Streptococcus parauberis During 1993 and 1994 low level 01 5 mortalities

Streptococcus parauberis during 1993 and 1994 low

This preview shows page 86 - 88 out of 594 pages.

Streptococcus parauberis During 1993 and 1994, low-level (0.1-5%) mortalities occurred in farmed turbot of 0.8 to 2 kg in size in northern Spain (Domenech et al., 1996). Isolates were obtained and identified by phenotypic (Rapid ID32 and API 50CH systems) and genotypic data (16S rRNA sequencing) as Str. parauberis; an organism known previously as Str. uteris genotype II. Eighteen isolates recovered from diseased turbot in northwest Spain (Galicia) were subjected to ribotyping and RAPD analyses with the data demonstrating marked homogeneity among the cultures (Romalde et al., 1999).
Image of page 86
Characteristics of the pathogens: Gram-positive bacteria 63 Streptococcus parauheris After overnight incubation, pure cultures produce whitish shghtly ot-haemolytic colonies of 1.5 to 2 mm in diameter. These contain non-motile, Gram-positive short rods/cocco-bacilli in pairs or short chains, which produce alkaline phospha- tase, a-galactosidase, P-glucuronidase and pyrrolidonyl arylamidase, but not cat- alase, indole or catalase, grow at 10 to 37°C but not at 4 or 45°C, in 4.5 but not 6.5% (w/v) sodium chloride or at pH 9.6 or on MacConkey agar, and degrade arginine and hippurate (some strains). There was a 100% sequence homology between the fish isolates and Str. parauberis. The only reliable difference between the turbot isolates and the type strain concerned the action on D-raffinose which was negative for the latter (Domenech et ai, 1996). AEROBIC, GRAM-POSITIVE RODS AND COCCI Aerobic, heterotrophic. Gram-positive rods and cocci have received great attention from fisheries microbiologists, largely because of the severity of the diseases caused by pathogenic representatives. There are nine genus groupings which will be considered in this chapter, namely Bacillus, Corynebacterium, Micrococcus, Mycobacterium, Nocardia, Planococcus, Rhodococcus, Renibacterium and Staphylococcus. Renibacterium salmoninarum Bacterial kidney disease (BKD, Dee disease, corynebacterial kidney disease, salmonid kidney disease) was described initially in 1930 for a condition in Atlantic salmon (Salmo salar) found in the Rivers Dee and Spey in Scotland (Mackie et ai, 1933; Smith, 1964). Histological examination of fixed material revealed the presence of large numbers of Gram-positive rods in lesions. At various times, the causal agent of BKD has been linked with Corynebacterium (Ordal and Earp, 1956; Smith, 1964, Sanders and Fryer, 1978; Austin and Rodgers, 1980), Brevibacterium (Smith, 1964), Listeria (Bullock et ai, 1975), Lactobacillus (Vladik et al, 1974) and Rickettsia (Snieszko and Griffin, 1955). Subsequently, it was appreciated that the organisms were sufficiently unique to warrant separate species status, so Corynebacterium salmoninus was described (Sanders and Fryer, 1978). With further information, these authors reahsed that the pathogen belonged in a new, as yet undescribed genus and, therefore, proposed Renibacterium. Thus, the causal agent of BKD became classified as Renibacterium salmoninarum (Sanders and Fryer, 1980).
Image of page 87
Image of page 88

You've reached the end of your free preview.

Want to read all 594 pages?

  • Spring '20
  • Bacteria, representative, gram-negative bacteria

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes
A+ icon
Ask Expert Tutors