Antimicrobial Susceptibilities of Erysipelothrix rhusiopathiae Isolated from Pigs with Swine Erysipelas in Japan, 1988–1998

The susceptibility to 21 antimicrobial agents of 214 strains of Erysipelothrix rhusiopathiae isolated from pigs affected with swine erysipelas in Japan between 1988 and 1998 was determined. Ampicillin, cloxacillin, benzylpenicillin, ceftiofur, tylosin, enrofloxacin and danofloxacin were the most active agents [minimum inhibitory concentrations (MICs); ≤ 0.025?0.78 μg/ml], followed by cefazolin, virginiamycin, tiamulin, chloramphenicol, florphenicol and oxolinic acid (MICs; 0.1–25 μg/ml). Activity was poor or absent with kanamycin and sulfadimethoxine. Strains resistant to dihydrostreptomycin, erythromycin, clindamycin, lincomycin, oxytetracycline and doxycycline were detected. The susceptibilities to dihydrostreptomycin and oxytetracycline tended to decrease. Investigation of the differences in antimicrobial susceptibility of the 214 strains according to their serotypes, sources, isolation years and regions, showed that the strains resistant to dihydrostreptomycin were most frequently found in the strains of serotype 1a and in strains from septicaemic cases. Strains resistant to oxytetracycline were detected in all serotypes and all sources, and most of the strains resistant to erythromycin were detected in the strains of serotype 2. The frequency of strains resistant to dihydrostreptomycin gradually increased from 1988 to 1996, but then decreased between 1997 and 1998. The frequency of strains resistant to oxytetracycline was remained more than 38% from 1988 to 1998. It was suggested that the strains resistant to dihydrostreptomycin and oxytetracycline were distributed over almost all districts of Japan.     

Antimicrobial susceptibilities of Listeria monocytogenes isolated in Japan

The antimicrobial susceptibility of 201 Listeria monocytogenes isolates from foods, environments, animals and human patients in Japan was determined. All isolates were susceptible to ampicillin, the first choice of drug for listeriosis treatment, chloramphenicol, dihydrostreptomycin, erythromycin, enrofloxacin, gentamicin, kanamycin, lincomycin, nosiheptide, salinomycin, vancomycin, and virginiamycin. A human strain was resistant to oxytetracycline. The Minimum Inhibitory Concentration (MIC) for 50% of the strains and the MIC for 90% of the strains were comparable in all the isolates. This is the first investigation to compare antibiotic resistances between isolates from foods and isolates from human patients in Japan. The result showed that most of the isolates were susceptible to antibiotics used in this study.     

Minimum inhibitory concentrations of 20 antimicrobial agents against Staphylococcus aureus isolated from bovine intramammary infections in Japan

Minimum inhibitory concentrations (MICs) of 20 antimicrobial agents were determined against 51 isolates of Staphylococcus aureus from bovine intramammary infections. Fourteen (27.4%) isolates were resistant to benzylpenicillin, but none of the isolates was resistant to cloxacillin, nafcillin, or cephems. Among aminoglycosides, gentamicin was the most active, with an MIC50 of 0.2 microg/ml, followed by kanamycin, with an MIC50 of 0.78 microg/ml. Five isolates (9.8%) were resistant to dihydrostreptomycin, three isolates (5.9%) to kanamycin and two isolates (3.9%) to gentamicin. Resistance to erythromycin was observed in two isolates (3.9%). Tylosin was less active than erythromycin, with MIC50s of 1.56 microg/ml versus 0.39 microg/ml, but none of the isolates was resistant to this antibiotic. Oxytetracycline MICs were situated in the range of 0.39-1.56 microg/ml for 48 susceptible isolates. Although 19 (37.3%) isolates were resistant to one or more antimicrobial agents, a single resistance pattern was most frequent: benzylpenicillin (12 isolates), dihydrostreptomycin (two isolates) and kanamycin (one isolate). There were no isolates resistant to antimicrobial agents such as methicillin, lincomycin, clindamycin, chloramphenicol, florfenicol and virginiamycin, which have not been approved for use in cattle husbandry in Japan.     

