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Biomedical subjects

G F Brooks

Publications and source records attributed to G F Brooks.

At least 37 records · Page 2Linked to original sources

Experience with selective reporting of susceptibility to antimicrobial agents.

Experience with a system of selective and hierarchical reporting of susceptibility to antimicrobial agents in the hospital setting is described. In March 1985 and January 1987 the medical records of all patients with susceptibility test results were reviewed; there were a total of 488 susceptibility reports. Antimicrobial therapy was evaluated for appropriateness on the basis of the reported susceptibility test results. Susceptibility reports would not have affected the choice of antimicrobial agents in the majority of cases because patients had already been discharged, infection had not been documented, or appropriate therapy had already been started. In approximately 40% of cases in which susceptibility reports could have influenced prescribing, physicians chose appropriate initial therapy after susceptibility results became available. If only the instances in which susceptibility reports could have influenced prescribing are considered, then therapy was appropriately changed 12.5% of the time in March 1985 and 24.2% of the time in January 1987. Selective reporting of susceptibility to antimicrobial agents should be viewed as an adjunct to, not a substitute for, other interventions to promote appropriate prescribing in cases of infection.

Anti-Infective Agents↗

Evaluation of broth media for routine culture of cerebrospinal and joint fluid specimens.

Broth cultures of cerebrospinal and joint fluids are important components in the culture detection of meningitis and septic arthritis. The authors examined 121 strains of bacteria isolated from clinical specimens representing 13 species or groups that cause meningitis and arthritis for growth in supplemented Thioglycolate broth (THIO), Supplemented Peptone Broth (SPB), and minced beef heart (MBH) media each alone or with added IsoVitaleX. Both SPB and MBH with IsoVitaleX performed better as broth culture media than the media without IsoVitaleX or THIO with or without IsoVitaleX.

Arthritis, Infectious↗

Development of a tissue culture model for gonococcal invasion.

Neisseria gonorrhoeae invasion of the human endometrial cell line HecIB was monitored by electron microscopy. Within six hours postinfection, the gonococci have attached to the surface of some HecIB cells and are embraced by microvilli. Gonococci subsequently enter the HecIB cells in membrane bound vesicles but by eight hours, gonococci can be seen free in the cytoplasm. At twelve hours post-infection some HecIB cells are observed containing hundreds of internalized bacteria. At twenty-four hours gonococci appear in large clusters embedded in a matrix of cellular debris, which are possibly the remains of lysed infected cells. In contrast, N. lactamica is adherent to the monolayer but noninvasive.

Adenocarcinoma↗

Vancomycin-induced neutropenia complicating bone marrow recovery in a patient with leukemia. Case report and review of the literature.

Neutropenia associated with intravenous vancomycin therapy is reported in a patient with chronic myelogenous leukemia. The patient received 12 days of vancomycin therapy without incidence; however, a second course of vancomycin initiated on hospital day 14 produced severe neutropenia. This delayed onset is typical of vancomycin-induced neutropenia. The neutropenia reversed, without complications, as soon as the vancomycin was discontinued.

Adult↗

Bactericidal action of nafcillin, vancomycin, and three cephalosporins against nafcillin-susceptible and nafcillin-resistant coagulase-negative staphylococci.

Coagulase-negative staphylococci (S. epidermidis, 43 strains; S. warneri, 16 strains; S. haemolyticus, five strains; and others, four strains) were tested by the agar dilution method for nafcillin susceptibility: 53 were susceptible with a minimal inhibitory concentration (MIC) of less than or equal to 2 micrograms/ml; four were of indeterminate susceptibility, MIC = 4-16 micrograms/ml; and 11 were resistant, MIC greater than or equal to 32 micrograms/ml. The bactericidal activities from 0 to 24 hr for nafcillin, vancomycin, cephalothin, cefazolin, and cefamandole, each at 16 micrograms/ml in broth, were determined for all the isolates. The data indicate that a nafcillin agar dilution susceptibility test result of resistance does not consistently predict lack of killing activity by the cephalosporins. It is likely that each cephalosporin would have to be tested against individual coagulase-negative staphylococci in order to determine a suitable therapeutic or prophylactic cephalosporin, if a cephalosporin were to be used. Vancomycin was bactericidal for all the nafcillin-resistant coagulase-negative organisms tested.

