SCC <Emphasis Type="Italic">mec</Emphasis> typing and antimicrobial resistance of methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA) from pigs of Northeast India

Staphylococcus aureus is one of the most important pathogens of both humans and animal. Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that causes serious infections both in hospitals and communities due to its multidrug resistance tendency. This study was undertaken to characterize the MRSA isolates from pigs and to determine the antimicrobial resistance of these isolates. Forty nine MRSA strains (one strain per positive pig) isolated from pigs of Northeast India were characterized by SCCmec typing and antimicrobial resistance. The overall prevalence of MRSA was 7.02 % with the highest prevalence recorded in pigs aged 1–3 months (P = 0.001) and in nasal samples (P = 0.005). Two SCC mec types (type III and V) were found in Indian pigs with predominance of type V. All isolates were resistant to penicillin. Seventeen resistance groups were observed where 87.75 % isolates showed multidrug resistance (showed resistance to three or more classes of antimicrobials). The most predominant resistance pattern observed was Oxytetracycline + Penicillin + Sulfadiazine + Tetracycline accounting 12.24 % of the isolates. The present study contributes to the understanding of characteristics and antimicrobial resistance of porcine MRSA isolates which in turn will help in devising strategy for the control of this pathogen. Findings of the study also throw light on multidrug resistance MRSA and emphasize the need for judicious use of antimicrobials in animal practice.     

Carriage of methicillin-resistant Staphylococcus pseudintermedius in small animal veterinarians: indirect evidence of zoonotic transmission

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is increasingly reported in small animals and cases of human infections have already been described despite its recent emergence in veterinary practice. We investigated the prevalence of MRSP and methicillin-resistant Staphylococcus aureus (MRSA) among small animal dermatologists attending a national veterinary conference in Italy. Nasal swabs were obtained from 128 veterinarians, seven of which harboured MRSP (n = 5; 3.9%) or MRSA (n = 2; 1.6%). A follow-up study of two carriers revealed that MRSP persisted for at least 1 month in the nasal cavity. Methicillin-susceptible S. aureus (MSSA) was isolated from 32 (25%) conference participants, whereas methicillin-susceptible S. pseudintermedius (MSSP) was not detected, suggesting that MRSP may have a particular ability to colonize humans compared to MSSP. All isolates were characterized by spa typing. Methicillin-resistant isolates were further typed by antimicrobial susceptibility testing, SCCmec and multi-locus sequence typing. Two lineages previously associated with pets were identified among the five MRSP isolates; the European epidemic clone ST71-SCCmec II-III and ST106-SCCmec IV. One of the two MRSA isolates displayed a genotype (ST22- SCCmecIV) frequently reported in dogs and cats. MRSP isolates were resistant to more antimicrobial agents compared with MRSA isolates and displayed the typical multidrug resistance patterns of MRSP in pets. The 32 MSSA isolates belonged to 20 spa types and the most frequent types (t12, t15 and t166) were associated with common S. aureus lineages in humans (CC30 and CC45). Although low, the 3.9% MRSP carriage rate found among small animal dermatologists was surprising in consideration of the rare occurrence of S. pseudintermedius in humans, the lack of MSSP detection and the recent appearance of MRSP in Europe. As cases of human MRSP infection have been linked with pets, veterinarians should be aware of this zoonotic risk and proper preventative measures should be taken to avoid MRSP transmission from animal patients.     

Antimicrobial resistance and population structure of Staphylococcus epidermidis recovered from pig farms in Belgium

Pigs are known to harbour a variety of staphylococcal bacteria, including Staphylococcus epidermidis, in the upper respiratory tract. The aim of the present study was to determine the prevalence, genetic diversity, virulence and antimicrobial resistance of S. epidermidis in healthy pigs, as well as to identify the potential role of pigs as a reservoir of zoonotic infection.The overall prevalence of S. epidermidis carriage was 28%, with approximately half of the pigs tested (13.5%) carrying methicillin-resistant S. epidermidis (MRSE). Some isolates belonged to multilocus sequence types, associated with healthy human carriers or healthcare personnel (ST88, ST210) whereas others were related to animal or environmental strains (ST100, ST273). Most MRSE isolates carried SCCmec type IV, with SCCmec type V or a non-typeable SCCmec detected in the remaining isolates. Both MRSE and methicillin-susceptible S. epidermidis isolates showed a degree of antimicrobial resistance, with most resistant to tetracycline and/or trimethoprim antimicrobial drugs. Isolates subjected to micro-array analysis carried the antimicrobial resistance genes tet(K), tet(M) and dfrS1, while half carried the arginine catabolic element (ACME) associated with colonisation. Some MRSE ST273 strains also carried the ica operon involved in biofilm formation. These research findings provide insight into the population structure and characteristics of S. epidermidis carried by healthy pigs, suggesting a role for these strains as a potential reservoir for antimicrobial and virulence genes and indicating that exchange of strains might occur between pigs and humans.     

