Household transmission of meticillin-resistant Staphylococcus aureus and other staphylococci

Bleach baths enhance skin barrier, reduce itch but do not normalize skin dysbiosis in atopic dermatitis

Studies have demonstrated that bleach baths improve atopic dermatitis (AD) severity; however, the effects on itch, skin barrier, and cutaneous microbial composition are less clear. We examined whether bleach baths reduce itch, normalize skin barrier function, reduce S. aureus absolute abundance, and increase microbial diversity in adults with AD who were colonized with S. aureus on their non-lesional skin. This was an open label, non-randomized, controlled trial performed at a single academic center. Fifteen AD and five non-atopic healthy controls (NA) were instructed to take two bleach baths (0.005% NaClO; 5-10 min duration) per week for a total of 12 weeks as add-on therapy. Adults 18 to 65 years (inclusive) with mild to severe AD were recruited with EASI score > 6.0, S. aureus culture positivity, access to a bathtub, and ability and willingness to maintain current topical or systemic treatments. They were evaluated at baseline (before bleach baths), 6 weeks, and 12 weeks after the intervention of twice-weekly bleach baths. Efficacy measurements included EASI as well as 5-D Pruritus and ItchyQoL™. Transepidermal water loss (TEWL) and stratum corneum (SC) integrity assay were performed to assess the skin barrier. Skin dysbiosis was measured by S. aureus cultivation, S. aureus abundance (qPCR of thermonuclease gene), and V1-V3 16S rRNA gene sequencing on non-lesional and lesional AD skin. After 12 weeks of bleach baths, 8/15 (53.3%) AD subjects achieved an EASI50 and a significant reduction in itch as measured by 5-D pruritus and Itchy QoL. Eighty-seven percent reported improvements in sleep quality. At study entry, AD subjects had higher non-lesional TEWL values than NA subjects, and only AD subjects experienced a reduction with bleach baths (p = 0.006). Similarly, SC integrity improved as early as 6 weeks after bleach baths in AD subjects. Notably, bleach baths had no significant effect on S. aureus culture-positivity, qPCR absolute abundance, or microbial diversity. The addition of twice-weekly bleach baths improves investigator-assessed AD severity, patient-reported pruritus and sleep as well as physiological measures of skin barrier function in adult AD subjects while having no effect on qualitative and quantitative measures of cutaneous S. aureus. Trial Registration: ClinicalTrials.gov Identifier: NCT01996150, Date of registration: November 27th, 2013.

Virulence Mechanisms of Staphylococcal Animal Pathogens

Staphylococci are major causes of infections in mammals. Mammals are colonized by diverse staphylococcal species, often with moderate to strong host specificity, and colonization is a common source of infection. Staphylococcal infections of animals not only are of major importance for animal well-being but have considerable economic consequences, such as in the case of staphylococcal mastitis, which costs billions of dollars annually. Furthermore, pet animals can be temporary carriers of strains infectious to humans. Moreover, antimicrobial resistance is a great concern in livestock infections, as there is considerable antibiotic overuse, and resistant strains can be transferred to humans. With the number of working antibiotics continuously becoming smaller due to the concomitant spread of resistant strains, alternative approaches, such as anti-virulence, are increasingly being investigated to treat staphylococcal infections. For this, understanding the virulence mechanisms of animal staphylococcal pathogens is crucial. While many virulence factors have similar functions in humans as animals, there are increasingly frequent reports of host-specific virulence factors and mechanisms. Furthermore, we are only beginning to understand virulence mechanisms in animal-specific staphylococcal pathogens. This review gives an overview of animal infections caused by staphylococci and our knowledge about the virulence mechanisms involved.

Inactivation of Salmonella, Shiga Toxin-producing E. coli, and Listeria monocytogenes in Raw Diet Pet Foods Using High-Pressure Processing

Pet food formulated with raw meat can pose health risks to pets and humans. High-pressure processing (HPP) was evaluated to achieve a 5-log reduction ofSalmonella,E. coliSTEC, andL. monocytogenesin commercial raw pet foods and maintain a 5-log reduction throughout post-HPP storage.Three formulation types that varied in the amounts of striated meat, organ meat, bone, seeds, and other ingredients (fruits, vegetables, and minor ingredients) designated as A-, S-, and R-formulations were used. Eight raw diet pet foods, consisting of three beef formulations (A-, S- and R-Beef), three chicken formulations (A-, S-, and R-Chicken), and two lamb formulations (A- and S-Lamb), were inoculated with 7 log CFU/g cocktails ofSalmonella,E. coliSTEC orL. monocytogenes, HPP at 586 MPa for 1-4 min, and stored refrigerated (4°C) or frozen (-10 to -18°C) for 21 days with microbiological analyses at various time intervals. A- formulations (20-46% meat, 42-68% organs, 0.9-1.3% seeds, and 10.7-11.1% fruits, vegetables, and minor ingredients) inoculated withSalmonellaand treated at 586 MPa for at least 2 min achieved a 5-log reduction 1 day post-HPP and maintained that inactivation level during frozen storage. A- and S-formulations inoculated withE. coliSTEC and treated at 586 MPa for at least 2 min achieved a 5-log reduction from day 6 of frozen storage. L. monocytogeneswas more HPP resistant thanSalmonellaandE. coliSTEC.S-formulations containing chicken or beef and stored frozen post-HPP had lower inactivation of L. monocytogenes compared to A-formulations containing chicken or beef. S-Lamb had higher frozen storage inactivation (5.95 ± 0.20 log CFU/g) compared to chicken (2.52 ± 0.38 log CFU/g) or beef (2.36 ± 0.48 log CFU/g). HPP coupled with frozen storage time was effective in achieving and maintaining a 5-log reduction ofSalmonellaandE. coliSTEC whileL. monocytogeneswas more resistant and requires further optimization to achieve a 5-log reduction.

Prevalence and antibiotic resistance of Staphylococcus aureus associated with a college-aged cohort: life-style factors that contribute to nasal carriage

Staphylococcus aureus is an opportunistic human pathogen that can frequently be found at various body locations, such as the upper respiratory tract, nostrils, skin, and perineum. S. aureus is responsible for causing a variety of conditions, which range from minor skin infections and food poisoning to life-threatening sepsis and endocarditis. Furthermore, S. aureus has developed resistance to numerous antimicrobial agents, which has made treatment of S. aureus infections difficult. In the present study, we examined lifestyle factors that could increase the likelihood of S. aureus carriage, the overall prevalence of S. aureus, as well as assessed the antibiotic resistance profiles of the S. aureus isolates among a population of college students. Five hundred nasal samples were collected and analyzed via selective growth media, coagulase and protein A testing, as well as polymerase chain reaction and DNA sequencing. One hundred four out of the 500 samples collected (21%) were identified as containing S. aureus. The S. aureus isolates were resistant to penicillin (74%), azithromycin (34%), cefoxitin (5%), ciprofloxacin (5%), tetracycline (4%), and trimethoprim (1%), but sensitive to gentamicin and rifampin. Lastly, we identified several lifestyle factors (i.e., pet exposure, time spent at the university recreational facility, musical instrument usage, and tobacco usage) positively correlated with S. aureus nasal colonization.

The Epidemiology of Animal-Associated Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) remains an important etiological factor of human and animal infectious diseases, causing significant economic losses not only in human healthcare but also in the large-scale farming sector. The constantly changing epidemiology of MRSA observed globally affects animal welfare and raises concerns for public health. High MRSA colonization rates in livestock raise questions about the meaning of reservoirs and possible transmission pathways, while the prevalence of MRSA colonization and infection rates among companion animals vary and might affect human health in multiple ways. We present the main findings concerning the circulation of animal-associated MRSA (AA-MRSA) in the environment and factors influencing the direction, mechanisms, and routes of its transmission. Studies have shown it that S. aureus is a multi-host bacterial pathogen; however, its adaptation mechanisms enabling it to colonize and infect both animal and human hosts are still rarely discussed. Finally, we elaborate on the most successful strategies and programs applied limiting the circulation of AA-MRSA among animals and humans. Although MRSA strains colonizing animals rarely infect humans, they undergo host-adaptive evolution enabling them to spread and persist in human populations.

