Jyotsna Agarwal

Pathogenomics of uropathogenic Escherichia coli

Subset of faecal E. coli that can enter, colonize urinary tract and cause infection are known as uropathogenic E. coli (UPEC). UPEC strains act as opportunistic intracellular pathogens taking advantage of host susceptibility using a diverse array of virulence factors. Presence of specific virulence associated genes on genomic/pathogenicity islands and involvement of horizontal gene transfer appears to account for evolution and diversity of UPEC. Recent success in large-scale genome sequencing and comparative genomics has helped in unravelling UPEC pathogenomics. Here we review recent findings regarding virulence characteristics of UPEC and mechanisms involved in pathogenesis of urinary tract infection.

Analysis of carbapenem-resistant Acinetobacter from a tertiary care setting in North India

Multidrug-resistant (MDR) Acinetobacter baumannii is a worldwide concern as cause of serious nosocomial infections. We analysed 140 non-duplicate Acinetobacter sp. isolates from hospitalised patients in a tertiary care centre; 87% were MDR and 20% (28/140) meropenem resistant. Metallo-β-lactamase was produced by 16 of these, detected by ethylene-diamine-tetra-acetic acid disc synergy test. AmpC β-lactamase and efflux pump were present in 17 and 4 of the meropenem-resistant Acinetobacter, respectively. 9/16 MBL-positive isolates carried genes for carbapenem resistance as shown by polymerase chain reaction.

Atypical bacterial pathogens in community-acquired pneumonia in children: a hospital-based study

A total of 243 children aged one month to five years with World Health Organization defined severe community acquired pneumonia were studied for the presence of atypical bacterial pathogens: 24 were found positive for mycoplasma infection. There was no significant association with any of the clinical, laboratory and radiological variables in children with pneumonia by the atypical pathogen.

Association of TNF-α -308G>A and TNF-β +252A>G genes polymorphisms with primary immune thrombocytopenia: a North Indian study.

Primary immune thrombocytopenia (ITP) is manifested by platelet autoantibodies that are not only responsible for platelet destruction by phagocytosis but also inhibit their production. Bleeding is the most common clinical manifestation of thrombocytopenia. ITP is a multifactorial disease in which both environmental and genetic factors have been implicated. It has been reported that several gene polymorphisms influence host susceptibility to ITP. This study was aimed to investigate the association of polymorphisms in tumor necrosis factor-alpha (TNF-&agr;) 308 G>A and TNF-&bgr; +252 A>G genes with primary ITP in Indian patients. Genotyping for the TNF-&agr; −308 G>A and TNF-&bgr; +252 A>G was performed in 80 ITP patients and 100 controls by polymerase chain reaction and restriction fragment length polymorphism. We found no significant difference in distribution of TNF-&agr; heterozygous variant genotype (GA) among patients and controls. Homozygous variant genotype (AA) was absent both in patients and controls. No statistical difference was observed in the distribution of heterozygous variant (AG) and homozygous variant (GG) genotypes of TNF-&bgr;, between patients and controls. Heterozygous (AG) genotype of TNF-&bgr; −308G>A was associated with persistent ITP. The study showed that heterozygous variant (AG) genotype of TNF-&bgr; was associated with persistent ITP, when compared with controls. We could not find any association of TNF-&agr; with susceptibility in developing ITP. Furthermore, no association was observed with respect to different categories of ITP. In addition, additive model showed two-fold increased susceptibility to ITP. We conclude that single nucleotide polymorphism in TNF-&bgr; +252 A>G gene may have impact on susceptibility to ITP.

Genotypic characteristics and biofilm formation among Escherichia coli isolates from Indian women with acute cystitis

