To our knowledge, this is the first study to explore MRSA and C. difficile contamination, concurrently, in both patient rooms and the ward environment of a community hospital, longitudinally. The percentages of exposed patient rooms that were found to be contaminated with MRSA or C. difficile were lower compared to other studies [24–27]. This contrast in results may have been attributed to the number of patient rooms and surfaces investigated in addition to different sampling and culturing methodologies used among the studies.
Surfaces located in rooms with a C. difficile patient had increased odds of being contaminated with C. difficile compared to unexposed and MRSA exposed rooms, an unsurprising result given the potential for infected patients to contaminate their environment and the ability of C. difficile spores to survive in the hospital environment for months . Interestingly, unexposed rooms were also identified as having a large number of surfaces contaminated with MRSA or C. difficile. Previous studies have also reported the presence of these HA pathogens on surfaces located in patient areas not occupied by MRSA or C. difficile patients [25, 27, 28]. Reasons for the extensive contamination of surfaces in unexposed patient rooms may include transfer of pathogens via hands or fomites of staff, patients, and visitors; misclassification of patient rooms due to unidentified colonization status of individuals; or failure of routine cleaning and disinfection practices. Although MRSA and C. difficile are susceptible to the disinfectants used in this facility, a quaternary ammonium compound and bleach, respectively, inadequate cleaning and disinfection practices cannot be excluded. In a multicentre study conducted by Carling and colleagues , only 49.5% (1748/3532) of high touch surfaces located in intensive care units were identified as being clean following terminal cleaning practices. Lastly, rooms housing known MRSA or C. difficile-infected individuals have enhanced cleaning protocols compared to other rooms, as a result, surfaces may not be cleaned as rigorously or as often in unexposed rooms. These data highlight the need for regular and proper cleaning of all hospital areas, not just those known to house patients with pathogens such as MRSA and C. difficile.
In patient rooms, the identification of MRSA or C. difficile on overbed tables, privacy curtains, and televisions is consistent with the literature [24, 30–36], and presumably, any hand contact surface is at some degree of risk for contamination. While understanding higher risk sites is important, these data indicate the need for broad cleaning and disinfection, including surfaces that often receive less attention. In the present investigation, chairs and bulletin boards were sampled in patient rooms as it was noted that staff, patients, and visitors would move chairs by grasping the top surface of the chair back. Subsequently, MRSA and C. difficile were cultured from this surface with all positive chair backs specifically located in unexposed patient rooms. In unexposed and exposed patient rooms, bulletin boards were negative for MRSA but positive for C. difficile. Upon further investigation it was determined that in rooms with a patient under isolation precautions, tourniquets used for phlebotomies were secured to the bulletin boards. As C. difficile has been cultured from the skin of asymptomatic patients  and from the skin of patients with CDI [37, 38], it is theorized that the tourniquets became contaminated with C. difficile which subsequently contaminated the bulletin board. Although results from the univariable analyses indicated that bulletin boards, compared to the end of the patient bed, were not significantly associated with C. difficile contamination, cork surfaces, compared to plastic and fabric surfaces, had significantly increased odds of being contaminated with C. difficile. In this investigation all bulletin boards in patient rooms were made of cork, a porous material with an irregular surface. Due to the surface characteristics of cork, which make this material difficult to clean and disinfect, and the likelihood that bulletin boards were rarely, if ever disinfected, it is possible that bulletin boards may have acted as a source of C. difficile dissemination in patient rooms. It is not clear why MRSA was not recovered from any of the bulletin boards in this investigation since phlebotomy tourniquets have also been documented as acting as a reservoir for MRSA .
Overall, 2.5% and 5.9% of surfaces in the ward environment were contaminated with MRSA or C. difficile, respectively. However, in the literature, the prevalence of MRSA and C. difficile contamination of the general hospital environment is extremely variable [4, 28, 40–44] and therefore difficult to compare results between studies. These differences in prevalence may be attributed to different study designs as well as the presence and number of MRSA and C. difficile patients during the study period.
In the general ward environment, surfaces covered in fabric, laminate, or plastic had the highest level of MRSA or C. difficile contamination; however there was no statistically significant association between type of material and contamination. As these materials can vary widely in their texture, they can pose a substantial problem with respect to cleaning and disinfection, and therefore act as potential sources of MRSA and C. difficile transmission and dissemination. Staphylococcus aureus is able to survive adverse environmental conditions and persist in the hospital environment  including surviving in hospital dust for nearly a year . Experiments conducted using swatches of fabric and plastic have demonstrated that staphylococci can survive days to months after drying on these types of materials which are commonly found in the hospital environment . In addition, C. difficile spores are highly resistant to environmental effects and many commonly used disinfectants [47, 48], which can result in their survival for months to years in the hospital environment, unless physically removed or exposed to an adequate disinfectant .
In the ward environment, countertops, heating oven handles, computer keyboards, and chairs had the highest prevalence of MRSA or C. difficile contamination; however, there was no statistically significant association between specific surfaces and contamination with either pathogen. This lack of statistical association is in contrast to an earlier study investigating contamination in the ward environment of three hospitals in which chairs, hand rails, isolation carts, and sofas had significantly greater odds for MRSA contamination compared to computer keyboards . However, in that particular study, the prevalence of MRSA contamination was considerably higher (11.8%) and the low prevalence of C. difficile contamination (2.4%) did not allow for statistical model construction. Nonetheless, results from the present investigation demonstrate that contaminated surfaces are common hand-touch sites that are frequently touched by staff and/or patients and visitors. Therefore, contamination may be attributed to lack of hand hygiene, hand hygiene practices that are ineffective at eliminating C. difficile spores, and/or inconsistent cleaning and disinfection protocols.
