Emergence of methicillin resistance predates the clinical use of antibiotics.

The discovery of antibiotics more than 80 years ago has led to considerable improvements in human and animal health. Although antibiotic resistance in environmental bacteria is ancient, resistance in human pathogens is thought to be a modern phenomenon that is driven by the clinical use of antibiotics1. Here we show that particular lineages of methicillin-resistant Staphylococcus aureus-a notorious human pathogen-appeared in European hedgehogs in the pre-antibiotic era. Subsequently, these lineages spread within the local hedgehog populations and between hedgehogs and secondary hosts, including livestock and humans. We also demonstrate that the hedgehog dermatophyte Trichophyton erinacei produces two ß-lactam antibiotics that provide a natural selective environment in which methicillin-resistant S. aureus isolates have an advantage over susceptible isolates. Together, these results suggest that methicillin resistance emerged in the pre-antibiotic era as a co-evolutionary adaptation of S. aureus to the colonization of dermatophyte-infected hedgehogs. The evolution of clinically relevant antibiotic-resistance genes in wild animals and the connectivity of natural, agricultural and human ecosystems demonstrate that the use of a One Health approach is critical for our understanding and management of antibiotic resistance, which is one of the biggest threats to global health, food security and development.

Building the European Antimicrobial Resistance Surveillance network in veterinary medicine (EARS-Vet).

Antimicrobial resistance (AMR) should be tackled through a One Health approach, as stated in the World Health Organization Global Action Plan on AMR. We describe the landscape of AMR surveillance in the European Union/European Economic Area (EU/EEA) and underline a gap regarding veterinary medicine. Current AMR surveillance efforts are of limited help to veterinary practitioners and policymakers seeking to improve antimicrobial stewardship in animal health. We propose to establish the European Antimicrobial Resistance Surveillance network in Veterinary medicine (EARS-Vet) to report on the AMR situation, follow AMR trends and detect emerging AMR in selected bacterial pathogens of animals. This information could be useful to advise policymakers, explore efficacy of interventions, support antimicrobial stewardship initiatives, (re-)evaluate marketing authorisations of antimicrobials, generate epidemiological cut-off values, assess risk of zoonotic AMR transmission and evaluate the burden of AMR in animal health. EARS-Vet could be integrated with other AMR monitoring systems in the animal and medical sectors to ensure a One Health approach. Herein, we present a strategy to establish EARS-Vet as a network of national surveillance systems and highlight challenges of data harmonisation and bias. Strong political commitment at national and EU/EEA levels is required for the success of EARS-Vet.

ResFinder 4.0 for predictions of phenotypes from genotypes.

OBJECTIVES: WGS-based antimicrobial susceptibility testing (AST) is as reliable as phenotypic AST for several antimicrobial/bacterial species combinations. However, routine use of WGS-based AST is hindered by the need for bioinformatics skills and knowledge of antimicrobial resistance (AMR) determinants to operate the vast majority of tools developed to date. By leveraging on ResFinder and PointFinder, two freely accessible tools that can also assist users without bioinformatics skills, we aimed at increasing their speed and providing an easily interpretable antibiogram as output. METHODS: The ResFinder code was re-written to process raw reads and use Kmer-based alignment. The existing ResFinder and PointFinder databases were revised and expanded. Additional databases were developed including a genotype-to-phenotype key associating each AMR determinant with a phenotype at the antimicrobial compound level, and species-specific panels for in silico antibiograms. ResFinder 4.0 was validated using Escherichia coli (n = 584), Salmonella spp. (n = 1081), Campylobacter jejuni (n = 239), Enterococcus faecium (n = 106), Enterococcus faecalis (n = 50) and Staphylococcus aureus (n = 163) exhibiting different AST profiles, and from different human and animal sources and geographical origins. RESULTS: Genotype-phenotype concordance was ≥95% for 46/51 and 25/32 of the antimicrobial/species combinations evaluated for Gram-negative and Gram-positive bacteria, respectively. When genotype-phenotype concordance was <95%, discrepancies were mainly linked to criteria for interpretation of phenotypic tests and suboptimal sequence quality, and not to ResFinder 4.0 performance. CONCLUSIONS: WGS-based AST using ResFinder 4.0 provides in silico antibiograms as reliable as those obtained by phenotypic AST at least for the bacterial species/antimicrobial agents of major public health relevance considered.

