Antimicrobial resistance and multi-drug resistance patterns have been carried out on total of 210 isolated of Salmonella spp. and pathogenic E. coli isolated from food poisoning patients on January through December 2012 in Incheon, Korea. The highest percentage of antibiotics resistance was found to the following antimicrobial agents: tetracycline 43.8%, ampicillin 34.8%, nalidixic acid 23.8%, sulfamethoxazole/trimethoprim and chloramphenicol 12.4%, and ampicillin/sulbactam 11.4%. The highest percentage of resistance was 37.5% to ampicillin for Salmonella spp. and 59.0% to tetracycline for pathogenic E. coli. Overall the multidrug resistance rates of 1 drug was 26.2%, 2 drugs 9.0%, 3 drugs 9.5%, 4 drugs 7.1%, and 5 or more drugs 12.46%. The multi-drug (MDR) strains to four or more antimicrobial agents among the resistant organisms were quite high: 15.9% and 22.1% for Salmonella spp. and pathogenic E. coli, respectively. The study implies that limitation of unnecessary medication use is pertinent in order to maintaining the efficacy of drugs.

Saliva from the oral cavity was collected from 129 patients with periodontitis and 54 Staphylococcus aureus isolates were isolated from these samples. The S. aureus isolates were tested for their resistance patterns against 15 antibiotics using the disc diffusion method. The percentage of S. aureus isolates resistant to ampicillin was the highest (92.6%). In addition, the percentage of S. aureus isolates resistant to penicillin, oxacillin, cefotetan, cefepime and erythromycin was 90.7%, 11.1%, 11.1%, 9.3% and 5.6%, respectively. However, S. aureus isolates were susceptible to gentamycin, clindamycin, trimethoprim/sulfamethoxazole and vancomycin. 96.3% of S. aureus isolates were resistant to antibiotics. Among them, the percentage of two antibiotic-resistant S. aureus isolates was 74.1%, the percentage of one antibiotic-resistant S. aureus isolates was 5.6%, the percentage of three antibiotic-resistant S. aureus isolates was 3.7% and the percentage of S. aureus isolates resistant to more than 4 antibiotics was 13%. The most common multiple antimicrobial resistance pattern was AM-P. Furthermore, the percentage of methicillin-resistant S. aureus isolates was 11.1% and they were resistant to more than 3 antibiotics.

To determine current rate of antimicrobial resistance, a total of 236 isolates from milk samples of dairy cattle with mastitis in Korea during 2010-2011 were examined against 12 antimicrobials using disc diffusion method: 67 Staphylococcus aureus, 74 coagulase-negative Staphylococcus spp. (CNS), and 95 Escherichia coli isolates. The isolates examined in this study were submitted by Local Veterinary Service Laboratories located in 13 provinces and metropolitan cities nationwide. The highest rates of resistance among S. aureus isolates were against ampicillin (56.7%) and penicillin (56.7%), followed by kanamycin (11.9%). All S. aureus isolates were sensitive to lincomycin, amikacin, and cephalothin. Only one isolate showed resistance to tetracycline and oxacillin, respectively. Less than 10% of the S. aureus isolates presented resistance to erythromycin, neomycin, and gentamicin. Among CNS isolates, the most frequently observed resistance was to lincomycin (44.5%), followed by penicillin (28.3%), ampicillin (18.9%), tetracycline (17.5%), kanamycin (13.5%), and erythromycin (9.4%). All or most of the CNS isolates were sensitive to cephalothin, amikacin, neomycin, and gentamicin. The highest rate of resistance among E. coli isolates was against tetracycline (26.3%), followed by streptomycin (21%), neomycin (15%), kanamycin (12.6%), and gentamicin (10.5%). Amikacin was the only antimicrobial to which no E. coli isolates showed resistance. Around 10% of the S. aureus isolates and 15% of the CNS isolates showed resistance against three or more antimicrobials simultaneously, while more than 30% of the E. coli isolates did.

