Meticillin-resistant Staphylococcus aureus (MRSA) contamination of ambulance cars after short term transport of MRSA-colonised patients is restricted to the stretcher

SARS-CoV-2 Contamination of Ambulance Surfaces and Effectiveness of Routine Decontamination Procedure: A Classic Hygiene Lesson for A Novel Pathogen

The efficacy of standard operating procedures (SOPs) for the decontamination of ambulances against SARS-CoV-2 has been debated. In Italy, the differential use of ambulances was implemented by regional health authorities, with selected vehicles being used exclusively for transporting COVID-19 patients. We investigated the presence of SARS-CoV-2 on high-touch surfaces in ambulances to assess contamination dynamics and the effectiveness of decontamination SOPs. Four high-touch surfaces were sampled before and after decontamination (T0; T1). The gloves of the EMS crew chief were also sampled. RNA extraction was performed with a commercial kit, followed by RT-qPCR molecular detection of SARS-CoV-2. A total of 11 transports were considered. Seven transports had at least one positive sample; all were related to a COVID-19 patient. Three of the negative transports had dealt with COVID-19 case, and one had dealt with a COVID-19-negative patient. One door handle and one oxygen knob were positive at T0, with negative T1 swabs. The monitors were positive in 5 transports at T0, yet they were never positive at T1. Three stretcher handles tested positive at T0, and two of them also at T1, possibly having bypassed decontamination during personnel dismounting. Gloves were contaminated in five transports, in which 1 to 3 additional samples (monitor, knob, stretcher) resulted as positive. Overall, the efficacy of decontamination SOPs was confirmed under the unprecedented conditions of the COVID-19 emergency. However, the importance of correct hand-hygiene and glove-disposal should be further emphasized through the dedicated training of EMS personnel.

Microbial contamination on ambulance surfaces: A systematic literature review

BACKGROUND

Healthcare-associated infections (HAIs) are infections that patients acquire while receiving medical treatment in a healthcare facility. During ambulatory transport, the patient may be exposed to pathogens transmitted from emergency medical service (EMS) personnel or EMS surfaces.

AIM

To determine whether organisms commonly associated with HAIs have been detected on surfaces in the patient care compartment of ambulances.

METHODS

Five electronic databases - PubMed, Scopus, Web of Science, Embase, and Google Scholar were used to search for articles using inclusion and exclusion criteria following the PRISMA checklist. Inclusion criteria consisted of articles published in English, between 2009 - 2020, had positive samples collected from the patient care compartment of a ground ambulance, and reported sample collection methods of either swab sampling and/or Replicate Organism Detection and Counting (RODAC) contact plates. Studies not meeting these criteria were excluded from this review.

FINDINGS

From a total of 1,376 articles identified, 16 were included in the review. Organisms associated with HAIs were commonly detected in the patient care compartment of ambulances across a variety of different surfaces, including blood pressure cuffs, oxygen apparatuses, and areas of patient stretchers.

CONCLUSION

A high prevalence of pathogenic bacteria in ambulances suggest that standard protocols related to cleaning compliance may not be effective. The primary recommendation is that designated subject matter experts in infection prevention should be incorporated as liaisons in the pre-hospital setting, acting as a link between the pre-hospital (e.g., ambulance transport) and hospital environments.

Bacteriological Surveillance of Ambulance Vehicles from a Tertiary Care Hospital of North India

Objective An ambulance is a medically equipped vehicle which is used in case of any medical emergency for the transport of patients to treatment facilities. The ambulances help in the transportation of thousands of patients per year, and such patients may carry infectious microorganisms which pose a major threat to the treatment of such patients. In this study, we analyzed the extent of bacterial contamination in our ambulance vehicles and measured the degree of antimicrobial resistance among isolated pathogens.

Material and Method This study included five ambulances of our tertiary care hospital and different random sites were swabbed in each vehicle. These were selected based on their well-known high frequency of contact by emergency personnel and patients. Swabs were inserted into sterile test tubes containing normal saline and immediately transferred to our microbiology laboratory to identify bacterial contaminants utilizing standard microbiological procedures.