Antimicrobial resistance in streptococcal species isolated from bovine mammary glands

Streptococcal species isolated from dairy cows with clinical mastitis were obtained from mastitis research workers in Florida, Louisiana, New York, Vermont, Washington, and West Virginia. Seventy-one streptococcal isolates were tested, including 39 strains of Streptococcus agalactiae, 21 strains of S dysgalactiae, and 11 strains of S uberis. The minimal inhibitory concentration of erythromycin, lincomycin, oxytetracycline, penicillin, spectinomycin, streptomycin, and tetracycline was determined for each isolate. Differences were not detected among strains with respect to geographic origin. None of the strains was resistant to penicillin. Lincomycin was the next most effective antimicrobial, with only 2 resistant strains of each streptococcal species. There were no differences among the streptococcal species with respect to resistance to either penicillin or lincomycin. Streptococcus uberis was more likely to be resistant to erythromycin than were S agalactiae and S dysgalactiae (P less than 0.02). Streptococcus agalactiae and S uberis had similar distributions for resistance to oxytetracycline, tetracycline, spectinomycin, and streptomycin. Strains of S dysgalactiae were more likely to have intermediate resistance to oxytetracycline and streptomycin than were strains of S agalactiae and S uberis, which were highly resistant to oxytetracycline and streptomycin (P less than 0.001). Differences were not detected among the streptococcal species with respect to resistance to spectinomycin. Resistance to multiple antimicrobials was observed in all streptococcal species tested. Although S dysgalactiae appeared to have a greater percentage of strains (73%) that were resistant to multiple antimicrobials than did S agalactiae (31%) or S uberis (45%), differences were not statistically significant.     

Antimicrobial susceptibility of clinical strains of Streptococcus suis isolated from pigs in Spain

The antimicrobial susceptibility of 151 clinical Streptococcus suis strains isolated from diseased pigs in Spain was determined by a microdilution method. Isolates were mostly susceptible to beta-lactam antimicrobials, aminoglycosides, enrofloxacin, novobiocin and spectinomycin. More than 87% of the S. suis isolates were resistant to tetracyclines, sulphonamides, macrolides and clindamycin. Strains of serotype 9 were significantly more resistant than strains of serotype 2 (P<0.05) to tylosin (94% versus 77%) and clindamycin (94% versus 64%). Eighty-seven percent of the S. suis isolates were resistant to at least four antimicrobials and nine isolates (6%) were resistant to at least six antimicrobials. The most frequently identified multidrug pattern involved resistance against tetracyclines, sulphonamides, macrolides and lincosamides, with 69% of the isolates exhibiting this resistotype. Fifteen out of the 22 strains of serotype 2 (68.2%), and 84 out of the 98 of the strains of serotype 9 (85.7%) exhibited this resistotype, indicating its widespread distribution among the strains of the two most frequently isolated serotypes.     

Antimicrobial drug susceptibility of Staphylococcus intermedius clinical isolates from canine pyoderma

A total of 50 Staphylococcus intermedius strains isolated in France from canine pyodermas in 2002 were investigated for their susceptibility to various antimicrobial drugs. Antimicrobial susceptibility was assessed using a 2-fold serial dilution method in Mueller-Hinton agar, and the minimal inhibitory concentrations (MICs) were determined. About 62% of the 50 strains tested were producers of beta-lactamase and categorized as penicillin-resistant. About 26% demonstrated resistance to sulphonamides, 46% to oxytetracycline, 30% to chloramphenicol, 28% to streptomycin, kanamycin, neomycin or erythromycin, 22% to clindamycin, 6% to doxycycline, 2% to gentamicin, enrofloxacin, marbofloxacin or pradofloxacin. Acquired resistance was not observed to a clavulanic acid-amoxicillin combination, oxacillin, cephalosporins (cephalexin, ceftiofur and cefquinome), trimethoprim, a sulphamethoxazole-trimethoprim combination and florfenicol. About 42% were simultaneously resistant to three or more antimicrobial classes (multiresistance). All isolates with acquired resistance to erythromycin were also resistant to streptomycin and neomycin/kanamycin. About 22% of isolates exhibited cross-resistance between erythromycin and clindamycin and all clindamycin-resistant isolates also exhibited resistance to erythromycin. Resistance to penicillin, oxytetracycline and chloramphenicol was also positively associated with resistance to erythromycin and streptomycin.     