Salmonellosis constitutes an important public health problem in both developing and developed countries, including Korea. The aims of present study were to investigate the serovar and antimicrobial resistance of Salmonella isolated from food animals and animal products in slaughterhouses and farms. A total of 323 Salmonella were isolated from food animals (n=277) and meats (n=46) during 2010. Of the isolates, 21 different serovars were identified. The predominant serovars were S. Rissen (35%) and S. Montevideo (24.3) in healthy pigs, while S. Enteritidis (25.5%) in healthy chicken. S. Typhimurium (88.8%) was predominant in disease pigs, while S. Gallinarum (29.2%) and S. Montevideo (26.9%) were in diseased chickens. Among meat samples, S. Typhimurium (57.1%) was the most common serovar in pork but S. Enteritidis (38.7%) and S. Montevideo(32.3%) were in chikcen meats. Analysis of antimicrobial resistance patterns revealed that 20.7% of the isolates were sensitive to all the 15 drugs tested. The isolates were frequently resistant to nalidixic acid (47.7%), tetracycline (38.4%), streptomycin (33.7%), and ampicillin (32.8%). The resistance to quinolone and 3rd generation cephalosporins was higher in chicken and chicken meat isolates. Of the 323 isolates, 174 (53.9%) were resistant to one or more CLSI subclass, and 117 (36.2%) showed multiple-resistance. Our findings showed that multiple resistant Salmonella organism are widespread in animals and animal products in Korea. To prevent the transmission or exposure for consumers of antimicrobial resistant Salmonella, policies and guidelines aiming at prudential use of critical antimicrobials for humans are needed.

Campylobacterosis is the most common food borne bacterial disease in many countries. Food animals and animal products are considered to be the reservoir of the Campylobacter species. The aim of this study was to investigate the antimicrobial resistance of Campylobacter spp. from food animals and raw meats in slaughterhouses. A total of 90 Campylobacter jejuni (C. jejuni) and 127 Campylobacter coli (C. coli) were isolated, for which antimicrobial susceptibility was examined using broth dilution method. Resistance to macrolide antimicrobials was higher among C. coli isolates than among C. jejuni. Among both C. jejuni and C. coli isolates, the most frequently observed resistance was to nalidixic acid, ciprofloxacin, and tetracycline. No erythromycin resistance was observed among C. jejuni isolates from cattle, pig and beef. However, 28.3% (n=13) and 25% (n=3) of C. coli isolates from pigs and pork showed resistance to erythromycin, respectively. The predominant profile of multiple resistance among C. jejuni and C. coli isolates was ciprofloxacin/tetracycline/nalidixic acid resistance (46.7%) and ciprofloxacin/nalidixic acid resistance (31.5%), respectively. This finding has important implication for food safety and public health.

Staphylococcus aureus is an important food-borne pathogen, which is present on the skin and mucosa of animals. Some of the S. aureus strains are causative agent of food poisoning syndrome. The aim of this study was to investigate the antimicrobial resistance of S. aureus isolates from raw meats in slaughterhouses during 2010. From 17,874 raw meat samples tested, a total of 190 S. aureus were isolated, for which antimicrobial susceptibility to 17 agents was examined using broth dilution method. Among isolates from beef, chicken and pork, 20 (51.3%), 20 (24.7%) and 9 (12.9%) were sensitive to all antimicrobials tested, respectively. Isolates from pork and chicken meats showed much higher resistance, compared to isolates from beef. Penicillin resistance was the most frequent among isolates from beef (35.3%) and pork (75.7%), while tetracycline resistance was among those from chicken meats (48.1%). A total of 3 methicillin resistant S. aureus (MRSA) were detected from beef (5.1%, 2/39) and pork (1.4%, 1/70). Although the prevalence of MRSA was low, the presence of antimicrobial resistant S. aureus such as MRSA suggests that further investigation and strict surveillance on MRSA and antimicrobial resistance are needed.

