Assessment of the Public Health significance of meticillin resistant Staphylococcus aureus (MRSA) in animals and foods

Horse Meat Microbiota: Determination of Biofilm Formation and Antibiotic Resistance of Isolated Staphylococcus Spp

Domestic horses could be bred for leisure activities and meat production, as is already the case in many countries. Horse meat is consumed in various countries, including Kazakhstan and Kyrgyzstan, and with the increase in this consumption, horses are registered as livestock by the Food and Agricultural Organization. In this study, horse meat microbiota of horse samples (n = 56; 32 samples from Kazakhstan and 24 samples from Kyrgyzstan) from two countries, Kazakhstan (n = 3) and Kyrgyzstan (n = 1), were investigated for the first time by next-generation sequencing and metabarcoding analysis. The results demonstrated that Firmicutes, Proteobacteria, and Actinobacteria were the dominant bacterial phyla in all samples. In addition, three (5.4%) Staphylococcus strains were isolated from the Uzynagash region, Kazakhstan. Staphylococcus strains were identified as Staphylococcus warneri, S. epidermidis, and S. pasteuri by partial 16S rRNA DNA gene Sanger sequencing. All three Staphylococcus isolates were nonbiofilm formers; only the S. pasteuri was detected as multidrug-resistant (resistant to penicillin, cefoxitin, and oxacillin). In addition, S. pasteuri was found to carry mecA, mecC, and tetK genes. This is the first study to detect potentially pathogenic Staphylococcus spp. in horse meat samples originating from Kazakhstan. In conclusion, it should be carefully considered that undercooked horse meat may pose a risk to consumers in terms of pathogens such as antibiotic-resistant Staphylococcus isolates.

The European Union summary report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2021-2022

This report by the European Food Safety Authority and the European Centre for Disease prevention and Control, provides an overview of the main findings of the 2021-2022 harmonised Antimicrobial Resistance (AMR) monitoring in Salmonella spp., Campylobacter jejuni and C. coli from humans and food-producing animals (broilers, laying hens and fattening turkeys, fattening pigs and cattle under one year of age) and relevant meat thereof. For animals and meat thereof, AMR data on indicator commensal Escherichia coli, presumptive extended-spectrum beta-lactamases (ESBL)-/AmpC beta-lactamases (AmpC)-/carbapenemase (CP)-producing E. coli, and the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) are also analysed. Generally, resistance levels differed greatly between reporting countries and antimicrobials. Resistance to commonly used antimicrobials was frequently found in Salmonella and Campylobacter isolates from humans and animals. In humans, increasing trends in resistance to one of two critically antimicrobials (CIA) for treatment was observed in poultry-associated Salmonella serovars and Campylobacter, in at least half of the reporting countries. Combined resistance to CIA was however observed at low levels except in some Salmonella serovars and in C. coli from humans and animals in some countries. While CP-producing Salmonella isolates were not detected in animals in 2021-2022, nor in 2021 for human cases, in 2022 five human cases of CP-producing Salmonella were reported (four harbouring bla OXA-48 or bla OXA-48-like genes). The reporting of a number of CP-producing E. coli isolates (harbouring bla OXA-48, bla OXA-181, bla NDM-5 and bla VIM-1 genes) in fattening pigs, cattle under 1 year of age, poultry and meat thereof by a limited number of MSs (5) in 2021 and 2022, requires a thorough follow-up. The temporal trend analyses in both key outcome indicators (rate of complete susceptibility and prevalence of ESBL-/AmpC-producers in E. coli) showed an encouraging progress in reducing AMR in food-producing animals in several EU MSs over the last 7 years.

