Ventilator associated pneumonia: comparison between quantitative and qualitative cultures of tracheal aspirates

INTRODUCTION: Deferred or inappropriate antibiotic treatment in ventilator-associated pneumonia (VAP) is associated with increased mortality, and clinical and radiological criteria are frequently employed to establish an early diagnosis. Culture results are used to confirm the clinical diagnosis and to adjust or sometimes withdraw antibiotic treatment. Tracheal aspirates have been shown to be useful for these purposes. Nonetheless, little is known about the usefulness of quantitative findings in tracheal secretions for diagnosing VAP. METHODS: To determine the value of quantification of bacterial colonies in tracheal aspirates for diagnosing VAP, we conducted a prospective follow-up study of 106 intensive care unit patients who were under ventilatory support. In total, the findings from 219 sequential weekly evaluations for VAP were examined. Clinical and radiological parameters were recorded and evaluated by three independent experts; a diagnosis of VAP required the agreement of at least two of the three experts. At the same time, cultures of tracheal aspirates were analyzed qualitatively and quantitatively (10(5 )colony-forming units [cfu]/ml and 10(6 )cfu/ml) RESULTS: Quantitative cultures of tracheal aspirates (10(5 )cfu/ml and 10(6 )cfu/ml) exhibited increased specificity (48% and 78%, respectively) over qualitative cultures (23%), but decreased sensitivity (26% and 65%, respectively) as compared with the qualitative findings (81%). Quantification did not improve the ability to predict a diagnosis of VAP. CONCLUSION: Quantitative cultures of tracheal aspirates in selected critically ill patients have decreased sensitivity when compared with qualitative results, and they should not replace the latter to confirm a clinical diagnosis of VAP or to adjust antimicrobial therapy

Mycobacterium haemophilum: Emerging or Underdiagnosed in Brazil?

Fleury Ctr Diagnost Med, Microbiol Sect, BR-04344070 Sao Paulo, BrazilUniv Fed Sao Paulo, Sao Paulo, BrazilOswaldo Cruz Hosp, Sao Paulo, BrazilAlbert Einstein Hosp, Sao Paulo, BrazilSirio Libanes Hosp, Sao Paulo, BrazilServidores Estado Hosp, Rio De Janeiro, BrazilAlianca Hosp, Salvador, BA, BrazilLamina Lab, Rio De Janeiro, BrazilInst Oswaldo Cruz, BR-20001 Rio De Janeiro, BrazilUniv Fed Sao Paulo, Sao Paulo, BrazilWeb of Scienc

Staphylococcus cohnii spp urealyticus: case report on an uncommon pathogen

Coagulase-negative Staphylococcus has emerged as an important agent in nosocomial infections. In this study, we report a case of bacteremia associated with a central venous catheter, caused by Staphylococcus cohnii spp urealyticus that was isolated in blood cultures from a 53-year-old male patient who was admitted to a general hospital in the city of São Paulo. We discuss in this report the difficulty in routinely identifying this microorganism in the clinical microbiology laboratory. Staphylococcus cohnii spp urealyticus is a microorganism found in human skin as part of the normal microbiota, and it can cause serious infections in humans, in some situations.Staphylococcus coagulase negativos tem surgido como importantes agentes em infecções de pacientes hospitalizados. Neste estudo, relatamos o caso de bacteremia associada a cateter venoso central devido a Staphylococcus cohnii spp urealyticus isolado em hemocultura de um paciente do sexo masculino, 53 anos, internado em hospital geral da cidade de São Paulo. Discutimos nesse relato a dificuldade em identificar rotineiramente esse microrganismo no Laboratório de Microbiologia Clínica. Staphylococcus cohnii spp urealyticus é um microrganismo encontrado na pele dos seres humanos como parte da microbiota normal, podendo em algumas situações causar sérias infecções em humanos

Estudo comparativo de detecção de metapneumovírus humano pelos métodos de PCR e imunofluorescência direta

