Characterization of uropathogenic E. coli from various geographical locations in India.

Objectives: Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infection, accounting for more than 80% of cases worldwide. This study presents data on prevalent serotypes, resistance profiles, and colonization-aiding virulence characteristics of UPEC from different geographical regions in India. Methods: UPEC were serotyped through microtiter plate agglutination. Standard techniques were used to detect various virulence characteristics, i.e., biofilm formation (tissue culture plate method), siderophore production (screened on Chrome Azurol S agar and categorized with Csaky's and Arnow's methods), colicin release (agar overlay technique), gelatin hydrolysis (on gelatinase agar), and cell surface hydrophobicity (salt aggregation method). Antibiotic resistance profiles (against 20 antimicrobial agents) and extended-spectrum beta-lactamase (ESBL) were evaluated according to Clinical and Laboratory Standards Institute guidelines. Results: UPEC strains exhibited very high drug resistance rates to most of the commonly used antimicrobial agents; the highest resistance rates were observed for ampicillin (63.4%), nalidixic acid (63.4%), and cefotaxime (62.1%). High rates of multi-drug resistance (63.36%), ESBL-production (34.1%), and carbapenem-resistance (25.0%) were detected in UPEC strains from all geographical regions of India. Hydrophobicity (61.2%), biofilm production (62.5%), and siderophore production (67.7%) were the most common virulence characteristics of UPEC isolates. Co-expression of virulence characteristics was common (69.8%) in UPEC strains. Conclusion: UPEC strains with very high antimicrobial-resistance are in circulation in India, and have diverse serotypes and virulence characteristics.

Non-typhoidal Salmonella infections across India: emergence of a neglected group of enteric pathogens.

Objective: Non-typhoidal Salmonellae (NTS) are a neglected group of enteric pathogens whose prevalence is increasing at alarming rates across India. The disease burden is being underestimated because of a lack of effective surveillance of NTS infections in the Indian population. This study depicts the acquisition of NTS infection, and its persistence and spread through a diverse range of hosts, including humans and animals, and food and environmental sources. Methods: During the study period from 2016 to 2018, a total of 999 suspected NTS isolates were received from across India and were phenotypically and serologically characterized for the presence of NTS. Results: Of the 999 isolates, 539 (53.95%) were confirmed as NTS, consisting of 17 different NTS serovars. The majority were isolated from human samples (n = 319, 59.18%), followed by food products (n = 99, 18.37%), animals (n = 83, 15.4%) and the environment (n = 38, 7.05%). Some predominant serovars obtained included S. Typhimurium (n = 167, 30.98%), S. Lindenberg (n = 135, 25.05%), S. Enteritidis (n = 56, 10.39%), S. Weltevreden (n = 44, 8.16%), S. Choleraesuis (n = 41, 7.61%) and S. Mathura (n = 33, 6.12%). Conclusion: This study depicts the NTS disease burden across India, on the basis of the isolation of NTS serovars across diverse geographic locations. The emergence of newer or less common NTS serovars implicated in human infection poses a potential challenge to the healthcare system in India. Therefore, national and regional level surveillance is needed to implement effective control strategies and safeguard community health in India.

Serovar diversity of Salmonella among poultry.

Background & objectives: Salmonellosis due to the consumption of contaminated poultry products is a well-known public health concern, and assessing the distribution of Salmonella serovars among poultry becomes important for better prevention and control. The objective of the present study was to assess the distribution of Salmonella serovars among poultry. Methods: The isolates received at National Salmonella and Escherichia Centre during 2011-2016 were subjected to biochemical identification, followed by serological characterization to identify the Salmonella serovars, and the data were presented to exhibit the distribution of Salmonella serovars among poultry. Results: Salmonella was found to be present in poultry in all the regions included in the study. Salmonella Typhimurium, S. Gallinarum and S. Enteritidis were the most prevalent serovars accounting for 96.2 per cent of isolates. Salmonella was identified in poultry from all major egg-producing and egg-consuming States. Other serovars which were scantly identified included S. Infantis (2.7%), S. Montevideo (0.64%), S. Newport (0.26%) and S. Pullorum (0.13%). Interpretation & conclusions: Diverse distribution of Salmonella serovars in poultry in India, with known potential to infect human population and/or other poultry flocks, requires urgent nationwide stringent control measures.

Analysis of Salmonella enterica Serovar Typhi by Outer Membrane Protein (OMP) Profiling, Random Amplification of Polymorphic DNA (RAPD) and Pulsed Field Gel Electrophoresis (PFGE).

A number of countries, including developed countries, still have typhoid fever as a major problem resulting in frequent outbreaks. The importance of controlling spread of typhoid fever is well known and necessitates periodic studies to delineate epidemiological relationships. Although phage typing remains to be the preferred conventional method for characterisation of typhoid bacilli, it is of limited use due to prevalence of few predominant phage types in the country like India. Therefore, an effort has been made to assess three molecular methods [Outer Membrane Protein (OMP) Profiling, Random Amplification of Polymorphic DNA (RAPD) and Pulsed Field Gel Electrophoresis (PFGE)] for typing of Salmonella enterica serovar Typhi. 128 Salmonella enterica serovar Typhi isolates were identified using biotyping and serotyping followed by antimicrobial susceptibility testing. These isolates were further subjected to OMP analysis, RAPD and PFGE. PFGE (114 unique clusters) was found to be the most discriminatory method followed by RAPD (94 unique clusters) and OMP profiling (50 unique clusters). Multidrug resistant strains were well discriminated by all three methods used in the study. PFGE still remains the most preferred method for detailed epidemiological investigations. However, random amplification of polymorphic DNA and outer membrane protein profiling can also be considered for molecular discrimination of the isolates in the laboratories lacking high-end facilities.

WHO technical workshop on stability of reference materials for biological medicines and in vitro diagnostics, Geneva, Switzerland, 28-29 November 2005.

In November 2005, the World Health Organization convened an informal technical workshop on the stability of reference materials for biological medicines and in vitro diagnostics. The meeting was attended by experts from WHO collaborating centres in the area of biological standardization, national control laboratories, industries and other relevant organizations. The consultation group discussed current practices and approaches to predicting and monitoring the stability of biological reference materials. The group agreed to the need for establishing a working group (i) to continue dialogue on potential issues encompassing the principles, strategies and practicality for assuring the stability of WHO international reference standards for biological medicines and in vitro diagnostics and (ii) to develop more detailed guidance for assessment of the stability of WHO international biological reference materials.

Interference of thiomersal in biologicals during protein estimation.

In the present report thiomersal was detected as interfering substance in hepatitis B vaccines during the total protein estimation by Lowry's protein assay. The thiomersal at different concentrations of 0.005%, 0.0075%, 0.01%, 0.02%, 0.05% and 0.1% was found to reduce the Folin Ciocalteu's phenol reagent and produce colour development between 0.024 O.D to 1.023 O.D. values. Further, the thiomersal was shown to interfere between 34.55% to 52.73% with Folin Ciocalteu's phenol reagent, when 10 batches of different hepatitis B vaccines were subjected to estimation of total protein content by Lowry's protein assay.