Whole-Genome Investigation of Zoonotic Transmission of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 398 Isolated from Pigs and Humans in Thailand

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been widespread globally in pigs and humans for decades. Nasal colonization of LA-MRSA is regarded as an occupational hazard to people who are regularly involved in livestock production. Our previous study suggested pig-to-human transmission caused by LA-MRSA clonal complex (CC) 398, using traditional molecular typing methods. Instead, this study aimed to investigate the zoonotic transmission of LA-MRSA CC398 using whole genome sequencing (WGS) technologies. A total of 63 LA-MRSA isolates were identified and characterized in Thailand. Further, the 16 representatives of LA-MRSA CC9 and CC398, including porcine and worker isolates, were subjected to WGS on the Illumina Miseq platform. Core-genome single nucleotide polymorphism (SNP)-based analyses verify the zoonotic transmission caused by LA-MRSA CC398 in two farms. WGS-based characterization suggests the emergence of a novel staphylococcal cassette chromosome (SCC) mec type, consisting of multiple cassette chromosome recombinase (ccr) gene complexes via genetic recombination. Additionally, the WGS analyses revealed putative multi-resistant plasmids and several cross-resistance genes, conferring resistance against drugs of last resort used in humans such as quinupristin/dalfopristin and linezolid. Significantly, LA-MRSA isolates, in this study, harbored multiple virulence genes that may become a serious threat to an immunosuppressive population, particularly for persons who are in close contact with LA-MRSA carriers.

Staphylococcus aureus in the Processing Environment of Cured Meat Products

The presence of Staphylococcus aureus in six dry-cured meat-processing facilities was investigated. S. aureus was detected in 3.8% of surfaces from five facilities. The occurrence was clearly higher during processing (4.8%) than after cleaning and disinfection (1.4%). Thirty-eight isolates were typified by PFGE and MLST. Eleven sequence types (STs) were defined by MLST. ST30 (32%) and ST12 (24%) were the most abundant. Enterotoxin genes were detected in 53% of isolates. The enterotoxin A gene (sea) was present in all ST30 isolates, seb in one ST1 isolate, and sec in two ST45 isolates. Sixteen isolates harbored the enterotoxin gene cluster (egc) with four variations in the sequence. The toxic shock syndrome toxin gene (tst) was detected in 82% of isolates. Regarding antimicrobial resistance, twelve strains were susceptible to all the antibiotics tested (31.6%). However, 15.8% were resistant to three or more antimicrobials and, therefore, multidrug-resistant. Our results showed that in general, efficient cleaning and disinfection procedures were applied. Nonetheless, the presence of S. aureus with virulence determinants and resistance to antimicrobials, particularly multidrug-resistant MRSA ST398 strains, might represent a potential health hazard for consumers.

MRSA in bulk tank milk of dairy herds in Germany - changes over time

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) have repeatedly been isolated from dairy herds. It was the purpose of this study to compare the results of 3 subsequent national scale cross-sectional investigations in dairy herds in Germany on the prevalence of MRSA in bulk tank milk and the characteristics of the isolates.

MATERIAL AND METHODS

The investigations were carried out in 2010, 2014 and 2019, respectively. MRSA were isolated from 25 ml of bulk tank milk using a double selective enrichment protocol. Samples were distributed across the country according to the regional dairy cattle population.

RESULTS

The prevalence of MRSA in bulk tank milk samples was lower in 2010 than in 2014 and tended to decrease until 2019. Prevalence was higher in samples from conventional than from organic herds and increased with herd size. Most isolates (75/78) were assigned to the clonal complex 398 and the spa-types t011 and t034. Resistance of the isolates to other antimicrobials than beta-lactams decreased over time.

CONCLUSIONS

MRSA remain present in the German dairy population and are found more frequently in larger vs. smaller herds and in conventional vs. organic herds.

CLINICAL RELEVANCE

MRSA should be considered in biosecurity protocols and with respect to occupational health of farm staff. Presence of MRSA in raw milk supports the recommendation not to drink unpasteurized raw milk.