INTRODUÇÃO: O metapneumovírus humano (MPVh) causa infecções respiratórias em crianças, adultos e idosos imunodeprimidos. O diagnóstico é realizado por imunofluorescência (IF) ou biologia molecular. OBJETIVO: Detectar o MPVh em amostras clínicas pelos métodos de reação em cadeia da polimerase (PCR) e imunofluorescência direta (IFD). RESULTADOS: Das 202 amostras, a positividade foi de 2% e 4% para IFD e RT-PCR, respectivamente. Sensibilidade e especificidade da IFD foram de 50% e 100%, respectivamente, considerando o PCR com transcrição reversa (RT-PCR) como padrão-ouro. CONCLUSÃO: O estudo indica a RT-PCR como o melhor método para a identificação de MPVh em amostras clínicas respiratórias e mostra a importância da padronização do teste para inclusão na rotina laboratorial

Performance of the dipstick screening test as a predictor of negative urine culture

<div><p>ABSTRACT Objective To investigate whether the urine dipstick screening test can be used to predict urine culture results. Methods A retrospective study conducted between January and December 2014 based on data from 8,587 patients with a medical order for urine dipstick test, urine sediment analysis and urine culture. Sensitivity, specificity, positive and negative predictive values were determined and ROC curve analysis was performed. Results The percentage of positive cultures was 17.5%. Nitrite had 28% sensitivity and 99% specificity, with positive and negative predictive values of 89% and 87%, respectively. Leukocyte esterase had 79% sensitivity and 84% specificity, with positive and negative predictive values of 51% and 95%, respectively. The combination of positive nitrite or positive leukocyte esterase tests had 85% sensitivity and 84% specificity, with positive and negative predictive values of 53% and 96%, respectively. Positive urinary sediment (more than ten leukocytes per microliter) had 92% sensitivity and 71% specificity, with positive and negative predictive values of 40% and 98%, respectively. The combination of nitrite positive test and positive urinary sediment had 82% sensitivity and 99% specificity, with positive and negative predictive values of 91% and 98%, respectively. The combination of nitrite or leukocyte esterase positive tests and positive urinary sediment had the highest sensitivity (94%) and specificity (84%), with positive and negative predictive values of 58% and 99%, respectively. Based on ROC curve analysis, the best indicator of positive urine culture was the combination of positives leukocyte esterase or nitrite tests and positive urinary sediment, followed by positives leukocyte and nitrite tests, positive urinary sediment alone, positive leukocyte esterase test alone, positive nitrite test alone and finally association of positives nitrite and urinary sediment (AUC: 0.845, 0.844, 0.817, 0.814, 0.635 and 0.626, respectively). Conclusion A negative urine culture can be predicted by negative dipstick test results. Therefore, this test may be a reliable predictor of negative urine culture.</p></div

Identification of Clostridium difficile Asymptomatic Carriers in a Tertiary Care Hospital

Background. The diagnosis of Clostridium difficile infection (CDI) increases concern that asymptomatic carriers of toxigenic C. difficile may be diagnosed with CDI. Methods. A matched case control study was conducted in inpatients in a tertiary care center. The first 50 patients with diarrhea and a positive polymerase chain reaction (PCR) test beginning February 1, 2015, were identified as cases. Control patients were hospitalized patients receiving antibiotics, but with no diarrhea, housed in a room as close as possible to each case during the same admission time. A convenience sample of healthcare workers who cared for C. difficile infected patients was also tested. Results. We found two positive PCR results for C. difficile in controls (4.1%). None of these healthcare workers were positive for C. difficile by PCR. There was no difference between groups with respect to overall antibiotic use before the requested PCR for Clostridium difficile (p=0.359). The majority of cases had a high proportion of gastrointestinal disorders (71.4%) compared with control (8.2%), p<0.001. Patients with neoplasia had a higher chance of being identified as cases (p=0.041). Conclusions. PCR should not be the only diagnostic tool but should be complementary to other methods and to the medical history