RESUMEN
Multidrug-resistant tuberculosis is an increasing health problem worldwide, especially in developing countries. The PCR-UHG-Rif assay, which detects mutations within the rpoB gene associated with rifampin resistance, was evaluated for its ability and reliability to detect and identify drug-resistant Mycobacterium tuberculosis in a developing country where tuberculosis is highly endemic.
Asunto(s)
Resistencia a Múltiples Medicamentos/genética , Mycobacterium tuberculosis/genética , Reacción en Cadena de la Polimerasa/métodos , Antituberculosos/farmacología , Antituberculosos/uso terapéutico , ARN Polimerasas Dirigidas por ADN/genética , Humanos , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/aislamiento & purificación , Perú , Valor Predictivo de las Pruebas , Rifampin/farmacología , Rifampin/uso terapéutico , Sensibilidad y Especificidad , Tuberculosis/tratamiento farmacológicoRESUMEN
A cross-sectional study was conducted in the Peruvian Amazon to test the hypothesis that a reservoir of asymptomatic malaria parasitemic patients would form the basis for continuing malaria endemicity in the region. Active surveillance yielded a Plasmodium spp. slide-positive prevalence of 4.2% (43 of 1,023) and a polymerase chain reaction (PCR)-positive prevalence of 17.6% (144 of 819). Plasmodium vivax prevalence was 2.9% and 14.2% while Plasmodium falciparum prevalence was 1.3% and 2.6% by microscopy and PCR, respectively. Approximately two-thirds of slide-positive and one-fourth of PCR-positive people were symptomatic. Anemia was associated with slide positivity (P < 0.001) and PCR positivity for P. falciparum (P = 0.003). Sensitivity of field microscopy and agreement between field and reference laboratory microscopists were low, arguing for using PCR for epidemiologic investigation and malaria control. While these data confirm recent findings from the Brazilian Amazon suggesting that sufficient numbers of asymptomatic malaria parasitemic patients are present to form a persistent reservoir for continuous reinfection within the Peruvian Amazon region, these results also indicate that clinical immunity in human populations can be driven in malaria-endemic regions that do not have high intensity malaria transmission.
Asunto(s)
Malaria/epidemiología , Vigilancia de la Población , Anemia/complicaciones , Anemia/epidemiología , Animales , Estudios Transversales , Demografía , Reservorios de Enfermedades , Humanos , Malaria/complicaciones , Malaria/diagnóstico , Malaria/parasitología , Oportunidad Relativa , Parasitemia , Perú/epidemiología , Plasmodium/aislamiento & purificación , PrevalenciaRESUMEN
A novel heminested IS6110 polymerase chain reaction (PCR) assay was evaluated as a tool for diagnosing tuberculosis in 222 children. In an analysis of 392 specimens (gastric aspirates, nasopharyngeal aspirates, and sputum samples), results of PCR were compared with those of 3 culture methods, acid-fast bacillus (AFB) staining, and clinical assessment by the Stegen-Toledo score. The sensitivity of PCR (67%) was comparable to that of the 3-culture method (71%) and was significantly higher than that of Löwenstein-Jensen culture (54%) or AFB stain (42%) for children with highly probable tuberculosis. PCR detection rates for culture-positive specimens were 100% for smear-positive samples and 76.7% for smear-negative samples. The specificity of PCR was 100% in control children. Compared with culture, PCR demonstrated a sensitivity of 90.4%, a positive predictive value of 89%, a specificity of 94%, and a negative predictive value of 95% (kappa=.85). With clinical assessment as the standard, PCR had a sensitivity of 71%, a positive predictive value of 92%, a specificity of 95%, and a negative predictive value of 79% (kappa=.67). PCR is a rapid and sensitive method for the early diagnosis of pediatric tuberculosis.