RESUMO
SETTING: The epidemiology of zoonotic tuberculosis (ZTB) in humans in Mexico is poorly known. OBJECTIVE: To identify isolates of Mycobacterium bovis in humans and cattle by polymerase chain reaction (PCR), and establish the clinical and epidemiological importance of ZTB in humans. DESIGN: From 1995 to 2009, 124 isolates from patients with TB and 60 isolates from cattle were analysed. PCR identification was performed using the oxy R gene, and the clinical and epidemiological aspects of ZTB in humans were investigated. RESULTS: PCR identified 93 M. bovis isolates: 35 (28%) from the 124 human isolates and 58 (97%) from the 60 cattle isolates. The sensitivity and specificity of the method were 100%. ZTB in the 35 patients presented as extra-pulmonary TB (EPTB) in 74%: 51% were children, 69% had malnutrition, 51% had consumed unpasteurised milk and 6% had contact with animals; 11% were relapses and 31% died. CONCLUSIONS: PCR using the oxy R gene is highly sensitive, specific and rapid for the identification of M. bois. ZTB is a serious public health problem, and presented as EPTB in children with malnutrition and those who had consumed unpasteurised milk. ZTB provokes relapses and a high mortality rate.
Assuntos
Proteínas de Bactérias/genética , Mycobacterium bovis/genética , Tuberculose Bovina/microbiologia , Zoonoses/microbiologia , Adulto , Idoso , Animais , Bovinos , Distribuição de Qui-Quadrado , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Desnutrição/mortalidade , México/epidemiologia , Pessoa de Meia-Idade , Leite/microbiologia , Epidemiologia Molecular , Mycobacterium bovis/classificação , Reação em Cadeia da Polimerase , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Tuberculose Bovina/diagnóstico , Tuberculose Bovina/mortalidade , Tuberculose Bovina/transmissão , Zoonoses/transmissãoRESUMO
SETTING: Cervical tuberculous lymphadenitis (CTBL) diagnosis is a critical problem due to the difficulty in culturing Mycobacterium tuberculosis. OBJECTIVE: To evaluate a nested polymerase chain reaction (nPCR) for the diagnosis of CTBL. DESIGN: Thirty-eight children initially diagnosed on the basis of clinical and laboratory criteria as suffering from chronic cervical lymphadenitis were included in the study. Forty-one cervical lymph node specimens were analysed by bacterial staining, culture, cytology or histopathology. The IS6110 DNA sequence of M. tuberculosis complex was amplified by nPCR. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and efficiency were determined for the assay. RESULTS: The sensitivity of nPCR was 96%, the specificity 93%, PPV 96%, NPV 93% and efficiency 95%. Among 25 patients with CTBL, six presented a 'definite' diagnosis (24%) according to established criteria; 10 were classified as 'highly probable' cases (40%) and nine presented a 'possible' diagnosis (36%). The sensitivity of nPCR was higher than the sensitivity of staining (15%), culture (26%) and cytology or histopathology (62.5%) (95%CI P < 0.05, chi(2) P < 0.001). CONCLUSION: The nPCR used is a highly sensitive, specific and efficient method for the diagnosis of CTBL among children.
Assuntos
Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Tuberculose dos Linfonodos/diagnóstico , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , México , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Infectious diseases caused by H. influenzae type b are considered preventable through vaccination with Hib conjugate vaccines. Some countries which follow Hib vaccination programs are close to eradication of the disease. In Mexico in particular, little epidemiological information is available. METHODS: In this study, 90 clinical strains of H. influenzae were obtained from Mexican children who were treated in four pediatric hospitals in Puebla City, and were diagnosed with invasive or localized infectious diseases. The strains were identified by standard bacteriological methods. Biotyping was done by Kilian criteria and serotyping by coagglutination. RESULTS: H. influenzae infections were found in children younger than 5 years of age, and 68.8% of the children were younger than 24 months. Sixty percent of the isolates belonged to serotype b, 31.1% were nontypeable, and 7.7% were considered non-type b. Serotype b was the most frequent isolate associated with invasive infectious diseases; however, nontypeable strains were isolated more frequently from children with otitis, sinusitis, conjunctivitis, and bronchial secretion. Non-type b serotypes were isolated from invasive and non-invasive infections in few cases. Biotypes I and IV were the most frequent isolates of H. influenzae. CONCLUSIONS: This study emphasizes the urgent need for an Hib-conjugated vaccine to achieve immunization in a pediatric population.
Assuntos
Técnicas de Tipagem Bacteriana , Haemophilus influenzae/isolamento & purificação , Adolescente , Criança , Pré-Escolar , Haemophilus influenzae/classificação , Humanos , México , Estudos Retrospectivos , SorotipagemRESUMO
Haemophilus influenzae has been recognized as one of the most important pathogen in the pediatric population younger than 5 years old. We analized some characteristics of the infectious diseases by Haemophilus influenzae in the pediatric group from 1985 to 1990 in two hospitals of Puebla city. From 321 children studies cases included for this work, fifty of those had infectious diseases by H. influenzae. Forty six percent of the patients developed meningitis, 22% otitis media, 12% sepsis, 10% pneumonia and 10% other infectious diseases. The majority of cases occurred in males but the difference was not statistically significant (p > 0.05). Eighty percent of diseases by H. influenzae occurred in infants younger than 24 months. The serovar b was the most frequent in invasive infections and nontypable strains were frequent in otitis media. The biovars I and IV were isolated from invasive infections. During this study two children died with meningitis and 3 patients had severe neurological damage. This finding suggests that is necessary to vaccine this population to prevent the morbilethality of infectious diseases by Haemophilus influenzae.