The benefits of surface disinfection

Investigating surface area and recovery efficiency of healthcare-associated pathogens to optimize composite environmental sampling

Hospital surfaces are known to contribute to the spread of healthcare-associated antimicrobial pathogens. Environmental sampling can help locate reservoirs and determine intervention strategies, although sampling and detection can be labor intensive. Composite approaches may help reduce time and costs associated with sampling and detection. We investigated optimum surface areas for sampling antimicrobial-resistant organisms (AROs) with a single side of cellulose sponge, created theoretical composites (TC) by adding recovery results from multiple optimum areas, then compared the TC to the standard Centers for Disease Control and Prevention sampling method (one sponge using all sides, whole tool; (WT)). Five AROs were evaluated: carbapenemase-producing KPC+ Klebsiella pneumoniae (KPC), Acinetobacter baumannii (AB), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis (VRE) and Clostridioides difficile spores (CD). Steel coupons comprising four surface areas (323; 645; 1,290 and 2,258 cm2) were inoculated, dried, and sampled with one sampling pass using the larger side (face) or the smaller side (edge) of a pre-moistened cellulose sponge tool. Based on the optimum areas determined for each organism, composite areas were 1,290 cm2 for MRSA and VRE, 1,936 cm2 for AB, 2,580 cm2 for CD spores and 3,870 cm2 for KPC. Total colony forming units (CFU) recovered using a composite approach was greater or comparable than using multiple WT samplings (over the same area as the composite) for MRSA, VRE and AB (130%; 144% and 95%) yet less than if using multiple WT samplings for KP and CD (47% and 66%). We propose a conservative composite sampling strategy if the target organism is unknown; 323 cm2 sampling area for each of the four sides of the sponge, (1290 cm2 total). The conservative composite sampling strategy improved the recovery of KP (from 47% to 85% of multiple WT samplings), while MRSA, VRE, AB and CD (131%; 144%; 97% and 66%) remained within 5% to that of the optimum area TC.

Decontamination of Fused-Silica Surfaces by UVC Irradiation as Potential Application on Touchscreens

The contamination of surfaces by antibiotic-resistant pathogens presents an escalating challenge, especially on touchscreens in public settings such as hospitals, airports, and means of transport. Traditional chemical cleaning agents are often ineffective and leave behind harmful residues. Thus, the application of optical radiation is gaining relevance as a rapid, effective, and environmentally friendly disinfection method. This study examines the contamination of publicly accessible touchscreens and the efficacy of an irradiation approach for the radiation disinfection of microorganisms on quartz surfaces with UVC LEDs. In this setup, the LED radiation is laterally coupled into a quartz plate that serves as cover glass of a simplified touchscreen model. The process allows for the irradiation of microorganisms on the surface, without the user being exposed to hazardous radiation. To assess the efficacy of the disinfection process, a range of bacteria, mostly ESKAPE surrogates, such as Staphylococcus carnosus, Acinetobacter kookii, Escherichia coli, Enterococcus mundtii, and additionally Micrococcus luteus, were spread over a quartz plate with a homebuilt nebulization system. After operating the side-mounted LEDs for 30 s, a reduction in all bacteria except M. luteus by more than three orders of magnitude was observed. In the case of M. luteus, a significant reduction was achieved after 60 s (p < 0.05). This result demonstrates the potential of side-mounted UVC LEDs for rapid disinfection of touchscreens between two users and thus for reducing the spread of pathogens without irradiating humans.

Surface decontamination effectiveness at the "Université des Montagnes" Teaching Hospital: Monitoring in the biomedical analysis laboratory

Background

Many infections in healthcare facilities are associated with the microbiological quality of the work environment, generally due to poor sanitation.

Aim

In order to evaluate the effectiveness of a decontamination protocol (cleaning + disinfection) applied at the "Université des Montagnes" Teaching Hospital, the present study assessed the variation of bacterial loads on surfaces subsequent to decontamination. Susceptibility of bacteria to disinfectants was also evaluated in the same frame.

Methodology

This work was conducted with an adjusted bacterial detection/enumeration and susceptibility test protocols and standard bacterial identification protocols. Sampling on surfaces was performed by wet swabbing before cleaning, between cleaning and disinfection and after disinfection.

Results

Major findings revealed the predominance of Staphylococcus (75.5%) on target surfaces. High bacterial loads recorded on these surfaces before decontamination became undetectable after cleaning with the detergent "Pax lemon". The majority of isolates (98%) were susceptible to the disinfectants tested, (Surfanios® 0.25% and sodium hypochlorite 0.12%).