The Type 7b Secretion System of S. aureus and Its Role in Colonization and Systemic Infection

Staphylococcus aureus bears a type 7b secretion system (T7bSS) that assembles in the bacterial envelope to promote the secretion of WXG-like proteins and toxic effectors bearing LXG domains. Cognate immunity proteins bind cytosolic effectors to mute their toxicity prior to secretion. T7b-secreted factors have been associated with the pathogenesis of staphylococcal disease and intraspecies competition. We identified earlier strain WU1, an S. aureus ST88 isolate that caused outbreaks of skin and soft tissue infections in mouse breeding facilities. WU1 was also found to persistently colonize the nasopharynx of animals, suggesting a strong host adaptation. In this manner, WU1 colonization and infectivity in mice resembles that of methicillin-sensitive and -resistant S. aureus strains in humans, where nasal carriage is a major risk factor for invasive infections. Here, animals were colonized with wild-type or T7-deficient WU1 strains or combinations thereof. Absence of the T7bSS did not affect colonization in the nasopharynx of animals, and although fluctuations were observed in weekly samplings, the wild-type strain did not replace the T7-deficient strain in cocolonization experiments. Bloodstream infection with a T7b-deficient strain resulted in enhanced survival and reduced bacterial loads and abscesses in soft tissues compared to infection with wild-type WU1. Together, experiments using a mouse-adapted strain suggest that the T7bSS of S. aureus is an important contributor to the pathogenesis of invasive disease.

Antimicrobial Resistance in Romania: Updates on Gram-Negative ESCAPE Pathogens in the Clinical, Veterinary, and Aquatic Sectors

Multidrug-resistant Gram-negative bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, and members of the Enterobacterales order are a challenging multi-sectorial and global threat, being listed by the WHO in the priority list of pathogens requiring the urgent discovery and development of therapeutic strategies. We present here an overview of the antibiotic resistance profiles and epidemiology of Gram-negative pathogens listed in the ESCAPE group circulating in Romania. The review starts with a discussion of the mechanisms and clinical significance of Gram-negative bacteria, the most frequent genetic determinants of resistance, and then summarizes and discusses the epidemiological studies reported for A. baumannii, P. aeruginosa, and Enterobacterales-resistant strains circulating in Romania, both in hospital and veterinary settings and mirrored in the aquatic environment. The Romanian landscape of Gram-negative pathogens included in the ESCAPE list reveals that all significant, clinically relevant, globally spread antibiotic resistance genes and carrying platforms are well established in different geographical areas of Romania and have already been disseminated beyond clinical settings.

Complete Genome Sequences of Bioluminescent Staphylococcus aureus Strains Xen31 and Xen36, Derived from Two Clinical Isolates

Here, we report complete genome sequences of two clinical isolates of Staphylococcus aureus, namely, Xen31 and Xen36, which have been genetically modified to express an optimized Photorhabdus luminescens luciferase operon. Xen31 and Xen36 are bioluminescent strains used widely for investigation of bacterial pathogenesis, drug discovery, and development of novel therapies.

A standardized instrument quantifying risk factors associated with bi-directional transmission of SARS-CoV-2 and other zoonotic pathogens: The COVID-19 human-animal interactions survey (CHAIS)

Similar to many zoonotic pathogens which transmit from animals to humans, SARS-CoV-2 (CoV-2), the virus responsible for the COVID-19 pandemic, most likely originated in Rhinolophus bats before spreading among humans globally. Early into the pandemic, reports of CoV-2 diagnoses in animals from various countries emerged. While most CoV-2 positive animals were confirmed to have been in close contact with CoV-2 positive humans, there has been a paucity of published evidence to-date describing risk factors associated with CoV-2 transmission among humans and animals. The COVID-19 Human-Animal Interactions Survey (CHAIS) was developed to provide a standardized instrument describing human-animal interactions during the pandemic and to evaluate behavioral, spatiotemporal, and biological risk factors associated with bi-directional zoonotic transmission of CoV-2 within shared environments, predominantly households with limited information about human-wildlife or human-livestock interactions. CHAIS measures four broad domains of transmission risk: 1) risk and intensity of infection in human hosts, 2) spatial characteristics of shared environments, 3) behaviors and human-animal interactions, and 4) susceptible animal subpopulations. Following the development of CHAIS, with a One Health approach, a multidisciplinary group of experts (n = 20) was invited to review and provide feedback on the survey for content validity. Expert feedback was incorporated into two final survey formats—an extended version and an abridged version for which specific core questions addressing zoonotic and reverse zoonotic transmission were identified. Both versions are modularized, with each section having the capacity to serve as independent instruments, allowing researchers to customize the survey based on context and research-specific needs. Further adaptations for studies seeking to investigate other zoonotic pathogens with similar routes of transmission (i.e. respiratory, direct contact) are also possible. The CHAIS instrument is a standardized human-animal interaction survey developed to provide important data on risk factors that guide transmission of CoV-2, and other similar pathogens, among humans and animals.

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The CHAIS instrument is a standardized instrument evaluating risk factors for bi-directional CoV-2 zoonotic transmission

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It evaluates settings where humans and animals share close contact, mainly households

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It is highly adaptable for investigating other zoonotic pathogens such as influenza viruses

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It will enable pooling of data across studies for meta-analyses to improve predictive models

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It can help inform public health prevention and mitigation measures

Consumer attitudes toward bacteriophage applications to pet food

This study used a two-part questionnaire to investigate consumer knowledge and attitudes toward bacteriophage applications in pet food, pet food safety, and environmental sustainability. Part 1 included questions about pet food safety, sustainability, and knowledge and attitudes toward bacteriophages. Next, participants reviewed educational materials about each, and Part 2 assessed if this increased knowledge of, or changed attitudes toward, bacteriophage application. Participants (n = 80), were recruited through Amazon Mechanical Turk (MT) (n = 45) and Social Media (SM) (n = 35). Mean responses in Part 1 and Part 2 were compared by paired t-tests, and mean responses between MT and SM were compared by t-tests. Participants reported pet food safety was important to them (combined proportion strongly agree or agree, mean ± SD) (75/80, 94%, MT 4.66 ± 0.60, SM 4.71 ± 0.95) and were most concerned with raw pet food safety (51/80, 64%, MT 3.88 ± 0.80, SM 3.17 ± 1.40). Participants rated environmental sustainability as important (61/80, 76%, MT 3.86 ± 0.94, SM 3.97 ± 0.66); however, it was not a strong driver of pet food purchasing (26/80, 33%, MT 3.31 ± 1.25, SM 2.82 ± 0.82). Overall, data showed an increase in knowledge of bacteriophages following a review of educational material. However, in the SM group, no statistically significant difference was observed in the comfort eating food with bacteriophage additives (SM Part 1 3.37 ± 1.05, SM Part 2 3.48 ± 1.12, p = 0.279), whereas the MT group did show an increase (MT Part 1 3.57 ± 1.01, MT Part 2 4.08 ± 0.92, p < 0.001). In the SM group, no statistically significant difference was observed in comfort feeding their pet food with bacteriophage additives (SM Part 1 3.40 ± 1.03, SM Part 2 3.45 ± 1.14, p = 0.571), whereas the MT group did show an increase (MT Part 1 3.57 ± 0.98, MT Part 2 4.31 ± 0.84, p < 0.001). The strongest objections related to safety concerns (20/53, 38%, MT 2.83 ± 0.96, SM 3.27 ± 0.84). These results demonstrate that despite increasing knowledge, there is still hesitancy among some consumers toward bacteriophage applications in pet food.

