Comprehensive, multisystem, mechanical decolonization of Vancomycin-Resistant Enterococcus and Carbapenem-Resistant Enterobacteriacease without the use of antibiotics

Among multidrug-resistant organisms (MDROs), Vancomycin-resistant Enterococcus (VRE), and Carbapenem-resistant Enterobacteriaceae (CRE) have become major nosocomial pathogens that are endemic worldwide. If VRE/CRE are present as colonizing organisms but do not act as pathogens, these organisms do not cause symptoms and do not require antibiotic use. However, once gastrointestinal colonization with VRE/CRE occurs, it can persist for long periods and serve as a reservoir for transmission to other patients. Therefore, a breakthrough strategy to control the spread of MDRO colonization is needed. We herein introduce decolonization method, which is a comprehensive, multisystem, consecutive mechanical MDRO decolonization protocol that does not utilize antibiotics. Our protocol included: (1).. Mechanical evacuation using a glycerin enema, (2).. Replacement of the normal gut flora using daily lactobacillus ingestion, (3).. Skin hygiene cleansing using chlorhexidine, and (4).. Environmental cleansing by changing the bed sheets and clothing every day. These steps were repeated consecutively until the patient was released from quarantine. We conducted VRE/CRE tests every week. Because our protocol was a comprehensive and multisystem decolonization protocol, the cooperation of patients and/or caregivers was essential, and family support was important for patient care. Patients were divided into VRE and CRE groups and were subdivided into success and failure groups according to decolonization status. Thirty-two patients with VRE or CRE colonization were enrolled, and our protocol was performed. A total of 20 patients (62.5%) were successfully decolonized after repeated protocols. Univariate analysis revealed that patients with younger age, higher body mass index (BMI), shorter period of MDRO isolation without trial, and higher functional status showed significantly enhanced success rates with our decolonization protocol. This study presents the decolonization effects of a comprehensive, multisystem, mechanical decolonization protocol for VRE and CRE. Most importantly, our decolonization protocol does not use antibiotics and is thus not harmful. These results suggest an active decolonization trial to be performed as early as possible in patients with VRE or CRE colonization. This simple, easy-to-apply protocol can be used as 1 of the basic treatment options for MDROs infection or colonization, regardless of whether it requires antibiotic treatment.

The environmental stress sensitivities of pathogenic Candida species, including Candida auris, and implications for their spread in the hospital setting

Candida auris is an emerging pathogenic yeast of significant clinical concern because of its frequent intrinsic resistance to fluconazole and often other antifungal drugs and the high mortality rates associated with systemic infections. Furthermore, C. auris has a propensity for persistence and transmission in health care environments. The reasons for this efficient transmission are not well understood, and therefore we tested whether enhanced resistance to environmental stresses might contribute to the ability of C. auris to spread in health care environments. We compared C. auris to other pathogenic Candida species with respect to their resistance to individual stresses and combinations of stresses. Stress resistance was examined using in vitro assays on laboratory media and also on hospital linen. In general, the 17 C. auris isolates examined displayed similar degrees of resistance to oxidative, nitrosative, cationic and cell wall stresses as clinical isolates of C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, C. krusei, C. guilliermondii, C. lusitaniae and C. kefyr. All of the C. auris isolates examined were more sensitive to low pH (pH 2, but not pH 4) compared to C. albicans, but were more resistant to high pH (pH 13). C. auris was also sensitive to low pH, when tested on contaminated hospital linen. Most C. auris isolates were relatively thermotolerant, displaying significant growth at 47°C. Furthermore, C. auris was relatively resistant to certain combinations of combinatorial stress (e.g., pH 13 plus 47°C). Significantly, C. auris was sensitive to the stress combinations imposed by hospital laundering protocol (pH > 12 plus heat shock at >80°C), suggesting that current laundering procedures are sufficient to limit the transmission of this fungal pathogen via hospital linen.

Contamination of hospital surfaces with respiratory pathogens in Bangladesh

With limited infection control practices in overcrowded Bangladeshi hospitals, surfaces may play an important role in the transmission of respiratory pathogens in hospital wards and pose a serious risk of infection for patients, health care workers, caregivers and visitors. In this study, we aimed to identify if surfaces near hospitalized patients with respiratory infections were contaminated with respiratory pathogens and to identify which surfaces were most commonly contaminated. Between September-November 2013, we collected respiratory (nasopharyngeal and oropharyngeal) swabs from patients hospitalized with respiratory illness in adult medicine and paediatric medicine wards at two public tertiary care hospitals in Bangladesh. We collected surface swabs from up to five surfaces near each case-patient including: the wall, bed rail, bed sheet, clinical file, and multipurpose towel used for care giving purposes. We tested swabs using real-time multiplex PCR for 19 viral and 12 bacterial pathogens. Case-patients with at least one pathogen detected had corresponding surface swabs tested for those same pathogens. Of 104 patients tested, 79 had a laboratory-confirmed respiratory pathogen. Of the 287 swabs collected from surfaces near these patients, 133 (46%) had evidence of contamination with at least one pathogen. The most commonly contaminated surfaces were the bed sheet and the towel. Sixty-two percent of patients with a laboratory-confirmed respiratory pathgen (49/79) had detectable viral or bacterial nucleic acid on at least one surface. Klebsiella pneumoniae was the most frequently detected pathogen on both respiratory swabs (32%, 33/104) and on surfaces near patients positive for this organism (97%, 32/33). Surfaces near patients hospitalized with respiratory infections were frequently contaminated by pathogens, with Klebsiella pneumoniae being most common, highlighting the potential for transmission of respiratory pathogens via surfaces. Efforts to introduce routine cleaning in wards may be a feasible strategy to improve infection control, given that severe space constraints prohibit cohorting patients with respiratory illness.

