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I Kühn

Publications and source records attributed to I Kühn.

At least 19 recordsLinked to original sources
PubMed2005

Changes of viability and composition of the Escherichia coli flora in faecal samples during long time storage.

Long-time storage of faecal samples is necessary for investigations of intestinal microfloras. The aim of the present study was to evaluate how the viability and the composition of the Escherichia coli flora are affected in faecal samples during different storage conditions. Four fresh faecal samples (two from calves and two from infants) were divided into sub-samples and stored in four different ways: with and without addition of glycerol broth at -20 degrees C and at -70 degrees C. The viability and the phenotypic diversity of the E. coli flora in the sub-samples were evaluated after repeated thawings and after storage during 1 year. The samples stored for 1 year without thawing were also kept at room temperature for 5 days and subsequently analysed. According to phenotyping (PhP analysis) of 32 isolates per sample on day 0, all four samples contained two dominating strains of E. coli each, and between one and eight less common strains. Samples that were stored at -70 degrees C in glycerol broth showed equal or even higher bacterial numbers as the original samples, even after repeated thawings, whereas samples stored at -20 degrees C showed a considerably lower survival rate, also with addition of glycerol. Sub-samples containing glycerol broth that were kept at room temperature after storage for 1 year showed a clear increase in the number of viable cells as well as in diversity. The diversities in each sub-sample showed a tendency to decrease after several thawings as well as after storage. Generally, the E. coli populations in samples stored at -20 degrees C were less similar to the population of the original sample than that in samples stored at -70 degrees C. Samples that had been mixed with glycerol broth had an E. coli flora more similar to that in the original sample than those without glycerol broth. Furthermore, the sub-samples that were kept at room temperature after storage for 1 year generally were more similar to the original samples than if they were processed directly. We conclude that for long time storage of faecal samples, storage at -70 degrees C is preferable. If samples have to be thawed repeatedly, addition of glycerol is preferable both for samples stored at -70 degrees C and for samples stored at -20 degrees C. Our data also have indicated that when E. coli isolates from faecal samples are selected for, e.g. analysis of virulence factors, it is necessary to pick several isolates per sample in order to obtain at least one isolate representing the dominating strain(s).

Animals↗
PubMed2005

Diversity among 2481 Escherichia coli from women with community-acquired lower urinary tract infections in 17 countries.

OBJECTIVES: In the recently published ECO.SENS survey, the antimicrobial susceptibility of Escherichia coli from urinary tract infections in women in 16 European countries and Canada was investigated. This study reports the diversity among these E. coli. METHODS: The 2481 E. coli, typed with the PhenePlate (PhP) System utilizing the dynamics and end result of 11 biochemical reactions in a microplate system, were clustered and the Simpson's index of diversity calculated. RESULTS: Seventy-four Common PhP Types (CT) comprising 2067 isolates and 414 Single Types (Si) were identified. Of these, 916 isolates (37%) belonged to one of the four most frequent CT (arbitrarily numbered CT48, 10, 26 and 20). CT48 with 400 isolates and 11 different susceptibility patterns, was widely disseminated across Europe and Canada and was the most frequent type in 13 countries and the second most frequent in the remaining four countries. Sixty-four per cent of the E. coli were susceptible to all eight investigated antimicrobials (CT48: 73%, CT10: 77%, CT26: 62% and CT20: 37%). Forty-six different susceptibility patterns were seen, the three most common being isolated resistance to ampicillin, resistance to ampicillin and trimethoprim, and isolated resistance to trimethoprim. Multiresistance, here defined as resistance to four or more of the investigated antibiotics, was distributed among E. coli belonging to several PhP types. CONCLUSIONS: There was no obvious correlation between the phenotypes identified with the PhP System and the susceptibility pattern. The data did not indicate clonal dissemination within or between countries as a major reason for differences in antimicrobial resistance rates.

Adult↗
PubMed2005

Phene Plate (PhP) biochemical fingerprinting. A screening method for epidemiological typing of enterococcal isolates.

Pulsed-field gel electrophoresis (PFGE) is currently considered the gold standard for genotyping of enterococci. However, PFGE is both expensive and time-consuming. The purpose of this study was to investigate whether the PhP system can be used as a reliable clinical screening method for detection of genetically related isolates of enterococci. If so, it should be possible to minimize the number of isolates subjected to PFGE typing, which would save time and money. Ninety-nine clinical enterococcal isolates were analysed by PhP (similarity levels 0.90-0.975) and PFGE (similarity levels < or =3 and < or =6 bands) and all possible pairs of isolates were cross-classified as matched or mismatched. We found that the probability that a pair of isolates (A and B) belonging to the same type according to PhP also belong to the same cluster according to PFGE, i.e. p(A(PFGE)=B(PFGE) * A(PhP)=B(PhP)), and the probability that a pair of isolates of different types according to PhP also belong to different clusters according to PFGE, i.e. p(A(PFGE) not equalB(PFGE) * A(PhP) not equalB(PhP)), was relatively high for E. faecalis (0.86 and 0.96, respectively), but was lower for E. faecium (0.51 and 0.77, respectively). The concordance which shows the probability that PhP and PFGE agree on match or mismatch was 86%-93% for E. faecalis and 54%-66% for E. faecium, which indicates that the PhP method may be useful for epidemiological typing of E. faecalis in the current settings but not for E. faecium.

