RESUMEN
Streptococcus pneumoniae (Spn) is a leading cause of community-acquired pneumonia (CAP), yet existing diagnostic tools remain inadequate. We aimed to evaluate laboratory and radiological methods for detecting pneumococcal aetiology in CAP patients and to estimate Spn prevalence in this group. All-aged patients hospitalized with clinically defined CAP in northern Togo were enrolled during 2010-2013. Latent class analysis pooled results of semi-automated blood culture (SABC), whole blood lytA real-time polymerase chain reaction (rt-PCR), serum C-reactive protein (CRP), and chest radiography (CXR) and categorized patients as likely pneumococcal or non-pneumococcal CAP. We enrolled 1684 patients; 1501 had results for all tests. CXR, SABC, lytA rt-PCR and CRP >71·2 mg/l had sensitivities of 94% [95% confidence interval (CI) 87-100], 13% (95% CI 10-16), 17% (95% CI 14-21) and 78% (95% CI 75-80), and specificities of 88% (95% CI 84-93), 100% (95% CI 99-100), 97% (95% CI 96-99) and 77% (95% CI 75-79), respectively. Pneumococcal attributable proportion was 34% (95% CI 32-37), increasing with age and in men. We estimated that Spn caused one third of CAP. Whole blood lytA rt-PCR was more sensitive than SABC; both had low sensitivity and high specificity. Conversely CXR was highly sensitive and reasonably specific; it could be a useful tool for epidemiological studies aiming to define Spn pneumonia incidence across all ages.
Asunto(s)
Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/epidemiología , Pruebas Diagnósticas de Rutina/métodos , Neumonía Neumocócica/diagnóstico , Neumonía Neumocócica/epidemiología , Radiografía Torácica/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Técnicas Bacteriológicas/métodos , Proteína C-Reactiva/análisis , Infecciones Comunitarias Adquiridas/diagnóstico por imagen , Humanos , Neumonía Neumocócica/diagnóstico por imagen , Prevalencia , Sensibilidad y Especificidad , Togo/epidemiologíaRESUMEN
The recent emergence of Neisseria meningitidis W135 as a cause of epidemic bacterial meningitis and the availability of a trivalent ACW135 vaccine have created a need for accurate and timely meningococcal serogroup determination for organization of epidemic vaccine response. The sensitivity and specificity of the Pastorex meningitis kit (Bio-Rad) to identify serogroups A and W135 in the African meningitis belt was assessed using PCR testing as the gold standard. The sensitivity and specificity for serogroups A and W135 were 87 and 85%, respectively, while the specificities were 93 and 97%. The positive and negative likelihood ratios for A were 12 and 0.14 and for W135 were 33 and 0.16. The positive and negative predictive values, computed to simulate an epidemic of meningococcal meningitis with an estimated 70% prevalence of N. meningitidis among suspected cases, were 97% and 75% for A and 99% and 73% for W135. In remote locations of the African meningitis belt, latex agglutination is the only currently available test that can rapidly determine meningococcal serogroup. This study showed that latex agglutination performs well and could be used during the epidemic season to determine appropriate vaccine response.
Asunto(s)
Pruebas de Fijación de Látex/normas , Meningitis Bacterianas/diagnóstico , Neisseria meningitidis Serogrupo A/aislamiento & purificación , Neisseria meningitidis Serogrupo W-135/aislamiento & purificación , Juego de Reactivos para Diagnóstico , Anticuerpos Monoclonales/inmunología , Antígenos Bacterianos/líquido cefalorraquídeo , Antígenos Bacterianos/inmunología , Burkina Faso , Humanos , Pruebas de Fijación de Látex/métodos , Meningitis Bacterianas/prevención & control , Neisseria meningitidis Serogrupo A/inmunología , Neisseria meningitidis Serogrupo W-135/inmunología , Niger , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y EspecificidadRESUMEN
In order to gain a better understanding of the molecular epidemiology of Mycobacterium bovis isolates in Cameroon, 75 isolates of M. bovis collected in three provinces of northern Cameroon were studied by spoligotyping. For 65 of these isolates, typing was also carried out by pulsed-field gel electrophoresis (PFGE) with DraI, and 18 of the isolates were also typed by restriction fragment length polymorphism (RFLP) analysis with probe IS6110-RHS. Molecular typing of the isolates by these techniques revealed a high degree of homogeneity, with 10 spoligotypes for 75 isolates, four PFGE profiles for 65 isolates, and three RFLP types for 18 isolates. Some types were present in the three different provinces, while some were confined to one or two areas. These results suggest that geographical mapping of M. bovis strains could be helpful for the control of bovine tuberculosis at the regional level. An interesting feature of all the spoligotypes was the absence of spacer 30, suggesting a common origin for all of the Cameroon isolates tested; an evolutionary scenario for the isolates is discussed. In addition, a comparison of the three techniques showed that for M. bovis strain differentiation in Cameroon and in surrounding countries, spoligotyping would be a more discriminating and practical tool for molecular typing than the other two techniques used in this study.