engleski

The survival of different bacteria in dry conditions

The most common nosocomial pathogens may well survive and persist on different surfaces in hospital environment and can thereby be a continuous source of infection, especially in immunocompromised host. The purpose of this study was to determine the survival of different desiccated bacteria on the plastic surfaces. In our experiments, we compared the abilities of different clinical isolate of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Salmonella enterica ser. Typhimurium and Staphylococcus aureus to survive under dry conditions. Inoculums were prepared in sterile water and 6 x 20 μl of bacterial suspension (~ 10(8) cfu/ml) were deposited in 96 wells plates and dried for one hour under laminar flow hood. After that, the plates with dried bacteria, as well as plates with control bacterial suspensions (wet conditions) were stored at room temperature. At different time points bacteria were rehydrated and cultivated in LB and blood agar. After incubation on 37°C for 24 hours, the number of bacteria per well was determined. Our results showed that K. pneumoniae had the shortest survival time of only 6 days, while A. baumannii tended to survive more than 50 days. E. coli and S. Typhimurium were cultivable for 10 days, P. aeruginosa for 14 days and S. aureus for 28 days.In conclusion, A. baumannii and S. aureus had the highest tolerance to desiccation and the longest survival on plastic surface. Further studies are needed to determine the infectivity and viability of bacteria exposed to desiccation.

bacteria; desiccation; survival; plastic surfaces

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