During visits 3–6, C. difficile was identified as the predominant pathogen contaminating the ward environment. Although MRSA patients were present in the medical and surgical wards for all six visits, C. difficile patients were only present in the wards for visits 4–6. For visit 4 (week 13), the prevalence of MRSA was relatively small despite an MRSA outbreak during weeks 8–13; however there was no significant association between the prevalence of MRSA contamination prior to, and following, the outbreak. As the MRSA outbreak occurred on a ward not involved in this investigation, the substantial decrease of MRSA in the ward environment may have been a result of overall increase in hand hygiene and restricting patient movement and visitors to prevent the outbreak spreading to other wards. Furthermore, an influenza outbreak, which also occurred in a ward not participating in this investigation, was declared during weeks 9–11 of the study period. Following this outbreak, the prevalence of C. difficile contamination in the ward environment of the medical and surgical wards fluctuated over the last three visits with a substantially higher prevalence observed on visit 4; however, there was no significant association between the prevalence of C. difficile contamination before and after the outbreak. This increase in C. difficile contamination in the environment during the latter part of this investigation may have been attributed to the presence of C. difficile patients in the study wards. However, research has demonstrated an association between the presence of the influenza virus and an increase in the incidence rate of CDI in hospitalised patients during the winter months [49, 50]. Possible factors contributing to this association include antimicrobial use [49, 50] and reductions in cleaning and disinfection of non-outbreak wards because of increased efforts directed towards outbreak wards. In the present investigation, the monthly CDI incidence rate increased from 0.73 to 0.83 cases/1,000 patient days following the influenza outbreak. It is possible that patients with C. difficile were not identified and isolated, or a focus on influenza outbreak management led to decreased infection control activities directed against C. difficile, subsequently resulting in an increase in C. difficile contamination of the general environment.
The predominance of spa types corresponding to CMRSA-2, a sequence type 5 (ST5) clone, also known as USA100, was not unexpected since it is the leading cause of HA-MRSA in Canada [1, 51]. The distribution of MRSA strains in patient rooms, general ward areas, and patients was similar, albeit with more apparent strain diversity among patients than in the environment. It is unclear whether this indicates that CMRSA-2 is more adapted for surviving in the environment, as strain-dependent environmental persistence has not been investigated.
In total, 16 different toxigenic C. difficile ribotypes were identified. Ribotype 027 was predominant in the patient population and was the second most prevalent ribotype identified contaminating the ward environment. This specific ribotype is responsible for various outbreaks of CDI with increased severity, high relapse rates, and significant mortality [52, 53]. Despite its association with outbreaks, this ribotype is also common in endemic disease and was the second most prevalent strain in a study of C. difficile isolates from Ontario diagnostic laboratories . This is further evidence that while this strain is of particular concern, ribotype 027 can be present in patients and the environment in the absence of a CDI outbreak. Yet, overall, C. difficile typing data indicate less of a relationship between patient and environmental strains than with MRSA. In particular, ribotype 078 accounted for 64% of isolates from patient rooms and 36% from the ward environment but was identified in only one patient. Increases in the incidence of CDI caused by this particular strain have been reported internationally , including in Canada where 078 increased from 0.5% of CDI isolates in 2004/2005 to 1.6% in 2008 . The reason for the high prevalence of 078 in the environment of this healthcare facility and the discordance between environmental and patient prevalence is not known. However, this particular ribotype is prevalent among C. difficile strains isolated from food animals in Canada [57–59] and was commonly identified in a study of Ontario household environments . The participating hospital serves a rural community, which may increase the likelihood for exposure to 078 in the community, with subsequent transmission into the hospital. While ribotype 078 is referred to as a hypervirulent strain, it is not likely as pathogenic or transmissible as ribotype 027, based on fewer reports of severe disease or outbreaks associated with 078. Therefore, it is plausible that environmental contamination could occur more readily than patient disease if ribotype 078 is more common in people in the community but less able to cause disease, in comparison to ribotype 027. Given the lack of surveillance data involving non-diarrheic individuals, it is difficult to substantiate these hypotheses and more information is required regarding the epidemiology of this potentially emerging strain and the potential role of non-CDI patients, visitors, and staff in the contamination of the hospital environment.
The prevalence of toxinotype variants (toxinotypes other than toxinotype 0) in patients was striking, with only 14% of isolates belonging to toxinotype 0. The high prevalence and diversity of toxinotype variants seen in our study hospital have not been reported previously in a patient population and is in contrast with an earlier multicentre study in the province where ribotype 001, a toxinotype 0 strain, was most common (25.5%) . Similarly, the high prevalence of patient strains possessing the binary toxin strain (81%) was remarkably high. This toxin is most commonly found in hypervirulent strains, although it is not clear whether it is an important virulence factor or simply just commonly present in strains that are more virulent.
This study has several limitations. For C. difficile, several ribotypes present in the hospital environment were not identified from patient specimens. This discordance may have been attributed to isolates not being collected or patients with C. difficile not being identified because of a lack of routine screening or the use of a diagnostic test with moderate sensitivity [61, 62]. In addition, not all surfaces were sampled each visit since some surfaces were cleaned just prior to our arrival for sampling. Lastly, the number of MRSA and C. difficile exposed rooms available for sampling was limited, which may have resulted in a lack of power to identify significant risk factors associated with surfaces being contaminated with MRSA or C. difficile.