Survival and transmission of community-associated methicillin-resistant Staphylococcus aureus from fomites

Microbiological assessment of ready-to-eat foods and drinking water sources as a potential vehicle of bacterial pathogens in northern India

Foodborne illnesses caused by the consumption of contaminated foods have frequent occurrences in developing countries. The incorporation of contaminated water in food processes, preparation, and serving is directly linked to several gastrointestinal infections. Keeping in view, this study was conducted to assess the microbial quality of both drinking water sources and commonly consumed fresh ready-to-eat (RTE) foods in the region. The drinking water samples from water sources and consumer points, as well as food samples from canteens, cafes, hotels, and restaurants, were collected for the microbiological analysis. Fifty-five percent (n = 286) of water samples were found to be positive for total coliforms with MPN counts ranging from 3 to 2600 (100 ml) -1. E. coli was detected in nearly 30% of the total water samples. Overall, 65% tap water samples were found unsatisfactory, followed by submersible (53%), filter (40%), and WTP (30%) sources. Furthermore, the examination of RTE foods (n = 80) found that 60% were of unsatisfactory microbial quality with high aerobic plate counts. The salads were the most contaminated category with highest mean APC 8.3 log CFU/g followed by pani puri, chats, and chutneys. Presence of coliforms and common enteropathogens was observed in both water and food samples. The detected isolates from the samples were identified as Enterobacter spp., Klebsiella spp., Pseudomonas aeruginosa, Salmonella spp., Shigella spp., and Staphylococcus spp. Based on these findings, microbiological quality was found compromised and this may pose hazard to public health. This exploratory study in the Punjab region also suggests that poor microbiological quality of water sources can be an important source of contamination for fresh uncooked RTE foods, thus transferring pathogens to the food chain. Therefore, only safe potable drinking water post-treatment should be used at all stages.

Drug preparation, injection-related infections, and harm reduction practices among a national sample of individuals entering treatment for opioid use disorder

BACKGROUND

The rise in injection drug use in the USA has led to an increase in injection site infections. We performed a national survey of people who use drugs to evaluate common drug use preparation, harm reduction practices, and experiences with injection site infections.

METHODS

A survey was disseminated to members of the Survey of Key Informants' Patients Program from 2021 to 2022 and distributed to patients 18 years or older newly entering one of 68 substance use disorder treatment programs across the USA with a primary diagnosis of an opioid use disorder. Participants were surveyed about practices when preparing and using drugs, along with self-reported infections and drug use complications.

RESULTS

1289 participants responded to the survey. Sexually transmitted infections were common, with 37.6% reporting ever having had any sexually transmitted infection. Injection-associated infections had affected 63.4% of participants who had ever used injection drugs. Many respondents reported not seeking professional medical assistance for infection management, including 29% draining abscesses without seeking medical care and 22.8% obtaining antibiotics through non-healthcare sources. Non-sterile injection practices included sharing needles with others who were febrile or ill (18%), using needles previously used to drain wounds/abscesses (9.9%) for subsequent injection drug use, and licking needles (21.2%).

CONCLUSION

Patients entering treatment for opioid use disorder reported a high burden of infectious diseases. A number of easily-modifiable high risk behaviors for developing injection-related infections were identified. Efforts are needed to disseminate targeted harm reduction education to PWID on how to reduce their risks for injection-related infections.

Experimental Acquisition, Maintenance, and Transmission of Methicillin-Resistant Staphylococcus aureus by the Common Bed Bug, Cimex lectularius

Here, we fed bed bugs through a membrane contaminated with methicillin-resistant Staphylococcus aureus (MRSA) at a concentration naturally present on human skin. We then determined the amount of viable MRSA present on their surface and internally over a period of 7 days. We also determined whether bed bugs that fed through the contaminated membrane could transmit MRSA to an uncontaminated membrane when taking a second blood meal 7 days later. Bed bugs acquired MRSA both externally on the cuticle surface as well as internally when feeding. MRSA was found to persist for 7 days both externally and internally in some bed bugs. Furthermore, MRSA replicated internally but not externally. Most importantly, bed bugs were able to transmit MRSA to an uncontaminated membrane feeder in 2 of 3 trials. These findings provide the first experimental support for the hypothesis that bed bugs may contribute to the transmission of MRSA in some settings.

Infection prevention-how can we prevent transmission of community-onset methicillin-resistant Staphylococcus aureus?

BACKGROUND

Staphylococcus aureus is a versatile organism, capable of existing as a commensal organism while also possessing pathogenic potential. The emergence of clinically and genetically distinct strains of methicillin-resistant S. aureus (MRSA), termed community-onset MRSA (CO-MRSA), resulted in an epidemic of invasive and skin and soft tissue infections (SSTI) in otherwise healthy individuals without traditional risk factors. Colonization with S. aureus is a risk factor for developing infection and also a source of transmission to close contacts. Outbreaks of S. aureus SSTI have been described in crowded settings and within households. Thus, preventive strategies are essential to interrupt recurrent infections.

OBJECTIVES

The objective of this narrative review is to provide a comprehensive, evidence-based approach to prevent transmission of CO-MRSA. We highlight key clinical trials that emphasize the importance of household and environmental S. aureus colonization in propagating household transmission. Finally, we highlight research priorities to prevent S. aureus infection.

SOURCES

We cite primary literature from peer-reviewed publications as sources for this review.

CONTENT

Our recommended approach to the management of individuals presenting with skin abscesses includes optimal treatment of the initial infection and hygiene education. Decolonization measures should be recommended for individuals with recurrent SSTIs or whose household members have SSTIs. Targeted decolonization with topical antimicrobials should be prescribed to all affected individuals within the household.

IMPLICATIONS

S. aureus infections result in substantial mortality and morbidity because of the high incidence of recurrent skin infections. Although current decolonization strategies are beneficial, interventions are often costly to families and effectiveness wanes over time. Results from a recently completed trial evaluating integrated periodic decolonization and household environmental hygiene will further add to our understanding of what constitutes a sustainable decolonization approach. In addition, novel preventive strategies are being developed such as S. aureus vaccines, lytic agents, probiotics, microbiota transplants, and phage therapy.

In vitro study on the transmission of multidrug-resistant bacteria from textiles to pig skin

BACKGROUND

The survival of microorganisms on textiles and specifically on healthcare professionals' (HCP) attire has been demonstrated in several studies. The ability of microorganisms to adhere and remain on textiles for up to hours or days raises questions as to their possible role in transmission from textile to skin via HCP to patients.

AIM

To evaluate the presence, survival and transmission of different multidrug-resistant bacteria (MDRB) from HCP attire onto skin.

METHODS

Three MDRB [methicillin-resistant Staphylococcus aureus (MRSA); vancomycin-resistant Enterococcus faecium (VRE); carbapenem-resistant Klebsiella pneumoniae, CRKP)] were inoculated on textiles from scrubs (60% cotton-40% polyester) and white coat (100% cotton) at concentrations of 108 colony-forming units (CFU), 105 CFU, and 103 CFU per mL. The inoculation of swatches was divided in time intervals of 1 min, 5 min, 15 min, 30 min, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. At the end of each period, textiles were imprinted onto pig skins and each skin square was inverted onto three different selective chromogenic media. Growth from the pig skin squares was recorded for the 3 MDRB at the three above concentrations, for the whole length of the 6-h experiment.

RESULTS

MRSA was recovered from pig skins at all concentrations for the whole duration of the 6-h study. VRE was recovered from the concentration of 108 CFU/mL for 6 h and from 105 CFU/mL for up to 3 h, while showing no growth at 103 CFU/mL. CRKP was recovered from 108 CFU/mL for 6 h, up to 30 min from 105 CFU/mL and for 1 min from the concentration of 103 CFU/mL.

CONCLUSION

Evidence from the current study shows that MRSA can persist on textiles and transmit to skin for 6 h even at low concentrations. The fact that all MDRB can be sustained and transferred to skin even at lower concentrations, supports that textiles are implicated as vectors of bacterial spread.

