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Controlling the growth of food-borne pathogens in foodstuffs is important to enhance food safety and promote higher food safety standards. A number of naturally occurring compounds (e.g., bacteriocins and plant-derived compounds) have been widely reported to be safe and effective antimicrobial agents against spoilage and food-borne pathogenic bacteria. The aim of the present work was to evaluate the antibacterial potential of a semi-purified preparation (SPP) containing bacteriocin from Bacillus velezensis BUU004, a mixture of lemongrass (Cymbopogon citratus (DC) Stapf.), chili spur pepper (Capsicum frutescens L.) extracts, and their combination to control the growth of Escherichia coli and Salmonella Typhimurium in dried, crushed, and seasoned squid during 28 d of storage. The mixed herb extracts (160 mg/mL) showed stronger inhibitory activity against E. coli and S. Typhimurium than the SPP (800 AU/mL) from B. velezensis BUU004. Interestingly, the combination of SPP from B. velezensis BUU004 and the mixed herb extracts substantially decreased the numbers of both pathogens in dried seasoned squid during storage as compared to that observed with the individual additives. The bactericidal activity of the SPP from B. velezensis BUU004 in combination with the mixed herb extracts against the food-borne pathogens involved cell lysis as ruptured cell walls were observed by a scanning electron microscopy. Therefore, the SPP from B. velezensis BUU004 combined with the mixed herb extracts offers tremendous advantages as a novel, safe, natural, and effective way to improve the biosafety of dried seafood products. [ABSTRACT FROM AUTHOR]

Several microorganisms, including Bacillus and yeasts species, are widely used as aquaculture probiotics. In the present study, a mixed Bacillus sp. contained five species of B. thuringiensis BUU 001, B. megaterium BUU 002, B. polymyxa BUU 003, B. licheniformis BUU 004, and B. subtilis BUU 005, and a mixed yeast probiotics contained Debaryomyces hansenii BUU 01 and Rhodotorula sp. BUU 02. The effects of mixed microbial probiotics as a dietary supplement on growth, survival, and microbiological changes of juvenile whiteleg shrimp (Litopenaeus vannamei) were investigated. Shrimp (~5.7–5.8 g) were fed a commercial diet alone (control) or with one of three probiotic supplements—freeze-dried mixture of Bacillus (FB), freeze-dried mixture of Bacillus and yeast (FBY), and freeze-dried mixture of yeast (FY)—for 90 days in simulated earthen ponds. Growth of FB-fed shrimp was significantly higher (P < 0.05) than those fed with FBY, FY, and control diets. However, survival was not significantly different (P > 0.05) among the three treated groups but was significantly higher (P < 0.05) than that of the control. Numbers of culturable heterotrophic bacteria in intestine were not significantly different (P > 0.05) among the four groups. Bacillus numbers in FB- and FBY-fed shrimp increased significantly (P < 0.05) in intestine. Yeast numbers in intestine of FBY- and FY-treated shrimp were significantly higher (P < 0.05) than those of FB-treated and control shrimp and increased significantly (P < 0.05) during the rearing period, while no yeast was observed in FB-treated and control shrimp. Numbers of Vibrio in intestine were significantly lower (P < 0.05) in the three treated groups than the control. Administration of mixed Bacillus, mixed yeasts, or Bacillus mixture in combination with mixed yeasts resulted in improved (P < 0.05) growth and survival and reduced Vibrio numbers along with an increase in beneficial probiotic abundance and a decrease in the number of potential pathogenic bacteria (V. parahaemolyticus and V. cholerae) in digestive tract of juvenile L. vannamei. [ABSTRACT FROM AUTHOR]

Development of a novel biopreservative harmless to human health has gained increasing attention to control spoilage and pathogenic bacteria in food products. The aims of the present work were to characterise partially purified substance from Bacillus velezensis BUU004 (PBV), evaluate its cytotoxicity, and assess the presence of encoding genes associated with enterotoxin production in B. velezensis BUU004. The highest antibacterial activity was achieved at 18 h post-incubation in stationary growth phase. The PBV containing bacteriocin displayed proteinaceous nature because its activity was partially inactivated by chymotrypsin and papain, and fully degraded by pepsin, proteinase K and trypsin. Bacteriocin in PBV was thermoresistant up to 96°C, and pH stable ranging from 3.0 - 9.0. It also showed a broad spectrum of antibacterial activity against B. cereus, B. coagulans, Listeria monocytogenes, Micrococcus luteus, Staphylococcus aureus, Escherichia coli, E. coli O157:H7, and Salmonella Typhimurium. The molecular weight of the bacteriocin was approximately 5.75 kDa, and the amino acid sequence revealed 43% similarity with existing antimicrobial peptides as determined by an LC-MS/MS analysis. Furthermore, B. velezensis BUU004 produced the bacteriocin that has a low IC50 of 927.4 µg/mL to HK-2 cells along with absence of enterotoxin genes: cytotoxin K (cytK), hemolysin (hlyII), hemolytic enterotoxin HBL (hblABCD), nonhemolytic enterotoxin NHE (nheABC) and cereulide (cesABCD), indicating its basic biosafety characteristic. Our results suggest that a bacteriocin produced by B. velezensis BUU004 has promising potential as a safe biopreservative in the food industry. [ABSTRACT FROM AUTHOR]

