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Biomedical subjects

S Hafiz

Publications and source records attributed to S Hafiz.

At least 91 records · Page 5Linked to original sources
PubMed1982

Pathogenic microbial flora of genital ulcers in Sheffield with particular reference to herpes simplex virus and Haemophilus ducreyi.

The pathogenic microbial flora of genital ulcers in 161 (80 men and 81 women) unselected patients was studied prospectively. In only one case was Treponema pallidum responsible whereas herpes simplex virus was considered to be the cause of 130 (80.8%) genital ulcers. H ducreyi was isolated from 46 (28.6%) patients, most commonly as a secondary pathogen in herpetic lesions. Two or more pathogens were isolated from the ulcers in 67 (41.6%) patients, and in 21 (13%) patients no pathogens were isolated. Our results indicate an urgent need for antiviral treatment to reduce the local reservoir of genital herpes, challenge traditional concepts about the prevalence of H ducreyi in Britain, and call for a reappraisal of its role in the causation of genital ulcers.

Bacteria↗
PubMed1981

Transferable plasmid-mediated antibiotic resistance in Bacteroides.

Plasmid-mediated resistance to chloramphenicol (Chlr), erythromycin (Eryr), tetracycline (Tetr) and clindamycin (Clindr) was transferred from three clinical isolates of Bacteroides fragilis and one faecal isolate of B. thetaiotaomicron to strains of B. fragilis, B. distasonis and Escherichia coli, and subsequently to B. fragilis and E. coli second-and third-stage recipients in series. Successful transfer was achieved by membrane-filter and centrifugation techniques that provide stable cell-to-cell contact but not by simple mixed broth culture. Chlr Eryr Tetr and Clindr Eryr were transferred at high frequency (1.9 x 10(-3)-1.8 x 10(-4)) but Tetr was transferred at low frequencies (1-1.6 x 10(-6)). Segregation of resistance markers was observed with selection for Tetr when donors were Chlr Eryr Tetr and Chlr Tetr. All transcipients were identical with the parent recipient strains but had the resistance markers of the donor strains. Resistance to antibiotics other than tetracycline was cured by growth with subinhibitory concentrations of aminoacridines and ethidium bromide for 24 h; cure of solitary Tetr required longer incubation (21 days). Identical plasmid DNA bands were demonstrated by agarose-gel electrophoresis in all the donor and corresponding transcipient strains but plasmids were not found in the recipient strains or in strains cured of resistance. Plasmid-mediated transferable antiobiotic resistance in Bacteroides spp. may compromise the treatment of infections and may provide a reservoir of antibiotic resistance in the intestinal flora.

Anti-Bacterial Agents↗
PubMed1981

Chancroid in Sheffield. A report of 22 cases diagnosed by isolating Haemophilus ducreyi in a modified medium.

The causative organism of chancroid, Haemophilus ducreyi, is generally considered to be very fastidious and its isolation, maintenance, and detailed study very demanding. In this study a modified medium was developed, which allowed the organism to be isolated more frequently than previously would have been expected. Twenty-two cases of chancroid were confirmed by the isolation of H ducreyi in 160 patients with genital ulceration examined over a one-year period. The cases were apparently unrelated, and in only five was there a history of recent sexual contact abroad. Concurrent infection with other sexually transmitted diseases was present in 18 (81.8%) patients, and in 14 (63.6%) both H ducreyi and herpes simplex virus were isolated form the same genital ulcers. Thus, these findings indicate that chancroid is underdiagnosed in England and that H ducreyi may frequently occur as a secondary invader of damaged genital skin and mucosa.

Adolescent↗
PubMed1980

Induction of a cell wall variant of the gonococcus by human amylase.

Human amylase has been shown to be an effective and powerful inhibitor of the gonococcus in vitro. Its action appears to be on the bacterial cell wall. When tested in osmotically stabilised liquid media the organism was not inhibited; however the organisms which grew in such cultures appeared to be cell wall variants, which were less sensitive to penicillin than the parent strains. Studies on these variants suggest that they are "transitional-phase variants." Since cervical mucus has much in common with an alkaline osmotically stabilised liquid medium and also contains a high concentration of amylase, it seems possible that these variants may occur in vivo.

Amylases↗
PubMed1979

Inhibition of Neisseria gonorrhoeae by normal human saliva.

Saliva was found to be a powerful and specific inhibitor of Neisseria gonorrhoeae. Although 28 other species of bacteria were tested, including Neisseria meningitidis, Neisseria pharyngis var flava, Neisseria lactamica, and Neisseria catarrhalis, we failed to find any others sensitive to saliva under similar conditions. The physical properties of the inhibitory substance indicated that it might be salivary alpha-amylase. To test this hypothesis alpha-amylase was extracted from saliva and was shown to have a high antigonococcal activity. Hog pancreas alpha-amylase also showed strong antigonococcal activity, thus the observations indicate that for the strains we tested alpha-amylase is inhibitory to gonococci. This observation indicates that either the gonococcal outer cell wall contains some unique lipopolysaccharides or that the gonococcus is unusually dependent on the integrity of these moieties. Whichever speculation proves to be true it indicates a need for a careful study of the gonococcal cell wall.