Conclusion

Overall, these findings indicated process effectiveness on the subjected bacterial populations and suggest the use of either Surfanios® (0.25%) or sodium hypochlorite (0.12%) for work surfaces hygiene, justifying the use of these products in this department for surface decontamination. Also, cleaning with the detergent "Pax lemon" and disinfection with sodium hypochlorite may be sufficient for the types of surfaces subjected in the present research.

Evaluation of an Ultraviolet C (UVC) Light-Emitting Device for Disinfection of High Touch Surfaces in Hospital Critical Areas

Implementation of environmental cleaning and disinfection has been shown to reduce the incidences of healthcare-associated infections. The effect of an enhanced strategy for terminal room disinfection, applying the pulsed xenon-based ultraviolet light no-touch disinfection systems (PX-UVC) after the current standard operating protocol (SOP) was evaluated. In a teaching hospital, the effectiveness in reducing the total bacterial count (TBC) and in eliminating high-concern microorganisms was assessed on five high-touch surfaces in different critical areas, immediately pre- and post-cleaning and disinfection procedures (345 sampling sites). PX-UVC showed only 18% (15/85) of positive samples after treatment compared to 63% (72/115) after SOP. The effectiveness of PX-UVC was also observed in the absence of manual cleaning and application of a chemical disinfectant. According to the hygienic standards proposed by the Italian Workers Compensation Authority, 9 of 80 (11%) surfaces in operating rooms showed TBC ≥15 CFU/24 cm2 after the SOP, while all samples were compliant applying the SOP plus PX-UVC disinfection. Clostridium difficile (CD) spores and Klebsiella pneumoniae (KPC) were isolated only after the SOP. The implementation of the standard cleaning and disinfection procedure with the integration of the PX-UVC treatment had effective results in both the reduction of hygiene failures and in control environmental contamination by high-concern microorganisms.

Starch-based polyurethane/CuO nanocomposite foam: Antibacterial effects for infection control

In the present study, a new method for the synthesis of the open cell flexible polyurethane foams (PUFs) was developed by using starch powder and the modification of closed cell foam formulation. Starch is the second largest polymeric carbohydrate as a macromolecule on this planet with a large number of glucose units. Copper oxide nanoparticles (CuO NPs) were synthesized by thermal degradation method at different temperatures of 400, 600 and 800 °C as antimicrobial agents. The antimicrobial activity of CuO NPs and commercial CuO powder against the main causes of hospital infections were tested. CuO₆₀₀ was the most effective antimicrobial agent and enhanced polymer matrix tensile strength with starch powder as new polyurethane foams (PUFs) cell opener with high tensile strength. The effects of parameters on tensile strength were optimized using response surface methodology (RSM). CuO NPs and PUF had optimal conditions and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Foam synthesized at the optimal conditions had an open cell structure with high tensile strength and efficient antimicrobial activity that made them suitable to be used as an antimicrobial hospital mattress to control hospital infections.

Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines

Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.

Surface Disinfectants for Burn Units Evaluated by a New Double Method, Using Microorganisms Recently Isolated From Patients, on a Surface Germ-Carrier Model

Assessment methods of surface disinfection based on international standards (Environmental Protection Agency, European Norms, etc) do not correspond to hospital reality. New evaluation methods of surfaces disinfection are proposed to choose the most suitable disinfectant to act against clinically relevant microorganisms detected on the surfaces of burn units. 1) "Immediate effect": 6 products were compared using a glass germ-carrier and 20 recently isolated microorganisms from different patients in the intensive care units. Disinfectants were applied with microfiber cloths. Log10 reductions were calculated for colony forming units produced after 15 minutes of disinfectant application. 2) "Residual effect": the glass germ-carriers were previously impregnated with one of the studied disinfectants. After a 30-minute wait period, they were then contaminated with 1 microorganism (from the 20 above-mentioned). After 15 minutes, the disinfectant was inhibited and the log10 reduction of colony forming units was assessed. The immediate effect (disinfection and microorganism dragging and transferring from the surface to the cloth) produced complete elimination of the inoculums for all products used except one (a diluted quaternary ammonium). The average residual effect found on the 20 microorganisms was moderate: 2 to 3 log10 colony forming unit reduction with chlorine dioxide or 0.5% chlorhexidine (and lower with the other products), obtaining surfaces refractory to recontamination, at least, during 30 minutes. Two tests should be performed before advising surface disinfectant: 1) direct effect and 2) residual efficacy. These characteristics should be considered when a new surface disinfectant is chosen. Chlorine dioxide has a similar or better direct effect than sodium hypochlorite and a similar residual effect than chlorhexidine.

