Detection and serotyping of lyophilized nonculturable pneumococcal isolates

One hundred fifty-two nonculturable lyophilized carriage pneumococcal isolates from a vaccine trial were subjected to PCR for serotyping, and 149 (98%) were successfully classified as vaccine or nonvaccine types, which were similar to viable isolates. The methodology will be useful for analysis of this and other studies where stored pneumococcal isolates fail to grow

Theoretical and Experimental Studies of Hydrogen Bonded Dihydroxybenzene Isomers Polyurethane Adhesive Material

Hydrogen bonding in polyurethane (PU) is imposed by molecular parameters. In this study, the effect of structural isomerism of certain monomers on hydrogen bonding of waterborne polyurethane (WBPU) was studied theoretically and experimentally. Two dihydroxybenzene (DHB)-based structural isomers such as catechol (CC) and hydroquinone (HQ), with different OH positions on the inner benzene core, had been used. Two series of WBPU dispersions were prepared using CC and HQ with defined contents. The binding energies between the catechol (CC)/hydroquinone (HQ) (respective OH group) and urethane/urea were calculated theoretically. By using a density functional theory (DFT) method, it was found that the largest binding energy between the urea and CC was higher than that of urea and HQ. The FT-IR analysis of synthesized polymer was also carried out to compare the results with the theoretical values. The CC-based polymers showed a stronger hydrogen bond both theoretically and experimentally than those for HQ-based polymers. The higher level of hydrogen bond was reflected in their properties of CC-based polymers. The adhesive strength, thermal stability, and hydrophobicity were higher for CC-based materials than those for HQ-based materials. The adhesive strength was increased 25% with the addition of 2.0 wt% CC content. This adhesive strength slightly deviated at a moderately high temperature of 80 °C

Detection and serotyping of lyophilized nonculturable pneumococcal isolates

One hundred fifty-two nonculturable lyophilized carriage pneumococcal isolates from a vaccine trial were subjected to PCR for serotyping, and 149 (98%) were successfully classified as vaccine or nonvaccine types, which were similar to viable isolates. The methodology will be useful for analysis of this and other studies where stored pneumococcal isolates fail to grow. Copyright © 2012, American Society for Microbiology. All Rights Reserved

Maternal and neonatal colonization in Bangladesh: Prevalences, etiologies and risk factors

Objective:To estimate the prevalence of maternal colonizers in South Asia and their potential to colonize the umbilicus, an important precondition causing neonatal sepsis.Study design:We conducted a cross-sectional study at a maternity center in Dhaka with 1219 pregnant women and a subset of 152 newborns from 15 January to 31 October 2011. During labor, study paramedics collected vaginal swabs for bacterial culture and rectal swabs for Group B Streptococcus (GBS) testing. Community health workers collected neonatal umbilical swabs. Log-binomial regression models were used to estimate risk ratios.Result:In all, 454 women (37.2%, 95% confidence interval (CI) 34.5 to 40.0%) were colonized. The most common organisms isolated were Staphylococcus aureus, Non-GBS and GBS. A total of 94 women (7.7%, 95% CI 6.2 to 9.2%) were colonized with GBS. The risk of GBS umbilical colonization was higher (RR=12.98, 95% CI 3.97 to 42.64) among newborns of mothers with GBS colonization.Conclusion:Newborns of mothers colonized with GBS are at higher risk of developing umbilical colonization. © 2013 Nature America, Inc

Early-onset neonatal sepsis in Dhaka, Bangladesh: Risk associated with maternal bacterial colonisation and chorioamnionitis