Sharing more than friendship - transmission of NDM-5 ST167 and CTX-M-9 ST69 Escherichia coli between dogs and humans in a family, Finland, 2015.

IntroductionCarbapenemase-producing Enterobacteriaceae (CPE) have rarely been reported in dogs, and never in animals in Finland. However, in April 2015, two meropenem-resistant Escherichia coli were identified from two dogs in one family. Both dogs suffered from chronic otitis externa. Methods: Epidemiological and molecular investigations (pulsed-field gel electrophoresis (PFGE), multilocus sequence typing) were conducted to investigate the source of infection and transmission routes. Results: In both dogs and one family member New Delhi metallo-beta-lactamase (NDM-5)-producing multidrug-resistant ST167 E. coli was found. Whole genome sequencing confirmed that the isolates were identical or only had one or two allelic differences. Additionally, the dogs and humans of the family carried an identical extended-spectrum beta-lactamase (ESBL) CTX-M-group 9 E. coli ST69 strain, indicating interspecies transmission. While the original source remains unclear, human-to-canine transmission is possible. No carbapenems had been administered to the dogs, but exposure to numerous other antimicrobials likely sustained the bacteria and supported its propagation in the canine host. Conclusion: To our knowledge, canine clinical NDM-5 E. coli in Europe, and confirmed CPE transmission between dogs and humans have not been previously reported. The screening of veterinary Enterobacteriaceae isolates for carbapenem resistance is highly recommended.

Pilot testing the EARS-Vet surveillance network for antibiotic resistance in bacterial pathogens from animals in the EU/EEA.

Introduction: As part of the EU Joint Action on Antimicrobial Resistance (AMR) and Healthcare-Associated Infections, an initiative has been launched to build the European AMR Surveillance network in veterinary medicine (EARS-Vet). So far, activities included mapping national systems for AMR surveillance in animal bacterial pathogens, and defining the EARS-Vet objectives, scope, and standards. Drawing on these milestones, this study aimed to pilot test EARS-Vet surveillance, namely to (i) assess available data, (ii) perform cross-country analyses, and (iii) identify potential challenges and develop recommendations to improve future data collection and analysis. Methods: Eleven partners from nine EU/EEA countries participated and shared available data for the period 2016-2020, representing a total of 140,110 bacterial isolates and 1,302,389 entries (isolate-antibiotic agent combinations). Results: Collected data were highly diverse and fragmented. Using a standardized approach and interpretation with epidemiological cut-offs, we were able to jointly analyze AMR trends of 53 combinations of animal host-bacteria-antibiotic categories of interest to EARS-Vet. This work demonstrated substantial variations of resistance levels, both among and within countries (e.g., between animal host species). Discussion: Key issues at this stage include the lack of harmonization of antimicrobial susceptibility testing methods used in European surveillance systems and veterinary diagnostic laboratories, the absence of interpretation criteria for many bacteria-antibiotic combinations of interest, and the lack of data from a lot of EU/EEA countries where little or even surveillance currently exists. Still, this pilot study provides a proof-of-concept of what EARS-Vet can achieve. Results form an important basis to shape future systematic data collection and analysis.

Genomic characterization of ESBL/AmpC-producing and high-risk clonal lineages of Escherichia coli and Klebsiella pneumoniae in imported dogs with shelter and stray background.

OBJECTIVES: Extended spectrum ß-lactamase (ESBL)- and ampicillinase C (AmpC)-carrying Enterobacteriaceae have been widely reported among companion animals. According to previous studies, dogs with a shelter or stray background might be at risk of carrying such bacteria. The aim of this study was to explore, with whole-genome sequencing (WGS), the genomic characteristics of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolated from imported dogs with a stray or shelter background. METHODS: E. coli (n = 58) and K. pneumoniae (n = 2) isolates from imported dogs originating from seven countries were included. Phenotypic resistance was investigated by selective isolation and antibiotic susceptibility testing. Whole-genome sequencing was used to study the genomic characteristics and the presence of antimicrobial resistance genes (ARGs) and virulence determinants of the ESBL/AmpC-producing E. coli and K. pneumoniae isolates. RESULTS: A high diversity of different ARGs (n = 56) and sequence types (STs) (n = 32), including high-risk clonal lineages ST410 (n = 3) and ST307 (n = 1), was identified in E. coli and K. pneumoniae isolates, respectively. Genes encoding resistance to ß-lactams accounted for the majority, with the most frequent being blaCTX-M-15. Moreover, 17 (29%) E. coli isolates qualified as presumptive extraintestinal pathogenic and/or uropathogenic E. coli. CONCLUSIONS: Our results highlight the multiplicity of genetic backgrounds disseminating ESBL/AmpC-genes in the studied dogs, calling for further investigation of possible drivers responsible for the dissemination of ARGs in animal shelters and amongst stray dogs. From a public health perspective, enhanced genomic surveillance of ESBL/AmpC-producing Enterobacteriaceae in dogs is needed in Finland.

