Isolation and Characterization of Bacteriophages Active against Pseudomonas aeruginosa Strains Isolated from Diabetic Foot Infections

Diabetic foot infection has become one of the most important public health concerns and is a growing problem. Pseudomonas aeruginosa is an important opportunistic multidrug-resistant bacterium in diabetic foot infections. In the absence of antibiotics active against MDR strains of P. aeruginosa, phage therapy becomes a key way to deal with P. aeruginosa infections. Out of 185 samples collected from diabetic foot ulcers, 50 (27.02%) isolates were identified as P. aeruginosa. The incidence increases with older ages, and males (n=34, 68%) predominated in all age groups. The tested isolates showed maximum susceptibility towards colistin (80%), imipenem (72%), amikacin (66%), and piperacillin/tazobactam (62%), while these isolates showed moderate susceptibility towards ceftazidime (58%), cefepime (52%) and gentamicin (46%). However, it showed complete resistance (100%) to ampicillin, cefaclor, and sulphamethoxazole/trimethoprim and highly resistance to clindamycin (90%) and amoxicillin/clavulanic acid (84%). Two bacteriophages (ϕPAE1 and ϕPAE2) isolated from sewage samples showed a broad host range against P. aeruginosaa clinical strains. ϕPAE2 infected 74% (37/50) and ϕPAE2 58% (29/50). Furthermore, both phages were host-specific, infecting only P. aeruginosa strains and could not infect other bacterial species in the cross-infectivity studies. Both phages were found to be relatively heat stable as over a period of 1 h, after exposure to a temperature range of 37-50°C, no significant loss in phage activity was observed. On the other hand, the lowest activity was observed at 70°C (39.15%) for ϕPAE1 whereas it was inactivated at 75°C while the lowest activity was observed at 75°C (38.01%) for ϕPAE2 whereas it was inactivated at 80°C. Isolated phages were able to survive and lyse host bacteria over a wide pH range. The optimum pH range for infection was from 6 to 8. Furthermore, ϕPAE1 lost its ability to lyses at pH 2, 3, 11 and 12, whereas; ϕPAE2 lost its infectivity at pH 2, 3 and 12. Chloroform was the most effective solvent that reduced the infectivity of ϕPAE1 and ϕPAE2 to 63.27% and 77.88%, respectively. On the other hand, petroleum ether showed the lowest effect on the infectivity of ϕPAE1 and ϕPAE2; it was reduced to 96.4% and 97.48%, respectively, followed by acetone and ethyl alcohol. The ability of P. aeruginosa phages to form plaques after different storage temperatures (4°C, 30°C, 37°C and 44°C) for a month was slightly affected. The storage of ϕPAE1 and ϕPAE2 at 4ºC showed the least effect on its infectivity, and the storage at 44ºC showed the highest reduction in its infectivity. Moreover, Phage counts were slightly decreased by increasing storage period and temperature.

Changes in the feeding behavior and habitat use of the desert hedgehog Paraechinus aethiopicus (Ehrenberg 1832, Eulipotyphla: Erinaceidae), in Saudi Arabia

Due to the urbanization and human invasion of the natural environments, great changes have been occurred on the food composition and feeding ecology of several animals especially those are sharing human his habitat in fields, wadis and gardens. The desert hedgehogs Paraechinus aethiopicus populations inhabiting different localities in Saudi Arabia were studied by using stomach contents analysis between February 2015 and October 2019. Precise analysis of stomach contents of 55 hedgehogs showed that the food of P. aethiopicus is highly diverse and highly influenced with effect of human on the environment including cooked rice, insects, plant materials, eggshells, worms, garbage and remnants of mammals and birds. Diet composition showed seasonal variations that are apparently associated with changes in the availability of different food items. The present results clearly showed that P. aethiopicus is an omnivorous mammal, capable of adapting to a great variety of dietary compositions in the study sites.

Myristica fragrans Kernels Prevent Paracetamol-Induced Hepatotoxicity by Inducing Anti-Apoptotic Genes and Nrf2/HO-1 Pathway

Paracetamol is responsible for acute liver failure in humans and experimental animals when taken at high doses and transformed into a reactive metabolite by the liver cytochrome P450. On the other hand, nutmeg is rich with many phytochemical ingredients that are known for their ability to inhibit cytochrome P450. Hence, the present experiment was aimed at studying the hepatoprotective effect of Myristica fragrans (nutmeg), kernel extract (MFKE) in respect to paracetamol (acetaminophen; N-acetyl-p-amino-phenol (APAP))-induced hepatotoxicity in rats, focusing on its antioxidant, anti-inflammatory, and anti-apoptotic activities. Liver toxicity was induced in rats by a single oral administration of APAP (2 g/kg). To evaluate the hepatoprotective effect of MFKE against this APAP-induced hepatotoxicity, rats were pre-treated with either oral administration of MFKE at 300 mg/kg daily for seven days or silymarin at 50 mg/kg as a standard hepatoprotective agent. APAP intoxication caused a drastic elevation in liver function markers (transaminases, alkaline phosphatase, and total bilirubin), oxidative stress indicators (lipid peroxidation and nitric oxide), inflammatory biomarkers (tumour necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and nuclear factor ĸB) and the pro-apoptotic BCL2 Associated X (Bax) and caspases-3 genes. Furthermore, analyses of rat liver tissue revealed that APAP significantly depleted glutathione and inhibited the activities of antioxidant enzymes in addition to downregulating two key anti-apoptotic genes: Cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein (c-FLIP) and B-cell lymphoma 2 (Bcl-2). Pre-treatment with MFKE, however, attenuated APAP-induced liver toxicity by reversing all of these toxicity biomarkers. This hepatoprotective effect of MFKE was further confirmed by improvement in histopathological findings. Interestingly, the hepatoprotective effect of MFKE was comparable to that offered by the reference hepatoprotector, silymarin. In conclusion, our results revealed that MFKE had antioxidant, anti-inflammatory, and anti-apoptotic properties, and it is suggested that this hepatoprotective effect could be linked to its ability to promote the nuclear factor erythroid 2⁻related factor 2 (Nrf2)/antioxidant responsive element (ARE) pathway.

Susceptibility of mice strains to oxidative stress and neurotransmitter activity induced by Plasmodium berghei

This study investigated the susceptibility of female C57Bl/6 and Swiss Albino mice to oxidative stress and neurotransmitters activity induced by Plasmodium berghei. On day 9 p.i. with P. berghei infected erythrocytes, the mice reduced in weight. This weight loss was markedly higher in SW mice and reached about −14%. Also, the infection was able to cause oxidative damage to the brain tissue. Catalase activity as well as glutathione, malondialdehyde and nitric oxide levels were different in the two mice strains. Moreover, the brain content of neurotransmitters, epinephrine, norepinephrine, dopamine and serotonin in mice brain was higher in SW mice than B6 mice. We concluded that, the strain of mice is one factor that could alter the response of mice to P. berghei infection.