Misuse of Antimicrobials and Selection of Methicillin‐Resistant Staphylococcus pseudintermedius Strains in Breeding Kennels: Genetic Characterization of Bacteria After a Two‐year Interval

Methicillin‐resistant Staphylococcus pseudintermedius (MRSP) strains have been isolated from dogs with increasing frequency; prolonged or excessive use of antimicrobials is associated with the selection of MRSP, and misuse of antimicrobials is frequent in breeding kennels. This study was carried out in two breeding kennels (A and B) in which we had isolated MRSP in 2008: the aim was to assess colonization of previously positive bitches and of other bitches sharing the same environment and to assess the genetic profile of both the old and the new strains [spa typing, staphylococcal cassette chromosome mec (SCCmec) typing and Pulsed‐field Gel Electrophoresis (PFGE)]. Six animals from Kennel A (two from 2008) and eight from Kennel B (one from 2008) were tested: 16 MRSP strains were isolated only from bitches housed in Kennel B. Old and new isolates were mecA positive, resulted spa type t02 and carried SSCmec II–III. PGFE showed that all isolates were related and belonged to the main clone lineage dominating in Europe, ST71‐J‐t02‐II–III. Kennels A and B differ in the use of antimicrobials, which has been reduced over time in Kennel A, while has remained excessive in Kennel B, where many agents belonging to different classes (third‐generation cephalosporins, fluoroquinolones, macrolids) are administered to dogs, without veterinary supervision, especially around parturition. Misuse of antimicrobials is the key factor for the selection of MRSP strains in healthy dogs and for their persistence over time. Dog breeders should be aware that infections caused by multiresistant bacteria have very limited therapeutical options and represent a huge challenge for animal health.     

Antimicrobial susceptibilities and population structure of Staphylococcus epidermidis associated with ovine mastitis

Intramammary infections are a serious problem for dairy sheep farms, and Staphylococcus epidermidis is one of the main etiological agents of ovine mastitis. In this work, 131 S. epidermidis isolates, collected from 2201 dairy Sarda sheep belonging to 14 flocks with high somatic cell count scores, were studied. The flocks were located in diverse geographical areas of Sardinia, Italy. The aim of study was to assess the susceptibility of isolates to 13 antimicrobial agents, many of which are frequently used in mastitis therapy. Oxacillin was used for detecting methicillin-resistant S. epidermidis (MRSE) by disk diffusion test. Thirty-eight percent of the isolates (n = 50) were resistant to penicillin, 7.6% (n = 10) were resistant to tetracycline, and 2.3% (n = 3) were resistant to both penicillin and tetracycline (PTRSE). Two isolates were resistant to five antimicrobials including methicillin. Analysis of staphylococcal cassette chromosome mec (SCCmec) elements showed that both MRSE isolates harbored SCCmec type IVa. Based on pulsed-field gel electrophoresis (PFGE) typing by SmaI macrorestriction, S. epidermidis isolates were grouped into four clusters at 75% similarity level. The two multi-drug resistant MRSE isolates displayed distinct PFGE patters. This study indicates that S. epidermidis isolates from sheep milk samples may accumulate resistance markers for different antimicrobial agents. Furthermore, the occurrence of PTRSE and MRSE suggests to adopt adequate hygienic measures when handling animals with intramammary infections, in order to prevent spreading PTRSE and MRSE strains to humans through direct contact and/or consumption of contaminated food.     

