Surface-attached cells, biofilms and biocide susceptibility: implications for hospital cleaning and disinfection

Abstract

Microbes tend to attach to available surfaces and readily form biofilms, which is problematic in healthcare settings. Biofilms are traditionally associated with wet or damp surfaces such as indwelling medical devices and tubing on medical equipment. However, microbes can survive for extended periods in a desiccated state on dry hospital surfaces, and biofilms have recently been discovered on dry hospital surfaces. Microbes attached to surfaces and in biofilms are less susceptible to biocides, antibiotics and physical stress. Thus, surface attachment and/or biofilm formation may explain how vegetative bacteria can survive on surfaces for weeks to months (or more), interfere with attempts to recover microbes through environmental sampling, and provide a mixed bacterial population for the horizontal transfer of resistance genes. The capacity of existing detergent formulations and disinfectants to disrupt biofilms may have an important and previously unrecognized role in determining their effectiveness in the field, which should be reflected in testing standards. There is a need for further research to elucidate the nature and physiology of microbes on dry hospital surfaces, specifically the prevalence and composition of biofilms. This will inform new approaches to hospital cleaning and disinfection, including novel surfaces that reduce microbial attachment and improve microbial detachment, and methods to augment the activity of biocides against surface-attached microbes such as bacteriophages and antimicrobial peptides. Future strategies to address environmental contamination on hospital surfaces should consider the presence of microbes attached to surfaces, including biofilms.

Histones from Avian Erythrocytes Exhibit Antibiofilm activity against methicillin-sensitive and methicillin-resistant Staphylococcus aureus

“…Biofilm plaques on medical equipment can be traced to 65% of all infections in human medicine20. Environmental cues from within an established biofilm can activate dispersal mechanisms, in which some bacteria revert to the planktonic state and are shed from the biofilm to cause acute infections, including sepsis, or form new biofilms at secondary sites leading to chronic infection.…”

Microbial Biofilms in Pulmonary and Critical Care Diseases

“…Most water distribution systems are colonized with biofilms (69) and this may contribute to the nosocomial transmission of P. aeruginosa, for example (70). Contaminated surfaces in health-care settings are also increasingly recognized as a reservoir for transmission for pathogens such as P. aeruginosa, Acinetobacter baumannii, and S. aureus, particularly within the intensive care unit (ICU) (71,72). Common biocides such as chlorhexidine and triclosan are ineffective at killing biofilm bacteria, including P. aeruginosa and S. aureus (73), and biofilms have been recovered from sanitized hospital surfaces (72).…”

Dos and don’ts for hospital cleaning

“…Organisms inevitably evolve characteristics to help them survive desiccation stress, although there is a trade-off between the capacity for multidrug resistance and survival in biofilm [48]. The relevance of biofilm for hospital cleaning remains to be fully ascertained [49].…”