• 대한수의학회지
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• 제62권1호
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• pp.4.1-4.5
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• 2022

This paper describes a fatal case of pneumonia in a 14-day-old dog caused by extraintestinal pathogenic Escherichia coli (ExPEC). The necropsy showed that almost all of left lobes of the lungs had dark-red consolidation. A histopathology examination revealed moderate acute fibrino-hemorrhagic necrotizing pneumonia with intralesional bacterial colonies. Non-suppurative epicarditis, congestion in the liver, and necrosis in the white pulp of the spleen also were found. E. coli with cytotoxic necrotizing factor 1 and α-hemolysin was isolated from the lung. This case was confirmed to have fatal pneumonia caused by ExPEC that led to a systemic infection.

• 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.

• 대한수의학회지
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• 제53권3호
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• pp.163-167
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• 2013

Avian pathogenic Escherichia coli (APEC) are known to cause extraintestinal disease in poultry, leading to substantial losses in the industry. IutA, iron-regulated aerobactin receptor is firmly associated with APEC. To assess the potential of IutA to induce protective immune responses, attenuated Salmonella Typhimurium strain expressing IutA was constructed and administered orally to BALB/c mice. The IutA-specific immune responses were measured with sera, vaginal and fecal samples by an enzyme-linked immunosorbent assay. We found that the Salmonella-IutA vaccine induced significantly higher immune responses as compared to the control inoculated with the attenuated S. Typhimurium containing the plasmid only. The IutA-specific immune responses were increased by second immunization at third week after initial immunization, whereas triple immunization induced lower immune responses than those induced by the double immunization. The Salmonella-IutA vaccine induced a nature of immunity biased to the Th1-type, as judged by the ratio of IutA-specific IgG isotypes (IgG2a/IgG1). Overall, these results suggest that the Salmonella-IutA vaccine appear to be suitable candidate for a vaccine against APEC.

• 한국임상수의학회지
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• 제28권3호
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• pp.297-302
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• 2011

조류병원성 대장균 (APEC)은 가금에서 많은 장관외 질병을 야기한다. 병원성 인자 중 하나인 P-fimbriae 또한 질병과 밀접하게 관련되어 있다. 이번 연구에서 마우스에 P-fimbriae의 subunit 들인 PapA와 PapG를 발현하는 재조합 약독화 Salmonella Typhimurium 백신균주 접종 후 APEC 방어에 필요한 면역반응 유도 여부를 알아보기 위한 실험을 수행하였다. 각 백신 균주로 경구 접종 후 각 항원에 대한 serum IgG 항체 역가는 접종 후 4주째부터 대조군에 비해 항체 역가가 높게 유도되기 시작하여 실험이 끝날 때까지 높은 항체 역가가 계속 유지 되었다. 한번 접종 된 경우보다 추가 접종 된 군에서 보다 높은 항체 역가가 관찰되었다. 더불어 각 항원에 대한 mucosal IgA 역가 또한 높게 유도되었다. 두 균주를 혼합하여 접종 하였을 경우에는 각 백신 균주를 접종하였을 경우보다 높은 serum IgG와 mucosal IgA의 역가가 관찰되었다. 이 결과는 이들 백신 균주가 면역원성이 있음을 확인하는 결과였다. 또한 helper T cells type을 알아보기 위해 IgG1과 IgG2a의 항체 역가를 측정하여 본 결과 각 백신 균주를 접종하였을 경우에는 IgG2a의 항체 역가가 IgG1의 항체 역가 보다 월등히 높은 이들 백신 균주를 접종 하였을 경우에는 Th1-type의 면역 반응이 유도되지만 두 백신 균주를 혼합 접종하였을 경우에는 Th1-과 Th2-type 모두를 유도하는 것으로 관찰되었다. 이 결과를 통해서 이들 두 백신 균주를 혼합 접종 하였을 경우에는 세포성 면역뿐만 아니라 체액성 면역 모두를 유도할 수 있음을 확인할 수 있었다.