Resumo Contexto O diagnóstico do agente etiológico é essencial para o tratamento das infecções de endoprótese, pois representam uma importante complicação do tratamento endovascular. A sonificação dos tecidos pode ser uma técnica usada para auxiliar na detecção de bactérias produtoras de biofilme. Objetivos Avaliar a infecção da aorta dos porcos após o implante de stents de nitinol revestidos com politetrafluoretileno (ePTFE) ou Dacron, infectados com Staphylococcus epidermidis, produtor de biofilme. O espessamento intimal e a resposta inflamatória na parede aórtica também foram avaliados. Métodos Onze stents de nitinol revestidos com ePTFE e 10 stents de Dacron infectados com cepas de S. epidermidis foram implantados na aorta infrarrenal de 21 porcos com 8 semanas de idade. Após duas semanas, a aorta contendo os stents foi removida. Um misturador de vórtice e ultrassom foram utilizados para homogeneizar as amostras e remover o biofilme. Posteriormente, o número de unidades formadoras de colônias foi contado. Resultados Não houve diferenças significativas no número de unidades formadoras de colônias ou inflamação na parede arterial entre os dois grupos. Todas as culturas de stent aórtico foram positivas para S. epidermidis, exceto uma no grupo Dacron. Conclusões Não houve diferenças significativas na resposta inflamatória ou na taxa de infecção entre os stents revestidos de ePTFE e Dacron, infectados ativamente pelo S. epidermidis produtor de biofilme. O espessamento intimal e a resposta inflamatória à infecção das endopróteses foram semelhantes. Esses resultados sugerem que os dois materiais de revestimento de stent mais amplamente utilizados têm uma taxa de infecção semelhante.

Abstract Background Diagnosis of the etiologic agent of endoprosthesis infections is essential to enable treatment, since these infections constitute important complications of endovascular procedures. Sonication of explanted tissue and materials is a technique that can be used to facilitate detection of biofilm-producing bacteria. Objectives To evaluate infection of pigs' aortas after implantation of nitinol stents coated with polytetrafluoroethylene (ePTFE) or Dacron, previously infected with biofilm-producing Staphylococcus epidermidis. Intimal thickening and the inflammatory response in the aortic wall were also evaluated. Methods 11 ePTFE-coated nitinol stents and 10 Dacron stents infected with S. epidermidis strains were implanted in the infrarenal aorta of 21 8-week-old pigs. After 2 weeks, the aorta containing the stents was removed. A vortex mixer and ultrasound were used to homogenize the samples and remove the biofilm. Subsequently, the number of colony-forming units was counted. Results There were no significant differences between the two groups in terms of the number of colony-forming units or of inflammation in the arterial wall. With the exception of one specimen from the Dacron group, all aortic stent cultures were positive for S. epidermidis. Conclusions There were no significant differences in the inflammatory response or infection rate between ePTFE and Dacron-coated stents actively infected with biofilm-producing S. epidermidis. Intimal thickening and the inflammatory response to infection of endoprostheses were similar. These results suggest that the two most widely used stent lining materials have a similar infection rate.

BACKGROUND In high tuberculosis (TB) burden countries, there are few data on the performance of new molecular commercialised assays developed locally. OBJECTIVE To evaluate the performance of a new molecular commercialised assay for TB diagnosis (Detect-TB) in three laboratories. METHODS A total of 302 sputum samples from an equal number of patients with presumptive diagnosis of pulmonary tuberculosis (PTB) were submitted for routine smear microscopy, culture, and Detect-TB assay at three different sites in Brazil (the cities of Caxias do Sul, São Paulo and Canoas). FINDINGS Seventy four (24.7%) TB cases were diagnosed (65 bacteriologically confirmed). When compared to smear microscopy/culture results, the overall sensitivity and specificity of Detect-TB assay was 84.6% (CI 95%; 73.7-91.6) and 93.1% (CI 95%; 89.1-95.8), respectively. When compared to bacteriological and clinical diagnostic criteria, the sensitivity and specificity of Detect-TB assay was 74.3% (CI 95%; 63.3-82.9) and 92.9% (CI 95%; 88.7-95.6), respectively. Among the three sites - Caxias do Sul, São Paulo and Canoas - the sensitivity and specificity were respectively 94.7% and 97.8%; 71.4% and 93.9%, 82.1% and 88.9%. MAIN CONCLUSIONS These findings suggest that the Detect-TB assay could be applied routinely in reference laboratories across different regions in Brazil.

