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C Buchrieser

Publications and source records attributed to C Buchrieser.

At least 37 records · Page 2Linked to original sources
PubMed1997

Recent emergence of new variants of Yersinia pestis in Madagascar.

Yersinia pestis, the causative agent of plague, has been responsible for at least three pandemics. During the last pandemic, which started in Hong Kong in 1894, the microorganism colonized new, previously unscathed geographical areas where it has become well established. The aim of this longitudinal study was to investigate the genetic stability of Y. pestis strains introduced into a new environment just under a century ago and to follow the epidemiology of any new genetic variant detected. In the present study, 187 strains of Y. pestis isolated between 1939 and 1996 from different regions of Madagascar and responsible mainly for human cases of bubonic and pneumonic plague were studied. Our principal genotyping method was rRNA gene profiling (ribotyping), which has previously been shown to be an effective scheme for typing Y. pestis strains of different geographical origins. We report that all studied Y. pestis strains isolated in Madagascar before 1982 were of classical ribotype B, the ribotype attributed to the Y. pestis clone that spread around the world during the third pandemic. In 1982, 1983, and 1994, strains with new ribotypes, designated R, Q, and T, respectively, were isolated on the high-plateau region of the island. Analysis of other genotypic traits such as the NotI genomic restriction profiles and the EcoRV plasmid restriction profiles revealed that the new variants could also be distinguished by specific genomic and/or plasmid profiles. A follow-up of these new variants indicated that strains of ribotypes Q and R have become well established in their ecosystem and have a tendency to spread to new geographical areas and supplant the original classical strain.

Animals↗
PubMed1996

Pulsed-field gel electrophoresis and ribotype profiles of clinical and environmental Vibrio vulnificus isolates.

Vibrio vulnificus belongs to the autochthonous bacterial flora of warm estuarine waters. It can cause life-threatening extraintestinal disease in persons who have underlying illness and who consume raw shellfish or contact wounds with estuarine water. Currently, very little is known about genetic diversity within this species. In this report, we describe high-level variation in restriction fragment length polymorphism profiles among 53 clinical and 78 environmental isolates, as determined by pulsed-field gel electrophoresis. In contrast, ribotype profiles showed greater similarity. When combined ribotype profiles of clinical and environmental isolates were analyzed, four predominant clusters were observed. Interestingly, a low number (16%) of clinical isolates were found in cluster C, compared with clusters A, B, and D (range, 50 to 83%). In addition, 83% of all Hawaiian isolates were located in a single cluster, indicating a possible relationship between geography and genotype. We also report that spontaneous translucent colonial morphotypes were distinct by both restriction fragment length polymorphism and biochemical profiles, compared with opaque parent strains.

Bacterial Typing Techniques↗
PubMed1996

rpoS regulation of acid, heat, and salt tolerance in Escherichia coli O157:H7.

An rpoS mutant (rpoS::pRR10) of Escherichia coli O157:H7 ATCC 43895 was generated. Stationary-phase acid, heat, and salt tolerance was significantly reduced, and starvation-induced acid tolerance did not develop in the mutant. RpoS was also important for survival of E. coli O157:H7 in dry, fermented sausage.

Acids↗
PubMed1995

Multiple Vibrio vulnificus strains in oysters as demonstrated by clamped homogeneous electric field gel electrophoresis.

Clamped homogeneous electric field gel electrophoresis and a computer program for managing electrophoresis banding patterns (ELBAMAP) were used to analyze genomic DNA of 118 Vibrio vulnificus strains, isolated from three oysters by direct plating. Analysis with SfiI resulted in 60 restriction endonuclease digestion profiles (REDP), while analysis with SrfI produced 53 different REDP. Similarities between REDP ranged from 7 to 93%. Principal-component analysis showed that the strains were heterogeneous.

Animals↗
PubMed1995

Investigations related to the epidemic strain involved in the French listeriosis outbreak in 1992.

