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M Altwegg

Publications and source records attributed to M Altwegg.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Detection of Bartonella (Rochalimaea) henselae/B. quintana by polymerase chain reaction (PCR)].

Bartonella (Rochalimaea) henselae and/or B. quintana are the causative agents of a variety of infections such as trench fever, bacillary angiomatosis, septicemia, peliosis hepatis and endocarditis. Recently, B. henselae has been identified as a major cause of cat scratch disease. Diagnosis of such infections is based on clinical information, histopathology, culture and serology. However, none of these methods alone is sufficiently sensitive or specific. We have used the PCR to search for DNA specific for B. henselae/B. quintana in 33 clinical samples and in 6 controls. In comparison with clinical data and histopathology, PCR was extremely specific (100%) and reasonably sensitive (61%). Possible explanations for the limited sensitivity of PCR are discussed. We conclude that PCR provides a useful adjunct for the diagnosis of infections caused by B. henselae and B. quintana.

Bartonella Infections↗
PubMed1996

Stool cultures for Shigella spp: improved specificity by using MacConkey agar with xylose.

A total of 678 stool specimens were cultured on four different agars: on xylose-lysine-desoxycholate agar (XLD), MacConkey agar (Mac), MacConkey agar supplemented with xylose (Mac-X), and Hektoen enteric agar (HE). Isolation rates for shigellae were 77% on HE, 86% on Mac and Mac-X, and 91% on XLD. The specificities of the media were 61% for Mac, 75% for HE, and 78% for XLD and Mac-X. After overnight incubation, Mac-X is much easier to read than XLD, which requires incubation for at least 22 hours. Based on these results and also on the practical aspect that incubation for 22-21 hours does not fit well in our schedule, we now use Mac-X whenever shigellae need to be looked for (i.e. mainly patients with recent travel to tropical countries). As compared to our previous procedure the workload in the laboratory could be reduced by about 20%.

Agar↗
PubMed1996

[Acute gonarthritis--application of current diagnostic study methods exemplified by a case report].

The evaluation of acute inflammatory knee arthritis deserves special emphasis, because immediate benefit may result from identification and treatment of the underlying disease. The diagnostic approach to and the differential diagnosis of an acute knee arthritis are presented. By means of a case report, the use of the needle arthroscopy and the polymerase chain reaction (PCR) method for analysis of synovial fluid and synovial tissue in the diagnosis and evaluation of treatment of Lyme disease is described. The significance of this approach in diagnostic and therapeutic procedures has yet to be defined.

Arthritis, Infectious↗
PubMed1995

Identification of DNA gyrase A mutations in ciprofloxacin-resistant isolates of Salmonella typhimurium from men and cattle in Germany.

Six multiply resistant isolates of Salmonella typhimurium var. copenhagen with high-level resistance to fluoroquinolones (e.g., MIC of ciprofloxacin: 32 micrograms/ml) were isolated from human patients (n = 3) and from cattle (n = 3). The isolates were examined by complementation tests using a set of broad-host-range plasmids, which carry either the gyrA+ or the gyrB+ genes or a combination of both from Escherichia coli K-12. The results indicated a combination of gyrA and gyrB mutations in all isolates. Subsequent direct sequencing of PCR-generated internal DNA fragments of gyrA revealed an identical double mutation in all six isolates (Ser-83-->Ala and Asp-87-->Asn). In addition, the results of phenotypic (i.e., phagetype, biotype, serotype) and genotypic characterization [i.e., ribotyping and polymerase chain reaction fingerprinting (PCR-fingerprinting)] were identical for all six isolates and were distinguishable from a quinolone-susceptible strain of the same serovar and an unrelated isolate of S. typhimurium. These data indicate the clonal identity of the fluoroquinolone-resistant strains of S. typhimurium isolated from men and cattle in Germany.

Adolescent↗
PubMed1995

Evaluation of five new plating media for isolation of Salmonella species.

