Incidence of Staphylococcus Aureus in Lower Respiratory Tract Infections: An Emerging Trend

Introduction: The pathogen like staphylococcus spp. associated with multidrug resistance is one of the major concerns. Prompt diagnosis of staphylococcal Lower Respiratory Tract Infection (LRTI) with its antibiogram plays a vital role in better outcomes of treatment and reducing the cost of hospital stay of patients.

Aim: To find out incidence of staphylococcal LRTIs.

Materials and Methods: This prosprective cross-sectional study was conducted in the Department of Microbiology, SMBT Institute of Medical Sciences and Research Centre, Nashik, Maharashtra, India. The duration of the study was 23 months, from June 2017 to May 2019. The specimens were screened for staphylococcal species as per the standard bacteriological procedure. The gram-positive, catalase-positive isolates were further subjected to detection of antimicrobial susceptibility patterns as per Clinical and Laboratory Standards Institute (CLSI) guidelines. The data was analysed by using Statistical Package for Social Sciences (SPPS) version 20.0.

Results: The majority of the patients were of old age groups and the average mean age was 57.95±6.18 years. A total of 22/421 Staphylococcus aureus (S. aureus) were isolated from the patients suffering from LRTIs. High incidence was noted in male patients 21/22 (95.5%) than in females 1/22 (4.5%) and 100% of patients were hospitalised with a complaint of LRTIs. The majority of strains were isolated from sputum sample 18/22 (81.8%), followed by 3/22 (13.6%) from pleural aspiration, and 1/22 (4.5%) from endotracheal secretion. Almost 18/22 (81.8%) patients were of pneumonia, followed by 3/22 (13.6%) were of empyema and 1/22 (4.5%) were of sinusitis. All the isolates were sensitive to linezolid, vancomycin, and ceftaroline.

Conclusion: In the present study, LRTI associated with S. aureus was found to be (5.22%). It was also observed that, all strains were sensitive to vancomycin, linezolid, and ceftaroline which is unique. Hence, the staphylococcal infection can be treated with low cost and hospital stay if diagnosed in time by microbiological profile, as the clinical presentation and susceptibility to antimicrobial agents vary in different geographical areas.