DETECTION AND QUANTIFICATION OF BACTERIA ON FREQUENTLY TOUCHED SURFACES AT A WORKPLACE

Abstract

Surfaces frequently touched by personnel at workplaces harbour potential pathogens and may act as a source of infectious diseases and allergic reaction. Contrary to mould growth that usually gives visual discoloration, bacterial growth is often not visible. This study was conducted in April 2021 at a government premise in Selangor, Malaysia using a rapid on-site test based on hydrolase enzyme activity present in bacteria to determine whether frequently touched surfaces at this workplace have been contaminated by bacteria. Ten most frequently touched objects by personnel working in the same building had been identified to be the sampling objects. The Bactiquant-surface (BQS) method was applied in the study using a Mycometer microbial fluorometer detection system with Bactiquant-surface test assays. There were three samples taken from each object surface to ensure higher probability of discovering bacterial contaminations. A 9 cm2 area self-adhesive template was applied to each surface for every sample taken. The samples were then analysed in the laboratory within 24 h of collection. The Bactiquant surface test results were expressed as Bactiquant-surface values (BQSV) and the surface bacterial contaminated levels were differentiated according to the interpretation criteria given. The results showed that none of the objects had been categorised as bacterial contaminated surfaces. Six of them, toilet door handle, water dispenser tap, sink bench, computer keypad, computer mouse and meeting table were categorised as dirty surfaces (BQSV in the range of 26 to 350), while the other four objects were categorised as clean surfaces (BQSV not more than 25). It was found that the dirtiest surface was the toilet door handle, while the cleanest surface was the incubator door handle. In conclusion, there was bacterial presence detected on the frequently touched surfaces at the workplace due to the transmission of organisms by human hands. These objects were often not cleaned or disinfected and could become potential sites for bacterial colonisation.
Keywords: Microbial fluorometer detection system; bacteria hydrolase enzyme activity; bacterial contamination level; frequently touched surfaces; workplace.

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