Risk factors for antimicrobial resistance among Staphylococcus isolated from pets living with a patient diagnosed with methicillin-resistant Staphylococcus aureus infection

It has been suggested that pets play a critical role in the maintenance of methicillin-resistant (MR) and multidrug-resistant (MDR) Staphylococcus spp. in the household. We examined risk factors for carriage of antimicrobial-resistant coagulase-positive staphylococci, with particular attention to Staphylococcus aureus and Staphylococcus pseudintermedius isolated from pets living in households of people diagnosed with methicillin-resistant S. aureus (MRSA) skin or soft-tissue infection. We analyzed data collected cross-sectionally from a study conducted in 2012 that evaluated the transmission of MRSA and other staphylococci from humans, their pets and the environment (Pets and Environmental Transmission of Staphylococci [PETS] study). We used unadjusted and adjusted stratified logistic regression analyses with household-clustered standard errors to evaluate the association between demographic, healthcare-related, contact-related and environmental risk factors and MDR Staphylococcus spp. isolated from dogs and cats. Staphylococcal isolates obtained from dogs (n = 63) and cats (n = 47) were included in these analyses. The use of oral or injectable antimicrobials by the pets during the prior year was the main risk factor of interest. Based on our results, 50% (12/24) of S. aureus, 3.3% (1/30) of S. pseudintermedius and 25% (14/56) of other coagulase-positive staphylococci (CPS) were determined to be MDR. S. aureus isolates were more likely to be MDR compared with S. pseudintermedius. We did not find a significant statistical association between the use of oral or injectable antimicrobials in the prior year and the presence of MDR bacteria. The results suggest that drivers of antimicrobial resistance in household staphylococci may vary by bacterial species, which could have implications for one health intervention strategies for staphylococci and inform the investigation of other reverse zoonoses, such as COVID-19.

Inanimate Surfaces as a Source of Hospital Infections Caused by Fungi, Bacteria and Viruses with Particular Emphasis on SARS-CoV-2

The carriers of nosocomial infections are the hands of medical personnel and inanimate surfaces. Both hands and surfaces may be contaminated as a result of contact with the patient, their body fluids, and touching contaminated surfaces in the patient's surroundings. Visually clean inanimate surfaces are an important source of pathogens. Microorganisms have properties thanks to which they can survive in unfavorable conditions, from a few days to several months. Bacteria, viruses and fungi are able to transmit from inanimate surfaces to the skin of the patient and the medical staff. These pathogens include SARS-CoV-2, which can survive on various types of inanimate surfaces, being a potential source of infection. By following the recommendations related to washing and disinfecting hands and surfaces, and using appropriate washing and disinfecting agents with a broad biocidal spectrum, high material compatibility and the shortest duration of action, we contribute to breaking the chain of nosocomial infections.

Transmission of Methicillin-Resistant Staphylococcus spp. from Infected Dogs to the Home Environment and Owners

Dogs with methicillin-resistant Staphylococcus spp. (MRS) infections often undergo treatment in their homes, interacting with their owners and surroundings. This close contact between dogs and owners may facilitate the interspecies transmission of MRS. Therefore, this study aimed to investigate the transmission of MRS from infected dogs to their owners and home environments. Seven households with dogs that had been diagnosed with methicillin-resistant S. pseudintermedius (MRSP) and one household with a dog with methicillin-resistant S. epidermidis (MRSE) participated in the study. Dogs, owners, and the home environments were screened for the presence of clinical MRS. A selection of 36 staphylococcal isolates were whole-genome sequenced and screened for resistance genes and virulence genes. Clinical MRS were primarily identified from the dogs and their immediate surroundings, but these were also detected in locations that were out of reach for the dogs, indicating indirect transmission. Two of eight owners carried clinical MRS in their nostrils, while one owner carried methicillin-susceptible S. pseudintermedius (MSSP). All clinical MRS were multi-resistant, and several possessed resistance genes that were not expressed phenotypically. Clinical MRSP persisted in the home environment for a prolonged period, despite infection recovery and one dog being euthanized. Regardless of the stable presence of MRSP in the surroundings, the owners in these homes remained negative, but tested positive for MSSP on three occasions.

The remarkable genetic relationship between Staphylococcus aureus isolates from hemodialysis patients and their household contacts: Homes as an important source of colonization and dissemination

Introduction

Staphylococcus aureus is a successful pathogen in hospital and community. Hemodialysis patients have high colonization rates. Interactions between them and their household contacts, are an opportunity to understand the S. aureus colonization between hospitals and community. This study aims to determine the clinical and epidemiological characteristics of S. aureus colonization in hemodialysis patients and their household contacts, as well as the genetic relationship between their isolates.

Methods

A cross-sectional study was conducted on hemodialysis patients from hospital-associated dialysis center in Medellín-Colombia, and their household contacts between 2019 and 2020. Colonization was assessed in the nostrils for household contacts and nostrils and skin around the catheter insertion for hemodialysis patients. Epidemiological information was obtained, and colonization was evaluated in their pets’ oral cavities. Bacterial identification and susceptibility were assessed using phenotypic and molecular methods. Molecular typing included SCCmec typing, pulsed-field gel electrophoresis (PFGE), spa typing, and virulence factor detection.

Results

Colonization frequency was 35.6% (n = 16/45) in patients (87.5% MSSA– 12.5% MRSA) and 43.1% (n = 53/123) in household contacts (88.7% MSSA—11.3% MRSA). Of 45 homes, 77.8% presented colonized people. Colonization was detected in at least two household members in 46.7% of homes, of which 52.4% had a genetic relationship. Colonization was 16% (n = 4/25) in pets (75% MRSA—25% MSSA). The most frequent clonal complex was CC8 (15.6%), and the spa typing revealed high diversity.

Conclusion

This study shows a high frequency of colonization by S. aureus in both hemodialysis patients and their household contacts and a significant genetic relationship between their isolates. This demonstrates an exchange of this bacterium and that homes are an important source of colonization to patients, highlighting the need for prevention strategies outside the hospital to avoid future infections, and the importance of the populations with permanent transit between the two environments.

Management and Prevention of Staphylococcus aureus Infections in Children

Staphylococcus aureus is a common skin commensal with the potential to cause severe infections resulting in significant morbidity and mortality. Up to 30% of individuals are colonized with S aureus, though infection typically does not occur without skin barrier disruption. Infection management includes promptly addressing the source of infection, including sites of metastatic infection, and initiation of effective antibiotics, which should be selected based on local antibiotic susceptibility patterns. Given that S aureus colonization is a risk factor for infection, preventive strategies are aimed at optimizing hygiene measures and decolonization regimens for outpatients and critically ill children with prolonged hospitalizations.

Biosynthetic Microcin J25 Exerts Strong Antibacterial, Anti-Inflammatory Activities, Low Cytotoxicity Without Increasing Drug-Resistance to Bacteria Target

Multidrug resistant (MDR) bacterial infection has emerged, raising concerns about untreatable infections, and posing the highest health risks. Antimicrobial peptides (AMPs) are thought to be the best remedy for this problem. Here, we showed biosynthetic microcin J25 (MccJ25) exhibited excellent bactericidal activity against standard and clinically relevant veterinary MDR strains with high stability, no cytotoxicity, and no increase in drug resistance. Analysis of antimicrobial mechanism possessed by sensitive enterotoxigenic Escherichia coli (ETEC) based on electron microscopy and Sytox Green methods was carried out. Results showed excellent activity against ETEC was due to permeabilizing bacterial membranes and strong affinity. MccJ25 exhibited high endotoxin-neutralizing activity in both in vivo and in vitro environments, and mice exposed to lipopolysaccharide (LPS) showed decreased plasma LPS levels and improved survival after administration of MccJ25. In an LPS-treated mouse septicemia model, MccJ25 treatment significantly alleviated inflammatory responses by inhibiting proinflammatory factor secretion and expression. In a mouse E. coli infection model, administration of MccJ25 effectively improved host defense against clinically source cocktail of multidrug-resistant E. coli strains induced intestinal inflammation and bacteria dissemination. Results of studies on anti-inflammatory mechanisms showed that MccJ25 downregulated nuclear factor kappa B kinase and mitogen-activated protein kinase, thereby reducing the production of toll-like receptor 4, myeloid differentiation factor 88 and decreasing the key proinflammatory cytokines. These findings clarify MccJ25 may be an ideal antibacterial/antiendotoxic drug candidate that has the potential to further guide the development of anti-inflammatory and/or antimicrobial agents in the war against MDR bacterial infection.

Efficacy of a quaternary ammonium compound in reducing coagulase-positive staphylococcal colony counts in veterinary dermatology exam rooms following two cleaning instruction protocols

BACKGROUND

Nosocomial meticillin-resistant (MR) staphylococcal infections are of global concern. Veterinary dermatology exam room surfaces may be a reservoir given the commonness of staphylococcal pyoderma.