How clean is "hygienically clean": Quantitative microbial levels from samples of clean health care textiles across the United States

BACKGROUND

In the United States, the laundry industry has not reliably measured microbial levels on hygienically clean textiles. The aim of this study was to quantitatively measure the microbial levels found on a sample of hygienically clean textiles.

METHODS

Forty-eight health care textile samples were collected from hygienically clean linen scheduled to be used on 3 different patient care units. Samples were taken at 2 separate points in time representing laundry facility processing practices and hospital linen management practices. United States Pharmacopeia 61 testing was completed using a pour plate culturing method, producing a total aerobic microbial count and a total yeast and mold count.

RESULTS

Of the samples, only 27% had a total aerobic microbial count below the expected 100 colony-forming unit level (range, 9-40,000) versus 81% (range, 9-1,000) for total yeast and mold count. Median microbial counts for the 2 separate time points across the 3 different patient care units were also higher than expected.

CONCLUSIONS

As far as we know, this study is a first step by the laundry industry to understand what quantitative microbial levels are currently found on hygienically clean health care textiles. These types of data can assist the industry in establishing appropriate outcome targets for process improvement initiatives.

Exhaust Air Dust Monitoring is Superior to Soiled Bedding Sentinels for the Detection of Pasteurella pneumotropica in Individually Ventilated Cage Systems

Reliable detection of unwanted organisms is essential for meaningful health monitoring in experimental animal facilities. Currently, most rodents are housed in IVC systems, which prevent the aerogenic transmission of pathogens between cages. Typically soiled-bedding sentinels (SBS) exposed to soiled bedding collected from a population of animals within an IVC rack are tested as representatives, but infectious agents often go undetected due to inefficient transmission. Pasteurellaceae are among the most prevalent bacterial pathogens isolated from experimental mice, and the failure of SBS to detect these bacteria is well established. In this study, we investigated whether analysis of exhaust air dust (EAD) samples by using a sensitive and specific real-time PCR assay is superior to conventional SBS monitoring for the detection of Pasteurella pneumotropica (Pp) infections. In a rack with a known prevalence of Pp-positive mice, weekly EAD sampling was compared with the classic SBS method over 3 mo. In 6 rounds of testing, with a prevalence of 5 infected mice in each of 7 cages in a rack of 63 cages, EAD PCR detected Pp at every weekly time point; SBS failed to detect Pp in all cases. The minimal prevalence of Pp-infected mice required to obtain a reliable positive result by EAD PCR testing was determined to be 1 in 63 cages. Reliable detection of Pp was achieved after only 1 wk of exposure. Analysis of EAD samples by real-time PCR assay provides a sensitive, simple, and reliable approach for Pp identification in laboratory mice.

[Increase in Bacillus spp.-positive Blood Culture Specimens Linked to Inadequate Linen Management]

Bacillus cereus is a gram-positive rod-type bacterium that forms endospores and is distributed throughout various environments. It rarely causes disease in humans except for cases of food poisoning. However, infection with B. cereus in newborns and immunocompromised individuals can cause severe sepsis. Inappropriate catheter insertion and environmental contamination, including that of linen, are thought to be routes of transmission. Pseudo-outbreaks of B. cereus caused by poor hospital linen management have been reported and are important issues in hospitals. The number of Bacillus spp.-positive blood culture specimens increased in "A" ward of our hospital. Consequently, the hospital's infection control team was asked to determine the cause of the increase. We performed environmental research in the "A" ward and the entire hospital. In addition, we investigated the current status of B. cereus derection in five core hospitals in the North Tohoku region. In our hospital, B. cereus was detected in towels before use. When the timeline of contamination was investigated, we found that the towels had already been contaminated at the time they were delivered to our hospital. The linen washing contractor was unconcerned with laundry disinfection. As a result of our findings, disposable towels were introduced. This resulted in a decrease in Bacillus spp.-positive blood culture specimens. Among the five core hospitals in the North Tohoku region, the hospitals outsourcing laundry to contractors without bacteriological monitoring had a significantly higher rate of B. cereus-positive blood cultures than those of three other hospitals with infection control policies for towel management. The increase in Bacillus spp.-positive blood culture specimens in our hospital was a result of towel contamination. Based on these findings, we suggest that proper linen management(including that of towels) is crucial for infection control as well as the quality control of bacteriological tests.

The bedding of laboratory animals as a source of airborne contaminants

In work environments with laboratory animals, the bedding of animals binds the excreta as well as other compounds originating from the animals and their environment. These may be generated into the ambient air when the personnel handle bedding in different procedures. This study compares the dustiness of different types of six clean and four soiled beddings from rat or mouse cages. The dust generation of clean bedding varied from <1 to 25 mg/m3. When used in the cages of rats or mice for 4 days, the dust concentration of the beddings decreased, increased or stayed the same, depending on the type of bedding and animal species. A decrease in dustiness was, however, more common. The levels in the soiled beddings varied from <1 to 8.6 mg/m3. In the case of the aspen chip bedding, the contents of bedding used in mouse, rat or rabbit cages were analysed for mesophilic bacteria and fungi, mycobacteria and endotoxins. All of these contaminants were variably found in the bedding samples, the maximal concentrations for bacteria were >6 500 000 colony-forming units (cfu)/g, for fungi 212 000 cfu/g, and for endotoxins 6500 ng/g (81 000 EU/g). The results showed that the bedding of laboratory animals may contain biologically effective compounds, and that these may be distributed into the ambient air depending on the characteristics of the bedding material. The dustiness of different bedding types is an important factor affecting the amount and quality of the occupational exposure of the personnel to airborne contaminants.

[Evaluation of microbial contamination of linens in industrial laundry processes]

Laundering linens and protecting them from microbiological recontamination are critical issues for the hotel and food industries and especially for hospitals. This study was performed to evaluate a sample of industrial laundries in Sardinia (Italy), to assess their compliance with national hygienic and sanitary regulations, along the complete laundering process. Study results indicate that industrial laundering processes are effective and that better awareness of staff who handle laundered textiles is required to reduce the risk of recontamination.

