Serra Saji Moses

Abstract

Introduction: Staphylococcus aureus is a major pathogen causing bacteraemia, pneumonia, skin and soft tissue infections (SSTIs), and osteomyelitis. Over the past 50 years, it has acquired resistance to antimicrobials including the penicillinase-resistant ones like methicillin. Rapid identification and susceptibility testing are mandatory to prevent further dissemination of MRSA and to provide effective antimicrobial treatment. Hence, methods used to detect MRSA should be rapid with high sensitivity and specificity. Objectives: 1) To compare various phenotypic methods for MRSA detection. 2) To confirm the phenotypic results with Polymerase Chain Reaction. 3) To evaluate the susceptibility of MRSA isolates to other antimicrobial agents. Methodology: Eighty four MRSA isolates from soft tissue and bone samples identified by the cefoxitin (30mg) disc diffusion method were subjected to Oxacillin Screen Agar (OSA), cefoxitin E-strip, automated identification & sensitivity testing using BD Phoenix system and Polymerase Chain Reaction using the GeneXpert for mecA gene detection. Results: Although all 84 isolates were resistant by cefoxitin disk diffusion, 83 (95.4%) isolates were positive for the mecA gene. The sensitivities of the OSA, cefoxitin E-strip and BD Phoenix system were 79.5%, 80.7%, and 100%, respectively. All the isolates were sensitive to vancomycin and linezolid. 70% of the isolates were sensitive to cotrimoxazole whereas maximum resistance of 76% was seen to ciprofloxacin. Conclusion: Automated identification by BD Phoenix system, if available, can be considered as the most sensitive phenotypic method for MRSA detection, while cefoxitin E-strip is the most appropriate test in a resource poor setting. Keywords: Genotypic methods, Infections, MRSA, Phenotypic methods.

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Abstract

Introduction: Healthcare associated infections (HAI’s) or nosocomial infections are frequently encountered in neonatal intensive care units (NICU’s), resulting in morbidity as well as mortality of new born babies, with varying predisposing factors and microbiological profile. Objective: This study was conducted to identify the most common HAI among the neonates admitted in the NICU, to identify the risk factors of HAI’s in neonates and to compare the bacteriological profile of culture positive cases with the results of environmental survey. Materials and Methods: This was a prospective study, conducted for a duration of one and a half years from December 2018 to May 2020. Environmental samples from the NICU as well as clinical samples from neonates admitted to the NICU of a tertiary care centre for a duration of more than 2 calendar days were collected. Results: The most common HAI in the NICU was VAP (41.6%), followed by CLABSI (21.8%). Statistically significant risk factors for neonatal nosocomial infection were preterm birth, LSCS, presence of comorbidities, Low Birth Weight, absence of breast feeding and Apgar score. The most common Gram negative organism isolated was Acinetobacter baumannii (18.8%) and Gram positive organism as Methicillin Resistant Coagulase negative Staphylococcus (MRCoNS) (13.9%). Results: Acinetobacter baumanni above average isolation rate was matching with the growth of the similar organism each month, according to the surveillance report. Conclusion: The most common HAI among neonates in our study was VAP, majority of which were caused by Gram negative bacteria. Acinetobacter baumanni was found to have an isolation rate above average on environmental surveillance, indicating its role in causing HAI’s in neonates admitted to the NICU. However, this study did not show a definitive association between HAI and the environmental surveillance report.   Keywords: Hospital acquired infections, Neonates, NICU, Environmental surveillance

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