HYPOTHESIS/OBJECTIVES

First, efficacy of exam room surface decontamination using a quaternary ammonium compound was assessed after use of two different cleaning instruction protocols. Second, coagulase-positive staphylococcal (CoPS) colony counts were assessed after use of rooms by dogs with pyoderma, and then after cleaning and disinfection.

METHODS AND MATERIALS

In Part I, 10 room surfaces were tagged with a discreet fluorescent dye, Glo Germ, to assess the efficacy of surface cleaning between two Virex II 256-based cleaning protocols. In Part II, CoPS colonies were quantified via 3M Staph Express System. Ten standardised room surfaces were sampled after use by a dog with staphylococcal pyoderma, and immediately after a detailed cleaning and disinfection protocol.

RESULTS

A total of 24 of 100 and 81 of 100 surfaces were completely cleaned by the general and detailed protocols, respectively. The mean number of surfaces adequately cleaned was higher with the detailed protocol (P = 0.003). The detailed protocol reduced CoPS colony counts of eight surfaces (P < 0.01), and not chairs (P = 0.055). No CoPS were isolated from the exam table under a table mat.

CONCLUSIONS AND CLINICAL RELEVANCE

Detailed exam room cleaning and disinfection protocols are recommended to minimise contamination of veterinary exam room surfaces with staphylococci. The appropriate disinfection of chairs necessitates further study.

Pathogen Control in the Built Environment: A Probiotic-Based System as a Remedy for the Spread of Antibiotic Resistance

The high and sometimes inappropriate use of disinfectants and antibiotics has led to alarming levels of Antimicrobial Resistance (AMR) and to high water and hearth pollution, which today represent major threats for public health. Furthermore, the current SARS-CoV-2 pandemic has deeply influenced our sanitization habits, imposing the massive use of chemical disinfectants potentially exacerbating both concerns. Moreover, super-sanitation can profoundly influence the environmental microbiome, potentially resulting counterproductive when trying to stably eliminate pathogens. Instead, environmentally friendly procedures based on microbiome balance principles, similar to what applied to living organisms, may be more effective, and probiotic-based eco-friendly sanitation has been consistently reported to provide stable reduction of both pathogens and AMR in treated-environments, compared to chemical disinfectants. Here, we summarize the results of the studies performed in healthcare settings, suggesting that such an approach may be applied successfully also to non-healthcare environments, including the domestic ones, based on its effectiveness, safety, and negligible environmental impact.

Genomic Investigation of Two Acinetobacter baumannii Outbreaks in a Veterinary Intensive Care Unit in The Netherlands

Acinetobacter baumannii is a nosocomial pathogen that frequently causes healthcare-acquired infections. The global spread of multidrug-resistant (MDR) strains with its ability to survive in the environment for extended periods imposes a pressing public health threat. Two MDR A. baumannii outbreaks occurred in 2012 and 2014 in a companion animal intensive care unit (caICU) in the Netherlands. Whole-genome sequencing (WGS) was performed on dog clinical isolates (n = 6), environmental isolates (n = 5), and human reference strains (n = 3) to investigate if the isolates of the two outbreaks were related. All clinical isolates shared identical resistance phenotypes displaying multidrug resistance. Multi-locus Sequence Typing (MLST) revealed that all clinical isolates belonged to sequence type ST2. The core genome MLST (cgMLST) results confirmed that the isolates of the two outbreaks were not related. Comparative genome analysis showed that the outbreak isolates contained different gene contents, including mobile genetic elements associated with antimicrobial resistance genes (ARGs). The time-measured phylogenetic reconstruction revealed that the outbreak isolates diverged approximately 30 years before 2014. Our study shows the importance of WGS analyses combined with molecular clock investigations to reduce transmission of MDR A. baumannii infections in companion animal clinics.

A Novel Polymeric Nanohybrid Antimicrobial Engineered by Antimicrobial Peptide MccJ25 and Chitosan Nanoparticles Exerts Strong Antibacterial and Anti-Inflammatory Activities

Infection caused by antibiotic-resistant microorganisms (ARMs) has been declared a global threat to public health. Polymeric nanoparticles (PNPs) formed by antimicrobial peptides (AMPs) and synthetic PNPs against ARM infections are emerging. PNPs are also considered to be a promising natural biological preservative that prevents microbial spoilage through food processing and preservation. We engineered CNMs, a novel nanocomposite antibacterial agent based on chitosan nanoparticles and AMP microcin J25. In this study, we aimed to evaluate the comprehensive antimicrobial activity, potential antimicrobial mechanism, and anti-inflammatory activity of CNMs. We demonstrated that CNMs harbor excellent bactericidal activity against clinical foodborne pathogens and ARMs. CNMs caused fast mortality against different growth phases of tetracycline (Tet)-resistant enterotoxigenic E. coli (ETEC) and significantly killed Tet-resistant ETEC in food biological environments. Mechanistically, CNMs have the ability to bind lipopolysaccharides (LPS), neutralize endotoxin, and promote diaphragm permeability by damaging the cell membrane. CNMs did not cause mouse RAW264.7 cell cytotoxicity. Notably, CNMs significantly reduced the cytotoxicity of RAW264.7 macrophages induced by LPS. The LPS-induced inflammatory response was significantly ameliorated by CNMs by reducing the levels of nitric oxide and proinflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-6, IL-8, IL-1β, Toll-like receptor 4, and nuclear factor κB (NF-κB), in LPS-challenged RAW264.7 macrophages. CNMs downregulated the NF-κB and mitogen-activated protein kinase signaling pathways, thereby inhibiting inflammatory responses upon LPS stimulation. Taken together, CNMs could be applied as effective antimicrobial/anti-inflammatory agents with lower cytotoxicity in food, medicine, and agriculture to prevent bacterial contamination and infection, respectively.

A Novel Nano-Antimicrobial Polymer Engineered with Chitosan Nanoparticles and Bioactive Peptides as Promising Food Biopreservative Effective against Foodborne Pathogen E. coli O157-Caused Epithelial Barrier Dysfunction and Inflammatory Responses

For food quality and safety issues, the emergence of foodborne pathogenic bacteria has further accelerated the spread of antibiotic residues and drug resistance genes. To alleviate the harm caused by bacterial infections, it is necessary to seek novel antimicrobial agents as biopreservatives to prevent microbial spoilage. Nanoantimicrobials have been widely used in the direct treatment of bacterial infections. CNMs, formed by chitosan nanoparticles and peptides, are promising antibiotic alternatives for use as excellent new antibacterial drugs against pathogenic bacteria. Herein, the current study evaluated the function of CNMs in the protection of foodborne pathogen Escherichia coli (E. coli) O157 infection using an intestinal epithelial cell model. Antibacterial activity assays indicated that CNMs exerted excellent bactericidal activity against E. coli O157. Assessment of the cytotoxicity risks toward cells demonstrated that 0.0125–0.02% of CNMs did not cause toxicity, but 0.4% of CNMs caused cytotoxicity. Additionally, CNMs did not induced genotoxicity either. CNMs protected against E. coli O157-induced barrier dysfunction by increasing transepithelial electrical resistance, decreasing lactate dehydrogenase and promoting the protein expression of occludin. CNMs were further found to ameliorate inflammation via modulation of tumor factor α, toll-like receptor 4 and nuclear factor κB (NF-κB) expression via inhibition of mitogen-activated protein kinase and NF-κB activation and improved antioxidant activity. Taken together, CNMs could protect the host against E. coli O157-induced intestinal barrier damage and inflammation, showing that CNMs have great advantages and potential application as novel antimicrobial polymers in the food industry as food biopreservatives, bringing new hope for the treatment of bacterial infections.

Biocide-tolerance and antibiotic-resistance in community environments and risk of direct transfers to humans: Unintended consequences of community-wide surface disinfecting during COVID-19?

