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Biomedical subjects

D A Bruckner

Publications and source records attributed to D A Bruckner.

At least 19 recordsLinked to original sources
PubMed1992

Amebiasis.

Entamoeba histolytica, the causative agent of amebiasis, was first described in 1875. Although a large number of people throughout the world are infected with this organism, only a small percentage will develop clinical symptoms. Morbidity and mortality due to E. histolytica vary from area to area and person to person. Recent findings have suggested that there are pathogenic and nonpathogenic strains of E. histolytica that can be differentiated by isoenzyme (zymodeme) analysis, monoclonal antibodies, and DNA probes. Whether pathogenicity is a genotypic trait or can be changed by environmental influences has not been resolved. Exchange of genetic material between strains of amebae can influence zymodeme patterns. Currently, detection of E. histolytica infections depends on examinations for ova and parasites and on serologic tests; however, the development of monoclonal antibodies and DNA probes specific for pathogenic zymodemes may be beneficial for clinical laboratory testing and therapeutic decisions when approved tests become available. A better understanding of the mechanisms of pathogenicity at the molecular level is evolving and should promote the development of vaccines and better target selection for therapeutic agents.

Animals↗
PubMed1992

Evaluation of a new monoclonal antibody combination reagent for direct fluorescence detection of Giardia cysts and Cryptosporidium oocysts in human fecal specimens.

Giardia lamblia and Cryptosporidium parvum can cause severe symptoms in humans, particularly in the immunologically compromised. Monoclonal antibody reagents offer increased sensitivity and an excellent alternative to conventional staining methods. These reagents are helpful when screening large numbers of patients or those with minimal symptoms. Problems of false-positive and false-negative results with routine staining methods for stool parasites can be eliminated with monoclonal antibody reagents. Known positive formalinized specimens [Giardia sp. (n = 60), Cryptosporidium sp. (n = 55), and mixed Giardia-Cryptosporidium spp. (n = 10)] and negative formalinized specimens (n = 105), of which 46 contained other yeast or human cells or protozoa), were tested by the MERIFLUOR Cryptosporidium-Giardia direct immunofluorescence detection procedure. The MERIFLUOR reagent exhibited +/- to 4+ (majority, 2+ to 3+) on all Giardia cysts and 2+ to 4+ (majority, 3+ to 4+) on all Cryptosporidium oocysts. The cysts were generally oval (11 to 15 microns), while the oocysts were round (4 to 6 microns); both showed apple-green fluorescence against a background free of nonspecific fluorescence. All specimens positive for Giardia sp. and/or Cryptosporidium sp. showed fluorescence, and all specimens negative for the two organisms showed no fluorescence. There were eight specimens previously negative by the ova and parasite examination which were positive by the direct fluorescence method; four contained Giardia sp., and four contained Cryptosporidium sp. These positive results were confirmed after the examination of additional trichrome and modified acid-fast smears. The MERIFLUOR reagent was very easy to use, and even with a lower fluorescence intensity for Giardia sp. cysts, no false-negative or false-positive results among the specimens tested for either organism were found.

Animals↗
PubMed1992

Mycobacterium fortuitum keratitis. Clinicopathologic correlates and corticosteroid effects in an animal model.

Mycobacterium fortuitum keratitis is an indolent infection of traumatized corneas in humans. To study this disorder in an animal model, 10(4) M fortuitum organisms (10 microliters) were inoculated into the stroma of both corneas of 16 New Zealand albino rabbits. Eight of the rabbits were also given bilateral subconjunctival injections of methylprednisolone acetate (20 mg in 0.5 ml) at the time of inoculation. Two corticosteroid-treated and two untreated rabbits were selected each week after inoculation for histopathological examination and quantitative cultures. Corneal lesions in corticosteroid-treated eyes were characterized clinically by indolent ulcerations and satellite lesions that slowly enlarged; on histopathologic examination at each week, acute inflammation and microorganisms were consistently present. Corneal lesions in untreated eyes were characterized clinically by small infiltrates that progressed little over time; at weeks 1 and 2, light microscopic examination showed intrastromal granulomatous and/or mixed acute and chronic inflammation with focal intrastromal necrosis, but at weeks 3 and 4 there was no evidence of active disease. Organisms could not be identified microscopically in corneas of any untreated rabbits. Mean values for quantitative cultures of corneas were higher in corticosteroid-treated rabbits after week 1, although standard deviations were large. These results suggest that M fortuitum keratitis in rabbits is made worse by corticosteroid use. Clinical and histopathologic changes were compared with human disease and found to be similar in corticosteroid-treated rabbits.

