Efficacy of an in-house polymerase chain reaction assay for rapid diagnosis of Mycobacterium tuberculosis in patients with tubercular lymphadenitis: Comparison with fine needle aspiration cytology and conventional techniques.

Introduction: Tubercular lymphadenitis (TB-L) is the most common manifestation of extrapulmonary tuberculosis. Excisional biopsy with histopathological examination, Ziehl-Neelsen staining (ZNS) and culture and fine needle aspiration (FNA) cytology, although useful in the diagnosis of TB-L, cannot diagnose a substantial proportion of cases. We investigated the role of an in-house polymerase chain reaction (PCR) assay targeting the IS6110 gene from the FNA material in the diagnosis of the disease. Materials and Methods: The clinical profile of 150 patients with lymphadenopathy was noted and the fine needle aspirate was collected. After cytological processing, ZNS and culture on Lowenstein-Jensen media, mycobacterial DNA was isolated from the residual aspirate material and IS6110 gene PCR was performed. Results of cytology, ZNS, culture and IS6110 gene PCR were compared. Results: There were 49 confirmed patients of TB-L based on laboratory parameters (either culture isolation of Mycobacterium tuberculosis or any two of cytology, ZNS, PCR positive) and clinical response to therapy. Sensitivity and specificity of FNA was 89.8% and 96%, of ZNS was 40.8% and 99%, of culture was 40.8% and 100% and of IS6110 gene PCR test was 100% and 92.1%. Conclusion: IS6110 PCR can be considered a valuable adjunct to cytology, ZNS and culture techniques in the diagnosis of TB-L.

Pediatric urinary tract infections in a tertiary care center from north India.

Background & objectives: Paediatric urinary tract infections (UTI) are associated with high morbidity and long term complications like renal scarring, hypertension, and chronic renal failure. A cause of occult febrile illness, they often remain undiagnosed. We studied the clinical and microbiologic profile and antibiotic resistance profile of such infections in paediatric UTI patients at our center. Methods: Clean catch mid-stream urine samples for culture were received from 1974 children aged < 12 yr over a period of 6 months. Quantitative wet mount microscopy and semiquantitative culture on cysteine lactose electrolyte deficient medium were done to diagnose UTI. Isolates were identified by standard biochemical tests and antimicrobial sensitivity was determined. Clinical details including risk factors and underlying illness were noted. Results: Significant bacteriuria was found in 558 children (28.3%). Male gender (25.6%), age < 1 yr (77.5%), vesicoureteric reflux disease (VUR) (19.9%) and posterior urethral valve (PUV) (27.6%) were common risk factors in children suffering from UTI. Pyuria was detected in 53.6 per cent of infections. Common uropathogens isolated were Escherichia coli (47.1%), Klebsiella spp. (15.6%), Enterococcus fecalis (8.7%), members of tribe Proteae (5.9%), Pseudomonas aeruginosa (5.9%) and Candida spp. (5.5%). Against lactose fermenting Enterobacteriaceae, in-vitro resistance was least against amikacin (32.5%), nitrofurantoin (26.7%) and imipenem (3.7%). Among enterococci, vancomycin resistant enterococci constituted 12 per cent of the strains. 93.4 per cent of the UTI detected was nosocomial. Interpretation & conclusion: Paediatric UTI was common in children with male gender, age < 1 yr, and in children suffering from VUR and PUV. Spectrum of pathogens causing paediatric UTI in our center had a preponderance of nosocomial multi-drug resistant pathogens.

A community-based study on nasal carriage of Staphylococcus aureus.

Background & objectives: Community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is a major global problem. Colonization rates of MRSA in the community have been reported to range from 0 to 9.2 per cent. The present study was conducted to detect S. aureus nasal colonization and prevalence of MRSA in children (5 to 15 yr) in an Indian community setting of rural, urban and semiurban slums, as also evaluation of an in-house PCR to detect MRSA. Methods: Nasal swabs from children were cultured and S. aureus isolates were processed for antibiotic susceptibility. mecA gene was studied by polymerase chain reaction (PCR) on S. aureus isolates and directly from enrichment broth aliquots inoculated with nasal swabs, at sequential time intervals. Results: The overall prevalence of S. aureus nasal colonization was 52.3 per cent and that of MRSA 3.89 per cent. CA-MRSA nasal carriage was 3.16 per cent in children without prior exposure to health care settings. PCR detection directly on nasal swabs and enrichment broth had a poor sensitivity of 60.42 per cent. Interpretation & conclusions: There was a high rate of S. aureus nasal colonization in the 5-15 yr age group and an alarming rate (3.89%) of community acquired methicillin resistant S. aureus nasal colonization in the community. PCR as a method of direct detection of MRSA from nasal samples needs further fine tuning.