Objective: To estimate the risk of early-onset neonatal sepsis among newborns of mothers with chorioamnionitis and/or bacterial colonisation in Dhaka. Methods: We conducted a cohort study at a maternity centre following 600 mother-newborn pairs. Women with a positive bacterial vaginal culture or positive Group B streptococcus (GBS) rectal culture during labour were classified as colonised. Women with placental histopathology demonstrating signs of maternal or foetal inflammation were classified as having chorioamnionitis. Newborns were followed over the first 7 days of life. The primary outcome measure was physician or community health worker diagnosis of neonatal sepsis following modified World Health Organization Integrated Management of Childhood Illnesses criteria. Survival analysis was conducted with non-parametric, parametric and semiparametric models. Results: Of the 600 mother-newborn pairs, 12.8% of newborns were diagnosed with early-onset sepsis. Five hundred and forty-three women had both colonisation and chorioamnionitis data, 55.4% of mothers were non-exposed, 31.7% were only colonised and 12.9% had chorioamnionitis regardless of colonisation status. After adjusting for birthweight, sex, maternal characteristics and wealth, newborns of only colonised mothers developed sepsis 63% faster and had a 71% higher risk of developing sepsis than their non-exposed counterparts (RT = 0.37, 95% CI 0.14-1.03; RH = 1.71, 95% CI 1.00-2.94). Newborns of mothers with chorioamnionitis developed sepsis 74% faster and had a 111% higher risk of developing sepsis (RT = 0.26, 95% CI 0.07-0.94; RH = 2.11, 95% CI 1.06-4.21). Conclusions: Newborns born to mothers with colonisation or chorioamnionitis developed sepsis faster and were at higher risk of developing sepsis in Dhaka. © 2013 John Wiley & Sons Ltd

Detection of co-colonization with Streptococcus pneumoniae by algorithmic use of conventional and molecular methods

Detection of pneumococcal carriage by multiple co-colonizing serotypes is important in assessing the benefits of pneumococcal conjugate vaccine (PCV). Various methods differing in sensitivity, cost and technical complexity have been employed to detect multiple serotypes of pneumococcus in respiratory specimens. We have developed an algorithmic method to detect all known serotypes that preserves the relative abundance of specific serotypes by using Quellung-guided molecular techniques. The method involves culturing respiratory swabs followed by serotyping of 100 colonies by either capsular (10 colonies) or PCR (90 colonies) reactions on 96-well plates. The method was evaluated using 102 nasal swabs from children carrying pneumococcus. Multiple serotypes were detected in 22% of carriers, compared to 3% by World Health Organization (WHO)-recommended morphology-based selection of 1 to 3 colonies. Our method, with a processing cost of $87, could detect subdominant strains making up as low as 1% of the population. The method is affordable, practical, and capable of detecting all known serotypes without false positive reactions or change in the native distribution of multiple serotypes

Impact of introduction of the haemophilus influenzae type b conjugate vaccine into childhood immunization on meningitis in Bangladeshi infants

Objectives: Some Asian countries have been reluctant to adopt Haemophilus influenzae type b (Hib) conjugate vaccination because of uncertainty over disease burden. We assessed the impact of introduction of Hib conjugate vaccine into the Expanded Program on Immunization in Bangladesh on purulent and laboratory-confirmed H influenzae meningitis. Study design: Within a well-defined catchment area around 2 surveillance hospitals in Dhaka, Bangladesh, we compared the incidence of Hib meningitis confirmed by culture, latex agglutination, and polymerase chain reaction assay among infants 1 year before and 1 year after introduction of Hib conjugate vaccine. We adjusted the incidence rate for the proportion of children who sought care at the surveillance hospitals. Results: Among infants, the incidence of confirmed Hib meningitis decreased from 92-16 cases per 100 000 within 1 year of vaccine introduction (vaccine preventable incidence = 76; 95% CI 18, 135 per 100 000). The incidence of purulent meningitis decreased from 1659-1159 per 100 000 (vaccine preventable incidence = 500; 95% CI: 203, 799 per 100 000). During the same time period, there was no significant difference in the incidence of meningitis due to Streptococcus pneumoniae. Conclusions: Introduction of conjugate Hib conjugate vaccine into Bangladesh Expanded Program on Immunization markedly reduced the burden of Hib and purulent meningitis. Copyright © 2013 Mosby Inc. All rights reserved