During the current pandemic, chemical disinfectants are ubiquitously and routinely used in community environments, especially on common touch surfaces in public settings, as a means of controlling the virus spread. An underappreciated risk in current regulatory guidelines and scholarly discussions, however, is that the persisting input of chemical disinfectants can exacerbate the growth of biocide-tolerant and antibiotic-resistant bacteria on those surfaces and allow their direct transfers to humans. For COVID-19, the most commonly used disinfecting agents are quaternary ammonium compounds, hydrogen peroxide, sodium hypochlorite, and ethanol, which account for two-thirds of the active ingredients in current EPA-approved disinfectant products for the novel coronavirus. Tolerance to each of these compounds, which can be either intrinsic or acquired, has been observed on various bacterial pathogens. Of those, mutations and horizontal gene transfer, upregulation of efflux pumps, membrane alteration, and biofilm formation are the common mechanisms conferring biocide tolerance in bacteria. Further, the linkage between disinfectant use and antibiotic resistance was suggested in laboratory and real-life settings. Evidence showed that substantial bacterial transfers to hands could effectuate from short contacts with surrounding surfaces and further from fingers to lips. While current literature on disinfectant-induced antimicrobial resistance predominantly focuses on municipal wastes and the natural environments, in reality the community and public settings are most severely impacted by intensive and regular chemical disinfecting during COVID-19 and, due to their proximity to humans, biocide-tolerant and antibiotic-resistant bacteria emerged in these environments may pose risks of direct transfers to humans, particularly in densely populated urban communities. Here we highlight these risk factors by reviewing the most pertinent and up-to-date evidence, and provide several feasible strategies to mitigate these risks in the scenario of a prolonging pandemic.

Prevalence of methicillin-resistant Staphylococcus aureus in Iranian children: a systematic review and meta-analysis

BACKGROUND

Antibiotic resistance is associated with longer hospitalizations, higher treatment costs, and increased morbidity and mortality rates.

PURPOSE

This study aimed to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Iranian children.

METHODS

International databases, including Web of Science, PubMed, Embase, and Scopus, and Iranian databases, including Scientific Information Database (www.sid.ir), Magiran, and Iranian Database for Medical Literature (idml.research.ac.ir), were systematically searched for articles published between January 2000 and August 2019. Sources of heterogeneity were determined using subgroup analysis and meta-regression.

RESULTS

Overall, 343 studies were identified; of them, 20 were included in the meta-analysis to estimate the pooled prevalence. The pooled prevalence of MRSA was 42% (95% confidence interval [CI], 29-55) among culture-positive cases of S. aureus, 51% (95% CI, 39-62) in hospitalized children, and 14% (95% CI, 0.05-27) in healthy children.

CONCLUSION

The overall pooled prevalence of MRSA in children was 42%. Appropriate infection control measures and effective antibiotic therapy are needed.

Household Transmission of Community-Associated Methicillin-Resistant Staphylococcus Aureus

Currently, the mechanism of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) transmission mechanism is unclear; however, it must be considered in conjunction with asymptomatic S. aureus strains colonization dynamics. This epidemiological study aimed to determine the role of the household in CA-MRSA transmission in China. Five patients with culture-confirmed CA-MRSA infection and five control patients were recruited from the Sir Run Run Shaw Hospital in Zhejiang, China, between December 2019 and January 2020. The household members of the patients, their pets, and environmental surfaces were sampled and screened for MRSA colonization. Mass spectrometry identification and antimicrobial susceptibility testing were performed on the MRSA isolates. Whole-genome sequencing and core genome multilocus sequence typing (cgMLST) were performed to determine the origin and transmission of the MRSA isolates in the households. Overall, 14 S. aureus-positive specimens (14.1%, 14/99) were obtained from the five households of patients with CA-MRSA infections, of which 12 (85.7%) were MRSA. The overall positivity of MRSA was 12.1% (12/99) among the samples from the CA-MRSA households, while no MRSA isolates were detected in the five control households. Most MRSA isolates belonged to epidemic CA-MRSA clones, such as ST59 (15/35, 42.9%) and ST508 (15/35, 42.9%). The cgMLST results confirmed that MRSA was transmitted among patients, contacts, and pets in the households and was present on environmental surfaces in the CA-MRSA patients' households. In conclusion, the study revealed that the home environment was an important MRSA reservoir. Therefore, focusing on MRSA decolonization in patients alone is not sufficient for infection control of CA-MRSA.

RNA thermoswitches modulate Staphylococcus aureus adaptation to ambient temperatures

Thermoregulation of virulence genes in bacterial pathogens is essential for environment-to-host transition. However, the mechanisms governing cold adaptation when outside the host remain poorly understood. Here, we found that the production of cold shock proteins CspB and CspC from Staphylococcus aureus is controlled by two paralogous RNA thermoswitches. Through in silico prediction, enzymatic probing and site-directed mutagenesis, we demonstrated that cspB and cspC 5′UTRs adopt alternative RNA structures that shift from one another upon temperature shifts. The open (O) conformation that facilitates mRNA translation is favoured at ambient temperatures (22°C). Conversely, the alternative locked (L) conformation, where the ribosome binding site (RBS) is sequestered in a double-stranded RNA structure, is folded at host-related temperatures (37°C). These structural rearrangements depend on a long RNA hairpin found in the O conformation that sequesters the anti-RBS sequence. Notably, the remaining S. aureus CSP, CspA, may interact with a UUUGUUU motif located in the loop of this long hairpin and favour the folding of the L conformation. This folding represses CspB and CspC production at 37°C. Simultaneous deletion of the cspB/cspC genes or their RNA thermoswitches significantly decreases S. aureus growth rate at ambient temperatures, highlighting the importance of CspB/CspC thermoregulation when S. aureus transitions from the host to the environment.

Bacterial zoonoses transmitted by household pets and as reservoirs of antimicrobial resistant bacteria

Numerous individuals are committed to growing pet creatures like cats, dogs, and rats etc., pay care for them and as a result of this, there's a boost of their populace in advanced culture. The close interaction between family pets and individuals offers ideal conditions for bacterial transmission. Distinctive sorts of antimicrobial agents are exploited for animal husbandry and studies have revealed that many bacteria have attained confrontation against them viz., Staphylococcus intermedius, Escherichia coli, methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococci and multidrug-resistant Salmonella typhi etc. and a few of these are a prospective for zoonotic transmission. In the current review, the attention has been paid on how household pets, especially dogs disperse the antimicrobial resistance in contrast to that of food animals. A lot of evidences are accessible on food animals and nation-wide scrutiny programmes solely hub on food animals; therefore, for steerage antimicrobial use policy in small animal veterinary exercise as well as for gauging the chance of transmission of antimicrobial resistance to humans' statistics on pet animals are sincerely needed. Transmission of such organisms, especially pathogenic staphylococci, occurs between pets, owners, and veterinary staff, and pets can act as reservoirs of such bacteria; this may additionally have an impact on the use of antimicrobials in human medicine. There is a need to generate statistics concerning each the levels of carriage of such microorganism in pets and the risk factors associated with the switch of the microorganism to human beings who have contact with infected pets, as nicely as to improve hygiene measures in veterinary practice.

Data on before and after the Traceability System of Veterinary Antimicrobial Prescriptions in Small Animals at the University Veterinary Teaching Hospital of Naples

Simple Summary

Veterinary electronic prescription (VEP) is mandatory by law, dated 20 November 2017, No. 167 (European Law 2017) Article 3, and has been implemented in Italy since April 2019. In this study, the consumption of antimicrobials before and after the mandatory use of VEP was analyzed at the Italian University Veterinary Teaching Hospital of Naples in order to understand how the traceability of antimicrobials influences veterinary prescriptions. The applicability and utility of VEP may present an effective surveillance strategy able to limit both the improper use of antimicrobials and the spread of multidrug-resistant pathogens, which have become a worrying threat both in veterinary and human medicine.

Abstract

Over recent decades, antimicrobial resistance has been considered one of the most relevant issues of public health. The aim of our study was to evaluate the differences related to the prescription of antimicrobials at the University Veterinary Teaching Hospital, before and after the mandatory use of veterinary electronic prescription (VEP). In particular, the consumption of antimicrobials was examined, especially taking into consideration the recommendations of prudent use. A comparison of data collected before and after the use of electronic prescription highlighted that during the period chosen for the study, the choice of antimicrobial molecules was appropriate, favoring those of “first” and “second line.” However, prescription and the use of some molecules not registered for veterinary medicine were observed in the period before VEP. Broad-spectrum antimicrobials, including penicillins with β-lactamase inhibitors, as well as first-generation cephalosporins and fluoroquinolones, were the most frequently prescribed compounds. There are few studies conducted in Italy aimed at investigating the use of antimicrobials in companion animals under field conditions and with particular regard to prudent use recommendations. This type of study underlines the importance of electronic medical recording in veterinary practice and, above all, its usefulness in monitoring the use of certain antimicrobial agents classified as of critical importance in human medicine.