Assessment of the Overall and Multidrug-Resistant Organism Bioburden on Environmental Surfaces in Healthcare Facilities

OBJECTIVE To determine the typical microbial bioburden (overall bacterial and multidrug-resistant organisms [MDROs]) on high-touch healthcare environmental surfaces after routine or terminal cleaning. DESIGN Prospective 2.5-year microbiological survey of large surface areas (>1,000 cm2). SETTING MDRO contact-precaution rooms from 9 acute-care hospitals and 2 long-term care facilities in 4 states. PARTICIPANTS Samples from 166 rooms (113 routine cleaned and 53 terminal cleaned rooms). METHODS Using a standard sponge-wipe sampling protocol, 2 composite samples were collected from each room; a third sample was collected from each Clostridium difficile room. Composite 1 included the TV remote, telephone, call button, and bed rails. Composite 2 included the room door handle, IV pole, and overbed table. Composite 3 included toileting surfaces. Total bacteria and MDROs (ie, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci [VRE], Acinetobacter baumannii, Klebsiella pneumoniae, and C. difficile) were quantified, confirmed, and tested for drug resistance. RESULTS The mean microbial bioburden and range from routine cleaned room composites were higher (2,700 colony-forming units [CFU]/100 cm2; ≤1-130,000 CFU/100 cm2) than from terminal cleaned room composites (353 CFU/100 cm2; ≤1-4,300 CFU/100 cm2). MDROs were recovered from 34% of routine cleaned room composites (range ≤1-13,000 CFU/100 cm2) and 17% of terminal cleaned room composites (≤1-524 CFU/100 cm2). MDROs were recovered from 40% of rooms; VRE was the most common (19%). CONCLUSIONS This multicenter bioburden summary provides a first step to determining microbial bioburden on healthcare surfaces, which may help provide a basis for developing standards to evaluate cleaning and disinfection as well as a framework for studies using an evidentiary hierarchy for environmental infection control. Infect Control Hosp Epidemiol 2016;1426-1432.

Evaluation of a pulsed xenon ultraviolet light device for isolation room disinfection in a United Kingdom hospital

BACKGROUND

Pathogen transmission from contaminated surfaces can cause hospital-associated infections. Although pulsed xenon ultraviolet (PX-UV) light devices have been shown to decrease hospital room bioburden in the United States, their effectiveness in United Kingdom (UK) hospitals is less understood.

METHODS

Forty isolation rooms at the Queens Hospital (700 beds) in North London, UK, were sampled for aerobic bacteria after patient discharge, after manual cleaning with a hypochlorous acid-troclosene sodium solution, and after PX-UV disinfection. PX-UV device efficacy on known organisms was tested by exposing inoculated agar plates in a nonpatient care area. Turnaround times for device usage were recorded, and a survey of hospital staff for perceptions of the device was undertaken.

RESULTS

After PX-UV disinfection, the bacterial contamination measured in colony forming units (CFU) decreased by 78.4%, a 91% reduction from initial bioburden levels prior to terminal cleaning. PX-UV exposure resulted in a 5-log CFU reduction for multidrug-resistant organisms (MDROs) on spiked plates. The average device turnaround time was 1 hour, with minimal impact on patient throughput. Ward staff were enthusiastic about device deployment, and device operators reported physical comfort in usage.

CONCLUSIONS

PX-UV use decreased bioburden in patient discharge rooms and on agar plates spiked with MDROs. The implementation of the PX-UV device was well received by hospital cleaning and ward staff, with minimal disruption to patient flow.

Contamination of environmental surfaces by methicillin-resistant Staphylococcus aureus (MRSA) in rooms of inpatients with MRSA-positive body sites

Methicillin-resistant Staphylococcus aureus (MRSA) can contaminate environmental surfaces that are frequently touched by the hands of patients with MRSA colonization/infection. There have been many studies in which the presence or absence of MRSA contamination was determined but no studies in which MRSA contamination levels were also evaluated in detail. We evaluated MRSA contamination of environmental surfaces (overbed tables, bed side rails, and curtains) in the rooms of inpatients from whom MRSA was isolated via clinical specimens. We examined the curtains within 7–14 days after they had been newly hung. The environmental surfaces were wiped using gauze (molded gauze for wiping of surface bacteria; 100% cotton, 4 cm × 8 cm) moistened with sterile physiological saline. The MRSA contamination rate and mean counts (range) were 25.0% (6/24 samples) and 30.6 (0–255) colony-forming units (cfu)/100 cm², respectively, for the overbed tables and 31.6% (6/19 samples) and 159.5 (0–1620) cfu/100 cm², respectively, for the bed side rails. No MRSA was detected in 24 curtain samples. The rate of MRSA contamination of environmental surfaces was high for the overbed tables and bed side rails but low for the curtains. Therefore, at least until the 14th day of use, frequent disinfection of curtains may be not necessary.