Result A total of 198 swab samples were collected from all the five ambulances, out of which 170 (85.8%) swabs were sterile and 28 (14.2%) swabs yielded potentially pathogenic bacterial isolates. The highest contamination rate with pathogenic bacteria was detected in the oxygen flow meter knob (60%), suction machine tubing (60%), and stethoscope (40%). Staphylococcus aureus (32%) was the most frequently detected microorganism.

Conclusion Our study showed low prevalence of bacterial contamination in ambulances because of good infection control policy of our hospital, however, some areas still need improvement and require proper standard operating procedures of disinfection policies of these emergency vehicles.

The Impact of a Novel Operational Readiness Response Model on the Environmental Cleanliness of Emergency Ambulances

Objectives: Environmental cleanliness of emergency ambulances may be associated with increased risk of healthcare acquired infection (HAI). Surface cleanliness, measured using adenosine triphosphate (ATP) testing, has been demonstrated to correlate with potentially harmful levels of microbial pathogens. In most ambulance services, environmental cleanliness of ambulances and the equipment within them is the responsibility of paramedics. In 2016 NSW Ambulance introduced the Make Ready Model (MRM), in which ambulances are systematically cleaned by non-clinical support staff at the end of each shift. This prospective study aimed to 1) provide a baseline level of ambulance cleanliness; and 2) compare the MRM to a standard cleaning model (SCM). Methods: A prospective comparative study was conducted comparing cleanliness of ambulances in the SCM to those in the MRM. Adenosine-triphosphate (ATP) bioluminescence testing was performed in a pseudo-randomised sample of ambulances. Six 'high touch' areas within each ambulance were systematically sampled. Testing occurred without warning to operational staff. The primary outcome was 'overall bioburden' (OB)' measured in radiant light units ('RLU'). Non-parametric tests were used to assess differences in RLU values between each of the test points, while Poisson multivariate regression was used to compare median overall bioburden between the two groups, adjusting for the confounder variable of 14-day ambulance workload. Results: Sixty-eight ambulances were sampled, 32 from the SCM and 36 from the MRM. Median surface bioburden was significantly lower in the MRM for four of the six test points (preparation table, mobile data terminal, stretcher handles and steering wheel). For the primary outcome of overall bioburden, the unadjusted MRM OB was 35% lower than for the SCM group (RR 0.65 (0.64-0.66; p < 0.01)). After adjusting for the significant confounding variable of 14-day workload, the OB was 38% lower for the MRM group (ARR 0.68 (0.61-0.63; p < 0.001)). Conclusion: The innovative MRM cleaning system was associated with significantly improved cleanliness in frontline emergency ambulances. The magnitude of improvement in cleanliness suggests this cleaning model has the potential to make a major contribution to infection control strategies in paramedicine. Future research should focus on cost effectiveness of the MRM and its applicability to regional and remote ambulance service operations.

Methicillin Resistant Staphylococcus aureus and public fomites: a review

Staphylococcus genus is a Gram-positive coccus normally associated with skin and mucous membranes of warm-blooded animals. It is part of the commensal human microflora, or found in animals, or contaminating surfaces in the community and hospital settings. Staphylococcus aureus is the most pathogenic species belonging to this genus, as it possesses a collection of virulence factors that are expressed solely to evade the immune system. The increase in the misuse of antimicrobial agents predisposed S. aureus to develop antibiotic resistance, including the resistance to methicillin which led to the emergence of Methicillin-Resistant S. aureus (MRSA). MRSA is considered one of the most dangerous nosocomial pathogens causing many hard to treat infections in hospitals and was named as Hospital Associated MRSA (HA-MRSA). Over the past 20-25 years, MRSA was isolated from community settings and thus Community Associated MRSA (CA-MRSA) has emerged. Inside hospitals, MRSA has been isolated from fomites in contact with patients, as well as staff's protective and personal items. This review highlights the worldwide prevalence of MRSA on fomites within the contexts of hospital and community settings.