Evaluation of Methods for Sampling of Staphylococcus aureus and Other Staphylococcus Species from Indoor Surfaces

Objectives

Methicillin-resistant Staphylococcus aureus (MRSA) is an increasing public and occupational health concern. As transmission of MRSA can occur via contact with fomites, it is crucial to have sensitive methods for sampling of bacteria. The overall aim of this study was to obtain knowledge about methods and strategies for quantitative sampling Staphylococcus species on surfaces.

Methods

The study was designed as a comparative sampling experiment with different samplers [dipslide (two agar types), swabs (three brands, used wet and dry, and elution from swabs or plate diluted)] on smooth stainless steel surfaces spiked with MRSA and methicillin-sensitive S. aureus (MSSA). Furthermore, bacteria sampled from indoor surfaces with frequent or infrequent contact with hands were quantified and identified using matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS).

Results

Pre-moistened swabs in combination with dilution plating and dipslides were more sensitive than dry swabs. For recovery of MRSA and MSSA from surfaces with eSwabs, at least 0.3–100 CFU MRSA cm⁻² and 5.3–8.6 CFU MSSA cm⁻² should be present. The sensitivities of pre-moistened eSwabs were approximately 10-fold higher than those of dipslides and pre-moistened viscose and cotton swabs. The variation in concentrations of Staphylococcus species in replicate sampling of adjacent squares on indoor surfaces was higher for surfaces frequently touched by hands than for surfaces infrequently touched. In total 16 different Staphylococcus species were identified, and S. aureus was found only in 2 of 66 surface samples. A considerable overlap was found between species in replicate sampling within an environment and between the air and surfaces within an environment.

Conclusions

Pre-moistened eSwabs in combination with dilution plating were found to be the best method for surface sampling of MSSA and MRSA. The method can be used for assessing the risk of exposure and transmission of MRSA from environmental surfaces. To obtain a reliable measure of concentrations and the presence of Staphylococccus species a higher number of samples should be taken from surfaces with hand contact than from surfaces dominated by sedimented bacteria.

Risk of Foodborne Illness from Pet Food: Assessing Pet Owners' Knowledge, Behavior, and Risk Perception

Pet food has been identified as a source of pathogenic bacteria, including Salmonella and Escherichia coli. A recent outbreak linked to Salmonella -contaminated pet treats infected over 150 people in the United States. The mechanism by which contaminated pet food leads to human illness has not been explicated. Pet owners' food safety knowledge and their pet food handling practices have not been reported. This study evaluated pet owners' food safety knowledge and pet-food handling practices through an online consumer survey. The survey consists of 62 questions and assesses (1) owners' food safety knowledge and pet-food handling practices; (2) owners' interaction with pets; (3) owners' risk perception related to their own health, their children's health, and their pets' health. The survey was pilot-tested among 59 pet owners before distribution to a national consumer panel, managed by Qualtrics XM. All participants (n=1,040) were dog and/or cat owners in the United States. Almost all pet owners interacted with their pets (93%) and most cuddled, allowed their pets to lick them, and slept with their pets. Less than one-third of pet owners washed their hands with soap after interacting with their pets. Over half (58%) the owners reported washing their hands after feeding their pets. Most pet owners fed their pets dry pet food and dry pet treats. Some fed their pets raw meat or raw animal product (RAP) diets because they believed these diets to be beneficial to their pet's overall health. Many owners (78%) were unaware of pet food recalls or outbreaks associated with foodborne pathogens. Less than 25% considered dry pet foods and treats as a potential source of foodborne pathogens. The findings of this study indicated the need for consumer education about pet food handling. The data collected can assist in developing more accurate risk assessment models and consumer education related to pet food handling.

Influence of ventilation use and occupant behaviour on surface microorganisms in contemporary social housing

In the context of increasingly airtight homes, there is currently little known about the type and diversity of microorganisms in the home, or factors that could affect their abundance, diversity and nature. In this study, we examined the type and prevalence of cultivable microorganisms at eight different sites in 100 homes of older adults located in Glasgow, Scotland. The microbiological sampling was undertaken alongside a household survey that collated information on household demographics, occupant behaviour, building characteristics, antibiotic use and general health information. Each of the sampled sites revealed its own distinct microbiological character, in both species and number of cultivable microbes. While some potential human pathogens were identified, none were found to be multidrug resistant. We examined whether the variability in bacterial communities could be attributed to differences in building characteristics, occupant behaviour or household factors. Sampled sites furnished specific microbiological characteristics which reflected room function and touch frequency. We found that homes that reported opening windows more often were strongly associated with lower numbers of Gram-negative organisms at indoor sites (p < 0.0001). This work offers one of the first detailed analysis of cultivable microbes in homes of older adults and their relationship with building and occupancy related factors, in a UK context.

Staphylococcus aureus Population Structure and Genomic Profiles in Asymptomatic Carriers in Switzerland

Staphylococcus aureus is a leading cause for clinical infections and food intoxications, causing over 100,000 yearly cases of bacteremia in the United States and 434 food-borne outbreaks in the European Union. Approximately 30% of the population permanently carry S. aureus asymptomatically in their nasal cavity. The risk of infection and transmission to food items or the environment is higher in individuals that are nasally colonized. In addition, S. aureus can acquire various antimicrobial resistances leading to therapeutic failure, additional medical costs, and fatalities. Methicillin-resistant S. aureus (MRSA) cause a considerable burden of disease in humans and animals. MRSA carriage has been associated with animal and in particular livestock contact. Extensive current data on the virulence gene profiles, as well as data on antimicrobial resistance determinants is crucial in developing effective strategies to mitigate the burden of disease. To this end, we screened the anterior nares of 160 test subjects (87 pupils and 73 members of farmer families) in Switzerland for S. aureus carriage. A total of 73 S. aureus isolates were obtained. Factors such as exposure to farm or companion animals and personal medical history were recorded using a questionnaire. Using a DNA microarray, isolates were assigned to clonal complexes (CCs), and virulence and resistance gene profiles were determined. The collected strains were assigned to 20 CCs, among others CC1, CC7, CC8, CC15, CC30, CC45, CC97, and CC398. Two MRSA strains and one multiresistant isolate carrying genes blaZ/I/R, InuA, aadD, tetK, and fosB were isolated from farmers with intensive exposure to animals. Strains carrying pvl, causing severe skin lesions and necrotizing pneumonia, as well as tetracycline, erythromycin, and kanamycin resistance genes were found in individuals that had taken antibiotics during the last year. A variety of superantigenic toxin genes was detected, including among others, the toxic shock syndrome toxin (tst1), and various enterotoxins (sea, sec, sel, and the egc cluster). Contact to chickens was identified as a significant factor contributing to S. aureus colonization.

Efficacy of three disinfectant formulations and a hydrogen peroxide/silver fogging system on surfaces experimentally inoculated with meticillin-resistant Staphylococcus pseudintermedius

BACKGROUND

Effective environmental disinfection is necessary to prevent nosocomial infections from meticillin-resistant Staphylococcus pseudintermedius (MRSP). However, there are currently no commercial disinfectant sprays or fogging systems with label claims against MRSP.

HYPOTHESIS/OBJECTIVES

To evaluate the efficacy of a quaternary ammonium product (QAC), an accelerated hydrogen peroxide product (AHP), a hydrogen peroxide and silver product (HAL), and a hydrogen peroxide and silver fogging system (FOG) against MRSP.

METHODS AND MATERIALS

Sterile plastic surfaces inoculated with MRSP were treated with 200 µL of QAC, AHP or HAL for the recommended contact times. For FOG, inoculated samples were placed in eight positions within a sealed room before fogging for the recommended contact time. Post-treatment bacterial counts were compared to untreated positive controls. Sterile uninoculated surfaces served as negative controls.