The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2020/2021

Antimicrobial resistance (AMR) data on zoonotic and indicator bacteria from humans, animals and food are collected annually by the EU Member States (MSs) and reporting countries, jointly analysed by EFSA and ECDC and presented in a yearly EU Summary Report. This report provides an overview of the main findings of the 2020-2021 harmonised AMR monitoring in Salmonella spp., Campylobacter jejuni and C. coli in humans and food-producing animals (broilers, laying hens and turkeys, fattening pigs and bovines under 1 year of age) and relevant meat thereof. For animals and meat thereof, indicator E. coli data on the occurrence of AMR and presumptive Extended spectrum β-lactamases (ESBL)-/AmpC β-lactamases (AmpC)-/carbapenemases (CP)-producers, as well as the occurrence of methicillin-resistant Staphylococcus aureus are also analysed. In 2021, MSs submitted for the first time AMR data on E. coli isolates from meat sampled at border control posts. Where available, monitoring data from humans, food-producing animals and meat thereof were combined and compared at the EU level, with emphasis on multidrug resistance, complete susceptibility and combined resistance patterns to selected and critically important antimicrobials, as well as Salmonella and E. coli isolates exhibiting ESBL-/AmpC-/carbapenemase phenotypes. Resistance was frequently found to commonly used antimicrobials in Salmonella spp. and Campylobacter isolates from humans and animals. Combined resistance to critically important antimicrobials was mainly observed at low levels except in some Salmonella serotypes and in C. coli in some countries. The reporting of a number of CP-producing E. coli isolates (harbouring bla OXA-48, bla OXA-181, and bla NDM-5 genes) in pigs, bovines and meat thereof by a limited number of MSs (4) in 2021, requests a thorough follow-up. The temporal trend analyses in both key outcome indicators (rate of complete susceptibility and prevalence of ESBL-/AmpC- producers) showed that encouraging progress have been registered in reducing AMR in food-producing animals in several EU MSs over the last years.

Prevalence, Infectious Characteristics and Genetic Diversity of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus (MRSA) in Two Raw-Meat Processing Establishments in Northern Greece

In the present study, we investigated the isolation frequency, the genetic diversity, and the infectious characteristics of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from the incoming meat and the meat products, the environment, and the workers' nasal cavities, in two meat-processing establishments in northern Greece. The isolated S. aureus strains were examined for their resistance to antimicrobials, carriage of the mecA and mecC genes, carriage of genes encoding for the production of nine staphylococcal enterotoxins, carriage of the Panton-Valentine Leukocidin and Toxic Shock Syndrome genes, and the ability to form biofilm. The genetic diversity of the isolates was evaluated using Pulsed Field Gel Electrophoresis (PFGE) and spa typing. S. aureus was isolated from 13.8% of the 160 samples examined, while only one sample (0.6%) was contaminated by MRSA carrying the mecA gene. The evaluation of the antimicrobial susceptibility of the isolates revealed low antimicrobial resistance. The higher resistance frequencies were observed for penicillin (68.2%), amoxicillin/clavulanic acid (36.4%) and tetracycline (18.2%), while 31.8% of the isolates were sensitive to all antimicrobials examined. Multidrug resistance was observed in two isolates. None of the isolates carried the mecC or lukF-PV genes, and two isolates (9.1%) harbored the tst gene. Eight isolates (36.4%) carried the seb gene, one carried the sed gene, two (9.1%) carried both the sed and sei genes, and one isolate (4.5%) carried the seb, sed and sei genes. Twenty-one (95.5%) of the isolates showed moderate biofilm production ability, while only one (4.5%) was characterized as a strong biofilm producer. Genotyping of the isolates by PFGE indicates that S. aureus from different meat-processing establishments represent separate genetic populations. Ten different spa types were identified, while no common spa type isolates were detected within the two plants. Overall, our findings emphasize the need for the strict application of good hygienic practices at the plant level to control the spread of S. aureus and MRSA to the community through the end products.

Prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus isolates from retail raw meats in Turkey

The transmission of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) through food products of animal origin may pose a public health concern. Therefore, the objectives of the present work were to determine the prevalence of S. aureus and MRSA in raw meat samples (beef, chicken, turkey, and duck) at retail level, and to determine the antimicrobial resistance profile of the MRSA isolates. Between September 2018 and January 2019, a total of 325 raw meat samples were collected from retail stores, and analysed for the presence of S. aureus and MRSA using primary enrichment method as well as using secondary selective enrichment methods for MRSA detection. All the suspected S. aureus and MRSA colonies obtained from the samples were confirmed by both phenotypic and genotypic methods. The MRSA isolates were tested against various antimicrobials, and the minimal inhibitory concentration (MIC) of vancomycin was determined. Macrolide-lincosamide-streptogramin B (MLSB) resistance phenotypes were also screened using the double-disk diffusion test. The overall prevalence of S. aureus was 57.2%, whereas the food-specific prevalence in beef, turkey, duck, and chicken samples was 75, 53, 48, and 46%, respectively. The overall prevalence of MRSA was 1.2%, whereas it was 3, 1, 0, and 0% in beef, turkey, chicken, and duck samples, respectively. All MRSA isolates were detected by the secondary selective enrichment method. These MRSA isolates had a variety of MLSB resistance phenotypes (i.e., iMLSB, cMLSB, and MS-MLSB) with vancomycin MIC values ranging between 1 - 2 µg/mL. These findings are important for developing interventions to reduce raw meat contamination with S. aureus and MRSA, and to improve public health.

