Search PubMed⌕ Search

Biomedical subjects

J G Barr

Publications and source records attributed to J G Barr.

At least 37 records · Page 2Linked to original sources
PubMed1987

Correlation between antibiotic sensitivity testing by conventional and conductivity measurements.

A high correlation in the susceptibilities of 44 strains isolated from clinical material to a variety of antimicrobial agents was found between the minimum inhibitory concentration and conductivity measurements. Some discrepancy was found for vancomycin and teicoplanin when tested against 21 strains of staphylococci. Similarly, discrepancies were seen with azlocillin, chloramphenicol and gentamicin when tested against strains of aerobic and facultatively anaerobic Gram-negative bacilli. In the majority of cases in which discrepancies were noted, this reflected differences in relative, and not absolute, susceptibility. With five strains of Pseudomonas, however, there was a poor correlation with three of four antibiotics studied. The advantage of this technique is that sensitivities are available within 4-6 h.

Anti-Bacterial Agents↗
PubMed1987

Value of charcoal media for recovering staphylococci incorporated in mupirocin ointment.

The use of charcoal blood agar supported a good recovery of staphylococci incorporated in Mupirocin ointment in a test in vitro system. The efficacy of this medium was particularly emphasised in the recovery of staphylococci damaged by six hours' exposure to Mupirocin. The media will be of value in following the progress of staphylococcal carriage or infection in patients or carriers being treated with topical Mupirocin.

Anti-Bacterial Agents↗
PubMed1985

Microaerophilic/anaerobic bacteria as a cause of urinary tract infection in pregnancy.

The involvement of microaerophilic/anaerobic bacteria as a cause of urinary tract infection was investigated by appropriate culture of urine samples obtained after periurethral toilet from 48 pregnant women admitted to hospital with urinary tract symptoms. Significant bacterial counts were demonstrated in 28 of these patients; 24 were due to microaerophilic/anaerobic organisms, and the remaining four were due to established urinary pathogens. In 25 pregnant women admitted without urinary tract symptoms, who were used as controls, four had significant bacterial counts, all of which were due to microaerophilic/anaerobic organisms. It is concluded that these organisms may be responsible for urinary tract symptoms in pregnant women when no significant growth is demonstrated on urinary culture by conventional methods.

Bacteriuria↗
PubMed1985

An automated blood culture system: the detection of anaerobic bacteria using a Malthus Microbiological Growth Analyser.

The Malthus Microbiological Growth Analyser has proved to be sensitive in detecting conductivity changes due to anaerobic metabolism in a number of widely used blood culture media. Freshly prepared cooked meat media and Thiol medium yielded the greatest gross conductivity changes, and were more sensitive of anaerobic metabolism than other media. Failure of the instrument to detect anaerobic metabolism was a problem particularly associated with growth in the thioglycollate medium. False positive detections of growth were attributed to a number of factors including electrode instability (6.0%) and bacterial contamination (8.75%).

Bacteria, Anaerobic↗
PubMed1981

Spontaneous loss and transfer of plasmid-mediated K21 antigen synthesis in Klebsiella pneumoniae.

Five epidemiologically related urine isolates of Klebsiella pneumoniae (sensu lato), capsular serotype K21 may spontaneously lose the ability to synthesise K21 antigen in vitro and in vivo. Another four isolates of K. pneumoniae K21+, epidemiologically unrelated to the other five, did not exhibit this effect. Elimination of the ability to synthesise K21 antigen may be enhanced by treatment with acridine orange. Transfer of K21 antigen synthesis from K. pneumoniae to Escherichia coli K12 was observed in eight independent experiments. Elimination from or acquisition of the ability to synthesise K21 antigen is not accompanied by changes in the antibiotic sensitivity patterns or biochemical characteristics of bacteria.

Acridine Orange↗
PubMed1981

Effect of prostaglandin synthesis inhibitors on clonidine-induced diuresis in rats.

