Added value of IP-10 as a read-out of <em>Mycobacterium tuberculosis</em>:Specific immunity in young children

We have explored the added value of interferon-γ (IFNγ)–inducible protein 10 as a read-out of Mycobacterium tuberculosis–specific immunity in young Indian children, where the sensitivity of the IFNγ release assays for tuberculosis is poor. Reduced frequency of indeterminate results and an increased sensitivity for tuberculosis suggest a potential for fewer missed cases with a combined IFNγ/inducible protein 10 read-out in a 4th generation IFNγ release assays

Novel transcriptional signatures for sputum-independent diagnostics of tuberculosis in children

Pediatric tuberculosis (TB) is challenging to diagnose, confirmed by growth of Mycobacterium tuberculosis at best in 40% of cases. The WHO has assigned high priority to the development of non-sputum diagnostic tools. We therefore sought to identify transcriptional signatures in whole blood of Indian children, capable of discriminating intra-thoracic TB disease from other symptomatic illnesses. We investigated the expression of 198 genes in a training set, comprising 47 TB cases (19 definite/28 probable) and 36 asymptomatic household controls, and identified a 7- and a 10-transcript signature, both including NOD2, GBP5, IFITM1/3, KIF1B and TNIP1. The discriminatory abilities of the signatures were evaluated in a test set comprising 24 TB cases (17 definite/7 probable) and 26 symptomatic non-TB cases. In separating TB-cases from symptomatic non-TB cases, both signatures provided an AUC of 0.94 (95%CI, 0.88–1.00), a sensitivity of 91.7% (95%CI, 71.5–98.5) regardless of culture status, and 100% sensitivity for definite TB. The 7-transcript signature provided a specificity of 80.8% (95%CI, 60.0–92.7), and the 10-transcript signature a specificity of 88.5% (95%CI, 68.7–96.9%). Although warranting exploration and validation in other populations, our findings are promising and potentially relevant for future non-sputum based POC diagnostic tools for pediatric TB.publishedVersio

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Significant association of the dupA gene of Helicobacter pylori with duodenal ulcer development in a South-east Indian population

A novel virulence factor, duodenal ulcer-promoting gene A (dupA), in Helicobacter pylori has been found to be associated with disease in certain populations but not in others. This study analysed a South-east Indian population as part of the debate about the relevance of dupA for the prediction of clinical outcomes. A total of 140 H. pylori strains isolated from duodenal ulcer (DU) (n=83) and non-ulcer dyspepsia (NUD) patients (n=57) were screened by PCR and dot-blot hybridization to determine the presence of the ORFs jhp0917 and jhp0918. Part of jhp0917-jhp0918 was sequenced to search for the C/T insertion that characterizes dupA and the levels of dupA transcripts were also assessed. The PCR and dot-blot results indicated the presence of jhp0917 and jhp0918 in 37.3% (31/83) and 12.2% (7/57) of H. pylori strains isolated from DU and NUD patients, respectively. Sequencing analysis showed insertion of a C at nt 1386 in the 3' region of jhp0917, forming the dupA gene in 35 strains. RT-PCR analysis detected the dupA transcript in 28 of these 35 strains. The expression level of the dupA transcript varied from strain to strain, as shown by real-time PCR. The results demonstrated that analysis based on PCR only for dupA may produce an erroneous interpretation. The prevalence of dupA was significantly greater among strains isolated from patients with DU than from patients with NUD in this population (P=0.001, odds ratio=4.26, confidence interval=1.60-11.74). Based on these findings, dupA can be considered a biomarker for DU patients in India. The reported discrepancies for this putative virulence marker in different populations may be due to the genome plasticity of H. pylori

Nasal Carriage and Antimicrobial Susceptibility of Staphylococcus aureus in healthy preschool children in Ujjain, India

<p>Abstract</p> <p>Background</p> <p>There is increasing evidence that community acquired <it>S. aureus </it>infections are spreading among healthy children. Nasal colonization with <it>S. aureus </it>plays pivotal role in the increasing prevalence of resistant community acquired <it>S. aureus </it>infections worldwide. A regular surveillance system is important in ensuring quality of patient care. The aim of the study was to assess the prevalence of and the factors associated with nasal carriage of <it>S. aureus </it>and its antibiotic sensitivity pattern among healthy children in Ujjain, India.</p> <p>Methods</p> <p>A prospective study was done in paediatric outpatient clinics of R.D. Gardi medical college Ujjain, India. Healthy children from 1 month to 59 months of age were included. Information on previously known risk factors for nasal colonization was collected using a pre-tested questionnaire. Swabs from anterior nares were collected and transported in Amies transport media with charcoal and cultured on 5% sheep blood agar. Antibiotic sensitivity tests were performed using Kirby Bauer's disc diffusion method according to performance standards of Clinical and Laboratory Standard Institute guidelines.</p> <p>Results</p> <p>Of the 1,562 children from 1-month up-to five years of age included in the study 98 children tested positive for nasal carriage of <it>S. aureus</it>. The prevalence of nasal carriage of <it>S. aureus </it>was 6.3% (95% CI 5.1-7.5) out of which 16.3% (95% CI 8.9-23.8) were methicillin-resistant <it>S. aureus </it>(MRSA). The factors associated with nasal carriage were "child attending preschool" (OR 4.26, 95% CI 2.25-8.03; <it>P </it>= 0.007) or "school" (OR 3.02, 95% CI 1.27-7.18; <it>P </it>< 0.001) and "family size more than 10 members" (OR 2.76 95% CI 1.06-7.15; <it>P </it>= 0.03). The sensitivity pattern of isolated <it>S. aureus </it>showed resistance to commonly used oral antibiotics while resistance to glycopeptides was not noted.</p> <p>Conclusions</p> <p>We found a relatively low rate of nasal carriage of <it>S. aureus </it>in children below five years when compared to children of older age groups in India. Yet, prevalence of MRSA was relatively high.</p

