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Biomedical subjects

F S Nolte

Publications and source records attributed to F S Nolte.

At least 37 records · Page 2Linked to original sources
PubMed1996

Necrotizing cerebritis in an allogeneic bone marrow transplant recipient due to Cladophialophora bantiana.

We describe a necrotizing cerebritis in an allogeneic bone marrow transplant recipient caused by the neurotropic, dematiaceous fungus Cladophialophora bantiana. The patient presented 7 months after bone marrow transplantation with fever and sudden onset of left-sided weakness, followed shortly by cranial nerve III and VI palsies. The patient had a lesion (3.0 by 2.0 by 2.0 cm) of the right midbrain with extension to the pons, the left brain stem, and the right superior and the middle cerebellar peduncles. The diagnosis was made by microscopic examination and culture of a brain biopsy.

Adult↗
PubMed1996

Vancomycin-resistant Aureobacterium species cellulitis and bacteremia in a patient with acute myelogenous leukemia.

A 39-year-old male with acute myelogenous leukemia and concomitant porphyria cutanea tarda was admitted to the hospital for consolidation chemotherapy of his leukemia. During his hospitalization, he developed cellulitis of the left hand and persistent bacteremia with a yellow-pigmented, nonfermenting coryneform bacterium that was identified as Aureobacterium sp. The portal of entry for the Aureobacterium infection was probably through the skin lesions due to porphyria cutanea tarda. The infection developed while the patient was receiving vancomycin prophylaxis, and the vancomycin MIC for the isolate was 32 micrograms/ml.

Adult↗
PubMed1995

Early detection of human cytomegalovirus viremia in bone marrow transplant recipients by DNA amplification.

Surveillance blood cultures for human cytomegalovirus (HCMV) are commonly used to identify the bone marrow transplant (BMT) recipients with the highest risk of serious HCMV disease and for whom early interventional ganciclovir therapy would be beneficial. We monitored 36 allogeneic BMT recipients weekly for the presence of HCMV in the blood from 0 to 100 days posttransplantation. Viable HCMV in leukocytes (WBC) was detected by shell vial and tube culture methods. HCMV DNA in WBC and plasma was detected by PCR and DNA hybridization using primers and a probe from the EcoRI fragment D region of HCMV AD169. A uracil-N-glycosylase-dUTP PCR protocol was used to prevent false-positive results due to amplicon carryover. Seventeen patients had multiple consecutive positive samples containing HCMV DNA in plasma or WBC. In 14 of 17 patients, HCMV was also detected by blood culture. HCMV DNA was detected sporadically in six patients, none of whom had positive cultures. One patient had HCMV viremia detected by WBC culture only. The remaining 12 patients had no positive PCR assays or blood cultures. For the patients with positive blood cultures, PCR detection of HCMV DNA in plasma preceded detection of HCMV in culture by a mean of 8 days and detection in WBC preceded detection in culture by 6 days. HCMV disease (interstitial pneumonia) was documented for two patients with viremia (blood culture and PCR positive) and one patient without viremia (blood culture and PCR negative). The earlier recognition of high-risk patients provided by detection of HCMV DNA in plasma or WBC may improve the efficacy of early interventional antiviral therapy.

Bone Marrow Transplantation↗
PubMed1995

Preclinical evaluation of AMPLICOR hepatitis C virus test for detection of hepatitis C virus RNA.

