Biomedical subjects
Publications and source records attributed to F J Roberts.
A 23-year retrospective study of acid fast stains of unconcentrated gastric aspirate specimens revealed a specificity of 99% and a sensitivity of 30%. All positive smears were from patients with culture-proven mycobacterial disease. Although the sensitivity is low, a positive smear allows a significantly earlier identification of patients with mycobacterial infections when compared to culture.
The effect of daily treatment with three current topical antibacterial agents and four experimental formulations of chlorhexidine was evaluated after 1 week in rats with full thickness burns. The burn was seeded with 1 x 10(8) colony forming units (CFU) of a strain of P. aeruginosa isolated from the infected wound of a burn patient. Mafenide acetate resulted in the lowest incidence of muscle invasion and yielded the lowest mean eschar and muscle concentrations. Mafenide acetate, gentamicin, and chlorhexidine diphosphanilate (0.5 per cent) had lower mean eschar and muscle concentrations than silver sulphadiazine 1 per cent alone. Addition of chlorhexidine digluconate (0.5 per cent or 1.0 per cent) to silver sulphadiazine reduced mean eschar concentrations but not muscle concentrations compared to silver sulphadiazine alone. All treatments effectively suppressed systemic invasion of lung and blood and prevented death compared with controls. Mafenide acetate, gentamicin sulphate and chlorhexidine disphosphanilate 0.5 per cent were most effective against this patient strain of P. aeruginosa.
A difficulty encountered during antimicrobial clinical trials is to determine whether a patient's death was related to uncontrolled bacteremia or other factors. Because the postmortem spleen culture correlates with untreated antemortem bacteremia, a study was performed to determine the association of the duration of appropriate antimicrobial therapy with the recovery of the blood culture organism from the postmortem spleen. During the last 10 days of life, blood cultures from 79 patients yielded 85 organisms. The spleen yielded 96%, 55%, 41%, and 35% of the blood culture organisms in patients receiving appropriate antibiotics for 0, less than 2, 2-4, and greater than 4 days, respectively. Statistical analysis with the use of chi-square test for stratified data showed this to be a significant trend. This correlation suggests that postmortem spleen cultures may be of value in assessing antimicrobial therapy in patients dying within ten days of proven bacteremia.
A study was made of quantitative urine cultures in bacteremic patients with urinary tract infection as the only identifiable source. These patients represent the most serious form of urinary tract infection and should be recognized as significant by the criteria used for interpreting quantitative urine cultures. In 83 patients, 15 (18%) had quantitative urine counts less than 10(5) colony-forming units (CFU)/mL. Ten (12%) had counts between 10(4) and 10(5) CFU/mL. The incidence of patients with less than 10(4) CFU/mL (5%) is probably a low estimate because of the urine culture methods used, and this requires further study. The results of this study support the view that significant urinary infections may be associated with quantitative urine counts of less than 10(5) CFU/mL.
Patients with fresh full-thickness burn wounds were randomly assigned to receive wound treatment with daily applications of either 1 per cent silver sulfadiazine plus 0.2 per cent chlorhexidine digluconate cream (Silvazine) or 1 per cent silver sulfadiazine (Flamazine). Fifty-four patients treated with Silvazine were comparable to 67 treated with Flamazine with respect to extent and distribution of burn, age and all aspects of wound and associated treatment. Overall incidence of wound bacterial colonization was less in the Silvazine treated patients (65 per cent versus 88 per cent; P = 0.002). With Silvazine, wound colonization by Staphylococcus aureus was less (41 per cent versus 64 per cent; P = 0.01). Clinical wound infection with Staph, aureus developed in one Silvazine treated patient and five Flamazine treated patients (P = 0.16). Colonization by and infection due to all other organisms did not differ in the two groups. The incidence of graft failure was similar with both agents. In future increasing the concentration of chlorhexidine digluconate above 0.2 per cent might produce an improved prophylactic effect against Gram negative bacteria reported by other authors using the combined agent in in vitro and clinical trials. Silvazine was effective in reducing the incidence of Staph. aureus burn wound colonization without fostering supervening opportunistic infection.
Microbial cultures were performed on 163 lymph-node biopsies from a variety of sites and in all age groups. Growth occurred in 76 (47%), 41 of which were considered contaminants. The final diagnoses were as follows: mycobacterial infection (27 biopsies), coccidioidomycosis (two cultures), nonspecific inflammatory changes (82 cultures), malignancy (51 cultures), and Whipple's disease (one culture). Microbial culture was the sole means of diagnosing nine cases of mycobacterial infection. The fluorescent stain demonstrated acid-fast bacilli in only 16 biopsies, twice the frequency with the standard Ziehl-Neelson stain. Other bacterial isolates were of uncertain significance in most instances. Routine culture for mycobacteria and fungi is recommended for all lymph nodes that show granulomatous changes.
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The records of all patients with Staphylococcus aureus meningitis admitted to Vancouver General Hospital between 1956 and 1981 were reviewed. All the patients had clinical and laboratory features of meningitis, and in all cases S. aureus was isolated from the cerebrospinal fluid. S. aureus was responsible for 21 (3%) of the 710 cases of acute bacterial meningitis. Therapy with cloxacillin or methicillin, or both, with or without other agents, was successful in 14 of the 21 patients. Three of the 14 patients without ventricular shunts died, 2 with fulminating septicemia and 1 with a postoperative brain abscess treated with cloxacillin. Following shunt removal and antibiotic therapy all seven patients with ventricular shunts survived the infection. Shunt removal may therefore be essential in appropriate cases.
A case report of a patient with tonsillitis and peritonsillar abscess, who subsequently developed fatal myocarditis, is presented. The clinical course and pathological findings are outlined. The rare association of tonsillitis and pharyngitis with non-rheumatic, non-diphtheritic, non-fatal myocarditis was recognized and reported in the pre and early antibiotic era. The present reported case is only the second recent description of fatal myocarditis associated with tonsillitis, and the first ever reported in the English Otolaryngologic literature.
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In a comparison of the radiometric BACTEC 460 (Johnston Laboratories) and the BCB broth slide system (Roche Diagnostics Division), the latter yielded a slightly greater number of clinically significant microorganisms, as well as contaminants, from aerobic blood cultures. These differences may reflect the larger volume of blood required for and the greater amount of manipulation associated with the BCB.
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A patient with advanced renal failure and bilateral exophthalmos was found to have urinary obstruction caused by retroperitoneal fibrosis, as well as bilateral orbital pseudotumors. Pseudotumor of the orbit, especially when bilateral, has been associated with a wide variety of systemic conditions. Although the association of pseudotumor and retroperitoneal fibrosis is uncommon, any patient with bilateral orbital pseudotumor and renal insufficiency should be examined for the possible presence of a treatable urinary obstruction.
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A 60-item MCQ as administered to 46 fourth year medical students at the beginning, half-way, and at the end of a five week introductory clinical course. The stated goals were achieved: (1) a baseline measure was provided, indicating abilities brought by newly-arriving students; (2) data gave opportunity for "mid-course" corrections by students in their study and by tutors in their teaching; (3) overall student change was assessed, offering a measure of the educational effectiveness of the course, and (4) tutors were made aware of individual students requiring particular attention. Such assessment techniques provide an effective monitoring and motivating instrument at this level of medical education.
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