Adult↗
PubMed1978

A simple manganous chloride and Congo red disc method for differentiating Neisseria gonorrhoeae from Neisseria meningitidis.

Manganous chloride and Congo red incorporated into blotting paper discs have been used to differentiate gonococci from meningococci. The new technique is simple and reliable; the materials for the test are inexpensive. The method will increase the efficiency of distinguishing between the pathogenic Neisseria in any clinical bacteriology laboratory and especially in those in the tropical areas.

Bacteriological Techniques↗
PubMed1978

Effects of various divalent cations on the survival of Neisseria gonorrhoeae in liquid media.

The effect of various concentrations of divalent cations on survival of gonococci in liquid medium was studied. The growth of Neisseria gonorrhoeae was inhibited by manganous chloride in concentrations above 1 X 10(-5)mol/l while the growth of control organisms such as Neisseria meningitidis and Escherichia coli was not inhibited by the same salt even at 1 X 10(-2)mol/l. Copper sulphate, cobaltous nitrate, nickel chloride, and zinc sulphate also had deleterious effects on gonococci. Magnesium chloride at 1.5 X 10(-1)mol/l permitted the growth of gonococci. The toxicity of manganous chloride and copper sulphate in the liquid media was in some measure reduced by adding charcoal but not by adding starch. The significance of these findings is discussed in relation to the efficiency of primary isolation and transport media for gonococci.

Cobalt↗
PubMed1978

Identification of Neisseria gonorrhoeae by carbohydrate disc reactions on a modified fermentation medium.

The identification of Neisseria gonorrhoeae by the use of a carbohydrate disc reaction on a modified fermentation medium is described. 70 out of the 71 strains tested produced detectable acid in 18--24 hours from the dextrose disc and no acid from Maltose, sucrose or lactose discs. One strain required 48 hours for good growth and acid production from dextrose disc only. The carbohydrate disc method was compared with a standard fermentation method using sugars incorporated in serum-free medium, 64 out of 71 strains of gonococci tested were identified after 18--24 hours incubation. All the strains gave clear-cut confirmatory results after 48 hours incubation. The importance of serum-free fermentation media in the identification of gonococci in tropical areas where meningococcal infections are also prevalent is discussed.

Bacteriological Techniques↗
PubMed1977

The survival of gonococci and meningococci in subcutaneous diffusion chambers in mice.

Studies are reported on the survival of gonococci and meningococci in Millipore diffusion chambers implanted subcutaneously in normal mice and in pre-immunised mice. The chambers allowed the passage of nutrients and humoral factors but excluded host cells. After an initial fall in the viable count--attributed to lysis by non-specific serum factors--there was evidence of multiplication of Neisseria gonorrhoeae; the subsequent development of specific antibody led to the disappearance of gonococci 16 days after the chambers were implanted. N. meningitidis behaved differently in the implanted chambers. Meningococci did not appear to be lysed by non-specific humoral factors and so the viable count showed no initial fall. The meningococci survived for 49 days, at which time the entire chamber was rejected.

Animals↗
PubMed1977

Reversion of Kellogg's colonial types of Neisseria gonorrhoeae in liquid medium.

Colonial type variation of gonococci is well known, but change from type 4 to type 4 to type 1 is rare except in vivo. By observing quantitatively subcultures from a new liquid medium it was possible to follow the day-to-day changes in the ratio of colonial types present. The results obtained showed that type 1 colonies could be derived from type 5 inocula even in unsupplemented media. In unsupplemented liquid medium, type 4 inocula did not revert to other types and indeed colonial type 4 appeared to be the final form of the organism before it died out. If, however, iron in the form of ferric citrate was added to the medium, reversion occurred and type 1 colonies rapidly came to predominate.

Culture Media↗
PubMed1976

Clostridium difficile: isolation and characteristics.

Clostridium difficile can be grown readily in Reinforced Clostridial Medium (RCM) containing 0-1-0-4% of o-, m- or p-cresol, or phenol. We recommend 0-2% of phenol or p-cresol in RCM for the isolation of this organism. The characteristic "cornfield" growth in RCM in 25-ml Universal containers is described. Glucose, fructose, galactose, mannose, raffinose, aesculin and mannitol are fermented with production of acid and gas; maltose, sucrose, glycogen, soluble starch and sorbitol are fermented with production of acid only. Lactose and rice starch are not fermented by any strain, and DL-methionine is not attacked. Nitrate is reduced to nitrite. Hydrogen sulphide and indole are not produced. Gelatin is attacked by all strains, but in some cases prolonged incubation is required. Hyaluronidase is produced, but not deoxyribonuclease. A lethal toxin appears to be produced. Strains possess shared and strain-specific antigens.

Anaerobiosis↗