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Biomedical subjects

Y Holloway

Publications and source records attributed to Y Holloway.

33 records · Page 2Linked to original sources
PubMed1983

Penicillin prophylaxis in children with cardiac disease: postextraction bacteremia and penicillin-resistant strains of viridans streptococci.

The incidence of postextraction bacteremia in 82 children with dental foci and cardiac disease given parenteral penicillin prophylaxis was assessed 5 min after extraction. Penicillin concentrations were determined in blood samples obtained at the same time. Before extraction, cultures were taken from the gingival sulcus. Postextraction bacteremia occurred in 21% of the patients and was due to penicillin-sensitive microorganisms in 10 and to both penicillin-sensitive and penicillin-resistant microorganisms in seven children. In three of these children penicillin-resistant viridans streptococcal strains were isolated. Penicillin-resistant viridans streptococci were present in the gingival sulcus flora of 39% of the children, but a relationship between the presence of such strains in the gingival sulcus and the occurrence of postextraction bacteremia could not be demonstrated. There was no difference in the serum penicillin concentrations found in children with bacteremia due to penicillin-sensitive or penicillin-resistant microorganisms, or between the concentrations in children with and without bacteremia.

Adolescent↗
PubMed1983

Importance of minimizing carry-over effect at subculture in the detection of penicillin-tolerant viridans group streptococci.

Penicillin susceptibility determinations made for 14 strains of Streptococcus mitior by two different broth dilution tests revealed small numbers of tolerant strains regardless of the volumes (0.01 and 0.1 ml) of subcultured broth. The addition of penicillinase to the subculture medium increased the number of tolerant strains significantly in 0.1 ml of subcultured broth, demonstrating that the detection of penicillin-tolerant viridans group streptococci might be hampered by the carry-over of penicillin.

Microbial Sensitivity Tests↗
PubMed1983

Incidence of postextraction bacteremia under penicillin cover in children with cardiac disease.

To assess the efficacy of penicillin prophylaxis as recommended by the American Heart Association to prevent the onset of bacterial endocarditis, the incidence of postextraction bacteremia was determined in 82 children with cardiac disease who were receiving prophylactic penicillin. Aerobic and anaerobic blood cultures were taken five minutes after dental extraction, as was a blood sample to assay the serum penicillin concentration. The incidence of postextraction bacteremia was 21%. Streptococcal species accounted for half of the number of aerobes isolated. Of the isolated microorganisms, 16% were strict anaerobes. Susceptibility testing of the isolates showed that 24 penicillin-sensitive and eight penicillin-resistant microorganisms caused the bacteremia. There was neither a significant difference between the serum penicillin concentrations of children with and without bacteremia, nor between the serum penicillin concentrations of children with bacteremia due to penicillin-sensitive microorganisms and children with bacteremia due to penicillin-resistant microorganisms. It is concluded that the occurrence of postextraction bacteremia is not prevented by penicillin prophylaxis and that the serum penicillin concentration at extraction is not the discriminating factor in preventing this bacteremia. None of the children developed bacterial endocarditis. It is speculated that mechanisms not thoroughly studied are involved in the prevention of bacterial endocarditis after dental extraction.

Adolescent↗
PubMed1982

Penicillin tolerance in nutritionally variant streptococci.

Eleven strains of nutritionally variant streptococci were tested for their susceptibility to penicillin by a broth dilution method. All minimal inhibitory concentrations were low. It was found that plates containing only vitamin B6 (pyridoxal HCl) and cysteine did not reveal true minimal bactericidal concentrations. When penicillinase was added to the subculture medium and a staphylococcal streak was made across the plates, all 11 strains were found to have high minimal bactericidal concentrations and were shown to be tolerant to penicillin.

Culture Media↗
PubMed1982

Screening for penicillin tolerance in viridans streptococci by a simple disk method.

A disk method was developed for demonstrating penicillin tolerance in viridans streptococci. This was achieved by the substitution of the penicillin disk used for susceptibility testing by a disk containing penicillinase. After reincubation, penicillin-tolerant strains exhibited new growth in the area adjacent to this disk, providing a rapid screening test.

