Comparison of pneumococcal colonization density among healthy children and children with respiratory symptoms using real time PCR (RT-PCR).

BACKGROUND: Nasopharyngeal colonization is considered a necessary step in the initiation of pneumococcal diseases. Real time PCR (RT-PCR) is an alternative approach for the identification and quantification of pneumococci directly from samples. OBJECTIVES: To compare pneumococcal detection rates using culture-based method versus RT-PCR direct detection and to quantify pneumococcal colonization in two study cohorts (healthy children and hospitalized children with respiratory symptoms) using quantitation through RT-PCR. METHODOLOGY: A total of 101 nasopharyngeal swabs (NPS) from healthy children and 183 NPSs from hospitalized children with respiratory symptoms were included in the study. None of the children were vaccinated. All children were between 2 months to 2 years. In parallel to routine culture and identification, a RT-PCR assay targeting the lytA gene was done. RESULTS: Considering all 284 samples tested, colonization rate by conventional culture was 41.2% (n = 117) while positive colonization using RT-PCR was 43.7% (n = 124). The colonization rate detected by RT-PCR in the healthy cohort was 33.7% (n = 34) and it was 49.2% (n = 90) in the hospitalized cohort. It was 37.6% (n = 38) and 43.2% (n = 79) for the two cohorts by culture. The mean Cq value for the healthy cohort is 29.61 (SD 2.85) and 28.93 (SD 3.62) for the hospitalized cohort. With the standard curve obtained from amplifying a dilution series of control DNA, the mean amount of genomic DNA copy numbers detected in children with respiratory symptoms was log10 7.49 (SD 1.07) while it was log10 7.30 (SD 0.23) in healthy children and the difference was not statistically significant. CONCLUSIONS: The overall colonization rate was higher when detected using RT-PCR compared to culture. However, it was lower in the healthy group when detected with RT-PCR compared to culture. Even though there was a higher detection of pneumococcal colonization density in children with respiratory symptoms, this was not significantly higher unlike many previous studies. Therefore, the use of RT-PCR to detect pneumococcal colonization needs further evaluation with careful analysis of interpretation and confounders.

Hormone receptor expression and Her/2neu amplification in breast carcinoma in a cohort of Sri Lankans.

OBJECTIVE: 1) To determine the profile of estrogen and, progesterone receptors (ER, PR) expression and Her/2neu amplification in carcinoma of breast of Sri Lankan women. 2) To determine their inter-relationships, and associations with age at diagnosis and histological grade. DESIGN: Retrospective analysis of data. SETTING: Department of Pathology, Faculty of Medicine, University of Peradeniya. MATERIALS: 124 samples of invasive ductal carcinoma of breast, stained for steroid receptors and Her/2neu amplification with immunohistochemistry. MEASUREMENTS: 1) Semiquantative scores of steroid receptors and Her/2neu amplification. 2) Correlations of ER, PR, Her/2neu amplification, age at diagnosis and histological grade. RESULTS: The prevalence of ER, PR and Her/2neu amplification were 53.2%, 50% and 14.6% respectively. The expression of ER and PR were significantly correlated (p < 0.001). and had a significant negative correlation with Her/2neu amplification (p0.003 each). Lower grade of the tumour was significantly related to the expression of ER (p0.000) and PR (p0.000) but not to Her/2neu amplification (p0.331). Age at diagnosis was significantly correlated to the expression of ER (p0.004), but not to PR (p0.365) or Her/2neu amplification (p0.456). CONCLUSION: Prevalence or ER, PR and Her/2neu amplification in carcinoma of breast among Sri Lankans is similar to that described internationally. The correlations of ER, PR, Her/2neu amplification, to each other, age at diagnosis and grade of tumour is as reported in other countries.