Addition of Bacillus sp. inoculums in bedding for swine on a pilot scale: effect on microbial population and bedding temperature

Thermal and microbiological characteristics of beddings for swine were compared according to their depth and of addition of inoculums. Bedding was added to boxes at 0.25 (25D) and 0.50 m (50D), with three treatments: control (no inoculums); T1, with 250 g of Bacillus cereus var. toyoii at 8.4 × 10(7) CFU; and T2, with 250 g of a pool of B. subtilis, Bacillus licheniformis and Bacillus polymyxa at 8.4 × 10(7) CFU (250 g for 25D and 500 g for 50D). Mean temperatures were 28.5 ± 3.9 at the surface and 35.2 ± 8.9 inside the beddings. The most probable number (MPN) of thermophilic bacteria was higher for T1 and T2 than for the control (P<0.05). The MPN of thermophilic bacteria and fungi was greater for D50 than for D25 (P<0.05). The use of 25D without inoculums is recommended due to the reduction of thermophilic microbiota.

Hospital textiles, are they a possible vehicle for healthcare-associated infections?

Textiles are a common material in healthcare facilities; therefore it is important that they do not pose as a vehicle for the transfer of pathogens to patients or hospital workers. During the course of use hospital textiles become contaminated and laundering is necessary. Laundering of healthcare textiles is most commonly adequate, but in some instances, due to inappropriate disinfection or subsequent recontamination, the textiles may become a contaminated inanimate surface with the possibility to transfer pathogens. In this review we searched the published literature in order to answer four review questions: (1) Are there any reports on the survival of microorganisms on hospital textiles after laundering? (2) Are there any reports that indicate the presence of microorganisms on hospital textiles during use? (3) Are there any reports that microorganisms on textiles are a possible source infection of patients? (4) Are there any reports that microorganisms on textiles are a possible source infection for healthcare workers?

Prevalence of murine Helicobacter spp. Infection is reduced by restocking research colonies with Helicobacter-free mice

Most academic research colonies of mice are endemically infected with enterohepatic Helicobacter spp. (EHS). We evaluated EHS prevalence in surveillance mice before and after a 10-y period of requiring that imported mice be free of EHS by embryo transfer rederivation or purchase from approved vendors. In 2009, composite fecal samples from CD1 surveillance mice representing colony health in 57 rooms located in 6 facilities were evaluated for EHS infection by using PCR assays. Fecal samples were screened with primers designed to detect all known EHS, and positive samples were further assayed by using primers specific for H. hepaticus, H. bilis, H. rodentium, and H. typhlonicus. Most EHS were detected in surveillance mice within the first month of dirty bedding exposure, with prevalence ranging from 0% to 64% as monoinfections or, more commonly, infections with multiple EHS. Compared with 1999 prevalence data, EHS remained endemic in colonies importing the lowest number of EHS-free mice. EHS were absent or the prevalence was greatly reduced in colonies receiving the highest percentage of EHS-free mice. This study demonstrates that the management decision to require exclusive importation of EHS-free mice reduced EHS prevalence on an institutional scale without intensive labor and expense associated with other techniques or interference with research objectives.

Nosocomial diarrhoea in relation to sanitation state: a study in Tikrit, Iraq

A cross-sectional hospital-based study of 259 children aged < 5 years was carried out in Tikrit, Iraq, to identify the prevalence of nosocomial diarrhoea and sources of contamination in the ward environment. Nosocomial diarrhoea was diagnosed in 84 children (32.4%). Children with diarrhoea were more likely than unaffected children to be bottle-fed, given unboiled water, to have unclean food containers and contaminated bed sheets. Three out of 5 brands of formula milk (unopened cans) were contaminated. Three-quarters of medical staff and employees had contaminated hands. Enterobacter spp., Pseudomonas aeruginosa and Citrobacter spp. were the most commonly identified microorganisms. A greater emphasis on personal hygiene, improved care practices and promotion of breastfeeding is recommended.

Endotoxin, coliform, and dust levels in various types of rodent bedding

Endotoxins in grain dust, household dust, and animal bedding may induce respiratory symptoms in rodents and humans. We assayed the endotoxin, coliform, and dust levels in 20 types of rodent bedding. Endotoxin concentrations were measured by using a commercial test kit, coliform counts were determined by using conventional microbiologic procedures, and dust content was evaluated by using a rotating-tapping shaker. Paper bedding types contained significantly less endotoxin than did other bedding types; the highest levels of endotoxin were detected in hardwood and corncob beddings. The range of endotoxin content for each bedding type was: corncob bedding, 1913 to 4504 endotoxin units per gram (EU/g); hardwood bedding, 3121 to 5401 EU/g; corncob-paper mixed bedding, 1586 to 2416 EU/g; and paper bedding, less than 5 to 105 EU/g. Coliform counts varied from less than 10 to 7591 cfu/g in corncob beddings, 90 to 4010 cfu/g in corncob-paper mixed beddings, less than 10 to 137 cfu/g in hardwood beddings, and less than 10 cfu/g in paper beddings. Average dust content was less than 0.15% in all commercial bedding types. We conclude that paper bedding is the optimal bedding type for conducting LPS inhalation studies and that rodent bedding containing high levels of endotoxin may alter the results of respiratory and immunologic studies in rodents.

