Fatty Acids-Enriched Fractions of Hermetia illucens (Black Soldier Fly) Larvae Fat Can Combat MDR Pathogenic Fish Bacteria Aeromonas spp.

Aeromonas spp. cause many diseases in aquaculture habitats. Hermetia illucens (Hi) larvae were used as feed-in aquacultures and in eradicating pathogenic fish bacteria. In the present study, we applied consecutive extractions of the same biomass of BSFL fat using the acidic water–methanol solution. The major constituents of the sequential extracts (SEs) were free fatty acids (FFAs), and fatty acids derivatives as identified by gas chromatography spectrometry (GC-MS). Our improved procedure enabled gradual enrichment in the unsaturated fatty acids (USFAs) content in our SEs. The present study aimed to compare the composition and antimicrobial properties of SEs. Among actual fish pathogens, A. hydrophila and A. salmonicida demonstrated multiple drug resistance (MDR) against different recommended standard antibiotics: A. salmonicida was resistant to six, while A. hydrophila was resistant to four antibiotics from ten used in the present study. For the first time, we demonstrated the high dose-dependent antibacterial activity of each SE against Aeromonas spp., especially MDR A. salmonicida. The bacteriostatic and bactericidal (MIC/MBC) activity of SEs was significantly enhanced through the sequential extractions. The third sequential extract (AWME3) possessed the highest activity against Aeromonas spp.: inhibition zone diameters were in the range (21.47 ± 0.14–20.83 ± 0.22 mm) at a concentration of 40 mg/mL, MIC values ranged between 0.09 and 0.38 mg/mL for A. hydrophila and A. salmonicida, respectively. AWME3 MBC values recorded 0.19 and 0.38 mg/mL, while MIC50 values were 0.065 ± 0.004 and 0.22 ± 0.005 mg/mL against A. hydrophila and A. salmonicida, respectively. Thus, the larvae fat from Hermitia illucens may serve as an excellent reservoir of bioactive molecules with good capacity to eradicate the multidrug-resistant bacteria, having promising potential for practical application in the aquaculture field.

A new probiotic candidate bacterium from human milk: Limosilactobacillus vaginalis MA-10

The probiotic and technological potentials of lactic acid bacteria originating from human milk are becoming a remarkable research area. In the present study, Limosilactobacillus vaginalis MA-10 isolated from human milk was investigated in vitro for its probiotic and technological aspects. According to the results obtained in the study, MA-10 strain exhibited non-haemolytic activity and various degrees of sensitivity to most of the tested antibiotics. The strain showed good resistance to the gastrointestinal system and maintained its viability under these conditions. Its antimicrobial activity against human or clinical bacterial and fungal microorganisms and fish bacteria was determined in the range of 2.38–11.22 mm. The MA-10 strain was able to assimilate cholesterol ranging from 31.42 to 82.30%. The strain showed 9.34% ferrous-ion chelating and 32% DPPH free radical scavenging activities. These initial results from the present study confirm that L. vaginalis MA-10 may be a new source with appropriated probiotic and technological traits for various industries, and further in vivo assays.Due to the limited number of studies on L. vaginalis strains originated from human breast milk in the literature, the data obtained in this study are thought to be important for revealing the basic probiotic properties of the strain.

Comparison Study Of Bacteria On Pangasius djambal In Ponds And River In Pagelaran Lampung

Pangasius djambal is one of the popular fish. The obstacle in this fish culture is the presence of bacterial attack, which is thought to originate from the waters where the fish live. This study aims to determine the differences in the number of bacteria found in the body of P djambal that are cultivated in ponds and those that live in rivers. Based on research, it is known that the number of bacteria found in the body of fish originating from rivers is more than the number of bacteria originating from ponds. The results showed the number of bacteria in the gills of fish from river reached 250 x 107 Cfu/g and in mucus 199 x 107 Cfu/g. While the number of fish bacteria originating from ponds in the gills section is 204 x 107 Cfu/g and in the mucus section is 131x107 Cfu/g.

Plant essential oils against bacteria isolated from fish: an in vitro screening and in vivo efficacy of Lippia origanoides

ABSTRACT: The use of natural products, such as essential oils (EOs), is a potential novel approach to treat fish bacterial infections with a lower risk of developing resistance. There has been a number of studies reporting the activity of EOs as those obtained from the species Achyrocline satureioides, Aniba parviflora, Aniba rosaeodora, Anthemis nobilis, Conobea scoparioides, Cupressus sempervirens, Illicium verum, Lippia origanoides, and Melaleuca alternifolia against bacteria. However, there are few studies investigating the effect of these EOs against fish bacteria. Therefore, the aim of this study was to evaluate the in vitro antibacterial activity of EOs against the following fish bacteria, Aeromonas hydrophila, Citrobacter freundii, and Raoultella ornithinolytica. Additionally, the in vivo antibacterial activity of the EO L. origanoides was evaluated against experimentally induced A. hydrophila infection of silver catfish (Rhamdia quelen). The EO of L. origanoides was chosen as it showed the highest in vitro antibacterial activity, with minimum inhibitory concentrations ranging from 0.2 to 0.8 mg mL-1. This EO also presented a therapeutic success of 58.33%, on a 30 day A. hydrophila infection. Therefore, we suggested that the EO of L. origanoides may be a viable alternative as a treatment for A. hydrophila infection.

Morphological and biochemical characterization of two fish pathogenic bacteria: Aeromonas salmonicida and Yersinia ruckeri for rapid diagnosis of fish disease

Aeromonas salmonicida and Yersinia ruckeri are two common pathogenic fish bacteria responsible for furunculosis and Enteric Red Mouth disease (ERM), respectively. For the characterization of these two pathogens, a series of morphological (pigmentation, hemolyse, motility and body shape), biochemical tests (Gram staining, catalase, oxidase and API 20E strips) and a soft ionization technique (MALDI-TOF/MS) were performed in the laboratory. Pigmentation, motility, hemolysis and body shape was used as a preliminary identification of the bacteria. Both of the species were identified with the entire biochemical test without any doubt except API20E strips test. Although the API profile of A. salmonicida (0006104) was identified with high confidence (99.6%), but Y. ruckeri was misidentified as Vibrio mimicus. There are strong supports against Vibrio mimicus as it is a human pathogen, grow at a temperature more than 20oC, motile and oxidase positive bacteria. The Y. ruckeri is a non-motile fish bacteria and oxidase negative which are consistent with the study results. Agglutination test with Bionor Mono kit was also identified the bacteria as Y. ruckeri. For rapid diagnosis of infectious disease, accurate identification of pathogen is very important for commercial aquaculture.Asian J. Med. Biol. Res. March 2017, 3(1): 44-51