Detection and Characterisation of Heteroresistant Vancomycin Intermediate Staphylococcus aureus (hVISA) using Phenotypic and Genotypic Methods
Journal Title: Journal of Clinical and Diagnostic Research - Year 2019, Vol 13, Issue 5
Abstract
ABSTRACT Introduction: Vancomycin remains the drug of choice to treat infections caused by Methicillin Resistant Staphylococcus aureus (MRSA). Frequent therapeutic failures arise due to the emergence of strains with reduced susceptibility to vancomycin and difficulty in detecting these isolates. Therefore, improvements in screening and confirmatory tests to detect these isolates are required. Aim: To detect heteroresistant Vancomycin Intermediate Staphylococcus aureus (hVISA) isolates among Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA) obtained from various clinical samples and to study the phenotypic and genotypic charecteristics of these strains. Materials and Methods: This study was carried out in the Department of Microbiology, Chettinad Hospital and Research Institute, Kelambakkam, Chennai, Tamil Nadu, India. A total of 468 non-duplicate S.aureus strains obtained from various clinical samples during a period of two years from September 2014 to November 2016 were included in the study. MRSA isolates and hVISA/VISA isolates were detected by screening and confirmatory methods (MRSA screen by cefoxitin disc, hVISA/VISA screen by brain heart infusion agar with 6 μg vancomycin and hVISA/VISA confirmation by PAP-AUC method). Agr polymorphism in hVISA/VISA was analysed by duplex PCR. Accessory gene regulator (Agr) dysfunction in these strains was studied by their colony spreading property in soft agar and autolytic property by Triton X-100 induced lysis. The results were analysed using IBM SPSS (version 21.0) software. Results: Out of 468 S.aureus strains, 114 (24%) strains were detected as MRSA and 33 (7.0%) were hVISA/VISA strains. Among MRSA detected, 11 (9.5%) strains were confirmed as hVISA/VISA. All hVISA/VISA isolates showed reduction in autolytic activity. Colony spreading property was appreciated in 13 (39%) of these isolates. Out of the 33 hVISA/VISA strains, majority belonged to agr I, III and II and the least number of isolates belonged to agr IV. Conclusion: It was concluded that hVISA/VISA strains have diverse virulence properties and are detected in both MRSA and MSSA strains. Therefore, surveillance of these strains among S.aureus isolates having vancomycin MIC’s ≤1.5 μg/mL in laboratory settings is needed.
Authors and Affiliations
Alice Peace Selvabai, Shameem Banu Abdul Sattar, Perumal Jayaraman, Priyadarshini Shanmugam
Keywords
Related Articles
- EP ID EP586061
- DOI 10.7860/JCDR/2019/41127.12868
- Views 150
- Downloads 0
Scrub Typhus Complicated by Acute Respiratory Distress Syndrome and Haemophagocytic Lymphohistiocytosis in a Young Patient
ABSTRACT Scrub typhus is an endemic rickettsial disease causing vasculitis involving the small vessels of the body. Haemophagocytic Lymphohistiocytosis (HLH) is a hyperinflammatory syndrome characterised by excessive unb...
A Community Based Study on Pelvic Inflammatory Disease in Postmenopausal Females: Microbiological Spectrum and SocioDemographic Correlates
Introduction: Pelvic Inflammatory Disease (PID) is a common and serious complication of sexually transmitted diseases in young women but is rarely diagnosed in the postmenopausal women. Very few studies have been done re...
Role of Low Density Lipoprotein Cholesterol in Progression of Diabetic Retinopathy
ABSTRACT Introduction: Various cross-sectional studies indicate that dyslipidemia and increased activity of enzyme Aldose Reductase (ALDR-2) are associated with the establishment of Diabetic Retinopathy (DR). However, it...
A Study to Assess the Functional Outcome of Decompression and Posterior Lumbar Interbody Fusion of Low Grade Spondylolisthesis of Lumbar Vertebra
Introduction: Spondylolisthesis is defined as the forward displacement of one vertebra over the vertebra below. It is often accompanied by spinal canal stenosis and compression, which is the cause of all the symptoms. Ai...
Protein Mediated Oxidative Stress in Patients with Diabetes and its Associated Neuropathy: Correlation with Protein Carbonylation and Disease Activity Markers
Introduction: Free radicals have been implicated as Diabetes Mellitus (DM) contributors in type 2 DM and its associated Diabetes Mellitus Neuropathy (DMN). However, the potential for protein mediated oxidative stress to...