Comparison of methods for detection of four common nosocomial pathogens on hospital textiles

Introduction: Although the most common vehicle for transmission of health-care acquired infections is the personto- person transmission route, the role of environment should not be ignored and hospital linen may contribute to the spreading of nosocomial infections. The contact plate method and swabbing are common methods for sampling microorganisms on textiles; however, results are available after two days as they are based on incubation followed by phenotype identification. An important alternative is using quick wash-off methods followed by PCR detection, which shortens the identification process from two days to a few hours.

Methods: The following test microorganisms at different concentrations were inoculated onto textile swatches and dried overnight: Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Clostridium difficile. RODAC plate sampling as well as a non-destructive wash-off method for capturing microorganisms from the textiles using a Morapex device were used. The elution suspension from the Morapex device was used for two methods. In the first method, classical incubation on selective media followed by phenotypic identification was used and in the second method DNA was extracted from the elution suspension followed by amplification and agarose gel electrophoresis to visualize amplified products.

Conclusions: All chosen bacteria were found using all methods. However, the most sensitive proved to be detection using PCR amplification as we detected the sample with initial concentration of 102 cfu/mL inoculated onto the textile surface before drying. The final detectable recovered bacterial concentration on textiles was up to 10 cfu/mL.