• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.500-510
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• 2023

In this study, lactic acid bacteria were isolated from 21 top-selling probiotic products on Korean market and their antimicrobial resistance were analyzed. A total 152 strains were claimed to be contained in these products and 70 isolates belonging to three genera (Bifidobacterium, Lactobacillus, and Lactococcus) were obtained from these products. RAPD-PCR showed diversity among isolates of the same species except for two isolates of Lacticaibacillus rhamnosus from two different products. The agar dilution method and the broth dilution method produced different MICs for several antimicrobials. With the agar dilution method, five isolates (three isolates of Bifidobacterium animalis subsp. lactis, one isolate of B. breve, one isolate of B. longum) were susceptible to all nine antimicrobials and 15 isolates were multi-drug resistant. With the broth microdilution method, only two isolates (one isolate of B. breve and one isolate of B. longum) were susceptible while 16 isolates were multi-drug resistant. In this study, only two AMR genes were detected: 1) lnu(A) in one isolate of clindamycin-susceptible and lincomycin-resistant Limosilactobacillus reuteri; and 2) tet(W) in one tetracycline-susceptible isolate of B. longum B1-1 and two tetracycline-susceptible isolates and three tetracycline resistant isolates of B. animalis subsp. lactis. Transfer of these two genes via conjugation with a filter mating technique was not observed. These results suggest a need to monitor antimicrobial resistance in newly registered probiotics as well as probiotics with a long history of use.

• Korean Journal of Veterinary Service
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• v.36 no.1
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• pp.57-60
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• 2013

This study was carried out to investigate the prevalence and antimicrobial resistance patterns of Campylobacter jejuni isolated from duck feces. In total, 112 (32.9%) isolates of C. jejuni were identified from 430 duck feces samples from September to December, 2010. All isolates were susceptible to telithromycin, whereas majority of the C. jejuni isolates were resistant to azithromycin (18.8%), ciprofloxacin (86.6%), erythromycin (0.9%), gentamicin (15.2%), tetracycline (80.4%), florfenicol (3.6%), nalidixic acid (87.5%), clindamycin (7.1%). As a result, appropriate protocols for antimicrobial agents and strategies to reduce antimicrobial resistance will be needed in the future.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.221-227
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• 2013

In total, 131 Escherichia coli isolates from surface seawater of the Gomso Bay, of Korea, were analyzed for their susceptibility to 22 different antimicrobials and for genes associated with antimicrobial resistance and virulence. According to the disk diffusion susceptibility test, the resistance to tetracycline was most prevalent (33.6%), followed by that to ampicillin (22.1%), ticarcillin (22.1%), and trimethoprim (16.8%). More than 46.6% of the isolates were resistant to at least one antimicrobial, and 22.9% were resistant to three or more classes of antimicrobials; these were consequently defined as multidrug resistant. We further found that 29 ampicillin-resistant isolates possessed genes encoding TEM-type (93.1%) and SHV-type (6.9%) ${\beta}$-lactamases. Among the 44 tetracycline-resistant isolates, tetA and tetC were found in 35 (79.5%) and 19 (43.2%), respectively, whereas tetB was detected in only three isolates (6.8%). With regard to virulence genes, merely 0.8% (n = 1) and 2.3% (n = 3) of the isolates were positive for the enteroaggregative E. coli-associated plasmid (pCVD432) gene and the enteropathogenic E. coli-specific attaching and effacing (eae) gene, respectively. Overall, these results not only provide novel insight into the necessity for seawater sanitation in Gomso Bay, but they help reduce the risk of contamination of antimicrobial-resistant bacteria.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.856-867
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• 2020

Vibrio parahaemolyticus is a major gastroenteritis-causing pathogen in many Asian countries. Antimicrobial resistance in V. parahaemolyticus has been recognized as a critical threat to food safety. In this study, we determined the prevalence and incidence of antimicrobial resistance in V. parahaemolyticus in the southern Fujian coast, China. A total of 62 isolates were confirmed in retail aquatic products from June to October of 2018. The serotype O3:K6 strains, the virulence genes tdh and trh, antibiotic susceptibility and molecular typing were investigated. Then plasmid profiling analysis and curing experiment were performed for multidrug-resistant strains. The results showed that the total occurrence of V. parahaemolyticus was 31% out of 200 samples. Five strains (8.1%) out of 62 isolates were identified as the V. parahaemolyticus O3:K6 pandemic clone. A large majority of isolates exhibited higher resistance to penicillin (77.4%), oxacillin (71%), ampicillin (66.1%) and vancomycin (59.7%). Seventy-one percent (44/62) of the isolates exhibited multiple antimicrobial resistance. All 62 isolates were grouped into 7 clusters by randomly amplified polymorphic DNA, and most of the isolates (80.6%) were distributed within cluster A. Plasmids were detected in approximately 75% of the isolates, and seven different profiles were observed. Seventy-six percent (25/33) of the isolates carrying the plasmids were eliminated by 0.006% SDS incubated at 42℃, a sublethal condition. The occurrence of multidrug-resistant strains could be an indication of the excessive use of antibiotics in aquaculture farming. The rational use of antimicrobial agents and the surveillance of antibiotic administration may reduce the acquisition of resistance by microorganisms in aquatic ecosystems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.1-7
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• 2018

