Description of a New Species of Sulcospira (Gastropoda: Pachychilidae) From Guangxi, China Based on Morphology and Molecular Evidence.

A new species of pachychilid freshwater gastropod, Sulcospira elonga sp. nov., is described from Guangxi Zhuang Autonomous Region, China, based on morphological and molecular evidence. The new species is distinguished from its congeners by a combination of characters, including eight to 11 whorls, spiral lirae and axial ribs present, the shell width is about 1.4-1.6 times the maximum width except for the body whorl, and stomach with outer and inner crescentic pads connected to each other.

A new loach species of the genus Oreonectes (Teleostei, Cypriniformes, Nemacheilidae) from Guangxi, China.

A new loach species, Oreonectesandongensissp. nov. is described from the Guangxi Zhuang Autonomous Region, China. The new species can be differentiated from other members of the genus by combinations of characters: a developed posterior chamber of the swim bladder, 13-14 branched caudal-fin rays, 8-16 lateral-line pores, body width 12-15% of standard length (SL), interorbital width 42-47% of head length (HL), and caudal peduncle length 11-16% of SL. Bayesian inference phylogenetic analysis based on mitochondrial Cyt b provided strong support for validity of O.andongensissp. nov. (uncorrected p-distance 6.0-7.5%).

Troglonectes canlinensis sp. nov. (Teleostei: Nemacheilidae), a New Troglomorphic Loach from Guangxi, China.

A new species of the genus Troglonectes is described based on specimens from a karst cave in Andong Town, Xincheng County, Liuzhou City, Guangxi, China. Troglonectes canlinensis sp. nov. can be distinguished from its congener species by the following combination of characteristics: eye degenerated into a black spot; whole body covered by scales, except for the head, throat, and abdomen; incomplete lateral line; forked caudal fin; 8-10 gill rakers on the first gill arch; 13-14 branched caudal fin rays; 8-9 branched dorsal fin rays; 5-6 anal fin rays; 9-10 pectoral fin rays; upper adipose keel depth mostly 1/2 of the caudal peduncle depth; and caudal fin forked.

A new loach species of Troglonectes (Teleostei: Nemacheilidae) from Guangxi, China.

A new species of the genus Troglonectes is described from Guangxi Zhuang Autonomous Region, China. Troglonectes hechiensis sp. nov. can be easily distinguished from its congeners based on the following characters: eyes normal; whole body covered by scales except head, throat, and abdomen; lateral line incomplete; caudal fin concave; and color pattern present on body.

Genomic comparison of virulent and non-virulent serotype V ST1 Streptococcus agalactiae in fish.

Streptococcus agalactiae or Group B Streptococcus (GBS) is the major pathogen causing pneumonia and meningitis in human, mastitis in dairy cows, and streptococcal disease in tilapia. Previous studies have shown that fish GBS strains are correlated with human GBS strains in evolution and might have cross-host infection ability. Although the invasive disease caused by ST1 GBS in non-pregnant adults and cows is increasing worldwide, infection of fish by ST1 GBS has not been reported. The aim of this study was to determine whether ST1 GBS was virulent in fish and to investigate the genomic characteristics of ST1 GBS strains with different pathogenicity in tilapia. The human-derived serotype V ST1 GBS strains NNA048 and NNA038 were used to intraperitoneally challenge Nile tilapia (Oreochromis niloticus) with doses of 1.0×109CFU/fish, 1.0×107CFU/fish, and 1.0×105CFU/fish, respectively. The cumulative mortality rates of NNA048 infection at three different doses were 100.00%, 83.33%, and 40.00%. In contrast, there were no any sick or dead fish in NNA038 infection group. Histopathological results indicated that challenge of tilapia with NNA048 caused different degree of degeneration and necrosis in brain, liver, spleen, head kidney, and gut, and a large number of blue-stained Streptococcus granules were observed in the tissues. In contrast, there were no any lesions in the tissues of tilapia that were challenged with NNA038. Genome comparison showed that the major genome differences between NNA048 and NNA038 were attributed to the different phage sequences, and there was a 49.8kb length, intact phage sequence encoding 68 proteins in NNA048 genome. SNV and Indels analysis between NNA038 and NNA048 genomes indicated that there were a total of 96 SNVs, 5 deletions and 1 insert. Taken together, serotype V ST1 GBS was comprised of virulent and nonvirulent strains to tilapia, and gene rearrangement might be the main reason of causing different levels of virulence between strains.

Streptococcus agalactiae isolates of serotypes Ia, III and V from human and cow are able to infect tilapia.

Recent studies have shown that group B streptococcus (GBS) may be infectious across hosts. The purpose of this study is to investigate the pathogenicity of clinical GBS isolates with serotypes Ia, III and V from human and cow to tilapia and the evolutionary relationship among these GBS strains of different sources. A total of 27 clinical GBS isolates from human (n=10), cow (n=2) and tilapia (n=15) were analyzed using serotyping, multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Among them, 15 isolates were tested for their pathogenicity to tilapia. The results showed that five human GBS strains (2 serotype III, 2 serotype Ia and 1 serotype V) infected tilapia with mortality rate ranging from 56.67% to 100%, while the other five human GBS strains tested were unable to infect tilapia. In addition, two cow GBS strains C001 and C003 of serotype III infected tilapia. However, they had significantly lower pathogenicity than the five human strains. Furthermore, human GBS strains H005 and H008, which had very strong ability to infect tilapia, had the same PFGE pattern. MLST analysis showed that the five human and the two cow GBS strains that were able to infect tilapia belonged to clonal complexes CC19, CC23 and CC103. The study for the first time confirmed that human or cow GBS clonal complexes CC19, CC23 and CC103 containing strains with serotypes Ia, III and V could infect tilapia and induce clinical signs under experimental conditions.