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Biomedical subjects

G E Pfyffer

Publications and source records attributed to G E Pfyffer.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Extrapulmonary infections with Mycobacterium tuberculosis complex].

In a retrospective study we reviewed all records of patients with newly diagnosed Mycobacterium tuberculosis complex infection during the years 1990-1994. Of the 45 patients identified, 27 (60%) had only pulmonary tuberculosis and 18 (40%) had extrapulmonary tuberculosis with (5 patients, 11%) or without (13 patients, 18%) concomitant pulmonary infection. The extrapulmonary manifestations were as follows: miliary 5, joint 3, meningeal 2, pleural 2, kidney 1, peritoneal 1, bone 1, psoas 1, lymphatic 1, and anal 1. In the 18 patients with extrapulmonary tuberculosis the infection was due to Mycobacterium tuberculosis 14 times, Mycobacterium bovis twice, and Mycobacterium bovis BCG once.

Adult↗
PubMed1996

[Mycobacterium haemophilum infection in a patient with AIDS].

HISTORY AND FINDINGS: A 35-year-old HIV-infected man with a CD4 cell count of 100/microliter who had returned from a holiday in Spain presented with fever, chronic diarrhoea, cough, oral ulcers, subcutaneous nodules of about 1 cm in diameter and crusted skin ulcers of about 2 cm in diameter at his right arm, both wrists and buttocks. INVESTIGATIONS: Microscopic examination and culture of smears of a skin ulcer revealed acid-fast bacteria. Mycobacterial cultures of blood, sputum, urine and stool remained sterile. TREATMENT AND COURSE: Before the microorganisms were identified culturally, atypical mycobacteriosis was assumed and treatment with rifampicin, ethambutol, isoniazid and clarithromycin was started. Mycobacterium haemophilum was identified by using molecular biological techniques. Within 3 weeks the patient became afebrile and the skin ulcers healed completely. After a 7-week course, the treatment had to be stopped, and one month later painful subcutaneous nodules developed again at his arms and legs. A relapse of Mycobacterium haemophilum infection was confirmed by culture of a fine needle aspirate of a nodule. The same treatment was restarted and the nodules disappeared. CONCLUSIONS: Mycobacterium haemophilum, first identified in 1978, is an emerging pathogen in immunocompromised patients. Clinical manifestations usually are skin ulcers, subcutaneous nodules and subcutaneous abscesses, and less frequently, systemic infection. Treatment options of this life threatening disease have yet to be defined but therapeutic response to tuberculostatic combination therapy has been observed. Since Mycobacterium haemophilum is a fastidious organism, special laboratory methods are required for cultivation as well as for identification.

AIDS-Related Opportunistic Infections↗
PubMed1996

Isolation of Arthrobacter spp. from clinical specimens and description of Arthrobacter cumminsii sp. nov. and Arthrobacter woluwensis sp. nov.

Arthrobacter spp. are very widely distributed in the environment (e.g., soil) but have not been described as causing disease in humans. Over a 6-year period, two reference laboratories isolated or received 11 strains which were eventually identified as belonging to the genus Arthrobacter. These strains had been initially identified as Centers for Disease Control and Prevention coryneform group B-1 and B-3 bacteria (whitishgrayish colonies of 2 mm or greater in diameter after 24 h of incubation, respiratory metabolism, absent or weak acid production from sugars, and hydrolysis of gelatin). However, chemotaxonomic investigations revealed lysine as the diamino acid of the cell wall and the presence of branched cellular fatty acids (with anteiso-pentadecanoic acid predominating) which was compatible with an assignment of the 11 isolates to the genus Arthrobacter only. Peptidoglycan and 16S rRNA gene sequence analyses demonstrated that three of the strains studied were representatives of a new Arthrobacter species for which the name Arthrobacter cumminsii sp. nov. is proposed and that one other strain represented a second new Arthrobacter species for which the name Arthrobacter woluwensis sp. nov. is proposed. This report is the first on the isolation of Arthrobacter spp. from clinical specimens.

Arthrobacter↗
PubMed1996

Diagnostic performance of amplified Mycobacterium tuberculosis direct test with cerebrospinal fluid, other nonrespiratory, and respiratory specimens.