Role of milk and milk products in the spread of methicillin-resistant Staphylococcus aureus in the dairy production chain

Milk and milk products can harbor a multiple varieties of microorganisms. Therefore, they can be an important source of foodborne pathogens, including multidrug-resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) causes a wide spectrum of infections both in animals and humans. Over the last two decades, the presence of MRSA in foods and food-producing animals, including milk and milk products, has been frequently reported worldwide, raising public health concerns. In order to monitor and prevent foodborne MRSA contamination, it is necessary to understand their sources, the pheno/genotypic characteristics of the strains, and their transmission dynamics. In this review, studies conducted worldwide were summarized in order to assess the prevalence and diversity of MRSA circulating in milk and milk products. The risk factors for the occurrence of MRSA in milk and milk products were also discussed with preventive and control measures to avoid MRSA contamination in the dairy food chain.

The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2019-2020

Data on antimicrobial resistance (AMR) in zoonotic and indicator bacteria from humans, animals and food are collected annually by the EU Member States (MSs), jointly analysed by the EFSA and the ECDC and reported in a yearly EU Summary Report. The annual monitoring of AMR in animals and food within the EU is targeted at selected animal species corresponding to the reporting year. The 2020 monitoring specifically focussed on poultry and their derived carcases/meat, while the monitoring performed in 2019 specifically focused on fattening pigs and calves under 1 year of age, as well as their derived carcases/meat. Monitoring and reporting of AMR in 2019-2020 included data regarding Salmonella, Campylobacter and indicator E. coli isolates, as well as data obtained from the specific monitoring of presumptive ESBL-/AmpC-/carbapenemase-producing E. coli isolates. Additionally, some MSs reported voluntary data on the occurrence of methicillin-resistant Staphylococcus aureus in animals and food, with some countries also providing data on antimicrobial susceptibility. This report provides an overview of the main findings of the 2019-2020 harmonised AMR monitoring in the main food-producing animal populations monitored, in carcase/meat samples and in humans. Where available, monitoring data obtained from pigs, calves, broilers, laying hens and turkeys, as well as from carcase/meat samples and humans were combined and compared at the EU level, with particular emphasis on multidrug resistance, complete susceptibility and combined resistance patterns to critically important antimicrobials, as well as Salmonella and E. coli isolates possessing ESBL-/AmpC-/carbapenemase phenotypes. The key outcome indicators for AMR in food-producing animals, such as complete susceptibility to the harmonised panel of antimicrobials in E. coli and the prevalence of ESBL-/AmpC-producing E. coli have been specifically analysed over the period 2014-2020.

Staphylococcus aureus in poultry, with special emphasis on methicillin-resistant strain infection: A comprehensive review from one health perspective

Staphylococcus aureus is a Gram-positive coccus normally present on the skin and internal organs of animals, birds, and humans. Under certain conditions, S. aureus could produce septicemia and affection of the skin, joints, and heart, as well as sepsis and death. The pathogenicity of S. aureus is associated with the presence of some virulent surface proteins and the production of some virulent toxins and enzymes. This pathogen is considered one of the most important and worldwide foodborne causes as it is incriminated in most cases of food poisoning. The hazardous use of antibiotics in the veterinary field leads to the development of multidrug-resistant S. aureus strains that can be transmitted to humans. The incidence of methicillin-resistant S. aureus (MRSA) strains has increased globally. These resistant strains have been detected in live animals, poultry, and humans. In addition, retail animal products, especially those of avian origin, are considered the main source of MRSA strains that can be easily transmitted to humans. MRSA infection is regarded as nosocomial or occupational. Humans get infected with MRSA strains through improper handling or preparation of contaminated animals or poultry carcasses or improper cooking with contaminated meat. Live birds also can transmit MRSA to close-contact workers in poultry farms. Transmission of MRSA infection in hospitals is from an infected individual to a healthy one. Prevention and control of MRSA are based on the application of hygienic measures in farms as well as proper processing, handling, and cooking of retail poultry products. The cooperation between veterinary and human practitioners is a must to avoid the possibility of zoonotic transmission. Accordingly, this review focused on the sources and transmission of MRSA infection, virulence and resistance factors, incidence and prevalence in poultry and different products, antibiotic resistance, and prevention and control strategies.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) prevalence in humans in close contact with animals and measures to reduce on-farm colonisation