BACKGROUND The purpose of present study was to characterize uropathogenic Escherichia coli (UPEC) associated with acute cystitis in Indian women. METHODS In this prospective descriptive study we investigated phylogenetic background and virulence genotypes for 15 genes by multiplex PCR and in vitro biofilm formation ability of 172 E. coli strains and explored possible association amongst them. RESULTS Most isolates (81, 47.1%) belonged to group B2 and A (50, 29.1%); few were from groups B1 (22, 12.7%) and D (19, 11.1%). The mean virulence scores of phylogroups A, B1, B2 and D were 3.3, 4.0, 4.6 and 4.9, respectively. We found higher prevalence of fimH, traT iutA, kpsMII, papG allele II and fyuA genes indicating putative role of adhesins, iron acquisition systems and protectins in causing bladder infection. Total 145 (84.3%) isolates produced biofilm; majority were weak biofilm producers and there was no significant difference in intensity and biofilm formation ability amongst various phylogroups or virulence scores. The phylogenetic distribution was different from western studies, including a lower prevalence of group B2 (dominant but not a majority), followed by group A, and some traditionally group B2-associated virulence genes were more prevalent in phylogroup A isolates. CONCLUSIONS Distribution of virulence genotypes and phylotypes can vary with geographical location and the isolates from western countries cannot be treated as prototypes for Asian cystitis isolates.

The antimicrobial effectiveness of 25% propolis extract in root canal irrigation of primary teeth

CONTEXT The choice of irrigating solution used in root canals of primary teeth is complicated by their complex morphology and paucity of associated literature. Propolis is a natural product that has gained interest in this context due to its antibacterial effectiveness against several endodontic pathogens. AIM The present study was undertaken to assess the potential of water-soluble 25% propolis extract against microorganisms present in root canals of primary teeth during endodontic procedures. SETTINGS AND DESIGN The child patients in the age group of 4-7 years with radiographic evidence of carious pulp exposure were included in the study. Definitive selection was done after gaining access into the pulp chamber and root canals of the selected teeth. The clinical and radiographic evidence of pathosis was ruled out for inclusion in the study. MATERIALS AND METHODS The selected teeth were divided into two groups randomly. In Group A 0.9% isotonic saline and in Group B 25% extract water-soluble propolis were used as irrigating solution, respectively. The bacterial samples were collected both pre- and post-irrigation and were transferred for microbial assay. STAISTISTICAL ANALYSIS: Wilcoxon matched signed rank test was used to compare the pre-and post-irrigation bacterial counts. Mann-Whitney test was used to compare the mean change (pre-post) in bacterial colony counts of groups in the study. RESULTS Antimicrobial effectiveness of 25% water-soluble extract of propolis in the root canals of primary teeth was confirmed in the present study. The reduction in the mean bacterial colony counts of all the isolated bacteria was noticed higher in Group B than Group A. CONCLUSION The results of the present study have confirmed that the antibacterial effectiveness of water-soluble extract of propolis in the root canals of primary teeth in vivo. Considering the low toxicity concerns and antibacterial effectiveness, water-soluble extract of 25% propolis can be advocated as a root canal irrigant in endodontic treatment of primary teeth.

Behavioral and Psychosocial Risk Factors Associated with First and Recurrent Cystitis in Indian Women: A Case-control Study.

Background: The risk factors for urinary tract infections (UTIs) from developed countries are not applicable to women from developing world. Objective: To analyze the behavioral practices and psychosocial aspects pertinent to women in our region and assess their association with acute first time or recurrent UTI. Materials and Methods: Sexually active premenopausal women with their first (145) and recurrent (77) cystitis with Escherichia coli as cases and women with no prior history of UTI as healthy controls (257) were enrolled at a tertiary care hospital in India, between June 2011 and February 2013. Questionnaire-based data was collected from each participant through a structured face-to-face interview. Results: Using univariate and multivariate regression models, independent risk factors for the first episode of cystitis when compared with healthy controls were (presented in odds ratios [ORs] with its 95% confidence interval [CI]): Anal sex (OR = 3.68, 95% CI = 1.59-8.52), time interval between last sexual intercourse and current episode of UTI was <5 days (OR = 2.27, 95% CI = 1.22-4.23), use of cloth during menstrual cycle (OR = 2.36, 95% CI = 1.31-4.26), >250 ml of tea consumption per day (OR = 4.73, 95% CI = 2.67-8.38), presence of vaginal infection (OR = 3.23, 95% CI = 1.85-5.62) and wiping back to front (OR = 2.52, 95% CI = 1.45-4.38). Along with the latter three, history of UTI in a first-degree female relative (OR = 10.88, 95% CI = 2.41-49.07), constipation (OR = 4.85, 95% CI = 1.97-11.92) and stress incontinence (OR = 2.45, 95% CI = 1.18-5.06) were additional independent risk factors for recurrent cystitis in comparison to healthy controls. Conclusion: Most of the risk factors for initial infection are potentially modifiable but sufficient to also pose risk for recurrence. Many of the findings reflect the cultural and ethnic practices in our country.