Animals↗
PubMed1992

Mycobacterium fortuitum keratitis. A comparison of topical ciprofloxacin and amikacin in an animal model.

The effect of topical amikacin or topical ciprofloxacin on Mycobacterium fortuitum keratitis was studied in a rabbit model. Two strains of M fortuitum were used: ATCC-6841 [for which mean inhibitory concentrations (MICs) indicated in vitro sensitivity to both drugs] and a cutaneous isolate from a human infection (for which MICs indicated relative in vitro resistance to amikacin but in vitro sensitivity to ciprofloxacin). Both drugs reduced the number of organisms in eyes infected with either strain (all p values < or = 0.01), but in no cases were organisms eliminated from eyes after 4 days of treatment. Amikacin was more effective in reducing the number of organisms in corneas infected with ATCC-6841 than in corneas infected with the patient isolate (p = 0.004), whereas ciprofloxacin was equally effective for treatment of both strains (p > 0.10). These results suggest that topical amikacin or ciprofloxacin may be useful in the treatment of M fortuitum keratitis. However, neither drug was shown to be more effective for treatment of either strain studied (all p values > 0.3).

Amikacin↗
PubMed1991

Beta-lactam antibiotic therapy in febrile granulocytopenic patients. A randomized trial comparing cefoperazone plus piperacillin, ceftazidime plus piperacillin, and imipenem alone.

OBJECTIVE: To compare the efficacy, toxicity, and cost-effectiveness of double beta-lactam therapy with monotherapy. DESIGN: A randomized, controlled trial. PATIENTS: Febrile, granulocytopenic patients (429). INTERVENTIONS: Patients were randomly assigned to receive iv cefoperazone (3 g every 12 hours) plus piperacillin (75 mg/kg body weight every 6 hours), ceftazidime (2 g every 8 hours) plus piperacillin (75 mg/kg every 6 hours), or imipenem alone (1.0 g or 0.5 g every 6 hours). Patients also received prophylactic vitamin K. MEASUREMENTS: Clinical improvement, eradication of the infecting organism, and toxicity in 403 evaluable patients with one or more infections. MAIN RESULTS: Cefoperazone and ceftazidime, when given in combination with piperacillin, were equally effective (response rates of 75% (104 of 138 patients) and 74% (101 of 137 patients), respectively). Monotherapy with imipenem had a response rate of 82% (111 of 136 patients) and was as effective as double beta-lactam therapy. Overall antibiotic-related toxicity was minimal, although seizures were associated with high doses of imipenem. Seizures occurred in 3 of 29 patients (10.3%) who were receiving 4 g/d of imipenem, in 3 of 136 patients (2.2%) who were receiving cefoperazone plus piperacillin, in 0 of the 132 patients who were receiving ceftazidime plus piperacillin, and in 1 of 106 patients (0.9%) who were receiving 2 g/d of imipenem (P less than 0.005). The 2-g daily dose of imipenem was as effective as the 4-g daily dose. Diarrhea was more frequent in patients receiving cefoperazone, whereas nausea occurred more often with imipenem. No antibiotic-related hemorrhage or nephrotoxicity was observed. Superinfections caused by beta-lactam-resistant, gram-negative bacilli were uncommon but occurred more frequently with double beta-lactam therapy than with imipenem monotherapy (11 of 268 patients compared with 1 of 135 patients; P = 0.06). Xanthomonas maltophilia superinfections occurred only in patients receiving imipenem (3 of 135 patients compared with 0 of 268 patients; P = 0.03). Imipenem monotherapy was the least expensive therapy. CONCLUSIONS: Cefoperazone and ceftazidime were equally effective when used in combination antibiotic therapy with piperacillin. Twice-daily cefoperazone is less expensive than ceftazidime given three times daily. Monotherapy with imipenem, at a daily dose of 2 g, is as efficacious as double beta-lactam therapy and costs less than combination therapy.

Adolescent↗
PubMed1991

Comparison of API Rapid Strep, Baxter MicroScan Rapid Pos ID Panel, BBL Minitek Differential Identification System, IDS RapID STR System, and Vitek GPI to conventional biochemical tests for identification of viridans streptococci.