In Vivo Pathogenicity of Methicillin-Susceptible Staphylococcus aureus Strains Carrying Panton-Valentine Leukocidin Gene

Toxin-producing Staphylococcus aureus strains posing a potential risk for public health have long been a topic of scientific research. Effects of Panton-Valentine leukocidin (PVL) on tissue destruction mechanisms and activities of inflammatory cells were presented in animal models of pneumonia and skin infections induced by PVL-producing S. aureus strains. This study aimed to demonstrate the in vivo pathogenicity of PVL-producing S. aureus strains isolated from some foodstuffs, which can be a potential risk to public health. PVL-positive methicillin-susceptible S. aureus (MSSA) strains M1 and YF1B-b isolated from different foodstuffs and a PVL-positive MSSA strain HT480 (positive control) were administered to New Zealand rabbits. Blood samples were harvested three and six hours after the intratracheal inoculation. Lung tissue samples were collected for gross and microscopic exams and immunohistochemical (IHC) demonstration of IL-6, IL8, IL-10, and TNF-α expressions. Serum cytokine levels were also measured by ELISA. The strains isolated from lung tissue samples were confirmed by pulsed-field gel electrophoresis. The development of acute necrotising pneumonia and a significant elevation in IL-6, IL-8, IL-10, and TNF-α expressions demonstrated the significance of foodborne PVL-positive MSSA strains in public health for the first time.

Effect of Surface Porosity on SARS-CoV-2 Fomite Infectivity

Previous reports indicated the low stability of severe actute respiratory syndrome coronovirus 2 (SARS-CoV-2) on various porous surfaces, but the role of porosity was unclear because there was no direct comparison between porous and nonporous solids of the same chemistry. Through comparing pairs of solids with very similar chemistry, we find that porosity is important: porous glass has a much lower infectivity than nonporous glass. However, porosity is not sufficient to lower infectivity; permeability, which is the ability of a liquid to move through a material, is the important parameter. We show this by comparing a pair of porous CuO coatings where the pores are accessible in one case and inaccessible in the other case. When the pores are inaccessible, the infectivity remains similar to that for nonporous solids. Thus, for both glass and CuO, it is the access to porosity that decreases the infectivity of extracted liquid droplets. Having established the importance of permeability, there is the open question of the mechanism of changing the infectivity of SARS-CoV-2. Several hypotheses are possible, such as increasing the difficulty of extracting the virus from the solid, changing the drying time, increasing the surface area of active ingredient, etc. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) measurements show that less viral DNA is extracted from a permeable surface, suggesting that the virus becomes trapped in the pores. Finally, we consider the effect of drying. We show that permeability and the water contact angle on the solid have effects on the drying time of a contaminated droplet, which may in turn affect infectivity.

Transparent Anti-SARS-CoV-2 and Antibacterial Silver Oxide Coatings

Transparent antimicrobial coatings can maintain the aesthetic appeal of surfaces and the functionality of a touch-screen while adding the benefit of reducing disease transmission. We fabricated an antimicrobial coating of silver oxide particles in a silicate matrix on glass. The matrix was grown by a modified Stöber sol-gel process with vapor-phase water and ammonia. A coating on glass with 2.4 mg of Ag2O per mm2 caused a reduction of 99.3% of SARS-CoV-2 and >99.5% of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus compared to the uncoated glass after 1 h. We envisage that screen protectors with transparent antimicrobial coatings will find particular application to communal touch-screens, such as in supermarkets and other check-out or check-in facilities where a number of individuals utilize the same touch-screen in a short interval.

Infectious Complications of Injection Drug Use

The opioid overdose epidemic is one of the leading causes of death in adults. Its devastating effects have included not only a burgeoning overdose crisis but also multiple converging infectious diseases epidemics. The use of both opioids and other substances through intravenous (IV) administration places individuals at increased risks of infectious diseases ranging from invasive bacterial and fungal infections to human immunodeficiency virus (HIV) and viral hepatitis. In 2012, there were 530,000 opioid use disorder (OUD)-related hospitalizations in the United States (US), with $700 million in costs associated with OUD-related infections. The scale of the crisis has continued to increase since that time, with hospitalizations for injection drug use-related infective endocarditis (IDU-IE) increasing by as much as 12-fold from 2010 to 2015. Deaths from IDU-IE alone are estimated to result in over 7,260,000 years of potential life lost over the next 10 years. There have been high-profile injection-related HIV outbreaks, and injection drug use (IDU) is now the most common risk factor for hepatitis C virus (HCV). As this epidemic continues to grow, clinicians in all aspects of medical care are increasingly confronted with infectious complications of IDU. This review will describe the pathogenesis, clinical syndromes, epidemiology, and models of treatment for common infectious complications among persons who inject drugs (PWIDs).

Current pharmacotherapy for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia

INTRODUCTION

Currently, several antibiotics are active against methicillin-resistant Staphylococcus aureus (MRSA) and can be used for the treatment of pneumonia. They show great variability in terms of antibiotic class, indication, pharmacodynamic/pharmacokinetic properties, type of available formulations, spectrum of activity against bacteria other than MRSA, and toxicity profile.

AREAS COVERED

In this narrative review, the authors discuss the characteristics of currently available agents for the treatment of MRSA pneumonia.

EXPERT OPINION

The availability of different agents with anti-MRSA activity, and approved for the treatment of pneumonia can allow a personalized approach for any given patient based on the severity of the disease, the setting of occurrence, the patient's baseline risk of toxicity and drug interactions, and the possibility of oral therapy whenever early discharge or outpatient treatment are possible. Although some gray areas still remain, like the lack of high certainty evidence on the efficacy of some old agents and on the precise role of companion agents with toxin inhibitory activity in the case of necrotizing pneumonia, the frequent availability of different treatment choices, each with peculiar characteristics, is already allowing an important step toward a precision medicine approach for the treatment of MRSA pneumonia.

Pathogenicity and virulence of Staphylococcus aureus

Staphylococcus aureus is one of the most frequent worldwide causes of morbidity and mortality due to an infectious agent. This pathogen can cause a wide variety of diseases, ranging from moderately severe skin infections to fatal pneumonia and sepsis. Treatment of S. aureus infections is complicated by antibiotic resistance and a working vaccine is not available. There has been ongoing and increasing interest in the extraordinarily high number of toxins and other virulence determinants that S. aureus produces and how they impact disease. In this review, we will give an overview of how S. aureus initiates and maintains infection and discuss the main determinants involved. A more in-depth understanding of the function and contribution of S. aureus virulence determinants to S. aureus infection will enable us to develop anti-virulence strategies to counteract the lack of an anti-S. aureus vaccine and the ever-increasing shortage of working antibiotics against this important pathogen.

Public Buses Decontamination by Automated Hydrogen Peroxide Aerosolization System

BACKGROUND: Public transportation has been linked to an increase in the risk of coronavirus disease 2019 transmission. The effective decontamination system using aerosolized hydrogen peroxide can mitigate the transmission risk from using public transportation. AIM: The aim of this study was to develop and validate an effective decontamination system for public transport. METHODS: The experimental research was performed in 13 inter-city public buses. The aerosol generator with ultrasonic atomizer was used in the experiment. The validation process for disinfection was conducted using both a chemical indicator (CI) and spore discs biological indicator (inoculated with 106 Geobacillus stearothermophilus enclosed in glassine envelopes). The CIs and biological indicators were marked by number and placed in nine locations on each bus. The decontamination cycle was developed by analyzed of various aerosolized and decomposition period. Both concentrations of hydrogen peroxide, 5% and 7%, were used for comparison. RESULTS: In an aerosolized period, both concentrations of hydrogen peroxide at 30 min were effective for sporicidal 6-log reductions. The decontamination cycle totaled 100 min, based on a 70 min average decomposition time. CONCLUSIONS: The automated hydrogen peroxide aerosolized system is a highly effective and safe method of decontaminating public buses.

Methicillin-Resistant Staphylococcus aureus Nasal Colonization Among Health Care Workers of a Tertiary Hospital in Ecuador and Associated Risk Factors

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to most of the commonly used antibiotics and is therefore a public health issue. Colonization with MRSA is a risk factor for infection or transmission.

Purpose

To determine the prevalence of colonization with Staphylococcus aureus (SA) and MRSA strains in health care workers (HCWs) at a tertiary hospital in Ecuador and to determine the risk factors associated with carriage.

Methods

Out of a cohort of 3800 HCWs, 481 individuals from different hospital departments were randomly selected, and a single nasal swab was collected. Detection of SA and MRSA was carried out with the LightCycler^® MRSA Advanced Test. A questionnaire was performed that gathered demographic and occupational information of the participants to determine risk factors for MRSA colonization. Statistical analysis was performed with univariate and multivariate analysis and the R-software version 4.0.2.