A three-phase study was conducted to compare Hektoen enteric agar (HE), Rambach agar (Ra), SM-ID medium (SM), xylose-lysine-Tergitol 4 agar (XLT4), novobiocin-brilliant green-glycerol-lactose agar (NBGL), and modified semisolid Rappaport-Vassiliadis medium (MSRV) for the recovery of nontyphoid salmonellae from stool specimens. After evaluation of the first two phases, which resulted in the elimination of Ra, SM, and NBGL, 593 consecutive stool samples were investigated by plating them directly and after tetrathionate enrichment at 37 degrees C on HE, XLT4, and MSRV. A total of 82 Salmonella-positive stool specimens were detected (positivity rate, 13.8%). Sensitivities for direct plating and after tetrathionate enrichment were 32.9 and 86.6%, respectively, for XLT4, 63.4 and 100.0%, respectively, for MSRV, and 34.1 and 79.3%, respectively, for HE. Specificities (percentage of morphologically suspicious colonies that were indeed salmonellae) were 100.0 and 99.8%, respectively, for XLT4, 99.0 and 98.8%, respectively, for MSRV, and 67.9 and 75.0%, respectively, for HE. The use of MSRV instead of HE increased the isolation rate of salmonellae by 26.2% (65 versus 82 strains isolated from HE and MSRV, respectively). We conclude that MSRV is the most sensitive medium tested and is a very specific medium for the isolation of nontyphoid salmonellae from stool specimens. However, its semisolid nature is a disadvantage and requires careful handling in the laboratory, especially when salmonellae are present. XLT4 had a sensitivity comparable to that of HE and a nearly 100% specificity and can be regarded as an alternative for the isolation of nontyphoid salmonellae from stool samples.

Agar↗
PubMed1995

Molecular analysis of Salmonella enteritidis by pulsed-field gel electrophoresis and ribotyping.

A total of 61 isolates of Salmonella enteritidis were analyzed by the techniques of pulsed-field gel electrophoresis (PFGE) and ribotyping. Twenty-three of the isolates were from Zurich, Switzerland, and 38 isolates were from the University Hospital, Kuala Lumpur, Malaysia. Five of the Malaysian isolates were hospital-related outbreak strains and were shown to be indistinguishable by PFGE analysis following digestion with three different restriction endonucleases, XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3'). The PFGE pattern of an isolate from a suspected carrier staff nurse was found to be identical to those of the hospital outbreak isolates. These isolates were also indistinguishable by ribotyping with SmaI and SphI. The same single PFGE pattern was also detected in 29 of 32 sporadic isolates of S. enteritidis. Four closely related ribotypes were detected among these 29 isolates. Similarly, outbreak-related strains from Switzerland showed close genetic identity by PFGE and ribotyping. Strains obtained from poultry showed more variations in their PFGE patterns and ribotypes, although the patterns were still closely related. In addition, SphI ribotypes A and D among the Swiss strains correlated with phage types 4 and 8, respectively. No correlation of phage types with PFGE pattern was noted. Both PFGE and ribotyping indicate that the S. enteritidis strains circulating in Malaysia and Switzerland are very similar and may be clonally related. Comparison of the PFGE patterns with the ribotypes for 23 Swiss and 16 Malaysian isolates showed that there was a 69% concordance in the grouping of isolates. We conclude that the close genetic similarity observed between epidemiologically unrelated and outbreak-related isolates of S. enteritidis suggests that both PFGE and ribotyping are of limited value in the epidemiological analysis of these particular isolates, possibly because of the highly clonal nature of pathogenic strains of S. enteritidis.

Animals↗
PubMed1995

Analysis of restriction fragment length polymorphism and ribotyping of multiresistant Stenotrophomonas maltophilia isolated from persisting lung infection in a cystic fibrosis patient.

A cystic fibrosis patient was infected by Stenotrophomonas maltophilia over at least 15 months. The bacteria became increasingly resistant to antimicrobial agents. Determination of restriction fragment length polymorphism and ribotyping showed that resistance was due to changes in that S. maltophilia rather than to infection by another strain.

