PubMed Health⌕ Search

Biomedical subjects

I O Stewart

Publications and source records attributed to I O Stewart.

9 recordsLinked to original sources
PubMed1986

Detection of Chlamydia trachomatis antigens by enzyme immunoassay and immunofluorescence in genital specimens from symptomatic and asymptomatic men and women.

Chlamydia trachomatis antigens were detected in populations with the following infection prevalences: 26.5% (36 of 136) of men and 27.7% (48 of 173) of women attending a sexually transmitted disease clinic, 16.3% (53 of 324) of women attending a Planned Parenthood clinic, and 3.4% (4 of 117) of an obstetrics and gynecologic practice. Compared with cell culture of the combined female cervical specimens (15.8% prevalence), the respective sensitivities of Chlamydiazyme (Abbott Laboratories, North Chicago, Illinois) and Microtrak (Syva, Palo Alto, California) were 98.3% and 87.9%, specificities were 97.5% and 98.4%, positive predictive values were 87.7% and 92.7%, and negative predictive values were 99.7% and 97.5%. Both assays were 70.0% sensitive with male urethral specimens, and the other parameters of performance ranged between 84.0% and 97.2%. The antigen detection assays, compared with culture, performed equally well in subjects without or with clinical signs.

Adult↗
PubMed1980

Thrombocytopenia in septicemia: the role of disseminated intravascular coagulation.

The mechanism of isolated thrombocytopenia in septicemia is unknown, but compensated disseminated intravascular coagulation (DIC) has been suggested as a possible cause. To investigate this possibility, platelet counts and sensitive assays for in vivo thrombin and plasmin generation, including fibrinogen gel chromatography and fibrinopeptide A (FPA) assays, were obtained on 31 septicemic patients. Fifteen of 17 patients with gram-negative septicemia and 8 of 14 patients with gram-positive septicemia had thrombocytopenia. Platelet survival studied demonstrated a decreased platelet survival. In 11 of 12 patients with severe thrombocytopenia (platelet count less than 50,000mul), there was laboratory evidence of intravascular coagulation. In contrast, there was little evidence of intravascular coagulation in 8 of 11 patients with moderate thrombocytopenia (platelet counts 50,000 to less than 150,000/mul) or in 7 of 8 patients with normal platelet counts. This report indicates that while DIC accompanies thrombocytopenia in many patients with severe thrombocytopenia, there is frequently little evidence for intravascular coagulation in patients with moderate thrombocytopenia. It is apparent that factors other than intravascular thrombin must play a role in producing the thrombocytopenia of septicemia.

Adult↗
PubMed1979

Auxanographic grouping and typing of Neisseria gonorrhoeae.

Nearly 96% of 1297 Neisseria gonorrhoeae isolates in Hamilton were assigned to six major auxanographic groups (non-requiring or NR, Pro-, Orn-, Pro-Cit-Ura-, Orn-Ura-Hyx-, Cit-Ura-Hyx-) as established by requirements for none, or any one or more of proline, uracil, hypoxanthine, citrulline (Cit-), or citrulline replaceable by ornithine (Orn-) on chemically defined medium modified from Catlin (1973). Seven other groups, and strains not growing, accounted for 4.2%. The most common groups were Orn-Ura-Hyx- (25.6%) and Pro-Cit-Ura (31.8%). This latter group has not been previously described. These "Pro Cit/Orn Ura Hyx" criteria were among the most unequivocal to interpret; with rare exceptions for proline, a requirement was shown by absence of growth at any time in the zones of inoculation from a replicator. For some strains, some of the possible additional requirements (leucine, valine, isoleucine, glutamine, threonine, serine, histidine, etc.) could be less readily ascertained, because an occasional manifestation was to reduce the amount of growth, or to slow down the rate of growth, compared to complete medium. The first four of the six groups were the least fastidious, in that few strains had any additional requirements. About 2% of strains were inhibited by 0.25 mM phenylalanine.

Amino Acids↗
PubMed1979

Silver-resistant Enterobacteriaceae from hospital patients.

