• 미생물학회지
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• 제43권1호
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• pp.31-39
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• 2007

2000-2004년 국내에서 분리된 S. sonnei 135주를 선별하여 16종의 항균제 내성 유형, $bla_{TEM}$, suulII, tetA, strA등의 내성유전자형을 PCR등의 방법으로 항생제내성 표현형과 유전자형의 유연관계를 파악하였다. 균주들의 생화학적 성상은 전형적 인 이질성 세균의 특성을 나타내었으며, biotyping에서는 g type이 58.5%(79주), a type이 40.0%(54주), e type이 1.5%(2주)로 나타났다. 항균제 16종의 항균제 내성 패턴은 AN, CIP, C, GM등의 약제에는 감수성을 보였으나, SXT 약제에는95.6% (129주), TE 약제에는 93.3% (126주), SM에는 90.4% (122주)등의 순으로 내성을 나타내었다. 두 가지 이상 약제 내성균이 97.8% (132주), 그 중에서 R28 (AM, SAM, TE, TIC, SXT, K, SM, AmC : 8제 약제 내성) 형이 31.1% (42주)를 차지하였으며, 33가지 형태의 다양한 내성 패턴을 나타내었다. $bla_{TEM}$, sulII, tetA 및 strA등의 내성유전자 분포에서는 Disk diffusion법에서 내성을 보인 경우에는 모두 각각의 유전자 증폭산물이 검출되었다.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.974-981
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• 2020

Sequence type 410 (ST410) of Escherichia coli is an extraintestinal pathogen associated with multi drug resistance. In this study, we aimed to investigate the horizontal propagation pathway of a high-risk clone of E. coli ST410 that produces Klebsiella pneumoniae carbapenemase (KPC). blaKPC-encoding E. coli and K. pneumoniae isolates were evaluated, and complete sequencing and comparative analysis of blaKPC-encoding plasmids from E. coli and K. pneumoniae, antimicrobial susceptibility tests, polymerase chain reaction, multilocus sequence typing, and conjugal transfer of plasmids were performed. Whole-genome sequencing was performed for plasmids mediating KPC-2 production in E. coli and K. pneumoniae clinical isolates. Strains E. coli CPEc171209 and K. pneumoniae CPKp171210 were identified as ST410 and ST307, respectively. CPEc171209 harbored five plasmids belonging to serotype O8:H21, which is in the antimicrobial-resistant clade C4/H24. The CPKp171210 isolate harbored three plasmids. Both strains harbored various additional antimicrobial resistance genes. The IncX3 plasmid pECBHS_9_5 harbored blaKPC-2 within a truncated Tn4401a transposon, which also contains blaSHV-182 with duplicated conjugative elements. This plasmid displayed 100% identity with the IncX3 plasmid pKPBHS_10_3 from the K. pneumoniae CPKp171210 ST307 strain. The genes responsible for the conjugal transfer of the IncX3 plasmid included tra/trb clusters and pil genes coding the type IV pilus. ST410 can be transmitted between patients, posing an elevated risk in clinical settings. The emergence of a KPC-producing E. coli strain (ST410) is concerning because the blaKPC-2-bearing plasmids may carry treatment resistance across species barriers. Transgenic translocation occurs among carbapenem-resistant bacteria, which may spread rapidly via horizontal migration.

• 한국수산과학회지
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• 제49권5호
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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.

• 한국동물위생학회지
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• 제46권1호
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• pp.35-45
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• 2023

Pathogenic Escherichia coli is the cause of a wide range of diseases in pigs, including diarrhea, edema disease, and septicemia. Diarrhea caused E. coli may result in significant economic losses, making pathogenic E. coli an important pathogen for the swine industry. This study investigated the prevalence of virulence factor genes, antimicrobial resistance phenotypes, and resistance genes in E. coli isolated from feces of piglets in Korea between 2017 and 2020. As a result, 119 pathogenic E. coli isolates were obtained from 601 fecal samples. The F4 adhesin gene and the STb enterotoxin gene were commonly present in E. coli isolated from diarrhea samples. The dominant virulotypes of isolates from diarrhea samples were STb, Stx2e, and F4:LT:STb. More than 80% of the screened isolates were resistant to ampicillin, sulfisoxazole, chloramphenicol, or tetracycline. To confirm the resistance mechanisms for β-lactam or quinolone, we investigated the genotypic factors of resistance. Each of the ceftiofur-resistant E. coli produced an extended-spectrum β-lactamase encoded by bla_CTX-M-14, bla_CTX-M-27, and bla_CTX-M-55. And all ciprofloxacin-resistant E. coli harbored mutations in quinoloneresistance-determining-regions. In addition, some of the ciprofloxacin-resistant E. coli contained the plasmid-mediated-quinolone-resistance genes such as qepA, qnrB1, or qnrD. This study has confirmed that the F4 fimbria and the STb enterotoxin are the most predominant in pathogenic E. coli isolated from piglets with diarrhea in Korea and there is a great need for responsible and prudent use of antimicrobials to treat colibacillosis.

