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Biomedical subjects

B Toye

Publications and source records attributed to B Toye.

31 records · Page 2Linked to original sources
PubMed1996

Culture of dialysate in suspected CAPD associated peritonitis using the BacT/Alert system.

The BacT/Alert blood culture system was evaluated as a method of culturing dialysates by comparing inoculation of culture bottles directly (DBTA) or after centrifugation of 50 mL of dialysate (CBTA) with conventional culture. Of the 122 dialysates cultured, 84 were positive by one of the 3 methods. After eliminating contaminants, DBTA and CBTA detected 84% (59 of 70) and 93% (65 of 70) of the positive cultures, respectively, compared to 77% (54 of 70) for conventional culture. CBTA and DBTA detected 87% (82 of 94) and 73% (68 of 94) of the significant organisms isolated, respectively, compared to 61% (57 of 94) by conventional culture. However, 60% of the contaminants occurred with the CBTA method. When a dialysate was positive by all 3 methods, both BacT/ Alert methods detected growth earlier by a mean of almost 19 hours. The BacT/Alert system is a useful alternative method for culturing dialysates with the advantages of an earlier detection of positive cultures and minimal handling for the processing of negative cultures.

Bacteriological Techniques↗
PubMed1996

Three-year outbreak of pseudobacteremia with Burkholderia cepacia traced to a contaminated blood gas analyzer.

Between November 1990 and June 1993, Burkholderia cepacia was isolated from the blood cultures of 13 neonates born at the Ottawa General Hospital. Eight of the 13 neonates appeared symptomatic, and only 4 were treated with appropriate antimicrobial therapy, but all improved clinically. In August 1993, the blood gas analyzer in the neonatal intensive-care unit was found to be contaminated heavily with B cepacia. Eight available patient isolates were identical to the isolates recovered from the blood gas analyzer by ribotyping analysis. Infection control measures were implemented to prevent future contamination of the analyzer, and no further cases have been identified.

Bacteremia↗
PubMed1996

Diagnosis of Chlamydia trachomatis infections in asymptomatic men and women by PCR assay.

A PCR assay was evaluated for its ability to detect genital chlamydial infection in asymptomatic men and women. Urethral swab specimens were collected from 472 men for culture and PCR assay, and first-void urine (FVU) specimens were collected from 379 of these men for enzyme immunoassay (EIA) and PCR assay. Cervical swab specimens were collected from 242 women for culture, EIA, and PCR assay. Patients were considered infected if they were culture positive or positive by PCR with both plasmid- and major outer membrane protein-based primers. By using this extended "gold standard," the prevalence of infection in this population was 7.6% for men and 7.9% for women. For men, the sensitivities of urethral swab specimen culture and PCR and FVU specimen EIA and PCR were 61, 72, 55, and 91%, respectively. All assays had specificities of > or = 99.8%. The positive and negative predictive values for PCR testing of FVU specimens were 100 and 99.4%, respectively, compared with values of 96.3 and 97.8%, respectively, for PCR of urethral swab specimens. The sensitivities of cervical swab specimen culture and PCR testing were 42 and 90%, respectively, with corresponding specificities of 100 and 99.3%. All cervical swabs were negative by EIA. Molecular techniques such as PCR assays are valuable tools for the detection of symptomatic genital chlamydial infection. In particular, PCR assays of FVU specimens from men offer a highly sensitive, noninvasive screening tool that will likely improve patient compliance for diagnostic testing.

Adult↗
PubMed1995

Serologic evidence of Chlamydia trachomatis infection and risk of preterm birth.

OBJECTIVE: To determine whether serologic evidence of Chlamydia trachomatis during pregnancy is a risk factor for preterm delivery (before 37 weeks' gestation). DESIGN: Chart review. SETTING: Antenatal clinics associated with a teaching hospital. PATIENTS: A group of 103 unselected consecutive patients presenting for routine prenatal care. OUTCOME MEASURES: Pregnancy outcome and C. trachomatis serologic status. RESULTS: A total of 21 women (20%) were found to be seropositive for IgG antibodies to C. trachomatis. They were similar to the seronegative women with respect to maternal age, parity, history of preterm birth, obstetric or medical problems, smoking status, history of drug abuse, educational status and psychosocial stressors. The seropositive women were significantly more likely than the seronegative women to have a preterm birth (24% [5/21] v. 7% [6/82]i p = 0.029, odds ratio 3.96, 95% confidence interval 1.08 to 14.57), an infant with a lower mean gestational age at birth (262 [standard deviation (SD) 19] days v. 273 [SD 15] days; p = 0.0052) and an infant with a lower mean birth weight (3125 [SD 692] g v. 3473 [SD 696] g; p = 0.0434). The positive predictive value of a seropositive result for preterm birth was 31% (5/16); the negative predictive value of a seronegative result for preterm birth was 8% (6/76). CONCLUSION: Women with serologic evidence of C. trachomatis may be at risk for preterm birth. Further study is required to determine whether serologic testing for C. trachomatis should be a routine part of prenatal care.

Adult↗
PubMed1994

Comprehensive typing of DR52 (DRB3)-associated DRB1 and DRB3 alleles by PCR-RFLP.