猪传染性胸膜肺炎放线杆菌的鉴定和耐药性研究

猪传染性胸膜肺炎是由猪传染性胸膜肺炎放线杆菌(Actinobacillus pleuralpneumoniae,APP)引起的一种高度传染性呼吸道疾病,临床上准确鉴定该病原菌并合理选择抗生素施药十分重要。研究比较了应用传统方法、PCR方法和MALDI TOF方法鉴定45株临床APP,并比较了三种优势血清型的毒力表型,最后测定了其对临床34种常见抗生素的MIC。结果发现MALDI TOF微生物学鉴定方法具有快速、准确的优势;临床菌株血清型主要包括3型（20株）、1型（13株）、7型（7株）,其他血清型菌株5株,其中1型毒力最强;APP对罗红霉素、头孢噻呋、恩诺沙星、氨苄西林等高度敏感,对四环素、土霉素等耐药率较高。研究为临床快速鉴定APP和合理选择用药提供了参考依据,为APP临床耐药折点的制定奠定了基础。     

Antimicrobial resistance in Salmonella isolates from apparently healthy food-producing animal from 2000 to 2003: the first stage of Japanese veterinary antimicrobial resistance monitoring (JVARM)

Antimicrobial susceptibility of 183 Salmonella isolates from apparently healthy food-producing animals obtained during the period from 2000 to 2003 throughout Japan was examined. Of 29 serovars identified, Salmonella Infantis (37.7%) was the most prevalent, followed by S. Typhimurium (19.7%). Salmonella bacteria resistant to dihydrostreptomycin (77.6%) were about 10% more prevalent than those resistant to oxytetracycline (67.8%), though the nation-level veterinary use of tetracycline antibiotics is much greater than that of streptomycin in Japan. In seventeen isolates (9.3%) resistant to nalidixic acid, single point mutations were detected at 84 or 87 in the quinolone resistance-determining region of the gyrA gene.     

Antimicrobial susceptibility of Arcanobacterium pyogenes isolated from cattle and pigs

The minimum inhibitory concentrations (MICs) of 18 antimicrobial agents were determined for 49 Arcanobacterium pyogenes isolates (42 bovine isolates and 7 porcine isolates). Benzylpenicillin and ampicillin were the most active antibiotics, with MIC ranges of < or = 0.0125-0.05 microgram/ml for both bovine and porcine isolates. All isolates were susceptible to penicillins and cephems. MICs for 90% of the isolates of dihydrostreptomycin, gentamicin and oxytetracycline for bovine isolates were > 100 micrograms/ml, 1.56 micrograms/ml and 25 micrograms/ml, respectively. More resistance to dihydrostreptomycin appeared among porcine isolates (85.7%) than among bovine isolates (52.4%). Resistance to gentamicin occurred in only 3 (7.1%) of the bovine isolates. Resistance to oxytetracycline also appeared more frequent among porcine isolates (85.7%) than among bovine isolates (57.1%). All bovine isolates were susceptible to erythromycin, tilmocosin and lincomycin, but two porcine isolates (28.6%) were simultaneously resistant to these antibiotics. Tiamulin was as active as tilmicosin, with an MIC for 50% of the isolates (MIC50) of 0.05 microgram/ml for both bovine and porcine isolates. The MIC50s of chloramphenicol and its derivatives florfenicol and thiamphenicol were all 1.56 micrograms/ml. The fluoroquinolones enrofloxacin and ofloxacin were not so active as penicillins and macrolides, with MIC50s of 0.78 microgram/ml and 1.56 micrograms/ml, respectively, for both bovine and porcine isolates.     

Serotypes and antimicrobial susceptibility of Pseudomonas aeruginosa strains isolated from diseased dogs

Strains of Pseudomonas aeruginosa isolated from diseased dogs in Tokyo area during 1983 through 1986 were serotyped and assayed for antimicrobial susceptibility to obtain an epizootiological aspect of canine P. aeruginosa infection. Major sources of specimens were ear and nasal discharges and urine. The results of O-antigen typing using a monoclonal antibody kit showed that the most predominant serotype was type M. Types G and B were also major serotypes. In a yearly distribution of serotypes, type I was almost limited in 1986, and was isolated mainly from surgical wounds, which showed an episode of nosocomial infection, whereas that of type M or B was dispersed during 4 years from 1983 to 1986. As a result of antimicrobial susceptibility test, most canine strains were considered to be susceptible to 4 drugs, which were commonly used in both human and veterinary clinics, in contrast to human isolates.     