Characterisation of and risk factors for extended-spectrum ß-lactamase producing Enterobacterales (ESBL-E) in an equine hospital with a special reference to an outbreak caused by Klebsiella pneumoniae ST307:CTX-M-1.

BACKGROUND: Extended-spectrum ß-lactamase producing Enterobacterales (ESBL-E) are important causative agents for infections in humans and animals. At the Equine Veterinary Teaching Hospital of the University of Helsinki, the first infections caused by ESBL-E were observed at the end of 2011 leading to enhanced infection surveillance. Contact patients were screened for ESBL-E by culturing infection sites and rectal screening. This study was focused on describing the epidemiology and microbiological characteristics of ESBL-E from equine patients of the EVTH during 2011-2014, and analysing putative risk factors for being positive for ESBL-E during an outbreak of Klebsiella pneumoniae ST307. RESULTS: The number of ESBL-E isolations increased through 2012-2013 culminating in an outbreak of multi-drug resistant K. pneumoniae ST307:blaCTX-M-1:blaTEM:blaSHV during 04-08/2013. During 10/2011-05/2014, altogether 139 ESBL-E isolates were found from 96 horses. Of these, 26 were from infection-site specimens and 113 from rectal-screening swabs. A total of 118 ESBL-E isolates from horses were available for further study, the most numerous being K. pneumoniae (n = 44), Escherichia coli (n = 31) and Enterobacter cloacae (n = 31). Hospital environmental specimens (N = 47) yielded six isolates of ESBL-E. Two identical E. cloacae isolates originating from an operating theatre and a recovery room had identical or highly similar PFGE fingerprint profiles as five horse isolates. In the multivariable analysis, mare-foal pairs (OR 4.71, 95% CI 1.57-14.19, P = 0.006), length of hospitalisation (OR 1.62, 95% CI 1.28-2.06, P < 0.001) and passing of a nasogastric tube (OR 2.86, 95% CI 1.03-7.95, P = 0.044) were associated with being positive for ESBL-E during the K. pneumoniae outbreak. CONCLUSIONS: The occurrence of an outbreak caused by a pathogenic ESBL-producing K. pneumoniae ST307 strain highlights the importance of epidemiological surveillance of ESBL-E in veterinary hospitals. Limiting the length of hospitalisation for equine patients may reduce the risk of spread of ESBL-E. It is also important to acknowledge the importance of nasogastric tubing as a potential source of acquiring ESBL-E. As ESBL-E were also found in stomach drench pumps used with nasogastric tubes, veterinary practices should pay close attention to appropriate equipment cleaning procedures and disinfection practices.

Low-level colonization of methicillin-resistant Staphylococcus aureus in pigs is maintained by slowly evolving, closely related strains in Finnish pig farms.

BACKGROUND: Over the past two decades, livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has become widely prevalent in pig production in Europe. The carriage status of LA-MRSA is known to vary among individual pigs, but bacterial load in pigs has rarely been studied. We assessed the quantity of LA-MRSA in nasal and skin samples of pigs and investigated the genetic diversity of the strains together with sequenced strains from national surveillance and pathology samples from the Finnish Food Authority. On two farms with assumed MRSA-positive status, farm 1 and farm 2, 10 healthy pigs were sampled three times during 2 weeks from the nares and skin (study A). On farm 1, 54 additional pigs were sampled and from confirmed MRSA-positive animals, 10 were randomly selected and transported to a clean, controlled environment for further sampling (study B). From the samples taken on farms 1 and 2 and in the controlled environment, MRSA was isolated both by direct plating and enrichment on selective media. spa types, multilocus sequence types, staphylococcal cassette chromosome mec types, resistance and virulence genes were determined. Core genome multilocus sequence typing (cgMLST) analysis was performed, including the sequences deriving from the surveillance/pathology samples from the Finnish Food Authority. RESULTS: All pigs on farm 1 carried LA-MRSA in the nares at all three time points and five pigs on farm 2 at one time point. Nasal quantity varied between 10 and 103 CFU/swab and quantity on the skin between 10 and 102 CFU/swab. In the controlled environment, MRSA was detected in at least one of the nasal samples from each animal. spa type t034 was predominant. cgMLST showed one cluster with minimum allele differences between 0 and 11. CONCLUSIONS: The study shows predominantly low-level carriage (< 103 CFU/swab) of LA-MRSA on farms. In the controlled environment we observed a decline in nasal carriage but constant skin carriage. cgMLST showed that strains of spa type t034 are closely related at the national level.