• 한국미생물·생명공학회지
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• 제51권3호
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• pp.268-279
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• 2023

The pharmaceutical industry in Bangladesh produces a diverse range of antibiotics for human and animal use, however, waste disposal management is inadequate. This results in substantial quantities of antibiotics being discharged into water bodies, which provide suitable environment for the growth of antibiotic-resistant bacteria, capable of spreading resistance genes. This study intended for exploring the bacterial antibiotic resistance profile in adjoining aquatic environmental sources of pharmaceutical manufacturing facilities in Bangladesh. Seven surface water samples were collected from the vicinity of two pharmaceutical industries located in the Savar area and 51 Escherichia coli isolates were identified using both phenotypic and genotypic methods. Antibiotic susceptibility tests revealed the highest percentage of resistance against ampicillin, azithromycin, and nalidixic acid (100%) and the lowest resistance against meropenem (1.96%) out of sixteen different antibiotics tested. 100% of the study E. coli isolates were observed with Multidrug resistance phenotypes, with the Multiple Antibiotic Resistance (MAR) value ranging from 0.6-1.0. Furthermore, 69% of the isolates were Extended Spectrum Beta-Lactamases (ESBL) positive as per the Double Disk Diffusion Synergy Test (DDST). ESBL resistance genes bla_TEM, bla_CTX-M-13, bla_CTX-M-15, and bla_SHV were detected in 70.6% (n = 36), 60.8% (n = 32), 54.9% (n = 28), and 1.96% (n = 1) of the isolates, respectively, by Polymerase Chain Reaction (PCR). Additionally, 15.68% (n = 8) of the isolates were positive for E. coli specific virulence genes in PCR. These findings suggest that pharmaceutical wastewater, if not properly treated, could be a formidable source of antibiotic resistance spread in the surrounding aquatic environment. Therefore, continued surveillance for drug resistance among bacterial populations around drug manufacturing facilities in Bangladesh is necessary, along with proper waste disposal management.

• 대한임상검사과학회지
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• 제48권4호
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• pp.327-334
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• 2016

최근 사람과 가축에 항균제의 과도한 사용으로 감염병을 일으키는 병원성 세균들의 항균제 내성이 증가하고 있다. 본 연구에서는 PCR과 염기서열분석법을 이용하여 충청지역 일개의 대학병원에 의뢰된 임상검체와 같은 지역에서 사육된 닭으로부터 분리된 P. mirabilis 균주를 대상으로 16S ribosomal RNA methyltransferase(RMTase) 유전자와 integron을 조사하였다. 또한 Repetitive extragenic palindromic sequence-based PCR (REP-PCR)을 이용하여 P. mirabilis 균주들의 역학적 연관성 조사하였다. 총 38균주의 P. mirabilis 중에서 임상검체로부터 분리된 7균주 (18.4%)만이 RMTases 유전자를 가지고 있었는데 이들은 모두 amikacin, tobramycin, 및 gentamicin에 내성을 나타냈다. 또한 대상균주 중 23균주(60.5%)가 class 1 integron을 가지고 있는 것으로 나타났으며 class 2 및 class 3 integron은 검출되지 않았다. 본 연구에서 확인된 integrons에는 aminoglycoside 내성유전자(aadA2, aadA5, aadA7, 및 aacCA5), ${\beta}$-lactmam 내성유전자($bla_{PSE}$), erythromycin 내성유전자(ereA), lincosamides 내성유전자(linF), 및 trimethoprim 내성유전자(dfrA12, dfrA17 및 dfrA32)등이 유전자 카세트로 포함되어 있었다. 본 연구결과 RMTase 유전자는 임상검체로부터 분리된 P. mirabilis 균주에만 확산되어 있었던 반면 class 1 integrons는 임상검체와 닭으로부터 분리된 P. mirabilis 균주에 광범위하게 확산되어 있음을 확인할 수 있었다. 게다가 닭으로부터 분리된 균주 중에는 동일한 REP-PCR 밴드패턴을 보인 균주들이 있었는데 이는 닭들 사이에서 P. mirabilis 균주가 수평확산 되었음을 의미한다. P. mirabilis 균주에서 항균제 내성유전자의 확산을 막기 위해서는 내성유전자 지속적인 모니터링과 감시가 필요할 것으로 사료된다.