Two hundred seventy-nine cases of human listeriosis (92 pregnancy-related cases and 187 non-pregnancy-related cases) caused by a serovar 4b and phagovar 2389:2425:3274:2671:47:108:340 strain were identified in France between March and December 1992. Epidemiological investigations included a case-control study (not described here) and microbiological analyses of foods. Results of the case-control study and characterization of food isolates identified pork tongue in jelly, a ready-to-eat meat product, as the major vehicle of this outbreak, and to a lesser extent, delicatessen products contaminated secondarily during handling in food stores. As far as serotyping, phage typing, DNA macrorestriction pattern analysis (obtained by pulsed-field gel electrophoresis [PFGE]), and ribotyping are concerned, this epidemic strain is phenotypically and genomically closely related to strains responsible for major outbreaks of listeriosis previously observed in Europe and North America. The epidemic strain sensu stricto as defined by PFGE (2/1/3) displayed the same serovar, phagovar, ribovar, and ApaI and NotI PFGE patterns as the epidemic strains from outbreaks in Switzerland, California, and Denmark, but it consistently showed differences in the SmaI PFGE profile. This information greatly contributed to the identification of the major food vehicle (pork tongue in jelly) and further allowed exclusion of other foods (cheese) as possible sources of this major listeriosis epidemic.

Disease Outbreaks↗
PubMed1994

Clamped homogenous electric fields (CHEF) gel-electrophoresis of DNA restriction fragments for comparing genomic variations among strains of yersinia enterocolitica and Yersinia spp.

Yersinia enterocolitica gastroenteritis was first recognized in the early 1960s and has since been reported with increasing frequency. To determine if strains of Y. enterocolitica, within a restricted region isolated over 8 years (1985-1993), originated from a single or multiple clones, pulsed-field gel electrophoresis (PFGE) of large chromosomal DNA restriction fragments generated by XbaI or NotI was used. A total of 27 isolates of Y. enterocolitica were analyzed, 24 from Austria (Vienna and Graz) consisting of serogroups 0:3 (17 isolates), 0:9 (6 isolates), 0:5 (1 isolate); 2 from Germany of serogroups 0:3 and 0:9 (1 isolate each); 1 from the U.S.A. of serogroup 0:8. Genomic fingerprints of these strains were compared to those of 8 other Yersinia species to ascertain if their restriction endonuclease digestion profiles (REDP) were serogroup and/or species specific. The 27 Y. enterocolitica strains could be divided into 16 genomic varieties according to their restriction patterns with NotI and XbaI. PFGE was highly discriminatory as strains belonging to the same serogroup could be subdivided into different genomic groups. Furthermore, Y. enterocolitica strains isolated from the same region, over an 8 year period, belonged to a few closely related clones. The genomic fingerprints of Yersinia were found to be species and serogroup specific.

DNA Fingerprinting↗
PubMed1994

Molecular characterization of Yersinia enterocolitica by pulsed-field gel electrophoresis and hybridization of DNA fragments to ail and pYV probes.

Sixty strains of Yersinia enterocolitica from five serogroups (O:3; O:9; O:8; O:5; and O:5,27) and eight non-Y. enterocolitica strains, recovered from diverse sources (humans, animals, food, and the environment) in Europe, Argentina, and the United States, were examined by the pulsed-field gel electrophoresis (PFGE) technique of contour clamped homogeneous electric field electrophoresis (CHEF) by using NotI and XbaI as restriction enzymes. NotI and XbaI generated 36 and 33 restriction endonuclease digestion profiles (REDP), respectively. By combining the results of both enzymes, 42 unique genomic groups were differentiated. DNA fragments were transferred to nylon membranes and hybridized with digoxigenin-labelled oligonucleotide probes to the ail gene and virulence plasmid to determine hybridization patterns and the potential virulence of the strains. The strains were tested for the presence of the plasmid by PFGE-CHEF and phenotypic characteristics encoded for by the virulence plasmid. Thirty of the 60 Y. enterocolitica strains tested harbored the virulence plasmid. The specificity of the ail and pYV probes was 100% when tested with 68 Yersinia strains and 19 different non-Yersinia strains. Sixteen selected Y. enterocolitica strains were tested for their virulence by lethality in iron- and desferrioxamine-sensitized mice. No correlation between REDP and the virulence of the strains was observed. The observed REDP and the hybridization patterns were very homogeneous within a serogroup and independent of the source of isolation. In addition, PFGE-CHEF was shown to be valuable in identifying and confirming serogroups. Principal component analysis of Dice similarity indices from REDP was an excellent tool for determining genetic relatedness among strains.