Cefamandole↗

An unusual Neisseria isolated from conjunctival cultures in rural Egypt.

Seven isolates of an unusual Neisseria sp. were obtained from eye cultures of children in two rural Egyptian villages. These Neisseria utilized only glucose, they exhibited a positive reaction when tested with antisera to crude antigen from Neisseria meningitidis and N. gonorrhoeae, and they did not react with the fluorescent antibody tests for N. gonorrhoeae or with the monoclonal antibodies used to serotype gonococci. The Egyptian isolates had colony morphology more typical of meningococci than gonococci and showed opaque and transparent colony variants. On SDS-PAGE, the major outer-membrane proteins had different patterns than those noted for comparable proteins of meningococci and gonococci; heat-modifiable outer-membrane proteins were present. Four of the six isolates examined had cryptic plasmids of 2.8 megadaltons, which were slightly larger than the cryptic plasmid of N. gonorrhoeae. These plasmids were homologous to the gonococcal cryptic plasmid, but had different restriction enzyme fragment patterns. The DNA from the Egyptian isolates, like DNA from N. meningitidis but unlike DNA from N. gonorrhoeae, could be cut with the restriction enzyme HaeIII. The frequency of transformation into a temperature-sensitive mutant of N. gonorrhoeae was 0.2 for the Egyptian isolates and 0.1 for N. meningitidis, a frequency that was 5-10-fold lower than that for the N. gonorrhoeae control isolates. Whole-cell DNA from the Egyptian isolates showed 68%-73% homology with N. gonorrhoeae and 57%-63% with N. meningitidis. On the basis of our observations, the Egyptian isolates are distinct from N. meningitidis and may represent a variant of N. gonorrhoeae. We suggest that the isolates be called Neisseria gonorrhoeae ssp. kochii.

Bacterial Proteins↗

Effect of storage temperature and pH on the stability of antimicrobial agents in MIC trays.

Twelve antimicrobial agents, ampicillin, aztreonam, cefamandole, cefazolin, cefonicid, ceforanide, ceftazidime, ceftizoxime, ceftriaxone, cefuroxime, ciprofloxacin, and norfloxacin, were prepared at pH 6.80 and 7.31 in microdilution trays for storage at 4, -10, -25, and -70 degrees C and for weekly susceptibility testing. All 12 drugs had stable biological activity when stored at -70 degrees C for 1 year. All but ampicillin and aztreonam were stable at -25 degrees C. Storage at -10 degrees C was least satisfactory. Desiccation occurred at 4 degrees C, but short-term storage at this temperature is possible since the antimicrobial agents are stable for up to several months.

Anti-Bacterial Agents↗

Antibody-antigen specificity in the immune response to infection with Neisseria gonorrhoeae.

This study was done to define antigens important in the immune response to infection with Neisseria gonorrhoeae. Sera were obtained from men and women with uncomplicated gonorrhea (UGC), women with disseminated gonococcal infection, and women with gonococcal pelvic inflammatory disease (PID); sera were also obtained from uninfected controls. Vaginal fluids were taken from 15 patients with UCG or PID. The sera and vaginal fluids were tested against gonococcal isolates from the same patients to examine homologous antibody-antigen interactions by use of the western blot technique. Antibodies in the serum reacted with more gonococcal antigens compared with antibodies in the vaginal fluid. IgG in serum and vaginal fluid reacted with more antigens than did IgA in the same specimens. The predominant antigens reactive with IgG in serum were pili, protein II, a broad 23-33-kDa band of antigen, and presumptive lipopolysaccharide; and for IgA, protein II and a 46-48-kDa protein. The control sera also reacted with the 46-48-kDa protein. The predominant antigens reactive with IgG in vaginal fluid were protein I, protein II, pili, and the 46-48-kDa protein; and for IgA, protein I, protein II, and pili. Immunoglobulin in vaginal fluid reacted comparatively more with protein I than did immunoglobulin in serum.

Adolescent↗

Effects of storage temperature and pH on the stability of eleven beta-lactam antibiotics in MIC trays.

