BackgroundThe role of bio-aerosols in the spread of disease and spoilage of food has been described in numerous studies; nevertheless this information at South African hospitals is limited. Attributable to their size, bio-aerosols may be suspended in the air for long periods placing patients at risk of infection and possibly settling on surfaces resulting in food contamination. The aim of the study is to assess the microbial composition of the air in the kitchen and selected wards at a typical district hospital in South Africa. Air samples were collected using the settle plates and an SAS Super 90 air sampler by impaction on agar. These microbial samples were quantified and identified using Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) and Analytic Profile Index (API).ResultsMicrobial counts were found to be higher in the fourth (≤6.0 × 101 cfu/m-3) sampling rounds when compared to the first (≥2 cfu/m-3), second (≤3.0 × 101 cfu/m-3) and third (≤1.5 × 101 cfu/m-3) sampling rounds. Genera identified included Bacillus, Kocuria, Staphylococcus, Arthrobacter, Candida, Aureobasidium, Penicillium and Phoma amongst others. The presence of these pathogens is of concern, attributable to their ability to cause diseases in humans especially in those with suppressed host immunity defenses. Furthermore, fungal genera identified (e.g. Candida) in this study are also known to cause food spoilage and fungal infections in patients.ConclusionResults from this study indicate the importance of air quality monitoring in health-care settings to prevent possible hospital-acquired infections and contamination of hospital surfaces including food contact surfaces by airborne contaminants.

The role of hospital surfaces (including surfaces in food preparation areas) in the transmission of hospital-acquired infections (HAI) has been long recognized; however, evidence regarding this critical information is not well documented. This study was conducted at a typical district hospital in the Free State Province of South Africa. Using swabs, surface samples were collected from nine kitchen areas, quantified and identified using the MALDI-TOF MS and API. Fungal counts (1 x 10 3 to 2.3 x 10 5 cfu.cm-2) were higher compared to bacterial counts (1.5 x 10 3 to 1.1 x 10 5 cfu.cm-2). A total of 25 bacterial species and 14 fungal species were identified from hospital kitchen surfaces using the MALDI-TOF MS. Candida was the most common fungal genus identified represented by 11 species while Bacillus was the most common bacterial genus isolated represented by 7 species. The presence of species from the genera Acinetobacter, Enterobacter, Pseudomonas and Candida amongst others on kitchen surfaces could have serious consequences as they have been implicated in various studies as probable causes of hospital acquired infections. The study highlights the need to ensure proper cleaning of working surfaces in the kitchen as well as stringent surveillance and monitoring to ensure the minimal contamination of food products prepared for patients.