Detection and characterization of methicillin-resistant Staphylococcus pseudintermedius in healthy dogs in La Rioja, Spain

The objective was to identify the methicillin-resistant coagulase-positive staphylococci (MRCoPS) nasal carriage rate of healthy dogs in La Rioja (Spain) and to characterize the recovered isolates by different molecular techniques. Nasal samples from 196 dogs were obtained (98 household-dogs, 98 pound-dogs). Isolates were identified and characterized by spa-, SCCmec- and MLST-typing, SmaI-PFGE, antimicrobial susceptibility, determination of antimicrobial resistance and toxin genes profiling. S. pseudintermedius was the only species recovered. Nine methicillin-resistant S. pseudintermedius (MRSP) were obtained from 9 of 196 sampled dogs (8% pound-dogs, 1% household-dogs). MRSP isolates were typed (MLST/PFGE/spa/SCCmec) as: ST71/A/t02/II–III (7 isolates), ST92/C/t06/V (1 isolate), and ST26/B/non-typable/non-typable (1 isolate). All MRSP were resistant to [resistance gene/number isolates]: β-lactams [mecA + blaZ/9], tetracycline [tet(K)/7, tet(M)/2], macrolides and lincosamides [erm(B)/9], aminoglycosides [aacA-aphD + aadE + aphA-3/9], and co-trimoxazol [dfr(G)/9]. Eight MRSP isolates showed also resistance to fluoroquinolones and amino acid changes in GyrA [Ser84Leu + Glu714Lys, 7 isolates; Ser84Leu, 1 isolate] and GrlA [Ser80Ile, 8 isolates] proteins were detected. The remaining isolate was chloramphenicol resistant and harboured cat_pC221 gene. All MRSP isolates harboured the aadE-sat4-aphA-3 multiresistance-gene-cluster linked to erm(B) gene as well as the siet, si-ent and lukS/F-I toxin genes. MRSP is a moderately common (4.6%) colonizer of healthy dogs in Spain. A major MRSP lineage (ST71) was detected and its future evolution should be tracked.     

Methicillin-resistant Staphylococcus pseudintermedius among dogs admitted to a small animal hospital

The aim of this study was to determine the frequency of carriage of methicillin-resistant Staphylococcus pseudintermedius (MRSP) among dogs admitted to a small animal hospital during a 17-month period, to characterize these isolates and to initially screen for possible factors associated with MRSP carriage. Swabs were taken from the nose/pharynx and the perineum as well as from wounds and skin infections (if present) of 814 dogs before entering the small animal hospital. A questionnaire for background information was completed. The staphylococcal species and methicillin resistance were confirmed pheno- and genotypically. The identified MRSP isolates were characterized by SCCmec typing, testing for susceptibility to 25 antimicrobial agents and SmaI-directed pulsed-field gel electrophoresis. A first screening for possible risk factors for MRSP carriage was performed by means of unifactorial contingency tables and CART analysis. Sixty (7.4%) dogs were positive for MRSP. All MRSP isolates harboured a type II-III SCCmec cassette and showed extended resistance to antimicrobial agents. Fifteen different SmaI patterns were observed. The major factors that clustered with MRSP carriage were former hospitalization and antibiotic treatment within the last six months before sampling. This study showed that only a minor part of the sampled dogs carried multi-resistant MRSP isolates. The facts that prior hospitalization and/or antibiotic therapy are potential associated factors for MRSP carriage underline the necessity of a judicious use of antibiotics in small animal medicine.     

Epidemiology of methicillin resistant Staphylococcus pseudintermedius in guide dogs in Finland

Background

Methicillin resistant Staphylococcus pseudintermedius (MRSP) and Staphylococcus aureus (MRSA) are common multi-drug resistant (MDR) bacteria in dogs. In 2012–2013 three dogs of the Guide Dog School of the Finnish Federation of the Visually Impaired were found to be MRSP positive. Guide dogs have regular contact with each other during their first year of life and prolonged contact when in training. Since dogs are placed in different parts of Finland after training, there is a risk for national spread of MDR bacteria. In this study the prevalence of MRSP and MRSA, as well as the risk factors for MRSP were determined in the Finnish guide dog population. MRSP isolates were investigated using molecular methods and compared to the earlier isolates.

Results

Out of 132 tested dogs 4 were MRSP positive thus giving the prevalence estimate of 3% (95% CI: 1–8%) for MRSP in the target population. MRSA was not detected (prevalence estimate 0%, 95% CI: 0–3%). Risk factors associated with MRSP were being a breeding bitch (OR = 8.4; 95% CI: 1.1–64.1, P = 0.012), the number of veterinary visits (OR = 1.23; 95% CI: 1.0–1.5, P = 0.025) and number of antimicrobial courses (OR = 1.63; 95% CI: 1.0–2.55; P = 0.035). Identified MRSP isolates belonged to five different sequence types (ST45, 71, 402, 403 and 404). All ST71 isolates carried SCCmec II-III, while the SCCmec type of the ST45 and ST402 (a single locus variant of ST45) isolates were non-typeable with the method used.

