Lactococcus lactis subspecies lactis also causes white muscle disease in farmed giant freshwater prawns Macrobrachium rosenbergii

in Sciences Citation Index(SCI), 科學引文索引資料庫(SCI)
標題Lactococcus lactis subspecies lactis also causes white muscle disease in farmed giant freshwater prawns Macrobrachium rosenbergii
出版類型SCI(Sciences Citation Index)
出版年度2008
AuthorsShih-Chu Chen, 陳石柱
開始頁9
頁數8
出版日期2008 / 4
其他編號0000
中文摘要

From May to August 2001 in Taiwan, 27 farms for the giant freshwater prawn Macrobrachium
rosenbergii experienced white tail disease outbreaks in animals approximately 3 to 5 mo
old, with total lengths from 6 to 8 cm. Examination of the infected prawns revealed not only previously
reported Lactococcus garvieae (16 farms) but also the novel L. lactis subsp. lactis (10 farms).
One farm had shrimp infected with both bacteria. In the farms with L. lactis infections, the cumulative
mortality was approximately 25 to 60%. Gross signs of disease were opaque and whitish muscles,
while histopathology included marked edema and necrotic lesions, with inflammation in the muscles
and hepatopancreas. Bacteria isolated using brain/heart infusion medium or tryptic soy agar were
Gram-positive and ovoid. Eleven isolates from different farms were identified as L. lactis subsp. lactis
using API 20 Strep and Rapid ID32 Strep tests and using PCR assays specific for the L. lactis subsp.
lactis 16S rDNA gene (650 bp amplicon) and for the 16S to 23S rDNA interspacer region (380 bp
amplicon). In addition, sequencing of the full 16S rDNA genes of 2 of the isolates (MR17 and MR26;
GenBank Accession Numbers AF493058 and AF493057, respectively) revealed 99.9% identity
between the isolates and 98.7% identity to several complete 16S rRNA sequences of L. lactis subsp.
lactis at GenBank. Experimental infections with our isolates gave gross signs and histopathological
changes similar to those seen in naturally infected prawns. The mean lethal dose of 4 isolates and the
reference strain L. lactis subsp. lactis BCRC 10791 ranged from 4.2 × 106 to 2.5 × 107 colony-forming
units prawn–1, indicating virulence similar to that previously reported for L. garvieae. This is the first
report confirming L. lactis subsp. lactis as a pathogen in juvenile and adult prawns from aquaculture.

期刊名稱DISEASES OF AQUATIC ORGANISMS
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