The Gen-Probe Amplified Mycobacterium tuberculosis Direct Test (MTD) was adapted to be used for cerebrospinal fluid (CSF) and a large variety of other nonrespiratory specimens. Standardized with artificially spiked dilution series of CSF, the modified MTD procedure consists of (i) increasing the amount of sample 10-fold, (ii) pretreating the specimen with a detergent, and (iii) increasing the amplification time from 2 to 3 h. Performance of MTD in a clinical mycobacteriology laboratory was tested over an extended period of time, involving a total of 322 nonrespiratory as well as 1,117 respiratory specimens from 998 patients. Results from MTD were compared with those from microscopy, culture, analysis of tuberculostearic acid by gas-liquid chromatography-mass spectrometry (CSF only), and the final clinical diagnosis. When MTD results were compared with resolved data, the sensitivity, specificity, and positive and negative predictive values for MTD were 93.1, 97.7, 90.0, and 98.5%, respectively, for nonrespiratory specimens and 86.6, 96.4, 76.8, and 98.1%, respectively, for respiratory specimens. Our data demonstrate that (i) MTD is a robust, highly sensitive and specific technique for the rapid detection of M. tuberculosis complex in all types of clinical specimens, (ii) there was no statistically significant difference (P > 0.005) in sensitivity and specificity for nonrespiratory compared with respiratory specimens, and (iii) repeating all MTDs which yield a result between 30,000 and 200,000 relative light units would help prevent a large number of false positives and, thus, enhance test specificity.

Adolescent↗
PubMed1996

Etiological agents of mycobacterioses in pet birds between 1986 and 1995.

Between May 1986 and June 1995, mycobacteriosis was diagnosed by histology and microscopy in 204 (3.8%) of 5,345 necropsied pet birds. The predominant macroscopic changes were enlargement of the liver and spleen and thickening of intestinal walls. Attempts to cultivate mycobacteria were made in 110 cases. Acid-fact bacilli grew in 66 specimens (60%) only. In 18 cases we failed to obtain subcultures. Therefore, species identification could be performed for only 48 isolates. Identification was carried out by conventional biochemical tests as well as by PCR-mediated sequencing of the 16S rRNA gene. The majority of the isolates were Mycobacterium genavense (34 isolates), followed by M. avium complex (8), M. fortuitum (2), M. tuberculosis (2), M. gordonae (1), and M. nonchromogenicum (1). The significance of M. genavense as a zoonotic agent remains to be determined.

Animals↗
PubMed1996

Isolation and characterization of a unique group of slowly growing mycobacteria: description of Mycobacterium lentiflavum sp. nov.

A distinct group of slowly growing mycobacteria was identified on the basis of growth characteristics, biochemical and lipid profiles, and nucleic acid analyses. The isolates showed growth at 22 to 37 degrees C, yellow pigmentation, and negative tests for Tween 80 hydrolysis, nicotinic acid, nitrate reductase, and urease; tests for arylsulfatase, pyrazinamidase, and heat-stable catalase were variable. Analysis of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography and high-performance liquid chromatography indicated a distinctive pattern which was unlike those of other species. Determination of the 16S rRNA gene sequence showed a unique sequence closely related to Mycobacterium simiae and M. genavense. On the basis of DNA homology studies, we suggest that these organisms are representatives of a novel species, for which the name M. lentiflavum sp. nov. is proposed.

Bacterial Typing Techniques↗
PubMed1996

Utility of PCR in diagnosing pulmonary tuberculosis.

At present, the rapid diagnosis of pulmonary tuberculosis rests with microscopy. However, this technique is insensitive and many cases of pulmonary tuberculosis cannot be initially confirmed. Nucleic acid amplification techniques are extremely sensitive, but when they are applied to tuberculosis diagnosis, they have given variable results. Investigators at six centers in Europe compared a standardized PCR system (Amplicor; Roche) against conventional culture methods. Defined clinical information was collected. Discrepant samples were retested, and inhibition assays and backup amplification with a separate primer pair were performed. Mycobacterium tuberculosis complex organisms were recovered from 654 (9.1%) of 7,194 samples and 293 (7.8%) of 3,738 patients. Four hundred fifty-two of the M. tuberculosis isolates from 204 patients were smear positive and culture positive. Among the culture-positive specimens, PCR had a sensitivity of 91.4% for smear-positive specimens and 60.9% for smear-negative specimens, with a specificity of 96.1%. Analysis of 254 PCR-positive, culture-negative specimens with discrepant results revealed that 130 were from patients with recently diagnosed tuberculosis and 94 represented a presumed laboratory error. Similar analysis of 118 PCR-negative, culture-positive specimens demonstrated that 27 discrepancies were due to presumed uneven aliquot distribution and 11 were due to presumed laboratory error; PCR inhibitors were detected in 8 specimens. Amplicor enables laboratories with little previous experience with nucleic acid amplification to perform PCR. Disease in more than 60% of the patients with tuberculosis with smear-negative, culture-positive specimens can be diagnosed at the time of admission, and potentially all patients with smear-positive specimens can immediately be confirmed as being infected with M. tuberculosis, leading to improved clinical management.