RESULTS

Least-squares mean reduction (log₁₀ ) in colony forming units (cfu) was 3.55 log₁₀ for QAC (P < 0.0001), 3.60 log₁₀ for AHP (P < 0.0001), 1.66 log₁₀ for HAL (P < 0.0001) and 0.32 log₁₀ for FOG (P = 0.004). QAC, AHP and HAL reduced MRSP cfu by 99.97%, 99.98% and 97.81%, respectively. FOG reduced cfu by 52.14%.

CONCLUSIONS AND CLINICAL IMPORTANCE

QAC and AHP effectively disinfected surfaces inoculated with MRSP. Although HAL provided lower MRSP reduction, it may be considered clinically acceptable. FOG as a sole means of MRSP disinfection was not supported yet may have utility as an adjunctive disinfectant in clinical areas with bacterial densities lower than our experimental inoculum.

Evasion of host defenses by intracellular Staphylococcus aureus

Staphylococcus aureus is one of the leading causes of hospital and community-acquired infections worldwide. The increasing occurrence of antibiotic resistant strains and the high rates of recurrent staphylococcal infections have placed several treatment challenges on healthcare systems. In recent years, it has become evident that S. aureus is a facultative intracellular pathogen, able to invade and survive in a range of cell types. The ability to survive intracellularly provides this pathogen with yet another way to evade antibiotics and immune responses during infection. Intracellular S. aureus have been strongly linked to several recurrent infections, including severe bone infections and septicemias. S. aureus is armed with an array of virulence factors as well as an intricate network of regulators that enable it to survive, replicate and escape from a number of immune and nonimmune host cells. It is able to successfully manipulate host cell pathways and use it as a niche to multiply, disseminate, as well as persist during an infection. This bacterium is also known to adapt to the intracellular environment by forming small colony variants, which are metabolically inactive. In this review we will discuss the clinical evidence, the molecular pathways involved in S. aureus intracellular persistence, and new treatment strategies for targeting intracellular S. aureus.

Outpatient decolonization after recurrent skin infection with Panton-Valentine leukocidin (PVL)-producing S. aureus-The importance of treatment repetition

BACKGROUND

Recurrent skin abscesses are often associated with Panton-Valentine leukocidin-producing strains of S. aureus (PVL-SA). Decolonization measures are required along with treatment of active infections to prevent re-infection and spreading. Even though most PVL-SA patients are treated as outpatients, there are few studies that assess the effectiveness of outpatient topical decolonization in PVL-SA patients.

METHODS

We assessed the results of topical decolonization of PVL-SA in a retrospective review of patient files and personal interviews. Successful decolonization was defined as the absence of any skin abscesses for at least 6 months after completion of the final decolonization treatment. Clinical and demographic data was assessed. An intention-to-treat protocol was used.

RESULTS

Our cohort consisted of 115 symptomatic patients, 66% from PVL-positive MSSA and 19% from PVL-positive MRSA. The remaining 16% consisted of symptomatic patients with close contact to PVL-SA positive index patients but without detection of PVL-SA. The majority of patients were female (66%). The median age was 29.87% of the patients lived in multiple person households. Our results showed a 48% reduction in symptomatic PVL-SA cases after the first decolonization treatment. The results also showed that the decrease continued with each repeated decolonization treatment and reached 89% following the 5th treatment. A built multivariable Cox proportional-hazards model showed that the absence of PVL-SA detection (OR 2.0) and living in single person households (OR 2.4) were associated with an independently increased chance of successful decolonization.

CONCLUSION

In our cohort, topical decolonization was a successful preventive measure for reducing the risk of PVL-SA skin abscesses in the outpatient setting. Special attention should be given to patients living in multiple person households because these settings could confer a risk that decolonization will not be successful.

Antimicrobial Resistance in Veterinary Medicine: An Overview

Antimicrobial resistance (AMR) represents one of the most important human- and animal health-threatening issues worldwide. Bacterial capability to face antimicrobial compounds is an ancient feature, enabling bacterial survival over time and the dynamic surrounding. Moreover, bacteria make use of their evolutionary machinery to adapt to the selective pressure exerted by antibiotic treatments, resulting in reduced efficacy of the therapeutic intervention against human and animal infections. The mechanisms responsible for both innate and acquired AMR are thoroughly investigated. Commonly, AMR traits are included in mobilizable genetic elements enabling the homogeneous diffusion of the AMR traits pool between the ecosystems of diverse sectors, such as human medicine, veterinary medicine, and the environment. Thus, a coordinated multisectoral approach, such as One-Health, provides a detailed comprehensive picture of the AMR onset and diffusion. Following a general revision of the molecular mechanisms responsible for both innate and acquired AMR, the present manuscript focuses on reviewing the contribution of veterinary medicine to the overall issue of AMR. The main sources of AMR amenable to veterinary medicine are described, driving the attention towards the indissoluble cross-talk existing between the diverse ecosystems and sectors and their cumulative cooperation to this warning phenomenon.

Antimicrobial Usage and Resistance in Companion Animals: A Cross-Sectional Study in Three European Countries

Companion animals have been described as potential reservoirs of antimicrobial resistance (AMR), however data remain scarce. Therefore, the objectives were to describe antimicrobial usage (AMU) in dogs and cats in three European countries (Belgium, Italy, and The Netherlands) and to investigate phenotypic AMR. A questionnaire and one fecal sample per animal (n = 303) were collected over one year and AMU was quantified using treatment incidence (TI). Phenotypic resistance profiles of 282 Escherichia coli isolates were determined. Nineteen percent of the animals received at least one antimicrobial treatment six months preceding sampling. On average, cats and dogs were treated with a standard daily dose of antimicrobials for 1.8 and 3.3 days over one year, respectively. The most frequently used antimicrobial was amoxicillin-clavulanate (27%). Broad-spectrum antimicrobials and critically important antimicrobials for human medicine represented 83% and 71% of the total number of treatments, respectively. Resistance of E. coli to at least one antimicrobial agent was found in 27% of the isolates. The most common resistance was to ampicillin (18%). Thirteen percent was identified as multidrug resistant isolates. No association between AMU and AMR was found in the investigated samples. The issue to address, regarding AMU in companion animal, lies within the quality of use, not the quantity. Especially from a One-Health perspective, companion animals might be a source of transmission of resistance genes and/or resistant bacteria to humans.

Airborne Staphylococcus aureus in different environments-a review

The aim of the literature review was to describe the environments where the presence of airborne Staphylococcus aureus was confirmed and to catalogue the most often used methods and conditions of bioaerosol sampling to identify the bacteria. The basis for searching of studies on S. aureus in the bioaerosol in different environments was PubMed database resources from the years 1990-2019 (May). The review included studies which were carried on in selected environments: hospitals and other health care facilities, large-scale animal breeding, wastewater treatment plants, residential areas, educational institutions, and other public places. The highest concentrations and genetic diversity of identified S. aureus strains, including MRSA (methicillin-resistant S. aureus), have been shown in large-scale animal breeding. The role of the airborne transmission in dissemination of infection caused by these pathogens is empirically confirmed in environmental studies. Commonly available, well-described, and relatively inexpensive methods of sampling, identification, and subtyping guarantee a high reliability of results and allow to obtain fast and verifiable outcomes in environmental studies on air transmission routes of S. aureus strains.

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.

Organic dust exposure in veterinary clinics: a case study of a small-animal practice in Portugal

Literature about occupational health in small-animal veterinary practices is scarce, but most of it has recognised a number of risks to be considered, including organic dust exposure. The aim of this pilot study was to assess organic dust, bacterial, and fungal contamination in the indoor environment of a typical Portuguese veterinary clinic but also to screen for azoleresistant fungi. To complement these findings we also analysed workers' nasal exudates for resistant bacteriota. Particles measurements included mass concentrations (PMC) of five particle sizes (PM0.5, PM1, PM2.5, PM5, PM10) and their counts (PNC). Indoor air samples were obtained from six locations as well as before and during cat dental cleaning and cultured on four media for bacterial and fungal assessment. An outdoor sample was also collected for reference Surface samples were taken from the same indoor locations using swabs and we also use electrostatic dust cloths as passive methods. PM10 showed the highest concentrations across the locations. Indoor air fungal loads ranged from 88 to 504 CFU m-3. The azole-resistant Aspergillus section Nigri was identified in one sample. Indoor air bacterial loads ranged from 84 to 328 CFU m-3. Nasopharyngeal findings in the 14 veterinary clinic workers showed a remarkably low prevalence of Staphylococcus aureus (7.1 %). Our results point to contamination with organic dusts above the WHO limits and to the need for better ventilation. Future studies should combine the same sampling protocol (active and passive methods) with molecular tools to obtain more accurate risk characterisation. In terms of prevention, animals should be caged in rooms separate from where procedures take place, and worker protection should be observed at all times.