We compared a single-enzyme, combined reverse transcription-PCR (RT-PCR; AMPLICOR HCV Test; Roche Molecular Systems, Branchburg, N.J.) with an independent, two-enzyme, standard RT-PCR (SRT-PCR) assay for the detection of hepatitis C virus (HCV) RNA in serum and plasma. Test samples included a proficiency testing panel consisting of 10 undiluted plasma samples, three separate dilution series, and sera from 99 patients with chronic liver disease. The quantity of HCV RNA in each patient serum sample was determined by a branched DNA (bDNA) signal amplification assay (Quantiplex HCV-RNA assay; Chiron, Emeryville, Calif.). There was complete concordance between the results of the RT-PCR assays with the 10 undiluted plasma samples used for proficiency testing (3 positive and 7 negative samples). However, the analytical sensitivity of SRT-PCR was 4- to 10-fold greater than that of the AMPLICOR test in the dilution series. HCV RNA was detected in 44, 45, and 40 of the patient serum samples, by SRT-PCR, the AMPLICOR test, and the bDNA assay, respectively. There was 97% agreement between the results of the RT-PCR assays, with only three discrepancies. Review of the patients' medical records resolved all three discrepancies in favor of the AMPLICOR results (two false-negative SRT-PCR results and one false-positive SRT-PCR result). The quantity of HCV RNA in sera from five (11%) patients with viremia detected by AMPLICOR was below the bDNA assay cutoff (< 3.5 x 10(5) RNA equivalents per ml). AMPLICOR compared favorably with SRT-PCR, with key advantages of speed, ease of use, increased sample throughput, and protection against false-positive results because of amplicon carryover.

Adult↗
PubMed1995

Detection of penicillin-resistant Streptococcus pneumoniae with commercially available broth microdilution panels.

We compared penicillin MICs obtained with three different commercially available broth microdilution panels (MicroScan, Sensititre, and Pasco) with MICs obtained with reference microdilution panels for 20 well-characterized pneumococci with decreased susceptibilities to penicillin (7 resistant and 13 intermediate). All panels were supplemented with 2 to 5% lysed horse blood (LHB) prepared in-house. Additional supplements included fastidious inoculum broth (FIB) for MicroScan panels and commercially prepared LHB (Difco) for Pasco panels. The percentages of penicillin-resistant strains (MIC 2 micrograms/ml) detected by the different methods follow: MicroScan-FIB, 0; MicroScan-LHB 0; Pasco in-house LHB, 71; and Sensititre-LHB, 100. The percentages of intermediate strains (MIC = 0.1 to 1.0 micrograms/ml) detected by the different methods follow: MicroScan-FIB, 31; MicroScan-LHB 23; Pasco in-house LHB, 46; and Sensititre-LHB, 85. Difco LHB supplement failed to support the growth of 86% of the strains in the Pasco panels. Of the commercially available panels evaluated, only Sensititre, supplemented with LHB prepared in-house could reliably detect penicillin-resistant pneumococci.

Culture Media↗
PubMed1995

Laboratory diagnosis of tuberculosis: past, present, and future.

Resurgence of tuberculosis justifies extraordinary efforts to expedite TB diagnosis and susceptibility testing. This demands that laboratory support expand to a "second generation" of methods and procedures, including rapid availability of fluorochrome smears of concentrated specimens, faster techniques for detection (e.g., the BACTEC radiometric broth system and microcolony detection), quicker identification (e.g., high-pressure liquid chromatography, nonisotopic genetic probes), more rapid susceptibility testing methods (e.g., BACTEC), and reporting of these results as critical values. Guidelines have been established for turnaround time for results of smears, TB organism identification, and susceptibility testing to usual first-line drugs. A "third generation" of laboratory techniques soon will make testing not only more effective but also more efficient. These methods include direct testing of respiratory specimens through nonisotopic genetic probes as well as nucleic acid amplification techniques utilizing polymerase chain reaction (PCR) and other molecular procedures. These new procedures and protocols place heavy demands on laboratory test volume, technologist time and costs. For the healthcare system or clinical laboratory without the resources to deal with these new demands, referral of TB specimens represents a reasonable alternative, as long as transport is adequate to meet current CDC and other guidelines for turnaround time.

Bacteriological Techniques↗
PubMed1994

Isolation of hepatitis C virus RNA from serum for reverse transcription-PCR.