[Microbiological assesssment of efficiency chemothermal disinfection of blood contaminated hospital textiles]

Thermal disinfection should be applied to laundering procedures of hospital textiles contaminated with blood. Currently, there is an increasing number of hospital textiles composed of cotton-polyester blends that cannot endure high temperatures of thermal disinfection. Besides, decreasing the temperature of chemothermal disinfection enhances the possibility of micro-organisms to survive the laundering procedure. The aim of this study was to prepare a new method for the microbiological evaluation of disinfecting laundering procedures for hospital textiles contaminated with blood. The bactericidal activity of chemical disinfectants for chemothermal disinfection was determined by simulating a laundering procedure for hospital textiles in the laboratory according to procedure of National Institute of Hygiene - DF/05/03. Bioindicators cotton carriers inoculated with Enterococcus faecium were used for determinating the antibacterial effects for hospital textiles contaminated with blood. High concentrations of bovine albumin and/or sheep erythrocytes were used as substrate for simulating human blood. The results showed that the bactericidal activity of chemical disinfectants for chemothermal disinfection hospital textiles in the event of massive organic contamination--heavily soiled with blood, shall be evaluated using carrier test in following conditions: test organism- Enterococcus faecium, interfering substances--6 g/l bovine albumin solution added to preparation.

Centers for Disease Control and Prevention (CDC). Methicillin-resistant Staphylococcus aureus among players on a high school football team--New York City, 2007

On September 12, 2007, the New York City Department of Health and Mental Hygiene (DOHMH) was notified of three players on a Brooklyn high school football team with culture-confirmed methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs). During August 19--24, the team had attended a preseason football training camp, where all 59 players on the team lived together in the school gymnasium. An investigation by DOHMH revealed four culture-confirmed and two suspected cases of MRSA among 51 players interviewed (11.8% attack rate). Of the six cases, three involved abscesses that required incision and drainage. The risk for MRSA infection was higher among those who shared towels during the training camp than among those who did not (relative risk [RR] = 8.2). In addition, the six players with MRSA infections had a mean body mass index (BMI) that was significantly higher than the mean for those who were not infected. Multivariable logistic modeling determined that sharing towels during camp (adjusted odds ratio [AOR] = 15.7) and higher BMI (AOR = 1.4) were associated independently with MRSA infection. Similar outbreaks have been reported among football teams in which inadequate hygiene, combined with skin injuries and living in close quarters, contributed to the spread of MRSA infection. Such outbreaks might be prevented by better educating players and coaches regarding SSTIs and by better promoting proper player hygiene, particularly during training camps.

Minimizing the Level of Butyric Acid Bacteria Spores in Farm Tank Milk

A year-long survey of 24 dairy farms was conducted to determine the effects of farm management on the concentrations of butyric acid bacteria (BAB) spores in farm tank milk (FTM). The results were used to validate a control strategy derived from model simulations. The BAB spore concentrations were measured in samples of FTM, feces, bedding material, mixed corn and grass silage fed to cows in the barn, and soil. In addition, a questionnaire was used to gather farm management information such as bedding material used and teat cleaning method applied. The average BAB spore concentration in FTM was 2.7 log10 spores/L, and 33% of the FTM samples exceeded a concentration of 3 log10 spores/L. Control of the average spore concentration in mixed silage fed was the only aspect of farm management that was significantly related to the concentration of BAB spores in FTM. Farms that fed mixed silage with the lowest average BAB spore concentrations (3.4 log10 spores/g) produced FTM with the lowest average concentration (2.1 log10 spores/L). The efficiency of farm management in controlling the BAB spore concentration in FTM depended to a large extent on the ability of farmers to prevent incidents with elevated BAB spore concentrations in mixed silage (>5 log10 spores/g) and not on the average BAB spore concentration in mixed silage across the year. The survey showed that farmers should aim for a concentration in mixed silage of less than 3 log10 spores/g and should prevent the concentration from exceeding 5 log10 spores/g to ensure a concentration in FTM of less than 3 log10 spores/L. These results correspond with the previously reported model simulations.

Minimizing the Level of Bacillus cereus Spores in Farm Tank Milk

In a year-long survey on 24 Dutch farms, Bacillus cereus spore concentrations were measured in farm tank milk (FTM), feces, bedding material, mixed grass and corn silage, and soil from the pasture. The aim of this study was to determine, in practice, factors affecting the concentration of B. cereus spores in FTM throughout the year. In addition, the results of the survey were used in combination with a previously published modeling study to determine requirements for a strategy to control B. cereus spore concentrations in FTM below the MSL of 3 log10 spores/L. The B. cereus spore concentration in FTM was 1.2 +/- 0.05 log10 spores/L and in none of samples was the concentration above the MSL. The spore concentration in soil (4.9 +/- 0.04 log10 spores/g) was more than 100-fold higher than the concentration in feces (2.2 +/- 0.05 log10 spores/g), bedding material (2.8 +/- 0.07 log10 spores/g), and mixed silage (2.4 +/- 0.07 log10 spores/g). The spore concentration in FTM increased between July and September compared with the rest of the year (0.5 +/- 0.02 log10 spores/L difference). In this period, comparable increases of the concentrations in feces (0.4 +/- 0.03 log10 spores/g), bedding material (0.5 +/- 0.05 log10 spores/g), and mixed silage (0.4 +/- 0.05 log10 spores/g) were found. The increased B. cereus spore concentration in FTM was not related to the grazing of cows. Significant correlations were found between the spore concentrations in FTM and feces (r = 0.51) and in feces and mixed silage (r = 0.43) when the cows grazed. The increased concentrations during summer could be explained by an increased growth of B. cereus due to the higher temperatures. We concluded that year-round B. cereus spores were predominantly transmitted from feeds, via feces, to FTM. Farmers should take measures that minimize the transmission of spores via this route by ensuring low initial contamination levels in the feeds (<3 log10 spores/g) and by preventing growth of B. cereus in the farm environment. In addition, because of the extremely high B. cereus spore concentrations in soil, the contamination of teats with soil needs to be prevented.

