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.

The preparation of A purified immunogenic pertactin from B. pertussis.

Pertactin, an outer membrane protein of Bordetella pertussis, was purified to apparent homogeneity. The purified pertactin was first extracted from the B. pertussis cells (strain 165) by heating for 1 h at 60 degrees C, followed by DEAE-Sepharose and Affi-Gel Blue chromatography. The purified pertactin migrated as a single band of 69-kDa and a pl of 5.9 and retains a high immunogenicity. The rabbit anti- pertactin antisera shows high specificity in ELISA. The purified pertactin is a potential candidate as immunogen for preparation of diagnostic reagents and as a vaccine component.

Spectrophotometric determinations of 3-dimethylaminomethylkhellin hydrochloride and khellin.

Spectrophotometric assays are proposed for the determination of 3-dimethylaminomethylkhellin hydrochloride and khellin in bulk chemical and dosage forms. The acid dye method, using methyl orange at pH5, is applied to assay the amine in the form of an ion-pair extractable in chloroform with maximum abosrbance at 420 nm. The perchloric acid method, depending on formation and extraction of the oxonium salts of both compounds, is used to assay the amine and khellin at 333 or 430 nm and at 325 or 410 nm, respectively. The reineckate method can be used to assay the amine as the reineckate derivative in acetone with maximum absorbance at 530 nm. However, small amounts of the amine (1.5--3 mg) can be determined as the reineckate in methanol with maximum absorbance at 245 nm. Stability determination of the two compounds can be done by the acid dye and perchloric acid methods. The three methods are sufficiently accurate, sensitive, and precise.

Preparation and skin-photosensitizing activity of substituted psoralens.

8-Monosubstituted and 5,8-disubstituted psoralen derivatives were prepared, and their skin-photosensitizing activity was evaluated. The results were correlated in terms of molecular configuration, and 8-allyloxypsoralen can be considered was a new agent of potent photodynamic activity.

Synthesis and screening of some substituted 3.5-dioxopyrazolidines.

Seven new 3.5-dioxopyrazolidine derivatives, incorporating in their molecule a p-substituted benzoyl grouping, were synthesized. The preliminary screening of four selected compounds showed that 1-phenyl-2-[p-nitrobenzoyl]-4.4-diethyl-3.5-dioxopyrazolidine possesses a low order of antiinflammatory activity.

Synthesis of some new phenothiazine derivatives of expected medicinal value.

2-Chloroacetyl phenothiazines were reacted with certain phenols and salts of some acids under different conditions to yield 2-substituted acetylphenothiazines. Another series of 10-substituted phenothiazines was synthesized by treatment of 10-chloroacetylphenothiazine with either the appropriate amines or salts of the respective acids. The optimum experimental conditions for the preparation of 2-chloroacetyl-10-acetyl-phenothiazine by Friedel-Crafts reaction were studied. Also N-chloroacetyl-o-aminophenol was synthesized in high yield by a simple method. The preliminary pharmacological screening showed that two of these compounds possess a low order of tranquillizing activity.