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Biomedical subjects

S Hafiz

Publications and source records attributed to S Hafiz.

At least 73 records · Page 4Linked to original sources

Susceptibility of Haemophilus ducreyi to ampicillin and sulbactam in vitro.

The MICs of ampicillin, ampicillin plus sulbactam in equal proportions, and a range of ampicillin concentrations with a constant 0.5 micrograms/ml concentration of sulbactam were determined for 66 strains of Haemophilus ducreyi by an agar dilution technique with standardized inocula prepared by ultrasonication. Fifty-five strains were susceptible to ampicillin alone (MIC range, 0.06 to 1 microgram/ml). The MICs for the 11 resistant strains were (micrograms per milliliter): range, 8 to greater than 16; MIC for 50% of the strains tested (MIC50), greater than 16; MIC90, greater than 16; 8 of them produced beta-lactamase. In the presence of an equal concentration of sulbactam, the MICs for ampicillin-resistant strains were lowered to (micrograms per milliliter): range, 0.125 to 2; MIC50, 0.25; MIC90, 1. In the presence of a fixed 0.5-micrograms/ml concentration of sulbactam, the MICs for the resistant strains were (micrograms per milliliter): range, 0.125 to 2; MIC50, 0.125; MIC90, 0.25. Sulbactam-ampicillin appears to be suitable for the treatment of H. ducreyi infections, especially those caused by ampicillin-resistant strains.

Ampicillin↗

Susceptibility of Haemophilus ducreyi to spectinomycin in vitro.

Using an agar dilution technique with standardised inocula prepared by ultrasonication, the minimum inhibitory concentrations (MICs) of spectinomycin were determined for 66 strains of Haemophilus ducreyi, eight of which were beta lactamase producers. All strains were sensitive to concentrations of spectinomycin, which were well within the therapeutic ranges attained with normal dosage. The MIC50 and MIC90 were 8 mg/l, (range 0.007-16 mg/l).

Cells, Cultured↗

Effect of microwave energy on the metabolism of Enterobacteriaceae.

The effect of microwave irradiation on the metabolism of 94 strains of Enterobacteriaceae was studied. Sixteen substrates were used and the results obtained with microwave irradiation were compared with those given by conventional biochemical tests. There was good correlation between the methods but not sufficient to enable accurate identification of unknown species. However, microwave irradiation considerably increased the enzymatic activity of bacterial suspensions and the results obtained could form the basis for a rapid method of microbial identification.

Carbohydrate Metabolism↗

Anaerobic bacteria and herpes simplex virus in genital ulceration.

Of 91 patients with genital ulceration, herpes simplex virus was isolated from 52 (57%) and Haemophilus ducreyi from 12 (13%); none had syphilis. The difference in incidence of other aerobes in patients and controls was not significant. Anaerobes, predominantly Bacteroides spp, were isolated from a large proportion (77%) of men and women patients with ulcers but from few control men. The most common anaerobic species were B asaccharolyticus and B ureolyticus, with fewer isolates of the melaninogenicus/oralis group. The bacterial flora of herpetic and non-herpetic ulcers were similar, but Candida albicans was isolated significantly more often from non-herpetic ulcers. Anaerobic bacteria may contribute to the pathogenesis of genital ulcers.

Adolescent↗

Sheffield medium for cultivation of Haemophilus ducreyi.

Our interest in the role of Haemophilus ducreyi in genital ulceration led us to examine the various media commonly used for the cultivation of the organism. We describe an improved medium for the routine isolation of H ducreyi. In comparative studies using 50 test strains originally isolated in the United Kingdom, Canada, the United States of America, and Kenya, the new medium proved superior to three standard media in requiring a shorter incubation period to first visible growth, giving larger colonies in the same period, and making possible a starch aggregation test which we have found helpful in the presumptive identification of H ducreyi from clinical material.

Culture Media↗

Actinomyces in the female genital tract. A preliminary report.

Actinomyces spp were isolated by culture of endocervical specimens from two groups of women attending the department of genitourinary medicine of the Royal Hallamshire Hospital, Sheffield. The first group consisted of 78 users of intrauterine contraceptive devices (IUCD) of whom 20 (25.6%) were culture positive. The second group contained 63 women using various forms of contraception 12 (19%) of whom were culture positive. None of these 12 women had an IUCD or foreign body in situ. The results suggest that Actinomyces spp may be part of the commensal flora of the genital tract in some women.

Actinomyces↗

Haemophilus ducreyi infections--time for reappraisal.

As the literature on Haemophilus ducreyi and clinical chancroid is reviewed, it becomes obvious that many significant findings have been forgotten over the years. As a result, from the time of Ducrey's original description of the organism in 1890 until about 1977, both clinical and laboratory experts in the United Kingdom believed that H. ducreyi infections were rare, generally acquired abroad, and almost impossible to confirm in the routine laboratory! In consequence it was a common view that it was not worth looking for H. ducreyi until all other possible causes of genital ulceration had been excluded. Moreover, the search for such an infection stopped as soon as any other cause for the patient's lesions had been found. A decision to ignore this 'rule' in Sheffield led to our looking for H. ducreyi in specimens from an unselected series of patients with genital ulceration including a number with herpes genitalis infections. The surprise finding of H. ducreyi in circumstances suggesting that it was a secondary invader made us re-examine the whole question of H. ducreyi infections and chancroid and wonder if the same organism can act as a primary pathogen and as a secondary invader. An account of the media and methods we used and of the characteristics of the organism is presented. In an attempt to find out more about the characteristic coherent colonies of H. ducreyi we studied them with the scanning electron microscope. It is clear that the whole subject of H. ducreyi infections has been neglected in the United Kingdom, but we believe that interest has now been aroused and progress will surely follow. Some areas for further investigation are suggested.

Chancroid↗

The effect of benzyl penicillin on the ultrastructure of Neisseria gonorrhoeae.

Electron microscopy of Neisseria gonorrhoeae grown on solid medium with a subinhibitory concentration of penicillin suggested that the amount of penicillin reaching each pair of gonococci was different, as illustrated by the ultrastructural appearance of N, gonorrhoeae cells in the colony. This supports the view that the concentration of penicillin in different parts of the colony is not uniform, causing some cells to lyse while the others remain intact.

Bacteriolysis↗