The inclusion of agar medium containing 0.5 mM AgNO3 in the hospital laboratory replicating system for routine antibiotic-susceptibility determinations resulted in identification of species of Enterobacteriaceae (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Proteus mirabilis, and Citrobacter freundii) with silver resistance. Since the study began in October, 1975, 11 in-hospital patients receiving silver sulfadiazine for burn wound prophylaxis have yielded silver-resistant bacteria from their infected burns. During this treatment routine burn-site cultures from these patients yielded 230 isolates of Enterobacteriaceae, including 211 which were sulfonamide-resistant, 97 of which were also silver-resistant, and 38 of which were untested for silver resistance. Seven silver-resistant but sulfonamide-sensitive isolates were incidentally recovered from respiratory specimens from four nonburn patients with silver tracheostomy tubes, one silver-resistant sulfonamide-sensitive isolate was recovered from a small infected burn on the foot of an Emergency Room patient. Previous treatment of this burn was unknown. Representative AgNO3-resistant E. coli isolates from four patients were serologically untypable. Serotyping of representative isolates of K. pneumoniae showed a diversity of types except from two patients who had been in the same ward at the same time.

Burns↗
PubMed1977

Nosocomial urinary tract infections caused by two O-serotypes of Providencia stuartii in one hospital.

Providencia stuartii nosocomial urinary tract infections occurring in the same hospital over an 18-month period of retrospective study were shown, by serotyping and biotyping, to have been caused by two endemic strains. Two episodes, involving 38 patients in one ward and 11 patients in another, were caused by a mannitol-positive strain of serotype O55. Transmission of the strain through the movements of one patient appeared to have been the basis for the introduction of the agent from one ward to the other. In another episode, involving two patients in a third ward, the infections were caused by a mannitol-negative strain of serotype O49. The study demonstrated the usefulness of serotyping and biotyping in epidemiological studies of infections caused by P. stuartii.

Bacteriuria↗
PubMedDate not supplied

Association between the auxogroup of Neisseria gonorrhoeae and the minimal inhibitory concentration of penicillin.

The auxogroups and the minimal inhibitory concentrations (MICs) of penicillin for 885 recently isolated strains of Neisseria gonorrhoeae were determined. Auxogroups were established according to the growth requirements of the strains for proline (Pro-), uracil (Ura-), hypoxanthine (Hyx-), citrulline (Cit-), or citrulline replaceable by ornithine (Orn-). The seven most common auxogroups studied were: Pro-Cit-Ura- (38.8%), Orn-Hyx-Ura- (24.1%), nonrequiring (NR) strains (13.4%), Pro- (9.7%), Orn- (5.2%), Cit-Hyx-Ura- (4.2%), and Pro-Onr-Hyx-Ura- (2.0%). The distribution of MICs of penicillin for the complete set of 885 strains had a bimodal distribution, with a minor peak at 0.01 microgram of penicillin/ml and a major one at 0.16 microgram/ml. The auxogroups, however, had different patterns of distribution of MICs of penicillin. Five patterns of distribution were found among eight auxogroups identified. (1) Orn- and NR auxogroups showed a broad distribution of MICs, with peak at 0.08 microgram/ml. (2) Of the Cit-Hyx-Ura- and Orn-Hyx-Ura- auxogroups, greater than 98% of strains were susceptible to less than or equal to 0.04 microgram of penicillin/ml. (3) All strains of the Pro-Orn-Hyx-Ura- and Pro-Cit-Hyx-Ura- auxogroups were susceptible to less than or equal to 0.08 microgram of penicillin/ml. (4) More than 95% of strains of the Pro-Cit-Ura- auxogroup required greater than of equal to 0.08 microgram of penicillin/ml for inhibition of growth. (5) The Pro- auxogroup showed a bimodal distribution, with a major peak at 0.01 microgram of penicillin/ml and a minor one at 0.32 microgram/ml.

Citrulline↗
PubMedDate not supplied

Value of the gram-stained urethral smear in the management of men with urethritis.

The value of the gram-stained urethral smear in clinical decision-making was assessed in a study of 250 men attending a clinic for sexually transmitted diseases. Of the 250 men, 132 (52.8%) had objective evidence of urethritis. Neisseria gonorrhoeae and/or Chlamydia trachomatis was isolated from 94 patients (37.6%). No pathogens were isolated from 38 patients (15.2%) who were diagnosed as having urethritis. Although the specificity (0.95) and positive predictive value (0.95) of the gram smear for culture-proved urethral infection was high, the relatively low sensitivity (0.66) and negative predictive value (0.63), led us to conclude that the test was of limited value in diagnosis and therapeutic decision-making when the patient was first seen. The decision to treat a patient should be based on a reliable history of dysuria and/or a urethral discharge in a patient at risk of infection, with or without an observable urethral discharge. Nevertheless, a gram smear should be done for all patients who are diagnosed presumptively as having urethritis, because it may be the only objective evidence of urethritis.

Chlamydia Infections↗