Results

Colonization with SA and MRSA occurred in respectively 23.7% (95% CI, 22.7–24.6) and 5% (95% CI, 3.39–7.58) of the individuals. The multivariate analysis showed that being older in age (OD 1.09) and being male (OD 2.78) were risk factors for SA and MRSA colonization (p-value < 0.001). Previous use of antibiotics or the use of nasal ointments diminished the colonization rates of SA (24% versus 3.7% and 10.1% respectively).

Conclusion

About 20% of the HCWs who were colonized with SA were colonized with MRSA, representing a risk for nosocomial infections and hospital outbreaks. Active monitoring and a decolonization treatment of the HCWs can reduce these risks.

The trend of environmental and clinical methicillin-resistant Staphylococcus aureus in a hospital in Taiwan: Impact of USA300

BACKGROUND

The environment may facilitate transmission of health care-associated methicillin-resistant Staphylococcus aureus (MRSA) and the pathogen is frequently shed by patients. However, the molecular characteristics and genetic relatedness between clinical and environmental MRSA isolates remain largely unclear in the clinical setting.

METHODS

A total of 100 hospitalized patients with MRSA infection and 25 hospitalized patients without MRSA infection were enrolled in a medical center, Taiwan in 2019. Environmental and clinical MRSA isolates were characterized by antibiotic susceptibility testing and molecular methods.

RESULTS

In the study, we detected 17 MRSA isolates in the environment that surrounded 15 MRSA-infected patients and one environmental MRSA isolate from one patient without MRSA infection. The molecular analysis revealed a high genetic diversity within either environmental or clinical MRSA isolates, while the USA300 clone (pulsotype AI, SCCmec IV, ST8, PVL-positive) accounts for 39% (7/18) of environmental and 33% (7/21) of clinical MRSA isolates. Moreover, 13 of the 15 MRSA-infected patients had identical paired clinical-environmental MRSA isolates, which exhibited indistinguishable genetic relatedness and highly similar antibiotic susceptibility phenotype, suggesting a possible transmission cycle of MRSA in the hospital.

CONCLUSIONS

The environmental MRSA was closely linked to MRSA isolated from patients, suggesting that the environment may act as a reservoir of MRSA. Besides, the USA300 MRSA has become a major clone in the hospital setting. An effective and rigorous approach to environmental cleaning and decontamination is suggested to eradicate MRSA in the hospital.

A Longitudinal Study of Adult Patients with Staphylococcus aureus Bacteremia over 11 Years in Korea

BACKGROUND

The temporal changes in the Staphylococcus aureus genotypes causing S. aureus bacteremia (SAB) and the corresponding clinical changes over the last decade in South Korea are rarely investigated.

METHODS

A longitudinal study of adult SAB patients was conducted in a large referral hospital in Seoul, South Korea. Adult monomicrobial SAB patients were enrolled between August 2008 and December 2018. Genotyping was performed by multilocus sequence typing (MLST) and staphylococcal protein A (spa) typing. Trends in changes were identified by linear regression analysis.

RESULTS

Of 1782 adult SAB patients, the blood isolates of 1,778 (99.8%) and 1,634 (91.7%) were determined to be MLST and spa type, respectively. ST5 (-2.626%/year) and ST239 (-0.354%/year) decreased during the study period (P < 0.001 for both), but ST72 (2.009%/yr)-and ST8 (0.567%/yr) increased (P < 0.001 for both). The most common genotype was changed from ST5 in 2008 (44.9%) to ST72 in 2018 (36.3%). Panton-Valentine leukocidin-positive spa-t008-MRSA (USA300) was found in 28.6%. Central venous catheter (CVC)-related SAB (-2.440%/yr) and persistent SAB (-1.016%/yr) decreased, but mortality and recurrence rates were unchanged.

CONCLUSION

Over the last decade, the hospital clones ST5 and ST239 have been replaced by community genotype ST72. This was associated with decreased CVC-related and persistent SAB. Increased USA300 was observed in community and hospital settings. Further research is required to identify the reasons for the ST72 epidemic and predict the impending epidemic of ST8 strains, including USA300.

Surface texture limits transfer of S. aureus, T4 bacteriophage, influenza B virus and human coronavirus

Spread of pathogens on contaminated surfaces plays a key role in disease transmission. Surface technologies that control pathogen transfer can help control fomite transmission and are of great interest to public health. Here, we report a novel bead transfer method for evaluating fomite transmission in common laboratory settings. We show that this method meets several important criteria for quantitative test methods, including reasonableness, relevancy, resemblance, responsiveness, and repeatability, and therefore may be adaptable for standardization. In addition, this method can be applied to a wide variety of pathogens including bacteria, phage, and human viruses. Using the bead transfer method, we demonstrate that an engineered micropattern limits transfer of Staphylococcus aureus by 97.8% and T4 bacteriophage by 93.0% on silicone surfaces. Furthermore, the micropattern significantly reduces transfer of influenza B virus and human coronavirus on silicone and polypropylene surfaces. Our results highlight the potential of using surface texture as a valuable new strategy in combating infectious diseases.

Methicillin Resistant Staphylococcus aureus and public fomites: a review

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

Optimizing Contact Precautions to Curb the Spread of Antibiotic-resistant Bacteria in Hospitals: A Multicenter Cohort Study to Identify Patient Characteristics and Healthcare Personnel Interactions Associated With Transmission of Methicillin-resistant Staphylococcus aureus

Background

Healthcare personnel (HCP) acquire antibiotic-resistant bacteria on their gloves and gowns when caring for intensive care unit (ICU) patients. Yet, contact precautions for patients with methicillin-resistant Staphylococcus aureus (MRSA) remains controversial despite existing guidelines. We sought to understand which patients are more likely to transfer MRSA to HCP and to identify which HCP interactions are more likely to lead to glove or gown contamination.

Methods

This was a prospective, multicenter cohort study of cultured HCP gloves and gowns for MRSA. Samples were obtained from patients’ anterior nares, perianal area, and skin of the chest and arm to assess bacterial burden.

Results

Among 402 MRSA-colonized patients with 3982 interactions, we found that HCP gloves and gowns were contaminated with MRSA 14.3% and 5.9% of the time, respectively. Contamination of either gloves or gowns occurred in 16.2% of interactions. Contamination was highest among occupational/physical therapists (odds ratio [OR], 6.96; 95% confidence interval [CI], 3.51, 13.79), respiratory therapists (OR, 5.34; 95% CI, 3.04, 9.39), and when any HCP touched the patient (OR, 2.59; 95% CI, 1.04, 6.51). Touching the endotracheal tube (OR, 1.75; 95% CI, 1.38, 2.19), bedding (OR, 1.43; 95% CI, 1.20, 1.70), and bathing (OR, 1.32; 95% CI, 1.01, 1.75) increased the odds of contamination. We found an association between increasing bacterial burden on the patient and HCP glove or gown contamination.

Conclusions

Gloves and gowns are frequently contaminated with MRSA in the ICU. Hospitals may consider using fewer precautions for low-risk interactions and more for high-risk interactions and personnel.

Development of a silver-based dual-function antimicrobial laundry additive and textile coating for the decontamination of healthcare laundry

AIMS

To repurpose a silver-based antimicrobial textile coating product (Micro-Fresh 1911) as a dual-function antimicrobial laundry additive and textile coating.

METHODS AND RESULTS

Survival of Escherichia coli or Staphylococcus aureus type and clinical isolates in a domestic 40°C wash was assessed with and without soiling and biological detergent. Washing with 2% w/v silver additive (wash phase) reduced E. coli and S. aureus by 7·14-8·08 log₁₀ and no cross-contamination was observed. Under dirty conditions, 0·5% silver additive in the rinse phase of a wash with biological detergent reduced E. coli and S. aureus by 7·98-8·40 log₁₀ (0·00-1·42 log₁₀ cross contamination). BS EN ISO 20645:2004 and BS EN ISO 20743:2013 methods were used to assess the antimicrobial activity of polycotton washed with 2% w/v silver additive against S. aureus and E. coli. The treated polycotton was antimicrobial against E. coli and S. aureus type and clinical isolates and remains active after at least one further wash cycle at 40 or 73°C.

CONCLUSIONS

The silver additive exhibits antimicrobial activity in a 40°C domestic wash, preventing cross contamination onto clean textiles and depositing an antimicrobial coating onto polycotton.