A two-armed, randomised, controlled exploratory study of adding the AmbuGard cleaning system to normal deep-cleaning procedures in a regional ambulance service

Background:

Ambulance services transport patients with infections and diseases, and could pose a cross-transmission risk to patients and staff through environmental contamination. The literature suggests that environmental pathogens are present in ambulances, cleaning is inconsistent and patient/staff impact is difficult to quantify. Eco-Mist developed a dry misting decontamination system for ambulance use called AmbuGard, which works in < 30 minutes and is 99.9999% effective against common pathogens. The research question is: ‘What pathogens are present in North East Ambulance Service ambulances and what impact does adding AmbuGard to the deep-cleaning process make?’.

Methods:

A two-armed, randomised controlled trial enrolled 14 ambulances during their regular 24-week deep clean, which were 1:1 randomised to deep cleaning (control arm) or deep cleaning plus AmbuGard (intervention arm). Polywipe swabs were taken before and after cleaning from five locations selected for high rates of contact (steering wheel, shelf, side-door grab rail, patient seat armrest, rear door handle/grab rail). Microbiology culture methods identified the presence and amount of bacterial organisms present, including the selected pathogens: Enterococcus spp.; Enterobacter spp.; Klebsiella spp.; Staphylococcus aureus; Acinetobacter spp.; Pseudomonas spp.; Clostridium difficile; coagulase-negative staphylococci (CoNS). The researcher taking the swabs and the laboratory were blinded to the trial arm.

Results:

Pathogens of interest were found in 10 (71%) vehicles. CoNS were found in all vehicles. Pathogens were found on all locations swabbed. Normal deep cleaning was effective at eliminating pathogens and the addition of AmbuGard showed no obvious improvement in effectiveness.

Conclusion:

Pathogens associated with healthcare-acquired infections were found throughout all ambulances. Normal deep cleaning was effective, and adding AmbuGard showed no obvious improvement. This was a small study at a single point in time. Further research is needed into temporal trends, how to reduce pathogens during normal clinical duties and patient/staff impact.

Rapid metagenomics analysis of EMS vehicles for monitoring pathogen load using nanopore DNA sequencing

Pathogen monitoring, detection and removal are essential to public health and outbreak management. Systems are in place for monitoring the microbial load of hospitals and public health facilities with strategies to mitigate pathogen spread. However, no such strategies are in place for ambulances, which are tasked with transporting at-risk individuals in immunocompromised states. As standard culturing techniques require a laboratory setting, and are time consuming and labour intensive, our approach was designed to be portable, inexpensive and easy to use based on the MinION third-generation sequencing platform from Oxford Nanopore Technologies. We developed a transferable sampling-to-analysis pipeline to characterize the microbial community in emergency medical service vehicles. Our approach identified over sixty-eight organisms in ambulances to the genera level, with a proportion of these being connected with health-care associated infections, such as Clostridium spp. and Staphylococcus spp. We also monitored the microbiome of different locations across three ambulances over time, and examined the dynamic community of microorganisms found in emergency medical service vehicles. Observed differences identified hot spots, which may require heightened monitoring and extensive cleaning. Through metagenomics analysis it is also possible to identify how microorganisms spread between patients and colonize an ambulance over time. The sequencing results aid in the development of practices to mitigate disease spread, while also providing a useful tool for outbreak prediction through ongoing analysis of the ambulance microbiome to identify new and emerging pathogens. Overall, this pipeline allows for the tracking and monitoring of pathogenic microorganisms of epidemiological interest, including those related to health-care associated infections.

The impact of an ambulance vehicle preparation service on the presence of bacteria: a service evaluation

Introduction:

Around 300,000 patients a year in England acquire a healthcare-associated infection (HAI) while being cared for by the NHS. The contribution from NHS Ambulance Services is not known, but previous studies have identified the presence of pathogenic bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus, including resistant strains in some cases, inside ambulances. To improve ambulance cleanliness, Yorkshire Ambulance Service NHS Trust (YAS) piloted an Ambulance Vehicle Preparation Service (AVPS) at two ambulance stations, where staff were tasked with ensuring every ambulance at these stations was cleaned every 24 hours.