Conclusions

MRSP and MRSA had low prevalence in the studied dog population despite the close contact between dogs, and the MRSP population was heterogenic. Antimicrobial therapy and veterinary visits are risk factors for MRSP even among a small case group.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-015-0129-8) contains supplementary material, which is available to authorized users.     

Prevalence of canine methicillin resistant Staphylococcus pseudintermedius in a veterinary diagnostic laboratory in Italy

The overall prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) was 2% (10/590) among 590 canine specimens submitted to an Italian veterinary diagnostic laboratory during a two-month period, and 21% (10/48) among Staphylococcus intermedius group (SIG) isolates. All methicillin-resistant strains exhibited additional resistance to fluoroquinolones, gentamicin, lincosamides, tetracyclines, and potentiated sulfonamides, belonged predominantly to spa type t02 and harboured SCCmec type II–III cassette.     

Multidrug- and methicillin resistant Staphylococcus pseudintermedius as a cause of canine pyoderma: a case report

A case of a dog with a long-term inflammatory skin disorder due to infection with methicillin-resistant Staphylococcus pseudintermedius (MRSP) is described. After initial diagnostics of MRSP, follow-up swabs of the dog (nose, skin) were taken twice after four and seven weeks. MRSP was constantly isolated from the skin and once from the nose. Since infected humans might be a source of reinfection, the owners of the dog were screened (nasal) three times during their pet's therapy. Thereby, the male owner was found to be colonized with MRSP once in the first sampling round. Comparative typing of all MRSP-isolates by pulsed-field gel electrophoresis (PFGE), SCCmec typing, multilocus sequence typing (MLST), spa typing, PCR-detection of the leukotoxin encoding operon (LukI) and the Staphylococcus intermedius-exfoliative toxin (SIET) as well as antimicrobial resistance profiling by broth microdilution revealed that all five MRSP isolates from the dog and the single isolate from the owner were indistinguishable by any of the applied methods. All isolates were assigned to a certain strain, a multidrug-resistant MRSP belonging to sequence type (ST) 71, spa type (t)05, harbouring SCCmecIII as well as the genes encoding LukI and SIET. In this case, a number of reasons might have contributed to therapy failure and re-infection, respectively (e. g. contact to other MRSP-colonized dogs, contact to MRSP-colonized humans, refusal to clip the dog's fur). In addition, MRSP-contaminated objects or surfaces in the household, which were difficult to disinfect or simply not considered as a potential source of MRSP, might have served as a source of re-infection. These results envision the possibility of a dog-to-human transmission of MRSP and the relevance of this aspect as a potential source of re-infection in cases of bacterial-supported long-term skin disorders in canine patients. First cases of MRSP infections in humans have been described only recently. However, the general pathogenic potential of multidrug resistant MRSP in humans is unknown so far and needs further investigation.     

Cross-sectional study of antimicrobial-resistant bacteria in horses. Part 1: Prevalence of antimicrobial-resistant Escherichia coli and methicillin-resistant Staphylococcus aureus

Reasons for performing study: The increasing prevalence of antimicrobial‐resistant bacteria such as methicillin‐resistant Staphylococcus aureus (MRSA) and antimicrobial‐resistant Escherichia coli represents a significant problem. However, the carriage of such bacteria by horses in the UK has not been well characterised. Objectives: To estimate the prevalence of nasal carriage of MRSA and faecal carriage of antimicrobial‐resistant E. coli amongst horses in the general equine community of the mainland UK. Methods: A cross‐sectional study of horses recruited by 65 randomly selected equine veterinary practices was conducted, with nasal swabs and faecal samples collected. Faecal samples were cultured for antimicrobial‐resistant E. coli. Nasal swabs were cultured for staphylococcal species; methicillin‐resistant isolates identified as S. aureus were characterised by SCCmec and spa gene typing. Multilevel logistic regression models were used to calculate prevalence estimates with adjustment for clustering at practice and premises levels. Spatial variation in risk of antimicrobial resistance was also examined. Results: In total, 650 faecal samples and 678 nasal swabs were collected from 692 horses located on 525 premises. The prevalence of faecal carriage of E. coli with resistance to any antimicrobial was 69.5% (95% CI 65.9–73.1%) and the prevalence of extended‐spectrum β‐lactamase (ESBL)‐producing E. coli was 6.3% (95% CI 4.1–9.6%). The prevalence of nasal carriage of MRSA was 0.6% (95% CI 0.2–1.5%). Spatial analysis indicated variation across the UK for risk of carriage of resistant and multidrug‐resistant (resistant to more than 3 antimicrobial classes) E. coli. Conclusions and potential relevance: Carriage of MRSA by horses in the community appears rare, but the prevalence of antimicrobial‐resistant E. coli (including ESBL‐producing E. coli) is higher. A high prevalence of antimicrobial‐resistant bacteria could have significant health implications for the horse population of the UK.     