SIGNIFICANCE AND IMPACT OF THE STUDY

The survival of micro-organisms on healthcare uniforms during domestic laundering presents a potential risk of contaminating the home, cross-contamination of other clothing within the wash and transmitting potential pathogens back into healthcare settings via contaminated uniforms. Silver may be useful as an antimicrobial laundry additive to decontaminate healthcare laundry washed at low temperatures in domestic and industrial settings, to therefore reduce the potential risk of transmitting micro-organisms within the domestic and clinical environments.

The role of textiles as fomites in the healthcare environment: a review of the infection control risk

BACKGROUND

Infectious diseases are a significant threat in both healthcare and community settings. Healthcare associated infections (HCAIs) in particular are a leading cause of complications during hospitalisation. Contamination of the healthcare environment is recognised as a source of infectious disease yet the significance of porous surfaces including healthcare textiles as fomites is not well understood. It is currently assumed there is little infection risk from textiles due to a lack of direct epidemiological evidence. Decontamination of healthcare textiles is achieved with heat and/or detergents by commercial or in-house laundering with the exception of healthcare worker uniforms which are laundered domestically in some countries. The emergence of the COVID-19 pandemic has increased the need for rigorous infection control including effective decontamination of potential fomites in the healthcare environment. This article aims to review the evidence for the role of textiles in the transmission of infection, outline current procedures for laundering healthcare textiles and review studies evaluating the decontamination efficacy of domestic and industrial laundering.

METHODOLOGY

Pubmed, Google Scholar and Web of Science were searched for publications pertaining to the survival and transmission of microorganisms on textiles with a particular focus on the healthcare environment.

RESULTS

A number of studies indicate that microorganisms survive on textiles for extended periods of time and can transfer on to skin and other surfaces suggesting it is biologically plausible that HCAIs and other infectious diseases can be transmitted directly through contact with contaminated textiles. Accordingly, there are a number of case studies that link small outbreaks with inadequate laundering or infection control processes surrounding healthcare laundry. Studies have also demonstrated the survival of potential pathogens during laundering of healthcare textiles, which may increase the risk of infection supporting the data published on specific outbreak case studies.

CONCLUSIONS

There are no large-scale epidemiological studies demonstrating a direct link between HCAIs and contaminated textiles yet evidence of outbreaks from published case studies should not be disregarded. Adequate microbial decontamination of linen and infection control procedures during laundering are required to minimise the risk of infection from healthcare textiles. Domestic laundering of healthcare worker uniforms is a particular concern due to the lack of control and monitoring of decontamination, offering a route for potential pathogens to enter the clinical environment. Industrial laundering of healthcare worker uniforms provides greater assurances of adequate decontamination compared to domestic laundering, due to the ability to monitor laundering parameters; this is of particular importance during the COVID-19 pandemic to minimise any risk of SARS-CoV-2 transmission.

How long can nosocomial pathogens survive on textiles? A systematic review

Aims: Healthcare-associated infections linked to contaminated textiles are rare but underline their potential role as a source for transmission. The aim of the review was to summarize the experimental evidence on the survival and persistence of the different types of nosocomial pathogens on textiles.

Methods: A literature search was performed on MedLine. Original data on the survival of bacteria, mycobacteria, and fungi and persistence of viruses on textiles were evaluated.

Results: The survival of bacteria at room temperature was the longest on polyester (up to 206 days), whereas it was up to 90 days for some species on cotton and mixed fibers. Only low inocula of 100 CFU were found on all types of textiles with a short survival time of ≤3 days. Most bacterial species survived better at elevated air humidity. The infectivity of viruses on textiles is lost much faster at room temperature, typically within 2–4 weeks.

Conclusions: Contaminated textiles or fabrics may be a source of transmission for weeks. The presence of pathogens on the coats of healthcare workers is associated with the presence of pathogens on their hands, demonstrating the relevance of textile contamination in patient care.

Spectrum of virucidal activity from ultraviolet to infrared radiation

The COVID-19 pandemic has sparked a demand for safe and highly effective decontamination techniques for both personal protective equipment (PPE) and hospital and operating rooms. The gradual lifting of lockdown restrictions warrants the expansion of these measures into the outpatient arena. Ultraviolet C (UVC) radiation has well-known germicidal properties and is among the most frequently reported decontamination techniques used today. However, there is evidence that wavelengths beyond the traditional 254 nm UVC - namely far UVC (222 nm), ultraviolet B, ultraviolet A, visible light, and infrared radiation - have germicidal properties as well. This review will cover current literature regarding the germicidal effects of wavelengths ranging from UVC through the infrared waveband with an emphasis on their activity against viruses, and their potential applicability in the healthcare setting for general decontamination during an infectious outbreak.

Occurrence of potentially pathogenic bacteria on shared bicycles

BACKGROUND

Shared bicycles offer the potential to be sources for interindividual bacterial community transfer. However, the overall ecology of the bacterial community persisting on the shared bicycles is still unknown.

METHODS

We used 16S rRNA sequencing techniques in combination with multiple bioinformatic analyses to profile bacterial communities on shared bicycle handles and saddles in selected five locations in a metropolitan area (Chengdu, China). Samples of air around shared bicycles were collected as a control.

RESULTS

We demonstrate that the species richness and diversity of samples from shared bicycles are significantly higher than those of surrounding air samples. Taxonomical composition indicates that community structure of shared bicycle handles and saddles are also different. Additionally, high occurrence of pathogenic or potentially pathogenic genera is found on the surfaces of shared bicycles, including Sphingomonas, Acinetobacter, Staphylococcus, and Cutibacterium. Moreover, PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) further verifies that bacteria involved in signaling pathways related to human diseases are at significantly higher levels in shared bicycle samples, while bacteria associated with environmental information processing pathways are at significantly higher levels in the air samples.

CONCLUSION

Our results reveal the profiles of bacterial communities on shared bicycles, and suggest that potentially pathogenic bacteria may impair human health through shared bicycles, especially in susceptible individuals. Notably, this investigation will prompt the public to pay more attention to the management of bicycle sharing programs worldwide, and it also provides research basis for the government to formulate corresponding public health policies.

Analysis of the CodY RNome reveals RsaD as a stress-responsive riboregulator of overflow metabolism in Staphylococcus aureus

In Staphylococcus aureus, the transcription factor CodY modulates the expression of hundreds of genes, including most virulence factors, in response to the availability of key nutrients like GTP and branched-chain amino acids. Despite numerous studies examining how CodY controls gene expression directly or indirectly, virtually nothing is known about the extent to which CodY exerts its effect through small regulatory RNAs (sRNAs). Herein, we report the first set of sRNAs under the control of CodY. We reveal that staphylococcal sRNA RsaD is overexpressed >20-fold in a CodY-deficient strain in three S. aureus clinical isolates and in S. epidermidis. We validated the CodY-dependent regulation of rsaD and demonstrated that CodY directly represses rsaD expression by binding the promoter. Using a combination of molecular techniques, we show that RsaD posttranscriptionally regulates alsS (acetolactate synthase) mRNA and enzyme levels. We further show that RsaD redirects carbon overflow metabolism, contributing to stationary phase cell death during exposure to weak acid stress. Taken together, our data delineate a role for CodY in controlling sRNA expression in a major human pathogen and indicate that RsaD may integrate nutrient depletion and other signals to mount a response to physiological stress experienced by S. aureus in diverse environments.

Longitudinal, strain-specific Staphylococcus aureus introduction and transmission events in households of children with community-associated meticillin-resistant S aureus skin and soft tissue infection: a prospective cohort study

BACKGROUND

Devising effective, targeted approaches to prevent recurrent meticillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infection requires an understanding of factors driving MRSA acquisition. We comprehensively defined household longitudinal, strain-level S aureus transmission dynamics in households of children with community-associated MRSA skin and soft tissue infection.

METHODS

From 2012-15, otherwise healthy paediatric patients with culture-confirmed, community-onset MRSA infections were recruited for the Household Observation of MRSA in the Environment (HOME) prospective cohort study from hospitals and community practices in metropolitan St Louis (MO, USA). Children with health-care-related risk factors were excluded, as determined by evidence of recent hospital admission, an invasive medical device, or residence in a long-term care facility. Household contacts (individuals sleeping in the home ≥four nights per week) and indoor dogs and cats were also enrolled. A baseline visit took place at the index patient's primary home, followed by four quarterly visits over 12 months. At each visit, interviews were done and serial cultures were collected, to detect S aureus from three anatomic sites of household members, two anatomic sites on dogs and cats, and 21 environmental surfaces. Molecular typing was done by repetitive-sequence PCR to define distinct S aureus strains within each household. Longitudinal, multivariable generalised mixed-effects logistic regression models identified factors associated with S aureus acquisition.