This study was carried out to investigate the antimicrobial resistance pattern and distribution of resistance gene determinants in fecal E. coli from chicken. Antimicrobial susceptibility test was performed on a total of 109 fecal E. coli isolates from chicken, collected in Gyeonggi, Chungbuk, Jeonnam and Jeonbuk province from March to November 2003, by the disk agar diffusion method. Eighteen commonly used antimicrobial agents approved in Korea as veterinary medicine were tested: ampicillin (AM), amoxicillin/clavulanic acid (AMC), cephalothin (CF), cefozolin (CZ), cefoxitin (FOX), cefotaxime (CTX), cefepime (FEP), imipenem (IPM), streptomycin (S), gentamicin (GM), amikacin (AN), ciprofloxacin (CIP), enrofloxacin (ENO), norfloxacin (NOR), trimethoprim/sulfamethoxazole (SXT), erythromycin (E), chloramphenicol (C) and tetracycline (TE). Higher resistance rates (≥50%) were observed against 9 antimicrobial agents including AM, CF, S, CIP, ENO, NOR, SXT, E and TE. Resistance was most frequent for TE in 105 E. coli isolates (96.3%). Twenty-two isolates (20.2%) of the isolates showed multiple antimicrobial resistance to 8, and 19 isolates (17.4%) showed to 7 antimicrobial agents. The distribution of the resistance gene determinants for S and TE was assessed by PCR in resistant isolates. Thirty isolates possessed the strA, strB, and aadA gene, 25 isolates possessed the strA and strB gene among the 66 streptomycin-resistant isolates. Fifty one isolates possessed only the tetA gene, 22 isolates possessed the tetA and tetB gene, 11 isolates possessed only the tetB gene among the tetracycline-resistant isolates.

The incidence of multidrug-resistant strains of Staphylococcus aureus continues to increase in hospitals and the community all over the world. As the importance of miner surgery in dentistry gets greater recently, the frequency in use of antibiotics has been increasing. Although several cases of acquired infection in oral cavity in dental hospital has been reported, the research on isolation of S. aureus and evaluation of its antibiotic resistance from outpatients in the dental clinic has not been found yet. The aim of this study was to evaluate the antimicrobial resistance of S. aureus isolates. The isolation rate of S. aureus were 41.7% in dental hospital personnel, 60.4% in outpatients and 62% in dental hygiene students. S. aureus which showed resistance to penicillin were 88.6%, ampicillin 88.6%, erythromycin 8.6%, tetracycline 4.3%, oxacillin 4.3%, cefoteten 4.3%. Six strains of S. aureus showed the susceptible to all antibiotics tested. Sixty-four(91.4%) strains were multiple antibiotic resistance. Fifty-two strains(72.8%) resisted to AM-P. and Seven strains(10.0%) resisted to AM-P-E, AM-P-GM, AM-P-TE.

서울시내에서 유통되는 식품과 식품접객업소(집단급식소 포함)의 조리식품을 대상으로 식중독 원인균 분석 및 위생미생물 검사를 실시한 결과, 분리된 대장균의 항생제 감수성 시험을 통하여 이들의 내성 정도를 파악하고, 내성 유전자와 병원성유전자의 분포도 알아보았다. 모두 1313건 의 샘플 중 50건에서 대장균이 검출되어 3.8%의 검출률을 보였다. 이중 육회 1건에서 장출혈성대장균 O26 1건, 김밥 에서 장병원성대장균 1건이 각각 검출되었다. 50건의 대장 균중 50%가 16종의 항생제에 모두 감수성을 보였으며 내성이 높게 나타난 항생제는 ampicillin(36%), amoxicillin/ clavulanic acid(32%) 그리고 tetracycline(22%)의 순이었다. 이들의 내성유전자 분포는 TEM이 1건, tetB 4건이 각각 검출되었다.

Vibrio parahaemolyticus (V. parahaemolyticus) has been recognized as a significant food-borne pathogen around the world. In this study, we investigated the prevalence and antimicrobial resistance of V. parahaemolyticus isolated from raw fishes. A total of 64 samples of raw fishes purchased from a traditional seafood market in Seoul, Korea. were examined for the presence of V. parahaemolyticus using intestines, gills, and fins. Twenty five grams of all samples were enriched in 225ml of alkaline peptone water at 37℃ for 24h and then streaked onto thiosulfate citrate bile sucrose agar. Suspected colonies were inoculated into triple sugar iron agar for biochemical screening test and were finally confirmed with API 20NE strip. Antimicrobial resistance tests were performed with disc diffusion method in accordance with National Committee for Clinical Laboratory Standard. Thirty three V. parahaemolyticus strains were isolated from raw fishes among 33 out of 64 (51.6%). Among 33 isolates, 16 isolates (48.5%) were resistant to ampicillin, 7 isolates (21.2%) were resistant to amikacin, and all isolates were not resist to other antibiotics such as amoxicillin & clavulanic acid, sulfamethoxazole & trimethopenem, ciprofloxacin, cefotaxime and cefepime. Although the prevalence of V. parahaemolyticus was high in raw fishes compared to other studies, antimicrobial resistance rate of the isolates was relatively low. These results could be useful information for risk assessment of V. parahaemolyticus in raw fishes.

