Diagnostic performance of the Luminex xTAG gastrointestinal pathogens panel to detect rotavirus in Ghanaian children with and without diarrhoea.

BACKGROUND: Rotavirus is one of the leading causes of childhood diarrhoea worldwide. The highest disease burden is seen in resource-constrained settings of sub-Saharan Africa. Recently, commercial multiplex PCR panels proved their accuracy to diagnose infectious gastroenteritis in Europe and the USA. However, data on their performance using samples from tropical regions in general and to detect rotavirus in particular remains scant. We aimed to analyse the diagnostic performance of the Luminex xTAG gastrointestinal pathogens panel, a multiplex PCR, to detect rotavirus in stool samples from Ghanaian children. METHODS: A total of 682 stool samples were collected in the Ashanti region of Ghana between 2007 and 2008. Of these, 341 were from cases (children with diarrhoea), and another 341 from controls (children without diarrhoea). All samples were analysed using the Luminex xTAG assay and compared to a rotavirus quantitative reverse-transcription PCR (reference assay). Rotavirus reference assay positive samples were P and G genotyped by sequencing the rotavirus VP4 and VP7 genes. RESULTS: Overall agreement between the Luminex xTAG and the reference assay was excellent (kappa 0.93). The sensitivity and specificity was 88.2 % (95 % confidence interval [CI] 78.2-94.1) and 100 % (95 % CI 99.2-100), respectively. Of 76 rotavirus reference assay positive samples, 64 were successfully genotyped and the Luminex xTAG assay was able to detect all rotavirus genotypes present in the study. CONCLUSION: The Luminex xTAG assay proved a sensitive and highly specific tool to detect rotavirus and may aid clinicians and public health authorities in the diagnosis and surveillance of rotavirus.

Application of a multiplex PCR assay for the detection of gastrointestinal pathogens in a rural African setting.

BACKGROUND: Despite high morbidity and mortality, the laboratory diagnosis of gastrointestinal infections is largely neglected in tropical African settings. This study aims to apply the Luminex multiplex PCR assay for the diagnosis of gastrointestinal pathogens in rural Ghana to evaluate its usefulness as a routine method. METHODS: A case-control study was conducted at the Agogo Presbyterian Hospital in Ghana. Stool samples were collected from children below 6 years of age with (cases) and without (controls) diarrhoea. Samples were screened for 15 different diarrhoeal pathogens by the Luminex xTAG GPP assay and associations between diarrhoea and gastrointestinal infections and fractions attributable to diarrhea (AF) were determined. RESULTS: The Luminex PCR assay identified organisms in 96.6% (n = 428) of 443 cases and in 92.5% (n = 221) of 239 selected controls. A mean of 2.5 (standard deviation [SD]: ± 1.3) and 2.3 (SD: ± 1.3) organisms per sample were detected in cases and controls respectively. An association with diarrhoea was found for rotavirus (adjusted odds ratio [aOR] = 7.2; 95% confidence interval [CI]: 2.9-18.1), norovirus (aOR = 2.7; 95% CI: 1.4-5.3) and Shigella spp. (aOR = 1.7; 95% CI: 1.2-2.4) with respective AFs of 12.5% (95% CI: 9.6-15.3), 7.9% (95% CI: 3.8-11.7) and 16.9% (95% CI: 6.9-25.9). CONCLUSION: The high proportion of pathogen-positive stool samples with a high number of co-infections in cases and controls suggests a substantial amount of transient or colonizing microorganisms for which treatment is not necessarily implicated. The use of sequential diagnostic algorithms with pathogen specific or quantitative PCRs might be most appropriate for diagnosing gastrointestinal infections.

High diversity of human parechovirus including novel types in stool samples from Ghanaian children.

BACKGROUND: Little is known on human parechovirus (HPeV) infections in Africa. OBJECTIVES: We aimed to determine the prevalence, genetic diversity, and association with diarrhea of HPeV in Ghanaian children. STUDY DESIGN: A total of 682 stool samples from a pediatric case-control study on causes of diarrhea collected in 2007-2008 were used. Laboratory analysis included HPeV real-time RT-PCR and sequencing partial viral protein (VP) 1 gene region of HPeV. In addition, data on co-infections using the xTAG Gastrointestinal Pathogen Panel were available. RESULTS: Overall, a prevalence of 24% was found and 14 different HPeV types were detected. Phylogenetic analysis of the VP1 region indicated a novel type tentatively designated as HPeV-18. No association with diarrhea was found (OR=0.8; 95% CI: 0.5-1.1), and HPeV viral concentrations were not different among cases and controls. No seasonal pattern was observed. HPeV-positive cases displayed a slightly higher chance of co-infections. CONCLUSIONS: A high prevalence and genetic diversity of HPeV including novel types was found by sequencing partial VP 1 region. HPeV was not associated with diarrheal disease in this pediatric population and the high number of co-infection suggests transient colonization without clinical relevance.