FINDINGS

Across household members, pets, and environmental surfaces, 1267 strain acquisition events were observed. Acquisitions were driven equally by 510 introductions of novel strains into households and 602 transmissions within households, each associated with distinct factors. Frequent handwashing decreased the likelihood of novel strain introduction into the household (odds ratio [OR] 0·86, credible interval [CrI] 0·74-1·01). Transmission recipients were less likely to own their homes (OR 0·77, CrI 0·63-0·94) and were more likely to share bedrooms with strain-colonised individuals (OR 1·33, CrI 1·12-1·58), live in homes with higher environmental S aureus contamination burden (OR 3·97, CrI 1·96-8·20), and report interval skin and soft tissue infection (OR 1·32, CrI 1·07-1·64). Transmission sources were more likely to share bath towels (OR 1·25, CrI 1·01-1·57). Pets were often transmission recipients, but rarely the sole transmission source.

INTERPRETATION

The household environment plays a key role in transmission, a factor associated with skin and soft tissue infection. Future interventions should inclusively target household members and the environment, focusing on straightforward changes in hand hygiene and household sharing behaviours.

FUNDING

National Institutes of Health, Agency for Healthcare Research and Quality, Children's Discovery Institute, Burroughs Wellcome Foundation, Defense Advanced Research Projects Agency.

MRSA dynamic circulation between the community and the hospital setting: New insights from a cohort study

Dissemination of methicillin-resistant-Staphylococcus aureus/(MRSA) is a worldwide concern both in hospitals [healthcare-associated-(HA)-MRSA] and communities [community-associated-(CA)-MRSA]. Knowledge on when and where MRSA colonization is acquired and what clones are involved is necessary, to focus efforts for prevention of hospital-acquired MRSA-infections.

METHODS

A prospective/longitudinal cohort study was performed in eight Argentina hospitals (Cordoba/ October-December/2014). Surveillance cultures for MRSA (nose-throat-inguinal) were obtained on admission and at discharge. MRSA strains were genetically typed as CA-MRSA_G and HA-MRSA_G genotypes.

RESULTS

Overall, 1419 patients were screened and 534 stayed at hospital for ≥3 days. S. aureus admission prevalence was 30.9% and 4.2% for MRSA. Overall MRSA acquisition rate was 2.3/1000 patient-days-at-risk with a MRSA acquisition prevalence of 1.96% (95%CI: 1.0%-3.4%); 3.2% of patients were discharged back to community with MRSA. CA-MRSA_G accounted for 84.6% of imported, 100.0% of hospital-acquired and 94% of discharged MRSA strains. Most imported and acquired MRSA strains belonged to two major epidemic CA-MRSA clones spread in Argentina: PFGEtypeI-ST5-IVa-t311-PVL⁺ and PFGEtypeN/ST30-IVc-t019-PVL⁺.

CONCLUSIONS

CA-MRSA clones, particularly ST5-IV-PVL⁺ and ST30-IV-PVL⁺, with main reservoir in the community, not only enter but also are truly acquired within hospital, causing healthcare-associated-hospital-onset infections, having a transmission capacity greater or similar than HA-MRSA_G. This information is essential to develop appropriate MRSA infection prevention-control programs, considering hospital and community.

Prevention Strategies for Recurrent Community-Associated Staphylococcus aureus Skin and Soft Tissue Infections

PURPOSE OF REVIEW

Staphylococcus aureus skin and soft tissue infections (SSTI) are a major source of morbidity. More than half of patients experiencing SSTI will have at least one recurrent infection. These infections frequently cluster in households. Given the burden these infections pose to patients and healthcare, prevention strategies are of major clinical importance and represent an active area of research. Bacterial colonization is frequently an early and critical step in the pathogenesis of infection. As such, strategies to prevent reinfection have aimed to decrease staphylococcal colonization of the skin and mucus membranes, a process referred to as decolonization.

RECENT FINDINGS

Treatment of acute SSTI with incision and drainage and systemic antibiotics is the mainstay of therapy for healing of the acute infection. Systemic antibiotics also provide benefit through reduced incidence of recurrent SSTI. Education for patients and families regarding optimization of personal and household hygiene measures, and avoidance of sharing personal hygiene items, is an essential component in prevention efforts. For patients experiencing recurrent SSTI, or in households in which multiple members have experienced SSTI, decolonization should be recommended for all household members. A recommended decolonization regimen includes application of intranasal mupirocin and antiseptic body washes with chlorhexidine or dilute bleach water baths. For patients who continue to experience recurrent SSTI, periodic decolonization should be considered. Personal decolonization with topical antimicrobials and antiseptics reduces the incidence of recurrent S. aureus SSTI. Future avenues for investigation include strategies for household environmental decontamination as well as manipulation of the host microbiota.

Characterizing the molecular epidemiology of Staphylococcus aureus across and within fitness facility types

BACKGROUND

Staphylococcus aureus is a common bacterium found in the nose and throat of healthy individuals, and presents risk factors for infection and death. We investigated environmental contamination of fitness facilities with S. aureus in order to determine molecular types and antibiotic susceptibility profiles of contaminates that may be transmitted to facility patrons.

METHODS

Environmental swabs (n = 288) were obtained from several fitness facilities (n = 16) across Northeast Ohio including cross-fit type facilities (n = 4), traditional iron gyms (n = 4), community center-based facilities (n = 5), and hospital-associated facilities (n = 3). Samples were taken from 18 different surfaces at each facility and were processed within 24 h using typical bacteriological methods. Positive isolates were subjected to antibiotic susceptibility testing and molecular characterization (PVL and mecA PCR, and spa typing).

RESULTS

The overall prevalence of S. aureus on environmental surfaces in the fitness facilities was 38.2% (110/288). The most commonly colonized surfaces were the weight ball (62.5%), cable driven curl bar, and CrossFit box (62.5%), as well as the weight plates (56.3%) and treadmill handle (50%). Interestingly, the bathroom levers and door handles were the least contaminated surfaces in both male and female restroom facilities (18.8%). Community gyms (40.0%) had the highest contamination prevalence among sampled surfaces with CrossFit (38.9%), traditional gyms (38.9%), and hospital associated (33.3%) contaminated less frequently, though the differences were not significant (p = 0.875). The top spa types found overall were t008 (12.7%), t267 (10.0%), t160, t282, t338 (all at 5.5%), t012 and t442 (4.5%), and t002 (3.6%). t008 and t002 was found in all fitness facility types accept Crossfit, with t267 (25%), t548, t377, t189 (all 10.7%) the top spa types found within crossfit. All samples were resistant to benzylpenicillin, with community centers having significantly more strains resistant to oxacillin (52.8%), erythromycin (47%), clindamycin (36%), and ciprofloxacin (19%). Overall, 36.3% of isolates were multidrug resistant.

CONCLUSIONS

Our pilot study indicates that all facility types were contaminated by S. aureus and MRSA, and that additional studies are needed to characterize the microbiome structure of surfaces at different fitness facility types and the patrons at these facilities.

Current and future treatment options for community-associated MRSA infection

INTRODUCTION

Community-associated MRSA (CA-MRSA) represents a global epidemic which beautifully encapsulates the fascinating ability of bacterial organisms to adapt quickly on an evolutionary basis to the extreme selective pressure of antibiotic exposure. In stark contrast to Healthcare-associated MRSA (HA-MRSA), it has become apparent that CA-MRSA is less straight forward of a challenge in terms of controlling its transmission, and has forced clinicians to adjust empiric management of clinical syndromes such as skin and soft tissue infection (SSTI) as well as pneumonia.

AREAS COVERED

This review details the history and epidemiology of CA-MRSA, while covering both current and future treatment options that are and may be available to clinicians. The authors reviewed both historic and more recent literature on this ever-evolving topic.

EXPERT OPINION

While development of new anti-MRSA agents should be encouraged, the importance of antimicrobial stewardship in the battle to stay ahead of the curve with regards to the ongoing control of the MRSA epidemic should be emphasised.