• 한국동물위생학회지
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• 제36권3호
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• pp.171-180
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• 2013

This study was carried out to investigate the antimicrobial resistance pattern and distribution of resistance gene in 44 Enterobacteriaceae and 21 Pseudomonas (P) aeruginosa isolated from hospitalized dogs and cats in animal hospital from 2010 to 2011 in Daegu. Among Enterobacteriaceae, Escherichia (E) coli was highly resistant to ampicillin (56.7%), followed by tetracycline (53.3%), cephalothin, streptomycine, sulfamethoxazole/trimethoprim, gentamicin and norfloxacin (40.0~43.3%). The remaining isolates of Enterobacteriaceae had high resistance to ampicillin (64.3%) and streptomycin (42.9%). Whereas, P. aeruginosa was low resistant to all antimicrobials tested (less than 15%). int I 1 gene was detected in 20 (57.1%) of 35 antimicrobial resistant Enterobacteriaceae and 2 (9.5%) of 21 P. aeruginosa., but int I 2 gene was not detected in all isolates. The eight resistance genes were found either alone or combination with other gene (s): $bla_{TEM}$, aadA, strA-strB, clmA, tetA, tetB, sul I and sul II. About 78% of integron-positive isolates were resistance to more than four antimicrobial agents. The findings suggest that class I integrons are widely distributed in E. coli among Enterobacteriaceae from dogs and cats and multi-drug resistance related to the presence of class I integrons. The prudent use of antimicrobials and continuous monitoring for companion animals are required.

• 한국수산과학회지
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• 제54권6호
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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.

• 한국수산과학회지
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• 제53권6호
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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.

• 대한임상검사과학회지
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• 제50권2호
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• pp.100-109
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• 2018

다제내성(multidrug-resistant, MDR) Acinetobacter baumannii 균주의 출현 및 확산이 전 세계적으로 보고되어 왔는데, 이들 대부분은 생물막 형성능력을 가지고 있다. 생물막 형성은 소독 및 건조에 대해 세균이 저항할 수 있도록 해주는 중요한 병독성 인자이다. 본 연구에서는 생물막을 형성하는 A. baumannii 임상 분리주를 대상으로 항균제 내성 기전에 대한 유전적 기초를 조사하였다. 크리스탈 바이올렛 분석법을 통해 생물막 형성능력을 확인한 결과 46균주가 생물막을 형성하는 것으로 나타났다. 이어서 REP-PCR을 수행하여 서로 다른 클론에 속하는 16 균주를 선택한 후 이 균주들을 대상으로 항균제 내성 인자를 검출하였다. 본 연구에서 분리된 9개 non-MDR (0.96) 균주와 7개의 MDR (1.05) 균주의 평균 생물량은 서로 달랐지만, 이 차이는 유의하지 않았다. 대부분의 생물막 형성 MDR 균주는 다양한 항균제 내성인자 ($bla_{OXA-23}$, armA 및 gyrA 및 parC의 돌연변이)를 가지고 있는 것으로 나타났다. 그러나 대부분의 non-MDR 균주는 항균제 내성인자를 포함하지 않는 것으로 나타났다. 우리의 결과는 A. baumannii 균주의 생물막 형성능력이 항균제 감수성과 상관관계가 적음을 시사한다. 또한 MDR A. baumannii 임상 분리주의 출현은 대개 항균제 내성과 관련된 유전자의 돌연변이나 또는 다양한 항균제 내성인자의 획득에 의한 것으로 사료된다.