Methods:

Adenosine triphosphate (ATP) bioluminescence testing was conducted on 16 ambulances at the two pilot AVPS stations and on 18 ambulances at four ‘business as usual’ (BAU) ambulance stations using a Hygiena SystemSURE luminometer. Swabs were obtained from 10 pre-selected locations inside each ambulance.

Results:

Between November 2016 and August 2018, a total of 690 swabs were obtained and recorded from 34 ambulances. Overall, median relative light unit (RLU) values for both groups were < 100, with only the BAU group having an upper quartile value > 100. However, when stratified by swabbing area, three areas had a median RLU of > 100 in the BAU group: suction unit handle, steering wheel and airway seat shelf. In addition, the upper quartile RLU values for the grab rail above the stretcher and the passenger seat in the BAU group were also > 100. No swab areas had a median RLU > 100 in the AVPS group.

Conclusion:

A dedicated AVPS results in better cleaning of ambulance vehicles than the existing cleaning system utilising operational crews. The areas most likely to be contaminated are the suction unit handle, steering wheel, airway seat shelf and grab rails. The position of equipment and the materials that equipment are constructed from should have infection prevention and control (IPC) as a consideration.

Ambulance vehicles as a source of multidrug-resistant infections: a multicenter study in Assiut City, Egypt

Background

Ambulances may represent a potential source of infection to patients, patients’ relatives, and paramedical staffs. In this study, we analyzed the extent of bacterial contamination in ambulance vehicles and measured the degree of antimicrobial resistance among isolated pathogens.

Materials and methods

Twenty-five vehicles were included and 16 sampling points were swabbed in each vehicle. Then the swabs were immediately transferred to the laboratory to identify bacterial contaminants utilizing standard microbiological procedures and API^® systems. Antibiotic susceptibility testing and screening for methicillin-resistant staphylococci and extended spectrum β-lactamases (ESBLs)-producing Gram-negative rods were carried out.

Results

A total of 400 samples were collected, 589 bacteria were isolated and 286 (48.6%) of the isolates were potentially pathogenic. The highest contamination rate with pathogenic bacteria was detected in suction devices (75.8%) and stethoscopes (67.7%). Staphylococci were the most frequently detected microorganisms (n=184) followed by Klebsiella spp. (49), Escherichia coli (40), Citrobacter spp. (7), and Proteus spp. (6). Staphylococci were mostly sensitive to vancomycin, whereas Gram-negative bacteria were sensitive to imipenem. Overall, 46.1% of Staphylococcus aureus were methicillin resistant, whereas 20.4% of the coagulase-negative staphylococci were methicillin resistant. Moreover, 36.7% of Klebsiella spp. and 27.5% of E. coli were ESBL producers.

Conclusion

Our study provides evidence that ambulances represent a source of prehospital multidrug-resistant infections.