Amidohydrolases↗
PubMed1993

An improved direct viable count for the enumeration of bacteria in milk.

The direct viable count (DVC), a microscopic method for the enumeration of viable bacteria, was modified by replacing nalidixic acid with ciprofloxacin. This modification made it possible to apply this method to a variety of Gram-negative and Gram-positive bacteria which was not previously possible. Of the four antibiotics tested (nalidixic acid, novobiocin, ciprofloxacin and mitomycin C), ciprofloxacin and mitomycin C were the only ones effective for use in the DVC with all of the bacteria tested. In addition, ciprofloxacin could be used at a single concentration (1 microgram/ml) while adjustments were necessary with the other antibiotics when examining bacteria from different genera and, in some instances, from different species. The use of ciprofloxacin in the DVC resulted in viable cells that had elongated by 5-11 times their original length. We conclude that the modified DVC will be useful in growth and survival studies of bacterial pathogens and spoilage organisms in milk and other foods.

Animals↗
PubMed1993

Characterization of Listeria strains isolated from soft cheese.

Three soft cheeses were exposed to quantitative analysis for listeria and found to contain a large number of listeria. Thirty-five of the listeria strains isolated from the three cheeses were characterized by use of biochemical tests, serotyping, phagetyping and DNA restriction enzyme analysis. Seven isolates were identified as Listeria innocua and 28 as Listeria monocytogenes. Two to four different clones of L. monocytogenes could be identified from each cheese. In contrast, only one clone could be detected among the L. innocua isolates. From an epidemiological point of view the findings of different clones of L. monocytogenes in the same cheese emphasize the need for typing several listeria isolates from one and the same food sample. It is concluded that the best overview of the population of the listeria strains is obtained after direct plating of the sample followed by enumeration, isolation and extensive typing.

Bacteriophage Typing↗
PubMed1993

Pulsed-field gel electrophoresis applied for comparing Listeria monocytogenes strains involved in outbreaks.

Recent food-borne outbreaks of human listeriosis as well as numerous sporadic cases have been mainly caused by Listeria monocytogenes serovar 4b strains. Thus, it was of interest to find out whether a certain clone or a certain few clones were responsible for these cases and especially for outbreaks. We used pulsed-field gel electrophoresis of large chromosomal DNA restriction fragments generated by ApaI, SmaI, or NotI to analyse 75 L. monocytogenes strains isolated during six major and eight smaller recent listeriosis outbreaks. These strains could be divided into 20 different genomic varieties. Thirteen of 14 strains isolated during major epidemics in Switzerland (1983-1987), the United States (California, 1985) and Denmark (1985-1987) demonstrated indistinguishable DNA restriction patterns. In contrast, strains responsible for the outbreaks in Canada (Nova Scotia, 1981), the United States (Massachusetts, 1983), France (Anjou, 1975-1976), New Zealand (1969), and Austria (1986) and some smaller outbreaks in France (1987, 1988, 1989) were each characterized by particular combinations of DNA restriction patterns. Seventy-seven percent of the tested strains could be classified into the previously described ApaI group A (Brosch et al. 1991), demonstrating a very close genomic relatedness. Because 49% of the epidemic strains selected for this study belonged to phagovar 2389/2425/3274/2671/47/108/340 or 2389/47/108/340, fifty-six additional strains of these phagovars, isolated from various origins, were also typed to determine whether differences in DNA restriction profiles between epidemic and randomly selected strains of the same phagovars could be pointed out. Variations in DNA patterns appeared more frequently within randomly selected strains than within epidemic strains.

Bacterial Typing Techniques↗
PubMed1992

[10 years foodborne listeriosis--an evaluation].

