IDENTIFICATION OFFRANCISELLA NOATUNENSISIN NOVEL HOST SPECIES FRENCH GRUNT (HAEMULON FLAVOLINEATUM) AND CAESAR GRUNT (HAEMULON CARBONARIUM)

Abstract

Francisella noatunensis is an emerging pathogen of fish that has been isolated from several cultured species worldwide. Here presented is a case involving several hundred marine grunts that were caught near the Florida Keys for display in public aquaria. These fish were maintained in a recirculating system where they began to experience mortalities approximately two weeks post-stocking. Postmortem examination revealed disseminated systemic granulomatous disease most severely affecting spleen and kidney. Splenic and renal tissue homogenates inoculated in modified Thayer Martin agar media yielded colonies consistent with F. noatunensis 4 days post inoculation. Bacterial colonies and tissues were confirmed positive after real-time PCR amplification of the intracellular growth loci gene (iglC) specific for F. noatunensis subspecies orientalis. Consequently, multiple novel host species for this pathogen were identified, including the French grunt (Haemulon flavolineatum) and the Caesar grunt (Haemulon carbonarium).

Molecular characterization and pathogenicity of Francisella noatunensis subsp. orientalis isolated from cultured tilapia (Oreochromis sp.) in Taiwan

“…The aetiologic agent of tilapia francisellosis is a Gram‐negative facultative intracellular bacterium belonging to F. noatunensis subsp. orientalis ( Fno ) (synonym F. Asiatica) (Mikalsen & Colquhoun, ) which has also been reported in ornamental cichlids (Hsieh, Wu, Tung, & Tsai, ), three‐line grunt ( Parapristipoma trilineatum ) (Kamaishi et al, ), hybrid striped bass ( Morone chrysops x M. Saxatilis ) (Ostland et al, ), ornamental marine grunts or French grunt ( Haemulon flavolineatum ) and Caesar grunt ( Haemulon carbonarium ) (Soto et al, ). The infected fish reveals multiple‐organ granuloma especially in the head kidney and spleen, resulting in high morbidity with variable mortality and non‐specific clinical signs such as anorexia, exophthalmia and anaemia.…”

“…Caesar grunt (Haemulon carbonarium) (Soto et al, 2014). The infected fish reveals multiple-organ granuloma especially in the head kidney and spleen, resulting in high morbidity with variable mortality and non-specific clinical signs such as anorexia, exophthalmia and anaemia.…”

Improved Broth Microdilution Method for Antimicrobial Susceptibility Testing ofFrancisella Noatunensis Orientalis

“…Some isolates were generously shared by Dr. John Hansen from the Interdisciplinary Program in Pathobiology, University of Washington, Seattle, and Dr. Duncan J. Colquhoun at the Section for Bacteriology, Norwegian Veterinary Institute, Oslo. The identity of all isolates was confirmed using a quantitative real-time PCR assay for the detection of the iglC gene of F. noatunensis orientalis (Soto et al 2011(Soto et al , 2014.…”

“…Bacteria.-The strains of F. noatunensis orientalis used in this study were isolated from a wide range of fish species and geographical locations ( Table 1). Some of the isolates have been described previously (Kamaishi et al 2005;Soto et al 2009Soto et al , 2011Soto et al , 2012Soto et al , 2013bSoto et al , 2014Vojtech et al 2009;Jeffery et al 2010). Some isolates were generously shared by Dr. John Hansen from the Interdisciplinary Program in Pathobiology, University of Washington, Seattle, and Dr. Duncan J. Colquhoun at the Section for Bacteriology, Norwegian Veterinary Institute, Oslo.…”

“…During the past 10 years, F. noatunensis orientalis has been implicated as the cause of mortalities in tilapia Oreochromis spp. and other important warmwater species cultured worldwide (Mauel et al 2003;Kamaishi et al 2005;Soto et al 2009Soto et al , 2011Soto et al , 2013bSoto et al , 2014Jeffery et al 2010;Colquhoun and Duodu 2011). In tilapia the diseases can be observed as an acute syndrome with few clinical signs and high mortality or as a subacute to chronic syndrome with nonspecific clinical signs like anorexia, exophthalmia, and anemia.…”