Development of Streptococcus agalactiae vaccines for tilapia

Abstract

Vaccination is a widely accepted and effective method to prevent most pathogenic diseases in aquaculture. Various species of tilapia, especially Nile tilapia Oreochromis niloticus, are farmed worldwide because of their high consumer demand. Recently, the tilapia-breeding industry has been hampered by outbreaks of Streptococcus agalactiae infection, which cause high mortality and huge economic losses. Many researchers have attempted to develop effective S. agalactiae vaccines for tilapia. This review provides a summary of the different kinds of S. agalactiae vaccines for tilapia that have been developed recently. Among the various vaccine types, inactivated S. agalactiae vaccines showed superior protection efficiency when compared with live attenuated, recombinant and DNA vaccines. With respect to vaccination method, injecting the vaccine into tilapia provided the most effective immunoprotection. Freund's incomplete adjuvant appeared to be suitable for tilapia vaccines. Other factors, such as immunization duration and number, fish size and challenge dose, also influenced the vaccine efficacy.

Development of attenuated erythromycin‐resistant Streptococcus agalactiae vaccine for tilapia (Oreochromis niloticus) culture

“…It can stimulate organisms to induce effective cell‐mediated and antibody‐mediated immunity on the premise of avoiding pathogenicity and often provide lifelong immunity at low doses. Furthermore, live vaccines are relatively low cost and easy to apply (Frey, ; Liu et al, ). In order to develop attenuated bacteria via selection of resistance to chemicals, erythromycin was used in this study, and an erythromycin‐resistant S. agalactiae strain (TFJ‐ery) was isolated from the natural low‐virulence strain TFJ0901.…”

“…The marker (M) sizes were 2,000, 1,000, 750, 500, 250 and 100 bp, respectively. Lanes 1 and 2 were TFJ0901 and TFJ-ery, respectively Furthermore, live vaccines are relatively low cost and easy to apply (Frey, 2007;Liu et al, 2016). In order to develop attenuated bacteria via selection of resistance to chemicals, erythromycin was used in this study, and an erythromycin-resistant S. agalactiae strain (TFJery) was isolated from the natural low-virulence strain TFJ0901.…”

“…However, the widespread use of antibiotics promotes the spread of antibiotic resistance and causes an imbalance of bacterial microbiota in fish tracts or in the habitat (Yousefian & Amiri, ). Vaccination has been established as an effective method in preventing streptococcosis in fish (Liu et al, ). Traditional inactivated vaccines composed of formalin‐killed whole S. agalactiae cells and concentrated extracellular products (ECP) were used widely to provide protection for tilapia from S. agalactiae infection (Evans, Klesius, & Shoemaker, ; Pasnik, Evans, & Klesius, ; Pasnik, Evans, Panangala et al, ).…”

Galleria mellonellaas an infection model for the multi-host pathogenStreptococcus agalactiaereflects hypervirulence of ST283

“…In 1966, GBS infection of fish was reported in the USA 2 with subsequent outbreaks described in fish farms in Asia and the Americas 3,4 . GBS infection is often associated with high levels of mortality in fish and with the worldwide growth of aquaculture has significant economic impact 5 . In the 1970s GBS was described as the leading cause of human neonatal infectious morbidity and mortality with two distinct GBS-associated syndromes: earlyonset disease occurring 0-6 days after birth and late-onset disease occurring 7 days -3 months after birth 6,7 .…”

Analysis of Streptococcus agalactiae ‐induced liver injury in tilapia ( Oreochromis niloticus )

“…| 1399 DU et al to study the pathogenesis of streptococcus in fish (Yamamoto et al, 1999). It has been reported that the main pathogens of tilapia infection are Streptococcus agalactiae and Streptococcus dolphinis (Liu et al, 2016). Another study reported that the main pathogen isolated from infected tilapia after 2008 was S. agalactiae (Lusiastuti, Textor, Seeger, Akineden, & Zschöck, 2014).…”