Survival capability of healthcare-associated, multidrug-resistant bacteria on untreated and on antimicrobial textiles

Healthcare-associated infections are of global concern, and textiles can contribute to the transmission of pathogens. In this study, we examined quantitatively the survival capability of 60 multidrug-resistant bacterial strains from four species ( Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus and Enterococcus faecium) on untreated cotton textile in clinically relevant incubation periods. We determined the antibacterial efficiency of textiles treated either with quaternary ammonium compound (QAC)-containing Sanitized T99-19 liquid (50 m/m% Dimethyltetradecyl (3-(trimethoxysilyl)propyl) ammonium-chloride) or with silver salt-containing Sanitized T27-22 Silver liquid (2 m/m% AgCl and 8 m/m% TiO ₂ ) as well. Finally, we compared the results of the healthcare-associated, multidrug-resistant strains and antibiotic-sensitive, quality control standard strains (ATCC 25922, ATCC 11105 Escherichia coli, and ATCC 25923, ATCC 6538 Staphylococcus aureus) often used in antimicrobial efficiency tests. The results revealed that all investigated multidrug-resistant bacteria are able to survive on untreated cotton textile and pose health risk in hospitals. During one day the T27-22-Silver-treated textile was able to eliminate most of the Gram-positive pathogens, reducing the risk of cross-contamination, but none of the examined agents destroyed the multidrug-resistant, Gram-negative isolates. The antibiotic-susceptible and the multidrug-resistant Staphylococcus aureus strains had similar survival capability and biocide-tolerance, while the risk of infections caused by multidrug-resistant, Gram-negative pathogens could be extremely underestimated using only ATCC Escherichia coli standard strains. Our results also draw attention to the careful evaluation of antimicrobial efficiency tests and indicate that a significant reduction of bacterial count does not necessarily mean significant antibacterial efficiency that would be suitable to avoid infections.