To our knowledge, this is the first study to report plasma concentrations over time and urinary recovery of polymyxin B in critically ill patients after intravenous administration. Polymyxin B is eliminated mainly by nonrenal pathways, and the total body clearance appears to be relatively insensitive to renal function. Additional investigations are required to assess the appropriateness of currently recommended doses of this drug for the treatment of severe infections in critically ill persons.

SUMMARYA case-control study, involving patients with positive blood cultures for Klebsiella pneumoniae (KP) or Escherichia coli (EC) EC and controls with positive blood cultures for non-ESBL-KP or EC, was performed to assess risk factors for extended-spectrum-blactamase (ESBL) production from nosocomial bloodstream infections (BSIs). Mortality among patients with BSIs was also assessed. The study included 145 patients (81, 59.5% with K. pneumoniae and 64, 44.1% with E. coli BSI); 51 (35.2%) isolates were ESBL producers and 94 (64.8%) nonproducers. Forty-five (55.6%) K. pneumoniae isolates were ESBL producers, while only six (9.4%) E. coli isolates produced the enzyme. Multivariate analysis showed that recent exposure to piperacillin-tazobactam (adjusted Odds Ratio [aOR] 6.2; 95%CI 1.1-34.7) was a risk factor for ESBL BSI. K. pneumoniae was significantly more likely to be an ESBL-producing isolate than E. coli (aOR 6.7; 95%CI 2.3-20.2). No cephalosporin class was independently associated with ESBLs BSI; however, in a secondary model considering all oxymino-cephalosporins as a single variable, a significant association was demonstrated (aOR 3.7; 95%CI 1.3-10.8). Overall 60-day mortality was significantly higher among ESBL-producing organisms. The finding that piperacillintazobactam use is a risk factor for ESBL-production in KP or EC BSIs requires attention, since this drug can be recommended to limit the use of third-generation cephalosporins.

Coagulase-negative staphylococci (CNS) are the major cause of nosocomial infections. Methicillinresistant strains are particularly important because they narrow therapeutic options. Detecting methicillin resistance among CNS has been a challenge for years. The objective of this study was to determine the accuracy of an agar screening test (0 . 6 and 4 ìg oxacillin ml À1 ), disc diffusion and the automated MicroScan system to characterize methicillin resistance among CNS. One hundred and seventy five strains were analysed: 41 . 1 % Staphylococcus epidermidis and 59 . 9 % other species; 69 . 1 % were mecA-positive. The results showed that the methods have optimal correlation with the detection of mecA gene for S. epidermidis, Staphylococcus hominis and Staphylococcus haemolyticus. However, accuracy of the tests is impaired when less common species are analysed. The only 100 % accurate test was agar screening with 4 ìg oxacillin ml À1 .

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We evaluated clinical outcomes and molecular epidemiology of methicillin-resistant Staphylococcus aureus carrying SCCmecIV recovered from patients who attended at a teaching hospital from Porto Alegre, Brazil. All Panton-Valentine leukocidin (PVL)-producer isolates belonged to clonal complex (CC) 30 (11 isolates, related to Oceania Southwest Pacific clone [OSPC]), and the PVL-negative isolates were typed as CC5 (2 isolates, related to the pediatric clone). Five patients had health care-associated infections (HCAIs) with hospital-onset, 5 HCAIs with community-onset, and 3 community-acquired infections without risks. A high overall mortality (30.8%) was found. This study show that OSPC isolates are not only causing community-associated infections but are also involved in HCAI in our country.

