Polymyxin-Resistant Acinetobacter spp. Isolates: What is Next?

Univ Fed Sao Paulo, Div Infect Dis, Lab Especial Microbiol Clin, BR-04025010 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Div Infect Dis, Lab Especial Microbiol Clin, BR-04025010 Sao Paulo, SP, BrazilWeb of Scienc

Prevalence of vancomycin-resistant Enterococcus fecal colonization among kidney transplant patients

BACKGROUND: End stage renal disease patients are at risk of Vancomycin-Resistant Enterococcus (VRE) infections. The first reports of VRE isolation were from hemodialysis patients. However, to date, VRE fecal colonization rates as well as associated risk factors in kidney transplant patients have not yet been established in prospective studies. METHODS: We collected one or two stool samples from 280 kidney transplant patients and analysed the prevalence of VRE and its associated risk factors. Patients were evaluated according to the post-transplant period: group 1, less than 30 days after transplantation (102 patients), group 2, one to 6 months after transplantation (73 patients) and group 3, more than 6 months after transplantation (105 patients). RESULTS: The overall prevalence rate of fecal VRE colonization was 13.6% (38/280), respectively 13.7% for Group 1, 15.1% for group 2 and 12.4% for group 3. E. faecium and E. faecalis comprised 50% of all VRE isolates. No immunologic variables were clearly correlated with VRE colonization and no infections related to VRE colonization were reported. CONCLUSION: Fecal VRE colonization rates in kidney transplant patients were as high as those reported for other high-risk groups, such as critical care and hemodialysis patients. This high rate of VRE colonization observed in kidney transplant recipients may have clinical relevance in infectious complications

Avaliação da qualidade dos discos com antimicrobianos para testes de disco-difusão disponíveis comercialmente no Brasil

Introdução: O teste de suscetibilidade a antimicrobianos representa um dos testes de maior importância clínica realizados pelo laboratório de microbiologia. Devido ao grande número de antimicrobianos e à complexidade dos mecanismos de resistência desenvolvidos pelas bactérias, fica muito difícil hoje a detecção de problemas nos testes de suscetibilidade pela simples avaliação dos resultados obtidos. Sendo assim, é extremamente importante que haja uma avaliação constante da qualidade destes testes. Objetivo: O objetivo do presente estudo foi avaliar a qualidade dos discos de antimicrobianos comercializados no Brasil. Material e métodos: Foram avaliados discos de 18 antimicrobianos obtidos de cinco diferentes fontes comerciais, os quais foram testados frente a quatro cepas bacterianas oriundas da ATCC, pelo método de difusão em ágar, seguindo as recomendações do National Committee for Clinical Laboratory Standards (NCCLS). Cada teste foi repetido 20 vezes. Resultados: Nenhuma das marcas apresentou desempenho satisfatório para o uso na rotina de um laboratório de microbiologia. O melhor desempenho foi apresentado pela marca Cecon®, com 89,6% de concordância. A marca Sensifar® apresentou taxa de concordância geral semelhante (90,8%). A marca com o pior desempenho foi a Pimenta Abreu®, com apenas 58,6% de concordância. Conclusão: Os resultados do presente estudo indicam que os discos de antimicrobianos comercializados no Brasil são de baixa qualidade, possivelmente refletindo a falta de controle de qualidade na produção e/ou estocagem dos produtos antes da sua distribuição. Esses dados chamam a atenção para a necessidade de implantação de sistemas efetivos de fiscalização da comercialização desses produtos e de programas criteriosos de controle de qualidade por parte dos laboratórios que os utilizam

Pathogen frequency and resistance patterns in brazilian hospitals : summary of results from three years of the SENTRY Antimicrobial Surveillance Program

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

Antimicrobial Activities of Tigecycline and Other Broad-Spectrum Antimicrobials Tested against Serine Carbapenemase- and Metallo-β-Lactamase-Producing Enterobacteriaceae: Report from the SENTRY Antimicrobial Surveillance Program▿

A total of 104 carbapenemase (serine- and metallo-β-lactamase [MβL])-producing strains of the Enterobacteriaceae family collected from 2000 to 2005 in medical centers distributed worldwide were tested against tigecycline and 25 comparators by reference broth microdilution methods. The most frequent carbapenemase was KPC-2 or -3 (73 strains), followed by VIM-1 (14), IMP-1 (11), SME-2 (5), and NMC-A (1). All serine carbapenemases were detected in the United States, while MβL-producing strains were isolated in Europe. Carbapenemase-producing Enterobacteriaceae showed high rates of resistance to most antimicrobial agents tested. The rank order of in vitro activity against these strains was as follows: tigecycline (100.0% susceptible) > polymyxin B (88.1%) > amikacin (73.0%) > imipenem (37.5%). Tigecycline was very active (MIC90, 1 μg/ml) against this significant, contemporary collection of well-characterized strains and appears to be an excellent option compared to the polymyxins for treatment of infections caused by these multidrug-resistant Enterobacteriaceae

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% 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