Pathogenic Gram-positive cocci in South African rainbow trout, Oncorhynchus mykiss (Walbaum)

Bekker, Anneke; Hugo, Celia J.; Albertyn, Jacobus; Boucher, Charlotte E.; Bragg, R.R.

doi:10.1111/j.1365-2761.2011.01259.x

Cited by 16 publications

(14 citation statements)

References 17 publications

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“…In our study, 48 hr p.i with L. garvieae RTCLI04 (2.6 × 10 5 CFU ml −1 ), clinical signs of lactococcosis such as reduced intake of feed, lethargy, abnormal swimming and melanosis were apparent in majority of the rainbow trout juveniles. Haemorrhage in buccal area and periphery of the eye, anus inflammation and haemorrhage in pelvic fins were first visible at 72 hr p.i, which was similar to the clinical and macroscopic findings of other investigators (Austin & Austin, ; Bekker, Hugo, Albertyn, Boucher, & Bragg, ; Vendrell et al., ). However, rainbow trout immersed in L. garvieae did not show any clinical signs till 5th day and first mortality was recorded on 6th day.…”

Section: Discussionsupporting

confidence: 89%

First report on characterization and pathogenicity study of emergingLactococcus garvieaeinfection in farmed rainbow trout,Oncorhynchus mykiss(Walbaum), from India

Shahi

Mallik

Sahoo

et al. 2018

Transbound Emerg Dis

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"Warm water lactococcosis" in farm-reared rainbow trout, Oncorhynchus mykiss (Walbaum) in the northern Himalayan region of India, caused by bacterium Lactococcus garvieae is described in this study. Nine bacterial isolates were recovered from the organs of haemorrhagic septicaemia rainbow trout and were subjected to biochemical and molecular identification. Cell surface characteristics and virulence of the bacterial isolates are also described. All the nine bacterial isolates had homogenous biochemical characteristics and were Gram-positive, short chains forming (two to eight cells long), α-haemolytic, non-motile ovoid cocci. Partial 16S rDNA nucleotide sequence (~1,400 bp) of current isolates shared 99% identities with the 16S rDNA nucleotide sequence of L. garvieae R421, L. garvieae FMA395 and L. garvieae CAU:1730. The identity of the bacterial isolates was further confirmed by PCR amplification of L. garvieae-specific ~1,100 bp fragment. Transmission electron microscopy (TEM) of one representative isolate, L. garvieae RTCLI04, indicates that the isolated strain lacks thick outer capsule and is of KG+ (non-capsulates) phenotype. An intraperitoneal and intramuscular injection (2.6 × 10 CFU ml ) and also immersion in bacterial suspension @ of 2.6 × 10 CFU ml to healthy rainbow trout juveniles (body weight: 27.5 ± 3.7 g) with L. garvieae RTCLI04 caused 80%, 60% and 10% cumulative mortality in challenged fish, respectively, within 15 days post-infection. The haemorrhagic septicaemic disease was reproduced experimentally. Histopathological examination of organs of experimentally infected fish revealed extensive degenerative and inflammatory changes in eye, kidney, gill and liver. PCR amplification of several putative virulence genes such as haemolysins, adhesins, LPxTG-containing surface proteins and adhesins cluster confirms the virulence of our Indian L. garvieae isolates. To the best of our knowledge, we are reporting for the first time that L. garvieae is associated with fatal haemorrhagic septicaemia in farmed rainbow trout in India.

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Section: Discussionsupporting

confidence: 89%

First report on characterization and pathogenicity study of emergingLactococcus garvieaeinfection in farmed rainbow trout,Oncorhynchus mykiss(Walbaum), from India

Shahi

Mallik

Sahoo

et al. 2018

Transbound Emerg Dis

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“…The earliest symptoms of infection include anorexia, melanosis and erratic swimming. Other external signs include unior bilateral exophthalmia, swollen ab domen and anal prolapsus (Eldar & Ghittino 1999, Bekker et al 2011. At ne cropsy, accumulation of ascitic fluid in the peritoneal cavity, congestion of internal organs, enlargement of spleen and liver, and exudate covering the brain are observed (Bragg & Broere 1986, Eldar & Ghittino 1999.…”

Section: Lactococcosis In Aquaculture Symptoms and Clinical Signsmentioning

confidence: 99%

“…(Bragg & Broere 1986) were recently reclassified as Enterococcus spp. and L. garvieae based on 16S ribosomal RNA (rRNA) sequencing (Bekker et al 2011). Recent advances in next generation sequencing technologies have contributed to a steady increase in the numbers of publically available full and partial genome sequences of L. garvieae over the last decade, as described in Table 2.…”

Section: Lactococcus Garvieaementioning

confidence: 99%

Lactococcus garvieae: an emerging bacterial pathogen of fish

Meyburgh

Bragg²,

Boucher³

2017

Dis. Aquat. Org.

122

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Lactococcus garvieae is the causative agent of lactococcosis, a hyperacute, haemorrhagic septicaemia of fish. This bacterium is also considered an emerging zoonotic pathogen, as reports of human infection are increasing. Significant economic loss in aquaculture is suffered as a result of lactococcosis, as numerous freshwater and marine species of commercial interest are affected. Development of antibiotic resistance in L. garvieae to several chemotherapeutic agents complicates and restricts treatment options. Effective, sustainable treatment and prevention options are thus needed, but progress is impeded by the lack of knowledge concerning several aspects of the disease and the pathogen. This review aims to present the latest research on L. garvieae, with specific focus on pathogenesis, virulence factors, risks associated with chemotherapeutic administration and possible control options.

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“…The species L. garvieae has been isolated from several fish species worldwide, namely in Japan [27], South Africa [28], Europe [29], and Brazil. Its first outbreak was reported in 2009 [7].…”

Section: The Analysis Of the Common Bacterial Fish Pathogensmentioning

confidence: 99%

Identification of Bacterial Fish Pathogens in Brazil by Direct Colony PCR and 16S rRNA Gene Sequencing

Sebastião¹,

Furlan²,

Hashimoto³

et al. 2015

AiM

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Intensive fish farming systems in Brazil have increased the disease incidence, mainly of bacterial origin, due to higher stocking density, high organic matter levels and poor quality of the aquatic environment that causes high mortality rates during outbreaks. The identification of pathogenic species using a fast and reliable method of diagnosis is essential for successful epidemiological studies and disease control. The present study evaluated the use of direct colony PCR in combination with 16S rRNA gene sequencing to diagnose fish bacterial diseases, with the goal of reducing the costs and time necessary for bacterial identification. The method was successful for all 178 isolates tested and produced bands with the same intensity as the standard PCR performed using pure DNA. In conclusion, the genetics methods allowed detecting the most common and important pathogens in Aquaculture, including 12 species of occurrence in Brazilian fish farms. The results of the present study constitute an advance in the available diagnostic methods for bacterial pathogens in fish farms.

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Pathogenic Gram-positive cocci in South African rainbow trout, Oncorhynchus mykiss (Walbaum)

Cited by 16 publications

References 17 publications

First report on characterization and pathogenicity study of emergingLactococcus garvieaeinfection in farmed rainbow trout,Oncorhynchus mykiss(Walbaum), from India

First report on characterization and pathogenicity study of emergingLactococcus garvieaeinfection in farmed rainbow trout,Oncorhynchus mykiss(Walbaum), from India

Lactococcus garvieae: an emerging bacterial pathogen of fish

Identification of Bacterial Fish Pathogens in Brazil by Direct Colony PCR and 16S rRNA Gene Sequencing

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