Acquisition and persistence of strain-specific methicillin-resistant Staphylococcus aureus and their determinants in community nursing homes

Background

Nursing home residents are frequently colonized with various strains of methicillin-resistant Staphylococcus aureus (MRSA) but the intra-facility dynamics of strain-specific MRSA remains poorly understood. We aimed at identifying and quantifying the associations between acquisition and carriage of MRSA strains and their potential risk factors in community nursing homes using mathematical modeling.

Methods

The data was collected during a longitudinal MRSA surveillance study in six nursing homes in South Central Wisconsin. MRSA cultures were obtained from subjects every 3 months for up to one year. MRSA isolates were subsequently strain-typed by pulsed-field gel electrophoresis (PFGE), and their genetic similarity was established based on the Dice coefficients. Bayesian network analysis, logistic regression and elastic net were used to quantify the associations between acquisition and carriage of MRSA strains discriminated at 80% and 95% strain similarity thresholds and potentially modifiable resident characteristics including previous antibiotic exposure, comorbidity, medical devices, chronic wounds, functional and cognitive status and recent hospitalizations.

Results

Absence of severe cognitive impairment as well as presence of a wound, device and severe comorbidity was associated with elevated probability of USA100 carriage although there was a variation based on the combination of those risk factors. Residents with severe comorbidity and cognitive status and presence of device and wound were identified as certain carriers of USA100 in our sample. Residents with a chronic wound were more likely to carry USA100 MRSA (OR = 2.77, 95% CI = 1.37–5.87). Functional status was identified as an important determinant of carriage of USA100 and USA300 strains. Comorbidity and cognitive status were the two factors associated with carriage of all clonal groups in the study (USA100, USA300 and USA1200).

Conclusions

The combination of Bayesian network analysis, logistic regression and elastic net can be used to identify associations between acquisition and carriage of MRSA strains and their potential risk factors in the face of scarce data. The revealed associations may be used to generate hypothesis for further study of determinants of acquisition and carriage of selected MRSA subtypes and to better inform infection control efforts in community nursing homes.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2837-3) contains supplementary material, which is available to authorized users.

Transfer of bacteriophage MS2 and fluorescein from N95 filtering facepiece respirators to hands: Measuring fomite potential

Contact transmission of pathogens from personal protective equipment is a concern within the healthcare industry. During public health emergency outbreaks, resources become constrained and the reuse of personal protective equipment, such as N95 filtering facepiece respirators, may be needed. This study was designed to characterize the transfer of bacteriophage MS2 and fluorescein between filtering facepiece respirators and the wearer's hands during three simulated use scenarios. Filtering facepiece respirators were contaminated with MS2 and fluorescein in droplets or droplet nuclei. Thirteen test subjects performed filtering facepiece respirator use scenarios including improper doffing, proper doffing and reuse, and improper doffing and reuse. Fluorescein and MS2 contamination transfer were quantified. The average MS2 transfer from filtering facepiece respirators to the subjects' hands ranged from 7.6-15.4% and 2.2-2.7% for droplet and droplet nuclei derived contamination, respectively. Handling filtering facepiece respirators contaminated with droplets resulted in higher levels of MS2 transfer compared to droplet nuclei for all use scenarios (p = 0.007). MS2 transfer from droplet contaminated filtering facepiece respirators during improper doffing and reuse was greater than transfer during improper doffing (p = 0.008) and proper doffing and reuse (p = 0.042). Droplet contamination resulted in higher levels of fluorescein transfer compared to droplet nuclei contaminated filtering facepiece respirators for all use scenarios (p = 0.009). Fluorescein transfer was greater for improper doffing and reuse (p = 0.007) from droplet contaminated masks compared to droplet nuclei contaminated filtering facepiece respirators and for improper doffing and reuse when compared improper doffing (p = 0.017) and proper doffing and reuse (p = 0.018) for droplet contaminated filtering facepiece respirators. For droplet nuclei contaminated filtering facepiece respirators, the difference in MS2 and fluorescein transfer did not reach statistical significance when comparing any of the use scenarios. The findings suggest that the results of fluorescein and MS2 transfer were consistent and highly correlated across the conditions of study. The data supports CDC recommendations for using proper doffing techniques and discarding filtering facepiece respirators that are directly contaminated with secretions from a cough or sneeze.

Swine exposure and methicillin-resistant Staphylococcus aureus infection among hospitalized patients with skin and soft tissue infections in Illinois: A ZIP code-level analysis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA), a bacterial pathogen, is a predominant cause of skin and soft tissue infections (SSTI) in the United States. Swine-production facilities have been recognized as potential environmental reservoirs of MRSA. To better understand how swine production may contribute to MRSA infection, we evaluated the association between MRSA infection among SSTI inpatients and exposure measures derived from national swine inventory data.

METHODS

Based on adjusted odds ratios from logistic regression models, we evaluated the association between swine exposure metrics and MRSA infections among all Illinois inpatient hospitalizations for SSTI from January 2008 through July 2011. We also assessed if swine exposures had greater association with suspected community-onset MRSA (CO-MRSA) compared to suspected hospital-onset MRSA (HO-MRSA). Exposures were estimated using the Farm Location and Agricultural Production Simulator, generating the number of farms with greater than 1000 swine per residential ZIP code and the residential ZIP code-level swine density (swine/km²).

RESULTS

For every increase in 100 swine/km² within a residential ZIP code, the adjusted OR (aOR) for MRSA infection was 1.36 (95% CI: 1.28-1.45). For every additional large farm (i.e., >1000 swine) per ZIP code, the aOR for MRSA infection was 1.06 (95% CI: 1.04-1.07). The aOR for ZIP codes with any large farms compared to those with no large farms was 1.24 (95% CI: 1.19-1.29). We saw no evidence of an increased association for CO-MRSA compared to HO-MRSA with either continuous exposure metric (aORs=0.99), and observed inconsistent results across exposure categories.

CONCLUSIONS

These publicly-available, ecological exposure data demonstrated positive associations between swine exposure measures and individual-level MRSA infections among SSTI inpatients. Though it is difficult to draw definitive conclusions due to limitations of the data, these findings suggest that the risk of MRSA may increase based on indirect environmental exposure to swine production. Future research can address measurement error related to these data by improving exposure assessment precision, increased specification of MRSA strain, and better characterization of specific environmental exposure pathways.

Comparison of survivability of Staphylococcus aureus and spores of Aspergillus niger on commonly used floor materials

BACKGROUND

The survivability of Staphylococcus aureus and spores of Aspergillus niger was compared on 5 common floor materials.

METHODS

Floor materials were inoculated with a known concentration of S aureus and spores of A niger on day 0. Their survivability was measured on days, 2, 7, 14, and 28 by bulk rinsate method and enumerated using culture-based method.

RESULTS

The difference in change of S aureus levels was statistically significant for all tested days (P < .001) for all floor materials. Vinyl composition tile (VCT) and porcelain tile (PT) had statistically similar survivability and differed statistically from carpets. On both VCT and PT, positive growth for S aureus occurred by day 2 (1-1.7 log₁₀), declined slightly (0.1 to -0.2 log₁₀) by day 7, and remained positive until day 28. However, S aureus was undetected by day 7 on both carpets. A niger spores were undetected on residential broadloom carpet and rubber-backed commercial carpet after day 2 but survived on VCT, PT, and wood until day 28.

CONCLUSIONS

Floor materials with hard and smooth surfaces, such as VCT and PT, can allow survival of S aureus and A niger for up to 4 weeks. It may imply that floor materials can play a major role in preserving microbial contaminants in the built environment.