OBJECTIVES: To determine the prevalence of class A extended spectrum β-lactamases (ESBL)-producing Escherichia coli and Klebsiella spp., and to investigate clonality among ESBL-producing isolates of nosocomial and community infections. METHODS: The study involved 354 nosocomial infections samples and 992 community infections samples, obtained between 2003 and 2006 at Caxias do Sul, RS. The detection of ESBL was performed by the disk-diffusion test. Presence of blaCTX-M, blaSHV and blaTEM β-lactamase genes was evaluated by PCR, and genomic typing was determined by pulsed-field gel electrophoresis analysis. RESULTS: Higher frequency of ESBL-producing isolates were detected among nosocomial samples of E. coli (6.7%) and Klebsiella (43.7%), than those obtained from community infections (0.4% and 2.6%). blaTEM and blaCTX were the most prevalent ESBL gene families in both E. coli and Klebsiella isolates. Different pulsotypes were obtained among ESBL-producing E. coli and 11 clones for Klebsiella spp., which occurred over the years and in different hospital wards. Among ESBL-producing K. pneumoniae, 74.3% transferred ESBL genes by conjugation and exhibited concomitant decreased aminoglycosides susceptibility. CONCLUSION: ESBL-producing E. coli, and especially K. pneumoniae are essentially a nosocomial problem, and their dissemination to the community is relatively limited. The great genetic variability observed among ESBL-producing bacteria indicates polyclonal spread and high transference of ESBL genes between bacteria in the hospital environment. This information is of paramount importance for nosocomial infection control.

Aeromonas foram isoladas de 27 (6.6%) dos 408 pacientes admitidos com gastroenterite aguda em dois hospitais do Rio Grande do Sul, Brasil. Os isolados foram classificados com A. hydrophila (51.8%), A. caviae (40.8%), e A. veronii biotype sobria (7.4%). A maior prevalência de Aeromonas ocorreu em lactantes e crianças. Genes (aerA -aerolisina/hemolisina, ahpA -serina-protease, satA - glicerofosfolipidio-colesterol aciltransferase, lipA -lipase, e ahyB -elastase) e factores (atividade hemolítica, proteolítica, lipolítica, e formação de biofilme) de virulência foram identificados na maioria dos isolados de A. hydrophila e A. veronii biotype sobria, com freqüências menores em A. caviae. Todos os isolados de Aeromonas apresentaram resistência a ampicilina, ticarcilina/ácido clavulânico, cefalotina e cefazolina, e a maior parte (>70%) exibiram resistência a imipenem, carbenicilina, amoxacilina/sulbactam e piperacilina. Resistência múltipla foi evidenciada em 29,6% dos isolados. Os antibióticos mais eficientes foram as quinolonas (ciprofloxacina e norfloxacina) e os aminoglicosídicos (amicacina e netilmicina).

Aeromonas were isolated from 27 (6.6%) of 408 patients admitted with acute gastroenteritis in two hospitals at Rio Grande do Sul, Brazil. Isolates were classified as A. hydrophila (51.8%), A. caviae (40.8%), and A. veronii biotype sobria (7.4%). The highest prevalence of Aeromonas associated infections occurred in lactants and children. Virulence genes (aerA -aerolysin/hemolysin, ahpA -serine-protease, satA - glycerophospholipid-cholesterol acyltransferase, lipA -lipase, and ahyB -elastase) and virulence factors (hemolytic, proteolitic, lipolitic activities, and biofilm formation) were identified in most A. hydrophila and A. veronii biotype sobria isolates, with lower frequencies on A. caviae. All Aeromonas isolates were resistant to ampicillin, ticarcillin/clavulanic acid, cephalotin, and cephazolin, and most of them (>70%) exhibited resistance to imipenem, carbenicillin, amoxillin/sulbactan, and piperacillin. Multiple-resistance, more than four antibiotics, was evidenced in 29.6% of the isolates. The most efficient antibiotics were the quinolones (ciprofloxacin and norfloxacin), and the aminoglycosides (amikacin and netilmicin).