Roles of thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) in Vibrio parahaemolyticus

Abstract

Vibrio parahaemolyticus is the leading cause of seafood borne bacterial gastroenteritis in the world, often associated with the consumption of raw or undercooked seafood. However, not all strains of V. parahaemolyticus are pathogenic. The thermostable direct hemolysin (TDH) or TDH-related hemolysin (TRH) encoded by tdh and trh genes, respectively, are considered major virulence factors in V. parahaemolyticus. However, about 10% of clinical strains do not contain tdh and/or trh. Environmental isolates of V. parahaemolyticus lacking tdh and/or trh are also highly cytotoxic to human gastrointestinal cells. Even in the absence of these hemolysins, V. parahaemolyticus remains pathogenic indicating other virulence factors exist. This mini review aims at discussing the possible roles of tdh and trh genes in clinical and environmental isolates of V. parahaemolyticus.

Genomic evidence of adaptive evolution in emergent Vibrio parahaemolyticus ecotypes

“…Those strains that do cause illness often carry genes encoding hemolytic exotoxins such as the thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) (Shirai et al, 1990), which cause fluid loss across host cell membranes (Raimondi et al, 2000;Matsuda et al, 2010). Detection of the tdh and trh genes is a test frequently used to identify potentially virulent strains (Bej et al, 1999) although some virulent strains lack both hemolysins (Raghunath, 2014). The mechanism of pathogenesis is also associated with the secretion of effector proteins by a type III secretion system (T3SS) responsible for toxicity in various in vitro and in Elementa: Science of the Anthropocene • 4: 000117 • doi: 10.12952/journal.elementa.000117 vivo models (Burdette et al, 2008;Hiyoshi et al, 2010;Ham and Orth, 2012).…”

RESISTENSI ANTIBIOTIK PADA Vibrio parahaemolyticus DARI UDANG VANAME ASAL PANTAI UTARA JAWA UNTUK PASAR EKSPOR

“…Sementara Yano et al (2014) menemukan V. parahaemolyticus di lingkungan tambak udang resisten terhadap ampisilin dan oksitetrasiklin (72% dan 3%). Resistensi antibiotik dilaporkan terjadi pada beberapa spesies Vibrio di antaranya Vibrio cholera, V. harveyi, V. parahaemolyticus, V. vulnificus, V. fluvialis dan V. campbelli (Kang, Kim, Oh, Mok, & Cho, 2014;QuirozGuzman, Balcazar, Azquez-Juarez, Cruz-Villacorta, & Martínez-Díaz, 2013;Reboucas et al, 2011;Wang et al, 2015;Yano et al, 2014). Penggunaan senyawa antibiotik secara luas pada budidaya udang juga dapat menghasilkan infeksi pada manusia dan berpengaruh terhadap kesehatan manusia (European Federation of Animal Health, 1998;WHO, 2001 (Sunorita & Tjarsono, 2014).…”

“…Profil resistensi antibiotik isolat V. parahaemolyticus dari udang tambak pada musim hujan monsoon) diduga disebabkan oleh jumlahnya yang lebih melimpah. Sebaliknya strain dari sampel musim panas bersifat lebih sensitif terhadap kondisi lingkungan dan lebih cepat menjadi non-culturable sehingga menjadi sulit diisolasi (Raghunath, 2015). Secara keseluruhan isolat bakteri yang diuji resisten terhadap 6 antibiotik (doksisikl in, nitrofurantoin, asam nalidiksat, amoksisilin-asam klavulanat, streptomisin dan eritromisin) dari 8 antibiotik yang diperiksa (Gambar 1, Tabel 4 dan Tabel 5).…”

First multi-year retrospective study on Vibrio parahaemolyticus and Vibrio vulnificus prevalence in Ruditapes philippinarum in Sacca di Goro, Italy

“…Most environmental V. parahaemolyticus strains are considered to be nonpathogenic due to low detection frequencies of tdh and trh genes encoding respectively for the thermostable direct haemolysin (TDH) and the TDH-related haemolysin (TRH), therefore these gene markers continues to be the simplest and most frequently used diagnostic indicator of pathogenicity (Gutierrez West et al , 2013; Raghunath, 2015). …”