Microdilution MIC test trays containing 11 beta-lactam antibiotics in Mueller-Hinton broth at pH 7.31 or 6.80 were prepared and stored at 4, -10, -25, and -70 degrees C. The drugs tested were ampicillin, ticarcillin, mezlocillin, piperacillin, azlocillin, cefazolin, cefotaxime, moxalactam, cefoperazone, ceftriaxone, and imipenem. MICs for Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 were determined at weekly intervals for up to 1 year. The data from the MIC determinations showed the stability of antimicrobial activity over time to be -70 degrees C greater than -25 degrees C approximately 4 degrees C much greater than -10 degrees C. The relative stability at 4 degrees C as compared with that at -10 degrees C cannot be explained by desiccation, as determined by changes in broth sodium concentrations. The relative instability at -10 degrees C may have been caused in part by a temperature fluctuation, resulting in intermittent freezing and thawing of the antibiotics. Some of the drugs appeared to be more stable when diluted in broth at pH 6.80, but endpoints were more difficult to read. Cefazolin and cefoperazone were stable at all four storage temperatures. Cefotaxime, moxalactam, and ceftriaxone also were relatively stable. The other drugs showed moderately rapid to rapid deterioration at each temperature except -70 degrees C. Storage at -25 degrees C is suitable for up to 3 months for many, but not all, beta-lactams; -10 degrees C appears to be unsuitable. Storage at -70 degrees C is recommended.

Anti-Bacterial Agents↗

Inhibition of Neisseria gonorrhoeae attachment to HeLa cells with monoclonal antibody directed against a protein II.

This study showed that a protein II (PII) of Neisseria gonorrhoeae FA1090 appeared to act as a mediator of attachment to HeLa cells. Two colony variants of FA1090 were selected. Both gonococcal variants were nonpiliated, but one contained a PII and the other did not. A monoclonal antibody (1090-10.1), which was directed against the PII, inhibited the apparent PII-mediated attachment to HeLa cells. Antibodies produced from clone 1035-4, which had no PII specificity, did not inhibit the attachment and were used as controls. Inhibition of gonococcal attachment by the 1090-10.1 monoclonal antibodies was demonstrated by fluorescent microscopy analysis. Monoclonal antibody 1090-10.1 appeared to cause agglutination of the PII-containing organism. To block the clumping caused by the PII-specific monoclonal antibodies, Fab fragments of goat anti-mouse IgG were incubated with gonococci and the 1090-10.1 monoclonal antibodies. The results showed that the goat anti-mouse IgG Fab fragments partially blocked the agglutination caused by the PII-specific monoclonal antibody. The effect of the 1090-10.1 antibodies on attachment was also determined by monitoring the HeLa cells with attached iodinated gonococci. The monoclonal antibody appeared to inhibit the PII-mediated attachment.

Animals↗

Clinical use of the new beta-lactam antimicrobial drugs. Practical considerations for physicians, microbiology laboratories, pharmacists, and formulary committees.

New beta-lactam antimicrobial agents with extended antibacterial activity for gram-negative bacilli are being developed and marketed. These drugs provide major advances, especially for treatment of serious infections caused by multiresistant organisms. Several of the drugs have been marketed and many more will be available. Some of these drugs are considerably more costly than the older beta-lactams. The large number of new antimicrobial drugs coupled with their high costs pose complex problems for physicians, microbiology laboratories, and pharmacists. Community hospitals, large general hospitals, and tertiary care hospitals have different needs for patient care and will need different formats for unbiased education, susceptibility testing, pharmacy stocking, and controlling or monitoring for inappropriate use.

Anti-Bacterial Agents↗

Relation of protein I and colony opacity to serum killing of Neisseria gonorrhoeae.

Serum bactericidal tests were done for isogenic Neisseria gonorrhoeae that formed transparent or opaque colonies. Analysis of the data from individual strains showed that the molecular weight of protein I was a highly significant, but not universal, determinant of serum sensitivity or resistance. N. gonorrhoeae organisms with high-molecular-weight protein I were more serum-sensitive. Multivariate analysis of the data from 43 strains indicated that N. gonorrhoeae organisms from transparent colonies were more serum-resistant than isogenic organisms from opaque colonies (P = 0.01). Survivors of bactericidal reactions in which the initial inoculum was from opaque colonies tended to form transparent colonies. Bactericidal action by sera from men was highly associated (P less than 0.02) with the molecular weight of protein I and with the presence of protein II bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas bactericidal action by sera from women was associated only with the molecular weight of protein I.