Antimicrobial Use and Susceptibility of Indicator Escherichia coli in Finnish Integrated Pork Production.

In pigs, antimicrobial use (AMU) practices vary at different production phases between herds and between countries. Antimicrobial resistance (AMR) development is linked to AMU but recognized as a multi-factorial issue, and thus, any information increasing knowledge of AMU and AMR relationships is valuable. We described AMU and screened the carriage of different AMR phenotypes of indicator Escherichia coli in 25 selected Finnish piglet-producing and finishing herds that formed nine birth-to-slaughter production lines. Moreover, we studied associations between AMU and AMR in both herd types and throughout the production line. Treatment records were obtained from the national Sikava register for 1year, and AMU was quantified as mg/PCU (population correction unit) and TIs (treatment incidences). For phenotypic antimicrobial susceptibility testing, ten pen-level pooled feces samples (n=250) in each herd were collected from one room representing the oldest weaned piglets or the oldest finishing pigs. Majority of the medications (96.8%) was administered parenterally, and penicillin was the predominant antimicrobial in every herd. More different antimicrobial substances were used in piglet-producing than in finishing herds (median 5 and 1, respectively, p<0.001). As mg/PCU, sows had the highest AMU and suckling piglets had the highest TIs, whereas finishing pigs were the least treated age group. The proportion of susceptible indicator E. coli isolates of all studied isolates was 59.6%. Resistance was found most commonly against tetracycline, sulfamethoxazole, trimethoprim, and ampicillin, and multi-resistant (MR) isolates (46.5% of all resistant isolates) were resistant to a maximum of four different antimicrobials. Quinolone resistance was rare, and no resistance against 3rd-generation cephalosporins, meropenem, azithromycin, colistin, gentamicin, or tigecycline was detected. The main associations between AMU and AMR were found at antimicrobial group level when use was compared with the presence of AMR phenotypes. The proportion of resistant isolates was not associated with AMU, and herd size was not associated with either AMU or AMR. We suggest that the use of narrow-spectrum beta-lactams as a primary treatment option and lack of wide application of oral group medications potentially favors a good resistance pattern in integrated pork production.

Plasmid-Borne and Chromosomal ESBL/AmpC Genes in Escherichia coli and Klebsiella pneumoniae in Global Food Products.

Plasmid-mediated extended-spectrum beta-lactamase (ESBL), AmpC, and carbapenemase producing Enterobacteriaceae, in particular Escherichia coli and Klebsiella pneumoniae, with potential zoonotic transmission routes, are one of the greatest threats to global health. The aim of this study was to investigate global food products as potential vehicles for ESBL/AmpC-producing bacteria and identify plasmids harboring resistance genes. We sampled 200 food products purchased from Finland capital region during fall 2018. Products originated from 35 countries from six continents and represented four food categories: vegetables (n = 60), fruits and berries (n = 50), meat (n = 60), and seafood (n = 30). Additionally, subsamples (n = 40) were taken from broiler meat. Samples were screened for ESBL/AmpC-producing Enterobacteriaceae and whole genome sequenced to identify resistance and virulence genes and sequence types (STs). To accurately identify plasmids harboring resistance and virulence genes, a hybrid sequence analysis combining long- and short-read sequencing was employed. Sequences were compared to previously published plasmids to identify potential epidemic plasmid types. Altogether, 14 out of 200 samples were positive for ESBL/AmpC-producing E. coli and/or K. pneumoniae. Positive samples were recovered from meat (18%; 11/60) and vegetables (5%; 3/60) but were not found from seafood or fruit. ESBL/AmpC-producing E. coli and/or K. pneumoniae was found in 90% (36/40) of broiler meat subsamples. Whole genome sequencing of selected isolates (n = 21) revealed a wide collection of STs, plasmid replicons, and genes conferring multidrug resistance. bla CTX-M-15-producing K. pneumoniae ST307 was identified in vegetable (n = 1) and meat (n = 1) samples. Successful IncFII plasmid type was recovered from vegetable and both IncFII and IncI1-Iγ types from meat samples. Hybrid sequence analysis also revealed chromosomally located beta-lactamase genes in two of the isolates and indicated similarity of food-derived plasmids to other livestock-associated sources and also to plasmids obtained from human clinical samples from various countries, such as IncI type plasmid harboring bla TEM-52C from a human urine sample obtained in the Netherlands which was highly similar to a plasmid obtained from broiler meat in this study. Results indicate certain foods contain bacteria with multidrug resistance and pose a possible risk to public health, emphasizing the importance of surveillance and the need for further studies on epidemiology of epidemic plasmids.