Adult↗
PubMed1994

Detection of shigellae, enteroinvasive and enterotoxigenic Escherichia coli using the polymerase chain reaction (PCR) in patients returning from tropical countries.

We have used the polymerase chain reaction (PCR) to detect shigellae, EIEC and ETEC in stool specimens of diarrhoeic patients returning from tropical countries. As compared to culture (7.1% positive specimens), which recognizes only Shigella strains, PCR performed on bacterial growth from directly inoculated MacConkey agar plates and directed against virulence-associated genes present in both Shigella and EIEC was positive in 19.8% of the samples. We assumed that these additional positive results represent true rather than false positive samples because identical results for each single specimen were obtained using two different PCR systems and because positive results (culture as well as PCR) were exclusively found in patients with recent travel but not in those who acquired diarrhoea in a developed country where these organisms are not endemic. PCR detecting LT- and ST-specific sequences was positive in 18.5% of the patients with recent travel. Again no positive cases were identified in controls. Combining PCR and culture results, at least one bacterial pathogen was found in more than 50% of the patients with recent travel. We conclude that PCR is superior to culture methods for the detection of Shigella, EIEC and ETEC in travel-associated diarrhoea.

Aeromonas↗
PubMed1994

Molecular epidemiology of Salmonella enteritidis.

Sixteen strains of Salmonella enteritidis isolated in 1991 from 13 unrelated poultry-associated sources, 7 strains from 2 community outbreaks, and 18 human sporadic isolates were investigated by phage typing, analysis of rRNA gene restriction patterns (ribotyping) and plasmid profiles. Four different phage types and 10 SphI patterns were found, whereas plasmids were identical in all but 4 isolates. Only one ribotype (RT A) occurred among both human and avian strains. This particular ribotype was also responsible for the two outbreaks investigated, suggesting that such strains may be of special significance for the increase of S. enteritidis infections.

Animals↗
PubMed1994

Development of resistance to macrolide antibiotics in an AIDS patient treated with clarithromycin for Campylobacter jejuni diarrhea.

In an AIDS patient with diarrhea, identical isolates of Campylobacter jejuni susceptible and, later, resistant to macrolide antibiotics were isolated from feces before and after treatment with clarithromycin. Results of rRNA gene restriction analysis and serotyping suggest that development of resistance rather than simultaneous infection with a susceptible and a resistant strain was responsible for this phenomenon. This is the first report of in vivo development of resistance by Campylobacter jejuni in a patient treated with a macrolide for Campylobacter jejuni infection.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Nontoxigenic Corynebacterium diphtheriae isolated from intravenous drug users.

During a prospective study 117 intravenous drug users were screened for infection with Corynebacterium diphtheriae. Nontoxigenic C. diphtheriae was found in 5 of 132 throat swab specimens and in 5 of 28 skin ulcer specimens taken from July 1991 to April 1992. When phenotypic and molecular typing methods were used, these 10 strains were shown to belong to a single clone. During the same period no strain was isolated from 200 controls. Clinical manifestations of infection were not clearly attributable to C. diphtheriae--no typical membranous pharyngitis was present. The presence of a single clone among homeless intravenous drug users in Zurich indicates the presence of C. diphtheriae in parts of the population with poor standards of hygiene and low socioeconomic status.

Adult↗
PubMed1994

Turicella otitidis gen. nov., sp. nov., a coryneform bacterium isolated from patients with otitis media.

The partial 16S rRNA gene sequences of some coryneform bacteria isolated from middle-ear fluids from patients with otitis media were determined. A comparative analysis performed with rRNA sequences of other high-G + C-content gram-positive bacteria showed that the coryneform bacteria isolated from otitis media patients were only remotely related to members of previously described genera. On the basis of the results of the phylogenetic analysis and previously published biochemical and chemotaxonomic data, we propose that the strains isolated from middle-ear infections should be classified in a new genus, Turicella, as Turicella otitidis gen. nov., sp. nov. The type strain of T. otitidis is strain DSM 8821.

