Invasive Infections Due to a Fish Pathogen,<i>Streptococcus iniae</i>

Weinstein, Mitchell R.; Litt, Margaret; Kertesz, Daniel A.; P, Wyper; Rose, David P.; Coulter, Mark; McGeer, Allison; Facklam, Richard R.; Ostach, Carola; Willey, Barbara M.; Borczyk, Al; Low, Donald E.

doi:10.1056/nejm199708283370902

Cited by 300 publications

(241 citation statements)

References 27 publications

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“…Syn- thetic, amidated wb-moronecidin also demonstrated activity against pathogenic isolates of S. iniae, which is an important pathogen for farmed hybrid striped bass, tilapia, and other aquaculture species (23). The MIC of moronecidin against S. iniae (1.25-2.5 M) is similar to the MICs of ␤-lactam antibiotics against this organism (40). In our in vitro experiments, we did not demonstrate resistance of this organism to moronedicin.…”

Section: Discussionsupporting

confidence: 56%

Discovery and Characterization of Two Isoforms of Moronecidin, a Novel Antimicrobial Peptide from Hybrid Striped Bass

Lauth¹,

Shike²,

Burns³

et al. 2002

Journal of Biological Chemistry

255

236

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We isolated a novel 22-residue, C-terminally amidated antimicrobial peptide, moronecidin, from the skin and gill of hybrid striped bass. Two isoforms, differing by only one amino acid, are derived from each parental species, white bass (Morone chrysops) and striped bass (Morone saxatilis). Molecular masses (2543 and 2571 Da), amino acid sequences (FFHHIFRGIVHVGKTIH(K/R) LVTGT), cDNA, and genomic DNA sequences were determined for each isoform. A predicted 79-residue moronecidin prepropeptide consists of three domains: a signal peptide (22 amino acids), a mature peptide (22 amino acids), and a C-terminal prodomain (35 amino acids). The synthetic, amidated white bass moronecidin exhibited broad spectrum antimicrobial activity that was retained at high salt concentration. An ␣-helical structure was confirmed by circular dichroism spectroscopy. The moronecidin gene consists of three introns and four exons. Peptide sequence and gene organization were similar to pleurocidin, an antimicrobial peptide from winter flounder. A TATA box and several consensus-binding motifs for transcription factors were found in the region 5 to the transcriptional start site. Moronecidin gene expression was detected in gill, skin, intestine, spleen, anterior kidney, and blood cells by kinetic reverse transcription (RT)-PCR. Thus, moronecidin is a new ␣-helical, broad spectrum antimicrobial peptide isolated from the skin and gills of hybrid striped bass.

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Section: Discussionsupporting

confidence: 56%

Discovery and Characterization of Two Isoforms of Moronecidin, a Novel Antimicrobial Peptide from Hybrid Striped Bass

Lauth¹,

Shike²,

Burns³

et al. 2002

Journal of Biological Chemistry

255

236

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Section: Introductionmentioning

confidence: 99%

“…In addition, S. iniae has established itself as a zoonotic risk, especially in areas of the world that preferentially prepare and consume raw fish (Lau et al, 2003). To date, at least 25 human cases of invasive streptococcal infection attributed to S. iniae have been confirmed in the USA, Canada, China and Taiwan, many of which were in immunocompromised patients (Agnew & Barnes, 2007;Sun et al, 2007;Weinstein et al, 1997); since there is currently no prospective epidemiological surveillance for human S. iniae infections, the true number may be much higher (Facklam et al, 2005;Lau et al, 2006).In spite of the economic and human health risks that S. iniae presents, a fully assembled genome sequence for this emerging pathogen is not yet available, and very little is known about its disease mechanisms. To better understand the molecular genetic basis of virulence in this versatile pathogen, we created a library of randomly generated transposon mutants that we screened for virulence Abbreviations: AMP, antimicrobial peptide; HSB, hybrid striped bass, i.p., intraperitoneal; PIA, polysaccharide intercellular adhesin, WT, wild-type.…”

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confidence: 99%

The novel polysaccharide deacetylase homologue Pdi contributes to virulence of the aquatic pathogen Streptococcus iniae

