Biomedical subjects

B W Senior

Publications and source records attributed to B W Senior.

10 recordsLinked to original sources

PubMed1992

Proteinases of Proteus spp.: purification, properties, and detection in urine of infected patients.

The proteinases secreted by pathogenic strains of Proteus mirabilis, P. vulgaris biotype 2, P. vulgaris biotype 3, and P. penneri were purified with almost 100% recovery by affinity chromatography on phenyl-Sepharose followed by anion-exchange chromatography. The proteinase purified from the urinary tract pathogen P. mirabilis, which we had previously shown to degrade immunoglobulins A and G, appeared as a composite of a single band and a double band (53 and 50 kDa, respectively) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The other Proteus proteinases had similar patterns but slightly different mobilities. In each case all proteinase activity in culture supernatants was demonstrated by gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be associated with only the triple-band complex; all three bands were proteolytically active. The P. mirabilis proteinase was resistant to inhibitors of both serine and thiol proteinases but strongly inhibited by metal chelators, although it was not affected by phosphoramidon, an inhibitor of the thermolysin group of bacterial metalloproteinases. Active proteinase was detected in urine samples from P. mirabilis-infected patients; this is consistent with our detection of immunoglobulin A fragments of a size suggestive of P. mirabilis proteinase activity.

Chromatography, Affinity↗

PubMed1992

Use of telephone enquiries to a microbiology laboratory as a proxy measure of reporting efficiency.

AIMS: To assess the efficacy of a bacteriology service in respect of the time interval between collection of specimen and receipt of final report using the number and type of incoming telephone enquiries as a proxy measure. METHODS: For three months, all incoming telephone enquiries regarding the results of bacteriology specimens were monitored. Specimen type, date of sampling, the sender's location and the reason for making the telephone enquiry were recorded. RESULTS: The number of telephone enquiries made during the study was 1170, about 5% of the total number of samples received. Most enquiries related to results of urine cultures. These accounted for 33.9% of the calls, but only 5% of the total number of urines cultured. Enquiries relating to blood cultures were the next largest group accounting for 14.9% of calls, but 11% of the blood cultures received resulted in a telephone enquiry. The most frequent reason for making the telephone call was that the sender had not received the final report. CONCLUSIONS: Clinicians may have unrealistic expectations of the time taken to examine a specimen. A requirement for reporting sterile blood cultures after a shorter incubation period was found, and the value to patient management of earlier reporting of negative urine samples was identified.

Bacteriology↗

PubMed1991

Purification and characterization of human immunoglobulin IgA1 and IgA2 isotypes from serum.

A method is described for the simultaneous purification of IgA1 and IgA2 from human serum. Ammonium sulphate precipitation, gel filtration and ion-exchange chromatography on DEAE-Sephacel yielded a partially purified IgA preparation which was separated quantitatively into IgA1 and IgA2 by affinity chromatography on jacalin-Sepharose. The IgA1 which bound to the jacalin was eluted with 0.8 M D-galactose. The IgA1 preparation was apparently homogeneous by SDS-PAGE but contained a trace of C1-inhibitor and a second protein detected by immunoelectrophoresis. The IgA2 which did not bind to the jacalin was purified to apparent homogeneity by chromatography on columns of Protein G-Sepharose, Fastflow-S Sepharose and Superose 6. Typical yields were 95% and 58% for IgA1 and IgA2 respectively or 253 mg and 24 mg per 100 ml serum. The IgA1 and IgA2 were characterised by their reactivity with isotype specific monoclonal antibodies and sensitivity to bacterial proteinases. The IgA2 preparation apparently contained both allotypes, IgA2m(1) and IgA2m(2).

Chromatography, Gel↗

PubMed1991

The production and activity in vivo of Proteus mirabilis IgA protease in infections of the urinary tract.

Immunoblotting of urine from 21 patients of both sexes and of wide age range who had a Proteus mirabilis urinary tract infection (UTI) showed that 14 (64%) specimens contained immunoglobulin A (IgA). In nine (64%) of these the IgA heavy chain had been degraded to fragments of a size identical to those formed when purified IgA was degraded by pure P. mirabilis protease. Urine from patients with clinical evidence of upper UTI contained fragmented IgA and in some of these urine samples P. mirabilis protease activity was detectable. Urine infected with a non-proteolytic strain contained only intact IgA. It is concluded that P. mirabilis IgA protease is produced and is active during infections of the urinary tract.

Adolescent↗

PubMed1990

Protein profile typing--a new method of typing Morganella morganii strains.

