A gelatinized lipopeptide diet effectively modulates immune response, disease resistance and gut microbiome in Penaeus vannamei challenged with Vibrio parahaemolyticus.

Penaeus vannamei is one of the most economically vital shrimp globally, but infectious diseases have hampered its proper production and supply. As antibiotics pose a huge threat to the environment and humankind, it is essential to seek an alternative strategy to overcome infection and ensure proper culture and production. The present study investigates the effect of an anti-infective biosurfactant derivative lipopeptide MSA31 produced by a marine bacterium on the growth performance, disease resistance, and the gut microbiome of P. vannamei when challenged with pathogenic Vibrio parahaemolyticus SF14. The shrimp were fed with a commercial and lipopeptide formulated diet for 60 days and the growth performance was analyzed. The lipopeptide fed shrimp group showed enhanced growth performance and specific growth rate with improved weight gain than the control group. The challenge experiment showed that the survival rate was significant in the lipopeptide fed group compared to the control group. The results revealed 100% mortality in the control group at the end of 12 h of challenge, while 50% of the lipopeptide diet-fed group survived 24 h, which indicates the enhanced disease resistance in shrimp fed with a lipopeptide diet. The test group also showed higher levels of digestive and immune enzymes, which suggests that the lipopeptide diet could positively modulate the digestive and immune activity of the shrimp. The gut microbiome profiling by Illumina high-throughput sequencing revealed that the most abundant genera in the lipopeptide diet-fed group were Adhaeribacter, Acidothermus, Brevibacillus, Candidatus, Mycobacterium, Rodopila, and Streptomyces, while opportunistic pathogens such as Streptococcus, Escherichia, Klebsiella, Neisseria, Rhizobium, and Salmonella were abundant in the control diet-fed shrimp. Also, lipopeptide diet-fed shrimp were found to have a high abundance of ammonia and nitrogen oxidizing bacteria, which are essential pollutant degraders. Therefore, the study reveals that the dietary supplementation of lipopeptide in shrimp aquaculture could positively modulate the gut microbiome and enhance the shrimp's overall health and immunity in an eco-friendly manner.

Epidemiological patterns and incidence of bio-, sero- and phage types of Vibrio cholerae in Hyderabad, India, during 1971-1984.

During 1971-1984 out of 44,762 gastroenteritis cases bacteriologically examined, 4240 (9.5%) Vibrio cholerae were isolated in Hyderabad, India. Out of them 1329 (31.3%) were classical and 2911 (68.7%) were el-tor biotypes. The changeover from classical to el-tor cholera was observed in Hyderabad during 1975 and persisted. During this 14 year period four major outbreaks with V. cholerae serogroup O1 Ogawa, V. cholerae biotype el-tor serogroup O1 Ogawa were observed. Phage types 1, 2 and 4 were prevalent during the classical period and types 2 and 4 during the el-tor period. Of the cholera patients, 67% were under 30 years of age with no significant difference in the incidence among females (51.4%) and males (48.6%). The outbreaks were of protracted pattern with only few cases per day or week with peak incidence during monsoon (May-August). Community of the low socio-economic strata was the most susceptible group. Five zones situated at the outlet of the Moosi river in the downhill were recorded as extensive cholera transmission zones and two of them were the primary foci of infection. The severity of the infection was found directly related to the average rainfall during the year leading to the sewage stagnation in the downhill.

Production of toxic shock syndrome toxin-1 (TSST-1) associated with Staphylococcus aureus from a pyogenic skin infection.

Toxic Shock Syndrome Toxin-1 (TSST-1) producing Staphylococcus aureus associated with TSS was isolated from an abscess on buttock, from a two-year-old male child suffering from diarrhoea, high fever and shock. The isolate was subclassified into S. aureus var. hominis of CV type-D, and was lysed by phage 75 of Group-III. It was multidrug resistant, exhibited double ring (DR) CVRT pattern and also produced enterotoxin-C (SE-C). Out of 217 S. aureus strains from pyodermas, clinical sources, food poisonings and dairy foods, 139 (64.1%) produced enterotoxin. SE-C as single (33.8%) or in combinations (25.2%) was common enterotoxin. None of these strains produced TSST-1.