Stephanie J. Dancer

Importance of the environment in meticillin-resistant Staphylococcus aureus acquisition: the case for hospital cleaning

In the UK, we continue to debate the importance of hospital cleaning in relation to increasing numbers of patients acquiring meticillin-resistant Staphylococcus aureus (MRSA). However, there is little direct evidence for the effectiveness of cleaning because it has never been afforded scientific status. Hospital hygiene is usually assessed visually, but this does not necessarily correlate with microbiological risk. A more robust case for hospital cleaning can be presented by considering the evidence for all the stages of the staphylococcal transmission cycle between human beings and their environment. Cleaning has already been accepted as an important factor in the control of other hardy environmental pathogens, such as Clostridium difficile, vancomycin-resistant enterococci, norovirus, and Acinetobacter spp. This Review will show why the removal of dirt might have more impact on the control of MRSA than previously thought. Introduction of additional cleaning services is easier than improvements in hand-hygiene compliance.

Measuring the effect of enhanced cleaning in a UK hospital: a prospective cross-over study

BackgroundIncreasing hospital-acquired infections have generated much attention over the last decade. There is evidence that hygienic cleaning has a role in the control of hospital-acquired infections. This study aimed to evaluate the potential impact of one additional cleaner by using microbiological standards based on aerobic colony counts and the presence of Staphylococcus aureus including meticillin-resistant S. aureus.MethodsWe introduced an additional cleaner into two matched wards from Monday to Friday, with each ward receiving enhanced cleaning for six months in a cross-over design. Ten hand-touch sites on both wards were screened weekly using standardised methods and patients were monitored for meticillin-resistant S. aureus infection throughout the year-long study. Patient and environmental meticillin-resistant S. aureus isolates were characterised using molecular methods in order to investigate temporal and clonal relationships.ResultsEnhanced cleaning was associated with a 32.5% reduction in levels of microbial contamination at hand-touch sites when wards received enhanced cleaning (P < 0.0001: 95% CI 20.2%, 42.9%). Near-patient sites (lockers, overbed tables and beds) were more frequently contaminated with meticillin-resistant S. aureus/S. aureus than sites further from the patient (P = 0.065). Genotyping identified indistinguishable strains from both hand-touch sites and patients. There was a 26.6% reduction in new meticillin-resistant S. aureus infections on the wards receiving extra cleaning, despite higher meticillin-resistant S. aureus patient-days and bed occupancy rates during enhanced cleaning periods (P = 0.032: 95% CI 7.7%, 92.3%). Adjusting for meticillin-resistant S. aureus patient-days and based upon nine new meticillin-resistant S. aureus infections seen during routine cleaning, we expected 13 new infections during enhanced cleaning periods rather than the four that actually occurred. Clusters of new meticillin-resistant S. aureus infections were identified 2 to 4 weeks after the cleaner left both wards. Enhanced cleaning saved the hospital £30,000 to £70,000.ConclusionIntroducing one extra cleaner produced a measurable effect on the clinical environment, with apparent benefit to patients regarding meticillin-resistant S. aureus infection. Molecular epidemiological methods supported the possibility that patients acquired meticillin-resistant S. aureus from environmental sources. These findings suggest that additional research is warranted to further clarify the environmental, clinical and economic impact of enhanced hygienic cleaning as a component in the control of hospital-acquired infection.

Finding a benchmark for monitoring hospital cleanliness

This study evaluated three methods for monitoring hospital cleanliness. The aim was to find a benchmark that could indicate risk to patients from a contaminated environment. We performed visual monitoring, ATP bioluminescence and microbiological screening of five clinical surfaces before and after detergent-based cleaning on two wards over a four-week period. Five additional sites that were not featured in the routine domestic specification were also sampled. Measurements from all three methods were integrated and compared in order to choose appropriate levels for routine monitoring. We found that visual assessment did not reflect ATP values nor environmental contamination with microbial flora including Staphylococcus aureus and meticillin-resistant S. aureus (MRSA). There was a relationship between microbial growth categories and the proportion of ATP values exceeding a chosen benchmark but neither reliably predicted the presence of S. aureus or MRSA. ATP values were occasionally diverse. Detergent-based cleaning reduced levels of organic soil by 32% (95% confidence interval: 16-44%; P<0.001) but did not necessarily eliminate indicator staphylococci, some of which survived the cleaning process. An ATP benchmark value of 100 relative light units offered the closest correlation with microbial growth levels <2.5 cfu/cm(2) (receiver operating characteristic ROC curve sensitivity: 57%; specificity: 57%). In conclusion, microbiological and ATP monitoring confirmed environmental contamination, persistence of hospital pathogens and measured the effect on the environment from current cleaning practices. This study has provided provisional benchmarks to assist with future assessment of hospital cleanliness. Further work is required to refine practical sampling strategy and choice of benchmarks.