Antimicrobial use, biosecurity, herd characteristics, and antimicrobial resistance in indicator Escherichia coli in ten Finnish pig farms.

We investigated connections between antimicrobial use (AMU), biosecurity, and the numbers of pigs and staff in ten Finnish farrow-to-finish herds. Data on AMU in each herd were collected for 12 months. AMU was quantified as treatment incidences per 1000 days at risk (TI) using the consensus defined daily dose calculation. Biosecurity was scored using the Biocheck.UGent™ system. We also examined antimicrobial resistance patterns of indicator E. coli isolated from faeces of selected pigs. In each herd, two groups of five pigs were formed: 1) antimicrobial treatment group (ANT: at least one pig in the litter was identified as sick and treated with antimicrobials) and 2) non-antimicrobial treatment group (NON: the litter was not medicated). Faecal samples were taken from these pigs at 5 and 22 weeks of age, cultured, and indicator E. coli isolates were tested for antimicrobial susceptibilities. The AMU varied considerably between the herds. Altogether, most of the antimicrobial treatment courses were assigned to weaned piglets. When AMU was quantified as TIs, suckling piglets had the highest TI (mean 46.6), which was significantly higher (P < 0.05) than TIs in fatteners and breeders (9.3 and 7.3, respectively). The difference between TI in suckling and TI in weaned piglets (19.1) was not statistically significant. There was a tendency for a negative correlation between the TI in breeders and the number of sows (r = -0.56, P = 0.09). Larger herds had higher external biosecurity scores than smaller herds (LS-means; 72 vs. 66, P < 0.05). The proportions of E. coli isolates resistant to at least one antimicrobial were higher in pigs at 5 weeks than in pigs at 22 weeks of age (Binomial proportion means; 40.5 % vs. 15.5 %, P < 0.05); as well as proportions of isolates resistant to at least three antimicrobial classes (23.0 % vs. 3.7 %, P < 0.01). These proportions did not differ between the ANT and NON groups at either 5 or 22 weeks of age (P> 0.05). We found few connections: enhanced external biosecurity levels found in the large herds co-occurred with lower use of antimicrobials and herds with low biosecurity scores - especially in the internal subcategories - appeared to have higher proportions of resistant isolates. Conclusively, we suggest that enhancing internal biosecurity might contribute to a reduction in the spreading of antimicrobial resistance in pig herds.

Etiology of acute respiratory disease in fattening pigs in Finland.