Drug Tolerance↗
PubMed1981

Comparative clinical evaluation of the effect of sucrose in a new anaerobic blood culture medium.

In order to study the effect of excess sucrose on microorganisms, growth curves of 5 anaerobic and 5 aerobic microorganisms were performed in Diagnostic Anaerobic Growth (DAG) medium, and in a variant of DAG supplemented with 200 g/l sucrose (DAG-S). It was found that both aerobes and anaerobes were suppressed by the additional sucrose. In a clinical trial 1,800 blood cultures froms 1,332 patients were simultaneously inoculated into DAG and DAG-S. Results showed that excess sucrose did not improve the yield of anaerobic or aerobic microorganisms and rather tended to inhibit their growth. The only microorganisms which possibly benefitted from DAG-S were some Enterobacteriaceae species.

Bacteria↗
PubMed1980

A new anaerobic blood culture medium: laboratory evaluation.

A new medium, Diagnostic Anaerobic Growth Medium (DAG) was evolved for the culture of anaerobic bacteria from blood. Redox potential measurements of DAG, in comparison with four other commonly used media (supplemented peptone broth; thioglycollate broth; chopped meat glucose broth; tryptone soya broth) showed that Ecal of DAG medium to be lower than that of the other media tested. The new medium recovered more quickly after addition of blood, to reach "blank" values within 4 h. Growth curves of 21 anaerobic bacteria in DAG medium showed that they all multiplied satisfactorily.

Anaerobiosis↗
PubMed1979

Identification of viridans streptococci on the Minitek Miniaturised Differentiation System.

A total of 227 strains of viridans streptococci were simultaneously identified on the Minitek Miniaturised System (BBL) and by a conventional method according to Colman and Williams. The Minitek discs were each overlaid with a drop of sterile liquid paraffin, and the trays were incubated in GaSPak jars (BBL) with CO2 generator envelopes. Identification was possible three to four days earlier than with the conventional method. The results were found to be in agreement with the conventional method. Compared to the identification schemes of Cowan and Steel and of Facklam, the results were also in good agreement. Minor differences were found in the number of positive and negative results in those reactions that are variable in all three schemes.

Methods↗
PubMed1979

Identification of anaerobes on the Minitek System, compared to a conventional system.

The Minitek Miniaturized System (BBL) was compared to a conventional method (V.P.I.) for the indentification of anaerobes. Anaerobiosis was achieved by using the GasPak system (BBL) and a glove box. Gram staining, colonial morphology, gas-liquid chromatography and biochemical reactions as detailed in the Virginia Polytechnic Institute anaerobe laboratory manual were compared to the biochemical results obtained on the Minitek system. A total of 32 anaerobes was used. The percentage of correlation was an overall 98.2%. Discrepancies were found mostly in the production of indole, the reduction of nitrate, and the hydrolysis of aesculin. A further 95 anaerobes were tested on these three reactions, and found to give an overall agreement of 92.9%. It was found necessary to use some additional tests as well as gas-liquid chromatography for definitive identification. The microsystem was also evaluated as to time saved, cost and ease of use.

Anaerobiosis↗
PubMed1977

The effect of amniotic fluid on bacterial growth in three population groups.

Eighty-five amniotic fluid from women of three racial groups in the third trimester of pregnancy were each tested for antibacterial activity against Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Streptococcus faecalis, and Candida albicans. Seventy-six per cent of fluid samples from white patients were inhibitory, while the corresponding figures for Africans and Indians were 33 and 52, respectively. Of 19 African fluid samples tested against E. coli only, one proved inhibitory.

Amniotic Fluid↗
PubMed1976

Anaerobic infections in hospital practice.

The role of anaerobes in the pathogenesis of infections was investigated. Anaerobes were isolated from 0,25% of blood cultures and from 15,8% of other specimens tested; in 15,1% of cases where anaerobes were isolated, no aerobes were found. The strains most commonly encountered were Bacteroides fragilis, B. melaninogenicus, Peptostreptococcus anaerobius and Clostridium perfringens. Sensitivity tests in vitro showed all organisms to be sensitive to clindamycin, metronidazole and chloramphenicol, while a large proportion were resistant to penicillin G and smaller numbers were resistant to tetracycline.

Anaerobiosis↗