Since the 1940s, Staphylococcus aureus has adapted to the use of different antimicrobials to treat infections. Although S. aureus can act as a commensal bacterium, some strains are facultative pathogens and acquiring them can be fatal. In particular, treating infections caused by S. aureus with acquired antimicrobial resistance is problematic, as their treatment is more difficult. Some of these S. aureus variants are methicillin-resistant S. aureus (MRSA) with prevalence across the globe in health-care facilities, community settings and on livestock farms. Apart from humans, MRSA can colonise other animal species, and because of this, resistance to new antimicrobials can appear and jump between species. Livestock and companion animals are particularly important in this regard considering the relatively high usage of antimicrobials in these species. There is a risk to humans who come into direct contact with animals acquiring MRSA but there is also the risk of animals acquiring MRSA from colonised humans. In this review, we summarise studies conducted worldwide to characterise the prevalence of MRSA in veterinarians, farmers and other personnel who come into close contact with animals. Finally, alternative treatment, preventive measures and on-farm strategies to reduce MRSA introduction to a farm and carriage within a herd are discussed.

The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2018/2019

Data on antimicrobial resistance (AMR) in zoonotic and indicator bacteria from humans, animals and food are collected annually by the EU Member States (MSs), jointly analysed by the EFSA and the ECDC and reported in a yearly EU Summary Report. The annual monitoring of AMR in animals and food within the EU is targeted at selected animal species corresponding to the reporting year. The 2018 monitoring specifically focussed on poultry and their derived carcases/meat, while the monitoring performed in 2019 specifically focused on pigs and calves under 1 year of age, as well as their derived carcases/meat. Monitoring and reporting of AMR in 2018/2019 included data regarding Salmonella, Campylobacter and indicator Escherichia coli isolates, as well as data obtained from the specific monitoring of presumptive ESBL-/AmpC-/carbapenemase-producing E. coli isolates. Additionally, some MSs reported voluntary data on the occurrence of meticillin-resistant Staphylococcus aureus in animals and food, with some countries also providing data on antimicrobial susceptibility. This report provides an overview of the main findings of the 2018/2019 harmonised AMR monitoring in the main food-producing animal populations monitored, in related carcase/meat samples and in humans. Where available, data monitoring obtained from pigs, calves, broilers, laying hens and turkeys, as well as from carcase/meat samples and humans were combined and compared at the EU level, with particular emphasis on multidrug resistance, complete susceptibility and combined resistance patterns to critically important antimicrobials, as well as Salmonella and E. coli isolates possessing ESBL-/AmpC-/carbapenemase phenotypes. The outcome indicators for AMR in food-producing animals such as complete susceptibility to the harmonised panel of antimicrobials in E. coli and the prevalence of ESBL-/AmpC-producing E. coli have been also specifically analysed over the period 2015-2019.

Antimicrobial Resistance and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Slaughtered Pigs and Pork in the Central Region of Thailand