Videocâmeras em biotérios de experimentação: importante ferramenta no controle da contaminação ambiental na microbiota de camundongos

O objetivo do presente estudo foi verificar a influência da contaminação ambiental na microbiota dos animais utilizados em experimentação, usando-se videocâmera como ferramenta de controle, a partir da comparação de dois biotérios de experimentação, sendo um protegido com presença de videocâmeras (A) e o outro não (B), quanto ao padrão microbiológico dos camundongos. Para os testes bacteriológicos, foram utilizadas amostras de 222 animais do biotério A e 236 do biotério B; para os testes virológicos, 119 do biotério A e 236 do biotério B; já para os exames parasitológicos, 158 do biotério A e 316 do biotério B. Os dados foram submetidos à análise descritiva e ao teste do Qui-quadrado. Verificou-se uma maior ocorrência de microrganismos e de parasitas no biotério não protegido pelas videocâmeras. Klebsiella pneumoniae, Pasteurella sp. e Pseudomonas sp. foram encontradas nos animais de ambos os biotérios, ao passo que vírus e parasitos só foram detectados nos animais no biotério não protegido. Dentre os vírus, nos animais infectados, o de maior ocorrência foi o Vírus da Hepatite de Camundongos (MHV) e, dentre os parasitos, o de maior ocorrência foi Syphacia sp. Concluiu-se que o biotério protegido foi capaz de garantir padrões microbiológicos mais adequados para a experimentação animal, que as videocâmeras são importantes ferramentas de controle e que a prática da biossegurança deve ser constante nas instituições de pesquisa.

Microbial colonization of electrocardiographic telemetry systems before and after cleaning

BACKGROUND

Nosocomial infections caused by multidrug-resistant organisms are commonly associated with longer hospital stays up to 12 to 18 days and annual estimated costs of $5.7 billion to $6.8 billion. One common mode of transmission is cross-contamination between patients and providers via surface contaminants on devices such as telemetry systems.

OBJECTIVES

To determine the effect of a cleaning protocol on colonization of surface contaminants on electrocardiographic telemetry systems in 4 cardiovascular step-down units and to compare colonization in medical vs surgical units.

METHODS

A prospective, randomized, case-controlled study (the Descriptive Evaluation of Electrocardiographic Telemetry Pathogens [DEET] study) was designed to evaluate microbial colonization on telemetry systems before and after cleaning with sodium hypochlorite wipes. Each randomly selected telemetry system served as its own control. Nurses used a standardized culture technique recommended by personnel in infection control. Colonization before and after cleaning was analyzed by using the McNemar test and frequency tables. A standard cost-comparison analysis was conducted.

RESULTS

A total of 30 telemetry systems in medical units and 29 in surgical units were evaluated; 41 telemetry systems (69%) were colonized before the intervention, and 14 (24%) were colonized after it (P < .001). Before cleaning, surface organisms were present in 14 instances (35%) in surgical units and in 27 instances (66%) in medical units (P < .001). The cleaning strategy was cost-effective.

CONCLUSIONS

The cleaning intervention was effective, and cost-comparison analysis supported implementing a cleaning strategy for reusable leads rather than investing in disposable leads.

The role of surface disinfection in infection prevention

Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.

Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.

Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.

Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

String capsule endoscopy for screening and surveillance of esophageal varices in patients with cirrhosis

BACKGROUND

EGD is the gold standard for the screening and surveillance of esophageal varices. A less invasive, safer and sedationless alternative procedure is needed.

OBJECTIVE

To assess the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) as well as the beyond the chance agreement (kappa index), of string capsule endoscopy (SCE) in the diagnosis of esophageal varices.

METHODS

Cirrhotic patients underwent string capsule endoscopy (SCE) and EGD for screening and surveillance purposes. Varices were graded at EGD and SCE as small, medium and large. Descriptors at SCE were added as follows: PLUS, for the presence of red wale signs or, MINUS for their absence, irrespective of the estimated variceal size. Clinically significant varices were defined by their size (medium/large at either EGD or SCE) and/or, the PLUS descriptor irrespective of the estimated size at SCE. Sensitivity, specificity, PPV, NPV, accuracy and kappa index were calculated. Procedure time, procedure-related discomfort and patient's preference were documented.

RESULTS

100 patients (33 for screening and 67 for surveillance) were enrolled. The sensitivity and specificity of SCE for clinically significant varices when using the PLUS/MINUS descriptors were 82% and 90%, respectively with a PPV of 84% and NPV of 89% and a kappa of 0.73.

