• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.327-334
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• 2016

Recently, antimicrobial resistance of pathogenic bacteria has been increasing due to excessive use of antimicrobial agents in both humans and livestock. PCR amplification and nucleotide sequence analyses were conducted to investigate16S ribosomal RNA methyltransferase (RMTase) genes and integrons in P. mirabilis strains isolated from clinical specimens and chickens in an area of the Chungcheong providence. In addition, clonality analysis of P. mirabilis strains was performed using a repetitive extragenic palindromic sequence-based PCR (REP-PCR) method. Of the total 38 P. mirabilis isolates, 7 (18.4%) strains were isolated from clinical specimens contained in the RMTase genes and showed resistance to amikacin, tobramycin, and gentamicin. A total of 23 (60.5%) isolates carried class 1 integrons, but no isolates in our study harbored class 2 and class 3 integrons. Class 1 integrons detected in our study harbored genes encoding resistance to aminoglycosides (aadA2, aadA5, aadA7, and aacCA5), ${\beta}$-lactams ($bla_{PSE}$), erythromycin (ereA), lincosamides (linF), and trimethoprim (dfrA12, dfrA17, and dfrA32). We confirmed that the RMTase genes had spread among only the P. mirabilis isolates from clinical specimens, but class 1 integrons had widely disseminated among P. mirabilis isolates from clinical specimens and chickens. In addition, identical REP-PCR banding patterns were evidenced in only P. mirabilis isolates from chickens. Our results suggest the horizontal spreading of P. mirabilis isolates in the chicken farm. To prevent further spreading of antimicrobial resistant genes among P. mirabilis isolates, monitoring and clinical policing will be required.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.493-501
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• 1989

A total of 108 strains of C jejuni isolated from pigs and chickens were examined for the susceptibility to 10 antimicrobial agents and normal sera of cattle, sheep, guinea pigs and chickens. Minimal inhibitory concentration(MIC) ranges of antimicrobial agents to C jejuni isolates were $${\leq_-}1.56$$ to $${\geq_-}100{\mu}g/ml$$ for erythromycin, rifampin, streptomycin and tetracycline, 50 to $${\geq_-}100{\mu}g$$ for cephalothin, $${\leq_-}1.56$$ to $50{\mu}g$ for ampicillin, $${\leq_-}1.56$$ to $25{\mu}g$ for kanamycin and nalidixic acid, $${\leq_-}1.56$$ to $12.5{\mu}g$ for chloramphenicol and gentamicin. Resistance rates of C jejuni were showed to in order of rifampin(84.7%), tetracycline(56.2 %), erythromycin(17.1%) and ampicillin(3.8%), all of the strains were sensitive to chloramphenicol, gentamicin and kanamycin, and the incidence rates of resistant C jejuni were highly frequent in pig isolates than chicken isolates. The drug resistance patterns of 87 chicken isolates C jejuni to 9 antimicrobial drugs were showed 12 patterns, and Sm Ra Tc(24.1%), Sm Ra(21.8%) and Ra Tc(14.9%) were relatively common, and also 21 pig isolates were showed 6 patterns and Em Sm Ra Tc(57.1%) were most frequent. The majority of the isolates showed multiple drug resistance. Bactericidal activity of 10% normal sera from healthy animals were examined for 60min at $37^{\circ}C$. C jejuni were decreased from 0.4 to 1.0 ${\log}_{10}$(p<0.01), and serum susceptibility were high in order of guinea pig, sheep, chicken and cattle sera. Serum sensitivity of C jejuni Ch-39 strain in increased serum concentation up to 10, 20, 40 and 80% were highly significant. In the normal animal serum, the number of Ch-39 strain were decreased from $1.8{\times}10^4/ml$ to $2.7{\times}10^3/ml$ after 60 min incubation(p<0.01), but the numbers were decreased to $6.6{\times}10^3/ml$ in the heat inactivated normal serum for 30 min at $56^{\circ}C$. Bactericidal activity was restored in the heat inactivated normal serum after the serum of complement source was added.