Proliferation of mycobacteria in a piggery environment revealed by mycobacterium-specific real-time quantitative PCR and 16S rRNA sandwich hybridization

Pig mycobacteriosis is the most common animal mycobacterial disease in Finland with a long-term average prevalence of 0.34% and temporary peaks as high as 0.85%. In the current study Mycobacterium-specific real-time qPCR and 16S rRNA sandwich hybridization were utilized for culture-independent detection and measurement of potentially infectious mycobacteria in selected piggeries. Participating herds (n=5) were selected according to prevalence of tuberculous lesions (>4%) in slaughtered carcasses. When DNA extracted from piggery bedding materials was analyzed by Mycobacterium-targeted qPCR using the SYBR green I dye for detection of amplification products, 10(5) to 10(7) cell equivalents of mycobacterial DNA were detected in unused bedding materials and 10(8) to 10(10)g(-1) dry weight in used bedding materials. When Mycobacterium-specific hybridization probes were used for detection of amplification products, 10(5) to 10(7) cell equivalents of mycobacterial DNA g(-1) dry weight were detected in unused bedding materials in four out of the five piggeries studied and up to 10(8) cell equivalents in used bedding material. The results were confirmed by the Mycobacterium-specific 16S rRNA sandwich hybridization assay. The present results show, that mycobacteria occur in organic materials commonly used on pig farms, and may proliferate in bedding materials during use. We also show that DNA- and RNA-based methods may be utilized for detection of environmental reservoirs of mycobacteria causing porcine and human infection.

Antimicrobial disinfection effect of a laundering procedure for hospital textiles against various indicator bacteria and fungi using different substrates for simulating human excrements

Recent studies confirm the increase of nosocomial infections and microbial resistance. One of the possible causes is infected textiles due to inappropriate laundering procedures. Most Slovenian laundries use thermal laundering procedures with high energy and water consumption to disinfect hospital textiles. In addition to this fact, there is an increasing number of hospital textiles composed of cotton/polyester blends that cannot endure high temperatures of thermal disinfection. On the other hand, decreasing the temperature of laundering procedures enhances the possibility of pathogenic microorganisms to survive the laundering procedure. In our research, we determined the antimicrobic laundering effect by simulating a common laundering procedure for hospital textiles in the laboratory washing machine at different temperatures by the use of bioindicators. Enterococcus faecium, Staphylococcus aureus, Mycobacterium terrae, Enterobacter aerogenes, and Pseudomonas aeruginosa were used for determining the antibacterial laundering effect. Candida albicans was used for determining the antifungal laundering effect. Swine blood, artificial sweat, and swine fat were used as substrates for simulating human excrements and were inoculated together with the chosen microorganisms onto cotton pieces to simulate real laundering conditions. It was found that E. faecium, S. aureus, E. aerogenes, and P. aeruginosa survived at 60 degrees C, but no microorganisms were found at 75 degrees C.

Methicillin-resistant Staphylococcus aureus survival on hospital fomites

We examined the duration of survival of 2 strains of methicillin-resistant Staphylococcus aureus (MRSA) on 3 types of hospital fomites. MRSA survived for 11 days on a plastic patient chart, more than 12 days on a laminated tabletop, and 9 days on a cloth curtain. Irregular surfaces may help harbor organisms in the environment. In addition to contact precautions, MRSA containment during an outbreak should include concurrent environmental decontamination.

Fecal Shedding of Klebsiella pneumoniae by Dairy Cows

Klebsiella pneumoniae is a common cause of clinical mastitis in dairy cattle. Wood products are considered to be the main source of Klebsiella on dairy farms. Environmental hygiene and use of inorganic bedding materials such as sand are recommended to control Klebsiella mastitis. However, Klebsiella mastitis still occurs on well-managed dairy farms that use sand as bedding material. In a 5-mo study in a New York State dairy herd performed during the summer of 2005, all of 9 samples of unused sand bedding tested negative for Klebsiella, whereas 14 of 18 samples of used sand bedding contained Klebsiella at a median level of 10(4.6) cfu/g. We hypothesized that fecal shedding of Klebsiella by dairy cows contributes to the presence of Klebsiella in the environment. Using a cheap and simple method based on ampicillin-containing MacConkey agar for screening, and biochemical tests for confirmation of species identity, 595 fecal samples from healthy dairy cattle were screened for presence of Klebsiella. In a longitudinal study of 100 cows followed over 5 mo, more than 80% of fecal samples tested positive for K. pneumoniae. The average prevalence of K. pneumoniae-positive fecal samples was also above 80% in a cross-sectional study of 100 cows from 10 herds across New York and Massachusetts. Fecal shedding of K. pneumoniae by a large proportion of dairy cows may explain why Klebsiella mastitis occurs in herds that use inorganic bedding material or other bedding material that is free from Klebsiella upon introduction into the barn.

Implementing hygiene monitoring systems in hospital laundries in order to reduce microbial contamination of hospital textiles

As textiles sent to hospital laundries contain many types of pathogenic organisms, it is important that laundering not only has an appropriate cleaning effect but also has a satisfactory disinfecting effect. Critical to this process is the maintenance of an appropriate hygiene level in the clean area of laundries in order to prevent recontamination of textiles from manual handling when ironing, folding, packing etc. The aims of this study were to evaluate the hygienic state of a hospital laundry, to introduce continuous sanitary measures, and to introduce a continuous hygiene monitoring system with an infection control programme. Two systems for evaluating hospital laundry hygiene were combined: HACCP principles (hazard analysis and critical control points) and RAL-GZ 992 standards (quality assurance standard for textile care of hospital laundry). Evaluation of the hygienic state of the hospital laundry was carried out by evaluating the number and types of micro-organisms present at the critical control points throughout the whole laundering process, using RODAC agar plates for surface sampling and the pour plate method for investigating water samples. The initial examination showed that the sanitary condition of the laundry did not reach the required hygiene level. Therefore, fundamental sanitation measures were instituted and the examination was repeated. Results were then satisfactory. The most important critical control point was the chemothermal laundering efficiency of the laundering process. To prevent micro-organisms spreading into the entire clean working area, it is important that, in addition to regular sanitary measures such as cleaning/disinfecting all working areas, technical equipment and storage shelves etc., regular education sessions for laundry employees on proper hand hygiene is undertaken and effective separation of the clean and dirty working areas is achieved.