Standard multistep extraction and isolation of RNA for hepatitis C virus (HCV) reverse transcription (RT)-PCR are impractical for routine use in clinical laboratories. We compared three simple commercially available methods for RNA isolation (RNAzol B, TRISOLV, and ULTRASPEC; Biotecx Laboratories, Houston, Tex.) and a total nucleic acid isolation method (IsoQuick; MicroProbe Corp., Garden Grove, Calif.) for the recovery of HCV RNA from sera obtained from 12 viremic patients for RT-PCR. RNAzol B, TRISOLV, ULTRASPEC, and IsoQuick extraction methods detected 87.5, 79.2, 33.3, and 58.3% of the paired positive samples, respectively. The method used for isolation of RNA is an important concern when optimizing HCV RT-PCR.

Evaluation Studies as Topic↗
PubMed1994

Practical considerations in the laboratory diagnosis of bacterial enteric infections.

Diarrheal diseases caused by bacterial pathogens are important causes of morbidity in the United States, and considerable laboratory resources are spent to detect these enteric pathogens. This article reviews recent developments in the detection and identification of Campylobacter spp, enterohemorrhagic Escherichia coli, and Clostridium difficile, and outlines cost-effective strategies for use of stool cultures.

Bacterial Infections↗
PubMed1993

Evaluation of modified MicroScan screening tests for high-level aminoglycoside resistance in Enterococcus faecalis.

Enterococcus faecalis strains that are refractory to aminoglycoside-penicillin synergistic killing can be predicted by their ability to grow in high concentrations of aminoglycoside (2,000 mg/L) or by disk diffusion tests using high content aminoglycoside disks. Forty-eight well-characterized clinical isolates of E. faecalis were used to evaluate recently reformulated gentamicin and streptomycin synergy screening tests on both overnight and rapid MicroScan (MS) Pos MIC panels (Baxter, West Sacramento, CA). The results obtained with the MS screening tests were compared with those from modified agar disk diffusion results. Discrepancies were resolved by an in-house broth microdilution method. The MS overnight tests detected 25 of 25 (100%) gentamicin high-level resistant strains and 23 of 24 (96%) streptomycin high-level resistant strains. No false high level resistance was found with the MS overnight tests. The MS rapid tests detected 100% of the gentamicin and 100% of the streptomycin high-level resistant strains, but one isolate was falsely high-level resistant to gentamicin (96% specific). The reformulated MS synergy screening tests were acceptable alternatives to disk diffusion for detection of high level aminoglycoside resistance in E. faecalis.

Anti-Bacterial Agents↗
PubMed1993

Multicenter clinical evaluation of a continuous monitoring blood culture system using fluorescent-sensor technology (BACTEC 9240).

The BACTEC 9240 (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is a new continuous-monitoring blood culture system that uses internal, fluorescent-CO2 sensors. In a multicenter clinical trial, organism yield and times to detection with the prototype BACTEC 9240 system were compared with those of the BACTEC NR 660 system. Equal volumes of blood were inoculated into the bottles included in the study blood culture sets (aerobic and anaerobic 9240 and NR6A and NR7A bottles). A total of 9,391 aerobic and 8,951 anaerobic bottle pairs were inoculated with 9,801 blood specimens. A total of 587 clinically significant positive blood cultures and 415 cases of sepsis were studied. The standard 9240 aerobic bottle detected significantly more Staphylococcus aureus (P < 0.05), coagulase-negative staphylococci (P < 0.01), and total microorganisms (P < 0.001) than the NR6A bottle. The standard 9240 anaerobic bottle detected significantly more coagulase-negative staphylococci (P < 0.001), members of the family Enterobacteriaceae (P < 0.01), and total microorganisms (P < 0.001) than the NR7A bottle. A total of 420 positive cultures were detected in both systems; for 284, the time to detection was equivalent with both systems (within 12 h); for 123, the 9240 system was faster; and for 13, the NR 660 system was faster (P < 0.001). The average times to detection for the 9240 and the NR 660 systems were 20.2 and 27.5 h, respectively. Ninety-nine cultures were positive only in the 9240 system, and 68 cultures were positive only in the NR 660 system (P < 0.02). The 9240 system also detected significantly more episodes of bacteremia (P < 0.001). The false-positive rates for the 9240 and NR 660 systems were 2.2 and 2.3%, respectively. The false-negative rates for the two systems after 5 days of incubation did not differ significantly. The contamination rates for the 9240 and NR 660 systems were 1.9 and 1.5%, respectively (P < 0.05). In conclusion, the prototype 9240 system detected more clinically significant positive blood cultures and did so sooner than the NR 660 system, with the additional advantages of full automation, continuous monitoring, and noninvasive sampling.

