• Korean Journal of Clinical Laboratory Science
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• v.39 no.1
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• pp.7-18
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• 2007

A total of 1,780 isolates of Enterococcus spp. were isolated from 63,133 clinical specimens from Dec 1, 2005 to Nov 1, 2006 in "C" hospital. Isolation frequencies of Enterococcus spp. were 50.9% for E. faecalis, 41.7% for E. faecium, and 7.4% for other Enterococcus spp. containing E. avium, E. gallinarum, E. casseliflavus, E. durans, E. hirae, and E. raffinosus. There were no significant difference between gender, but according to the age group analysis, Enterococcus spp. were more frequently isolated in patients over 50 years old (20.0~24.6%) than those isolated from the patients under the age of 0~49 (1.3~9.4%). In monthly analysis, Enterococcus spp. were the most frequently isolated in April (11.9%), but presented at lowest frequency in February (5.2%). Seasonal analysis did not show a significant difference. Over half of enterococci were isolated from random urine (44.9%) and catherterized urine (15.7%). Frequencies of vancomycin resistant E. faecalis and E. faecium were 0.1% and 31.0%, respectively. Teicoplanin resistant Enterococcus was 13.3% in E. faecalis, 17.6 % in E. faecium. The Enterococcus species showing over 80% susceptibility against antimicrobial agents were E. faecalis, E. durans and E. hirae in vancomycin; E. faecalis, E. gallinarum, E. casseliflavus, E. durans and E. hirae in ampicillin. The antimicrobial agent showing susceptibility against whole group of Enterococcus species was only linezolid (95.9%), and a selection of antimicrobial agent is necessary to do essential performance identification and susceptibility tests.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.301-310
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• 2000

The antimicrobial susceptibility, genotypes of enterotoxins(LT, STa) and pili(K88, 987P), and plasmid profiles were investigated with 102 Escherichia coli isolated from piglets showing diarrhea in Korea. Almost of them were susceptible to ceftiofur(99%), cefquinone(97.1%). However they showed resistance to bacitracin(100%), streptomycin(98%), vancomycin(97%), trimethoprim/sulfamethoxazole(87.2%), tetracycline(84.3%) in antimicrobial susceptibility test. Moreover, all of the isolates demonstrated resistance to more than 2, and 78% of them were resistant to more than 8 of total 17 drugs. Multiplex PCRs for genotyping of enterotoxins(LT, STa) and pili(K88, 987P) were established with primers designed based on sequences from Genebank. Seventeen strains(16.6%) of the isolates had STa gene, 11 strains(10.8%) of them had both STa and LT genes, and 18 strains(17.8%) had K88 gene. But none of the isolates harbored a gene exclusively encoding LT. The gene encoding 987P pili was not found in all isolates. Fifty-four strains of 102 isolates(52.9%) had plasmid with various sizes ranging from 125kb to 1.1kb. Numbers of plasmid per isolates were also various, from 1 to 9. Distinctive relationship between plasmid profiles and genotypes of enterotoxins and pili in the isolates was not found. These results might provide the basic knowledge to establish strategies for the treatment and prevention of colibacillosis in piglets.

• Journal of Microbiology and Biotechnology
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• v.18 no.11
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• pp.1853-1857
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• 2008

Salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. A total of 21 isolates of Salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. Among these, 18 isolates were identified as Salmonella enterica serotype Haardt (S. Haardt) and three isolates were S. enterica serotype Muenchen. When the minimal inhibitory concentrations of the S. Haardt isolates were assayed with the agar dilution method to determine susceptibility to ampicillin, chloramphenicol, sulfisoxazole, tetracycline, and nalidixic acid, all 18 isolates were resistant to tetracycline and nalidixic acid and nine of these were resistant to ampicillin. These isolates showed reduced susceptibility to eight fluoroquinolones including ciprofloxacin, enrofloxacin, levofloxacin, gatifloxacin, gemifloxacin, moxifloxacin, norfloxacin, and ofloxacin. When quinolone resistance determining regions of gyrA and gyrB were sequenced, every isolate had the same missense mutation Ser83$\rightarrow$Tyr (TCC$\rightarrow$+TAC) in gyrA, whereas no mutation was found in gyrB. Pulsed-field gel electrophoresis with XbaI revealed a close relationship among these isolates, suggesting a contamination of raw chicken meat with clonal spread of nalidixic acid-resistant and quinolone-reduced susceptibility S. Haardt in chickens. Results in this study show the importance of a well-equipped cold system and the prudent use of fluoroquinolone in chickens to prevent the occurrence of quinolone-resistant isolates.