et al. 2010

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The aquatic zoonotic pathogen Streptococcus iniae represents a threat to the worldwide aquaculture industry and poses a risk to humans who handle raw fish. Because little is known about the mechanisms of S. iniae pathogenesis or virulence factors, we established a highthroughput system combining whole-genome pyrosequencing and transposon mutagenesis that allowed us to identify virulence proteins, including Pdi, the polysaccharide deacetylase of S. iniae, that we describe here. Using bioinformatics tools, we identified a highly conserved signature motif in Pdi that is also conserved in the peptidoglycan deacetylase PgdA protein family. A Dpdi mutant was attenuated for virulence in the hybrid striped bass model and for survival in whole fish blood. Moreover, Pdi was found to promote bacterial resistance to lysozyme killing and the ability to adhere to and invade epithelial cells. On the other hand, there was no difference in the autolytic potential, resistance to oxidative killing or resistance to cationic antimicrobial peptides between S. iniae wild-type and Dpdi. In conclusion, we have demonstrated that pdi is involved in S. iniae adherence and invasion, lysozyme resistance and survival in fish blood, and have shown that pdi plays a role in the pathogenesis of S. iniae. Identification of Pdi and other S. iniae virulence proteins is a necessary initial step towards the development of appropriate preventive and therapeutic measures against diseases and economic losses caused by this pathogen. INTRODUCTIONIn the past few decades, the pathogen Streptococcus iniae has emerged as a major hindrance to aquaculture operations worldwide (Agnew & Barnes, 2007), causing economic losses measured in hundreds of millions of dollars annually. In addition, S. iniae has established itself as a zoonotic risk, especially in areas of the world that preferentially prepare and consume raw fish (Lau et al., 2003). To date, at least 25 human cases of invasive streptococcal infection attributed to S. iniae have been confirmed in the USA, Canada, China and Taiwan, many of which were in immunocompromised patients (Agnew & Barnes, 2007;Sun et al., 2007;Weinstein et al., 1997); since there is currently no prospective epidemiological surveillance for human S. iniae infections, the true number may be much higher (Facklam et al., 2005;Lau et al., 2006).In spite of the economic and human health risks that S. iniae presents, a fully assembled genome sequence for this emerging pathogen is not yet available, and very little is known about its disease mechanisms. To better understand the molecular genetic basis of virulence in this versatile pathogen, we created a library of randomly generated transposon mutants that we screened for virulence Abbreviations: AMP, antimicrobial peptide; HSB, hybrid striped bass, i.p., intraperitoneal; PIA, polysaccharide intercellular adhesin, WT, wild-type.3These authors contributed equally to this work.The GenBank/EMBL/DDBJ accession number for the pdi sequence of Streptococcus iniae is FJ664396.Four supplementary f...

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“…S. iniae infection of rainbow trout (Oncorhynchus mykiss) produces a disease which substantially affects the brain, with only minor pathological changes in other organs (4). Recently, S. iniae has been isolated from diseased humans suffering from cellulitis, meningitis, and bacteremias, indicating a threat to public health (16).…”

mentioning

confidence: 99%

Recovery of Streptococcus iniae from Diseased Fish Previously Vaccinated with a Streptococcus Vaccine

Bachrach

Zlotkin²,

Hurvitz

et al. 2001

Appl Environ Microbiol

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Streptococcus iniae was recovered from diseased rainbow trout (Oncorhynchus mykiss, Walbaum) previously vaccinated against streptococcosis. PCR and serological methods indicate the presence of a new serotype in the diseased fish.The fish pathogen Streptococcus iniae (11) is endemic in various parts of the world, including Israel (6) and North America (10). S. iniae infection of rainbow trout (Oncorhynchus mykiss) produces a disease which substantially affects the brain, with only minor pathological changes in other organs (4). Recently, S. iniae has been isolated from diseased humans suffering from cellulitis, meningitis, and bacteremias, indicating a threat to public health (16).A specific S. iniae vaccine became available in 1995. From 1995 to 1997, all Israeli trout farms in the Upper Galilee, (which share water reservoirs) routinely vaccinated their entire stocks (roughly 3 million fish/year), reducing S. iniae-related mortalities from 50% annually to less than 5% (5). However, massive new outbreaks of the disease were recorded in 1997. Unlike the previous pathological manifestations, diseased fish exhibited multisystem organ involvement and diffuse internal hemorrhages. Brains samples were collected from diseased fish and streaked on Columbia agar base (Difco) supplemented with 5% (vol/vol) defibrinated sheep blood. Beta-hemolytic gram-positive cocci were detected following an incubation of 24 to 48 h at 24°C. Conventional identification schemes (API 20 STREP; BioMerieux SA, Marcy l'Etoie, France) suggested that all isolates (of 100 collected over 24 months) were S. iniae. The new isolates, unlike the previous isolates, were shown to be arginine dehydrolase (ADH) negative. Definitive identification was accomplished by PCR, using S. iniae 16S rDNAspecific primers (Zlotkin et al. [17]), which revealed the 300-bp S. iniae-specific PCR product in all isolates.Six (11)). The rDNA sequence analyses confirmed that the six isolates were S. iniae. All had an identical sequence (GenBank accession no. AF335573) and differed from that of S. iniae ATCC 29178 (GenBank accession no. AF335572) in six bases (99.6% homology). EcoRI and HindIII digests of DNAs extracted from early and recent isolates resulted in identical restriction fragment length polymorphism ribotype patterns (data not shown), indicating that all isolates cluster in the Israeli S. iniae rank (6). The use of additional endonucleases (PvuII or KpnI) did not provide strain-to-strain differentiation (data not shown).The random amplified polymorphic DNA (RAPD) technique ( Fig. 1) was used to distinguish early from recent isolates. Primer p14 (5ЈGATCAAGTCC), previously proven useful for discrimination among group A streptococcol strains, was used (Neeman et al. [8]). All early (1991 to 1995) isolates produced a band with an estimated length of 750 bp. No such band was found in the PCR product of the recent isolates (Fig. 1).Hyperimmune sera for serological differentiation were obtained by three monthly immunizations of rainbow trout with formalin-fixed S. inia...

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Invasive Infections Due to a Fish Pathogen,Streptococcus iniae

Cited by 300 publications

References 27 publications

Discovery and Characterization of Two Isoforms of Moronecidin, a Novel Antimicrobial Peptide from Hybrid Striped Bass

Discovery and Characterization of Two Isoforms of Moronecidin, a Novel Antimicrobial Peptide from Hybrid Striped Bass

The novel polysaccharide deacetylase homologue Pdi contributes to virulence of the aquatic pathogen Streptococcus iniae

Recovery of Streptococcus iniae from Diseased Fish Previously Vaccinated with a Streptococcus Vaccine

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