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Biomedical subjects

B M Gray

Publications and source records attributed to B M Gray.

80 records · Page 5Linked to original sources

Susceptibility of Staphylococcus aureus to cefaclor and cephalothin: laboratory and clinical studies.

In vitro susceptibility tests of 201 strains of Staphylococcus aureus by agar dilution revealed 90% to be susceptible to 8 mug or less of cefaclor per ml. Strains from hospitalized children and adults were more often resistant than those from patients with bullous impetigo. Cephalothin was more active than cefaclor against all strains tested. Results with disk tests, including those strains examined from the clinical investigation, revealed some discrepancies in identifying strains more resistant to cefaclor. In clinical studies, cefaclor proved quite effective for the treatment of bullous impetigo. Of 73 patients, 90% were cured and 7% improved after completing 5 or more days of treatment. Prompt improvement was noted among most patients seen 3 to 5 days after treatment was begun. One patient experienced mild diarrhea. There were no other adverse or toxic manifestations attributable to therapy.

Adolescent↗

Manner and meaning of susceptibility testing of ampicillin-resistant Haemophilus influenzae.

We examined ampicillin-resistant strains of Haemophilus influenzae to compare the percentage of resistant organisms in each strain with the susceptibility to ampicillin by an agar dilution method. Using an inoculum of 10(4) colony-forming units, the minimal inhibitory concentration (MIC) increased with the percentage of resistant organisms in the strain. Laboratory-manipulated strains composed of different proportions of a susceptible and a resistant strain behaved similarly. The survival of isolated colony-forming units (colony MIC) was then determined by spreading inocula over the surface of a set of MIC plates, resulting in separation of individual colonies. This modification of the susceptibility test to the colony level gave end points that were clear and reproducible and that did not vary with changes in incubation time or temperature. True differences in susceptibility among strains were demonstrated by this method, whereas results of the conventional MIC test may reflect only the number of resistant organisms present in the inoculum.

Ampicillin↗

Immunochemical characterization of the polysaccharide antigens of group B streptococci.

Mouse monoclonal antibodies were used in the immunochemical characterization of the polysaccharide antigens of group B streptococci (GBS). Monoclonal antibodies specific for the sialylated form of the GBS type III polysaccharide were highly protective in a mouse model of GBS type III infection, whether of IgM, IgG2a, or IgA isotypes, but monoclonal antibodies specific for the nonsialylated form of the type III antigen were not protective, regardless of isotype. Monoclonal antibodies reacting with the type II polysaccharide antigen could be divided into two general antigen binding groups on the basis of the ability of beta-methylgalactopyranoside to inhibit their binding to purified type II antigen. Various proportions of antibodies with the two specificities were observed in rabbit and human sera. Although it was previously reported that rabbit antisera could not distinguish between the sialylated and nonsialylated forms of the type Ib polysaccharide, mouse monoclonal antibodies were found to exhibit exclusive specificity for one or the other form of the antigen. Only monoclonal antibodies specific for the sialylated Ib polysaccharide were protective in a mouse model.

Animals↗

Clinical and epidemiologic studies of pneumococcal infection in children.

Streptococcus pneumoniae was isolated from 1310 children in a 5-year period from 1979 through 1984. There were 44 cases of meningitis, 172 bacteremic infections, 787 cases of otitis media and 307 respiratory and miscellaneous isolates. The majority of infections could be accounted for by a small number of serotypes, with types 3, 6, 14, 19 and 23 predominating. Most infections (70%) occurred in infants younger than 2 years of age. However, nearly one-fourth of those suffering systemic illness had some underlying condition which may have contributed to their risk for infection, even beyond 2 years of age. Ten of the 12 deaths occurred in patients with altered host defenses. Characteristics of pneumococcal disease and the distribution of serotypes are discussed in relation to the work of other investigators over the past 50 years.

Age Factors↗