Antimicrobial susceptibility of Escherichia coli isolates from wild mice in a forest of a natural park in Hokkaido, Japan

To reveal the antimicrobial susceptibilities of Escherichia coli isolates from wild mice, 81 E. coli isolates were obtained from 109 voles (Clethrionomys spp.), 52 large Japanese field mice (Apodemus speciosus) and 19 small Japanese field mice (A. argenteus) captured in a forest of a natural park in Hokkaido, Japan. Seventy-eight of the 81 E. coli isolates were susceptible to all 10 antimicrobial agents tested. One E. coli isolate was resistant to ampicillin, dihydrostreptomycin, kanamycin, chloramphenicol and oxytetracycline. Two isolates were resistant to oxytetracycline. A low prevalence of antimicrobial resistance was maintained among wild mice that inhabited the forest.     

Antimicrobial susceptibility of Mannheimia haemolytica isolates from cattle in Japan from 2001 to 2002

A total of 27 clinical isolates of Mannheimia haemolytica from cattle in Japan from 2001 to 2002 were examined for antimicrobial susceptibility to 25 antimicrobial agents. The minimum inhibitory concentrations of 25 different antimicrobials were determined by an agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards. Of the 27 isolates, seven isolates (26.9%) were resistant to at least one of the 25 drugs and resistance rates ranged from 3.7 to 18.5%. Resistance rates to dihydrostreptomycin (18.5%), oxytetracycline (11.1%), and doxycycline (11.1%) were relatively high and those to the remaining drugs were less than 10%.     

Minimal inhibitory concentrations of antimicrobial agents against Actinobacillus pleuropneumoniae.

Forty-five isolates of Actinobacillus pleuropneumoniae were tested for susceptibility to 12 antimicrobial agents using a microdilution method for the minimal inhibitory concentration determinations. These results confirmed the high prevalence of A. pleuropneumoniae strains resistant to antibiotics as reported earlier using the disc diffusion method (Kirby-Bauer method). While 36% of the isolates were resistant to the penicillins, 47% were resistant to chloramphenicol and 68% were resistant to tetracycline. Minimal inhibitory concentrations for the resistant isolates were approximately 32 times higher than those for the susceptible isolates to the above antibacterial agents. The isolates were in general weakly susceptible or resistant to spectinomycin, lincomycin, tiamulin and spiramycin whereas most of them were susceptible to gentamicin, trimethoprim and erythromycin. The susceptibility pattern was similar throughout the 1980 to 1984 period. The 14 serotype 5 isolates were more resistant to tetracycline but less resistant to chloramphenicol and the penicillins than the 28 serotype 1 isolates.     

Evaluation of changes in antimicrobial susceptibility patterns of Pasteurella multocida subsp multocida isolates from pigs in Spain in 1987-1988 and 2003-2004

OBJECTIVE: To determine the susceptibility of strains of Pasteurella multocida subsp multocida isolated from lung specimens of pigs with pneumonia to 20 antimicrobials and to evaluate the emergence of resistance to those antimicrobials in Spain during the past 2 decades. SAMPLE POPULATION: 63 isolates recovered from 1987 to 1988 and 132 isolates recovered from 2003 to 2004. PROCEDURE: A broth microdilution method was used to determine minimal inhibitory concentration (MIC) range and values for MIC50 and MIC90. Resistance of a strain to an antimicrobial agent was determined by use of the breakpoint value when available. RESULTS: Isolates were generally susceptible to penicillin, ampicillin, ceftiofur, gentamicin, apramycin, neomycin, spectinomycin, chlortetracycline, erythromycin, tilmicosin, enrofloxacin, and florfenicol, and most isolates were resistant to clindamycin, tylosin tartrate, and tiamulin regardless of the time period. A substantial increase in resistance to sulfa-chlorpiridazine, sulfadimethoxine, sulfathiazole, and trimethoprim-sulfamethoxazole was observed, and a minor increase in resistance to oxytetracycline was also detected. Several multiresistance patterns were observed, most frequently among isolates recovered in the 2003 to 2004 interval. CONCLUSIONS AND CLINICAL RELEVANCE: Ceftiofur, florfenicol, and enrofloxacin are recommended for treatment of infections caused by P multocida subsp multocida in Spain. Increased frequency of resistance to oxytetracycline and sulfonamide drugs may be a contraindication for their use.     

Plasmid profile analysis of bovine isolates of Pasteurella haemolytica

Pasteurella haemolytica isolates, obtained from cattle with respiratory tract disease, were characterized as to serotype, antimicrobial susceptibility, and plasmid content. Strains isolated from 2 groups of cattle were compared. Remarkable similarity was seen in the plasmid profiles of isolates of the same serotype. In contrast, isolates of 2 different serotypes had totally different plasmid profiles.     