Actinomycetales↗
PubMed1994

Comparison of two methods for detecting intrathecal synthesis of Borrelia burgdorferi-specific antibodies and PCR for diagnosis of Lyme neuroborreliosis.

An indirect immunofluorescence assay (IFA), a commercial capture enzyme-linked immunosorbent assay (ELISA), and PCR were compared for the diagnosis of Lyme neuroborreliosis in 16 individuals. Borrelia burgdorferi-specific intrathecal immunoglobulin G was found in 10 of 16 patients by IFA and in 8 of 12 patients by capture ELISA. PCRs performed on cerebrospinal fluid samples stored at -70 degrees C were positive for one of eight children and one of four adults with intrathecal antibody production and negative for all four adults without intrathecal antibody production. For two children with facial palsy following erythema chronicum migrans, neither IFA nor capture ELISA detected specific intrathecal antibodies and PCR was also negative. We conclude that both clinical manifestations and laboratory parameters are important for the diagnosis of Lyme neuroborreliosis.

Adolescent↗
PubMed1993

[Effect of ciprofloxacin therapy in duration of bacterial excretion in acute salmonella gastroenteritis].

In view of the increasing incidence of non-typhoid salmonellosis, the effect of early treatment with ciprofloxacin on the permanent elimination of salmonella was evaluated. In a prospective study, 14 patients with non-typhoid salmonellosis were treated with 2 x 500 mg/d ciprofloxacin for 10 days within 5 days of onset of symptoms. Relapse occurred in 4/14 (29%) patients 2-3 weeks after termination of therapy. Using sero- and ribotyping, relapse was confirmed and reinfection ruled out in 4/4 patients. Furthermore, ribotyping suggested double infection in one patient. Development of resistance to ciprofloxacin was not observed. We conclude that the use of antimicrobial chemotherapy to treat non-institutional salmonellosis in immunocompetent patients cannot generally be recommended but must be considered carefully in each case. Indications for ciprofloxacin therapy in the treatment of non-typhoid salmonellosis are discussed.

Adult↗
PubMed1993

Characterization of Listeria strains from a foodborne listeriosis outbreak by rDNA gene restriction patterns compared to four other typing methods.

The rDNA gene restriction patterns of 134 isolates of Listeria species were determined with pKK3535--a pBR322 derived plasmid containing an Escherichia coli rRNA operon--used as a probe following digestion of chromosomal DNA by EcoRI endonuclease. Nineteen reference and type strains representing all species and serotypes of Listeria showed 17 distinct ribotypes. One hundred and fifteen wild strains of Listeria monocytogenes were ribotyped and the results were compared to those of serotyping, phage typing, multilocus enzyme electrophoresis (MEE) and restriction endonuclease analysis (REA). Ninety-six Listeria monocytogenes serotype 4b wild strains displayed six distinct ribotypes (I-VI), 72% (69/96) of them clustering in two very close rDNA patterns (I and II) of eight and nine bands, respectively. The same 96 strains displayed six REA patterns and eight MEE electrotypes. Among the 96 Listeria monocytogenes 4b isolates, the 34 epidemic strains defined by phage typing and by epidemiological data all belonged to one ribotype (ribotype I) representing 56% of the strains belonging to this ribotype. These same 34 epidemic strains were also grouped by REA and MEE typing in a unique profile (REA-A) and MEE electrotype (ET 1). Twenty-two Listeria monocytogenes strains of serogroup 1/2 analyzed by rDNA typing showed nine distinct ribotypes. For the 96 Listeria monocytogenes 4b strains studied, the discriminatory index was highest for phage typing and for any combination including phage typing. Ribotyping appears to be a well reproducible molecular typing method and could be a useful complement to other typing methods for the epidemiological study of listeriosis.

Bacterial Typing Techniques↗