• Tuberculosis and Respiratory Diseases
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• v.86 no.1
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• pp.47-56
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• 2023

Background: There is a global increase in isolation of nontuberculous mycobacteria (NTM). The aim of the study was to analyze longitudinal trends of NTM identification and pattern of antimicrobial susceptibility testing. Methods: NTM recovery rates, distribution of NTM species identification, and antimicrobial susceptibility pattern of NTM at Pusan National University Yangsan Hospital between January 2016 and December 2020 were retrospectively analyzed. Results: A total of 52,456 specimens from 21,264 patients were submitted for mycobacterial culture, of which 2,521 from 1,410 patients were NTM positive over five years (January 2016 to December 2020). NTM isolation showed an increasing trend from 2016 to 2020 (p<0.001, test for trend) mainly caused by Mycobacterium avium complex. The vast majority of M. avium complex were susceptible to key agents clarithromycin and amikacin. For Mycobacterium kansasii, resistance to rifampin and clarithromycin is rare. Amikacin was the most effective drug against Mycobacterium abscessus subspecies abscessus and Mycobacterium subspecies massiliense. Most of M. subspecies massiliense were susceptible to clarithromycin, while the majority of M. abscessus subspecies abscessus were resistant to clarithromycin (p<0.001). Conclusion: There was an increasing trend of NTM isolation in our hospital. Resistance to key drugs was uncommon for most NTM species except for M. abscessus subspecies abscessus against clarithromycin.

• Korean Journal of Veterinary Service
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• v.15 no.1
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• pp.81-88
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• 1992

This study was conducted to determine the microorganisms inhabitating in sow genital organs and their anti-microbial drug susceptibility During the period between February, 1991 and November 1991, 128 sow genital organs were sampled at six abattoirs. Gross pathological examination and bacterial isolation and identification were performed from the genital organ. In addition, antimicrobial drug susceptibility for the major organisms isolated were examined. 1. Among the bateria isolated from normal genital organs, E. coli(30.7%) Stahylococcus spp.(29.4%), Corynebarterium pyogenes(C. pyogenes) (14.7%), Streptococcus spp.(13.3%) were most freqently isolated, whereas the genera of Klebsiella, Actinobacillus, and Serratia were detected less freqently. 2. Among the bacteria isolated from abnormal genital organs, C. pyogenes,(37.7%), Stahylococcus spp.(30.2%), Proteus spp. (26.4%) , Pasteurella spp. (18.9%) , Steptococcus spp. (9.4%) were most freqently isolated whereas the genera of Pseudomonas, Serratia and Klebsiella were detected less freqently. 3. From sow genital organs showing lesion of endometritis and purulent endometritis C. pyogenes were most freqently isolated, the isolation rate being 67.7％ and followed by Stahylococcus spp., E. coli, Proteus spp., Steptococcus spp. and Pasteurella spp. in the order. 4. Antimicrobial drug susceptibility of the major organisms showed that all the isolates were susceptible to cephalothin, ampicillin, chloramphenicol and sulfamethoxazole / trimethoprim, but resistant to penicillin and streptomycin.

• 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.