• Korean Journal of Veterinary Service
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• v.32 no.3
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• pp.227-239
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• 2009

At the present study, it was aimed to detect virulence genes and antimicrobial resistance genes among 102 strains of 12 Salmonella serotypes isolated from pigs and cattle. In polymerase chain reaction (PCR), invA was detected from all strains of Salmonella spp., spvC was detected from Salmonella enterica serotype Enteritidis (S. Enteritidis) (100%), S. Bradenburg (75%), and S. Typhimurium (20.4%). Drug resistance related genes of 12 types were detected from all strains. TEM ($bla_{TEM}$) gene was detected from 51 (92.7%) of 55 $\beta$-lactams (54 ampicillin or 1 amoxicillin) resistance strains. 55 (100%) of 55 chloramphenicol resistance strains, 3 (100%) of 3 gentamicin resistance strains and 5 (100%) of 5 kanamycin resistance strains did contain cml, aadB, and aphA1-Iab, respectively. strB (89.9%), strA (88.4%), aadA2 (84.1%) and aadA1 (72.5%) were detected from 69 streptomycin resistance strains. sulII and dhfrXII were detected from 49 (100%) of 49 sulfamethoxazole/trimethoprim resistance strains, but sulI was not detected. tetA (97.9%) and tetB (21.6%) were detected from 97 tetracycline resistance strains. int gene was detected from 58 (56.9%) of 102 strains. 54 S. Typhimurium of 102 Salmonella spp. were attempted to detect drug resistance genes. TEM was detected from 44 (95.7%) of 46 $\beta$-lactams (45 ampicillin or 1 amoxicillin) resistance strains. cmlA was detected from 51 (100%) of 51 chloramphenicol resistance strains. aadA2 (100%), strA (100%), strB (100%), and aadA1 (79.6%) were detected from 54 streptomycin resistance strains. sulII (100%) and dhfrXII (100%) were detected from 49 sulfamethoxazole/trimethoprim resistance strains. tetA was detected from 54 (100%) of 54 tetracycline resistance strains. int gene was detected from 54 (100%) of 54 strains. The major drug resistance pattern and resistance gene profile were ampicillin, chloramphenicol, streptomycin, sulfamethoxazole/trimethoprim and tetracycline (ACSSuT) and TEM, cmlA, aadA1, aadA2, strA, strB, sulII, dhfrXII, tetA and int, respectively.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1276-1284
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• 2006

Listeria monocytogenes is a well-known high-risk foodborne pathogen that grows at refrigeration temperature and is responsible for outbreaks of listeriosis. We report here the incidence of L. monocytogenes in fresh chicken carcasses and present genetic diversity of L. monocytogenes isolates. In this study, 25 g of chicken carcasses from markets in Korea were examined according to the FDA method, and presumptive isolates were confirmed by multiplex PCR assay. L. monocytogenes isolates were analyzed by Pulsed-Field Gel Electrophoresis using restriction enzymes, ApaI and AscI, to obtain strain-specific DNA fragments profiles. Antimicrobial resistance of L. monocytogenes strains against generally used antibiotics (Penicillin G, Kanamycin, Tetracycline, Vancomycin, Cephalothin, Rifampicin, Erythromycin, Ampicillin, Gentamicin, Streptomycin, and Chloramphenicol) were analyzed by NCCLS protocols to examine the presence of antimicrobial resistance in natural L. monocytogenes. Of a total 274 chicken samples, 81 samples (29.6%) were positive for L. monocytogenes. Listeria innocua (50.1%), Listeria welshimeri (6.9%), and Listeria grayi (11.3%) were also detected. PFGE analysis, using restriction enzymes ApaI and AscI, showed 27 pulsotypes of L. monocytogenes. Antimicrobial resistance analysis confirmed the existence of antimicrobial resistance for penicillin G and tetracycline in isolated L. monocytogenes strains.

• Korean Journal of Veterinary Service
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• v.40 no.2
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• pp.101-105
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• 2017

The purpose of this study was to investigate prevalence and antimicrobial resistance patterns of Campylobacter spp. from duck feces in northern area of the Gyeongnam province, Korea. Samples of 121 duck feces were taken from April to December 2014 for this survey. Samples were examined by bacteria isolation and reverse transcriptase-polymerase chain reaction assay for detection of Campylobacter spp. Campylobacter were isolated in 37 samples (30.6%). Among these samples, C. jejuni and C. coli were isolated in 35 samples and 2 samples, respectively. Minimum inhibitory concentration (MIC) test is performed to investigate antimicrobial resistance patterns of Campylobacter spp. C. jejuni were resistant to ciprofloxacin (85.7%), nalidixic acid(82.9%), tetracycline (77.1%), gentamicin (57.1%), azithromycin (40.0%), clindamycin (34.3%), erythromycin (22.9%), and florfenicol (8.6%). These data support a database of pollution and antimicrobial resistance of Campylobacter spp. from duck feces and provide a basic information of reducing the secondary damage of antibiotic misuse.