The DR52-associated DRB1 and DRB3 alleles were resolved by PCR-RFLP. Second exon was amplified using four primer pairs (groups 1-4) for DRB1 and a pair for DRB3 alleles. Except for three endonucleases, all others had either none or only one site for a specific amplified product. Group 1 primers amplify 10 DRB1 alleles (DRB1*0302, 1101, 1302, 1303, 1305, 1307, 1402, 1403, 1407 and 1409). All but one pair, DRB1*1402 from 1409, could be resolved using seven endonucleases (ApaI, SacII, FokI, AvaII, BsaAI, BsrBI and SfaNI). Group 2 consisted of four alleles (DRB1*1201, 1202, 1404 and 1411) that can be resolved along with co-amplified DRB1*0804 and 0806 using five endonucleases (AvaII, SacII, FokI, HaeII and RsaI). Group 3 primers amplify 15 DRB1 alleles (DRB1*0301, 0303, 1102, 1103, 1104, 1107, 1301, 1304, 1306, 1308, 1401, 1405, 1406, 1408 and 14-New), which can be resolved using nine enzymes (KpnI, AvaII, FokI, SacII, HaeII, BsrBI, SfaNI, DdeI and RsaI). BsrBI, a new endonuclease, can resolve DRB1*1301 from 1306 and the previously unresolved allele DRB1*1103 from 1104. DRB1*1410, co-amplified with DR4 group-specific primers, is resolved with PstI which cleaves all DR4 alleles but not DRB1*1410. All four DRB3 alleles (DRB3*0101, 0201, 0202 and 0301) and their heterozygotes are resolved using two endonucleases, RsaI and HphI. Thirty-four DR52-associated alleles and their heterozygotes can be unambiguously resolved, except for DRB1*1402 from 1409.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1994

Risk factors for acquiring ampicillin-resistant enterococci and clinical outcomes at a Canadian tertiary-care hospital.

The number of ampicillin-resistant enterococci (ARE) was noted to be increased at our teaching hospital. To determine the risk factors for acquiring this organism and to compare clinical outcomes, over a 5-month period 38 patients infected or colonized with ARE were compared with 76 patients, infected or colonized with ampicillin-susceptible enterococci (ASE). Risk factors included nosocomial acquisition, duration of hospitalization, admission to a medical service, prior antimicrobial therapy, and combination therapy for at least 7 days. The mortality rate of patients infected or colonized with ARE was higher than that of patients infected or colonized with ASE (34 versus 14%; P = 0.03), but most deaths did not appear to be related to enterococcal infection. Over a 2-year period, 16 patients with ARE bacteremia were also compared with 23 patients with ASE bacteremia. The risk factors associated with ARE bacteremia also included nosocomial acquisition, duration of hospitalization, and prior antimicrobial therapy. The mortality of patients with ARE bacteremia was also higher than that of patients with ASE bacteremia (81 versus 30%; P = 0.003), with most deaths being due to the underlying disease or a complication of it. Typing of ARE isolates by pulsed-field gel electrophoresis showed that two genotypes predominated in our institution. A prolonged hospital stay, exposure to multiple antimicrobial agents, and perhaps nosocomial transmission are important factors in acquiring ARE. The presence of ARE may also be a marker for poor outcome.

Adolescent↗
PubMed1993

Association between antibody to the chlamydial heat-shock protein and tubal infertility.

To determine the prevalence of antibody to Chlamydia heat-shock protein 60 (C-hsp60) in women with tubal infertility, an ELISA using purified recombinant C-hsp60 was developed. Antibody to C. trachomatis was present in 32 (72.7%) of 44 women with tubal infertility compared with 9 (32.1%) of 28 with other causes of infertility and 55 (28.9%) of 190 pregnant women (P < .001). Among the seropositive women, antibody to C-hsp60 was present in 26 (81.3%) of 32 women with tubal infertility compared with 0 of 9 with other causes of infertility and 9 (16.4%) of 55 pregnant women (P < .001). The C-hsp60 ELISA detected Chlamydia-associated tubal infertility in infertile women with a sensitivity of 81.3% and a specificity of 97.5%. There is a strong association between antibody response to the C-hsp60 and the development of Chlamydia-associated tubal infertility. Thus, a C-hsp60 ELISA may be useful as a predictor for poor fertility outcome.

Antibodies, Bacterial↗
PubMed1992

Alteration of the carbohydrate binding specificity of verotoxins from Gal alpha 1-4Gal to GalNAc beta 1-3Gal alpha 1-4Gal and vice versa by site-directed mutagenesis of the binding subunit.

