• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.870-877
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• 2020

Twenty-three Bacillus cereus strain isolated from commercial jeotgal were investigated for 11 toxin genes and susceptibility to 25 different antimicrobials. The hemolytic enterotoxins hblA, hblC, and hblD were detected in 13.0%, and non-hemolytic enterotoxins nheA, nheB, and nheC were detected in 26.1%, 100%, and 100% of the isolates, respectively. The positive rates of cytK, entFM, becT, hlyII, and ces were 73.9%, 60.9%, 26.1%, 8.7%, and 0.0%, respectively. According to the disk diffusion susceptibility test, all of the strains studied were resistant to cefuroxime, followed by cefoxitin (78.3%), oxacillin (78.3%), ampicillin (69.6%), penicillin G (69.6%), and amoxicillin (65.2%). However, all the strains were susceptible to 11 other antimicrobials, including amikacin, chloramphenicol, and ciprofloxacin. The average minimum inhibitory concentrations of amoxicillin, ampicillin, and cefuroxime against B. cereus were 462.9, 235.0, and 135.0 ㎍/mL, respectively. These results highlight the need for sanitizing commercial jeotgal, and provide evidence to help reduce the risk of jeotgal contamination by antimicrobial-resistant bacteria.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.918-926
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• 2021

We isolated 28 Vibrio vulnificus strains from seawater and fisheries and investigated the positive rate of eight virulence genes. Additionally, we evaluated the susceptibility of these strains to 25 antimicrobials. The positive rates of fur, vvhA, tcp, rtxA, vcgC, viuB, vvp, and acfA were 100, 92.9, 92.9, 67.9, 64.3, 25.0, 14.3, and 7.1%, respectively. A disk diffusion susceptibility test revealed that, all the investigated strains had the highest resistance to amoxicillin and oxacillin, followed by that to streptomycin (96.4%), cefoxitin (92.9%), clindamycin (82.1%), amikacin (67.9%), vancomycin (46.4%), nalidixic acid (7.1%), penicillin G (7.1%), and ampicillin (3.6%). Moreover, they were susceptible to 10 other antimicrobials, including cefotaxime, chloramphenicol, erythromycin, gentamicin, and rifampicin. Notably, amoxicillin, oxacillin, and streptomycin had average minimum inhibitory concentrations of 132.6, 603.4, and 23.1 ㎍/mL against V. vulnificus, respectively. These observations provide new insights regarding the necessity for sanitation of commercial fisheries and can potentially, help reduce the risk posed by fisheries contaminated with bacteria resistant to antimicrobials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.850-857
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• 2022

Seventy-five Vibrio parahaemolyticus isolates from the surface seawater of the Geum River Estuary area, on the west coast of Korea, were analyzed for the presence of virulence genes and susceptibility to 17 different antimicrobials. All 75 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction; Only one of the isolates possessed the tdh or trh gene. According to the results of disk diffusion susceptibility tests, all of the strains were resistant to penicillin G, 92.0% were resistant to ampicillin, 82.7% were resistant to amoxicillin, 2.7% were resistant to ciprofloxacin, 2.7% were resistant to trimethoprim, 1.3% were resistant to cephalothin, and 1.3% were resistant to erythromycin. However, all of the strains were susceptible to amikacin, cefoxitin, chloramphenicol, gentamycin, kanamycin, nalidixic acid, nitrofurantoin, rifampin, streptomycin, and tetracycline. The average minimum inhibitory concentrations for ampicillin for V. parahaemolyticus was 557.6 ㎍/mL. These results not only provide novel insight into the necessity for seawater sanitation in Geum river estuary area, but they help reduce the risk of contamination of antimicrobial-resistant bacteria.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.2
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• pp.86-91
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• 2010

We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

• The Journal of the Korean Society for Microbiology
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• v.35 no.3
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• pp.239-250
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• 2000