Growth and survival of bacteria implicated in sudden infant death syndrome on cot mattress materials

AIMS

To compare growth and survival of selected bacteria implicated in sudden infant death syndrome (SIDS) on cot mattress polyurethane (PU) inner-foams and on different types of cot mattress cover materials.

METHODS AND RESULTS

Escherichia coli, Staphylococcus aureus or Streptococcus pyogenes were inoculated onto swatches of new-unused cot mattress PU inner-foam and onto three types of cot mattress covers (polyvinyl chloride, cotton and polyester). The influence of inoculation cell density, relative humidity (RH) and temperature of incubation on survival was assessed by recovery of cells in 0.85% NaCl, with viable cell enumeration by plate counting on selective and differential media. Utilization of carbon and nitrogen sources within cot mattress PU was assessed by following growth on aqueous leachate from PU, and by colorimetric determination of aromatic amines. Good survival capability (>206 d) was shown by all three test species on PU inner-foam and on polyester mattress cover at high RH (75%), but only by Staph. aureus on PU at low RH (25%). Aqueous soluble material from PU foam supports bacterial growth; removal of aromatic amines from aqueous leachate from PU accompanies growth of Staph. aureus.

CONCLUSIONS

Staphylococcus aureus has good survival capability on cot mattress PU foam, even at low RH. Soluble material within PU can serve as carbon and nitrogen sources for bacterial growth.

SIGNIFICANCE AND IMPACT OF THE STUDY

Prolonged survival of Staph. aureus on PU at low RH could explain, in the context of the common bacterial toxins hypothesis, an increased risk of SIDS associated with used infant mattresses.

Growth performance and health of dairy calves bedded with different types of materials

Granite fines, sand, rice hulls, long wheat straw, and wood shavings were compared as bedding for 60 female dairy calves. Growth, health, stress indices, and behavior of newly born calves, along with physical characteristics and bacterial counts of bedding, were evaluated for 42 d during August to October, 2002. Overall average daily gain and dry matter intake of calves did not differ due to bedding type, although during wk 2 calves housed on rice hulls had the greatest dry matter intake and those housed on wood shavings had the lowest. During wk 2, calves housed on granite fines and sand were treated more often for scours, and calves housed on long wheat straw received the fewest antibiotic treatments (week by bedding material interaction). Granite fines formed a harder surface than other bedding, and calves housed on granite fines scored the dirtiest. When bedding materials were evaluated, sand was scored to be the dirtiest, while pens bedded with rice hulls, long wheat straw, and wood shavings scored cleaner. Long wheat straw had the warmest surface temperature, and rice hulls and wood shavings were warmer than granite fines and sand. Serum cortisol, alpha(1)-acid glycoprotein, immunoglobulin G concentrations, and the neutrophil:lymphocyte ratio were not affected by bedding type. On d 0, coliform counts were greatest in rice hulls. After use, coliform counts were greatest in long wheat straw (week by bedding material interaction). On d 42, the concentration of ammonia at 10 cm above the bedding was lowest for long wheat straw. Growth performance of calves bedded for 42 d with 5 bedding types did not differ; however, the number of antibiotic treatments given for scours was greatest on granite fines and sand; coliform counts in the bedding were highest in rice hulls before use and in long wheat straw after 42 d of use.

Minimising cross-infection risks associated with beds and mattresses

The spread of infection can be associated with inanimate objects in the environment, referred to as fomites. These include beds, mattresses, curtains, bedpans and sphygmomanometers, all of which may be contaminated with micro-organisms (Wilson, 2001).

Cot mattresses as reservoirs of potentially harmful bacteria and the sudden infant death syndrome

Cot mattress materials were investigated as potential reservoirs of bacteria in relation to the sudden infant death syndrome (SIDS). The sleeping position of the infant significantly influenced bacterial population density of cot mattress polyurethane foams (p<0.0000001) and their covers (p<0.004). Staphylococcus aureus was isolated at significantly higher frequency (p<0.03) from the infant's head region of cot mattress materials. Significantly higher bacterial population densities (p<0.001) were associated with polyurethane foams from non-integral mattresses (exposed polyurethane foam), when compared to those from mattresses completely covered by polyvinyl chloride (integral type mattress). The frequency of isolation of S. aureus from polyurethane foams from non-integral mattresses was also significantly higher (p=0.03) than from foams from the integral type. The following factors were significantly associated with increased frequency of isolation of S. aureus: from the polyurethane foam, previous use of non-integral mattresses by another child (p=0.03 for all sample sites, p=0.01 for torso region); from the covers, sleeping in the prone position (p=0.003 head region, p=0.001 torso region). Prone sleeping was also significantly associated with increased bacterial population levels (p=0.01) and increased frequency of isolation of Escherichia coli (p=0.02) from the torso region of cot mattress covers. These findings could explain some recently identified risk factors for SIDS associated with type and previous use of cot mattresses. Clostridium perfringens was isolated at very low frequency and Streptococcus pyogenes was not isolated from any cot mattress materials tested.

Microbial exposure of rural school children, as assessed by levels of N-acetyl-muramic acid in mattress dust, and its association with respiratory health

BACKGROUND

Endotoxin exposure has been shown to be associated with a decreased prevalence of atopic sensitization and symptoms. Yet endotoxin represents only a part of the indoor microbial exposure. Muramic acid, a constituent of peptidoglycan, is present in gram-negative and gram-positive bacteria in the environment and may therefore serve as an additional marker of microbial exposure.

OBJECTIVE

To study the factors determining the level of indoor exposure to muramic acid/peptidoglycan, as well as its potential association with respiratory health.

METHODS

In 553 farm and nonfarm school children from Austria, Switzerland, and Germany, mattress dust muramic acid concentrations were determined, and health was assessed by using IgE measurements and questionnaire information.