We investigated patterns of antimicrobial resistance in Escherichia coli isolated from the water discharged from inland pollution sources in the Hansan-Geojeman and Jaranman-Saryangdo areas of Korea. A total of 217 strains of E. coli were isolated from 23 point-sources. These strains were tested for their susceptibility to 16 antimicrobial agents used in Korea for medical or veterinary therapy. The highest level of antibiotic resistance among the isolated strains was to tetracycline 10.6%, followed by ampicillin (3.2%), nalidixic acid (2.8%), rifampin (1.8%), trimethoprim (1.8%), trimethoprim/sulfamethoxazole (1.8%), chloramphenicol (1.4%), streptomycin (1.4%), cephalothin (0.5%) and gentamicin (0.5%). Resistance to at least one antimicrobial agent was present in 17.1% of the E. coli isolates. Only four of the isolated strains of E. coli showed multiple antibiotic resistance, which is defined as resistance to more than four antibiotics.

• Animal Bioscience
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• v.34 no.4
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• pp.734-742
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• 2021

Objective: The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential. Methods: A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex polymerase chain reaction-based assays using the specific primer sets. Results: A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%), and sen (28%), which were carried by 81% of S. saprophyticus. Conclusion: These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as staphylococcal cassette chromosome mec and tet(K).

• Korean Journal of Veterinary Service
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• v.40 no.2
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• pp.83-87
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• 2017

59 strains of Salmonella enterica subspecies enterica serovar Typhimurium (S. Typhimurium) were isolated from pigs in Gyeongbuk province, collected from 2011 to 2016. The isolates were investigated for the presence of antimicrobial resistance and multi drug resistance patterns. All 59 S. Typhimurium isolates were resistant to at least one of 10 antibiotics used in this study, 100% of S. Typhimurium isolates from pigs were resistant to two or more antimicrobials. As many as 5 isolates of isolates from pigs were resistant to 8 of 10 antimicrobials tested in this study. The ACSTNaGmKNaCf, ACSTGmAuKT/S, ACSTGmKCfT/S resistance phenotype was observed in 3.4%, 3.4%, 1.7% of the 59 isolates, respectively.

• Journal of Yeungnam Medical Science
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• v.27 no.1
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• pp.8-17
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• 2010

It is important to select appropriate antimicrobials for the treatment of infection according to the results of antimicrobial susceptibility tests (ASTs), yet the clinical isolates are sometimes susceptible to antibiotics that are clinically ineffective or this is due to technical error of the ASTs. So, interpretive reading of ASTs is needed and especially for the ${\beta}$-lactams for treating $Enterobacteriacae$. This review describes the interpretive reading of ASTs according to natural antimicrobial resistance and the mechanisms of mechanisms, with giving special attention to the antibiotics phenotypes for $Enterobacteriacae$. Further, as all the diffent tissues have a different antimicrobial concentration for identical antimicrobials, more information is needed on the antimicrobial tissue distribution for the appropriate treatment of infection. (ED note: I hope you send me the paper.)

• Korean Journal of Veterinary Service
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• v.39 no.1
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• pp.51-57
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• 2016

Fifty and forty two Salmonella enterica subspecies enterica serovar 52 Typhimurium (ST) strains were isolated from chicken and pigs, respectively, collected from markets throughout Korea from 2008 to 2011. The isolates were investigated for the presence of antimicrobial resistance and multi-drug patterns. All 50 ST isolates from chicken and 42 ST isolates from pigs were resistant to at least one of 13 antibiotics used in this study, 92.0% of ST isolates from chicken and 88.1% of ST isolates from pigs were resistant to three or more antimicrobials. As many as 3 isolates of ST isolates from chicken were resistant to 11 of 13 antimicrobials tested in this study. Only one isolate of ST isolates from pigs was resistant to 10 of 13 antimicrobials. The ACSSuT resistance phenotype was observed in 34% of the 50 isolates and 23.8% of the 42 isolates. Especially, 1 isolate from pigs had the ACSSuTAu. The high rate of antimicrobial-resist and multi-drug resistant (MDR) ST isolation may give rise to crucial public health problems. Therefore, control of antimicrobial use, and continuous monitoring of antimicrobial resistance and MDR patterns among Salmonella isolates in chicken and pig farms is necessary to ensure public health.

• YAKHAK HOEJI
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• v.33 no.2
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• pp.73-79
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• 1989

One hundred and sixteen strains of E. coli isolated from drainage in Seoul city in 1987 and 104 strains of E. coli isolated from stools of domestic animals in suburb of Seoul in 1987 were examined for susceptibilities to 10 antimicrobial agents by the agar dilution method. The susceptibilities of the two groups to each antimicrobial agent were compared and correlations in the antimicrobial susceptibility of the 220 strains of E. coli among the 10 antimicrobial agents were also analyzed. The frequency of resistance strains was highest to tetracycline with 77%, and followed by chloramphenicol, streptomycin, ampicillin, kanamycin and cephalosporin in the descreasing order, tanging from 62% to 10%. Strains resistant to tobramycin, nalidixic acid, gentamicin and amikacin occupied 3 strains, 2 strains, 2 strains and 1 strain respectively.