Bacterial Outer Membrane Proteins↗

Human seminal plasma inhibition of antibody complement-mediated killing and opsonization of Neisseria gonorrhoeae and other gram-negative organisms.

Seminal plasma diluted 1:5-1:1,000 gave marked inhibition of serum antibody complement-mediated bactericidal and opsonic effects against Neisseria gonorrhoeae and other gram-negative organisms. Serum that was bactericidal at a dilution of 1:5,120 was not bactericidal at a dilution of 1:10 when seminal plasma was added. Bactericidal action of immune human or rabbit sera, or purified immunoglobulin (Ig)G or IgM plus complement for six strains of N. gonorrhoeae, serogroups A, B, C, and Y of Neisseria meningitidis, Escherichia coli and other gram-negative rods was inhibited by seminal plasma. Using C8- or C7-deficient sera as antibody and complement sources, opsonization, phagocytosis, and killing of N. gonorrhoeae and E. coli 014-K7 were inhibited by seminal plasma. Opsonization, phagocytosis, and killing of Staphylococcus aureus 502A was not inhibited. For the gram-negative organisms, the early phase of the opsonization process, probably complement activation, appeared to be inhibited rather than the ingestion or polymorphonuclear leukocyte killing steps; addition of seminal plasma yielded a significant reduction in the percentage of polymorphonuclear cells with associated bacteria. Seminal plasma did not prevent attachment of IgG, IgM, or IgA antibodies to gonococci. It reduced serum hemolytic whole complement activity by 25%. The seminal plasma inhibitor was of low molecular weight and was stable at 56 degrees C for 30 min, but inhibitory activity was lost after heating to 100 degrees C for 10 min. It is likely that the inhibitory factor(s) is a low-molecular weight protease or protease inhibitor. Seminal plasma probably has an important role in inhibition of complement and antibody functions in the genital tract. It may enhance pathogenesis of agents of sexually transmitted diseases.

Antibodies, Bacterial↗

Primary isolation of a new strain of the TATLOCK/Pittsburgh pneumonia agent (Legionella micdadei).

Pneumonia, empyema and lung abscesses developed in a patient following a neurosurgical procedure and associated short-term corticosteroid therapy. An organism identical to the TATLOCK/Pittsburgh pneumonia agent (Legionella micdadei) was the only organism isolated from multiple specimens from lung aspirates and chest tube drainage. The organism was isolated directly on charcoal yeast extract (CYE) agar and classified as identical to the TATLOCK bacterium by direct immunofluorescent staining and by gas-liquid chromatography of cellular fatty acids. The patient's pulmonary infection improved during treatment with penicillin. Serum specimens obtained from the patient during convalescence showed an indirect fluorescent antibody reciprocal titer of 16,000 to his homologous antigen, but he also had titers that were potentially diagnostic against antigens of the six serogroups of Legionella pneumophila and three other Legionella-like organisms. Legionella can be isolated from clinical specimens by the routine use of CYE agar, which should be incorporated as the primary isolation medium for chest fluids and lung specimens. It appears that a large battery of antigens will be required for serological testing to diagnose infections caused by L micadei, L pneumophila and Legionella-like organisms.

Empyema↗

Microbiology and pathogenesis of acute salpingitis as determined by laparoscopy: what is the appropriate site to sample?

Acute salpingitis is a polymicrobial disease. Neisseria gonorrhoeae and anaerobic gram-positive cocci were the predominant microorganisms isolated from the fallopian tubes of salpingitis patients. Gonococci were isolated from the fallopian tubes in eight of 35 (23%) patients; anaerobic bacteria were recovered from 10 of 35 (28.5%). Although Chlamydia trachomatis was not recovered from the fallopian tube exudate, there was abundant serologic evidence of chlamydial infection in the salpingitis patients. Twenty-three percent of patients with paired sera had a fourfold rise in IgM and IgG titer, which was consistent with systemic chlamydial infection. Comparison of cultures obtained via laparoscopy and culdocentesis suggested that culdocentesis is not an accurate reflection of the microbial milieu in the fallopian tube.

Ascitic Fluid↗