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Molecular surveillance of Staphylococcus aureus on frequently touched sites in public hospitals in KwaZulu-Natal, South Africa.

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There is an escalation in the prevalence of hospital-acquired infections (HAI) due to the transfer of pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), within the hospital environment. Pathogens contaminate inanimate objects and are transmitted in the hospital environment through direct hand contact, of which healthcare workers and patients act as vectors. This study aimed to conduct surveillance of methicillin-resistant S. aureus (MRSA) on frequently touched hospital environment sites of selected public hospitals from different healthcare levels in KwaZulu-Natal, South Africa. Eleven predetermined frequently touched sites in the general, paediatric and ICU wards were swabbed viz. occupied and unoccupied beds, ward telephones, drip stands, nurses’ tables, door handles of laundry rooms, mops, sinks, ventilators, blood pressure machines and patient files. The swabs were plated on selective chromogenic media for Staphylococcus aureus (S. aureus) isolation and phenotypic identification. Total genomic DNA was extracted using the conventional boiling method. The presence of the S. aureus thermo-nuclease nuc gene was confirmed using the polymerase chain reaction (PCR). Antibiotic susceptibility tests were conducted by performing the Kirby-Bauer disk diffusion assays, according to CLSI guidelines, to determine the isolates' resistance profiles to nine antibiotics. The mecA gene, an MRSA indicator, and genes encoding resistance and virulence were identified through PCR. Genomic DNA was extracted using the Quick-DNATM Miniprep Plus kit, and ERIC-PCR was conducted to determine the clonality of the isolates. Pearson’s correlation, Fisher’s exact test and Chi-Square test were implemented using the SPSS software version 25 (IBM SPSS Statistics) for statistical analyses. The statistical significance determined by a probability value that was less than 0.05 (p < 0.05). An overall prevalence of 12.7 % (99/777) for S. aureus isolates was obtained. Of these, 89.9 % (89/99) were MRSA, and only 10.1 % (10/99) of the total collected isolates were identified as methicillin-susceptible S. aureus (MSSA). The sites with the highest prevalence were the occupied beds (16.2 % (16/99)), unoccupied beds (16.2 % (16/99)), patient files (14.1 % (14/99)), ward telephones (13.1 % (13/99)) and nurses’ tables (14.1 % (14/99)). The sites with the lowest prevalence were the blood pressure machines (6.1 % (6/99)), drip stands (6.1 % (6/99)), ventilator (6.1 % (6/99)), door handle (4 % (4/99)), mop (3.0 % (3/99)) and sink (1.0 % (1/99)). The Pearson’s Chi-square and Fischer’s exact test indicated a significant relationship (p < 0.05) between the mecA gene and the collection site. A significant relationship (p < 0.05) was identified between the hospital and the tetK, ermC, aac (6')-aph (2") and LukS/F-PV genes. ERIC-PCR produced bands for 87.8 % (87/99) of the isolates; 12.1 % (12/99) were non-typeable. Our findings have highlighted the S. aureus contamination on frequently touched hospital sites, virulence and resistance, and the clonal diversity of S. aureus isolates in the hospital environment of four KwaZulu Natal public hospitals in the eThekwini district. Our findings may be used as a baseline for future surveillance initiatives to improve hospital hygiene through IPC strategies centred around S. aureus in KwaZulu-Natal public hospitals.


Masters Degree. University of KwaZulu-Natal, Durban.