Sequencing and phylogenetic analysis of the stn gene of Salmonella species isolated from different environmental sources at Lake Qarun protectorate: The role of migratory birds and public health importance

Background and Aim: Salmonella causes most foodborne bacterial illnesses worldwide. It is found in various hosts, including pets, farm animals, and wild animals, as well as the environment. This study aimed to examine the epidemiological relationship between Salmonella isolates from aquatic environments and those from other avian hosts. Materials and Methods: The study examined 12 water samples, 210 aquatic animals, and 45 migratory aquatic bird samples collected from the protected area of Lake Qarun in El-Fayoum Governorate, Egypt, during migration seasons from different waterfowl migration areas (from October 2018 to January 2019). In addition, 45 fecal samples from domestic chickens were collected from the same geographic location from poultry farms. Bacteriological examination and polymerase chain reaction assay of two virulence genes (i.e., invA and stn) were performed to isolate and identify Salmonella. Results: Salmonella was isolated from 58.3% (7/12) of Lake Qarun water samples, 13.3% (6/45) of migratory waterfowl, 6.6% of (3/45) of chickens (Gallus gallus domesticus), and 4.3% (3/70) of fish and pooled brine shrimp. In migratory aquatic bird species that were sampled, Salmonella were isolated from 23.1% (3/13) of Eurasian coot (Fulica atra), 12.5%, (1/8) of green-winged teal (Anas cardolinesis), 10% (2/20) of northern shoveler (Spatula clypeata), and 0% (0/4) of mallard duck (Anas platyrhynchos). In 35 Tilapia, Salmonella was isolated by (8.6%) 5.7% of external surfaces, 2.85% from the intestine, and 0% from the muscle. No Salmonella was isolated from the 175 brine shrimp samples. Phylogenetic analysis using the stn genes of Salmonella isolated from the aquatic environment, migratory aquatic birds, and chicken showed a strong association between these isolates. In addition, a higher nucleotide identity percentage was observed between the sequences recovered from migratory aquatic birds and Lake Qarun water samples. Conclusion: Salmonella distribution was confirmed through migratory aquatic birds, based on our phylogeny tree analysis, Salmonella considered a likely carrier of zoonotic bacterial pathogens. Furthermore, the close relationship between chicken and fish sequences highlights the scenarios of using chicken manure in fish farms and its public health implications. The presence of Salmonella in different environmental sources spotlights the urgent need to control and break down its epidemiological cycle.

Structure of the 4-O-[1-Carboxyethyl]-d-Mannose-Containing O-Specific Polysaccharide of a Halophilic Bacterium Salinivibrio sp. EG9S8QL

The moderately halophilic strain Salinivibrio sp. EG9S8QL was isolated among 11 halophilic strains from saline mud (Emisal Salt Company, Lake Qarun, Fayoum, Egypt). The lipopolysaccharide was extracted from dried cells of Salinivibrio sp. EG9S8QL by the phenol–water procedure. The OPS was obtained by mild acid hydrolysis of the lipopolysaccharide and was studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments. The OPS was found to be composed of linear tetrasaccharide repeating units of the following structure: →2)-β-Manp4Lac-(1→3)-α-ManpNAc-(1→3)-β-Rhap-(1→4)-α-GlcpNAc-(1→, where Manp4Lac is 4-O-[1-carboxyethyl]mannose.

Bioremediation potential of a halophilic bacterium Chromohalobacter salexigens EG1QL3: exopolysaccharide production, crude oil degradation, and heavy metal tolerance

Based on biochemical and phylogenetic analyses, isolated from a salt sample from Lake Qarun (Egypt) a halophilic strain EG1QL3 was identified as Chromohalobacter salexigens. The abilities of EG1QL3 to produce an extracellular polysaccharide, degrade oil, and resist to heavy metals were revealed.