Samir K. Saha

Group B Streptococcus (GBS) is a leading cause of serious infection in very young infants. Robust incidence data from many geographic regions, including Latin America and Asia, are however lacking. A multicenter, hospital-based observational study was performed in Panama, Dominican Republic, Hong Kong and Bangladesh. All represented urban, tertiary referral hospitals, except Bangladesh. GBS cases (microbiological isolation from normally sterile sites in infants aged 0–89 days) were collected over 12 months. At 2.35 (95 % CI: 1.74–3.18) cases per 1000 live births, the incidence of early onset GBS disease (EOD) was highest in the Dominican Republic, compared with 0.76 (95 % CI: 0.41–1.39) in Hong Kong and 0.77 (95 % CI: 0.44–1.35) in Panama, while no cases were identified in Bangladesh. Over 90 % of EOD cases occurred on the first day of life, with case fatality ratios ranging from 6.7 % to 40 %, varying by center, age of onset and clinical presentation. Overall, 90 % of GBS (EOD and late onset disease) was due to serotypes Ia, Ib and III. The incidence rate of early onset GBS infection reported in Dominican Republic was not dissimilar from that described in the United States prior to screening and intrapartum antibiotic prophylaxis, while the incidence in Hong Kong was higher than previously reported in the Asian region. The failure to identify GBS cases in Bangladesh highlights a need to better understand the contribution of population, healthcare and surveillance practice to variation in reported incidence. Overall, the identified disease burden and serotype distribution support the need for effective prevention methods in these populations, and the need for community based surveillance studies in rural areas where access to healthcare may be challenging.

A total of 1,059 Salmonella enterica serovar Typhi were isolated from blood samples during January 2006 to October 2007 from urban rural facilities in Dhaka, Bangladesh, of which 980 (92.5%) isolates were nalidixic acid resistant. The minimum inhibitory concentrations (MIC) of ciprofloxacin (CIP) were determined for 127 nalidixic acid resistant Salmonella enterica serovar Typhi (NARST) strains (every fifth) isolated during 2006. Nine isolates were found to be resistant against CIP (3%) with high MIC (12 - >32 ?g/mL). Only four isolates were found to be sensitive (MIC <0.125 ?g/mL), whereas most of the isolates (N=113) showed reduced susceptibility (MIC 0.125 – 2 ?g/mL) to CIP. All these isolates were subjected to molecular typing by multiplex PCR on VNTR (variable number tandem repeats) loci, which revealed eight different VNTR patterns. Almost all CIP resistant strains had similar genetic organization, identical to the most common VNTR type. Restriction fragment length polymorphism (RFLP) analysis of the gyrA gene revealed point mutations at Ser-83 and Asp- 87 in all CIP resistant strains. DOI: http://dx.doi.org/10.3329/bjm.v28i1.11802 Bangladesh J Microbiol, Volume 28, Number 1, June 2011, pp 7-11

Isolation of Streptococcus pneumoniae is jeopardized by low sensitivity of blood culture, autolysis and contamination with fast-growing organism(s). We performed an immunochromatographic (ICT) test for S. pneumoniae on chocolatized blood culture bottles and also sub-cultured contaminated bottles on a selective medium, thus identifying an additional eight and three cases, respectively, and improving the detection of pneumococcus by 23% (48% vs. 59%). Prescreening of culture bottles in a blinded fashion could rationalize the use of ICT with ∼99% accuracy. These two approaches can aid microbiology laboratories in resource-poor countries to substantially improve rates of detection of S. pneumoniae.

