Isolation of pathogenic bacteria and opportunistic pathogens from public telephones

A survey of 20 randomly selected public telephones in the central business district of Melbourne, Australia, revealed the presence of contaminating pathogenic bacteria and opportunistic pathogens. Bacteria were recovered from all telephones sampled: 40% were contaminated with coagulase-positive Staphylococcus aureus and 80% with lactose-fermenting and non-fermenting bacteria, indicating possible faecal contamination. Further identification revealed the presence of the following enteric and non-enteric bacteria: Acinetobacter anitratus, Enterobacter cloacae, Escherichia coli and Pantoea agglomerans (formerly Enterobacter agglomerans). A viridans Streptococcus, most probably from the 'S. mitis' group, was recovered from one of the telephones. All these bacteria are pathogens or opportunistic pathogens. Inoculation of one of the S. aureus isolates onto an inert plastic surface and incubation at room temperature indicated that, although a significant reduction in the recovery of viable bacteria was observed after one day, over 10% of bacteria survived for up to seven days. This was reduced to less than 5% survival after 14 days. Our results suggest that telephone surfaces may serve as potential reservoirs for the transmission of disease-causing bacteria.