Cross-country transport and isolation and identification of Streptococcus pneumoniae by use of alternate sources of blood supplemented media among laboratories in India

Background: The isolation of S. pneumoniae (Sp) depends on specimen integrity / transport, media and expertise. The non-availability of sheep blood agar poses a challenge in identification of colonial morphology and identification in India. Methods: Laboratories processed swabs containing either pure Sp or Sp in mixed cultures with a second (confounding) bacterium shipped across the country in cold conditions. Duplicate set of swabs was shipped back to the central laboratory to assess the impact of shipping on culture viability. The identical swab was cultured on sheep, human blood and one additional agar plate used in the laboratory. Results: 46/60(77%) of cultures containing only Sp were correctly identified. In specimens where Sp was present in mixed culture, the proportion of isolates in which Sp was correctly identified varied, with most variability attributed to the particular confounding organism rather than the media. There was no discernible impact of temperature-controlled (4-6°C) transport on the isolation of Sp from culture swabs. Conclusions: The study clearly elucidates the ability of laboratories for isolation of S. pneumoniae on human blood agar in resource limited settings. The results highlight the difficulties inherent in correctly identifying pathogens in mixed cultures in needs improvement using standardized tests across the study centers. The study also reaffirms the ability to transport biological specimens over long geographical distances without loss.

Effect of enamel preparations on fracture resistance of composite resin buildup of fractures involving dentine in anterior bovine teeth: an in vitro study.

Sixty bovine teeth with simulated mesio-incisal angle fracture were randomly and equally divided in one untreated (control) group and three experimental groups (Bevel, Chamfer and newly introduced Stair-step Chamfer preparation group) to evaluate the effect of enamel preparations on the fracture resistance of composite resin. Post restoration, fracture mechanics approach was used to quantify the failure of composite resins in testing the samples in Instron testing machine. Mean peak failure load (Newton) of composite amongst experimental groups was observed in the order; Chamfer (326.09 +/- 72.73), Stair-step chamfer (315.21 +/- 81.77) and Bevel (253.83 +/- 67.38). Results of the One-Way ANOVA revealed significant difference in the mean peak failure load values of the four different groups. (P<0.001) Scheffe's Post-Hoc comparison test (Subset for alpha = 0.05) revealed that there was no significant difference in the mean peak failure load values of the bevel, stair-step chamfer and chamfer preparation when considered together, but the mean peak values of control group (605.22 +/- 48.96) were observed significantly higher. Failure mode evaluation revealed, majority of failures occurred as cohesive and mixed type for all the experimental groups. Adhesive type failure was observed maximum (33%) in the bevel group. Stair-step chamfer preparation showed greatest potential for application and use as it no only demonstrated comparable values to Chamfer preparation ['t' value (0.39) (P > 0.05)] but also involved sacrificing less amount of tooth structure adjacent to fractured edge.

Surface protein changes in goat spermatozoa during capacitation.

Polypeptides of goat sperm surface before and after capacitation were examined by radiolabelling and immunologically using polyclonal antisera. Radioiodination revealed five protein bands having mol wt of 14.8, 72.4, 81, 100 and 128 kDa in uncapacitated ejaculated spermatozoa and only three bands of 23.4, 27 and 72.4 KDa in capacitated spermatozoa. The protein band with mol wt 72.4 kDa was only feebly iodinated in uncapacitated sperm surface but in capacitated spermatozoa it was heavily labelled. Western blot analysis of detergent-extracted proteins using gamma-globulin fraction of antisera raised against purified goat sperm plasma membrane revealed six antigens (17.8, 29.1, 33.4, 45.6, 85.1, 123.2 kDa) in uncapacitated spermatozoa, four (26, 32.1, 40.1, 45.6 kDa) in capacitated spermatozoa and only one (45.6 kDa) in acrosome-reacted spermatozoa. High mol wt proteins were more numerous on the surface of uncapacitated spermatozoa while the capacitated spermatozoa had relatively low mol wt proteins. An apparent effect of capacitation is the metabolism and reorganisation of proteins on goat sperm surface. Polypeptides on capacitated sperm surface revealed through radiolabelling and polyclonal antisera may have a likely receptor(s) role in the recognition and binding to homologous zona pellucida during fertilization.

Hepatitis B virus infection and its transmission in preschool children.

In the present study, 2.5% of 367 preschool children has HBsAg positivity. Of 11 mothers who were HBsAg positive during the third trimester of pregnancy, 4 had babies (36.4%) who developed HBsAg positivity by 2.5-3 months of age (vertical transmission). Two babies born of HBsAg negative mothers, with history of jaundice during first trimester, were HBsAg negative. All the relatives of HBsAg positive cases screened were negative for HBsAg.