1

Speaker(s)：

Shao-Hui Cheng

Topic

Antimicrobial susceptibility of Edwardsiella tarda and Photobacterium damselae isolated from aquatic animals

Abstract

The objective of the present study was to collect Edwardsiella tarda and Photobacterium damselae which were isolated from healthy or diseased aquatic animals in Chiayi, Pingtung, Taitung, Tainan, Penghu, Keelung, and New Taipei City, and to investigate their susceptibility to antimicrobial compounds. Thirty-four isolates including E. tarda (16) and P. damselae (18) were collected. A disk diffusion assay was used and minimum inhibitory concentrations (MIC) were calculated in order to determine the antibiogram of the isolates. Over 88.9% of all isolates were sensitive to most of the approved antimicrobials used in aquaculture. In E. tarda isolates, 69% of isolates were sensitive to doxycycline and oxytetracycline (11/16) and 56.2% of isolates were sensitive to tetracycline (9/16); In P. damselae isolates, 66.7% of isolates were sensitive to oxytetracycline and tetracycline (12/18). PCR amplification conducted on these isolates resulted in the detection of the tetracycline resistance genes tetA-E, tetM, tetS, tetG, tetY as well as genes responsible for resistance to beta-lactam drugs (blaSHV, blaTEM, blaCTX). Detection of a class 1 integron was performed on a SXT resistant isolate of E. tarda by PCR. The results showed that all isolates resistant to tetracycline had at least one tetracycline resistant determinant while blaTEM was detected in 1 isolate of E. tarda. A class 1 integron was also found in 1 isolate of E. tarda which carried a 1.2kb-cassette (dfrA1-orfC). The present study indicated that E. tarda and P. damselae isolates from aquatic animals possess an acceptable level of sensitivity to most of the approved antimicrobials used in aquaculture, with some of them showing moderate resistance to tetracycline.

2

Speaker(s)：

Shu-Chia Hu

Topic

Lyssavirus and rabies virus antibody monitoring of Taiwanese bats

Abstract

The genus Lyssavirus is divided into 14 species, and rabies virus belongs to genotype 1. Lyssavirus can infect a variety of mammalian, causing rabies and rabies-like clinical signs. Bats have been demonstrated that can be the reservoirs of lyssavirus. Animal Health Research Institute (AHRI) has conducted the bat lyssavirus survey project since 2008. A total of 85 bat brain samples of 6 species, including Pipistrellus, Pipistrellus abramus, Eptesicus, Murina puta, Hipposideros armiger terasensis, Scotophilus kuhlii, Miniopterus schreibersii were collected in this year. The direct fluorescent antibody test (dFA) was used to check the presence of lyssavirus antigen, and all samples showed negative result. Twelve samples of oral swabs and feces were collected and were negative via RT-PCR detection for lyssavirus nucleic acid. The collected bat sera through 2008~2014 were transported to USA for rabies antibody detection in cooperation with CDC, USA in 2015. A total of 94 bat sera were detected negative of rabies antibody via micro RFFIT with CVS-11 challenged in USA. The micro RFFIT technique was established in AHRI after the training courses, and the remained bat sera were tested in our laboratory in 2015. Total 165 samples were negative of rabies antibody via micro RFFIT, and 9 samples were waiting for repeat test due to the poorly cell growth or cell death induced by sera toxicity.

3

Speaker(s)：

Ling-Chu Hung

Topic

Differential recognition of capsid protein from PCV2a and PCV2b

Abstract

Porcine circovirus 2 (PCV2) is a small, non-enveloped virus with a single-stranded circular DNA genome that has had severe impacts within the hog industry. Currently, two major genotypes of PCV2 have been recognized, PCV2a and PCV2b. PCV2b has been more frequently isolated from pigs with PCV-associated diseases (PCVAD) and may be a more virulent genotype than PCV2a. The purpose of this study was to generate antibodies anti ORF2 protein (capsid protein) of PCV2 and developing an antigen-capture enzyme- linked immunosorbent assay (AC-ELISA) kits which can detect capsid proteins from PCV2a or PCV2b. Therefore, I generated couples of monoclonal antibodies (mAbs) for PCV2a and PCV2b, respectively. The isotype of the produced mAbs was determined using a ClonotypingTM System. The reactivity of the mAbs to PCV2 capsid protein was determined in a Western blot assay. Some mAb gave a strong and specific reaction with proteins of approximately 27 kDa and 30 kDa. For some mAb, faint but specific bands were observed at 27 kDa, 30 kDa, and 60 kDa respectively. Furthermore, the specificity of mAbs showed positive signals on PCV2 infected swine lymphocytes and in Porcine Circovirus FA substrate slides (VMRD, USA) by indirect immunofluorescence staining. Moreover, we were able to detect different PCV2 capsid proteins with AC-ELISA in PCV2a based vaccine samples, PCV2b ORF2 recombinant protein, and pig whole blood samples. This study demonstrates that these home-made kits can detect capsid proteins from PCV2a or PCV2b.

4

Speaker(s)：

Yu-Hua Shih

Topic

Report on a visit to the Animal and Plant Quarantine Agency of South Korea and Seoul National University

Abstract

Duck viral hepatitis (DVH) is an important waterfowl disease, causing significant economic losses worldwide. The Animal Health Research Institute (AHRI) plans to apply for certification as a World Organization for Animal Health (OIE) reference laboratory for DVH. By visiting the College of Veterinary Medicine, Seoul National University and the Animal and Plant Quarantine Agency (QIA) of South Korea, we have learned essentials for the operation and maintenance of a OIE reference laboratory, and also realized the obligations and commissions of an OIE laboratory. In addition, AHRI needs to enhance close cooperation with neighboring countries, and to further understand the epidemic situation of target diseases for an OIE laboratory. In addition to the hands-on experiences and technical exchanges learned from the OIE laboratory in South Korea, we had the opportunity to gain valuable insights into the international pandemic situation of DVH and built international cooperation during this trip. These are all extremely helpful for the OIE reference laboratory application and for further vaccine development at AHRI.