• Korean Journal of Veterinary Service
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• v.44 no.1
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• pp.21-26
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• 2021

The aim of this study was to investigate the antimicrobial resistance among Pseudomonas (P.) aeruginosa isolated from dogs and cats. A total of 45 (6.2%) P. aeruginosa was isolated from 710 dogs and 21 cats with clinical signs. Resistance to one or more of the antimicrobials tested was observed in 26 (57.8%) P. aeruginosa. Resistance to cefepime was the most frequent (44.4%), followed by ofloxacin (22.2%), levofloxacin (17.8%), norfloxacin (8.9%), ciprofloxacin (6.7%), ceftazidime, aztreonam, colistin, polymixin B and gentamicin (4.4%, respectively), while resistance to piperacillin/tazobactam, imipenem, tobramycin and amikacin was 2.2%, respectively. All isolates were susceptibility to doripenem and meropenem. Antimicrobial susceptibility testing should be a crucial step in selection of appropriate antimicrobial therapy in veterinary medicine. Also, the prudent use of antimicrobials and continuous monitoring for companion animals are required.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.826-832
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• 2023

Clostridium perfringens causes diarrhea and other diseases in humans and animals. We investigated the prevalence, toxin gene profiles, and antimicrobial resistance of C. perfringens isolated from commercial jeotgal sample. C. perfringens was isolated from 11 of 22 commercial jeotgals. All C. perfringens strains were positive for the alpha toxin gene, but not for the beta, epsilon, iota, CPE or NetB toxin genes; therefore, all strains were identified as type A C. perfringens. However, the beta2 toxin gene was identified in 54.5% of isolates. Disk diffusion susceptibility tests showed that most isolates were resistant to kanamycin (90.9%), nalidixic acid (72.7%), oxacillin (54.5%), erythromycin (27.3%), ciprofloxacin (9.1%) and clindamycin (9.1%). However, all strains were susceptible to 14 other antimicrobial including amoxicillin, ampicillin, and chloramphenicol. The average minimum inhibitory concentrations against C. perfringens of clindamycin, kanamycin, and nalidixic acid were 128.0, 128.0, and 54.0 ㎍/mL, respectively. These results provide new insight into the necessity for sanitation of commercial jeotgal, and provide evidence to help reduce the risk of contamination with antimicrobial-resistant bacteria.

• Korean Journal of Veterinary Research
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• v.31 no.2
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• pp.201-208
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• 1991

In studies on Erysipelothrix rhusiopathiae infection of pigs, a series of investigations were conducted for isolation, biochemical properties, pathogenicity, serotyping and susceptibility to antimicrobial agents. The results could be summarized as follows: 1. A total of 14 isolates of E rhusiopathiae were made from an acute form of swine erysipelas and the incidence was high during the hot summer season. 2. The biochemical properties of the 14 isolates were identical to the reference strain of E rhusiopathiae. 3. Pathogenicity of the isolated strain(89368) were ascertained that $LD_{50}$ for mice was $1.8{\times}10 $ cfu and also typical urticarious lesions and acute septicemia for pigs were induced by intradermal and intravenous inoculation with isolates, respectively. 4. All isolates were serotyped by the agarose gel slide double-diffusion system and proved to be serotype 1. 5. In susceptibility test to antimicrobial agents, 14 isolates of E rhusiopathiae were highly sensitive to ampicillin, baytril, cephalothin, chloramphenicol, penicillin and tetracycline.

• Food Science of Animal Resources
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• v.37 no.2
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• pp.175-180
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• 2017

The objectives of this study were: i) to detect the presence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in raw milk, cheese, beef minced meat, and chicken meat samples; ii) to evaluate the antimicrobial susceptibility of the isolates; and iii) to determine clonal relation among the isolates by using pulsed-field gel electrophoresis (PFGE) method. Therefore, a total of 160 food samples were randomly collected between August 2014 and May 2015 in Hatay province, located in the southern Turkey. Twenty (12.5%) of the samples were found to be contaminated with S. aureus. A total of 40 isolates from the 20 positive samples were confirmed to be S. aureus by multiplex PCR based on 16S rRNA and nuc gene. The mec A gene was not detected in any of the S. aureus strains. In the present study, 39 out of 40 (97.5%) isolates were found to be resistant to one or more antibiotics. All of isolates were susceptible to gentamicin, oxacillin, and vancomycin. The highest resistance rate was detected in penicillin (95%) and ampicillin (92.5%), followed by tetracycline (30%), erythromycin (20%), ciprofloxacin (12.5%). Nine major patterns were determined by PFGE. In 6 of these patterns, thirty-six strains (90%) had identical PFGE profiles.