RESULTS

The muramic acid concentration was found to be significantly higher in dust from farm children's mattresses than in dust from nonfarm children's mattresses (157 vs 131 ng/mg). Children with higher mattress dust muramic acid concentrations had a significantly lower prevalence of wheezing (odds ratio of highest vs lowest tertile of muramic acid concentration, 0.3; 95% CI, 0.1-0.9), regardless of farming status and endotoxin exposure. The association for asthma was similar, and no association was found with atopic sensitization.

CONCLUSION

Next to endotoxin, muramic acid provides us with an independent marker of microbial exposure. Unlike endotoxin, muramic acid was inversely associated with wheezing rather than with atopic sensitization.

Pressure sore prevention pads as an infective source in orthopaedic theatres

Current theatre practice and protocol involves the use of pressure sore prevention pads in the positioning and support of all patients undergoing orthopaedic surgery. Microbiological swabs were taken from those pads placed adjacent to the operative field immediately before implant surgery. Eleven out of the 13 pads sampled yielded bacterial growth capable of causing deep-seated infection. The transfer of these pads between the designated orthopaedic theatres and the rest of the theatre complex was also noted. We recommend that the use of these pads should be closely reviewed. They should either be used with stricter guidelines for decontamination between use or disposable 'clean' alternatives sought.

Experimental murine cryptococcal infection results in contamination of bedding with Cryptococcus neoformans

Cryptococcus neoformans is a fungal pathogen that survives in diverse environments. To determine whether cages of mice infected with C. neoformans posed an infection risk to animal caregivers, we investigated whether the fungus could be isolated from the bedding or stool of mice infected by intratracheal (i.t.), intravenous (i.v.), or intraperitoneal (i.p.) routes. The bedding of mice infected i.t. was contaminated with C. neoformans. In contrast, no contamination of bedding with C. neoformans was detected in cages of mice infected i.v. or i.p. C. neoformans was not isolated from murine feces. The C. neoformans strain recovered from bedding material was indistinguishable from the infecting strain by biochemical and molecular techniques. This result suggests that precautions may be warranted when disposing bedding from cages that housed mice with pulmonary C. neoformans infection.

Arsenic methylation by micro-organisms isolated from sheepskin bedding materials

Sudden infant death syndrome (SIDS) has been associated with the volatilization of arsenic, antimony or phosphorus compounds from infants' bedding material by micro-organisms, the so-called 'toxic gas hypothesis'. The volatilization of arsenic by aerobic micro-organisms isolated from new sheepskin bedding material, as well as on material used by a healthy infant and by an infant who perished of SIDS, was examined. Three fungi were isolated from a piece of sheepskin bedding material on which an infant perished of SIDS, which methylated arsenic to form trimethylarsenic(V) species, precursors to volatile trimethylarsine. These three fungi were identified as Scopulariopsis koningii, Fomitopsis pinicola and Penicillium gladioli by their 26S-ribosomal RNA polymerase chain reaction products. These fungi were not previously known to methylate arsenic. The volatilization of arsenic by these three fungi was then examined. Only P. gladioli volatilized arsenic and only under conditions such that the production of sufficient trimethylarsine to be acutely toxic to an infant is unlikely. S. brevicaulis grew on the sheepskin bedding material and evolved a trace amount of trimethylarsine. Known human pathogens such as Mycobacterium neoaurum and Acinetobacter junii were isolated from used bedding.

Microbiological threats to health in the home

OBJECTIVE

To explore a range of pathogenic microorganisms and their toxins that can cause disease in the home environment through a review of the literature.

DESIGN

Review of the literature.

Bacterial strike-through of re-usable surgical drapes: the effect of different wetting agents

Wound contamination and the resultant postoperative infection is a major problem in all forms of surgery. Air contamination, gloves, surgical instruments and drapes have all been investigated as sources of wound contamination. We investigated the effect of different wetting agents on strike-through rate of bacteria through re-usable polyester/cotton surgical drapes using a newly described method. Within 30 min bacterial strike-through of dry surgical drapes occurs. Wetting drapes with blood or normal saline enhances the strike-through rate of bacteria. Wetting drapes with iodine or chlorhexidine diminishes, but does not stop, bacterial strike-through. The use of re-usable polyester/cotton drapes is a potential source of wound contamination especially when wetted with blood or normal saline.

Microbial cell wall product contamination of bedding may induce pulmonary inflammation in rats

To test the hypothesis that airborne microbial cell wall components could induce an inflammatory response in the lungs, measurements were made of the amounts of bacterial endotoxin and (1-->3)-beta-D-glucan in laboratory animal bedding materials. Groups of rats were exposed by inhalation to airborne endotoxin, (1-->3)-beta-D-glucan or a combination of the two for 5 weeks. The results demonstrated that measurable amounts of endotoxin and (1-->3)-beta-D-glucan could be detected in the different bedding materials. In contrast to animals at delivery, those kept on bedding for 5 weeks showed moderate inflammatory reactions in the lung. These were most pronounced among animals exposed to endotoxin and (1-->3)-beta-D-glucan. The results suggest that further studies need to be undertaken to elucidate the role of microbial cell wall products in the development of inflammatory lung responses among research animals.

Survival of some medically important fungi on hospital fabrics and plastics

Tests of the survival of Candida spp., Aspergillus spp., a Fusarium sp., a Mucor sp., and a Paecilomyces sp. on hospital fabrics and plastics indicated that viability was variable, with most fungi surviving at least 1 day but many living for weeks. These findings reinforce the need for appropriate disinfection and conscientious contact control precautions.