MRSA prevalence among patient transport staff in Hamburg

Introduction: Patient transport employees frequently come into contact with multidrug-resistant organisms (MDROs) and therefore are at a greater risk of infection than the general population. These pathogens pose a significant challenge for employees of patient transport services since they can spread over long distances through patient transfers. To date, little is known about the occupational risk of MRSA infection in patient transport settings. Methods: A cross-sectional study was conducted to investigate the prevalence of MRSA in patient transport personnel, including taxi drivers, as well as the potential risk factors for MRSA colonization. For screening, nasal swabs were taken. When an individual was tested positive, a control swab was taken; if this confirmed a positive result, decolonization measures were offered. A molecular biological examination of the MRSA samples was performed. Results: A total of 222 patient transport employees were screened and 7 employees tested positive, putting the MRSA prevalence at 3.2% (95% CI 1.4-6.5). Significant risk factors among patient transport staff (PTS) for testing positive were the use of antibiotics (OR 11.9; 95% CI 1.8-78.4) and hospital admission (OR 6.9; 95% CI 1.1-45.9). MRSA swabs were also performed on a total of 102 taxi drivers who provide patient transport services. The MRSA prevalence was 0.98 (95% CI <0.01-5.9). Significant group differences between PTS and taxi drivers, with respect to potential risk factors for MRSA colonization, were identified as inpatient treatment (p=0.09), chronic respiratory illnesses (p=0.01), and knowingly transporting patients/passengers with MRSA (p=0.03). Conclusion: This study is the first to make data on the MRSA risk of patient transport employees in Hamburg available. The prevalence data are low in all areas and indicate a somewhat low risk of infection. A good infection control at the facilities is highly recommendable and the employees should acquire in-depth knowledge of infection prevention to improve compliance with personal protective measures.

The Emergency Medical Service Microbiome

Emergency medical services (EMS) personnel are an integral component of the health care framework and function to transport patients from various locations to and between care facilities. In addition to physical injury, EMS personnel are expected to be at high risk to acquire and transmit health care-associated infections (HAIs) in the workplace. However, currently, little is known about EMS biosafety risk factors and the epidemiological contribution of EMS to pathogen transmission within and outside the health care sector. Health care facility microbiomes contain diverse bacterial, fungal, and viral pathogens that cause over 1.7 million HAIs each year in the United States alone. While hospital microbiomes have been relatively well studied, there is scant information about EMS infrastructure and equipment microbiomes or the role(s) they play in HAI transmission between health care facilities. We review recent literature investigating the microbiome of ambulances and other EMS service facilities which consistently identify antibiotic-resistant pathogens causing HAIs, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus, and Klebsiella pneumoniae Our review provides evidence that EMS microbiomes are dynamic and important pathogen reservoirs, and it underscores the need for more widespread and in-depth microbiome studies to elucidate patterns of pathogen transmission. We discuss emerging DNA sequencing technologies and other methods that can be applied to characterize and mitigate EMS biosafety risks in the future. Understanding the complex interplay between EMS and hospital microbiomes will provide key insights into pathogen transmission mechanisms and identify strategies to minimize HAIs and community infection.

Screening for Methicillin-resistant Staphylococcus aureus in a residence home for elderly in Germany

BACKGROUND

Since many hospitals report high MRSA colonization rates among elderly patients, and because it has been shown that S. aureus colonization increases with advancing age, there are concerns about the introduction of MRSA into nursing homes by MRSA positive patients discharged from hospital. So far, admission screening and subsequent longitudinal screening in residence homes or screening at time of hospital discharge is not established on a regular base. On the other hand, MRSA is acquired frequently during hospital stay. Therefore, the MRSA status of residents remains unclear at the time of re-admission to the residence home. This study was conducted to evaluate the rate of nasal MRSA carriage among residents and nursing staffs of 2 nursing homes for the elderly, the potential acquisition of MRSA during a hospital stay and the feasibility to perform direct screening tests in nursing homes for elderly.

METHODS

In a study period of 5 months, possibility of active PCR-based screening for MRSA has been tested within 2 residence homes for the elderly, with the obligation to avoid inconvenience to the daily working time and working schedule. Residents and staff members were included in the study and positive test results were confirmed with MRSA culture.

RESULTS

Feasibility of active on site screening in a residence home for the elderly using a rapid PCR method has been confirmed. 154 of 156 residents participated on baseline testing for all current and new admitted residents. In 9 participating residents with former unknown status, nasal carriage with MRSA was confirmed (5.8%). Among 32 documented and eligible movements between the nursing home and the hospital, MRSA could be confirmed after return to the residence home in 2 cases (6.3%). MRSA could also be detected in 1 of 14 participating nursing staff (7.1%).