CONCLUSION

String capsule endoscopy had an acceptable sensitivity and specificity for the diagnosis of clinically significant esophageal varices but the lack of air insufflation still hampers its correlation with the grading used with EGD.

Reduction of bacterial surface contamination in the hospital environment by application of a new product with persistent effect

The benefit of routine surface disinfection in hospitals has been discussed. In this study we have investigated a new product, Appeartex. After application on surfaces a remnant effect is achieved due to the positive charge of the active molecule. We studied the persistent effect of Appeartex one day after application in both an experimental study in the laboratory and a field study in a hospital ward. Surfaces of bedside tables were investigated. In the experimental study, large inocula of >or=10(6)cfu of S. aureus or enterococci were inoculated on to well-defined areas which had been treated/not treated with Appeartex. One hour later, samples were taken with a swab rinse technique. A reduction in the number of viable bacteria in the magnitude 10-10(3) cfu was seen due to the effect of Appeartex. In the field study the effect on naturally occurring low level contamination was studied. Defined surfaces on bedside tables used by patients were treated/not treated with Appeartex. One day later, samples were taken with contact agar plates and with a new swab method using two sequential nylon flocked swabs. Significantly fewer bacteria were found on Appeartex-treated surfaces compared with untreated surfaces. The median counts on Appeartex-treated surfaces were 10 cfu/50 cm(2), and on untreated surfaces 20 cfu/50 cm(2). There was no significant difference in the number of bacteria found by culture of samples taken with the contact agar method compared with samples taken using the nylon flocked swab method.

Implementing the MRSA recommendations made by the Commission for Hospital Hygiene and Infection Prevention (KRINKO) of 1999 - current considerations by the DGKH Management Board

In Germany, recommendations on dealing with patients who are colonised with methicillin-resistant S. aureus (MRSA) for the inpatient sector have been published in 1999 by the Commission for Hospital Hygiene and Infection Prevention (KRINKO). Some challenges arise with regard to the practical implementation of the KRINKO recommendations. These challenges do not principally question the benefit of the recommendations but have come into criticism from users. In this commentary the German Society for Hospital Hygiene (DGKH) discusses some controversial issues and adds suggestions for unresolved problems regarding the infection control management of MRSA in healthcare settings.

Activity of a dry mist hydrogen peroxide system against environmental Clostridium difficile contamination in elderly care wards

Clostridium difficile causes serious healthcare-associated infections. Infection control is difficult, due in part to environmental contamination with C. difficile spores. These spores are relatively resistant to cleaning and disinfection. The activity of a dry mist hydrogen peroxide decontamination system (Sterinis) against environmental C. difficile contamination was assessed in three elderly care wards. Initial sampling for C. difficile was performed in 16 rooms across a variety of wards and specialties, using Brazier's CCEY (cycloserine-cefoxitin-egg yolk) agar. Ten rooms for elderly patients (eight isolation and two sluice rooms) were then resampled following dry mist hydrogen peroxide decontamination. Representative isolates of C. difficile were typed by polymerase chain reaction ribotyping. C. difficile was recovered from 3%, 11% and 26% of samples from low, medium and high risk rooms, respectively. In 10 high risk elderly care rooms, 24% (48/203) of samples were positive for C. difficile, with a mean of 6.8 colony-forming units (cfu) per 10 samples prior to hydrogen peroxide decontamination. Ribotyping identified the presence of the three main UK epidemic strains (ribotypes 001, 027 and 106) and four rooms contained mixed strains. After a single cycle of hydrogen peroxide decontamination, only 3% (7/203) of samples were positive (P<0.001), with a mean of 0.4 cfu per 10 samples ( approximately 94% reduction). The Sterinis hydrogen peroxide system significantly reduced the extent of environmental contamination with C. difficile in these elderly care rooms. This relatively quick and user-friendly technology might be a more reliable method of terminally disinfecting isolation rooms, following detergent cleaning, compared to the manual application of other disinfectants.

A pilot study to isolate Staphylococcus aureus and methicillin-resistant S aureus from environmental surfaces in the home

BACKGROUND

The major sources of Staphylococcus aureus, including methicillin-resistant S aureus (MRSA), in the home are colonized or infected individuals and pets, such as cats and dogs; however, the occurrence of MRSA on surfaces in healthy homes is not well documented.

METHODS

A convenience sample comprising 35 homes of health care and non-health care workers, each with a child in diapers and either a cat or dog in the home, was recruited from the Boston area between January and April 2006. In each home, a total of 32 surfaces were sampled in kitchens, bathrooms, and living areas.