Foodborne listeriosis outbreaks, which occurred in the past 10 years, have raised new questions in listeriosis epidemiology. The renewed interest in listeriosis and Listeria monocytogenes has resulted in various efforts, which enormously enriched the knowledge about his relatively rare, but because of the high mortality rate, important infectious disease as well as about its causative agent. New data concerning epidemiology and therapy of human listeriosis as well as new experience with Listeria monocytogenes regarding virulence, typing, isolation, identification, occurrence in food and environment, behaviour towards disinfectants etc. have changed the view of human listeriosis prevention. The new aspects are summarized in this review.

Adult↗
PubMed1991

Use of pulsed field gel electrophoresis to compare large DNA-restriction fragments of Listeria monocytogenes strains belonging to serogroups 1/2 and 3.

Thirty-five Listeria monocytogenes strains belonging to serogroups 1/2 and 3 and isolated from various origins were characterized by whole cellular DNA restriction patterns using low-frequency cleavage enzymes and pulsed field gel electrophoresis. Seventeen restriction profiles were detected with ApaI, 18 with SmaI and 15 with NotI, the combination of these patterns allowing one to define at least 24 distinct groups within the 35 strains. The significant genomic diversity pointed out by this method can be of value in the epidemiological fingerprinting of L. monocytogenes.

Animals↗
PubMed1991

Use of pulsed field electrophoresis of DNA restriction fragments for comparing Listeria monocytogenes strains isolated from human infections and food in Austria.

Twenty-five Listeria monocytogenes strains of human and food origin were studied, using low-frequency-cleavage restriction endonucleases and pulsed field gel electrophoresis. Sixteen different restriction patterns were obtained using ApaI and SmaI. The human isolates showed profiles different from those of the food isolates, thus strongly suggesting that the two human infections selected for this study did not originate from the contaminated foodstuffs examined at the same time. This method allowed it to clearly distinguish between strains apparently similar [i.e. belonging to the same serovar and same origin (cheese samples from the same dairy plant)].

Animals↗
PubMed1989

On the drinking water situation on the Cape Verde Islands (Island of Santiago).

On the Cape Verde Islands drinking water investigations were made. The drinking water was tested in chemical and bacteriological respects as well as on amebas and rotaviruses. The isolated germs were investigated on their reaction against several antibiotics and chemotherapeutics by means of the agar diffusion test. The changing of drinking water quality from water-supply-places to the households was investigated as well. According to the fact, that only 10.6% of 207 public water supplies investigated show drinking water quality after ONORM, and that nearly 30% and 80.2% of them contained E. coli and coliforme germs respectively, the urgency of extensive sanitations of water supplies on the Cape Verde Islands is evident.

Amoeba↗
PubMed1989

A survey of leptospirological studies carried out on the Cape Verde Islands.

The authors subjected 611 human sera, 1295 sera of domestic and 211 sera of wild living animals from two islands of the Cape Verde archipelago to serological tests for leptospirosis. Among the human sera 7.2% reacted positively. Antibodies to L. bratislava of the serogroup Australis were most frequent (59.1% of all positive sera). Antibodies to L. icterohaemorrhagiae were found in 1.3% of the sera tested, to L. sejroe in 1.1%, to L. canicola in 0.7%, to L. pyrogenes in 0.3% and to L. pomona, L. bulgarica and L. grippotyphosa in 0.2% each. The existence of natural foci of leptospiroses could not be proved since tests of 211 wild-living mammals were all negative. The investigation of domestic animal sera showed a positivity of 3.1% with goats being positive most frequently (85% of all positive sera), followed by donkeys with 3.3% and cattle with 2.0%. Sera of dogs, sheep and pigs were all negative. The results indicate that anthropurgic foci exist on the Cape Verde Islands.

Animals↗
PubMed1988

Investigation of human stool samples from the Cape Verde Islands (district Santa Cruz/Santiago).

Based on the rate of occurrence of diseases associated with diarrhoea, stool samples were also investigated; parasitologically, using the MiFC-enrichment method for intestinal parasites; serologically, using ELISA for rotavirus and bacteriologically for Shigella and Salmonella on the Cape Verde Islands. 90% of the samples came from children aged between 6 and 14 years. Entamoeba histolytica, the causal agent of amoebic dysentery was demonstrated in 17.4%, Lamblia intestinalis in 28.7% and rotavirus in 14.5%.

Adolescent↗