Multiple antibiotic resistant Streptococcus agalactiae and Streptococcus iniae in Nile tilapia aquaculture

Abstract

Streptococcosis is a zoonotic bacterial disease in tilapia and other fresh that creates economic losses, caused mainly by Streptococcus agalactiae and Streptococcus iniae. The hazard of the disease is that it may present apparently healthy as well as its presence in culture water. So, this work aimed to detect streptococci in Nile tilapia farms located in Assiut and Minia Governorates, Egypt. Streptococcus agalactiae (42 isolates) and Streptococcus iniae (59 isolates) were identified. Two Streptococcus agalactiae isolates were molecularly confirmed and exhibited resistance to most antibiotics and a multiple antibiotic resistant index of 0.9-1. The identified isolates could not form biofilm. Identification of these hemolytic, resistant Streptococcus poses a potential hazard for human health; hence, alternative antimicrobials should be searched against infections caused by these bacteria.