RESULTS

S aureus was found in 34 of the 35 homes (97%) and was isolated from all surfaces in 1 or more homes, with the exception of the kitchen chopping board and the child training potty. MRSA was isolated from 9 of 35 homes (26%) and was found on a variety of household surfaces, including the kitchen and bathroom sinks, countertops, kitchen faucet handle, kitchen drain, dish sponge/cloth, dish towel, tub, infant high chair tray, and pet food dish. A positive correlation was indicated for the presence of a cat and the isolation of MRSA from surfaces.

CONCLUSIONS

This study has shown the presence of MRSA at hand-contact surfaces in healthy homes. This provides further evidence for the potential for infection transmission via inanimate surfaces and underscores the need for good hygiene practice in the home.

Microbiologic evaluation of microfiber mops for surface disinfection

BACKGROUND

Recently, health care facilities have started to use a microfiber mopping technique rather than a conventional, cotton string mop to clean floors.

METHODS

The effectiveness of microfiber mops to reduce microbial levels on floors was investigated. We compared the efficacy of microfiber mops with that of conventional, cotton string mops in 3 test conditions (cotton mop and standard wringer bucket, microfiber mop and standard wringer bucket, microfiber system). Twenty-four rooms were evaluated for each test condition. RODAC plates containing D/E Neutralizing Agar were used to assess "precleaning" and "postcleaning" microbial levels.

RESULTS

The microfiber system demonstrated superior microbial removal compared with cotton string mops when used with a detergent cleaner (95% vs 68%, respectively). The use of a disinfectant did not improve the microbial elimination demonstrated by the microfiber system (95% vs 95%, respectively). However, use of disinfectant did significantly improve microbial removal when a cotton string mop was used (95% vs 68%, respectively).

CONCLUSION

The microfiber system demonstrated superior microbial removal compared with cotton string mops when used with a detergent cleaner. The use of a disinfectant did not improve the microbial elimination demonstrated by the microfiber system.

The development of a new three-step protocol to determine the efficacy of disinfectant wipes on surfaces contaminated with Staphylococcus aureus

We developed a three-step protocol to quantify the efficacy of disinfectant wipes, their ability to remove and prevent microbial transfer from surfaces and their overall antimicrobial activity. Meticillin-resistant (MRSA) or -susceptible (MSSA) Staphylococcus aureus (6-7 log(10)cfu) were inoculated onto stainless steel discs with or without organic load and dried. Grapefruit extract-containing test wipes and unmedicated control wipes were used. In step 1, wipes were mechanically rotated against surfaces for 10s at 60rpm, exerting a weight of 100+/-5g. Bacterial removal was assessed by transferring the steel discs to neutraliser, resuspending and counting remaining bacteria. In step 2, bacterial transfer from wipes was assessed by eight consecutive mechanical adpression transfers to agar/neutraliser plates. Step 3 was the measurement of antimicrobial activity by direct inoculation of the wipes for 10s followed by neutralisation and enumeration. Test wipes achieved a significantly higher bacterial cell removal than control wipes on all surfaces (P<0.05). The low bactericidal activity of the wipes (<1 log(10) reduction when directly inoculated) and the subsequent survival of bacteria on the wipes, however, led to repeated microbial transfer when initially high contamination levels were present. There were no differences between MRSA and MSSA in removal, transfer or antimicrobial activity. The three-step method is a useful tool for developing future guidelines to assess the ability of wipes to disinfect surfaces.

Importance of environmental decontamination--a critical view

The level of evidence supporting different disinfection and cleaning procedures performed in healthcare settings worldwide is low. With respect to environmental surfaces, the final assessment of whether use of disinfectants rather than detergents alone reduces nosocomial infection rates in different clinical settings still awaits conclusive study. It must be kept in mind that the effect of surface disinfection is only transient microbial contamination will have reached its former level within a few hours. While resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. avoidance of widespread application, especially in low concentrations and in consumer products. The decontamination ability of the substances used; prevention of resistance; and safety for patients, personnel and the environment; are the cornerstones that interact with each other. Future work should focus on this complex background. Targeted disinfection of environmental surfaces (those frequently touched) is an established component of infection control activities to prevent the spread of nosocomial (multi-resistant) pathogens, but of lesser importance than proper hand hygiene. However, since the use of disinfectants may pose a danger to staff, patients and the environment, prudent use combined with the application of proven safety precautions is important. Since emerging resistant pathogens will challenge healthcare facilities in future even more than today, well-designed studies addressing the role of disinfection in the healthcare-setting are needed.

Bacterial resistance to biocides in the healthcare environment: should it be of genuine concern?