Effect of Temperature and Nutrient Concentration on Survival of Foodborne Pathogens in Deciduous Fruit Processing Environments for Effective Hygiene Management

Temperature and good sanitation practices are important factors for controlling growth of microorganisms. Fresh produce is stored at various temperatures to ensure quality and to prolong shelf life. When foodborne pathogens survive and grow on fresh produce at storage temperatures, then additional control strategies are needed to inactivate these pathogens. The aim of this study was to determine how temperatures associated with deciduous fruit processing and storage facilities (0.5, 4, and 21°C) affect the growth and/or survival of Escherichia coli O157:H7, Listeria monocytogenes , Salmonella enterica subsp. enterica serovar Typhimurium, and Staphylococcus aureus under different nutrient conditions (nutrient rich and nutrient poor) and on simulated contact surfaces (vinyl coupons). Information on the growth and survival of foodborne pathogens at specific deciduous fruit processing and storage temperatures (0.5°C) is not available. All pathogens except E. coli O157:H7 were able to survive on vinyl coupons at all temperatures. L. monocytogenes proliferated under both nutrient conditions independent of temperature. S. aureus was the pathogen least affected by nutrient conditions. The survival of foodborne pathogens on the vinyl coupons, a model system for studying surfaces in fruit preparation and storage environments, indicates the potential for cross-contamination of deciduous fruit products under poor sanitation conditions. Foodborne pathogens that can proliferate and survive at various temperatures under different nutrient conditions could lead to fruit cross-contamination. Temperature mismanagement, which could allow pathogen proliferation in contaminated fruit packing houses and storage environments, is a concern. Therefore, proper hygiene and sanitation practices, removal of possible contaminants, and proper food safety management systems are needed to ensure food safety.

Identifying conditions for elimination and epidemic potential of methicillin-resistant Staphylococcus aureus in nursing homes

BACKGROUND

Residents of nursing homes are commonly colonized with methicillin-resistant Staphylococcus aureus (MRSA) but there is a limited understanding of the dynamics and determinants of spread in this setting. To address this gap, we sought to use mathematical modeling to assess the epidemic potential of MRSA in nursing homes and to determine conditions under which non-USA300 and USA300 MRSA could be eliminated or reduced in the facilities.

METHODS

Model parameters were estimated from data generated during a longitudinal study of MRSA in 6 Wisconsin nursing homes. The data included subject colonization status with strain-specific MRSA collected every 3 months for up to 1 year. Deterministic and stochastic co-colonization and single-strain models were developed to describe strain-specific dynamics of MRSA in these facilities. Basic reproduction numbers of strain-independent MRSA, non-USA300 and USA300 MRSA were estimated numerically. The impact of antibiotic use in the past 3 months on the prevalence of strain-specific MRSA and associated basic reproduction numbers were evaluated.

RESULTS

Our models predicted that MRSA would persist in Wisconsin nursing homes, and non-USA300 would remain the dominant circulating strain. MRSA eradication was theoretically achievable by elimination of MRSA-positive admissions over the course of years. Substantial reductions in MRSA prevalence could be attained through marked increase in clearance rates or reduction in MRSA-positive admissions sustained over years. The basic reproduction number of strain-independent MRSA was 0.18 (95 % CI = 0.13-0.23). Recent antibiotic use increased the prevalence of strain-specific MRSA and associated basic reproduction numbers, but was unlikely to lead to an outbreak.

CONCLUSIONS

Based on our model, MRSA elimination from nursing homes, while theoretically possible, was unlikely to be achieved in practice. Decolonization therapy that can sustain higher clearance rates or lower MRSA-positive introductions over years may reduce strain-specific prevalence of MRSA in the facilities, and antibiotic stewardship may contribute to this effort. Large-scale MRSA outbreaks were unlikely in this setting.

Antisuperbug Cotton Fabric with Excellent Laundering Durability

Multidrug-resistant superbugs are currently a severe threat to public health. Here, we report a novel kind of antisuperbug material prepared by irradiation induced graft polymerization of 1-butyl-3-vinyl imidazole chloride onto cotton fabric. The reduction of superbugs on this fabric is higher than 99.9%. Attributed to the strong covalent bonding between the graft chains and the cellulose macromolecules, the antisuperbug performance did not decrease even after 150 equiv of domestic laundering cycles. Covalent bonding also prevented the release of the antibacterial groups during application and guarantees the safety of the material, which was proved by animal skin irritation and acute oral toxicity tests.

Transfer and Decontamination of S. aureus in Transmission Routes Regarding Hands and Contact Surfaces

Hand hygiene, cleaning and disinfection are pre-requirements for hygiene management in hospital settings and the food industry. In order to facilitate risk management, different contamination scenarios and interventions need to be evaluated. In the present study data on transfer rates and reductions of Staphylococcus aureus were provided in an experimental set-up using artificial skin. Using this methodology, test persons were not exposed with pathogenic bacteria. An exposure assessment model was developed and applied to evaluate different contamination routes and hygiene interventions. The transfer rates of S. aureus from inoculated VITRO-SKIN^® to fomites were calculated from blotting series. The VITRO-SKIN^® was more prone to spread bacteria than fomites. When different surfaces were cleaned, the reduction of S. aureus varied between <1 and 7 log CFU. It could not be concluded that a certain coupon material, cleaning agent, cleaning wipe, soiling or humidity consistently resulted in a high or low reduction of S. aureus. The reduction of S. aureus and E. coli during hand washing was evaluated on artificial skin, VITRO-SKIN^®. The reduction of E. coli on VITRO-SKIN^® was similar to the log reduction obtained when washing human hands. The S. aureus count on a human hand was both calculated in different scenarios describing different contamination routes starting from a contaminated hand using the exposure assessment model, and measured on an experimental setup using VITRO-SKIN^® for validation. A linear relationship was obtained between the analysed level of S. aureus and the calculated level. However, the calculated levels of S. aureus on the VITRO-SKIN^® in the scenarios were 1–1.5 log lower than the analysed level. One of the scenarios was used to study the effect of interventions like hand washing and cleaning of surfaces.

Models to predict prevalence and transition dynamics of methicillin-resistant Staphylococcus aureus in community nursing homes

BACKGROUND

Recent spread of USA300 methicillin-resistant Staphylococcus aureus (MRSA) to nursing homes has been of particular concern. We sought to predict the ultimate prevalence of USA300 and non-USA300 MRSA and to examine the influence of potential risk factors on MRSA acquisition in community nursing homes.

METHODS

The data were collected during a longitudinal MRSA surveillance study that involved 449 residents in 6 community nursing homes in Wisconsin. The subjects were screened every 3 months for up to 1 year. Markov chain models were employed to predict strain-specific prevalence of MRSA at steady state, and to assess the influence of potential risk factors, including recent hospitalizations, invasive medical devices, and antibiotic exposure on MRSA acquisition rates and average duration of colonization.

RESULTS

At steady state, 20% (95% confidence interval [CI], 15%-25%) of residents were predicted to remain colonized with non-USA300 and 4% (95% CI, 2%-7%) with USA300 MRSA. Residents who used antibiotics during the previous 3 months were twice more likely to acquire MRSA than those who did not (acquisition rates, 0.052; 95% CI, 0.038-0.075 and 0.025; 95% CI, 0.018-0.037, respectively).

CONCLUSIONS

Non-USA300 was predicted to remain the dominant MRSA strain in community nursing homes. The higher rate of MRSA acquisition among residents with recent antibiotic exposure suggests that antibiotic stewardship may reduce MRSA colonization in this setting.

Treatment Failure Outcomes for Emergency Department Patients with Skin and Soft Tissue Infections

Introduction

Skin and soft tissue infections (SSTIs) are commonly evaluated in the emergency department (ED). Our objectives were to identify predictors of SSTI treatment failure within one week post-discharge in patients with cutaneous abscesses, as well as to identify predictors of recurrence within three months in that proportion of participants.

Methods

This was a sub-analysis of a parent study, conducted at two EDs, evaluating a new, nucleic acid amplification test (NAAT) for Staphylococcus aureus in ED patients. Patients ≥18 years receiving incision and drainage (I&D) were eligible. Patient-reported outcome data on improvement of fever, swelling, erythema, drainage, and pain were collected using a structured abstraction form at one week, one month, and three months post ED visit.

Results

We enrolled 272 participants (20 from a feasibility study and 252 in this trial), of which 198 (72.8%) completed one-week follow up. Twenty-seven additional one-week outcomes were obtained through medical record review rather than by the one-week follow-up phone call. One hundred ninety-three (73%) patients completed either the one- or three-month follow up. Most patients recovered from their initial infection within one week, with 10.2% of patients reporting one-week treatment failure. The odds of treatment failure were 66% lower for patients who received antibiotics following I&D at their initial visit. Overall SSTI recurrence rate was 28.0% (95% CI [21.6%–34.4%]) and associated with contact with someone infected with methicillin resistant S. aureus (MRSA), previous SSTI history, or clinician use of wound packing.

Conclusion

Treatment failure was reduced by antibiotic use, whereas SSTI recurrence was associated with prior contact, SSTI, or use of packing.