Differences in gram-positive bacterial colonization and antimicrobial resistance among children in a high income inequality setting

Background

Staphylococcus aureus and beta-hemolytic streptococci (BHS) diseases disproportionately affect populations in middle/low-income countries. To assess if this disparity is reflected in colonization by these organisms, we compared their colonization frequency among children from different socioeconomic status (SES) communities in a city with high income inequality.

Methods

Between May–August 2014, we collected nasal and throat swabs to investigate S. aureus and BHS colonization among children who attended private and public pediatric clinics. Patients were classified as high SES, middle/low SES, and slum residents. We investigated the antimicrobial resistance profile, the SCCmec types and the presence of PVL genes among methicillin-resistant S. aureus (MRSA). We also examined the antimicrobial resistance profile and serogroups of BHS.

Results

Of 598 children, 221 (37%) were colonized with S. aureus, of which 49 (22%) were MRSA. MRSA colonization was higher in middle/low SES (n = 18; 14%) compared with high SES (n = 17; 6%) and slum (n = 14; 8%) residents (p = 0.01). All MRSA strains were susceptible to clindamycin, nitrofurantoin, and rifampin. The highest non-susceptibility frequency (42.9%) was observed to erythromycin. SCCmec type V was only found in isolates from high SES children; types I and II were found only in middle/low SES children. Ten (20%) MRSA isolates carried PVL genes. Twenty-four (4%) children were BHS carriers. All BHS (n = 8) found in high SES children and six (67%) isolates from slum patients belonged to group A. All group B streptococci were from middle/low SES children, corresponding to five (71%) of the seven BHS isolated in this group. BHS isolates were susceptible to all drugs tested.

Conclusions

Children from different SES communities had distinct bacterial colonization profiles, including MRSA carriage. Public health officials/researchers should consider SES when assessing disease transmission and control measures.

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.

Prevalence and Molecular Characterization of Staphylococcus aureus and Methicillin-resistant S. aureus on Children's Playgrounds

BACKGROUND

Staphylococcus aureus is a major public health concern due to the emergence of virulent and drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA). Although numerous studies have been conducted to assess the environmental contamination of S. aureus in health care and household settings, little is known about the prevalence and epidemiology of S. aureus, including MRSA, on environmental surfaces of children's playgrounds. This study investigated the prevalence and molecular epidemiology of S. aureus and MRSA at playgrounds in northeast Ohio.

METHODS

A total of 280 environmental samples were collected from 10 playgrounds in northeast Ohio in July 2016. Sampling sites were selected based on playground size and availability of equipment located in both small and large cities and their suburbs. Samples were analyzed using established microbiology methods, and resulting S. aureus isolates were typed by spa typing. Polymerase chain reaction was used to detect the presence of the Panton-Valentine leukocidin and mec A genes. Antibiotic susceptibility was tested via the Vitek-2 System.

RESULTS

The overall prevalence of S. aureus and MRSA was 31.8% (89/280) and 3.9% (11/280), respectively. A total of 43 spa types were detected from 257 S. aureus isolates. Overall, t189 was the most common spa type, accounting for 15.6% (40/257) of the isolates. Sixteen isolates (6.2%) were t002 (ST5/USA100), a common hospital-associated strain, and 11 isolates (4.3%) were t008 (ST8/USA300), a common community-associated strain. Five livestock-associated strain (t571/ST398) were also identified. Twenty-nine (11.3%) isolates were resistant to oxacillin, and 66 (25.7%) were multi-drug resistant S. aureus.

CONCLUSIONS

The results of this study indicate that environmental surfaces of playgrounds in northeastern Ohio were contaminated with S. aureus and MRSA. These data reinforce the need for implementing effective prevention strategies to mitigate the risk imposed to children by environmental contamination of MRSA.

Microbial Exchange via Fomites and Implications for Human Health

PURPOSE OF REVIEW

Fomites are inanimate objects that become colonized with microbes and serve as potential intermediaries for transmission to/from humans. This review summarizes recent literature on fomite contamination and microbial survival in the built environment, transmission between fomites and humans, and implications for human health.

RECENT FINDINGS

Applications of molecular sequencing techniques to analyze microbial samples have increased our understanding of the microbial diversity that exists in the built environment. This growing body of research has established that microbial communities on surfaces include substantial diversity, with considerable dynamics. While many microbial taxa likely die or lay dormant, some organisms survive, including those that are potentially beneficial, benign, or pathogenic. Surface characteristics also influence microbial survival and rates of transfer to and from humans. Recent research has combined experimental data, mechanistic modeling, and epidemiological approaches to shed light on the likely contributors to microbial exchange between fomites and humans and their contributions to adverse (and even potentially beneficial) human health outcomes.

SUMMARY

In addition to concerns for fomite transmission of potential pathogens, new analytical tools have uncovered other microbial matters that can be transmitted indirectly via fomites, including entire microbial communities and antibiotic-resistant bacteria. Mathematical models and epidemiological approaches can provide insight on human health implications. However, both are subject to limitations associated with study design, and there is a need to better understand appropriate input model parameters. Fomites remain an important mechanism of transmission of many microbes, along with direct contact and short- and long-range aerosols.

Interplay of personal, pet, and environmental colonization in households affected by community-associated methicillin-resistant Staphylococcus aureus

OBJECTIVE

We sought to determine the prevalence, molecular epidemiology, and factors associated with Staphylococcus aureus environmental surface and pet colonization in households of children with community-associated methicillin-resistant S. aureus (CA-MRSA) infection.

METHODS

Between 2012 and 2015, 150 children with CA-MRSA infections and their household contacts and pets were enrolled in this cross-sectional study in metropolitan Saint Louis, MO. Cultures to detect S. aureus were collected from 3 anatomic sites of household members, 2 dog/cat sites, and 21 environmental surfaces in each household. Molecular epidemiology of S. aureus isolates was determined via repetitive-sequence PCR. Generalized linear models were developed to identify factors associated with S. aureus/MRSA household contamination.

RESULTS

MRSA was recovered from environmental surfaces in 69 (46%) households (median 2 surfaces [range 1-18]). The enrollment infecting strain type was the most common strain recovered from the environment in most (64%) households. In generalized linear models, factors associated with a higher proportion of MRSA-contaminated environmental surfaces were household member MRSA colonization burden, MRSA as the dominant S. aureus strain colonizing household members, more strain types per household member, index case African-American race, and renting (vs. owning) the home. Of 132 pets, 14% were colonized with MRSA. Pets whose primary caretaker was MRSA-colonized were more likely to be MRSA-colonized than pets whose primary caretaker was not MRSA-colonized (50% vs. 4%, p < 0.001).

CONCLUSIONS

Household environments and pet dogs and cats serve as reservoirs of MRSA. Household member MRSA colonization burden predicts environmental MRSA contamination. Longitudinal studies will inform the directionality of household transmission.

Surface touch and its network growth in a graduate student office

Fomites transmit infection. A key question is how surface contamination in a building is spread by human touch. Using video cameras, we collected more than 120 000 touch actions from 60 hours of high-resolution data on surface touch across five typical weekdays in a graduate student office. The students touched surfaces with one or both hands during 94.6% of the observed period. On average, each student made five touches per minute, with an average duration of 22 seconds per touch. High-touch and high-risk surfaces and people were identified. 98.8% of the surfaces touched, such as mobile phones and human faces, were private, but public surfaces, such as a water dispenser button, were touched by 68% of the students in the office on average. Compared with females, males spent 3% more time touching surfaces. Right hands always had higher touch frequency than left hands. The surface network in the office was scale-free, whereas the hand network was small-world. The results revealed power law and logistic growth in the number of contaminated surfaces which suggests that fomite transmission can be extremely effective. The time taken for most surfaces to be contaminated after one surface became contaminated was much shorter for public than for private surfaces.