Verotoxin 1 (VT-1) and Shiga-like toxin II (SLT-II) bind to the glycosphingolipid (GSL), globotriaosylceramide (Gb3), whereas pig edema disease toxin (VTE) binds to globotetraosylceramide (Gb4) and to a lesser degree Gb3. Amino acids important in the GSL binding specificity of VT-1 and VTE have been identified by site-directed mutagenesis. One mutation, Asp-18----Asn, in VT-1 resulted in binding to Gb4 in addition to Gb3 in a manner similar to VTE. Several mutations in VTE resulted in the complete loss of GSL binding; however, one mutation resulted in a change in the GSL binding specificity of the VTE B subunit. The double mutation Gln-64----Glu and Lys-66----Gln (designated GT3) caused a selective loss of Gb4 binding, effectively changing the binding phenotype from VTE to VT-1. Both wild-type VTE and GT3 were purified to homogeneity and binding kinetics in vitro were determined with purified GSLs from human kidney. The cell cytotoxicity spectrum of the mutant toxin was also found to be altered in comparison with VTE. These changes were consistent with the GSL content of the target cells.

Amino Acid Sequence↗
PubMed1992

Broth microdilution testing of Haemophilus influenzae with haemophilus test medium versus lysed horse blood broth. Canadian Haemophilus Study Group.

Broth microdilution testing of 702 community-acquired isolates of Haemophilus influenzae from across Canada was performed with both Mueller-Hinton broth supplemented with 3% lysed horse blood broth (LHB) (BBL Microbiology Systems, Cockeysville, Md.) and haemophilus test medium (HTM). The prevalence of beta-lactamase production was found to be 26% with no regional variation. MICs determined with LHB tended to be higher than those with HTM, but interpretive errors due to these differences were observed only rarely with trimethoprim-sulfamethoxazole (n = 5), cefaclor (n = 8), and cefamandole (n = 3). The interobserver variability in MIC determinations was found to be greater when LHB was used than when HTM was used. There was no difference in intraobserver variability between the two medium formulations. beta-Lactamase-positive isolates developed false resistance to amoxicillin-clavulanate 2 weeks after microdilution panels of both types of medium were stored at -20 degrees C but not when panels were stored at -70 degrees C. In conclusion, this study supports the use of HTM rather than LHB for sensitivity testing of H. influenzae because of its lower rate of interobserver variability and its ability to support the growth of these organisms, which is comparable to that of LHB.

Amoxicillin↗
PubMed1990

Immunologic characterization of a cloned fragment containing the species-specific epitope from the major outer membrane protein of Chlamydia trachomatis.

A 183-bp fragment encoding variable domain IV (VD IV) of Chlamydia trachomatis serovar B major outer membrane protein (MOMP) (amino acids 273 to 333) and containing the species-specific epitope was cloned and expressed in Escherichia coli as a fusion protein with Schistosoma japonicum glutathione S-transferase (GST-VD IV). The fusion protein was affinity purified under nondenaturing conditions and used to immunize rabbits. Antisera were characterized by microimmunofluorescence, immunoblot, dot blot, peptide enzyme-linked immunosorbent, and in vitro neutralization assays. Antisera recognized MOMP from all 12 tested serovars of C. trachomatis but not from Chlamydia psittaci. In a dot blot assay, antisera bound to elementary bodies of serovars B, D, E, L2, and K in a strong fashion and to elementary bodies of serovars F, G, A, and H in a weak fashion but not to elementary bodies of serovars C, J, and I. High-resolution peptide mapping with synthetic overlapping serovar B MOMP peptides in a solid-phase enzyme-linked immunosorbent assay showed that immunization with GST-VD IV produced a serologic response that closely mimicked the response produced with purified serovar B elementary bodies. Antipeptide antibodies with strong binding to species- and subspecies-specific epitopes were elicited. Antisera were able to neutralize only those C. trachomatis serovars that bound antibodies in the dot blot assay. These results suggest that antigenic fragments from VD IV containing the species-specific epitope may be useful in the construction of a chlamydial vaccine for some but not all C. trachomatis serovars.

Animals↗
PubMed1981

Measurement of ventilation in children using the respiratory inductive plethysmograph.

A new technique to measure ventilation, based on the separate contributions of rib cage and abdomen to tidal volume, the respiratory inductive plethysmograph was evaluated in 20 healthy children. The accuracy of the method was determined by simultaneously measuring tidal volume with a pneumotachograph in the standing, sitting, supine, left lateral decubitus, and prone postures. Comparison of these two techniques showed mean correlation coefficients greater than 0.96, mean slopes between 0.98 and 1.11, and mean SEE of less than 8% in all postures studied. Breathing through a mouthpiece connected to a pneumotachograph resulted in a substantial change in the pattern of breathing and a mean increase in tidal volume of 32% (P less than 0.05). In the standing and sitting postures, rib cage contribution to tidal volume was predominant (greater than 65%) whereas in the recumbent postures abdominal contribution was predominant (greater than 61%). We conclude that the RIP is an accurate means of measuring ventilation in children and that it avoids the artifacts caused by using a conventional respiratory measuring apparatus.

Abdomen↗
PubMedDate not supplied

Staphylococcus epidermidis septic arthritis post arthroscopy.

A 61 year-old man developed painful swelling of his right knee shortly after arthroscopy of the joint. Synovial fluid analysis revealed a polymorphonuclear leukocytosis of 51,600 X 10(6) cells/litre and culture grew Staphylococcus epidermidis. He responded favorably to 4 weeks of intravenous therapy with cloxacillin. S. epidermidis, an important cause of prosthetic joint infection, must be considered a potential pathogen in other joint infections.

Arthritis, Infectious↗