Epidemiology of Methicillin-Susceptible Staphylococcus aureus in a Neonatology Ward

OBJECTIVE

In-hospital transmission of methicillin-susceptible Staphylococcus aureus (MSSA) among neonates remains enigmatic. We describe the epidemiology of MSSA colonization and infection in a 30-bed neonatal ward.

DESIGN

Multimodal outbreak investigation

SETTING

A public 800-bed tertiary care university hospital in Switzerland

METHODS

Investigations in 2012-2013, triggered by a MSSA infection cluster, included prospective MSSA infection surveillance, microbiologic screening of neonates and environment, onsite observations, and a prospective cohort study. MSSA isolates were characterized by pulsed-field gel electrophoresis (PFGE) and selected isolates were examined for multilocus sequence type (MLST) and virulence factors.

RESULTS

Among 726 in 2012, 30 (4.1%) patients suffered from MSSA infections including 8 (1.1%) with bacteremia. Among 655 admissions in 2013, 13 (2.0%) suffered from MSSA infections including 2 (0.3%) with bacteremia. Among 177 neonates screened for S. aureus carriage, overall 77 (44%) tested positive. A predominant PFGE-1-ST30 strain was identified in 6 of 30 infected neonates (20%) and 30 of 77 colonized neonates (39%). This persistent clone was pvl-negative, tst-positive and belonged to agr group III. We found no environmental point source. MSSA carriage was associated with central vascular catheter use but not with a particular midwife, nurse, physician, or isolette. Observed healthcare worker behavior may have propagated transmission via hands and fomites. Despite multimodal interventions, clonal transmission and colonization continued and another clone, PFGE-6-ST5, became predominant.

CONCLUSIONS

Hospital-acquired MSSA clones represent a high proportion of MSSA colonization but not MSSA infections in neonate inpatients. In contrast to persisting MSSA, transmission infection rates decreased concurrently with interventions. It remains to be established whether eradication of hospital-acquired MSSA strains would reduce infection rates further.

Persistent Environmental Contamination with USA300 Methicillin-Resistant Staphylococcus aureus and Other Pathogenic Strain Types in Households with S. aureus Skin Infections

Objective.

To understand the genotypic spectrum of environmental contamination ofStaphylococcus aureusin households and its persistence

Design.

Prospective longitudinal cohort investigation.

Setting.

Index participants identified at 2 academic medical centers.

Participants.

Adults and children withS. aureusskin infections and their household contacts in Los Angeles and Chicago.

Methods.

Household fomites were surveyed for contamination at baseline and 3 months. All isolates underwent genetic typing.

Results.

We enrolled 346 households, 88% of which completed the 3-month follow-up visit.S. aureusenvironmental contamination was 49% at baseline and 51% at 3 months. Among households with a USA300 methicillin-resistantS. aureus(MRSA) body infection isolate, environmental contamination with an indistinguishable MRSA strain was 58% at baseline and 63% at 3 months. Baseline factors associated with environmental contamination by the index subject’s infection isolate were body colonization by any household member with the index subject’s infection isolate at baseline (odds ratio [OR], 10.93 [95% confidence interval (CI), 5.75–20.79]), higher housing density (OR, 1.47 [95% CI, 1.10–1.96]), and more frequent household fomite cleaning (OR, 1.62 [95% CI, 1.16–2.27]). Household environmental contamination with the index subject’s infection strain at 3 months was associated with USA300 MRSA and a synergistic interaction between baseline environmental contamination and body colonization by any household member with the index subject’s infection strain.

Conclusions.

We found that infectingS. aureusisolates frequently persisted environmentally in households 3 months after skin infection. Presence of pathogenicS. aureusstrain type in the environment in a household may represent a persistent reservoir that places household members at risk of future infection.

Infect Control Hosp Epidemiol2014;35(11):1373–1382

Diversity of bacterial communities of fitness center surfaces in a U.S. metropolitan area

Public fitness centers and exercise facilities have been implicated as possible sources for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial community residing on the surfaces in these indoor environments is still unknown. In this study, we investigated the overall bacterial ecology of selected fitness centers in a metropolitan area (Memphis, TN, USA) utilizing culture-independent pyrosequencing of the 16S rRNA genes. Samples were collected from the skin-contact surfaces (e.g., exercise instruments, floor mats, handrails, etc.) within fitness centers. Taxonomical composition revealed the abundance of Firmicutes phyla, followed by Proteobacter and Actinobacteria, with a total of 17 bacterial families and 25 bacterial genera. Most of these bacterial genera are of human and environmental origin (including, air, dust, soil, and water). Additionally, we found the presence of some pathogenic or potential pathogenic bacterial genera including Salmonella, Staphylococcus, Klebsiella, and Micrococcus. Staphylococcus was found to be the most prevalent genus. Presence of viable forms of these pathogens elevates risk of exposure of any susceptible individuals. Several factors (including personal hygiene, surface cleaning and disinfection schedules of the facilities) may be the reasons for the rich bacterial diversity found in this study. The current finding underscores the need to increase public awareness on the importance of personal hygiene and sanitation for public gym users.

Staphylococcus aureus skin infection recurrences among household members: an examination of host, behavioral, and pathogen-level predictors

BACKGROUND

Many patients suffer from recurrent Staphylococcus aureus infections, but there are few data examining recurrence predictors.

METHODS

We followed adults and children after treatment for S. aureus skin infections and their household contacts in Los Angeles and Chicago. We surveyed subjects for S. aureus body colonization, household fomite contamination, and behavioral and clinical factors at baseline and 3 and 6 months later. Using repeated measures modeling, we examined host, pathogen, behavioral, and clinical factors associated with recurrence.

RESULTS

Among 330 index subjects, 182 (55%) were infected with an isolate of the USA300 methicillin-resistant S. aureus (MRSA) genetic background. Recurrences occurred in 39% by month 3 and 51% by month 6. Among 588 household contacts, 10% reported a skin infection by month 3 and 13% by month 6. Among index subjects, recurrence was associated with (P < .05) Los Angeles site, diabetes, recent hospitalization, recent skin infection, recent cephalexin use, and household S. aureus or MRSA fomite contamination; recurrence was inversely associated with recent contact sports participation. In the multivariate model, independent predictors of recurrence in index patients were recent hospitalization, household MRSA fomite contamination, and lack of recent contact sports participation. Among household contacts, independent predictors of subsequent skin infection were Chicago site, antibiotic use in the prior year, and skin infection in the prior 3 months.

CONCLUSIONS

In our longitudinal study, patients with a S. aureus skin infection were more likely to suffer a recurrence if household fomites were MRSA contaminated. Interventions to prevent recurrence may be enhanced by decontamination of household fomites.

Persistent environmental contamination with USA300 methicillin-resistant Staphylococcus aureus and other pathogenic strain types in households with S. aureus skin infections

OBJECTIVE

To understand the genotypic spectrum of environmental contamination of Staphylococcus aureus in households and its persistence.

DESIGN

Prospective longitudinal cohort investigation.

SETTING

Index participants identified at 2 academic medical centers.

PARTICIPANTS

Adults and children with S. aureus skin infections and their household contacts in Los Angeles and Chicago.

METHODS

Household fomites were surveyed for contamination at baseline and 3 months. All isolates underwent genetic typing.

RESULTS

We enrolled 346 households, 88% of which completed the 3-month follow-up visit. S. aureus environmental contamination was 49% at baseline and 51% at 3 months. Among households with a USA300 methicillin-resistant S. aureus (MRSA) body infection isolate, environmental contamination with an indistinguishable MRSA strain was 58% at baseline and 63% at 3 months. Baseline factors associated with environmental contamination by the index subject's infection isolate were body colonization by any household member with the index subject's infection isolate at baseline (odds ratio [OR], 10.93 [95% confidence interval (CI), 5.75-20.79]), higher housing density (OR, 1.47 [95% CI, 1.10-1.96]), and more frequent household fomite cleaning (OR, 1.62 [95% CI, 1.16-2.27]). Household environmental contamination with the index subject's infection strain at 3 months was associated with USA300 MRSA and a synergistic interaction between baseline environmental contamination and body colonization by any household member with the index subject's infection strain.

CONCLUSIONS

We found that infecting S. aureus isolates frequently persisted environmentally in households 3 months after skin infection. Presence of pathogenic S. aureus strain type in the environment in a household may represent a persistent reservoir that places household members at risk of future infection.