Quantitative rell-time pcr (q-pcr) for sputum sear diagnosis of pulmonary tubeerculosis among people with hiv/aids / Reaccion en cadena de polimerasa en tiempo real cuantitativa (qPCR) para el diagnostico de tuberculosis pulmonar en esputo de pacientes con VIH/sida

Objective: To assess quantitative real-time polymerase chain reaction (q-PCR) for the sputum smear diagnosis of pulmonary tuberculosis (PTB) in patients living with HIV/AIDS with a clinical suspicion of PTB. Method: This is a prospective study to assess the accuracy of a diagnostic test, conducted on 140 sputum specimens from 140 patients living with HIV/AIDS with a clinical suspicion of PTB, attended at two referral hospitals for people living with HIV/AIDS in the city of Recife, Pernambuco, Brazil. A Löwenstein-Jensen medium culture and 7H9 broth were used as gold standard. Results: Of the 140 sputum samples, 47 (33.6%) were positive with the gold standard. q-PCR was positive in 42 (30%) of the 140 patients. Only one (0.71%) did not correspond to the culture. The sensitivity, specificity and accuracy of the q-PCR were 87.2%, 98.9% and 95% respectively. In 39 (93%) of the 42 q-PCR positive cases, the CT (threshold cycle) was equal to or less than 37. Conclusion: q-PCR performed on sputum smears from patients living with HIV/AIDS demonstrated satisfactory sensitivity, specificity and accuracy, and may therefore be recommended as a method for diagnosing PTB.

Objetivo: Evaluar la Reacción en Cadena de Polimerasa en tiempo real cuantitativa (qPCR) para el diagnóstico de tuberculosis pulmonar (TBP) en esputo de pacientes con sida y sospecha clínica de TBP. Método: Se trata de un estudio prospectivo para evaluación de precisión de prueba diagnóstica, realizado en 140 muestras de esputo provenientes de 140 pacientes con sida y sospecha clínica de TBP atendidos en dos hospitales de referencia para atención VIH/sida en Recife-PE, Brasil. Se utilizó el cultivo en medios Löwenstein-Jensen y 7H9 como estándar de oro. Resultados: De las 140 muestras de esputo, 47 (33,6%) fueron positivas por el estándar de oro. La qPCR fue positiva en 42 (30%) de los pacientes. En apenas un (0.71%) caso no correspondió con el cultivo. La sensibilidad, especificidad y precisión de la qPCR fueron 87,2%, 98,9% y 95% respectivamente. De las 42 qPCR positivas en 39 (93%) el CT (threshold cycle) fue igual o inferior a 37. Conclusión: La qPCR realizada en muestra de esputo de pacientes con sida demostró sensibilidad, especificidad y precisión satisfactoria, pudiendo ser recomendada como método de diagnóstico de TBP.

A quantitative analysis of Propionibacterium acnes in lesional and non-lesional skin of patients with progressive macular hypomelanosis by real-time polymerase chain reaction

Little is known about the etiology of progressive macular hypomelanosis, although it has been suggested that Propionibacterium acnes plays an important role. While microbiological culture is commonly employed to identify Propionibacterium acnes, new identification methods have been under investigation, amongst them polymerase chain reaction. To determine the cut-off point for the number of genome copies of Propionibacterium acnes in the lesional skin of patients with progressive macular hypomelanosis as a positive marker, employing quantitative real-time polymerase chain reaction and anaerobic culture, considered gold standard. An observational study with a comparison group, included 35 patients with dermatosis, attended at the Oswaldo Cruz University Hospital, Pernambuco, Brazil, between March and May 2008. Lesional skin was compared to non-lesional skin through positive testing with real-time polymerase chain reaction and culture. The Statistical Package for Social Sciences, version 12.0, was employed for the association analysis with the McNemar test, and the cut-off point with the ROC curve for maximum values. Propionibacterium acnes was most frequently encountered in lesional areas (p<0,025). The cut-off point of Propionibacterium acnes in lesional skin was 1,333 genome copies, with a sensitivity of 87,9 percent and a specificity of 100,0 percent. Since Propionibacterium acnes is a saprophyte, identifying the cut-off point may assist in determining its positivity in lesional skin in patients suffering with this dermatosis.