Methicillin-resistant Staphylococcus aureus (MRSA) have been a major public health concern in humans. Among MRSA, livestock-associated (LA)-MRSA strains have always been associated with exposure to livestock or their products and have emerged in different countries globally. Although studies have identified LA-MRSA from healthy pigs and pork in Thailand, prevalence in slaughtered pigs is still unknown. In addition, there are few reports on the epidemiology and molecular characteristics of LA-MRSA in Thailand. Hence, this is the first report investigating the epidemiology and molecular characteristics of MRSA in individual slaughtered pigs and pork in Thailand. A total of 204 nasal swab and 116 retailed pork samples were collected from three slaughterhouses and four fresh markets, respectively. Individual samples were used for screening for MRSA and obtained isolates were examined for drug- resistance profiling for 12 antimicrobial agents of 10 drug classes. In addition, SCCmec typing and multi-locus sequence typing were conducted to obtain genotype profiles. MRSA were isolated from 11 and 52 nasal swab and pork samples, respectively. The prevalence was significantly higher in the pork than in the nasal swab samples (p-value < 0.05). A high prevalence of ST9-SCCmecIX and ST398-SCCmecV with high-level antimicrobial resistance from markets and slaughterhouses indicated the spreading of MRSA with these genotypes in the Thai swine processing chains and suggested the need for further investigation to determine a control.

The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2017/2018

Data on antimicrobial resistance (AMR) in zoonotic and indicator bacteria from humans, animals and food are collected annually by the EU Member States (MSs), jointly analysed by EFSA and ECDC and reported in a yearly EU Summary Report. The annual monitoring of AMR in animals and food within the EU is targeted at selected animal species corresponding to the reporting year. The 2017 monitoring specifically focussed on pigs and calves under 1 year of age, as well as their derived carcases/meat, while the monitoring performed in 2018 specifically focussed on poultry and their derived carcases/meat. Monitoring and reporting of AMR in 2017/2018 included data regarding Salmonella, Campylobacter and indicator Escherichia coli isolates, as well as data obtained from the specific monitoring of ESBL-/AmpC-/carbapenemase-producing E. coli isolates. Additionally, some MSs reported voluntary data on the occurrence of meticillin-resistant Staphylococcus aureus in animals and food, with some countries also providing data on antimicrobial susceptibility. This report provides, for the first time, an overview of the main findings of the 2017/2018 harmonised AMR monitoring in the main food-producing animal populations monitored, in related carcase/meat samples and in humans. Where available, data monitoring obtained from pigs, calves/cattle, broilers, laying hens and turkeys, as well as from carcase/meat samples and humans were combined and compared at the EU level, with particular emphasis on multiple drug resistance, complete susceptibility and combined resistance patterns to critically important antimicrobials, as well as Salmonella and E. coli isolates exhibiting presumptive ESBL-/AmpC-/carbapenemase-producing phenotypes. The outcome indicators for AMR in food-producing animals, such as complete susceptibility to the harmonised panel of antimicrobials in E. coli and the prevalence of ESBL-/AmpC-producing E. coli have been also specifically analysed over the period 2014-2018.

Assessment of the Risk to Public Health due to Use of Antimicrobials in Pigs-An Example of Pleuromutilins in Denmark

Antibiotic consumption in pigs can be optimized by developing treatment guidelines, which encourage veterinarians to use effective drugs with low probability of developing resistance of importance for human health. In Denmark, treatment guidelines for use in swine production are currently under review at the Danish Veterinary and Food Administration. Use of pleuromutilins in swine has previously been associated with a very low risk for human health. However, recent international data and sporadic findings of novel resistance genes suggest a change of risk. Consequently, a reassessment was undertaken inspired by a risk assessment framework developed by the European Medicines Agency. Livestock-associated methicillin-resistant Staphylococcus aureus of clonal complex 398 (MRSA CC398) and enterococci were identified as relevant hazards. The release assessment showed that the probability of development of pleuromutilin resistance was high in MRSA CC398 (medium uncertainty) and low in enterococci (high uncertainty). A relatively small proportion of Danes has an occupational exposure to pigs, and foodborne transmission was only considered of relevance for enterococci, resulting in an altogether low exposure risk. The human consequences of infection with pleuromutilin-resistant MRSA CC398 or enterococci were assessed as low for the public in general but high for vulnerable groups such as hospitalized and immunocompromised persons. For MRSA CC398, the total risk was estimated as low (low uncertainty), among other due to the current guidelines on prevention of MRSA in place at Danish hospitals, which include screening of patients with daily contact to pigs on admittance. Moreover, MRSA CC398 has a medium human–human transmission potential. For enterococci, the total risk was estimated as low due to low prevalence of resistance, low probability of spread to humans, low virulence, but no screening of hospitalized patients, high ability of acquiring resistance genes, and a limited number of alternative antimicrobials (high uncertainty). This assessment reflects the current situation and should be repeated if pleuromutilin consumption increases substantially, resulting in increased prevalence of mobile, easily transmissible resistance mechanisms. Continuous monitoring of pleuromutilin resistance in selected human pathogens should therefore be considered. This also includes monitoring of linezolid resistance, since resistance mechanisms for pleuromutilins and oxazolidones are often coupled.