• Korean Journal of Veterinary Service
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• v.37 no.1
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• pp.19-27
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• 2014

This study was conducted to investigate the antimicrobial resistance, presence of ${\beta}$-lactamase genes and integrons in 83 ESBL-producing Escherichia coli isolated from Nakdong river and Geumho river in Daegu. Among the ${\beta}$-lactam antimicrobials, all isolates were resistant to ampicillin, cephalothin, cefamandole and cefotaxime, followed by piperacillin (98.8%), ampicillin/sulbactam (86.7%), aztreonam (60.2%) and cefepime (59.0%), whereas resistance to piperacillin/tazobacram, ticarcillin/clavulanic acid and cefoxitin was less than 30%. Many of the ESBL-producing Escherichia coli were also resistant to non-${\beta}$-lactams antimicrobials such as nalidixic acid (83.1%), sulfonamides (72.3%), ciprofloxacin (62.7%) and gentamicin (38.6%). All isolates showed resistance to seven or more antimicrobial agents. The most frequently detected gene was $bla_{TEM+CTX-M}$ (49.4%), followed by $bla_{CTX-M}$ (27.7%), $bla_{TEM}$ (6.0%) and $bla_{OXA}$ (1.2%). But $bla_{SHV}$ was not found. Class 1 integrons were found in 61.4% (51 isolates) of isolates, however, class 2 and 3 integrons were not detected. The results showed water from Nakdong river and Geumho river is contaminated with ESBL-producing E. coli isolates. These results suggest the need for further investigation of antibiotic resistant bacteria to prevent public health impacts in the water environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.626-633
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• 2023

Vibrio spp. are aquatic bacteria that are ubiquitous in warm estuarine and marine environments. Especially, V. vulnificus and V. cholerae are currently known to cause potentially fatal infections in humans. This study investigated the distribution and antibiotic resistance of V. vulnificus and V. cholerae isolated from coastal areas of Gyeongsangnam-do in 2022. A total of 252 samples of water, shellfish and coastal sediment were collected from 7 locations along the coast, and 124 samples of fishery products were collected from markets. Among the 252 samples, forty-four V. vulnificus (11.7%) and fourteen V. cholerae non-O1/non-O139 (3.7%), none of which carried the ctx gene, were isolated. Out of the 124 samples, 6 (4.8%) tested positive for V. vulnificus and V. cholerae was not detected. The isolation rates of V. vulnificus and V. cholerae showed a significant correlation with environmental factors such as seawater temperature and salinity. In an antibiotic resistance test, V. vulnificus was susceptible to amikacin, gentamicin, imipenem trimethoprim/sulfamethoxazole, and ciprofloxacin, but resistant to cefoxitin (100.0%), followed by tetracycline (9.1%). Multidrug resistance was also observed. Continuous monitoring of Vibrio pathogens with water temperature and salinity is expected to help reduce the outbreaks, and rational use of antibiotic agents is needed to prevent the accession of antibiotic-resistant microorganisms in aquatic ecosystems.

• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.11-24
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• 1984