Viridans group streptococci (36 stock strains and 167 single patient blood culture isolates) were assessed using API Rapid Strep, Baxter MicroScan Rapid Pos ID Panel, BBL Minitek Differential Identification System, IDS RapID STR System, and Vitek GPI methods. Identification data obtained with these systems were compared with those indicated by conventional biochemical procedures. API, Baxter MicroScan, BBL, IDS, and Vitek corresponded with conventional biochemical identification in 74%, 66%, 65%, 50%, and 61% of the isolates, respectively; using recommended supplemental tests, agreement was augmented in 9%, 11%, 20%, 11%, and 21% of the isolates, respectively. Disagreement with conventional biochemical methods occurred in 14%, 17%, 14%, 32%, and 10% of the commercial techniques, respectively; no identification was possible in 2%, 5%, fewer than 1%, 6%, and 8% of specimens, respectively. BBL, API, and Baxter MicroScan systems provided the most reliable rapid identification, although supplemental testing often was required. Until a higher percentage of correct identification data can be obtained without supplemental procedures, conventional biochemical techniques will remain the methods of choice for identification of viridans streptococci.

Bacteriological Techniques↗
PubMed1990

Ofloxacin versus vancomycin/polymyxin for prevention of infections in granulocytopenic patients.

INTRODUCTION: The efficacy and safety of oral ofloxacin were compared with those of vancomycin/polymyxin for prophylaxis of bacterial infections in granulocytopenic patients undergoing chemotherapy for hematologic malignancy. PATIENTS AND METHODS: Antimicrobial prophylaxis was begun at the time of initiation of chemotherapy. Thirty patients received ofloxacin tablets (300 mg orally every 12 hours) plus a nystatin suspension. Thirty-two patients received vancomycin capsules (500 mg orally every eight hours) and polymyxin capsules (100 mg orally every eight hours) plus a nystatin suspension. RESULTS: In the group of patients receiving ofloxacin, there were a lower number of acquired gram-negative bacillary organisms per patient (0.13 versus 1.37, p less than 0.00005), fewer patients with documented infection (11 of 30 versus 21 of 32, p = 0.04), and fewer cases of gram-negative septicemia (zero of 30 versus five of 32, p = 0.05). Ofloxacin was also better tolerated (24 of 30 versus 10 of 32 patients highly compliant, p = 0.01) and associated with fewer gastrointestinal side effects (one of 30 versus nine of 32 patients with gastrointestinal side effects, p = 0.01) than vancomycin/polymyxin. However, except for a reduction of Staphylococcus aureus colonization and infection by ofloxacin, neither ofloxacin nor vancomycin/polymyxin was effective in eliminating colonization or infection with viridans group streptococci, coagulase-negative staphylococci, or other gram-positive organisms. Only three isolates of ofloxacin-resistant gram-negative bacteria (Pseudomonas fluorescens, Pseudomonas putida, and Enterobacter aerogenes) were isolated from surveillance cultures, but none caused infection. CONCLUSION: These results suggest that oral ofloxacin is a more tolerable and efficacious alternative to vancomycin/polymyxin for prevention of serious gram-negative bacillary infections in granulocytopenic patients. More effective prophylaxis of gram-positive infections, however, is still needed.

Adolescent↗
PubMed1989

Microbial analysis of contact lens care systems contaminated with Acanthamoeba.

We analyzed bacterial and fungal contamination within the contact lens care systems of ten patients who had Acanthamoeba detected within their care systems. Seven patients had Acanthamoeba keratitis, one had Pseudomonas keratitis, and the remaining two were asymptomatic. Gram-negative bacteria were found in all ten care systems, and Pseudomonas was found in six. Bacillus species, the only gram-positive bacteria isolated, were found in five systems. Fungi were isolated in six care systems. The use of homemade saline and the two-cup method of peroxide disinfection were associated with microbial contamination. Acanthamoeba organisms were found only in contact lens cases or solutions that also had bacterial and in many cases fungal contamination, suggesting that the presence of bacterial and fungal contamination within the contact lens care system may be an important element for the survival and growth of Acanthamoeba.

Acanthamoeba↗
PubMed1989

In-vitro activity of dapsone and two potentiators against Mycobacterium avium complex.

The efficacy of dapsone against Mycobacterium avium, M. intracellulare, M. kansasii, M. fortuitum and M. tuberculosis was determined by disc elution in agar. The minimal inhibitory concentration at which 90% of the colony forming units were inhibited (90MIC) by dapsone was 8 mg/l for M. avium, M. intracellulare and M. kansasii and greater than or equal to 32 mg/l for M. tuberculosis and M. fortuitum. The 90MICs were confirmed by culturing these test organisms with dapsone in the BACTEC 460 system. Reduction of the 90MIC from 8 mg/l to 2 mg/l was observed by combining dapsone with either or both of the potentiators tested. The dapsone-potentiator combinations had no effect on the bacteria with 90MICs of greater than or equal to 32 mg/l. The clinical relevance of this drug combination against M. avium complex infections remains to be evaluated.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Comparison of direct immunofluorescent staining and an enzyme-linked immunoabsorbent assay for identifying Chlamydia trachomatis in cervical and urethral specimens.