Bacteremia↗
PubMed1993

Direct detection of Mycobacterium tuberculosis in sputum by polymerase chain reaction and DNA hybridization.

A polymerase chain reaction (PCR) assay for the rapid diagnosis of pulmonary tuberculosis was developed by using oligonucleotide primers to amplify a fragment of IS6110, an insertion sequence repeated multiple times in the chromosome of Mycobacterium tuberculosis. Sediment obtained from sputa processed by the N-acetyl-L-cysteine-NaOH method was suspended in a simple lysis buffer and was heated at 100 degrees C for 30 min prior to amplification. A dUTP-uracil N-glycosylase PCR protocol was used to prevent false-positive test results because of the carryover of products from previous amplification reactions. The 317-bp amplicon was detected by direct gel analysis and Southern blotting and then hybridization with a biotin-labeled internal probe. Hybrid molecules were detected by using a commercially available avidin-alkaline phosphatase-chemiluminescent substrate system (Tropix, Inc., Bedford, Mass.). The analytical sensitivity of the assay was 10 fg of purified mycobacterial DNA. The limits of detection by culture (Middlebrook 7H11 agar and Lowenstein-Jensen medium) and by PCR were equivalent in terminal dilution experiments for organism suspensions and positive sputa. An internal control was used to detect the presence of amplification inhibitors in each negative reaction mixture. DNA was purified from inhibitory specimens by phenol-chloroform extraction and ethanol precipitation. PCR results were compared with results of microscopy and conventional culture for the detection of M. tuberculosis in 313 sputum specimens. There were 124 specimens that were positive for M. tuberculosis by conventional methods and 113 (91%) that were positive by PCR. PCR detected 105 of 110 (95%) of the smear-positive and 8 of 14 (57%) of the smear-negative specimens. There were no false-positive results by PCR (specificity, 100%). This PCR assay innovations that make application of this new technology feasible in clinical microbiology laboratories.

Bacteriological Techniques↗
PubMed1991

An alternative strategy for infection control of anesthesia breathing circuits: a laboratory assessment of the Pall HME Filter.

Contaminated breathing systems have been responsible for nosocomial upper respiratory tract and pulmonary infections in patients undergoing general anesthesia. The current infection control guidelines for anesthesia breathing circuits require single-patient use or high-level disinfection of breathing tubes, y-connector, and reservoir bag. An alternative infection control strategy has been suggested that incorporates placement of a microbial filter downstream from the y-connector between the circuit and the patient. This laboratory study assessed the capacity of the Pall HME Filter as a bidirectional barrier to transmission of bacteria between the y-connector of an anesthesia circle breathing system and a test lung. The investigators modified a sterile circle system to allow aerosolization of a suspension of 10(9) Micrococcus luteus over 5 h into the inspiratory limb proximal to the y-connector or downstream from the filter into the test lung. Cultures indicated that the Pall HME Filter placed between the y-connector and the test lung completely prevented transmission of bacteria in both directions. The results of this study suggest that the Pall HME Filter could be used as an effective microbial barrier between the anesthesia circle breathing system and the patient as part of an alternative strategy for infection control.