Bacteriological Techniques↗
PubMed1994

The new diagnostic mycobacteriology laboratory.

Recent surveys in the USA show that many mycobacteriology laboratories continue to use less-than-optimum culture and susceptibility testing methods. This seems to be true for European countries as well. The past few years have brought significant changes to the clinical tuberculosis laboratory. High-performance liquid chromatography and direct detection of acid-fast bacilli in clinical specimens aim at the same goal: increased sensitivity and specificity of the diagnostic approach and reduction of turnaround time. This review outlines a brief comparison between contemporary traditional methods and the latest developments in the direct detection of acid-fast bacilli. If patient care and public health are always considered paramount, regardless of admission time, hospital type, etc., the current concept of services has several shortcomings. One way to manage this situation is to sort and allocate specimens according to a system of priorities. There is a growing realization that no single method by itself is the best. To streamline the best choice for laboratory diagnosis, an additional dynamic acid-fast network is presented: 'Point-of-Care,' 'Fast Track,' and 'Specialty' laboratories. The physician interacts with all three types of laboratories, so ongoing communication between the physician and the laboratory is essential. Laboratorians must work together in the formation of this dynamic acid-fast network to improve service rendered for our patients.

Bacteriological Techniques↗
PubMed1994

Identification of coryneform and other gram-positive rods with several methods.

The identification of 202 isolates of aerobically growing Gram-positive rods from clinical material was attempted by using a combination of "traditional" morphological and biochemical tests (Hollis & Weaver (20)) plus patterns of cellular and metabolic fatty acids. This system served as the "gold standard" for three others, i.e. API Coryne (Rapid Coryne), MIDI TSBA and MIDI CLIN Aerobic. In addition, several growth, biochemical and susceptibility tests (growth on cystine-tellurite blood agar, DNase, hippurate and starch hydrolysis, methanethiol formation, API ZYM, CAMP reaction, susceptibility to O/129 and to six antimicrobials) were done in order to check their usefulness for the identification of this group of bacteria. Our system, with the help of chemotaxonomic tests (m-DAP and mycolic acids), was able to identify 154/202 (76%) of the isolates by species and an additional 41/202 (21%) by genus only; 7 (3%) could not be identified. The API Coryne system identified to species or genus level 140/195 isolates (72%). Corresponding figures for the MIDI TSBA and CLIN systems were 63/195 (32%) and 88/195 (45%); further details of species and genus identification are presented in the text. The main drawback of the commercial systems is the extent and probably the numerical depth of the data base. We recommend the use of our multisystem approach for the identification of Gram-positive rods until commercial systems are based on a broader and numerically more extensive data base. The additional tests did not prove species- or genus-specific.

Culture Media↗
PubMed1994

Direct detection of Mycobacterium tuberculosis complex in respiratory specimens by a target-amplified test system.

A total of 938 respiratory specimens (633 sputa, 249 bronchial and tracheal aspirates, and 56 bronchoalveolar lavages) from 589 patients were tested for direct detection of Mycobacterium tuberculosis complex by the Gen-Probe amplified Mycobacterium tuberculosis direct test (MTD), and the results were compared with those of the conventional methods of fluorescence microscopy and cultivation (solid and radiometric media). One series of specimens (n = 515) was decontaminated with N-acetyl-L-cysteine (NALC)-NaOH: the other one (n = 423) was decontaminated with sodium dodecyl (lauryl) sulfate (SDS)-NaOH. Of the specimens decontaminated with NALC, 39 were MTD and culture positive, 455 were MTD and culture negative, 18 were MTD positive and culture negative, and 3 were MTD negative and culture positive, indicating a sensitivity of 92.9% and a specificity of 96.2% for the MTD. Of the specimens decontaminated with SDS, 35 were MTD and culture positive, 372 were MTD and culture negative, 15 were MTD positive and culture negative, and 1 was MTD negative and culture positive, indicating a sensitivity of 97.2% and a specificity of 96.1% for the MTD. After resolution of discrepant results by review of the patients' clinical data, the sensitivity of the MTD was 93.9%, the specificity was 97.6%, the positive predictive value was 80.7%, and the negative predictive value was 99.3% for the NALC series; the corresponding values were 97.4, 96.9, 76.0, and 99.7%, respectively, for the SDS series. In conclusion, the MTD is a highly sensitive and specific technique for detecting M. tuberculosis complex within hours in both smear-positive and smear-negative respiratory specimens.