CONCLUSION

Prevalence of MRSA was in a range that has been observed for nursing homes in Germany in previous studies. Residents can acquire MRSA during a hospital stay so that further spread after re-admission into the nursing home cannot be excluded. This study shows that easy to perform direct screening tests in outpatient facilities for nursing of the elderly are promising tools as part of potential new strategies for transmission and infection control in such facilities. Additional studies are needed to investigate if screening followed by interventional hygiene measures can reduce MRSA transmission and infection in such facilities.

POSAiDA: presence of Staphylococcus aureus/MRSA and Enterococcus/VRE in Danish ambulances. A cross-sectional study

BACKGROUND

Every year approximately one out of ten Danish patients contracts a healthcare associated infection (HAI). Staphylococcus aureus and Enterococcus are prominent in the group of pathogenic bacteria that underlie HAIs, causing unnecessary inconvenience and prolonging hospitalization. Bacterial colonization often occurs due to indirect patient-to-patient transmission, caused by poor hygiene compliance. This study aims to determine the level of contamination with S. aureus/MRSA and Enterococcus/VRE on presumed clean blood pressure cuffs in the Danish ambulances.

METHOD

Blood pressure cuffs were tested for contamination with S. aureus and Enterococcus when being cleaned according to everyday guidelines in this cross-sectional study. Imprints were performed with specific agar plates after cleaning with ethanol wipes. Positive imprints were typed and antibiotic susceptibility was determined.

RESULTS

Both S. aureus and Enterococcus were found on blood pressure cuffs thought to be clean, however, to a limited extent. The average level of contamination by S. aureus was 0.54 CFU per 25 cm(2) (SD 1.98). Minimum and maximum values ranged from 0 to 12 CFU per 25 cm(2) and 10% of the 50 samples were positive. The average level of contamination by Enterococcus was 0.06 CFU per 25 cm(2) (SD 0.42). Minimum and maximum values ranged from 0 to 3 CFU per 25 cm(2) and 2% of the 50 samples were positive. All S. aureus isolates were found to be methicillin susceptible S. aureus (MSSA) and the one Enterococcus isolate was identified as Enterococcus faecalis, negative for vancomycin resistance genes.

CONCLUSION

Staphylococcus aureus and Enterococcus were detectable on equipment thought to be clean. However, all detected bacteria showed susceptibility towards methicillin or vancomycin. Findings of pathogens after cleaning may be due to cross-contamination, improper cleaning and limited effect of the currently used cleaning procedure and are thought to affect the risk of infection. Therefore, we recommend a thorough evaluation of current cleaning procedures as well as increased focus on and further research into hygiene challenges in a prehospital setting. Future studies should be performed in order to demonstrate the level of bacterial contamination in all areas of the medical service, e.g., the ambulance environment, medical equipment, staff uniform and hand hygiene. Furthermore, in order to establish evidence for different cleaning procedures in situ we recommend testing the effect of different cleaning interventions by interventional designs.

Methicillin-resistant Staphylococcus aureus in Ohio EMS Providers: A Statewide Cross-sectional Study

The objective was to determine the nasal carriage prevalence of methicillin-resistant Staphylococcus aureus (MRSA) among emergency medical service (EMS) personnel and the associated risk factors. A cross-sectional study was conducted among Ohio EMS personnel randomly sampled from 84 urban and rural agencies. Surveys assessing demographics, occupational history, health, cohabitation status, and hygiene practice were collected with nasal swabs from those who enrolled. Survey weight adjusted analysis was performed (1) to estimate MRSA nasal carriage prevalence of Ohio EMS providers, and (2) to identify variables associated with MRSA. MRSA was detected in 4.6% (13/280) EMS personnel sampled. After employing a survey-weighted analysis the following risk factors associated with MRSA carriage were identified: those who did not practice frequent hand hygiene after glove use (OR, 10.51; 95% CI, 2.54-43.45; P = 0.0012), living with someone with a recent staphylococcal infection (OR, 9.02; 95% CI, 1.03-78.98; P = 0.0470), and individuals with low frequency of hand washing (< 8 times per shift) (OR, 4.20; 95% CI 1.02-17.27; P = 0.0468). An additional risk factor identified through the logistic regression analysis on the study population was EMS workers with an open wound or skin infection (OR, 6.75; 95% CI, 1.25-36.36; P = 0.0262). However, this was not significant in the survey-weighted analysis. The high prevalence of MRSA in Ohio EMS personnel is both an occupational hazard and patient safety concern. Implementing methods to reinforce CDC guidelines for proper hygiene could decrease MRSA found in the EMS setting. Previous literature suggests that a reduction in MRSA colonization can lead to decreases in transmission and improved health for both patients and personnel.

