Edwardsiellosis in Wild Striped Bass From the Chesapeake Bay

Pure cultures of Edwarsiella tarda were isolated from body ulcers and internal organs of wild European eels caught in a Mediterranean freshwater coastal lagoon (Albufera Lake, Valencia, Spain) over a 1 yr period. Overall, the E. tarda isolation rate from wild eels was 9%, but this increased to 22.8% in diseased individuals. All 22 E. tarda isolates belonged to the 'wild-type' biogroup of the species and were virulent for eels (lethal dose that kills 50% of exposed individuals [LD 50 dose]: 10 4.85 to 10 6.83 CFU ind.-1 ), and therefore represented the aetiological agent of the haemorrhagic disease observed in wild European eels. The E. tarda isolates and E. tarda CECT 894T type strain were biochemically and serologically related and resistant to macrolides, antifolates, and glycopeptides, but only the isolates from wild eels were resistant to clindamicyn. This study is the first description of edwardsiellosis in a wild European eel population, and alerts us to the presence of E. tarda in natural wetland environments in Mediterranean Europe. KEY WORDS: Edwardsiella tarda · Wild European eels · Fish pathogen Resale or republication not permitted without written consent of the publisherDis Aquat Org 73: [77][78][79][80][81] 2006 type' strains associated with humans and fish infections; (2) , and H 2 S -Biogroup 2 strains, which have only been isolated from humans.The present study is the first to describe the occurrence of Edwardsiella tarda 'wild-type' strains in wild European eels. Infected eels were caught in a Mediterranean freshwater coastal lagoon (Albufera Lake, Valencia, Spain). We tested our isolates for their virulence for eels and for their microbial susceptibilities. In addition, their serological relationships were studied and compared with the E. tarda type strain. MATERIALS AND METHODS Sample collection and microbiological analysis.Over the period of 1 yr (October 2003 to December 2004, the wild European eel Anguilla anguilla collected from Albufera Lake (Valencia, Spain) was studied on 10 occasions. Samples were mainly collected in autumn and winter, because eel (silver and yellow states) capture rates were highest during these seasons. Albufera Lake is a freshwater lagoon located 12 km south of Valencia city, close to the Mediterranean Sea, from which it is separated by a small littoral bar approximately 1 km wide. The lake is used for fishing and recreation; furthermore, lake water is used for agricultural purposes (rice cultivation). Eels are caught in the lagoon using traditional fishing procedures and are then briefly stocked in concrete ponds (160 × 80 cm) supplied with well freshwater (22 to 24°C) until sold. Edwardsiella tarda was not isolated from the well freshwater that supplied holding tanks, and the containers had only been used to hold European eels (data not shown).A total of 88 eels were randomly chosen and analysed, including healthy eels as well as individuals showing pathological signs such as haemorrhagic fins, petechiae on the belly, and skin damage. Samples of s...

Section: Discussionsupporting

confidence: 75%

“…Edwardsiella tarda is the causative agent of edwardsiellosis, a common epizootic disease of cultured (Meyer & Bullock 1973, Wakabayashi & Egusa 1973, Kusuda & Kawai 1998 and wild fish species (FrancisFloyd et al 1993, Baya et al 1997. It has been reported in tropical and subtropical areas of Africa, America, Asia and Australia.…”

Section: Introductionmentioning

confidence: 99%

Occurrence of Edwardsiella tarda in wild European eels Anguilla anguilla from Mediterranean Spain

Alcaide¹,

Herraiz²,

Esteve³

2006

“…They also identified 2 distinct groups of E. tarda, termed EdwGI and EdwGII. The group EdwGI contained isolates EIB202 isolated from diseased turbot Scophthalmus maximus in Shandong, China (Wang et al 2009), isolate 080813 from a Japanese eel Anguilla japonica in Fugian, China (Wang et al 2011), and isolate FL6-60 isolated from a striped bass Morone saxatilis in Maryland, USA (Baya et al 1997). Comparatively, EdwGII contained the type strains from humans (ATCC #15947 and ATCC #23685) as well as isolate DT from oscar Astronotus ocellatus in Guangzhou, China (Castro et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Edwardsiella piscicida identified in the southeastern USA by gyrB sequence, species-specific and repetitive sequence-mediated PCR