Background: Myelin oligodendrocyte glycoprotein encephalomyelitis (MOG-EM) includes patients with (i) monophasic or relapsing acute optic neuritis, myelitis, brainstem encephalitis, or encephalitis; (ii) magnetic resonance imaging (MRI) or electrophysiological evidence of central nervous system (CNS) demyelination; and (iii) MOG-immunoglobulin G (IgG) seropositivity. Clinical Description: A 4-year-old girl presented with fever and excruciating headache for 10 days. Her vitals were stable and systemic examination was normal. Cerebrospinal fluid (CSF) analysis revealed 10 lymphocytes and normal biochemistry. After 5 days, she developed a fever and a seizure. Repeat CSF showed increased cells (60% lymphocytes), normal protein, and sugar. MRI brain was normal. She was managed symptomatically. CSF meningoencephalitis panel was negative. The child improved and was discharged. After 2 weeks, the headache recurred with associated blurring of vision. Bilateral papillitis, MRI brain abnormalities suggestive of acute disseminated encephalomyelitis (EM), and bilateral prolonged latency on visual evoked potential (VEP) were found. Anti-MOG antibodies were positive. The final diagnosis was MOG-EM. Management: The child was started on methylprednisolone therapy as per standard protocol. The vision improved and headache disappeared. She is on regular follow-up and is asymptomatic. Conclusion: MOG-IgG testing should be done in patients with (i) monophasic or relapsing acute optic neuritis, myelitis, brainstem encephalitis, or encephalitis; (ii) radiological or VEP findings compatible with CNS demyelination; and (iii) at least 1 of 25 delineated findings on MRI, fundoscopy, CSF, histopathology, clinical phenotype, or treatment response.

This study was conducted to investigate the efficacy of dry shipper for the cryostorage of silver barb (Barbodes gonionotus) sperm, the subsequent risk of bacterial cross-contamination, and the effects of Aeromonas hydrophila on post-thaw sperm. Semen was diluted with calcium-free Hank's balanced salt solution containing 10% ME 2 SO, frozen at -8 °C/min and stored for 14 d in a dry shipper. A significant decline (P < 0.05) in the post-thaw sperm motility and viability of samples kept in the dry shipper for 14 d showed a reverse correlation (P < 0.05) with a slight increase in temperature within the dry shipper. The levels of contaminated bacteria in the compartments of the dry shipper were significantly (P < 0.05) lower than those detected in the liquid nitrogen tank. Bacteria from the atmosphere could recontaminate the chambers of the dry shipper and liquid nitrogen tank after 14 d. Bacillus was the most common bacteria isolated from the dry shipper, liquid nitrogen tank, circulating air, bench surface and outer surface of straws. There was no cross-contamination of A. hydrophila from contaminated straws to pathogen-free straws kept in either cryogenic tank. Post-thaw sperm motility and sperm viability significantly (P < 0.05) declined during cryostorage in the dry shipper and liquid nitrogen tank due to the introduction of A. hydrophila and the interaction effect of A. hydrophila and freezing. This study reports, for the first time, the efficacy of a dry shipper for the cryostorage of fish sperm for at least 14 d without a risk of bacterial cross-contamination., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purposive use of cryopreserved sperm contaminated with pathogenic agents has increased the risk of spreading of fish diseases. The objective of this study was to investigate the effects of A. hydrophila subsp. hydrophila and P. fluorescens inoculations into cryostored milt on fertilization capacity and transmission potential to embryos of silver barb (Barbodes gonionotus) with or without 0.25% penicillin-streptomycin (PS) administration. The experiment comprised six treatments: addition of milt into T1) extender only, T2) extender with 0.25% PS, T3) extender with A. hydrophila subsp. hydrophila (BG19), T4) extender with A. hydrophila subsp. hydrophila (BG19) and 0.25% PS, T5) extender with P. fluorescens (BG20) and T6) extender with P. fluorescens (BG20) and 0.25% PS. Milt were loaded into 0.25-mL straws and cryostored in the controlled-rate programmable freezer. After a cryostorage for 28 d, post-thawed sperm were evaluated for the fertilization capacity and risk of pathogen transmission to embryos. Inoculation of A. hydrophila subsp. hydrophila and P. fluorescens into extended milt (T3 and T5) caused a reduction (P < 0.05) in fertilization capacity of cryopreserved sperm. Cryopreserved sperm inoculated with the two pathogenic bacteria and 0.25% PS (T4 and T6) did not fertilize the eggs. The two pathogenic bacteria could be transmitted into embryos after artificial insemination of eggs with bacterial-inoculated cryopreserved sperm, suggesting that the risks of disease transmission via cryopreserved fish sperm would exist. This is the first study reporting pathogenic bacterial transmission on in vitro fish embryos through artificial insemination of cryopreserved sperm., (Copyright © 2017. Published by Elsevier Inc.)