Sixty-eight clinical isolates of Stenotrophomonas maltophilia from inpatients of 2 university hospitals in Taegu were epidemiologically analyzed by using the minimum inhibitory concentrations of 25 antimicrobial drugs, biochemical reaction, pulsed-field gel elctropgoresis (PFGE), and PCR with enterobacterial repetitive intergenic consensus sequences as primer (ERIC-PCR). 1. All the strains were susceptible to minocycline. More than 57% were susceptible to sulfisomidine (Su), ciprofloxacin (Ci), Ofloploxacin (Of), nalidixic acid (Na), and chloramphenicol (Cm), and $19{\sim}35%$ to ceftazidime (Cd), trimethoprim (Tp), Ticacillin-clavulanic acid, and cefoperazone-sulbactam. Most isolates were resistant to ${\beta}$-lactam antibiotics such as ampicillin (Ap), carbenicillin (Cb), cefotaxim (Ct), cefoxitin (Cx), and aminoglycosides including gentamicin (Gm), tobramycin (Tb), amikacin (Ak). 2. All the isolates were multiply resistant of 5 to 17 drugs and showed 40 different resistance pattern types. 3. All the strains showed very similar biochemical reactions except ${\beta}$-galactosidase and nitrate reduction test. Fourteen strains selected randomly were classified 10 different pattern type by PFGE and ERIC-PCR. These two methods showed identical result. Four strains isolated from wound in 1994 showed similar MIC pattern and identical API 20NE profile, PFGE, and ERIC-PCR pattern indicating episodes of cross-infection among patients. These results indicate that PFGE or ERIC-PCR profile has comparable discriminatory power for epidemiological typing of S. maltophilia.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.564-572
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• 2016

In this study, we isolated and characterized Escherichia coli from mussels and inland pollution sources in or in proximity to the Changseon area on the southern coast of Korea in 2014. A total of 147 strains of E. coli were isolated from 54 mussels and 32 pollution-source samples. The susceptibility of the isolates to 24 antimicrobial agents was analyzed. The resistance of E. coli isolates to rifampin was highest at 100%, followed by cephalothin (98.6%), tetracycline (91.8%), amikacin (81.0%), ampicillin (79.6%), cefazolin (79.6%), streptomycin (73.5%), piperacillin (70.7%), gentamicin (37.4%), cefoxitin (35.4%), cefamandole (34.7%), tobramycin (29.9%), amoxicillin/clavulanic acid (24.5%), nalidixic acid (21.8%), trimethoprim (19.0%), chloramphenicol (17.7%), cefotaxime (12.9%), trimethoprim (10.9%), ceftazidime (10.2%), aztreonam (7.5%), imipenem (2.7%), cefepime (2.0%), and cefotetan (0.0%). In addition, the antimicrobial resistance of E. coli isolates from inland pollution sources was slightly greater than or similar to that of isolates from mussels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.582-588
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• 2016

Seventy-nine Vibrio parahaemolyticus isolates from surface seawater from Gomso Bay, west coast of Korea, were analyzed for the presence of virulence genes and their susceptibility to 30 different antimicrobials. All 79 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction (PCR); however, no isolates possessed either the tdh or trh gene. According to a disk diffusion susceptibility test, all of the strains studied were resistant to oxacillin, penicillin, and vancomycin, followed by ticarcillin (97.5%), ampicillin (96.2%), clindamycin (86.1%), erythromycin (10.1%), streptomycin (7.6%), cefoxitin (6.3%), amikacin (2.5%), and cephalothin (2.5%). However, all of the strains were susceptible to 19 other antimicrobials including cefepime, cefotaxime, chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. All 79 isolates (100%) were resistant to four or more classes of antimicrobials, and two strains exhibited resistance to eight antimicrobial agents. The average minimum inhibitory concentrations (MICs) for V. parahaemolyticus for ampicillin, penicillin, ticarcillin, and vacomycin were 946.5, 1,305.9, 1,032.3, and 45.0 µg/mL, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.587-595
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• 2019

