infection prevention
infection prevention
By David W . Koenig , PhD Biofilms and Healthcare
Healthcare facilities — such as hospitals , nursing homes and outpatient facilities — are opportunistic locations for acquiring secondary infections unrelated to a patient ’ s primary condition . Healthcare-acquired infections ( HAIs ) are a primary concern for healthcare providers , administrators , and governments worldwide due to the reduced quality of healthcare and the considerable associated socioeconomic costs resulting from extended hospital stays for infection treatment .
Some of the most common HAI types occur during the use of indwelling medical devices , such as a catheter , endotracheal tube , feeding tube or prosthesis . According to the Centers for Disease Control and Prevention ( CDC ), the most common underlying cause of infections related to indwelling medical devices is the ability of microorganisms to adhere to the surface of devices and form biofilms . Biofilms are often associated with tissue infections such as chronic wounds , skin infections , endocarditis , chronic otitis media and cystic fibrosis .
Biofilms are a gathering of microbes that colonize various surfaces . Many biofilms are beneficial . The beneficial human microbiome consists of diverse biofilms on the skin , teeth and mucosa of the gut , nasal , and reproductive organs ; however , if a biofilm contains pathogens , these biofilms can become a severe concern for healthcare facilities , leading to HAIs .
The aspect of most concern is increased resistance to antimicrobials and antibiotic therapy ; because of this concern ’ s broad acceptance that the most effective way to reduce the incidence of medical device-related infections is to prevent primary microbial adhesion and subsequent biofilm formation .
Biofilms produce an extracellular polymeric substance ( EPS ) that protects the microbes in the biofilm . EPS interferes with the penetration of antibiotics or antimicrobials through biofilm . EPS interference is compounded by the cells in the biofilm having an altered physiology that further protects those cells from any antimicrobial that might penetrate the biofilm . Biofilms also provide the microbes with an environment that allows cell-cell communication and quorum sensing and enhances the transfer of genetic elements and resistance genes . Indeed , biofilm bacteria can transform into a persistent state that mimics a spore . Ultimately , biofilms increase the prevalence of antibiotic-resistant microbes and the risk of transmission to the caretaker and patient .
Healthcare environmental biofilms can act as reservoirs for the transmission of pathogens . Biofilms are commonly associated with surfaces that remain wet ; however , a biofilm cover surface does not necessarily have to appear watery to the eye for a biofilm to persist . Recently , dry surface biofilms have been receiving extensive study . Dry surface biofilms form an exterior veneer while the surface is wet and then dry when the moisture dissipates . Biofilm EPS plays a critical role in the persistence of a dry biofilm , allowing the retention of enough water for sustained survival .
Biofilm “ hot spots ” can include drains , sinks , plumbing connections , areas of toilets that remain wet and not cleaned with mechanical action , bathrooms , sink traps , air filtration mediums , window ledges and seals , air conditioning systems , fabrics , and carpets and
rugs . Dry surface biofilms develop on various surfaces , such as blood pressure cuffs , intravenous poles , door handles , touch screens , and cell phones . Dispersion of cells from biofilms can perpetuate microbial resistance , recurrence , and transmission of dangerous pathogens in the healthcare environment .
The types of microbes associated with biofilms are very diverse . The most common bacteria associated with hospital device-related infections is Staphylococcus epidermidis . Other hospital biofilm bacteria are methicillin-resistant Staphylococcus aureus ( MRSA ), viridans streptococci , Enterococcus faecalis , vancomycin-resistant Enterococci ( VRE ), Escherichia coli , Pseudomonas aeruginosa , Acinetobacter baumannii , Proteus mirabilis , and Klebsiella pneumoniae . Recently , the fungi Candida auris has emerged as a critical biofilm-associated pathogen . Other medically associated fungi that form biofilms are Aspergillus , Cryptococcus , Trichosporon , Coccidioides , and Pneumocystis — furthermore , human viruses and bacteriophages are present in biofilms .
Control of biofilms is complex . For device-related biofilms , various prevention strategies are initiated . One process is to impregnate the device with leachable antimicrobials such as silver . Another is to coat the surface with anti-adherents that interfere with the initial attachment of the microbe to the surface , interfering with the first step of biofilm formation . There is also the possibility of imprinting micro-patterns on surfaces that inhibit biofilm formation . These tactics have allowed various levels of protection from biofilm formation on devices . Removing biofilms from animate surfaces commonly involves mechanical methods such as water jets and sonic disruption , widely found in dental cleaning .
Prevention and removal of biofilms on inanimate environmental surfaces are just as challenging . The biofilm is often on a surface that is hard to reach or in a dead leg within a water system . Cleaned and disinfected surfaces contiguous to the contaminated area can be readily re-contaminated by biofilm dispersion leading to a transmission hot spot . A strategy to help reduce surface recontamination is to employ a persistent antimicrobial . For example , copper-containing materials , such as bed rails , have prevented biofilm formation . Using a residual disinfectant may also be an excellent option to reduce the recontamination of a surface .
Biofilms are inherently resistant to chemical disinfectants ; therefore , mechanical and chemical methods are usually employed to effectively treat environmental biofilms . Mechanical methods may include abrasive scrubbing , high-power sprays and jets , and sonic cleaning , to name a few . Strong oxidants such as peracetic acid are good candidates for treating biofilms , although insufficient evidence exists to distinguish between product performance and biofilms . Recently , there has been a trend for disinfectant manufacturers to evaluate disinfectant performance against biofilms . Additionally , if the biofilm matrix or dead cells remain on a surface after cleaning , biofilms will form faster than surfaces free of the contaminating material . Removal of the biofilm matrix after disruption on surfaces points out the importance of removing biofilm debris as a prophylactic for future biofilm control .
Healthcare biofilm control is a cornerstone in reducing antimicrobial resistance and making a significant dent in HAIs . Everyone involved in cleaning must better understand and grasp the types of disinfectants required to control healthcare biofilms . Therefore , more effort is needed in all these knowledge areas to help healthcare practitioners and caregivers develop efficient approaches to identify , prevent , and remove biofilms .
10 june 2023 • www . healthcarehygienemagazine . com