A direct fluorescent antibody (DFA) stain (MicroTrak, Syva) and an enzyme-linked immunoabsorbent assay (Chlamydiazyme, Abbott) were used to detect chlamydial infection in 179 cervical specimens and 56 specimens obtained from the female urethra. Chlamydiazyme, when compared with the DFA technique, revealed a high degree of correlation in these specimens (22 and 21 positive cervical specimens, respectively, and 7 each positive urethral specimens). Since both techniques are readily available, inexpensive and easy to perform, they should become valuable tools in the objective assessment of women at risk of this common and important sexually transmitted disease.

Cervix Uteri↗
PubMed1988

Controlled trials of double beta-lactam therapy with cefoperazone plus piperacillin in febrile granulocytopenic patients.

The efficacy and safety of double beta-lactam therapy with cefoperazone plus piperacillin in febrile granulocytopenic patients were compared with moxalactam plus piperacillin, ceftazidime plus piperacillin, and imipenem alone in two separate clinical trials. All patients also received prophylactic vitamin K. When National Committee for Clinical Laboratory Standards breakpoints for susceptibility were used, a greater proportion of pretherapy isolates of gram-negative aerobic bacilli and gram-positive organisms were found to be susceptible to cefoperazone (94 percent) and imipenem (91 percent) than to moxalactam (84 percent), ceftazidime (85 percent), or piperacillin (85 percent). In trial I, the overall response rates for documented or possible infections were 78 percent (76 of 97 patients) for cefoperazone/piperacillin and 80 percent (72 of 90 patients) for moxalactam/piperacillin. In trial II, the overall response rates were 86 percent (25 of 29 patients) for cefoperazone/piperacillin, 74 percent (20 of 27 patients) for ceftazidime/piperacillin, and 72 percent (21 of 29 patients) for imipenem alone. There was no nephrotoxicity or hemorrhage related to the study drugs. Diarrhea was more frequent with each of the double beta-lactam regimens, whereas nausea and seizures were more common with imipenem given at a dosage of 1.0 g intravenously every six hours. Seizures occurred in three of 29 imipenem-treated patients but in none of 243 patients treated with the double beta-lactam regimens (p less than 0.001). These results suggest that cefoperazone plus piperacillin provides adequate coverage for most common bacterial pathogens and is safe and effective therapy for febrile granulocytopenic patients.

Adolescent↗
PubMed1988

DNA probe reactivity of Mycobacterium avium complex isolates from patients without AIDS.

Mycobacterium avium complex isolates from 27 patients without AIDS and from 76 patients with AIDS were analyzed with the Gen-Probe Rapid Diagnostic System for Mycobacterium avium complex, and a retrospective chart review was performed to determine clinical significance of the isolates. While 87% of isolates from AIDS patients reacted only with the M. avium probe, only 37% from non-AIDS patients were M. avium probe positive (p less than 0.001). This pattern among non-AIDS patients was also observed among the 13 patients from whom isolates were considered to be clinically significant. Reactivity to both probes occurred with three isolates, two from non-AIDS patients that were not clinically significant and one from an AIDS patient. Results of further testing suggested that these represented dual infection with two coexisting strains. Awareness of the differences in DNA probe reactivity between isolates from AIDS and non-AIDS patients may influence testing strategies in the clinical laboratory.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Incidence of Cryptosporidium in all patients submitting stool specimens for ova and parasite examination: monoclonal antibody IFA method.

The development of a monoclonal antibody to Cryptosporidium oocysts provides a more sensitive detection method than that seen using other diagnostic techniques. Incidence reports on this organism have been based on earlier, less-sensitive methods. In order to determine the numbers of positive patients and stool specimens, every stool specimen submitted for an ova and parasite examination was tested using the Merifluor IFA system (Meridian Diagnostics, Inc). Over a 12-mo period, 2,786 specimens were tested (1,516 patients). Positive specimens (23) were from nine known immunosuppressed patients and from four symptomatic immunocompetent patients. This represents an overall positive rate of 0.86% (patients). In those patients who were not suspected of having cryptosporidiosis (immunocompetent), diagnosis of this infection would not have been accomplished without the use of a sensitive screening method. This data, obtained over a 12-mo period, provides information for those laboratories considering the clinical relevance of screening all stool specimens for this infection. With the development of therapy, early detection of Cryptosporidium will become more important.