A survey of gram-negative bacteria survival on hospital fabrics and plastics

One critical factor for the transmission of microorganisms from person to person or from the environment to a person (patient or health care worker) is the ability of the microbe to survive on an environmental surface. The purpose of this study was to determine the length of survival of various gram-negative bacteria on fabrics and plastics commonly used in hospitals. Seven materials were tested: smooth cotton (clothing), cotton terry (towels), 60% cotton-40% polyester blend (scrub suits and lab coats), polyester (drapes), 75% nylon-25% spandex (pressure garments), polyvinyl (splash aprons), and polyurethane (keyboard covers). The following bacteria were tested: Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Proteus mirabilis, Acinetobacter species, and Enterobacter species. Swatches of the materials were inoculated with defined amounts of bacteria and assayed at regular intervals. Survival was dependent on the bacterium, its inoculum size, and the material tested. At 102 microorganisms per swatch, bacteria survived from less than 1 hour to 8 days. At 10(4) to 10(5) bacteria per swatch, survival ranged from 2 hours to more than 60 days. These findings emphasize the need for careful disinfection and conscientious contact control procedures in areas that serve immunosuppressed individuals, such as patients with burn injuries.

Bacterial contamination of curtains in clinical areas

A small-scale study carried out by student nurses revealed ward curtains to be a source of contaminants and bacteria, including MRSA. Patients and medical staff can contaminate and be contaminated by bacteria which may be a source of cross-infection. Recommendations from the study included the promotion of further research in this area and more frequent laundering of curtains.

Is there a risk of cross-infection from laundered reusable bedpads?

The risk of cross-infection from reusable incontinence bedpads was assessed by determining their microbial content after one night's use by incontinent adults and after laundering using the standard foul wash procedure specified by the NHS Executive (NHS E, 1995) (which includes heat disinfection at 71 degrees C for 3 minutes). Measurements were made on a total of 145 bedpads from five different product designs. It was found that effective laundering destroyed all known pathogenic organisms, although some commensal flora were isolated in small numbers (mean 12.2 colony forming units/ml). It is concluded that laundering reusable incontinence pads using the foul wash procedure leaves pads safe for multiple patient reuse with no demonstrable risk of cross-infection.

The potential for increased risk of infection due to the reuse of convective air-warming/cooling coverlets

BACKGROUND

The use of convective air warming and/or cooling for the prevention of hypothermia or to induce hypothermia is growing rapidly. To date, there is no information available as to the potential risks for infection associated with either the post-surgical reuse or the repositioning of coverlets closer to the wound. We hypothesized that use of coverlets either intra- or postoperatively leads to increased contamination.

METHODS

The bacterial contamination of commercially available coverlets before (control group, n = 10) and after patient application (n = 18) was investigated. From 3 predetermined sites, 1 cm x 2 cm pieces of coverlet were removed and analyzed for bacterial contamination.

RESULTS

Even prior to use, coverlet samplings provided identifiable contamination (3 out of 30 sites, 10%), but this could be within our study's sampling error. Nevertheless, following clinical use the frequency of contamination was considerably increased; 17 out of 57 sampled sites (31.5%) elicited contamination (P < 0.05, Fisher's exact test).

CONCLUSION

This study demonstrates that the use of the coverlets, intra- or postoperatively, can lead to significant bacterial contamination. It is concluded that it is not advisable to reuse coverlets for multiple clinical applications.

Washing machine usage in remote aboriginal communities

The use of washing machines was investigated in two remote Aboriginal communities in the Anangu Pitjantjatjara homelands. The aim was to look both at machine reliability and to investigate the health aspect of washing clothes. A total of 39 machines were inspected for wear and component reliability every three months over a one-year period. Of these, 10 machines were monitored in detail for water consumption, hours of use and cycles of operation. The machines monitored were Speed Queen model EA2011 (7 kg washing load) commercial units. The field survey results suggested a high rate of operation of the machines with an average of around 1,100 washing cycles per year (range 150 and 2,300 cycles per year). The results were compared with available figures for the average Australian household. A literature survey, to ascertain the health outcomes relating to washing clothes and bedding, confirmed that washing machines are efficient at removal of bacteria from clothes and bedding but suggested that recontamination of clothing after washing often negated the prior removal. High temperature washing (> 60 degrees C) appeared to be advantageous from a health perspective. With regards to larger organisms, while dust mites and body lice transmission between people would probably be decreased by washing clothes, scabies appeared to be mainly transmitted by body contact and thus transmission would be only marginally decreased by the use of washing machines.

Effect of sun-drying and chemical disinfection on contaminated cleaning cloth

In domestic environment, cross-contamination by contaminated cleaning cloth represents an infection hazard. Could disinfectant use, detergent wash and rinse, and proper sun-drying be a panacea for cross-contamination? This is the fact-finding goal of this work. A sterilized towel (66.5 cm) was used to mop the eating tables of Nnamdi Azikiwe University cafeteria for 3 days, then aseptically collected and cut into six equal size, each for: estimation of total bacterial count; determination of the effects of detergent, sun-drying strength Ringer's solution was used as neutralizing medium. Seven organisms, Escherichia Coli, Staphylococcus aureus, Proteus. Bacillus, Klebsiella, and pseudomonas species were isolated from the mop. The total bacterial count was 2.9 x 10(12) cfu/cm2. However, detergent washing cum sun-drying proved effective in reducing, to acceptable standards, the bacterial numbers and types. Disinfectant use gave a second best result. The present hygienic practices in student's cafeteria and other similar places in Nigeria and elsewhere (where mop is not properly washed and sufficiently sun-dried before re-use) may not be quite healthy after all.

Observations on mattress covers: results of a pilot study

Samples of covers from three commercially available mattresses were examined in the laboratory using test methods originally devised for testing surgical dressings. These revealed that although the covers shared many common features, there were differences in the conformability and tensile properties which may be of some clinical relevance. The study also confirmed that with some minor modifications, the experimental techniques used would be suitable for a future, more comprehensive review of mattress performance. In a separate investigation designed to examine the consequences of a failure of a mattress cover, the bioburden of a foam core removed from a damaged cover revealed the presence of very large numbers of microorganism, well in excess of 10(10) per gram of foam which could act as a recevoir of contamination and thus a source of cross infection.