A new, simple and stable method for typing Morganella morganii strains is described. The 150 strains examined, principally from faeces, contained haemolytic and non-haemolytic representatives of diverse O serogroup, bacteriocin type and biotype. Among the biotypes were some trehalose-fermenting, tetracycline-resistant strains and some non-motile, tetracycline-sensitive, glycerol fermenters. After analysis of cell lysates by sodium dodecyl sulphate-discontinuous polyacrylamide gel electrophoresis, strains could be differentiated into 21 types on the basis of outer membrane proteins (OMP) of 35-40 Kda. The OMP profile was not altered by culture on various common media and was unrelated to either O antigen or morganocin p-type. The finest strain recognition in M. morganii can be achieved by application of all three distinct typing methods.

Antigens, Bacterial↗

PubMed1990

New O antigens of Morganella morganii and the relationships between haemolysin production. O antigens and morganocin types of strains.

A collection of 142 strains of Morganella morganii, principally from unrelated patients' faeces was examined to determine the relationship, if any, between haemolysin production, O antigen and morganocin production/sensitivity type. Only 55 (38.7%) were agglutinable with the existing 44 O antisera. However, when O antisera were raised to some of the non-typable strains 11 new O antigens were found and 126 (88.7%) of the strains were typable. The number of O antigenic groups in M. morganii is now 55. It was confirmed that the O antigenic characteristics of strains were independent from morganocin producer types. An epidemiological retrospective survey showed that finer strain recognition in M. morganii can be achieved by using both methods than either method alone. Approximately 30% of strains were haemolytic. The ability to produce haemolysin was more common in strains of certain O serogroups and morganocin producer types than in others.

Antigens, Bacterial↗

PubMed1979

The special affinity of particular types of Proteus mirabilis for the urinary tract.

The strains of Proteus species found in significant numbers and as pure cultures in urine from 217 individuals were isolated, identified to species level and typed for proticine production (P type) and proticine sensitivity (S type) to give their P/S type. Urinary-tract infections with Proteus, principally P. mirabilis, were associated with the elderly. Ninety seven distinct P/S types were found but three P/S types P3/S1,8, P3/S1,8,13 and P3/S1,13 were isolated at a much higher frequency (14%) then could be explained from their faecal carriage rate. These types were almost without exception restricted to patients with clinical symptoms of urinary-tract infection and it is suggested therefore that they have some special affinity for the urinary tract.

Adolescent↗

PubMed1978

p-nitrophenylglycerol--a superior antiswarming agent for isolating and identifying pathogens from clinical material.

The antiswarming agent p-nitrophenylglycerol (PNPG) has been found invaluable for the recognition and isolation of pathogenic bacteria from specimens contaminated with swarming strains of Proteus spp. PNPG is cheap, stable and non-toxic. All strains tested grew well in its presence and produced characteristic morphology. PNPG was without effect on the results of a variety of identification tests performed directly on colonies from media containing PNPG. This permitted identification without the need for further subculture.

Bacteria↗

PubMed1977

The Dienes phenomenon: identification of the determinants of compatibility.

Two hundred and four isolates of swarming strains of Proteus species which had been typed for their ability to produce bacteriocin (proticine) and also their proticine sensitivity (P/S typing) were tested in all combinations for their Dienes compatibility with each other. Ninety-eight distinct Dienes compatibility groups were found. Physiological and genetic experiments supported the evidence of typing results that, irrespective of species, both the type of proticine a strain produces (P type) and the sensitivity of the strain to proticine (S type) were determinants of Dienes compatibility. Strains showing compatibility in the Dienes test were of the same P/S type, whereas those of different P/S types were incompatible.

Bacteriocins↗

PubMed1977

Typing of Proteus strains by proticine production and sensitivity.

A simple, reliable and highly discriminating scheme for the bacteriocine typing of Proteus has been developed. Strains are typed on MacConkey's agar according to their ability to produce a proticine active against one of 14 indicator strains having a single and specific proticine sensitivity and also according to their sensitivity to the different proticines of 13 proticine-producing strains. This new scheme of combined production and sensitivity typing was formulated after 250 strains of Proteus from clinical material had been examined for the production of proticines active against the 24 indicator strains of Cradock-Watson's proticine typing scheme and for proticine activity and sensitivity towards each other. Three new types of proticinogenic strains were discovered and defined. Strains producing proticines of types 1, 2 and 3 were isolated frequently. These common proticines could be subtyped by their different actions on newly characterised indicator strains. By means of this production/sensitivity (P/S) typing scheme, 250 Proteus strains were differentiated into 90 distinct types, whereas typing by sensitivity alone distinguished only 40 types and typing by production alone distinguished only 20 types (including subtypes).

Bacteriocins↗