title: First description of 'Chalky back' phenomenon in banana prawns (Fenneropenaeus merguiensis) and its possible association with Vibrio and Photobacterium species.
abstract: Here we report a newly identified 'Chalky back' phenomenon in banana prawns (Fenneropenaeus merguiensis) farmed in North Queensland, Australia. This was characterized by localized white discoloured segmentation of the cervical groove, moreover, after cooking the prawns exploded, making them unfit for commercial sale. Histological examination revealed breakdown of gut and abdominal muscle tissue in some moribund specimens. We selectively isolated Vibrio spp., which are known prawn pathogens, from healthy and Chalky back specimens. Isolated bacteria were identified, typed and tested for the presence of eight virulence genes (VGs), biofilm formation, adherence and cytotoxicity to fish cells. In all, 32 isolates were recovered and identified as Vibrio harveyi, V. owensii, V. sinaloensis-like, V. campbellii, V. shilonii, Vibrio sp. and Photobacterium damselae using 16S rRNA gene sequencing. All V. harveyi carried VGs coding for haemolysin, toxR and flagella; formed biofilm; and adhered to both cell lines. This was similar to the V. sinaloensis-like strains that were only isolated from Chalky back specimens. Our data suggest that Vibrio spp. may play a role in the pathogenesis of Chalky back. This study is the first report of Chalky back phenomenon in farmed banana prawns that needs to be closely monitored by the industry.
authors.affiliation: Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: Eva
authors.initials: E
authors.lastname: Hatje
authors.affiliation: Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: Giusi
authors.initials: G
authors.lastname: Minniti
authors.affiliation: Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stewart
authors.affiliation: Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: Christina
authors.initials: C
authors.lastname: Neuman
authors.affiliation: Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: Wayne
authors.initials: W
authors.lastname: Knibb
authors.affiliation: Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia mkatouli@usc.edu.au.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Katouli
mesh_terms: D000818:Animals; D017756:Aquaculture; D001315:Australia; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D018441:Biofilms / Q000254:growth & development; D004268:DNA-Binding Proteins / Q000235:genetics; D005407:Flagella / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics; D054884:Host-Pathogen Interactions; D033561:Penaeidae / Q000033:anatomy & histology / Q000382:microbiology*; D010776:Photobacterium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014733:Vibrio / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006460:Hemolysin Proteins; D012336:RNA, Ribosomal, 16S; D014157:Transcription Factors; C066719:toxR protein, bacteria
keywords: Chalky back; Photobacterium spp.; Vibrio spp.; prawns; virulence