The European Union summary report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2015

The data on antimicrobial resistance in zoonotic and indicator bacteria in 2015, submitted by 28 EU Member States (MSs), were jointly analysed by EFSA and ECDC. Resistance in zoonotic Salmonella and Campylobacter from humans, animals and food, and resistance in indicator Escherichia coli as well as meticillin‐resistant Staphylococcus aureus in animals and food were addressed. ‘Microbiological’ resistance was assessed using epidemiological cut‐off (ECOFF) values; for some countries, qualitative data on human isolates were interpreted in a way which corresponds closely to the ECOFF‐defined ‘microbiological’ resistance. In Salmonella from humans, high proportions of isolates were resistant to ampicillin, sulfonamides and tetracyclines, whereas resistance to third‐generation cephalosporins was low. In Salmonella and Escherichia coli isolates from fattening pigs and calves under one year of age, resistance to ampicillin, tetracyclines and sulfonamides was frequently detected, whereas resistance to third‐generation cephalosporins was uncommon. For the first time, presumptive extended‐spectrum beta‐lactamase (ESBL)‐/AmpC‐/carbapenemase‐production in Salmonella and Escherichia coli was monitored in humans (Salmonella), meat (pork and beef), fattening pigs and calves. Varying occurrence/prevalence rates of ESBL‐/AmpC‐producers were observed between countries, and carbapenemase‐producing Escherichia coli were detected in single samples of pig meat and from fattening pigs from two MSs. Resistance to colistin was observed at low levels in Salmonella and Escherichia coli from fattening pigs and calves under one year of age and meat thereof. In Campylobacter from humans, high to extremely high proportions of isolates were resistant to ciprofloxacin and tetracyclines, particularly in C. coli. In a few countries, a third to half of C. coli in humans were resistant also to erythromycin, leaving few options for treatment of severe Campylobacter infections. High resistance to ciprofloxacin and tetracyclines was observed in C. coli isolates from fattening pigs, whereas much lower levels were recorded for erythromycin. Co‐resistance to critically important antimicrobials in both human and animal isolates was generally uncommon.

The nasal vestibulum is the optimal sampling site for MRSA screening in hospitalised horses

The increased incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection in equine hospitals highlights the need for infection control protocols based on optimal patient screening. In horses, the deep ventral meatus of the nasal cavity is the principal site sampled to detect MRSA. However, in humans, the anterior nares are the preferred sampling site. The objective of this study was to determine the optimal sampling location in the nasal chambers for MRSA in horses by comparing the results obtained from three different locations (the vestibulum, diverticulum and ventral meatus) in 240 hospitalised animals. Antimicrobial susceptibility testing and epidemiological typing were conducted on representative subsets of the isolates obtained. Compared to the more invasive ventral meatus sampling (relative sensitivity 68.9%; isolation rate 37.9%), vestibulum (RS 81.1%; IR 44.6%, P=0.13) and diverticulum (RS 52.3%; IR 28.8%, P=0.03) sampling were more or less sensitive, respectively. In total, 132 horses (55%) were MRSA positive with the vast majority (98.5%) carrying genotyped isolates of the livestock-associated (LA)-MRSA clonal complex (CC) 398, and only a minority (1.5%) CC8. Of the 22 MLST typed isolates, five belonged to a novel ST2197 (t011, CC398). Although 93.9% of the isolates were multi-resistant (to β-lactam, tetracycline, trimethoprim, and gentamicin), <5% were resistant to virtually all antimicrobials commonly used in equine medicine. The study findings indicate that detection of MRSA in horses may be enhanced by replacing the traditional deep sampling of the ventral nasal meatus by the less invasive approach of sampling the nasal vestibulum.