How antibiotics can make us sick: the less obvious adverse effects of antimicrobial chemotherapy

Antimicrobial agents are associated with side-effects, which are usually tolerated because the benefits of treatment outweigh the toxic effects. Clinicians know about these side-effects but are less likely to understand additional adverse events, such as the overgrowth of resistant microorganisms. Overgrowth can itself precipitate a secondary infection, which can be more difficult to treat. Resistant organisms then spread to other patients and the environment, and contribute to increasing antimicrobial resistance worldwide. Organisms exposed to antibiotics undergo molecular changes that might enhance virulence. Enhanced pathogenicity would affect patients, particularly if the organism is also multiply resistant. Clinicians have a responsibility to select the correct antibiotic as soon as they have diagnosed infection, but an absence of microbiological understanding and ignorance of the potential environmental effects have contributed to inappropriate prescribing. The less obvious results of antimicrobial consumption probably go unrecognised in routine clinical care.

Controlling Hospital-Acquired Infection: Focus on the Role of the Environment and New Technologies for Decontamination

SUMMARY There is increasing interest in the role of cleaning for managing hospital-acquired infections (HAI). Pathogens such as vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), multiresistant Gram-negative bacilli, norovirus, and Clostridium difficile persist in the health care environment for days. Both detergent- and disinfectant-based cleaning can help control these pathogens, although difficulties with measuring cleanliness have compromised the quality of published evidence. Traditional cleaning methods are notoriously inefficient for decontamination, and new approaches have been proposed, including disinfectants, steam, automated dispersal systems, and antimicrobial surfaces. These methods are difficult to evaluate for cost-effectiveness because environmental data are not usually modeled against patient outcome. Recent studies have reported the value of physically removing soil using detergent, compared with more expensive (and toxic) disinfectants. Simple cleaning methods should be evaluated against nonmanual disinfection using standardized sampling and surveillance. Given worldwide concern over escalating antimicrobial resistance, it is clear that more studies on health care decontamination are required. Cleaning schedules should be adapted to reflect clinical risk, location, type of site, and hand touch frequency and should be evaluated for cost versus benefit for both routine and outbreak situations. Forthcoming evidence on the role of antimicrobial surfaces could supplement infection prevention strategies for health care environments, including those targeting multidrug-resistant pathogens.

Approaching zero : temporal effects of a restrictive antibiotic policy on hospital-acquired Clostridium difficile, extended-spectrum β-lactamase-producing coliforms and meticillin-resistant Staphylococcus aureus

A restrictive antibiotic policy banning routine use of ceftriaxone and ciprofloxacin was implemented in a 450-bed district general hospital following an educational campaign. Monthly consumption of nine antibiotics was monitored in defined daily doses (DDDs) per 1000 patient-occupied bed-days (1000 pt-bds) 9 months before until 16 months after policy introduction. Hospital-acquired Clostridium difficile, meticillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase (ESBL)-producing coliform cases per month/1000 pt-bds were identified and reviewed throughout the hospital. Between the first and final 6 months of the study, average monthly consumption of ceftriaxone reduced by 95% (from 46.213 to 2.129 DDDs/1000 pt-bds) and that for ciprofloxacin by 72.5% (109.804 to 30.205 DDDs/1000 pt-bds). Over the same periods, hospital-acquisition rates for C. difficile reduced by 77% (2.398 to 0.549 cases/1000 pt-bds), for MRSA by 25% (1.187 to 0.894 cases/1000 pt-bds) and for ESBL-producing coliforms by 17% (1.480 to 1.224 cases/1000 pt-bds). Time-lag modelling confirmed significant associations between ceftriaxone and C. difficile cases at 1 month (correlation 0.83; P<0.005), and between ciprofloxacin and ESBL-producing coliform cases at 2 months (correlation 0.649; P=0.002). An audit performed 3 years after the policy showed sustained reduction in C. difficile rates (0.259 cases/1000 pt-bds), with additional decreases for MRSA (0.409 cases/1000 pt-bds) and ESBL-producing coliforms (0.809 cases/1000 pt-bds). In conclusion, banning two antibiotics resulted in an immediate and profound reduction in hospital-acquired C. difficile, with possible longer-term effects on MRSA and ESBL-producing coliform rates. Antibiotic stewardship is fundamental in the control of major hospital pathogens.