Role of special pathogenicity versus prevalence theory in pathogenesis of acute cystitis caused by Escherichia coli

Escherichia coli is the most common pathogen causing acute cystitis in sexually active women. Human faeces are generally considered the primary reservoir for infection and the faecal-perineal-urethral pathway is the accepted route of infection. Two theories have been proposed for the pathogenesis of acute cystitis: (1) special pathogenicity, where uropathogenic E. coli (UPEC) encoding special virulence factors causes infection; and (2) prevalence, wherein ordinary faecal E. coli causes infection by simple mass action. The aim of this study was to compare concurrent urinary E. coli isolates from women with acute cystitis with their own dominant faecal, vaginal E. coli isolates; thus, these patients served as their own control. E. coli isolates from 80 women were analysed by phylotyping, virulence profiling (for 15 putative virulence genes) and enterobacterial repetitive intergenic consensus (ERIC) PCR. A virulence score was calculated for each isolate based on the number of virulence genes detected. Four host ecological groups of E. coli were created on the basis of ERIC PCR: group UVF, where vaginal and faecal isolates yielded the infecting urine clone; group UV, where only vaginal isolates yielded the infecting urine clone; group UF, where faecal isolates yielded the infecting urine clone; and group U, where the infecting urine clone was distinct. In the majority of cases the infecting E. coli clone from urine was also the dominant faecal clone (56.3%; groups UVF and UF possessing high virulence scores of 4.6 and 3.9, respectively), indicating that both mechanisms play a role in pathogenesis. Non-dominant yet virulent faecal clones or an external source of E. coli seems a possibility in the UV group (13.7%, VF score 4.8). In 30% of patients (U group) the infecting urine clone was non-dominant and possessed a low virulence score (2.7); suggesting a possible role for host factors in establishing infection.

Observations on Citrobacter species from a tertiary care health center with special reference to multi-drug resistance and presence of CTX-M gene

BACKGROUND Citrobacter is an important nosocomial pathogen and its multi-drug resistant (MDR) isolates are increasingly being reported across the globe. They are known to produce extended spectrum beta lactamase (ESBL) and harbor CTX-M gene. OBJECTIVE The aim was to isolate Citrobacter sp. from clinical specimens, analyze their MDR status and look for the presence of CTX-M gene. MATERIALS AND METHODS In this prospective study, Citrobacter isolates positive for ESBL on screening, were confirmed by combined disc method along with minimum inhibitory concentration (MIC) for cefotaxime. In selected cefotaxime resistant isolates, multiplex polymerase chain reaction was done for blaCTX-M gene. RESULTS Of 146 Citrobacter sp. isolated, most (73%) were from admitted patients and hospital stay of >72 h and prior antibiotic intake were the most common associated factors. Maximum isolates were from pus (41.1%). Citrobacter freundii was the commonest species (49%) followed by Citrobacter koseri (28%); 79 were ESBL producers. Seventy were cefotaxime resistant as shown by MIC. blaCTX-M gene was detected in 15/40 of these isolates, all belonged to CTX-M group 1. CONCLUSION Overall incidence of Citrobacter in our setup is low, but they were mostly MDR, and ESBL production was high, which is a cause of concern. blaCTX-M gene detection is important because of its rapid transmission to other bacterial species.

Multidrug resistant Gram-negative bacilli from neonatal septicaemia at a tertiary care centre in North India: A phenotypic and genotypic study

for meropenem and colistin,[2] phenotypic tests for AmpC production (by cefoxitin disc,[3] disc antagonism test,[3] boronic acid inhibition test[4] and ceftazidime-imipenem antagonism test)[5] and test for presence of effl ux pump were performed.[6] Multiplex polymerase chain reaction (PCR) for CTX-M gene 1, 2, 8, 9 and 25[7] and blaIMP-1, blaIMP-2, blaVIM-1 and blaVIM-2 of carbapenemases genes were done.[6]