The emergence of bacterial resistance following exposure in healthcare facilities has been a recurrent topic of interest over the last 10 years. The overwhelming and increasing body of evidence from studies in vitro showed that bacteria have an immense capacity to respond to chemical stress brought upon by biocides. Empirically two major types of mechanisms have been described: intrinsic and acquired. However, the increasing documented response from bacteria exposed to biocide in conditions close to those found in practice suggests that intrinsic resistance does not adequately describe bacterial survival mechanisms, and that other terms such as biofilm resistance and environmental resistance would be therefore more appropriate. In addition, such terms are more relevant when describing in-situ conditions. The lack of evidence of bacterial resistance in practice and the inability to correlate emerging bacterial resistance from in-vitro experiments with practical situations is a major drawback when attempting to ascertain whether emerging bacterial resistance in healthcare facilities is of genuine concern. Microbial resistance to high or in-use concentration of biocides has been described in practice, although it remains uncommon. The efficacy of biocides in eliminating bacterial contaminants within healthcare facilities has to be questioned with the widespread and increasing use of products containing low concentrations of biocide or possessing low bactericidal activity, as is the selection of less susceptible bacteria following such exposure.

Patient risk of contact with respiratory pathogens from inanimate surfaces in a cystic fibrosis outpatient clinic. A prospective study over a four-year period

Acquisition of respiratory pathogens such as Pseudomonas aeruginosa (PA) is associated with increased morbidity and mortality in cystic fibrosis (CF). Research on the prevalence of these pathogens on environmental surfaces of a CF Center is scanty, and so far no study has determined what risk CF patients have of coming in contact with them during their visits to the CF Center. This study is aimed at assessing the prevalence of some respiratory pathogens in samples taken systematically during a 4-year period from inanimate surfaces and sinks in a CF Outpatient Clinic, and to estimate the risk that a non-PA colonized CF patient has of contact with PA when visiting the CF Center. Microbiological samples were taken and cultured from the inanimate surfaces and sinks of the Outpatient clinic of a CF Center once a month from 2001 to 2005. Four hundred and sixty environmental specimens were collected: 36.3% were positive for respiratory pathogens (23% of rooms' inert surfaces, 49.5% of sinks). Achromobacter xylosoxidans was found in 0.8% of surface samples. PA was isolated in 22.8% samples. The estimated risk for each non-colonized patient of coming in contact with PA on the surfaces in the Clinic at each visit was 5.4 per thousand (CI95% 0.9-30.1). Genotyping of a sample of environmental PA strains revealed a genetic relation between environmental and clinical isolates in most cases. Micro-organisms relevant for CF patients can be found on inanimate surfaces of a CF Center, although the risk for patients of coming in contact with PA during their visits to the CF center seems low.

The effectiveness of existing and modified cleaning regimens in a Welsh hospital

Hospital cleaning currently has a high media profile. The effectiveness of an existing ward-cleaning regimen was assessed at selected sites over a 14 day period and shown to be highly variable. The cleaning regimen was subsequently modified in two stages, both changes involving a rinse stage and substituting cloths with disposable paper towels. One modification continued using the existing detergent; the other replaced detergent with a quaternary ammonium sanitiser. Both modifications yielded significantly lower and more consistent bacterial counts. Assessment of residual organic soil using adenosine triphosphate (ATP) detection demonstrated that failure rates (measurements exceeding benchmark clean value of 500 relative light units (RLU)) fell from 86-100% after existing cleaning methods, to 0-14% after modified cleaning. Maximum ATP readings fell from 163,870 to 2289 RLU. Incorporating a quaternary ammonium sanitiser into the cleaning regimen produced a further slight, but not significant, improvement in cleaning efficacy. These findings suggest that simple improvements can be made to existing cleaning regimens to increase their efficacy.

Étude de l'efficacité d'un produit détergent désinfectant pour sols et surfaces sur les souches bactériennes isolées à partir de l'environnement hospitalier

We studied the sensitivity of the hospital environmental bacterial strains to Surfanios, which is a detergent and disinfectant product for surfaces. This product is used in our establishment since nearly 10 years. This work which relates to 425 bacterial strains proposes to study the possible evolution of the resistance of the bacteria under the pressure of a product biocide used since many years without the change of active ingredient as recommended in pharmaceutical and agroalimentary industry. We developed a micromethod to study the sensitivity of many bacterial strains simultaneously into a 96 wells microplaque. All the Staphylococcus aureus strains (N = 20) and Staphylococcus with coagulase negative (N = 308) as 78 Acinetobacter sp. strains remain very sensitive to Surfanios according to our study. Target dilution, which is the last dilution not allowing the bacterial growth, is much lower than the manufacturer recommended use dilution. For the Pseudomonas aeruginosa strains tested, target dilution is equal or higher than the dilution of use. Rather than to propose the rotation or the alternation of the products, we recommend the use of Surfanios for the bionettoyage of dry surfaces which might be contaminated by Staphylococcus sp. or Acinetobacter sp. and the use of another product or Surfanios at a higher concentration, active on Pseudomonas sp. to disinfect wet surfaces which are possible reservoirs for the opportunist bacteria of the hydrous flora.