Determination of staphylococcal exotoxins, SCCmec types, and genetic relatedness of Staphylococcus intermedius group isolates from veterinary staff, companion animals, and hospital environments in Korea

The Staphylococcus (S.) intermedius group (SIG) has been a main research subject in recent years. S. pseudintermedius causes pyoderma and otitis in companion animals as well as foodborne diseases. To prevent SIG-associated infection and disease outbreaks, identification of both staphylococcal exotoxins and staphylococcal cassette chromosome mec (SCCmec) types among SIG isolates may be helpful. In this study, it was found that a single isolate (one out of 178 SIG isolates examined) harbored the canine enterotoxin SEC gene. However, the S. intermedius exfoliative toxin gene was found in 166 SIG isolates although the S. aureus-derived exfoliative toxin genes, such as eta, etb and etd, were not detected. SCCmec typing resulted in classifying one isolate as SCCmec type IV, 41 isolates as type V (including three S. intermedius isolates), and 10 isolates as non-classifiable. Genetic relatedness of all S. pseudintermedius isolates recovered from veterinary staff, companion animals, and hospital environments was determined by pulsed-field gel electrophoresis. Strains having the same band patterns were detected in S. pseudintermedius isolates collected at 13 and 18 months, suggesting possible colonization and/or expansion of a specific S. pseudintermedius strain in a veterinary hospital.     

Molecular characteristics of new clonal complexes of Staphylococcus pseudintermedius from clinically normal dogs

Background: High prevalence of methicillin resistance among clinical isolates of Staphylococcus pseudintermedius obtained from dogs was reported in Seoul metropolitan area, South Korea. However, no information on genetic lineage and clonal spread is currently available.

Objective: The aim is to identify the genetic diversity of methicillin-resistant or -susceptible S. pseudintermedius (MRSP and MSSP, respectively) from healthy dogs.

Animals and methods: From 119 healthy dogs, 29 isolates consisting of 20 MRSP and 9 MSSP were collected from June 2013 to February 2014. Phenotypic features, antibiogram, multilocus sequence type (MLST), Staphylococcal cassette chromosome mec (SCCmec) type and spa gene type were analyzed.

Results: MLST showed 24 sequence types (STs), including 20 new STs that were genetically distinct from the previous STs in other geographic areas. SCCmec typing revealed that all isolates had SCCmec type V, a predominant type in North America. spa gene typing was successful in only 13 isolates (10 MRSP and 3 MSSP) and revealed two known types (t02 and t06), as well as one novel type (t73).

Conclusion: Our cumulative data indicate the presence of various populations of S. pseudintermedius in clinically normal dogs in Seoul metropolitan area.     

Tandem repeat sequence analysis of staphylococcal protein A (spa) gene in methicillin-resistant Staphylococcus pseudintermedius

A putative staphylococcal protein A (spa) gene was discovered in the genome of Staphylococcus pseudintermedius and used for developing a species-specific spa typing protocol. Thirty-one clinical methicillin-resistant S. pseudintermedius (MRSP) isolates from dogs and cats in four countries were characterized by spa typing, pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome (SCCmec) typing. The results indicated the occurrence of two MRSP clones that acquired distinct SCCmec elements in Europe (t02, PFGE type A, SCCmec type III,) and California (t06, PFGE type B, SCCmec type V). Sequence analysis of mecA revealed the occurrence of four alleles (mecA1 to mecA4), which correlated with the geographical origin of the isolates and enabled discrimination of two distinct subtypes within the European clone. The newly developed spa typing method appeared to be a promising tool for easy and rapid typing of MRSP, either alone or in combination with SCCmec and mecA typing for fine-structure epidemiological analysis.     

