Isolation of Multidrug-Resistant Helicobacter pylori from Wild Houseflies Musca domestica with a New Perspective for the Treatment

Background: High frequency of Helicobacter pylori infection and the unknown mode of transmission prompted us to investigate H. pylori-wild housefly relationship. H. pylori causes chronic gastritis, peptic ulcers, and stomach cancer. H. pylori persists in the gut of the experimentally infected houseflies. The existence of H. pylori strains isolated from wild houseflies, on the other hand, has never been documented. Materials and Methods: In this study, 902 wild houseflies from different sites were identified as Musca domestica, then 60 flies were screened by traditional microbiological techniques and H. pylori-specific 16S rRNA gene. The antibiotic resistance (ART) was investigated phenotypically. Wild housefly gut bacterial isolates were further evaluated genotypically to have 23S rRNA gene mutation related to clarithromycin resistance. To find efficient therapeutic alternatives, the potency of three plant extracts (garlic, ginger, and lemon) and the wasp, Vespa orientalis venom was evaluated against H. pylori. The cytotoxic effect of the crude wasp venom, the most potent extract, against Vero and Colon cancer (Caco2) cell lines was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results: All isolates from houseflies were positive. The isolated bacteria have variable resistance to frequently used antibiotics in all isolates. Minimum inhibitory concentration values of 15.625 mg/mL for both ginger and lemon extracts, 7.8125 mg/mL for garlic extract, and 0.0313 mg/mL for wasp venom were recorded. Wasp venom has the most potent antibacterial activity compared with the four antibiotics that are currently used in therapies against H. pylori. Conclusion: We conclude that wild houseflies can play a role in disseminating H. pylori. The housefly gut may be a suitable environment for the horizontal transfer of ART genes among its associated microbiome and H. pylori. Wasp venom proved its potential activity as a new and effective anti-H. pylori drug for both therapeutic and preventative usage.

Antimicrobial Profile of Actinomycin D Analogs Secreted by Egyptian Desert Streptomyces sp. DH7

Egyptian deserts are an underexplored ecological niche, especially the Sinai Peninsula. In our recent study, we explored this extreme environment and shed light on the bioactive capabilities of desert Actinobacteria isolated from Sinai. Fifty desert Actinobacteria were isolated from the Sinai desert using mineral salt media, basal media, and starch casein media. The filtrate of Streptomyces sp. DH 7 displayed a high inhibitory effect against multidrug-resistant Staphylococcus aureus (MRSA) strains. The 16S rDNA sequencing confirmed that isolate DH7 belongs to the genus Streptomyces. The NJ phylogenetic tree showed relatedness to the Streptomyces flavofuscus strain NRRL B-2594 and Streptomyces pratensis strain ch24. The minimum inhibitory concentrations against MRSA were 16 and 32 μg/μL. Chemical investigation of the ethyl acetate extract of Streptomyces sp. DH7 led to the isolation and purification of natural products 1-4. Structure elucidation of the purified compounds was performed using detailed spectroscopic analysis including 1 and 2D NMR, and ESI-MS spectrometry. To the best of our knowledge, this is the first report for the isolation of compounds 1-4 from a natural source, while synthetic analogs were previously reported in the literature. Compounds 3-4 were identified as actinomycin D analogues and this is the first report for the production of actinomycin D analogs from the Sinai desert with an inhibitory effect against MRSA. We indorse further study for this analog that can develop enhanced antimicrobial activities. We confirm that the desert ecosystems in Egypt are rich sources of antibiotic-producing Actinobacteria.

Statistical factorial designs for optimum production of thermostable α-amylase by the degradative bacterium Parageobacillus thermoglucosidasius Pharon1 isolated from Sinai, Egypt

BACKGROUND

This study aimed to isolate potent thermophilic and amylolytic bacteria from a hot spring of Pharaoh's bath, Sinai, Egypt, and screen its degradative activity. The amylolytic activity was further optimized using a statistical full factorial design followed by response surface methodology.

RESULTS

A thermophilic bacterium was isolated from the hot spring of Pharaoh's Bath, Sinai, Egypt. The isolate produced amylase, cellulase, and caseinase and was identified by 16S rRNA gene sequencing as Parageobacillus thermoglucosidasius Pharon1 (MG965879). A growth medium containing 1% soluble starch was found to optimize the amylase production. Dinitrosalycalic acid method (DNS) was used to estimate the amount of reducing sugar produced. Statistical full factorial and response surface designs were employed to optimize physical variables affecting the α-amylase production and determine the significant interactions of the studied variables during the fermentation process. According to the results obtained by the response optimizer, the maximum amylase activity reached 76.07 U/mL/ min at 54.1°C, pH 5.6 after 98.5 h incubation under aerobic conditions. Moreover, the produced enzyme was thermostable and retained most of its activity when exposed to a high temperature of 100°C for 120 min. Maximum enzyme activity was attained when the enzyme was incubated at 70°C for 30 min.

CONCLUSIONS

This is the first report of the production of thermostable α-amylase by the potent thermophilic Parageobacillus thermoglucosidasius. The enzyme endured extreme conditions of temperature and pH which are important criteria for commercial and industrial applications.