Clonidine is a centrally acting antihypertensive drug that also has marked renal effects. The role of renal prostaglandins in clonidine-induced diuresis was examined in anesthetized and conscious rats. Twelve surgically prepared rats were pretreated with either of two inhibitors of prostaglandin synthesis, indomethacin or meclofenamate (2 mg/kg), while thirteen rats served as controls. Clonidine (200 micrograms/kg/hr, i. v.) increased urine flow tenfold in both pretreated and nonpretreated controls whereas blood pressure and glomerular filtration rate were reduced by clonidine. Fractional excretions of sodium, potassium, total solute and water were enhanced similarly in these two groups of anesthetized rats. Experiments were also conducted in ten conscious rats pretreated with vehicle, indomethacin (2.0 and 7.5 mg/kg), or meclofenamate (2 mg/kg) prior to clonidine infusion. Marked diuresis occurred whether these rats were pretreated with vehicle or one of the nonsteroidal antiinflammatory drugs (NSAID). Thus, NSAID did not prevent the renal excretory response to clonidine in either anesthetized or conscious rats, suggesting that enhanced prostaglandin synthesis is not an essential component of the diuretic action of this drug in rats.

Anesthesia↗
PubMed1980

Effect of the converting enzyme inhibitor SQ-20881 on urinary excretion of prostaglandin E2 in the rat: influence of pretreatment with deoxycorticosterone.

The effect of SQ-20881, an inhibitor of the peptidyl dipeptidase that degrades kinins and converts angiotensin I to angiotensin II, on the urinary excretion of immunoreactive prostaglandin E2 (iPGE2) was studied in rats receiving either deoxycorticosterone (DOCA, 5 mg/day s.c.) or sesame oil vehicle for 10 days before and then during the study, DOCA-treated animals had higher urinary excretion of iPHE2 and kallikrein, and lower plasma renin, than did animals injected with oil only. In rats pretreated with DOCA, infusion of SQ-20881 (1.2 mg/day s.c.) for 6 days increased iPGE2 excretion from 87.3 +/- 1.9 to 150.9 +/- 14.5 ng/day (P < .05). In contrast, in rats pretreated with vehicle, SQ-20881 had no significant effect on urine iPGE2. The enzyme inhibitor did not affect the intake of fluid, the volume of urine or the urinary excretion of kallikrein and electrolytes in either DOCA- or vehicle-treated animals. The blood pressure reduction elicited by a bolus injection of bradykinin (1.0 microgram i.v.) was greater in rats receiving SQ-20881 than in vehicle-infused controls, both in the DOCA- and in the sesame oil-treated groups, suggesting inhibition of kinin degradation by the converting enzyme inhibitor. These results indicate that DOCA or the consequences of its administration are required for SQ-20881 to increase iPHE2 excretion in the rat. Such an effect of the inhibitor probably relates to stimulation of renal prostaglandin synthesis consequent to elevation of kinin levels.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1979

Biotypes of Klebsiella pneumoniae (sensu lato) and Enterobacter aerogenes characterised by differential substrate metabolism: application of the technique.

A biochemical typing method is described for Klebsiella pneumoniae (sensu lato) and Enterobacter aerogenes. The technique depends on differences in metabolism of five carbon substrates--glycerol, inositol, lactose, glucose, and xylose--at two concentrations. Reproducibility is satisfactory and is monitored by the incorporation of control klebsiellae of known biotype. The method has been used for 12 months in the surveillance of urinary tract colonisation in this hospital. Gut carriage of klebsiellae, implicated by several workers as a source of infection, was common among staff and new admissions. Many biotypes were represented which were sensitive to most antibiotic except ampicillin. Klebsiellae, all multiply resistant, were isolated most frequently from urine specimens in two orthopaedic wards. In a longitudinal study in these wards, a sequential dominance in urinary tract colonisation by two klebsiella biotypes was shown, which suggested the presence of cross infection or an environmental reservoir. Confirmatory evidence was obtained from capsular serotypes and R-factor studies.

Bacteriological Techniques↗
PubMed1978

Variation in metabolism of biochemical test substrates by Klebsiella species: an epidemiological tool.

The variation in metabolism of biochemical test substrates by klebsiella isolates has been demonstrated. It is suggested that this variation is likely to result in false-negative reactions in biochemical tests incubated for short periods. The observations made may explain the reported difficulties in obtaining reproducible results in biotyping Klebsiella strains. Preliminary work suggests that differences in substrate metabolism will provide a means of increasing the sensitivity of methods for the biochemical typing of Klebsiella spp.

Bacteriological Techniques↗
PubMed1977

Klebsiella: taxonomy, nomenclature, and communication.

Differences in the delineation of Klebsiella spp. in the United Kingdom from that in the majority of other countries is discussed. An attempt is made to trace and interpret the reasons for these differences and suggestions are made for a rapid resolution of this problem which hazards communication.

Klebsiella↗