Anesthesia, Closed-Circuit↗
PubMed1990

Enhanced detection of Candida in blood cultures with the BACTEC 460 system by use of the aerobic-hypertonic (8B) medium.

The blood culture records during the 6-year period 1984-9 were reviewed to compare the performance of the BACTEC aerobic (6B) and aerobic-hypertonic (8B) media for the recovery of Candida spp. and Torulopsis glabrata from blood. There were 137 positive blood culture sets that contained both a 6B and an 8B bottle. Sixty-eight different yeasts were recovered from 65 patients including 35 Candida albicans, 19 C. tropicalis, 6 C. parapsilosis, 4 C. krusei, 1 C. pseudotropicalis and 3 Torulopsis glabrata. The 8B medium detected 120 of the positive cultures (87.6%) and was the only positive medium in 35 (25.6%) sets, while the 6B medium detected 102 positive cultures (74.4%) and was the only positive medium in 17 (12.4%) sets (P less than 0.04). For those sets in which both bottles were positive, radiometric detection occurred first in the 8B bottle in 39 sets and first in the 6B bottle in 11 sets (P less than 0.001). The superior performance of the 8B bottle was not related to the administration of amphotericin B. Cultures of stock strains of C. albicans, C. tropicalis, and C. parapsilosis in 6B and 8B media with and without added blood confirmed the finding that 8B was substantially superior to 6B for the detection of candidaemia. It is concluded that an 8B bottle should be included in the blood culture set whenever candidaemia is suspected.

Aerobiosis↗
PubMed1990

Quantitative aspects of septicemia.

For years, quantitative blood cultures found only limited use as aids in the diagnosis and management of septic patients because the available methods were cumbersome, labor intensive, and practical only for relatively small volumes of blood. The development and subsequent commercial availability of lysis-centrifugation direct plating methods for blood cultures have addressed many of the shortcomings of the older methods. The lysis-centrifugation method has demonstrated good performance relative to broth-based blood culture methods. As a result, quantitative blood cultures have found widespread use in clinical microbiology laboratories. Most episodes of clinical significant bacteremia in adults are characterized by low numbers of bacteria per milliliter of blood. In children, the magnitude of bacteremia is generally much higher, with the highest numbers of bacteria found in the blood of septic neonates. The magnitude of bacteremia correlates with the severity of disease in children and with mortality rates in adults, but other factors play more important roles in determining the patient's outcome. Serial quantitative blood cultures have been used to monitor the in vivo efficacy of antibiotic therapy in patients with slowly resolving sepsis, such as disseminated Mycobacterium avium-M. intracellulare complex infections. Quantitative blood culture methods were used in early studies of bacterial endocarditis, and the results significantly contributed to our understanding of the pathophysiology of this disease. Comparison of paired quantitative blood cultures obtained from a peripheral vein and the central venous catheter has been used to help identify patients with catheter-related sepsis and is the only method that does not require removal of the catheter to establish the diagnosis. Quantitation of bacteria in the blood can also help distinguish contaminated from truly positive blood cultures; however, no quantitative criteria can invariably differentiate contamination from bacteremia.

Anti-Bacterial Agents↗
PubMed1990

Cord formation in BACTEC 7H12 medium for rapid, presumptive identification of Mycobacterium tuberculosis complex.

We evaluated cord formation in BACTEC 7H12 medium as a criterion for rapid identification of Mycobacterium tuberculosis complex. Kinyoun-stained smears, prepared from 270 radiometrically positive BACTEC 7H12 bottles, were examined independently by three observers. Smears from 93.2, 88.6, and 83.0% of the M. tuberculosis complex cultures were read as cord positive, and smears from 97.3, 97.8, and 99.5% of the mycobacteria other than M. tuberculosis cultures were read as cord negative by the three observers, respectively. There was 93.3% agreement between the observers. The presence of cords in BACTEC 7H12 medium can be a reliable criterion for rapid, presumptive identification of M. tuberculosis complex.

Cord Factors↗