Clarithromycin-resistant Helicobacter pylori in Recife, Brazil, directly identified from gastric biopsies by polymerase chain reaction / Helicobacter pylori resistente à claritromicina no Recife, Brasil, identificada diretamente de biopsias gástricas pela reação em cadeia de polimerase

CONTEXT: Clarithromycin is the most effective drug used in the eradication of infection by Helicobacter pylori. Due to worldwide increase in resistance, pre-treatment susceptibility testing for clarithromycin is recommended. OBJECTIVES: To evaluate the prevalence of clarithromycin resistance of H. pylori in Recife, a city in Northeast Brazil. METHODS: From January 2006 to December 2007, 114 gastric biopsy samples positive for H. pylori at culture were directly assayed by polymerase chain reaction (PCR) to detect the most frequent point mutations involved in clarithromycin resistance. Results were compared with those obtained by Etests. RESULT: Molecular and phenotypic methods showed 111 (97.4 percent) susceptible or resistant concordant results. PCR detected 3 (2.6 percent) biopsy specimens with H. pylori-resistant genotypes, which were misdiagnosed as susceptible by Etests. In Recife, based on PCR results, primary clarithromycin resistance was found in 15 (16.5 percent) patients, prevalence close to that observed in Southeast Brazil. Resistance increased to 52 percent among previously treated patients. The point mutation A2143G was present in 20 (71.4 percent) of specimens and A2142G, in 8 (28.6 percent) of specimens. A2142C was not found. CONCLUSION: In Recife, the prevalence of primary clarithromycin resistance, 16.5 percent, showed the need for pretreatment susceptibility testing in H. pylori infections.

CONTEXTO: Claritromicina é a droga mais eficaz usada na erradicação da infecção pelo H. pylori. Devido ao aumento mundial da resistência, o teste de susceptibilidade à claritromicina pré-tratamento é recomendado. OBJETIVO: Determinar a prevalência de H. pyloriclaritromicina resistente em Recife, PE, Brasil. MÉTODO: De janeiro de 2006 a dezembro de 2007, 114 biopsias gástricas positivas à cultura para H. pylori foram diretamente analisadas pela reação em cadeia da polimerase (PCR), para detectar a frequência das mutações em ponto que envolvem a resistência à claritromicina. Os resultados foram comparados com os obtidos pelos E-testes. RESULTADO: Os métodos molecular e fenótipo fenotípico mostraram 111 (97.4 por cento) resultados concordantes, sensíveis ou resistentes. A PCR detectou três (2.6 por cento) espécimes de H. pyloricom genótipo resistente, diagnosticados erroneamente como sensíveis pelo E-teste. No Recife, baseando-se nos resultados da PCR, a resistência primária à claritromicina foi encontrada em 15 (16.5 por cento) pacientes, esta prevalência também foi observada no sudeste do Brasil. Entre os pacientes previamente tratados, a resistência elevou-se para 52 por cento. A mutação em ponto A2143G foi observada em 20 (71.4 por cento) dos espécimes e a A2142G, em 8 (28.6 por cento). A mutação A2142C não foi encontrada. CONCLUSÃO: No Recife, a prevalência da resistência a claritromicina, 16.5 por cento, mostrou a necessidade de realização dos testes de susceptibilidade prétratamento nas infecções por H. pylori.

Metallo-beta-lactamase producing Pseudomonas aeruginosa strains isolated in hospitals in Recife, PE, Brazil

De 24 linhagens hospitalares de Pseudomonas aeruginosa provenientes de Recife, Brasil, 15 (62 per center) produziram metalo-b-lactamase. Tais isolados foram resistentes às principais drogas antipseudomonas, exceto polimixina B e aztreonam. A enzima responsável pela resistência aos carbapanêmicos pertence à classe SPM-1 e o gene envolvido, blaspm-1, provavelmente é plasmidial.