Abstract
BackgroundThe present investigation was an endeavor into the elucidation of the disease-causing pathogen of streptococcosis in Nile tilapia (Oreochromis niloticus) in Egypt affecting adult fish cultured and wild fish in the Nile river. Fish were obtained from commercial fishermen, collected as part of their routine fishing activities. The researchers observed the routine fishing process and selected fish for use in the study, at the point of purchase from the fisherman.ResultsDiseased fish showed exophthalmia with accumulation of purulent and haemorrhagic fluid around eyes, and ventral petechial haemorrhages. The Post mortem examination revealed, abdominal fat haemorrhage, pericarditis and enlargement of the liver, spleen and kidney. Gram-stained smears revealed the presence of Gram-positive cocci, β-hemolytic, oxidase and catalase negative. Analysis of the 16S rRNA gene confirmed that the 17 tilapia isolates studied were 6/17 Enterococcus faecalis, 2/17 Enterococcus gallinarum, 3/17 Streptococcus pluranimalium, 2/17 Aerococcus viridans, 1/17 isolate of each Streptococcus dysgalactiae, Streptococcus anginosus, Lactococcus garvieae and Granulicetella elegans/Leuconostoc mesenteroides cremoris. It should be noted that there was no mixed infection. Multiple resistance was observed and the most frequent antibiotic combination was penicillin, ampicillin, vancomycin, chloramphenicol, rifampicin, ofloxacin, clindamycin, erythromycin and tetracycline representing eight classes.ConclusionsConsequently, we concluded that Streptococcus species are an emerging pathogen for Nile tilapia aquaculture in Egypt and to be considered as a new candidate in the warm water fish diseases in Egypt with special reference to L. garvieae, S. dysgalactiae in addition to L. mesenteroides cremoris which was not reported before from tilapia and taking into consideration their zoonotic implications for public health.
Highlights
The present investigation was an endeavor into the elucidation of the disease-causing pathogen of streptococcosis in Nile tilapia (Oreochromis niloticus) in Egypt affecting adult fish cultured and wild fish in the Nile river
With a production capacity of 806,000 Metric tons (MT) represents almost 50% of the total global production positioned itself as the largest Nile tilapia producer, with Egypt to follow with 200,000 MT, the Philippines with 111,000 MT, Thailand with 97,000 MT and Indonesia with 72,000 MT
The present investigation was an endeavor into the elucidation of the disease-causing pathogen of streptococcosis in Nile tilapia (O. niloticus) in Egypt affecting adult fish cultured and wild fish in the Nile river by studying the phenotypic, antibiotic resistance and molecular characterization of the streptococcal strains isolated from Nile tilapia demonstrating septicemia
Summary
The present investigation was an endeavor into the elucidation of the disease-causing pathogen of streptococcosis in Nile tilapia (Oreochromis niloticus) in Egypt affecting adult fish cultured and wild fish in the Nile river. The common name Nile tilapia (Oreochromis niloticus) is a species of Tilapia (Oreochromis sp.) which in turn is the regular name for about a hundred species of cichlid fish from the tilapiine cichlid lineage [1]. They are freshwater fish species, local to Africa and Middle East areas [2], and the third biggest group of bony fish. With a production capacity of 806,000 MT represents almost 50% of the total global production positioned itself as the largest Nile tilapia producer, with Egypt to follow with 200,000 MT, the Philippines with 111,000 MT, Thailand with 97,000 MT and Indonesia with 72,000 MT. Significant quantities of tilapia are produced annually by Cuba, Israel, Malaysia, the USA, Viet Nam and Zimbabwe, yet it should be noted that, their production is reported to FAO as ‘tilapias nei’ (which may include other tilapia species) and ‘freshwater fishes nei’ [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