Shigella remains to be an important enteric pathogen in this country for the present. Moreover, most of the isolates have become multiple resistant to various antibiotics which used to be drugs of choice for shigellosis. This study was made as an attempt to assess the present stage of antibiotic resistance and the incidence and transferability of R factors of Shigella. A total of one hundred and seventeen strains of Shigella isolated from patients in Seoul and provincial area between 1982 and 1983 were tested for their resistant to antimicrobial agents and transmission of R-plasmid. Antibiotic susceptibilities were determined by an agar dilution method. Muller hinton agar were used for the assay of drug resistance and tryptic soy broth were used for propagating medium for conjugation. Shigella isolated found to be one or more antibiotics were considered potential donor of R-plasmid. The following results were obtained. 1. Among 117 strains of Shigella isolated, 111 strains(94.9%) were found to be resistant to one or more drugs tested and 97.3% of these resistant strains were multiply resistant, indicating the multiply resistant strains were more than the single resistant strains. Only six strains were susceptible to all drugs tested. 2. Among 117 strains of Shigella isolated, 107 strains(91.5%) were resistant to Tetracyclin(Tc), 106 strains(90.6%) to Chloramphenicol(Cp) and Streptomycin(Sm), 97 strains(82.9%) to Ampicillin(Ap), 68 strains(58.1%) to Cephaloridine(Cr), 10 strains(8.5%) to Nalidixic acid(Na), 5 strains(4.3%) to Kanamycin(Km) and 2 strains(1.7%) to Rifampicin. No strain was resisfant to Amikacin(Ak) and Gentamicin(Gm). 3. All drug-resistant Shigella strains, except three, were multiply resistant to two or more drugs. Fifty eight strains were resistant to five drugs, followed by 26 strains resistant to dour drugs, 12 strains resistant to three drugs and 11 strains resistant to six drugs. 4. The 73% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation and the resistance was considered to be mediated by R-plasmid. Resistance to Nalidixic acid and Rifampicin were not transferred by conjugation to recipient. As for the transferability of resistance to each seperate drug, Ap resistance was transferred with 73.2% frequence and Cm and Tc resistance were transferred with approximately 50-60% frequence whereas Sm and Cr resistance were transferred in 19.1-21.4% The other four drugs resistant failed to transfer their resistance to recipient. 5. As for the incidence and transferability of resistance to each seperate drug, the strains resistant to Tc and Cm were encountered most frequently with the rate of 91-92%, whereas transfer of Tc and Cm were low, 51-52%. The incidence of Sm resistance was very high(90.6%) but transferability of drugs resistance was much lower(25.4%). Though the incidence of Km reristance was much lower(4.3%) transferability of Km resistance was considerably higher(60%). 6. The greater the multiplicity of resistance, the greater was the likelihood that part of all of the resistance markers would be transferable.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.27-37
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• 1979

Ninety-five strains of Shigella, 70 of Salmonella paratyphi A, and 230 of Salmonella typhi were tested for their resistance to drugs. Also studied was the inhibition and elimination of drug resistance. All except one strain of Shigella consisted of 79 Sh. flexneri and 16 Sh. sonnei were multiply resistant to chloramphenicol, tetracycline, streptomycin, and splfisomidine. Among them, 70 strains were resistant to ampicillin and carbenicillin, 80 to trimethoprim-sulfamethoxazole, 22 to nalidixic acid, and one to kanamycin, but strain resistant to gentamicin, cephaloridine, and rifampin was not encountered. All strains of S. paratyphi A and S. typhi were susceptible to drugs tested, except sulfisomidine and rifampin, for which all S. paratyphi A were slightly resistant to sulfisomidine and the majority of S. paratyphi A and S. typhi were slightly resistant to rifampin. Approximately 80% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation, and the resistance was considered to be mediated by R plasmids. The frequency of transfer of drug resistance varied by donor strains and recipients, but not by selecting drugs. Resistance to nalidixic acid was not transferred by conjugation to the recipients. Drug-resistant Shigella strains successively subcultured in nutrient agar stabs contained clones resistant to drugs and those susceptible to drugs, but the ratio of resistant and susceptible clones varied by strains. The multiply drug-resistant S. typhi and Shigella strains were found to not lose completely their drug resistance by subculture in media. Acriflavine has some effect on the elimination of drug resistance mediated by R plasmids, but the effect varied markedly by strains. Atabrine has no effect among strains tested. The combination of drugs increased the drug actions in majority of cases with synergistic or additive effects.

• Korean Journal of Veterinary Research
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• v.29 no.3
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• pp.291-301
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• 1989

To investigate the epidemiological trait of intestinal diseases of animals caused by thermophilic Campylobacter spp., isolation of etiological agent was carried out. Isolated Campylobacter spp. were biotyped, serotyped and the susceptibility of the isolates to antimicrobial agents were examined. Th results were as follows. 1. Isolation rates of Campylobacter spp. from 649 fecal materials of 208 cattle, 300 pigs and 141 chickens were 25.5%, 23.7% and 38.3%, respectively. 2. The majority of the 130 isolates of C jejuni was classified as biotype I(50.6%) and biotype II (34.6%). Most of the 46 isolates of C coli were biotype I (71.7%). 3. Isolated C jejuni strains showed 14 different serotype, and serotype 4, 26, 36 were most frequent. Isolated C coli strains showed 5 different serotype and serotype 31 and 21 were relatively common. 4. Isolated Campylobacter spp. were highly susceptible to nalidixic acid, amikacin, gentamicin, colistin and chlorampehnocol.