Cellulose acetate containing toluidine blue and rose bengal is an effective antimicrobial coating when exposed to white light

Simple methods of reducing the microbial load on surfaces in hospitals are needed to reduce the risk of hospital-associated infections. Here we report on the ability of a cellulose acetate coating containing the photosensitizers toluidine blue and rose bengal to kill microbes (Staphylococcus aureus, Escherichia coli, Clostridium difficile, a bacteriophage, and Candida albicans) on its surface when illuminated with white light.

Redesign of portable suction equipment cases: an engineering approach to a disinfection problem

BACKGROUND

Patients with tracheostomies carry a case for suctioning supplies. A returned case cultured positive for Staphylococcus aureus even after it had been cleaned with a disinfectant. The purposes of this study were to determine (1) the source of the S aureus and (2) how to provide a microbiologically safe case for the next patient.

METHODS

Reviews of patient and environmental cultures plus pulsed-field gel electrophoresis (PFGE) were used to determine the source of the S aureus. Repeated wiping with various detergents/disinfectants did not remove the S aureus from the case, which could not be immersed for cleaning because of a chipboard component. We designed a case made of denim with a washable synthetic fiber to provide shape. The new cases were purposefully contaminated and laundered and then cultured.

RESULTS

PFGE indicated that the S aureus was from the patient who had most recently used the case. Contamination of the denim case with the original S aureus, followed by laundering, resulted in a case that was free of the S aureus. These results were repeated for other pathogens.

CONCLUSION

Commercially available cases for suction equipment can become contaminated with pathogens from the user and may be difficult to disinfect. By making the case out of washable materials, less expensive cases, which could be readily disinfected, resulted.

Susceptibility of clinical isolates of multiresistant Pseudomonas aeruginosa to a hospital disinfectant and molecular typing

The aim of this study was to evaluate the susceptibility of 35 resistant Pseudomonas aeruginosa clinical isolates to a quaternary ammonium hospital disinfectant. The methodology was the AOAC Use-Dilution Test, with disinfectant at its use-concentration. In addition, the chromosomal DNA profile of the isolates were determined by macro-restriction pulsed field gel electrophoresis (PFGE) method aiming to verify the relatedness among them and the behavior of isolates from the same group regarding the susceptibility to the disinfectant. Seventy one percent of the isolates were multiresistant to antibiotics and 43% showed a reduced susceptibility to the disinfectant. The PFGE methodology detected 18 major clonal groups. We found isolates with reduced susceptibility to the disinfectant and we think that these are worrying data that should be further investigated including different organisms and chemical agents in order to demonstrate that microorganisms can be destroyed by biocide as necessary. We also found strains of the same clonal groups showing different susceptibility to the disinfectant. This is an interesting observation considering that only few works are available about this subject. PFGE profile seems not to be a reliable marker for resistance to disinfectants.

Hospital disinfection: efficacy and safety issues

PURPOSE OF REVIEW

To review recent publications relevant to hospital disinfection (and cleaning) including the reprocessing of medical instruments.

RECENT FINDINGS

The key question as to whether the use of disinfectants on environmental surfaces rather than cleaning with detergents only reduces nosocomial infection rates still awaits conclusive studies. New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents. The safe reprocessing of medical devices requires a well-coordinated approach, starting with proper cleaning. New methods and substances show promising activity for preventing the transmission of prions. Different aspects of virus inactivation have been studied, and the transmissibility, e.g. of norovirus, shows the need for sound data on how different disinfectant classes perform. Biofilms or other forms of surface-adherent organisms pose an extraordinary challenge to decontamination. Although resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. the avoidance of widespread application, especially in low concentrations and in consumer products.

SUMMARY

Chemical disinfection of heat-sensitive instruments and targeted disinfection of environmental surfaces are established components of hospital infection control. To avoid danger to staff, patients and the environment, prudent use as well as established safety precautions are required. New technologies and products should be evaluated with sound methods. As emerging resistant pathogens will challenge healthcare facilities in the future even more than at present, there is a need for well-designed studies addressing the role of disinfection in hospital infection control.