Prevalence of canine methicillin resistant Staphylococcus pseudintermedius in a veterinary diagnostic laboratory in Italy

The overall prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) was 2% (10/590) among 590 canine specimens submitted to an Italian veterinary diagnostic laboratory during a two-month period, and 21% (10/48) among Staphylococcus intermedius group (SIG) isolates. All methicillin-resistant strains exhibited additional resistance to fluoroquinolones, gentamicin, lincosamides, tetracyclines, and potentiated sulfonamides, belonged predominantly to spa type t02 and harboured SCCmec type II–III cassette.     

Antimicrobial resistance studies in staphylococci and streptococci isolated from cows with mastitis in Argentina

Background Staphylococcus aureus and Streptococcus agalactiae are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. Bacteria isolated from infected animals show increasing antimicrobial resistance.ObjectivesThis study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci.MethodsIsolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCCmec type and spa type were detected by the polymerase chain reaction method.ResultsWe isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as S. aureus. Among the 154 CNS, 24.6% (n = 38) were resistant to penicillin, 14.9% (n = 23) to erythromycin, 17.5% (n = 27) to clindamycin, 6.5% (n = 10) to cefoxitin and oxacillin. Among the S. aureus isolates, 16.1% (n = 5) were resistant to penicillin, 3.2% (n = 1) to cefoxitin and oxacillin (MRSA). Six MR isolates (5 CNS and 1 MRSA) were positive to the mecA gene, and presented the SCCmec IVa. The MRSA strain presented the sequence type 83 and the spa type 002. Among the 28 streptococcal isolates, 14.3% (n = 4) were resistant to penicillin, 10.7% (n = 3) to erythromycin and 14.3% (n = 4) to clindamycin.ConclusionsThe present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.     

Antimicrobial resistance in Escherichia coli isolates from frugivorous (Eidolon helvum) and insectivorous (Nycteris hispida) bats in Southeast Nigeria,with detection of CTX-M-15 producing isolates

Thirty-five Escherichia coli isolates obtained from the liver, spleen and intestines of 180 frugivorous and insectivorous bats were investigated for antimicrobial resistance phenotypes/genotypes, prevalence of Extended-Spectrum beta-lactamase (ESBL) production, virulence gene detection and molecular typing. Eight (22.9 %) of the isolates were multidrug resistant (MDR). Two isolates were cefotaxime-resistant, ESBL-producers and harbored the bla_CTX-M-15 gene; they belonged to ST10184-D and ST2178-B1 lineages. tet(A) gene was detected in all tetracycline-resistant isolates while int1 (n = 8) and bla_TEM (n = 7) genes were also found. Thirty-three of the E. coli isolates were assigned to seven phylogenetic groups, with B1 (45.7 %) being predominant. Three isolates were enteropathogenic E. coli (EPEC) pathovars, containing the eae gene (with the variants gamma and iota), and lacking stx1/stx2 genes. Bats in Nigeria are possible reservoirs of potentially pathogenic MDR E. coli isolates which may be important in the ecology of antimicrobial resistance at the human-livestock-wildlife-environment interfaces. The study reinforces the importance of including wildlife in national antimicrobial resistance monitoring programmes.     

Dynamic of nasal colonization by methicillin-resistant Staphylococcus aureus ST398 and ST1 after mupirocin treatment in a family in close contact with pigs