Adult↗
PubMed1994

Characteristics of CDC group 3 and group 5 coryneform bacteria isolated from clinical specimens and assignment to the genus Dermabacter.

Over a 1-year period, 11 isolates (including 5 from blood cultures) of the recently described CDC group 3 and group 5 coryneform bacteria were derived from clinical specimens and compared with reference strains. Biochemical characteristics indicated a very close relationship between CDC group 3 and group 5 coryneform bacteria. The ability of CDC group 3 and the inability of CDC group 5 coryneform bacteria to ferment xylose were the only reactions that were different for the two taxa. Chemotaxonomic features of the two groups included the presence of meso-diaminopimelic acid, a lack of mycolic acids, and the presence of predominantly branched cellular fatty acids, a combination found among gram-positive rods only in Brevibacterium spp., Brachybacterium faecium, and Dermabacter hominis. 16S rRNA gene sequence analysis revealed that CDC group 3 and group 5 coryneform bacteria are members of the genus Dermabacter, which to date has been isolated exclusively from human skin.

Actinomycetales↗
PubMed1993

[Tuberculosis: diagnosis and incidence of resistance 1991/92].

In the past few years new diagnostic strategies have considerably cut down the turnaround time for detection, identification and susceptibility testing of mycobacteria. Highly sensitive methods (e.g., gene probes, PCR, gas liquid chromatography/mass spectrometry) will further improve rapid and accurate laboratory testing. They which all aim at a direct detection of mycobacteria in clinical specimens. In a brief survey conducted by the NZM/IMM susceptibility data of M. tuberculosis isolates in Switzerland were obtained from 14 laboratories. As expected, the great majority of the strains exhibit full sensitivity against the primary antituberculous drugs. The patterns as well as the percentages of resistance for the period between January 1991 to June 1992 do not differ significantly from the results obtained in an earlier investigation.

Antitubercular Agents↗
PubMed1993

[Multiresistant tuberculosis in the Zurich Höhenklinik Wald from 1984 to 1992].

Out of a total of 386 patients with culture-proven tuberculosis, ten cases of multidrug-resistant tuberculosis were treated in a high altitude chest clinic in Switzerland between 1984 and 1992. Two patients, Swiss, were alcoholics, the other eight foreigners. None of the patients were HIV-positive. Both Swiss had primary INH resistance, then developed secondary INH/RMP resistance due to poor compliance. All patients were treated with at least two additional in-vitro-sensitive drugs as well as with INH. Five patients underwent resection of lung parenchyma. One of these patients has had three operations and remains the sole therapy failure. One patient died before an operation could be performed. All others are well. Possible reasons for multidrug-resistance and the management of the ten cases are discussed in accordance with the literature.

Adult↗
PubMed1993

[Disseminated tuberculosis with a multiresistant strain of Mycobacterium tuberculosis in an HIV-infected Swiss male].

Multidrug-resistant M. tuberculosis in HIV-infected people has not yet been reported in Switzerland, and there have been no nosocomial epidemics as they have recently occurred in the USA. We present the case of a 38-ear-old HIV-infected man who developed disseminated tuberculosis as AIDS-defining disease. Initially he was treated with isoniazid, pyrazinamide and rifampin. Due to the emergence of resistance to isoniazid and streptomycin, ethambutol was added for one month. Later the therapy was changed back to the initial three drugs. The patient responded well to this therapy, but five months later developed a relapse. In addition to the originally diagnosed double-drug resistance, a reduced susceptibility to rifampin appeared. Ethambutol, ciprofloxacin and amikacin were added to the original three-drug regimen. This resulted in rapid clinical improvement, although sputum cultures remained positive for M. tuberculosis two months later. This isolate was resistant to pyrazinamide. For that reason pyrazinamide was replaced by clofazimine. 14 months after diagnosis the patient died of hepatic failure. Because there was a delay in isolation of one week, 37 potentially exposed health care workers were tested by the Mantoux skin test. No conversions were observed. This case report demonstrates that tuberculosis in HIV-infected patients in Switzerland may be caused by multidrug-resistant M. tuberculosis. We propose that until the results of a susceptibility assay are known, a four-drug combination should be used initially in this patient group.

AIDS-Related Opportunistic Infections↗