RESUMO
At least eight species of Cryptosporidium can cause human infection and disease. A real-time PCR (qPCR) assay based on the 18S rRNA gene and utilizing a Scorpion probe was developed to detect all human-pathogenic Cryptosporidium without the usual need for nested amplification. Sensitivity of detection in stool samples was highest using a glass bead-based DNA extraction method (under 10(3) oocysts per stool sample). The assay was validated against 123 human stool specimens from Bangladesh and Tanzania, exhibited a sensitivity and specificity of >91% versus microscopy, and detected an additional eight microscopy-negative infections. Cryptosporidium parvum-specific and Cryptosporidium meleagridis-specific Scorpion qPCR assays that provided 100% accurate speciation compared with VspI RFLP analysis and sequencing were developed subsequently. These Scorpion probe qPCR assays are simpler to perform than existing nested PCR and RFLP methods for diagnosis and epidemiological investigation of cryptosporidiosis.
Assuntos
Criptosporidiose/parasitologia , Cryptosporidium/classificação , Cryptosporidium/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Animais , Sequência de Bases , Primers do DNA , DNA de Protozoário/análise , DNA Ribossômico/análise , DNA Ribossômico/genética , Fezes/parasitologia , Genes de RNAr , Humanos , RNA Ribossômico 18S/genética , Sensibilidade e EspecificidadeRESUMO
Transmission of Streptococcus pneumoniae between children and their parents was evaluated in 29 pairs from 25 families. The serotypes of 35 pneumococcal isolates from 18 (62.1%) of 29 child-parent pairs were identical. Of the 35 isolates, 23 showed intermediate resistance and 10 were fully resistant to penicillin G. PCR indicated that all 35 strains had at least one alteration in penicillin-binding protein genes pbp1a, pbp2x, and pbp2b and 33 strains had macrolide resistance genes mef(A) and/or erm(B). As a result, the PCR patterns of 16 of 18 pairs were identical. Molecular typing by pulsed-field gel electrophoresis showed that 12 pairs were indistinguishable, 3 pairs were closely related, 2 pairs were possibly related, and only one pair was different. Our data indicate the presence of a high rate of transmission of penicillin-resistant S. pneumoniae between children and their parents.