 percent), Klebsiella ssp. (46/6.3 percent). Susceptibility to oxacillin was 70.9 percent for S.aureus and only 33.9 percent for CoNS. Vancomycin was active against all of staphylococci, while teicoplanin was active against 99.4 percent of S.aureus and only 90.4 percent of CoNS. The new fluoroquinolones sparfloxacin, gatifloxacin, and trovafloxacin, and the streptogramin, quinupristin/dalfopristin, were very active against these species. Only one vancomycin-resistant enterococcus was detected; however, high-level aminoglycoside resistance rates were common (66.7 percent). E.coli and Klebsiella spp. showed low susceptibilities for cefotaxime (90.7 percent and 41.3 percent) and for cefoxitin (85.6 percent and 78.3 percent respectively), indicating a high frequency of isolates that produce ESBL and/or stably derepressed ampC enzymes. These strains, phenotypically consistent with extended-spectrum ß-lactamase (ESBL) production, were typed using ribotyping and pulsed-field gel electrophoresis. The most active compounds (MIC90 in µg/mL/ percent susceptibility) against P. aeruginosa were meropenem (2/94.1 percent), followed by amikacin (>32/86.3 percent), and piperacillin alone or with tazobactam (128/84.3 percent). Ceftazidime and cefepime showed similar activity (70.6 percent susceptibility) and levofloxacin was the most active fluoroquinolone (MIC50 menor do que 0.5; 76.5 percent susceptibility) against this gram-negative species. These results show the unique pattern of bloodstream isolates for Latin America and they demonstrate the present utility of several classes of compounds against emerging antimicrobial-resistant species in this region.

Antimicrobial susceptibility of Klebsiella pneumoniae producing extended-spectrum ß-lactamase (ESBL) isolated in hospitals in Brazil

The prevalence of Klebsiella pneumoniae producing extended-spectrum ß-lactamase (ESBL) has been increasing all over the world. Infections caused by ESBL producing isolates are difficult to detect with current susceptibility test, and are difficult to treat. ESBLs confer resistence to all currently available ß-lactam, except carbapenems. In addition, ESBL, production is usually associated with resistence to other classes of antimicrobial agents such as aminoglycosides and quinolones. The objective of this study was to evaluate in vitro susceptibility patterns of ESBL producing K. pneumoniae isolated in Brazil. Seventy-two strains were tested using E test against 30 antimicrobial agents, inclusing carbapenems, second and third generation cephalosporins, aminoglycosides, quinolones, and some new compounds. The most active compounds (i.e. 100 percent susceptibility) were meropenem (MIC90,0.125µg/mL), imipenem (MIC90,0.25µg/mL), and cefotetan (MIC90,2µg/mL). Ciprofloxacin (MIC90, 1µg/mL, 94 percent susceptibility) and cefepime (MIC90, 6µg/mL, 92 percent susceptibility), were also very active against our collection of ESBL producing K. pneumoniae. None of the six aminoglycosides showed good activity against these strains (16 percent to 41 percent susceptibility) and only 39 percent of the isolates were susceptible to piperacillin/tazobactam. The results of our study indicated that the carbapenems are most active compounds against ESBL producing K.pneumoniae in Brazil, and ciprofloxaxin remains very active against these strains. Cefotetan and cefepine were also very active against ESBL producing K.pneumoniae in Brazil; however, further studies are necessary to evaluate the role of these cephalosporins in the treatment of infections due to ESBL producing strains.

A comparaçåo das atividades antimicrobianas da cefepima e da ceftazidima em 1015 amostras bacterianas isoladas no Hospital Såo Paulo / Comparasion of the activity of cefepime and ceftazidime tested in 1015 bacterial samples isolated in Hospital Såo Paulo

O presente estudo tem como objetivo comparar a atividade in vitro de uma nova cefalospirina (4ª geraçåo), a cefepima, com a da ceftadizima. Foram testadas, através da técnica de microdiluiçåo em placa, 1015 amostras bacterianas clínicas isoladas no Hospital Såo Paulo/Escola de Medicina no período de junho a julho de 1992. Para as espécies de endobactérias de maneira geral, a concentraçåo de antimicrobianos que inibiu 50 por cento das amostras (MIC 50) variou de <0,12 a u2 g/ml tanto para a cefepima quanto para a ceftazidima. Porém, a porcentagem de amostras de Enterobacter spp. sucetíveis foi superior para a cefepima (74//versus 61 por cento). Contra as amostras de Pseudomonas aeroginosa, a ceftazidima apresentou potência pouco superior àquela demonstrada pela cefepima (MIC50s de ug/ml e 8 ug/ml respectivamente), com porcentagem de sensibilidade também superior (73 por cento versus 59 por cento). Das 569 amostras de bacilos gram-negativos avaliadas, 85 por cento foram suscetíveis à ceftdazidima e 80 por cento à cefepima. Entre os cocos garm-positivos, como os Staphylococcus aureus sensíveis à oxacilina, a cefepima (MIC90 4ug/ml) foi duas a quatro vezes mais ativa que a ceftazidima (MIC90 16ug/ml). Porém, como já era esperado, as amostras de estafilococos resistentes à oxacilina e as amostras de Enterococcus faecalis foram resistentes às duas drogas testadas, com MIC50>16ug/ml. Nesse estudo, a cefepima mostrou atividade e espectro contra gram-negativos semelhantes àquele das cefasporinas de 3ª geraçåo com atividade antipseudomonas (ceftazidima). Além disso, sua atividade contra gram-positivos foi semelhante àquela demosnstrada pelas celafosporinas de 1ª geraçåo. Apesar do avanço conquistado com as cefalosporinas de 4ª geraçåo, o uso extensivo e/ou inapropriado dessas drogas facilitará o aparecimento de cepas resistentes e a pesquisa por substâncias mais ativas deve continuar