From April 2008 to January 2009, a total 458 raw milk samples were randomly collected from 15 stock raising farms located in northern area of Kyunggi province and cultured for the presence of Enterococci spp. A total 170 enterococcal isolates were recovered from the raw milk samples. Enterococcus faecalis was predominant species recovered (64.7%), followed by E. faecium (18.8%), E. avium (5.9%), E. gallinarum (5.9%) and E. durans (4.7%). Antimicrobial resistance patterns of 170 Enterococci spp. against ampicillin, erythromycin, tetracyclin, chloramphenicol, vancomycin, ciprofloxacin and streptomycin were tested. According to the result, they showed high level resistance to erythromycin and streptomycin (82,9% and 93,5% respectively), moderately resistance to ampicillin, chloramphenicol and tetracyclin (50%, 45.9% and 32%, respectively) but fortunately, vancomycin and ciprofloxacin are still effective against this species.

In order to investigate phenotype and genotype of Salmonella enterica subsp. enterica serovar Enteritidis, Forty-eight S. Enteritidis isolates from diarrhea patients were analysed using antimicrobial resistance typing, Phage typing, and Pulsed field gel electrophoresis in Seoul from 2004 to 2005. All of S. Enteritidis were resistant to streptomycin(SM, 37.5%), ampicillin(AM, 43.8%), t icarcillin(TIC, 43.8%), chloramphenicol(CM, 29.2%), t etracycline(TE, 10 .4%) and nalidixic acid(NA, 18.8%) among 16 antimicrobial drugs. Of 48 S. Enteritidis, 8 isolates(16.7%) were resistant to 1 drug, 3 isolates( 6.3%) to 2 drugs, 1 isolate (2.1%) to 3 drugs and 17 isolates(35.7%) to 4 drugs. The basic pattern of 4 drugs resistance was SM, TIC, TE, and CM but 1 drug resistant isolates represent all nalidixic acid resistance. Among 30 antibiotic r esistant S . Enteritidis, 2 1 isolates(70 %) were phage type 2 1, 8 i solates(26.7%) were phage t ype 2 3 and 1 isolate( 3.3%) was RDNC, respectively. Of the phage types observed, all of phage type 23(8 isolates) were nalidixic acid resistant and phage type 21 were AM-TIC-SM-CM multi-resistance(13 isolates; 43.3%), AM-TIC-SM-TE(4 isolates; 13.3%), AM-TIC-SM(1 isolate; 3.3%), AM-TIC-CM(1 isolate; 3.3%), and AM-TIC(2 isolates; 6.7%) resistance and 1 isolate of RDNC was NA-TE resistance. PFGE divided the isolates into two major clusters, A(n=14) and B(n=14). There were four different resistance profiles with resistance to AM, TIC, SM, TE, NA within PFGE A. Also resistance to AM, TIC, SM, CM was common within PFGE B. The PFGE A strains typed as PT21(n=5), PT23(n=8), and RDNC(n=1), While all the PFGE B strains typed as PT21(n=14). In consequence, there was the highly significant concurrence between resistance typing, phage typing and PFGE.

The antimicrobial peptide possesses defence system to virus, fungi and bacteria. To study antibiotic in plant, antimicrobial peptides were obtained by PCR analysis by primers designed from antimicrobial peptides (Gene bank accession no. NM-004345), cloned in pET28 expression vector and the vector transformed into E. coli. And this gene was inserted into Ti-plasmid VB2 vector, which contained the pGD1 promoter. The expression construction was transformed into Agrobacterium EHA105 and then plant tissues of rice (Oryza sativa). Seeds from transgenic plants (T0) were germinated on selective media containing spectinomycin 50 mg/L. Selected plants and wild type were analyzed by PCR and RT-PCR with pGD1 promoter region and transgene specific primer set. All transgenic plants showed expression pattern of similar levels. We showed that the chromobody is effective in binding GFPand antimicrobial peptide gene in tobacco leaf. Most interestingly, this can be applied to interfere with the function of GFP fusion protein and to mislocalize (trap) GFP fusions to the plant cytoplasm in order to alter the phenotype mediated by the targeted proteins. Bacterial blight disease was enhanced resistance in transgenic lines. These results showed that antibiotic peptides might show a broad-spectrum antimicrobial activity.