Antibacterial activity of a marine bacterium against pathogenic and environmental isolates of vibrio species

The marine environment covers three quarters of the surface of the planet is estimated to be home to more than 80% of life and yet it remains largely unexplored. The rich diversity of marine flora and fauna and its adaptation to the harsh marine environment coupled with new developments in biotechnology, has opened up a new exciting vista for extraction of bioactive products of use in medicine. In this study inhibitory activity of a marine bacterium isolated from gut of ribbonfish was studied against pathogenic and environmental isolates of Vibrio species. This strain was identified as Pseudomonas stutzeri and it was found active against V. harveyi (luminescent bacteria), V. cholerae, V. alginolyticus, V. damseal, V. fluvialis. The antibacterial substance produced by Pseudomonas stutzeri was soluble in organic solvent and closely bound to external surface of bacterial cells. Reduction of the absorbance of the V. cholera cell suspension was observed when log phase cells of V. cholerae were treated with MIC and 4xMIC concentration of crude extract of Pseudomonas stutzeri.

Pathogenesis of Yersinia ruckeri-like isolates and compared with Streptococcus sp. in rainbow trout, Onchorhyncus mykiss

Pathogenesis of an isolate of Yersinia rukeri-like bacterium was studied in rainbow trout weighting 8-12 g at 20C and acceptable water quality for 20 days.

Distribution and occurrence of bacterial fish diseases in the different cultural facilities of Lake Kainji area

Fish farming practices in the Lake Kainji Area of Nigeria are categorized under seven main cultural facilities, namely, earthen ponds/reservoirs, indoor/outdoor concrete tanks, plastic tanks, floating cages/hapas, aquaria, sewage and feral conditions. The presence of Bacteria isolates associated with diseased fish conditions varied significantly (P<0.05) with different cultural facilities. The highest bacteria isolates and bacterial disease incidence, 33% and 46% respectively, was associated with diseased fish in the indoor/outdoor concrete tanks. The least incidence of bacteria isolates (3.5%) and blue bacterial disease (3%) was associated with diseased fish in the aquaria and feral conditions. Nine Gram-negative and two Gram-positive bacteria genera were isolated during this investigation. Pseudomonas spp. (23.6%) and Staphylococcus spp. (14.3%), were the predominant Gram-negative and Gram-positive bacteria genera in the different cultural facilities, respectively. This paper highlights the relevance of occurrence and distribution of bacteria isolates associated with diseased fish to bacterial fish diseases under different cultural facilities

Tuberculosis in seals caused by a novel member of the Mycobacterium tuberculosis complex: Mycobacterium pinnipedii sp. nov.

A comparison of Mycobacterium tuberculosis complex isolates from seals (pinnipeds) in Australia, Argentina, Uruguay, Great Britain and New Zealand was undertaken to determine their relationships to each other and their taxonomic position within the complex. Isolates from 30 cases of tuberculosis in six species of pinniped and seven related isolates were compared to representative and standard strains of the M. tuberculosis complex. The seal isolates could be distinguished from other members of the M. tuberculosis complex, including the recently defined ‘Mycobacterium canettii’ and ‘Mycobacterium caprae’, on the basis of host preference and phenotypic and genetic tests. Pinnipeds appear to be the natural host for this ‘seal bacillus’, although the organism is also pathogenic in guinea pigs, rabbits, humans, Brazilian tapir (Tapirus terrestris) and, possibly, cattle. Infection caused by the seal bacillus is predominantly associated with granulomatous lesions in the peripheral lymph nodes, lungs, pleura, spleen and peritoneum. Cases of disseminated disease have been found. As with other members of the M. tuberculosis complex, aerosols are the most likely route of transmission. The name Mycobacterium pinnipedii sp. nov. is proposed for this novel member of the M. tuberculosis ...

Study on the intestinal bacteria of Labeo rohita (Ham.)

The quantitative and qualitative aspects of intestinal bacteria of rohu fish (Labeo rohita) showed that total viable count of bacteria ranged from 9.9 x 106 to 1.4 x 107 CFU/g of intestine in different age groups of fish. The bacterial load was highest in the month of July and lowest in January. The genera of the isolates from intestine included Coryneform, Micrococcus, Flavobacterium, Cytophaga, Achromobacter, Aeromonas Enterobacteriaceae and Vibrio. Coryneform was the dominant group throughout the study period followed by Micrococcus and Enterobacteriaceae. Marked variations in the bacterial load and generic composition of intestinal bacteria were evident during the study period in different age groups of rohu fish.

Pathogenicity of Aeromonas sobria to Thai silver barb (Barbodes gonionotus Bleeker) and its sensitivity to some antibiotic agents

Five isolates of Aeromonas sobria, collected from the diseased fish were selected for detection the pathogenicity following water-born infection method on silver barbs (Barbodes gonionotus) at the selected exposure dose 2.5x10⁸ CFU/ml which was standardized by preliminary test. In the experimental condition lesion and mortality were found in fishes. Among the isolate, Ass17 Ass19, Ass31 and Ass36 were successfully infected 20-60% fishes. Another isolate Ass20 was found non-pathogenic. Drug sensitivity test was performed by six antibiotics viz. Oxytetracycline, Oxolinic acid, Chloramphenicol, Stilphamethozazole, Streptomycin, Erythromycin. All the isolates showed variable reaction patterns to antibiotics. Most of the isolates were found sensitive to Oxytetracycline (OT), Oxolinic acid (OA) and Chloramphenicol (C) but resistance to Erythromycin and Sulphamethoxazole (SXT). Isolate Ass31 found resistant to Oxolinic acid.

The nature of the aerobic gastrointestinal bacteria of cichlid fish Sarotherodon mossambicus (Peters) and Tilapia nilotica (Linnaeus) grown under captivity

Bacteriological examination of the gastrointestinal microflora of 2 freshwater cichlid fish species (Sarotherodon mossambicus and Tilapia nilotica ) was performed, resulting in the bacteria enumeration of total viable counts of 1.06x10⁷/g and 7.75x10⁷/g of gastro-bacteria intestinal tract plus contents (wet weight) respectively, by aerobic incubation at 30+1°C. The majority (78%) of the total gut isolates from both fish species was Gram positive mesophilic which is characteristic of the higher ambient temperature in the tropics. These isolates were fastidious in their nutritional requirements and together with the rest are isogenous to bacteria autochthonous to soil and water. The occurrence of such organisms is attributed to the feeding habits of these fish. The gastrointestinal bacteria isolated in this study are transient residents but not "indigenous" in these cichlid fish.