Animals↗
PubMed1988

Diagnostic efficacy of a nasotracheal protected specimen brush in patients with suspected bacterial pneumonia.

The diagnostic yield and safety of a novel nasotracheal protected specimen brush (PSB) were evaluated in 15 nonintubated adult patients with suspected bacterial pneumonia. A double-catheter PSB was passed directly through the anesthetized nose and into the trachea without bronchoscopy or fluoroscopy. Endotracheal brushing was performed in less than 10 sec, and the brush was immediately processed for Gram staining and quantitative aerobic and anaerobic cultures. According to clinical follow-up and response to therapy, 11 episodes of bacterial pneumonia and five cases of nonbacterial lung disease were established. The PSB Gram stain confirmed lower respiratory sampling in all cases. The PSB cultures indicated respiratory pathogens in 9/11 (82%) cases of pneumonia, with greater than 10(3) colony-forming units (cfu)/ml in all but two specimens. All patients with pneumonia responded to specific antibiotics. All patients with nonbacterial disorders had PSB cultures of less than 10(3) CFU/ml, and their pulmonary processes improved without antibiotic therapy. The procedure was well tolerated, although two patients had transient bronchospasm or apnea. Experience with the nasotracheal PSB is limited, but the procedure appears to be a reliable and relatively safe alternative diagnostic method in selected patients with suspected bacterial pneumonia. Quantitative cultures are necessary to improve its diagnostic accuracy.

Adult↗
PubMed1988

Enzyme-linked immunoabsorbent assays in the detection of Chlamydia trachomatis: how valid are they?

Two enzyme-linked immunoabsorbent assays (Chlamydiazyme, Abbott Laboratories, North Chicago, IL, and IDEIA, Boots-CellTech Diagnostics Inc., East Hanover, NJ) specific for the detection of Chlamydia trachomatis antigen were used to assess 451 cervical specimens. All specimens obtained from the subjects were also simultaneously cultured for Chlamydia. Both assays identified 90.9% (20/22) of the culture positive cases. Chlamydiazyme identified two and IDEIA three additional specimens as positive. Of these additional positive tests, one of two Chlamydiazyme and three of three IDEIA specimens were confirmed as positive by the direct fluorescent antibody technique (MicroTrak, Syva Co., Palo Alto, CA). Given the inexpense, availability, ease of performance, high sensitivity (91%), and specificity (99%) of these tests, both should become valuable tools to objectively assess women at risk for this common sexually transmitted disease.

Antigens, Bacterial↗
PubMed1987

Microbial contamination of contact lens care systems.

We examined the contact lens care systems of 100 asymptomatic patients who used hard or soft contact lenses for correction of refractive errors for the presence of bacteria, fungi, Acanthamoeba, and endotoxin. Of 100 patients, 52 had contaminated contact lens care systems. Sixteen of 126 bottles (13%) of commercial contact lens care solutions were contaminated. Contaminated commercial solutions were opened and used for a longer period of time than uncontaminated solutions. Contamination was not found in bottles of preserved commercial solutions that were opened and used for less than 21 days. All 12 bottles of homemade saline were contaminated with bacteria, and Acanthamoeba was isolated from two of these bottles. Pseudomonas was found in the care systems of 12 patients. Bacillus species, which form spores resistant to heat, were found in the care systems of seven patients. Endotoxin, which is also resistant to heat, was detected in nine of 35 care systems (26%) tested. Potential pathogens were isolated from the conjunctiva of six patients.

Adolescent↗
PubMed1987

Determination of estrogen and androgen receptors in Trichomonas vaginalis and the effects of antihormones.

Trichomonas vaginalis, a common genital pathogen, was found to possess both specific estrogen and specific androgen receptors. These 4.3 S macromolecules were proteinaceous in nature. Both metronidazole-resistant and metronidazole-sensitive strains possessed both types of sex hormone-binding proteins. The estrogen receptor binding was competitively inhibited by the antiestrogen tamoxifen citrate, and the androgen binding was competitively inhibited by the antiandrogen cyoctol. The presence of these specific receptors may allow the use of hormonal and antihormonal manipulation in the treatment of infections caused by these organisms.

Androgen Antagonists↗