This objective of the study was to evaluate the effects of A. hydrophila subsp. hydrophila and P. fluorescens on sperm motility, sperm viability and sperm morphometry of cryopreserved silver barb (Barbodes gonionotus) semen and survival of tested bacteria after cryostorage. Semen was diluted in a calcium-free Hank's balanced salt solution (Ca-F HBSS) supplemented with or without 0.25% penicillin-streptomycin (PS) after which A. hydrophila subsp. hydrophila or P. fluorescens was immediately added into extended semen prior to freezing. Extended semen and cryostored semen kept for 20 min, 24 h, 7 d, 14 d and 28 d were assessed for sperm motility, sperm viability, sperm morphometry, survival of challenged bacteria and the relationship between bacteria and sperm. Bacterial-exposed semen with or without 0.25% PS supplementation showed a significant reduction (P < 0.05) in sperm motility and viability during a cryostorage of 28 d, compared to semen without bacterial supplementation (control groups). Addition of A. hydrophila subsp. hydrophila and P. fluorescens resulted in a significant (P < 0.05) alteration of sperm morphometry of cryopreserved semen, especially flagellum width. The two pathogens were detected at a level of 10(5) CFU ml(-1) in cryostored semen with or without antibiotic supplementation. There were significant correlations among bacterial number, percentage of sperm motility and viability and flagellum width. In conclusion, the presence of A. hydrophila subsp. hydrophila and P. fluorescens had a deleterious effect on cryopreserved silver barb sperm based on a reduction in sperm motility and viability and alteration of sperm morphometry, especially flagellum width., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Disease prevention is a key aspect in developing cryopreservation procedures for fish sperm and in improving the reproductive biotechnology for commercially important aquatic species. The purpose of this study was to evaluate the effects of an antibiotic supplementation (0.25% penicillin-streptomycin, PS and 0.25% penicillin-gentamicin, PG) on sperm motility and viability, bacterial profile and fertilization capacity of cryopreserved silver barb (Barbodes gonionotus) semen. The experimental protocol involved three treatments: addition of PS alone; addition of PG alone; and no addition of antibiotics (Control). Semen samples were frozen and cryostored for 12-mo. Administration of 0.25% PS significantly (P<0.05) improved sperm motility and viability and reduced (P<0.05) total heterotrophic bacteria, Gram negative bacteria and pseudomonads bacteria in cryopreserved semen. Post-thawed semen treated with 0.25% PS did not contain contaminating bacteria including Bacillus subtilis subsp. inaquosorum, Bacillus safensis, Aeromonas punctata subsp. caviae, Serratia plymuthica, Pseudomonas azotoformans and Pseudomonas sp. Post-thawed semen supplemented with 0.25% PG showed degenerative changes in motility and viability of sperm. Eggs fertilized with 0.25% PS or antibiotic-free cryopreserved semen had similar fertilization rates, lower (P<0.05) than those of fresh semen. Incorporation of 0.25% PS was suitable for cryopreservation of silver barb semen based on the presence of good quality of post-thawed sperm and elimination of bacterial contaminants: B. subtilis subsp. inaquosorum, B. safensis, A. punctata subsp. caviae, Ser. plymuthica, P. azotoformans and Pseudomonas sp. This is the first study to investigate the antibiotic effect on the number of bacteria and their profile in cryopreserved semen of fish., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Biosafety issue associated with the risk of pathogenic contamination of cryopreserved semen is a common concern because of associated declines in sperm quality, storage period and disease transmission. This study was conducted to evaluate the effects of methods of semen collection on sperm quality and bacterial composition of post-thawed semen of silver barb (Barbodes gonionotus). Semen collection methods consisted of four treatments: (1) hand-stripping of abdomen without rinsing of urogenital area with water, (2) hand-stripping of abdomen after rinsing of urogenital area with water, (3) catheterization without rinsing of urogenital area with water and (4) catheterization after rinsing of urogenital area with water. Semen diluted with calcium-free Hank's balanced salt solution containing 10% dimethylsulfoxide (DMSO) was frozen at a freezing rate of -8°Cmin(-1) before plunging in liquid nitrogen. Post-thawed semen collected by catheterization after rinsing urogenital area had the lowest bacterial number, about 2-log reduction of total heterotrophic, Gram negative and pseudomonad bacteria, compared with the other three collection treatments. However, percentages of motile and viable sperm were not significantly (P>0.05) different among treatments. This method eliminated Flavobacterium aquatile, Bacillus megaterium, Kocuria varians, Staphylococcus haemolyticus and Aeromonas media in cryopreserved semen. This is the first report demonstrating the effects of semen collection methods on bacteriological quality of frozen-thawed fish semen., (Copyright © 2016 Elsevier B.V. All rights reserved.)