RESUMO JUSTIFICATIVA E OBJETIVOS:O Strongyloides stercoralis é um agente comum de infecção do trato gastrintestinal. Em pacientes imunodeprimidos este nematódeo pode causar hiper-infecção, com manifestações pulmonares e sepse por germes gram-negativos. O objetivo deste relato foi apresentar um caso com evolução letal e ressaltar a importância do diagnóstico e do tratamento precoce. RELATO DO CASO: Paciente do sexo masculino, 60 anos, com diagnóstico de tumor de timo, submetido a tratamento cirúrgico, radioterapia e quimioterapia. Foi consultado na emergência relatando queixa de diarréia e dispnéia, sendo admitido na UTI após apresentar quadro de insufi ciência respiratória aguda hipoxêmica e choque refratário, evoluindo para óbito. SUMMARY BACKGROUND AND OBJECTIVES: StrongyloidesStercoralis is a common cause of gastrointestinal infection. This nematode can produce an overwhelming hyperinfection syndrome, especially in the immunocompromised patient. Typically, patients present with pulmonary symptoms, but subsequently they can acquire Gram-negative sepsis. The objective of this report is to describe a lethal case and call attention to the importance of early diagnosis and treatment. CASE REPORT: Male patient, 60 year-old with diagnosis of timoma, treated with surgery, radiotherapy and chemotherapy in the past. He presented to the emergency room complaining of diarrhea and dyspnea, and then transferred to the ICU after development of hypoxemic acute respiratory failure and refractory septic shock, and despite treatment the patient died. A bronchial sample of sputum showed Strongyloides stercoralis worms. CONCLUSIONS: Strongyloides stercoralis infection symptoms are usually mild, but in the setting of impaired host immunity, a disseminated and severe illness may occur. Clinicians must be aware for patients from endemic areas. Diagnosis may be established through sputum and stool examination for Strongyloides stercoralis worms.

Coagulase-negative staphylococci (CoNS) (accuracy of 96.8 vs 78.8%, respectively); isolates from the following species had no precise identification: Staphylococcus haemolyticus, S. simulans, and S. capitis. Both systems were similar in the characterization of methicillin resistance. The higher discrepancies for gene mec detection were observed among species other than S. epidermidis (S. hominis, S. saprophyticus, S. sciuri, S. haemolyticus, S. warneri, S. cohnii), and those with borderline MICs.Key words: coagulase-negative staphylococci -methicillin -automated systems Coagulase-negative staphylococci (CoNS) become important nosocomial pathogens, being, in many institutions, among the main etiological agents of nosocomial bacteremias (Cockerill et al. 1997, Hussain et al. 1998, Petinaki et al. 2001. Many clinical laboratories do not identify CoNS in species level when these microrganisms are detected in blood or in cerebrospinal fluid. However, as the significance of CoNS as pathogens has been increased, it has become more important to know the epidemiology and the pathogenic potential of species, individually. This might be particularly important considering blood culture isolates, since it is often difficult to determine the clinical significance of an individual isolate. There are numerous commercial systems and kits available nowadays for the identification of CoNS species (Kloos & Bannerman 1999).Resistance to methicillin among these microrganisms is a matter of concern because of the high and increasing levels detected. In Brazil, a multicenter study showed that methicillin resistance was observed in 87.7% of CoNS isolated from bloodstream infections (Sader et al. 1999). The accurate detection of methicillin resistance among CoNS isolates in the clinical laboratory is important to guide therapy and to promote the correct use of glycopeptides (Hussain et al. 1998, Yamazumi et al. 2001.This work was performed to evaluate the accuracy of two automated systems in the identification of species and determination of methicillin resistance, considering as gold standard the conventional biochemical tests and the characterization of mecA gene by polymerase chain reaction (PCR), respectively. MATERIALS AND METHODSBacterial samples -Ninety-four consecutive CoNS isolates were included in the study, coming from blood cultures of patients hospitalized in the Complexo Hospitalar Irmandade Santa Casa de Misericórdia in Porto Alegre. The isolates were kept at -20 o C in skim milk (Difco), plus 20% glycerol. The quality control of the tests was done using the Staphylococcus hominis ATCC 27844, S. epidermidis ATCC 12228, S. saprophyticus CCM 883, S. haemolyticus CCM 2737, and S. aureus ATCC 33591. Identification of bacterial isolates by conventional biochemical tests -The isolates were identified by conventional biochemical tests based on Manual for Clinical Microbiology (Bannerman 2003). The following test were used: catalase test, coagulase test, clumping factor, urease activity, ornitine decarboxilation, PYRase activi...

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