Susceptibility of Arcanobacterium pyogenes from different sources to tetracycline, macrolide and lincosamide antimicrobial agents

Chlortetracycline, oxytetracycline, and the macrolide, tylosin, are extensively used for growth promotion and disease prophylaxis in the cattle and swine industries in the US. Arcanobacterium pyogenes, a common inhabitant of the mucosal surfaces of cattle and swine, is also a pathogen associated with a variety of infections in these animals. A broth microdilution technique was used to determine the antimicrobial susceptibility of 48 A. pyogenes isolates to macrolides, lincosamides and tetracyclines. The MIC50 and MIC90 for chlortetracycline were 0.12 and 8 mg/l, respectively. Similarly, the MIC50 and MIC90 for oxytetracycline were 0.25 and 8 mg/l, while the MIC50 and MIC90 for tetracycline were 0.25 and 16 mg/l, respectively. The MIC50 and the MIC90 were < or = 0.06 and >64 mg/l, respectively, for erythromycin, tylosin and clindamycin. This resistance pattern indicated that some of these A. pyogenes isolates may carry an MLS(B) resistance determinant. A. pyogenes isolates (12.5%) were resistant to erythromycin, and this percentage doubled when MICs were performed following induction with erythromycin. Of the 48 A. pyogenes isolates, 25 and 41.7% were resistant to MLS(B) antimicrobial agents and the tetracycline derivatives, respectively. MLS(B) resistance was present in 22.2 and 35.3% of A. pyogenes isolates of bovine (n=27) or porcine (n=17) origin. In contrast, 70.6% of porcine isolates were resistant to the tetracyclines, compared with 25.9% of bovine isolates. These data suggest that a large proportion of A. pyogenes field isolates may be resistant to these commonly used antimicrobial agents.     

Trends in the resistance to antimicrobial agents of Streptococcus suis isolates from Denmark and Sweden

This study was conducted to determine the MIC values of historical and contemporary Streptoccocus suis (serotypes 2 and 7) from Denmark and S. suis (serotype 2) from Sweden. A total of 52 isolates originating from 1967 through 1981 and 156 isolates from 1992 through 1997 in Denmark and 13 isolates from Sweden were examined for their MICs against 20 different antimicrobial agents. Most antimicrobials were active against most isolates. A frequent occurrence of resistance to sulphamethoxazole was observed, with most resistance among historic isolates of serotype 7 and least resistance among isolates from Sweden. A large number of the isolates was resistant to macrolides. However, all historic serotype 2 isolates from Denmark were susceptible, whereas 20.4% of the contemporary isolates were resistant. Among serotype 7 isolates 23.3% of the historic isolates were resistant to macrolides, whereas resistance was found in 44.8% of the contemporary isolates. All isolates from Sweden were susceptible to macrolides. Time-associated frequency of resistance to tetracycline was also found. Only a single historic isolate of serotype 2 was resistant to tetracycline, whereas 43.9% of the contemporary serotype 2 isolates and 15.5% of the contemporary serotype 7 isolates were resistant. Only one (7.7%) of the isolates from Sweden was resistant. The differences in resistance between historic and contemporary isolates from Denmark were statistically significant. This study demonstrated a significant serotype-associated difference in the susceptibility to macrolides and tetracycline and demonstrated that an increase in resistance among S. suis isolates has taken place during the last 15 years to the two most commonly used antimicrobial agents (tylosin and tetracycline) in pig production in Denmark.     

Antibiotic Resistance in Salmonella Isolated from Tegus (Tupinambis spp.)

In recent years, an increase in human clinical cases of reptile-associated salmonellosis has been identified, and it has been attributed to the increased popularity of these animals as pets. Limited information is available regarding the distribution of Salmonella spp. serotypes in different reptile species and the antimicrobial resistance patterns of Salmonella spp. isolated from pet reptiles. This article describes the prevalence of Salmonella spp., distribution of serotypes, and antibiotic susceptibility patterns from isolates cultured from cloacal swabs obtained from 14 tegu lizards (Tupinambis spp.). Eighteen strains of Salmonella belonging to different serotypes were obtained from the 14 tegu lizards. Of the 18 Salmonella spp. isolates, 8 (44.4%) were from Salmonella subspecies I, with a majority of isolates belonging to the Eastbourne serotype (3 strains), Nottingham serotype (2 strains), and Brancaster serotype (2 strains), and only 1 belonging to the Apapa serotype. Less common serotypes were detected in 5 isolates, including 2 each belonging to Salmonella subspecies II and IIIb, respectively, and 1 to Salmonella subspecies IIIa. The serotype of 5 other Salmonella isolates could not be determined. All 18 isolates were resistant to at least 6 of the antimicrobial drugs tested. These results confirm the potential zoonotic risk from handling reptiles, suggesting that measures to educate the reptile-owning public are necessary.     