BACKGROUND: The objective of our study was to clinically and etiologically investigate acute outbreaks of respiratory disease in Finland. Our study also aimed to evaluate the clinical use of various methods in diagnosing respiratory infections under field conditions and to describe the antimicrobial resistance profile of the main bacterial pathogen(s) found during the study. METHODS: A total of 20 case herds having finishing pigs showing acute respiratory symptoms and eight control herds showing no clinical signs suggesting of respiratory problems were enrolled in the study. Researchers visited each herd twice, examining and bleeding 20 pigs per herd. In addition, nasal swab samples were taken from 20 pigs and three pigs per case herd were necropsied during the first visit. Serology was used to detect Actinobacillus pleuropneumoniae (APP), swine influenza virus (SIV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine respiratory coronavirus (PRCV) and Mycoplasma hyopneumoniae antibodies. Polymerase chain reaction (PCR) was used to investigate the presence of porcine circovirus type 2 (PCV2) in serum and SIV in the nasal and lung samples. Pathology and bacteriology, including antimicrobial resistance determination, were performed on lung samples obtained from the field necropsies. RESULTS: According to the pathology and bacteriology of the lung samples, APP and Ascaris suum were the main causes of respiratory outbreaks in 14 and three herds respectively, while the clinical signs in three other herds had a miscellaneous etiology. SIV, APP and PCV2 caused concurrent infections in certain herds but they were detected serologically or with PCR also in control herds, suggesting possible subclinical infections. APP was isolated from 16 (80%) case herds. Marked resistance was observed against tetracycline for APP, some resistance was detected against trimethoprim/sulfamethoxazole, ampicillin and penicillin, and no resistance against florfenicol, enrofloxacin, tulathromycin or tiamulin was found. Serology, even from paired serum samples, gave inconclusive results for acute APP infection diagnosis. CONCLUSIONS: APP was the most common cause for acute respiratory outbreaks in our study. SIV, A. suum, PCV2 and certain opportunistic bacteria were also detected during the outbreaks; however, viral pathogens appeared less important than bacteria. Necropsies supplemented with microbiology were the most efficient diagnostic methods in characterizing the studied outbreaks.

Species distribution and in vitro antimicrobial susceptibility of coagulase-negative staphylococci isolated from bovine mastitic milk.

BACKGROUND: Coagulase-negative staphylococci (CoNS) are the most common bovine mastitis causing bacteria in many countries. It is known that resistance for antimicrobials is in general more common in CoNS than in Staphylococcus aureus but little is known about the antimicrobial resistance of specific CoNS species. In this study, 400 CoNS isolates from bovine mastitic milk samples were identified to species level using ribotyping and MALDI-TOF MS, and their antimicrobial susceptibility was determined using a commercially available microdilution system. The results were interpreted according to the epidemiological cut-off values by the European Committee on Antimicrobial Susceptibility testing. RESULTS: The most common CoNS species were S. simulans, S. epidermidis, S. chromogenes and S. haemolyticus. Penicillin resistance was the most common type of antimicrobial resistance. Staphylococcus epidermidis was the most resistant among the four major species. Almost one-third of our S. epidermidis isolates were resistant to >2 antimicrobials and close to 7 % were multidrug resistant. The majority of S. epidermidis isolates were resistant to benzylpenicillin. On the contrary, only few S. simulans isolates were penicillin-resistant. Phenotypic oxacillin resistance was found in all four main species, and 34 % of the isolates were oxacillin resistant. However, only 21 isolates (5 %) were positive for the mecA gene. Of these, 20 were S. epidermidis and one S. sciuri. mecC positive isolates were not found. CONCLUSION: Staphylococcus epidermidis differed from the three other major CoNS species as resistance to the tested antimicrobials was common, several isolates were multidrug resistant, and 19 % of the isolates carried the mecA gene encoding methicillin resistance.

Livestock-Associated Methicillin Resistant and Methicillin Susceptible Staphylococcus aureus Sequence Type (CC)1 in European Farmed Animals: High Genetic Relatedness of Isolates from Italian Cattle Herds and Humans.

Methicillin-resistant Staphylococcus aureus (MRSA) Sequence Type (ST)1, Clonal Complex(CC)1, SCCmec V is one of the major Livestock-Associated (LA-) lineages in pig farming industry in Italy and is associated with pigs in other European countries. Recently, it has been increasingly detected in Italian dairy cattle herds. The aim of this study was to analyse the differences between ST1 MRSA and methicillin-susceptible S. aureus (MSSA) from cattle and pig herds in Italy and Europe and human isolates. Sixty-tree animal isolates from different holdings and 20 human isolates were characterized by pulsed-field gel electrophoresis (PFGE), spa-typing, SCCmec typing, and by micro-array analysis for several virulence, antimicrobial resistance, and strain/host-specific marker genes. Three major PFGE clusters were detected. The bovine isolates shared a high (≥90% to 100%) similarity with human isolates and carried the same SCCmec type IVa. They often showed genetic features typical of human adaptation or present in human-associated CC1: Immune evasion cluster (IEC) genes sak and scn, or sea; sat and aphA3-mediated aminoglycoside resistance. Contrary, typical markers of porcine origin in Italy and Spain, like erm(A) mediated macrolide-lincosamide-streptograminB, and of vga(A)-mediated pleuromutilin resistance were always absent in human and bovine isolates. Most of ST(CC)1 MRSA from dairy cattle were multidrug-resistant and contained virulence and immunomodulatory genes associated with full capability of colonizing humans. As such, these strains may represent a greater human hazard than the porcine strains. The zoonotic capacity of CC1 LA-MRSA from livestock must be taken seriously and measures should be implemented at farm-level to prevent spill-over.

