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1.
J Am Mosq Control Assoc ; 35(3): 220-223, 2019 09.
Article in English | MEDLINE | ID: mdl-31647704

ABSTRACT

An arbovirus surveillance military exercise was conducted to assess the risk of Ross River virus (RRV) and Barmah Forest virus (BFV) in the Australian Defence Force (ADF) Wide Bay training area (WBTA), northeastern Australia, in April 2018. Of the 5,540 female mosquitoes collected, 3,702 were screened for RRV and BFV by quantitative reverse transcription-polymerase chain reaction in a field laboratory. One pool of Verrallina funerea was positive for RRV and 8 pools (7 pools of Aedes vigilax and 1 pool of Culex annulirostris) were positive for BFV. Phylogenetic analysis of the complete nucleotide sequence of the E2 protein subgrouped both RRV and BFV with viruses previously isolated from human infections, indicating the potential risk of RRV and BFV infection to ADF personnel while training in WBTA. This is the 1st time that both RRV and BFV have been detected in a military training area.


Subject(s)
Alphavirus/isolation & purification , Culicidae/virology , Ross River virus/isolation & purification , Alphavirus/genetics , Animals , Female , Military Personnel , Population Surveillance , Queensland , Ross River virus/genetics
2.
Can J Microbiol ; 62(3): 233-40, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26854365

ABSTRACT

We investigated a collection of Pseudomonas aeruginosa strains from hospitalised patients (n = 20) and various environmental sources (n = 214) for their genetic relatedness; virulence properties; antibiotic resistance; and interaction with intestinal (Caco-2), renal (A-498), and lung (Calu-3) cell lines. Using RAPD-PCR, we found high diversity among the strains irrespective of their sources, with only 6 common (C) types containing strains from both a clinical and environmental source. Environmental strains belonging to these C-types showed greater adhesion to A-498 cells than did clinical strains (17 ± 13 bacteria/cell versus 13 ± 11 bacteria/cell; p < 0.001), whereas clinical strains showed significantly greater adhesion to Calu-3 and Caco-2 cells than did environmental strains (p < 0.001 for both). The virulence genes and antibiotic resistance profiles of the strains were similar; however, the prevalence of environmental strains carrying both exoS and exoU was significantly (p < 0.0368) higher than clinical strains. While all strains were resistant to ticarcillin and ticarcillin-clavulanic acid, resistance against aztreonam, gentamicin, amikacin, piperacillin, and ceftazidime varied among environmental and clinical strains. These results suggest that environmental strains of P. aeruginosa carry virulence properties similar to clinical strains, including adhesion to various human cell lines, with some strains showing a higher adhesion to specific cell lines, indicating they may have a better ability to cause infection in those sites under predisposing conditions of the host.


Subject(s)
Pseudomonas aeruginosa/genetics , Anti-Bacterial Agents/pharmacology , Caco-2 Cells , Clavulanic Acids/pharmacology , Drug Resistance, Microbial/drug effects , Environmental Microbiology , Humans , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/pathogenicity , Random Amplified Polymorphic DNA Technique , Ticarcillin/pharmacology , Virulence/drug effects
3.
FEMS Microbiol Lett ; 363(4)2016 Feb.
Article in English | MEDLINE | ID: mdl-26825678

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.


Subject(s)
Penaeidae/microbiology , Photobacterium/isolation & purification , Vibrio/isolation & purification , Animals , Aquaculture , Australia , Bacterial Proteins/genetics , Bacterial Typing Techniques , Biofilms/growth & development , DNA-Binding Proteins/genetics , Flagella/genetics , Hemolysin Proteins/genetics , Host-Pathogen Interactions , Penaeidae/anatomy & histology , Photobacterium/classification , Photobacterium/genetics , Photobacterium/pathogenicity , RNA, Ribosomal, 16S/genetics , Transcription Factors/genetics , Vibrio/classification , Vibrio/genetics , Vibrio/pathogenicity , Virulence/genetics
4.
Microb Ecol ; 68(4): 679-87, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25027277

ABSTRACT

Vibrio and Pseudomonas species have been shown to be part of the normal microbiota of Atlantic salmon (Salmo salar L.), with some strains causing disease in fish. The factors affecting their prevalence and persistence in the salmon gut, however, have not been well studied. In this study, we collected 340 Vibrio and 150 Pseudomonas isolates from the hindgut of farmed Tasmanian Atlantic salmon, fed with two commercially available diets. Samples were collected every 6-8 weeks between July 2011 and May 2012. Isolates from selective agar were initially identified using biochemical tests and confirmed using genus-specific primers and 16S ribosomal RNA (16S rRNA) sequencing. Random amplified polymorphic DNA (RAPD) PCR was used to type both Pseudomonas and Vibrio; the latter was further typed using a biochemical fingerprinting method (PhP-RV plates). We observed low species diversity with strains comprising Vibrio ichthyoenteri/Vibrio scophthalmi, Vibrio crassostreae/Vibrio splendidus, Aliivibrio finisterrensis, Photobacterium phosphoreum and Pseudomonas fragi. Out of 340 Vibrio isolates, 238 (70 %) belonged to 21 clonal types and were found predominantly during summer when water temperatures reached 15 to 21 °C. Of these, the four major clonal types were found in multiple samples (70 %). P. fragi, on the other hand, was only found during the colder water temperatures and belonged to 18 clonal types. The presence of both groups of bacteria and their clonal types were independent of the fish diets used, suggesting that the water temperature was the main factor of the prevalence and persistence of these bacteria in the gut of Atlantic salmon.


Subject(s)
Fish Diseases/microbiology , Pseudomonas Infections/veterinary , Pseudomonas/isolation & purification , Salmo salar , Seasons , Vibrio Infections/veterinary , Vibrio/isolation & purification , Animals , Aquaculture , Fish Diseases/epidemiology , Molecular Sequence Data , Polymerase Chain Reaction/veterinary , Population Dynamics , Pseudomonas/classification , Pseudomonas Infections/epidemiology , Pseudomonas Infections/microbiology , RNA, Ribosomal, 16S/genetics , Random Amplified Polymorphic DNA Technique/veterinary , Sequence Analysis, DNA/veterinary , Tasmania/epidemiology , Vibrio/classification , Vibrio Infections/epidemiology , Vibrio Infections/microbiology
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