Nasal colonization by methicillin-resistant Staphylococcus aureus (MRSA) was evaluated after a mupirocin treatment in a family previously colonized by MRSA sequence type ST398 and ST1, who lived close to a pig farm. Eight nasal samples were swabbed from each of the four family members on different moments after mupirocin treatment. The efficacy of treatment was low in those family members who worked in the farm, and higher in the remaining two family members with sporadic contact with pigs. In addition, nasal and skin swabs from randomly selected pigs of the farm were taken. MRSA were detected in 33% of pigs tested. All MRSA isolates obtained were characterized by Staphylococcal-Cassette-Chromosome mec (SCCmec) determination, Multilocus-Sequence-Typing (MLST), spa- and agr-typing, Pulsed-field-gel-electrophoresis (PFGE), antimicrobial susceptibility, detection of antimicrobial resistance genes, and toxin gene profiling. Spa-types t011, t1255 and t1197 were detected in humans and animals, with indistinguishable PFGE patterns, suggesting animal to human MRSA transmission. Each spa-type was ascribed to a specific pulsotype. Spa-types t127 and t108 were only detected in MRSA isolates obtained from humans, and t012 only in those from animals. MRSA ST1-t127 isolates and some ST398-t011 and ST398-t1197 isolates presented a multiantimicrobial-resistance phenotype. None of them harbored lukF/lukS, tst, eta and etb virulence genes. This study showed that the efficacy of nasal MRSA decolonization in healthy people with very close contact with pigs is especially low.     

中国部分地区犬源伪中间葡萄球菌的流行特征分析

旨在调查犬源伪中间葡萄球菌的耐药性和分子特征，本研究自2017年11月—2019年4月收集601份送检至中国农业大学动物医院检验科和第三方检测机构的犬源临床样本，分离鉴定伪中间葡萄球菌；采用琼脂稀释法检测伪中间葡萄球菌对14种抗菌药物的敏感性；所有分离菌株均进行全基因组测序（WGS），并从WGS结果中获取耐药基因、多位点序列分型（ST）和葡萄球菌染色体基因盒（SCCmec）分型。结果显示，共分离到75株伪中间葡萄球菌（分离率为12.5%），其中包括42株（56%）耐甲氧西林伪中间葡萄球菌（MRSP）和33株（44%）甲氧西林敏感伪中间葡萄球菌（MSSP）；所有菌株均对青霉素、阿奇霉素、克林霉素、多西环素、环丙沙星、恩诺沙星、苯唑西林和氯霉素高度耐药，对利奈唑胺、万古霉素、阿米卡星和利福平敏感，多重耐药率达90.7%；所有MRSP均具有多重耐药性；75株伪中间葡萄球菌中检测到19种耐药基因，blaZ和aac（6'）-aph（2″）检出率最高，均为92%（69/75）；共发现70种ST型，54种为新ST型，无优势ST型；23株（54.7%） MRSP为SCCmec V型。综上表明，犬源伪中间葡萄球菌存在严重的多重耐药性；MRSP和MSSP均具有较大的遗传多样性。     

Molecular Epidemiology and Antimicrobial Resistance Mechanisms of Methicillin‐Resistant Staphylococcus aureus Isolated from Bovine Milk

The aim of this study was to identify methicillin‐resistant Staphylococcus aureus (MRSA) strains gathered from 2002 to 2006 from milk samples in Aydin region in Turkey. Among 93 S. aureus strains isolated from bovine milk with mastitis, 16 were resistant to methicillin. Methicillin‐resistant S. aureus strains were studied further for their staphylococcal cassette chromosome mec (SCCmec) types, pulsotypes, spa and MLST types, antimicrobial susceptibilities, mechanisms of resistance and presence of Panton–Valentine leucocidin (PVL) toxin gene. The MRSA strains were multi‐drug resistant. The susceptibility rates to antimicrobials tested were 0%, 0%, 0%, 0%, 6.25%, 16.25% and 56.25% for erythromycin, clindamycin, chloramphenicol, gentamicin, tetracyclin, ciprofloxacin and vancomycin, respectively. All tetracycline and gentamicin resistant strains carried tet(M) and aac(6)‐aph(2) gene, respectively. Among macrolide‐resistant isolates, nine had erm(A), and seven had both erm(A) and erm(B) genes. The molecular characterization by pulsed‐field gel electrophoresis showed presence of three pulsotypes with their variants. The pulsotype B strains were type IV with SCCmec typing, and representative of pulsotype B was t190 by spa typing and ST8 by MLST typing. The strains with pulsotype A and C were SCCmec III, and representative of these pulsotypes was t030 by spa typing. The MLST type of pulsotype A was ST239 and pulsotype C was one allele variant of ST239. None of the isolates harboured the PVL gene. Presence of hospital‐related MRSA strains may indicate transmission of these strains between human and animals. In case of clonal spread beside the infected animals’ treatment of MRSA carrier, farm workers should also be considered. Hygienic measures and rational antibiotic use may avoid resistance selection, clonal dissemination of resistant strains and decrease losses because of mastitis in dairy herds.