Large outbreak caused by methicillin resistant Staphylococcus pseudintermedius ST71 in a Finnish Veterinary Teaching Hospital--from outbreak control to outbreak prevention.

INTRODUCTION: The purpose of this study was to describe a nosocomial outbreak caused by methicillin resistant Staphylococcus pseudintermedius (MRSP) ST71 SCCmec II-III in dogs and cats at the Veterinary Teaching Hospital of the University of Helsinki in November 2010 - January 2012, and to determine the risk factors for acquiring MRSP. In addition, measures to control the outbreak and current policy for MRSP prevention are presented. METHODS: Data of patients were collected from the hospital patient record software. MRSP surveillance data were acquired from the laboratory information system. Risk factors for MRSP acquisition were analyzed from 55 cases and 213 controls using multivariable logistic regression in a case-control study design. Forty-seven MRSP isolates were analyzed by pulsed field gel electrophoresis and three were further analyzed with multi-locus sequence and SCCmec typing. RESULTS: Sixty-three MRSP cases were identified, including 27 infections. MRSPs from the cases shared a specific multi-drug resistant antibiogram and PFGE-pattern indicated clonal spread. Four risk factors were identified; skin lesion (OR = 6.2; CI95% 2.3-17.0, P = 0.0003), antimicrobial treatment (OR = 3.8, CI95% 1.0-13.9, P = 0.0442), cumulative number of days in the intensive care unit (OR = 1.3, CI95% 1.1-1.6, P = 0.0007) or in the surgery ward (OR = 1.1, CI95% 1.0-1.3, P = 0.0401). Tracing and screening of contact patients, enhanced hand hygiene, cohorting and barrier nursing, as well as cleaning and disinfection were used to control the outbreak. To avoid future outbreaks and spread of MRSP a search-and-isolate policy was implemented. Currently nearly all new MRSP findings are detected in screening targeted to risk patients on admission. CONCLUSION: Multidrug resistant MRSP is capable of causing a large outbreak difficult to control. Skin lesions, antimicrobial treatment and prolonged hospital stay increase the probability of acquiring MRSP. Rigorous control measures were needed to control the outbreak. We recommend the implementation of a search-and-isolate policy to reduce the burden of MRSP.

Occurrence and characterization of methicillin-resistant staphylococci from bovine mastitis milk samples in Finland.

BACKGROUND: Methicillin-resistant staphylococci (MRS) are increasingly being isolated in bovine mastitis. The aim of our study was to evaluate the occurrence of MRS in Finnish mastitis milk samples and characterize the MRS isolates using molecular methods. RESULTS: Methicillin-resistant S. aureus (MRSA) was a rare finding in bovine mastitis in Finland. Only two out of 135 (1.5%) S. aureus isolates were positive for mec genes. One of these carried mecA and was of spa type t172, SCCmec type IV and ST375, and the other harboured mecC, being spa type t3256, and ST130. MRSA ST375 is common among human MRSA isolates in Finland, but this is the first report in the country of bovine mecC MRSA. In coagulase-negative staphylococci (CoNS) originating from bovine mastitis, methicillin resistance was more common. In the two CoNS collections studied, 5.2% (17/324) and 1.8% (2/110) of the isolates were mecA positive. Eighteen of these were methicillin-resistant S. epidermidis (MRSE), which were divided into 6 separate PFGE clusters. One pulsotype was detected in different parts of the country, indicating clonal spread. Most MRSE (13/18) were of SCCmec type IV, one was of type V and four were non-typeable. Comparison with a human staphylococcal database indicated that bovine MRSE strains were not closely related to human MRSE isolates. CONCLUSIONS: The occurrence of MRS, especially MRSA, in bovine mastitis in Finland was low. Most methicillin-resistant bovine CoNS are MRSE, and we found evidence of a bovine MRSE strain that may spread clonally. This is the first report of a Finnish bovine isolate of MRSAmecC ST130. The study provides a baseline for further MRS monitoring.