Background. Evaluation of the long-term impact of pneumococcal meningitis on surviving children and their families is critical to fully comprehending

Background. Vaccines offer the prospect of primary disease prevention of pneumococcal disease in childhood. For introduction of such vaccines in deve

The reason for lack of data on burden of Haemophilus influenzae type b (Hib) in developing countries was mainly failure of detection of this fastidious organism in laboratories. Use of isovitalex (IVX) was suggested as an essential supplement for growing this organism. This study was carried out to investigate the impact of IVX supplementation to chocolate agar for detection of Hib. Chocolate agar with and without supplementation of IVX was prepared. Clinical samples as well as reference strains of Hib were simultaneously cultured on both the media. H. influenzae isolates (N=194) were simultaneously grown on chocolate agar (CA) with and without isovitalex (IVX). Average colony size of H. influenzae on CA with IVX (CA-IVX) was larger only by 0.10 cm (range 0.05 to 0.16 cm) compared to CA alone. Addition of IVX to CA increased the cost of media by 2.1-fold. Isovitalex is not essential for the isolation and growth of H. influenzae almost halving the cost.

AIM: To elucidate the age-distribution of anti-hepatitis A virus (HAV) seroprevalence across different socioeconomic status (SES) categories in Bangladesh which, despite scarce data, is generally deemed to have high endemicity.

PCR-based serotyping of Streptococcus pneumoniae has been proposed as a simpler approach than conventional methods, but has not been applied to strains in Asia where serotypes are diverse and different from other part of the world. Furthermore, PCR has not been used to determine serotype distribution in culture-negative meningitis cases. Thirty six serotype-specific primers, 7 newly designed and 29 previously published, were arranged in 7 multiplex PCR sets, each in new hierarchies designed for overall serotype distribution in Bangladesh, and specifically for meningitis and non-meningitis isolates. Culture-negative CSF specimens were then tested directly for serotype-specific sequences using the meningitis-specific set of primers. PCR-based serotyping of 367 strains of 56 known serotypes showed 100% concordance with quellung reaction test. The first 7 multiplex reactions revealed the serotype of 40% of all, and 31% and 48% non-meningitis and meningitis isolates, respectively. By redesigning the multiplex scheme specifically for non-meningitis or meningitis, the quellung reaction of 43% and 48% of respective isolates could be identified. Direct examination of 127 culture-negative CSF specimens, using the meningitis-specific set of primers, yielded serotype for 51 additional cases. This PCR approach, could improve ascertainment of pneumococcal serotype distributions, especially for meningitis in settings with high prior use of antibiotics.

Multidrug resistance (MDR), specifically to ampicillin and chloramphenicol, has complicated the treatment of Haemophilus influenzae type b (Hib) meningitis. This is worsened by use of prior antibiotics, which limits identification of the causative agent by culture and increases reliance on antigen detection. We aimed to develop a PCR assay for detecting the family of Haemophilus integrating and conjugative elements (ICEs) represented by ICEHin1056 among antibiotic resistant Hib, and then apply this directly to CSF to diagnose Hib meningitis and predict organism susceptibility, irrespective of culture results. Primers specific for orf 51 of ICEHin1056 were designed and multiplexed with Bex primers, specific for H. influenzae, and tested on culture positive and negative cases. Of 73 Hib isolates, orf 51 PCR amplicons, predicting the presence of ICEs, were found in all 33 MDR isolates while only in 1 of 33 sensitive strains. The remaining 7 ampicillin susceptible, chloramphenicol and tetracycline resistant strains did not produce a PCR product to orf 51. PCR amplification from CSF specimens of these culture positive cases produced identical results with 100% and 97% positive and negative predictive values, respectively. Multiplex PCR to detect Bex and orf 51 identified another 16 MDR Hib cases among 81 culture-negative CSF samples. Direct PCR for orf 51 in CSF identified resistance pattern of 51% more Hib strains than culture alone (110 versus 73). The ability to detect MDR, in culture negative Hib meningitis cases has significant implications for better directing antibiotic treatment of meningitis cases and thus for preventing disability and death.

Haemophilus influenzae type b (Hib) diseases are responsible for an estimated 400,000 childhood deaths, mostly in developing countries. To determine the value of the Wellcogen quantitative latex agglutination test (LA) in urine for the diagnosis of Hib pneumonia and meningitis. Healthy and sick children aged or=1:8 dilutions. The Wellcogen LA test for Hib using boiled and non-concentrated urine is more sensitive than blood culture alone and is highly specific.