Frequency and factors associated with carriage of multi-drug resistant commensal Escherichia coli among women attending antenatal clinics in Central India

BACKGROUND: Commensal Escherichia coli are a prominent reservoir of genes coding for antibiotic resistance and also responsible for endogenous infections in pregnant women. We studied the factors in pregnant women associated with carriage of multi-drug resistant (MDR) E. coli and genetic determinants of antibiotic resistance in them. METHODS: Women attending to Obstetric and Gynaecology department outpatient clinics for routine antenatal check-up were administered a questionnaire. Peri-anal swabs were collected for culture isolation and identification of E.coil. Antibiotic sensitivity was done using the Kirby-Bauer disc diffusion method as recommended by the CLSI guidelines. MICs for quinolones and third generation cephalosporins were done using the agar dilution method. Genes coding for production of beta lactamses and for the quinolone resistance determinant were screened by polymerase chain reaction. Rep-PCR was done on MDR isolates for detecting possible genetic similarity. Multiple logistic regression models were used to determine the independent factors associated with carriage of MDR isolates. RESULTS: A total of 710 isolates of E. coli from 710 women (mean age 26 years) were included in the study. Resistance to at least one antibiotic tested was detected in 94% of the E. coli isolates. A total of 109 isolates were ESBL producing and 35 isolates were MDR. In the MDR isolates MIC50 and MIC90 for quinolones and third generation cephalosporins were high for those isolates that carried blaTEM gene (26 isolates) and blaCTX-M gene (24 isolates). Both blaTEM and blaCTX-M genes were detected in 19 isolates. The commonest Plasmid Mediated Quinolone Resistance (PMQR) gene identified was aac(6')-Ib-cr (n = 23/25). All isolates carrying the PMQR genes were also positive for blaCTX-M and blaTEM gene. Mutations in gyr A and par C genes were present in all 35 MDR isolates. The statistically significant risk factors for carriage of MDR E. coli were graduate or post-graduate education, a self-employed status, a family size of more than 10 members, antibiotic usage in last four weeks, and history of hospitalization in the last four weeks. CONCLUSIONS: The presence of genes coding for extended spectrum of beta lactamases and plasmid mediated quinolone resistance in commensal E. coli is disconcerting. The study provides strong basis good antibiotic stewardship

Genotyping of Methicillin-Resistant Staphylococcus aureus Strains from Two Hospitals in Bangalore, South India

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in India, and up to 70% methicillin resistance has been reported from hospitals in various parts of India. Hospitals use phenotyping for the most part, and molecular genotyping is not done. Here we report on the genotyping of 82 single-patient isolates from two hospitals in Bangalore, South India, for the first time. Most of the strains possessed type III or IIIA staphylococcal cassette chromosome (SCCmec) cassettes, and we did not detect strains with type I, IA, or II cassettes. Most isolates also contained the type III cassette chromosome recombinase (ccr) AB region. Multilocus sequence typing (MLST) and staphylococcal protein A (spa) typing of a selected number of isolates have been carried out. Although most isolates that were chosen for MLST and spa typing had the same patterns, they were quite diverse in their pulsed-field gel electrophoresis (PFGE) patterns. PFGE, MLST, and spa typing of the Indian strains revealed that they are related to the previously described Hungarian and Brazilian clones

Antibiotic Resistance Characterization of Environmental E. coli Isolated from River Mula-Mutha, Pune District, India

In the current study, ceftazidime- and ciprofloxacin-resistant&mdash;or dual drug-resistant (DDR)&mdash;E. coli were isolated from river Mula-Mutha, which flows through rural Pune district and Pune city. The DDR E. coli were further examined for antibiotic resistance to six additional antibiotics. The study also included detection of genes responsible for ceftazidime and ciprofloxacin resistance and vectors for horizontal gene transfer. Twenty-eight percent of the identified DDR E. coli were resistant to more than six antibiotics, with 12% being resistant to all eight antibiotics tested. Quinolone resistance was determined through the detection of qnrA, qnrB, qnrS and oqxA genes, whereas cephalosporin resistance was confirmed through detection of TEM, CTX-M-15, CTX-M-27 and SHV genes. Out of 219 DDR E. coli, 8.2% were qnrS positive and 0.4% were qnrB positive. Percentage of isolates positive for the TEM, CTX-M-15 and CTX-M-27 genes were 32%, 46% and 0.9%, respectively. None of the DDR E. coli tested carried the qnrA, SHV and oqxA genes. Percentage of DDR E. coli carrying Class 1 and 2 integrons (mobile genetic elements) were 47% and 8%, respectively. The results showed that antibiotic resistance genes (ARGs) and integrons were present in the E. coli isolated from the river at points adjoining and downstream of Pune city