Griffin¹,

Ware²,

Quiniou³

et al. 2014

125

A new Edwardsiella taxon was recently described from fishes of Europe and Asia. Phenotypically similar to E. tarda, extensive genetic and phenotypic characterization determined this new strain does not belong to any established Edwardsiella taxa, leading to the adoption of a new taxon, E. piscicida. Concurrent research in the USA also identified 2 genetically distinct taxa within the group of organisms traditionally classified as E. tarda. Comparisons of gyrB sequences between US isolates and E. piscicida from Europe and Asia identified several US isolates with > 99.6% similarity to the gyrB sequence of the E. piscicida type strain (ET883) but < 87% similarity to the E. tarda type strain (ATCC #15947). A discriminatory PCR was developed for the identification of E. tarda and 2 genetic variants of E. piscicida (E. piscicida and E. piscicida-like species). Using these PCR assays, a survey was conducted of 44 archived bacterial specimens from disease case submissions to the Aquatic Research and Diagnostic Laboratory (Stoneville, MS, USA) between 2007 and 2012. All 44 isolates, originally identified phenotypically and biochemically as E. tarda, were identified as E. piscicida by PCR. Repetitive sequence-mediated PCR (rep-PCR) analysis of these archived specimens suggests they are largely homogenous, similar to what has been observed for E. ictaluri. The gyrB sequence data, coupled with the E. piscicida specific-PCR and rep-PCR data, confirms that E. piscicida has been isolated from fish disease cases in the southeastern USA. Moreover, our survey data suggests E. piscicida may be more prevalent in catfish aquaculture than E. tarda.

“…Bacterial diseases in striped bass exhibiting skin lesions and scale loss have been attributed to a variety of aetiologies, including Aeromonas, Edwardsiella, Flexibacter, Pseudomonas, and Vibrio spp. (Toranzo et al 1983, Mitchell 1984, Sindermann 1988, Plumb 1991, Baya et al 1997. However, in the current epizootic the presence of nonbranching acid-fast bacteria within granulomas implicated mycobacteria as the causative agent and represented the first time that fish mycobacteriosis had been reported in the Chesapeake Bay or along the Atlantic Coast of the United States.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 98%

Isolation and characterization of mycobacteria from striped bass Morone saxatilis from the Chesapeake Bay

Rhodes

Kator²,

Kaattari³

et al. 2004

Mycobacteriosis in striped bass Morone saxatilis of Chesapeake Bay, USA, was first diagnosed in 1997 based on the presence of granulomatous inflammation and acid-fast bacteria in skin and spleen. To confirm histopathology, bacteriological detection and identification of mycobacteria were begun using splenic tissue from fish with and without skin ulcerations. On the basis of initial studies using a variety of selective and nonselective media, decontamination, homogenization and incubation conditions, a simple and quantitative recovery method using aseptic necropsy of splenic tissue was developed. Optimal recovery was obtained by spread-plating homogenates on Middlebrook 7H10 agar with incubation for 3 mo at 23°C. Mycobacteria were recovered from 76% (n = 149/196) of fish examined. Mycobacterial densities exceeded 10 4 colony forming units · g tissue -1in 38% of samples (n = 63/168) that were examined using a quantitative approach. The most frequently recovered mycobacterium, present in 57% (n = 109/192) of characterized samples, was the recently named new species Mycobacterium shottsii. Polyinfections of M. shottsii and other mycobacteria were observed in 25% of samples (n = 47/192) with densities of M. shottsii usually 1 or more orders of magnitude higher than co-isolate(s). Other mycobacteria recovered included isolates that, based on phenotypic traits, resembled M. interjectum, M. marinum, M. scrofulaceum, M. szulgai and M. triplex. M. marinum, commonly associated with fish mycobacteriosis and human disease, was recovered infrequently (3%, n = 6/192). The presence of multiple mycobacterial types occurring at high densities suggests that a variety of mycobacteria could be causative agents of mycobacteriosis in striped bass from the Chesapeake Bay. Striped bass is the major recreational fish species in the Chesapeake Bay, and the significance of the current epizootic to human health and the potential adverse effects on fish stocks are not known. KEY WORDS: Mycobacteriosis · Fish disease · Striped bass · Morone saxatilis · Mycobacterium marinum · Mycobacterium shottsii Resale or republication not permitted without written consent of the publisherDis Aquat Org 61: [41][42][43][44][45][46][47][48][49][50][51] 2004 ded during the early to mid-1990s but by the late 1990s concern for the health of these fish returned. An epizootic in Chesapeake Bay striped bass, characterized by skin lesions and granulomatous inflammation with associated acid-fast bacteria, was first described in 1997 (Baya 1998, Vogelbein et al. 1998. Bacterial diseases in striped bass exhibiting skin lesions and scale loss have been attributed to a variety of aetiologies, including Aeromonas, Edwardsiella, Flexibacter, Pseudomonas, and Vibrio spp. (Toranzo et al. 1983, Mitchell 1984, Sindermann 1988, Plumb 1991, Baya et al. 1997. However, in the current epizootic the presence of nonbranching acid-fast bacteria within granulomas implicated mycobacteria as the causative agent and represented the first time that fish mycobacteriosis had ...