Monitoring environmental cleanliness on two surgical wards

Ten hand-touch sites were screened weekly on two surgical wards over two consecutive six-month periods. The results were analysed using hygiene standards, which specify (i) an aerobic colony count (ACC) > 2.5 cfu/cm2, and (ii) presence of coagulase-positive staphylococci, as hygiene failures. Sites most often failing the standards were beds and hoist (64%: 33 of 52 weeks), bedside lockers (62%: 32 of 52) and overbed tables (44%: 23 of 52). Methicillin-susceptible/resistant Staphylococcus aureus (MSSA/MRSA) were more often recovered from lockers, overbed tables and beds. Recovery of MSSA/MRSA at any site was significantly associated with an ACC > 2.5 cfu/cm2 from that site (p = 0.001; OR: 3.35 [95% CI 1.79, 6.28]). In addition, total ACCs > 2.5 cfu/cm2 each week were significantly associated with weekly bed occupancies > 95% (p = 0.0004; OR: 2.94 [95% CI 1.44, 6.02]). Higher microbial growth levels from hand-touch sites reflect weekly bed occupancies and indicate a risk for both resistant and susceptible S. aureus. These organisms are more likely to be recovered from near-patient sites on the ward.

Are hygiene standards useful in assessing infection risk

BACKGROUND We monitored the surface level cleanliness in a 5-bed surgical intensive care unit (SICU) over a 10-week period to evaluate proposed hygiene standards. METHODS Ten environmental sites within the SICU were sampled twice weekly, along with collection of clinical and patient activity data. The standards designate aerobic colony counts (ACCs) > 2.5 colony-forming units/cm(2) from hand-touch sites and the presence of Staphylococcus aureus as indicating hygiene failure. RESULTS Nearly 25% of the 200 samples analyzed did not meet the standards, mostly from hand-touch sites on curtains, beds, and medical equipment. The total number of failures each week was associated with bed occupancy (P = .04), with a trend toward association with SICU-acquired infection (P = .11). Environmental S aureus was associated with the proportion of beds occupied (P = .02). Indistinguishable genotypes were found between patient and environmental staphylococci, with time scales supporting staphylococcal transmission in both directions. CONCLUSIONS Hygiene standards based on microbial growth levels and the presence of S aureus reflect patient activity and provide a means to risk-manage infection. They also expose a staphylococcal reservoir that could represent a more tangible risk to patients. Standards for surface level cleanliness merit further evaluation.

Risk of Organism Acquisition from Prior Room Occupants: A Systematic Review and Meta-Analysis

A systematic review and meta-analysis was conducted to determine the risk of pathogen acquisition for patients associated with prior room occupancy. The analysis was also broadened to examine any differences in acquisition risk between Gram-positive and Gram-negative organisms. A search using Medline/PubMed, Cochrane and CINHAL yielded 2577 citations between 1984 and 2014. Reviews were assessed in accordance with the international prospective register of systematic reviews (PROSPERO). Just seven articles met the inclusion criteria, namely: (a) papers were peer reviewed, (b) pathogen acquisition prevalence rates were reported, (c) articles were written in English; and (d) had minimal or no risk of bias based on the Newcastle-Ottawa Scale (NOS). One study was an extension of a previous study and was discarded. Employing NOS provided little difference between the studies, with five studies receiving eight-star and two studies receiving seven-star ratings, respectively. Overall, pooled acquisition odds ratio for study pathogens (meticillin-resistant Staphylococcus aureus; vancomycin-resistant enterococcus; Clostridium difficile; acinetobacter; extended-spectrum β-lactamase-producing coliforms; pseudomonas) was 2.14 [95% confidence interval (CI): 1.65-2.77]. When comparing data between Gram-positive and Gram-negative organisms, the pooled acquisition odds ratio for Gram-negatives was 2.65 (95% CI: 2.02-3.47) and 1.89 (95% CI: 1.62-2.21) for Gram positives. The findings have important implications for infection control professionals, environmental cleaning services and patients, since current practices fail to adequately reduce acquisition risk. Although there may be non-preventable sources of acquisition, revised practices require collaborative work between all responsible staff in order to reduce this risk to a minimum.

Considering the introduction of universal MRSA screening

More and more hospitals are introducing universal screening for meticillin-resistant Staphylococcus aureus (MRSA). As with many other interventions imposed in the name of infection control, the evidence for benefit remains controversial. Despite this, screening has aroused political interest and has now become mandatory in some countries. This Leader examines the implications of introducing universal screening for MRSA. In addition to resource requirements, there are practical difficulties and consequences that may not have been fully considered. These include: staff recruitment and working time arrangements in the laboratory; specificity and sensitivity of selected screening sites and laboratory methods; lack of isolation facilities on the wards; timely and continuing management of MRSA-infected and/or -colonised patients; and ethical issues raised by screening patients without considering the role of colonised staff. Furthermore, the focus on MRSA promotes undue emphasis of its importance, which could facilitate legal interest. We should remember that it is the precipitant actions from finding a new MRSA patient that aids control, not the simple act of screening by itself. There is no doubt that universal screening should be explored as a mechanism for controlling MRSA, but more evidence is required before it becomes routine.