Prevalence of Nasal Carriage of Methicillin Resistant Staphylococcus aureus among Patients, Health Care Workers and Patients’ Care Takers at Kabale Regional Referral Hospital, South Western Uganda
Authors: Busingye Jude Collins , Bazira Joel , Musinguzi Benson , Ssemakadde Thomas , Nalumaga Pauline , Were Jackson , Mukundane Bruno , Mwebembezi Frank , Twinomugisha Phionah , Byarugaba Frederick 
Published: April 2023

Abstract
Background
Methicillin Resistant Staphylococcus aureus (MRSA) is a type of Gram-positive bacterium that is genetically different from other strains of Staphylococcus aureus by virtue its capability to overcome the actions of methicillin and many other antibiotics making it difficult to treat.
MRSA development is as the result of the triggering of the resistance gene, mecA, which react by inhibition of the β-lactams from rendering inactive transpeptidases indispensable in cell wall synthesis. MRSA is one of the known major hospital acquired bacteria that causes severe ill health and mortality world over.
The global prevalence of MRSA isolated in swabs samples differs from health care facility to another in various countries, with high rates ranging from 32–52% as reported in low resource settings in the developing countries.
In Kabale Regional Referral hospital(KRRH), the prevalence of MRSA stands at 54% among isolates from wound swabs on surgical ward according to studies conducted by Andrew et al., 2016. However, there is hardly any known information of the prevalence of MRSA in nasal swabs of Health care workers (HCWS), patients and patients’ caretakers in KRRH Uganda. This study aimed at ascertaining to the prevalence of nasal carriage of MRSA among HCWs, patients and patients’ caretakers at KRRH.
Methods
A grand total of 382 samples were collected from the several HCWs, patients and patients’ caretakers in different wards of KRRH in Kabale District. The nasal swab specimens were inoculated and cultivated on Mannitol salt agar at 37°C for 24 hours and the colonies subjected to Gram staining, Catalase, Coagulase test reactions and confirmed as S. aureus bacteria on DNase testing agar.
Identification for MRSA was performed using the Cefoxitin (30μg) disc on Mueller Hinton agar medium by disc diffusion technique, antibiotic sensitivity testing was conducted using the Kirby–Bauer disc diffusion method on Mueller–Hinton agar (MHA) and results were interpreted in accordance with Clinical and laboratory standards institute (CLSI) 2020 guidelines.
S. aureus mecA and pvl genes were identified and subsequently detected by PCR amplification assay using gene-specific primer pairs to confirm MRSA.
Results
Out of 382 study participants, 130 participants had MRSA identified phenotypically out of which, 115 of the participants, had MRSA as confirmed by the mec A gene.
Generally, the prevalence of nasal carriage of MRSA in Kabale Regional Referral Hospital was found out to be 30.1%. It was found to be 31.49% in patients, 29.7% in HCWs, and 28% among patients’ caretakers.
MRSA was highly sensitive/Susceptible to Ceftaroline, Clindamycin, Ciprofloxacin, Linezolid, Chloramphenicol and Tetracycline.
Conclusion
Generally, the prevalence of nasal carriage of MRSA in the study area was found to be 30.1% and 31.49% in patients, 29.7% in HCWs, and 28% among patients’ caretakers.
The highest nasal carriage rate of MRSA was found in patients (31.49%). MRSA was more common in OPD department, followed by medical ward, Gynecology and Obstetrics wards.
MRSA strains were sensitive to Ceftaroline, Clindamycin, Ciprofloxacin, Chloramphenicol, Linezolid and Tetracycline. Most of MRSA isolates were multidrug resistant to antibiotics such as Cefoxitin, Sulfamethoxazole-Trimethoprim, and Penicillin.