Eighty-three Vibrio parahaemolyticus isolates from surface seawater in Gomso Bay on the west coast of Korea, and commercial fisheries from Gunsan fisheries center were analyzed for the presence of virulence genes and susceptibility to 30 different antimicrobials. All 83 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction; however, neither gene was found in any of the isolates. A disk diffusion susceptibility test, showed that all of the strains studied were resistant to clindamycin, oxacillin, ticarcillin, and vancomycin, and also revealed varying levels of resistance to ampicillin (98.8%), penicillin G (95.2%), streptomycin (20.5%), cefoxitin (14.5%), amikacin (6.0%), cephalothin (4.8%), and erythromycin (3.6%). However, all of the strains were susceptible to 19 other antimicrobial agents, including cefepime, cefotaxime, chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. All 83 isolates (100%) were resistant to five or more classes of antimicrobials, and two strains exhibited resistance to ten antimicrobial agents. The average minimum inhibitory concentrations against V. parahaemolyticus of clindamycin, oxacillin, ticarcillin, and vancomycin were 55.9, 98.3, 499.3, and 44.3 ㎍/mL, respectively. These results provide new insight into the necessity for seawater sanitation in Gomso Bay and commercial fisheries, and provide evidence to help reduce the risk of contamination by antimicrobial-resistant bacteria.

• The Journal of the Korean Society for Microbiology
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• v.21 no.1
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• pp.17-31
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• 1986

Forty clinical isolates of Serratia marcescens were tested for their susceptibility to 19 antimicrobial drugs and studied on the molecular characteristics of R plasmids. Cefotaxime (Ct) was the most effective drug and only 2 (5%) strains were resistant to this drug. Thirteen to 18% of strains were resistant to cefoperazone (Cz), amikacin (Ak). and trimethoprim (Tp), and 28 to 40% were resistant to piperacillin (Pi), nalidixic acid (Na), gentamicin (Gm), and cefoxitin (Cx). A majority of strains were resistant to carbenicillin (Cb), tobramycin (Tp), kanamycin (Km), and cefamandole (Cd), and all to cephalothin. One half of the isolates were resistant to 10 or more drugs. $MIC_{90}$ of Pi to Gm-resistant strains (Gm') were 8 times higher than that to Gm-susceptible strains (Gm'), but $MIC_{90}$ of Ak, Cx, Ct, and Cz were almost the same between both Gm' and Gm' strains. Nine (23.7%) strains among 38 of multiply drug-resistant S. marcescens transferred conjugally their partial patterns of resistance to E. coli or Klebsiella strains, and two S. marcescens strains producing bacteriocin transferred their resistance to Klebsiella only, but not to E. coli. The plasmid profiles of S. marcescens were studied by the methods of SDS lysis and agarose gel electrophoresis. Twenty-four (60%) strains carried one to four plasmids of 1.4. to 144 Mdal, and conjugative R plasmids of 49 to 127 Mdal were noted in transconjugants. MIC levels of drugs in transconjugants were variable by the R plasmids and recipient strains.

• The Journal of the Korean Society for Microbiology
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• v.22 no.4
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• pp.453-462
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• 1987

A total of 3,879 cases of feces and rectal swab from patient was collected in H. hospital from January 1974 to December 1986 in Seoul. Among the materials, the number of cases of Shigella spp. isolated were 197 strains of 139 patients. Infectous pattern and antibiotic sensitivity of Shigella spp. were as follows; The range of percentage of an identified Shigella spp. among total feces and rectal swabs was $1.5{\sim}12.5%$ yearly. The isolation ratios of Shigella spp. per each patient 1.35 for male and 1.19 for female. The isolation ratio of male to female was 1.28:1 in whole group. The isolated Shigella species was 81.0% in S. flexneri, 1.1% in S. boydii and 17% in S. sonnei. The highest number of Shigella spp. was found in August and September according to monthly isolation, on the other hand the lowest number of Shigella spp. was obserbed in March. The seasonal isolation rate of Shigella spp. was 31.7% in Fall, 27.3% in Summer, 21.6% in Winter and 19.3% in Spring. The age specific frequency of Shigellosis was 46.8% in $0{\sim}9$ year group, 8.6% in $10{\sim}19$, 7.2% in $40{\sim}49$ and 6.5% in $50{\sim}59$. The antibiotics showing over 80% susceptibility against Shigella spp. were gentamicin, kanamycin, amikacin, tobramycin, cefoperazone, cefoxitin, cefamandole nafate, cefotaxine and sisomycin.