Antimicrobial susceptibility of udder pathogens isolated from dairy herds in the west littoral region of Uruguay

A total of 522 strains belonging to streptococci, enterococci and staphylococci isolated from sub-clinical and clinical cases of bovine mastitis from the west littoral region of Uruguay were analysed for their susceptibility to several antimicrobial agents. The susceptibility patterns were studied by agar disk diffusion methods (ADDM) and broth micro-dilution to determine the minimum inhibitory concentration (MIC). The concentration that inhibits 90% (MIC90) of the analysed strains reported in micrograms per millilitre, for Staphylococcus aureus were > 8, 8, < or = 0.5, < or = 4, < or = 1, < or = 0.5, > 64, < or = 0.25, 0.5, < or = 1 and < or = 1 to penicillin, ampicillin, oxacillin, cephalotin, gentamicin, erythromycin, oxitetracycline, enrofloxacin, trimethoprim/sulfamethoxazole, neomycin, and clindamycin, respectively. Coagulase-negative staphylococci (CNS) had different values for penicillin (4) and ampicillin (2), while the other antimicrobial agents had the same MIC90 values as reported for S. aureus. The MIC90 values for streptococci were 0.12, 0.25, < or = 4, 16, < or = 0.25, 0.5, 0.25 for penicillin, ampicillin, cephalotin, gentamicin, erythromycin, oxytetracycline and trimethoprim-sulfamethoxazole, whereas MIC90 for enterococci were 4, 4, 4, < or = 0.5, 2, > 8 for penicillin, ampicillin, gentamicin, erythromycin, oxytetracycline and trimethoprim-sulfamethoxazole, respectively. Of 336 strains of S. aureus, 160 (47.6%) were resistant to penicillin. For 41 CNS strains, 10 (27%) presented penicillin-resistance. All the streptococcal strains were susceptible to penicillin, while 3 (7%) of the 43 enteroccocal strains were resistant. Non significant statistical differences were found between the results obtained by ADDM and broth micro-dilution for classifying bacterial isolates as susceptible or resistant according to the National Committee of Clinical Laboratory Standards.     

Prevalence and mechanism of antimicrobial resistance in Staphylococcus aureus isolates from diseased cattle, swine and chickens in Japan

Antimicrobial administration is essential for the control and treatment of diseases in animals, but the emergence and prevalence of antimicrobial-resistant Staphylococcus aureus is a significant concern during animal production. Here we investigated the antimicrobial susceptibility of S. aureus from diseased food-producing animals and molecularly characterized the methicillin-resistant and fluoroquinolone-resistant isolates. A total of 290 S. aureus isolates obtained from cattle (n=246), swine (n=16), and chickens (n=28) between 2003 and 2009 were examined for antimicrobial susceptibility against 9 antimicrobials using an agar dilution method. Resistance to penicillin (PC) was most frequently found (24.8%), followed by oxytetracycline (OTC, 10.0%), dihydrostreptomycin (4.1%), erythromycin (EM, 3.1%), enrofloxacin (ERFX, 2.1%), and kanamycin (1.7%). The PC resistance rate was significantly higher in swine than in cattle (P<0.01) and chickens (P<0.01). The resistance rates to OTC, EM and ERFX were significantly higher in swine and chickens than in cattle (P<0.05). Methicillin-resistant S. aureus (MRSA) was recovered from milk derived from a cow with mastitis in 2003; sequence type 8, SCCmec type IV and spa type t024. In the six ERFX-resistant strains isolated after 2003, amino acid substitutions in ParC with/without GyrA were detected. As the prevalence of MRSA and FQ-resistant S. aureus in the animals should be noticed, continuous monitoring is necessary to control resistance to clinically important antimicrobials in S. aureus from food-producing animals.