Prevalence of nosocomial pathogens in German ambulances: the SEKURE study

OBJECTIVE

The increasing prevalence of multidrug resistant bacteria is a problem in the inpatient care setting, and in the emergency care system. The aim of this observational, cross-sectional study was to evaluate the prevalence of pathogens on well-defined surfaces in German ambulances that have been designated as 'ready for service'.

METHODS

After informed consent was obtained, ambulance surfaces were sampled with agar plates for microbiological examination during an unannounced visit. A standardised questionnaire was used to obtain information regarding the disinfection protocols used at each rescue station.

RESULTS

Methicillin resistant staphylococcus aureus contamination was present in 18 sampling surfaces from 11 out of 150 ambulance vehicles (7%) that were designated as ready for service. Contact surfaces directly surrounding patients or staff were most frequently contaminated with pathogens. However, bacterial contamination was not related to annual missions, methods or frequency of disinfection.

CONCLUSIONS

In accordance with previous studies, disinfection and cleaning of areas with direct contact to patients or staff seem to be the most challenging. This should also be reflected in disinfection guidelines and the related continuing education.

Cold atmospheric pressure plasma and decontamination. Can it contribute to preventing hospital-acquired infections?

Healthcare-associated infections (HCAIs) affect ∼4.5 million patients in Europe alone annually. With the ever-increasing number of 'multi-resistant' micro-organisms, alternative and more effective methods of environmental decontamination are being sought as an important component of infection prevention and control. One of these is the use of cold atmospheric pressure plasma (CAPP) systems with clinical applications in healthcare facilities. CAPPs have been shown to demonstrate antimicrobial, antifungal and antiviral properties and have been adopted for other uses in clinical medicine over the past decade. CAPPs vary in their physical and chemical nature depending on the plasma-generating mechanism (e.g. plasma jet, dielectric barrier discharge, etc.). CAPP systems produce a 'cocktail' of species including positive and negative ions, reactive atoms and molecules (e.g. atomic oxygen, ozone, superoxide and oxides of nitrogen), intense electric fields, and ultraviolet radiation (UV). The effects of these ions have been studied on micro-organisms, skin, blood, and DNA; thus, a range of possible applications of CAPPs has been identified, including surface decontamination, wound healing, biofilm removal, and even cancer therapy. Here we evaluate plasma devices, their applications, mode of action and their potential role specifically in combating HCAIs on clinical surfaces.

The uses and abuses of rapid bioluminescence-based ATP assays

Bioluminescence-based ATP testing of solid surfaces has become well established in the food processing industry as part of general hazard analysis and critical control points (HACCP) measures. The rise in healthcare associated infections (HAIs) at the turn of the century focussed attention on the environment as a potential reservoir of the agents responsible for such infections. In response to the need for objective methods of assessing the efficiency of cleaning in healthcare establishments and for rapid methods for detecting the presence of the pathogens responsible for HAIs, it was proposed that ATP testing of environmental surfaces be introduced. We examine the basis behind the assumptions inherent in these proposals. Intracellular ATP levels are shown to vary between microbial taxa and according to environmental conditions. Good correlations between microbial numbers and ATP levels have been obtained under certain specific conditions, but never within healthcare settings. Notwithstanding, ATP testing may still have a role in providing reassurance that cleaning regimes are being carried out satisfactorily. However, ATP results should not be interpreted as surrogate indicators for the presence of microbial pathogens.