Bacterial Typing Techniques↗
PubMed2004

Studies on calf diarrhoea in Mozambique: prevalence of bacterial pathogens.

The prevalence of diarrhoea in calves was investigated in 8 dairy farms in Mozambique at 4 occasions during 2 consecutive years. A total of 1241 calves up to 6 months of age were reared in the farms, and 63 (5%) of them had signs of diarrhoea. Two farms had an overall higher prevalence (13% and 21%) of diarrhoea. Faecal samples were collected from all diarrhoeal calves (n = 63) and from 330 healthy calves and analysed for Salmonella species, Campylobacter jejuni and enterotoxigenic Escherichia coli (ETEC). Salmonella spp. was isolated in only 2% of all calves. Campylobacter was isolated in 11% of all calves, irrespective of health condition, and was more frequent (25%) in one of the 2 diarrhoeal farms (p = 0.001). 80% of the isolates were identified as C. jejuni. No ETEC strains were detected among the 55 tested strains from diarrhoeal calves, but 22/55 (40%) strains from diarrhoeal calves and 14/88 (16%) strains from healthy calves carried the K99 adhesin (p = 0.001). 6,757 E. coli isolates were typed with a biochemical fingerprinting method (the PhenePlate) giving the same E. coli diversity in healthy and diarrhoeal calves. Thus it was concluded: i) the overall prevalence of diarrhoea was low, but 2 farms had a higher prevalence that could be due to an outbreak situation, ii) Salmonella did not seem to be associated with diarrhoea, iii) Campylobacter jejuni was common at one of the 2 diarrhoeal farms and iv) ETEC strains were not found, but K99 antigen was more prevalent in E. coli strains from diarrhoeal calves than from healthy, as well as more prevalent in one diarrhoeal farm.

Animals↗
PubMed2003

Comparison of enterococcal populations related to urban and hospital wastewater in various climatic and geographic European regions.

AIMS: Scarce knowledge about the distribution of enterococci species in wastewaters limits any statement on their reliability as faecal indicators or the implications of antibiotic resistance transmission by these organisms through the water cycle. Enterococci have been involved in nosocomial infections and the spreading of antibiotic resistance through the food chain. The species distribution of enterococci and the presence of resistant strains to vancomycin and erythromycin were analysed in more than 400 raw and treated urban wastewaters, surface waters receiving these treated wastewaters and hospital wastewaters from three European countries. METHODS AND RESULTS: A total of 9296 strains were isolated and biochemically phenotyped. The species identification was based on the comparison of biochemical profiles with those of more than 20000 enterococci isolates from an international study. The prevalence of enterococcal isolates resistant to erythromycin (ERE) and vancomycin (VRE) was also analysed. ERE strains were present in a high proportion in all the studied samples. VRE strains were also isolated in all studied countries despite the time elapsed since the use of antimicrobial glycopeptides in animal production was banned in the European Union. CONCLUSIONS: Enterococcus faecalis and Ent. faecium were the most abundant species in all the studied wastewaters. All the studied wastewaters demonstrated high diversity and similar population structure and composition. ERE and VRE isolates were detected in most of the wastewaters. SIGNIFICANCE AND IMPACT OF THE STUDY: Urban and hospital wastewaters are useful targets for the evaluation of the prevalence of ERE and VRE isolates in the environment. It appears that these bacteria could pass through wastewater treatment plants and be transferred to surface waters.

Cities↗
PubMed2003

Clonality among ampicillin-resistant Enterococcus faecium isolates in Sweden and relationship with ciprofloxacin resistance.

OBJECTIVE: To investigate clonal relationships in a nationwide sample of human Enterococcus faecium isolates. METHODS: Biochemical fingerprinting (PhP (PhenePlate) typing) was used to compare 180 fecal ampicillin-resistant E. faecium (ARE) isolates with 169 matched fecal ampicillin-susceptible E. faecium (ASE) isolates from patients in 23 hospitals, collected in 1998, and to study 39 fecal ARE isolates from non-hospitalized individuals collected in 1998, and five ARE and 29 ASE isolates from the early 1990s. Representative ARE and ASE isolates were subjected to pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA and sequencing of the regions encoding the fluoroquinolone targets of the enzymes GyrA and ParC. RESULTS: Both PhP and PFGE results showed a higher homogeneity among ARE than among ASE isolates (P < 0.001). One PhP type (FMSE1) comprised 73% of the hospital ARE isolates (53% of ARE isolates from non-hospitalized individuals, and four of five ARE isolates from the early 1990s), but only 1% of the ASE isolates. PFGE of the hospital E. faecium isolates revealed that 23 of the 25 ARE isolates and one of the 22 ASE isolates were of one dominating type. High-level resistance to ciprofloxacin (MIC > 16 mg/L) was present in 91% of ARE isolates, whereas only low-level resistance (MIC 4-16 mg/L; 35% of isolates) was found among ASE isolates. One mutation in parC (codon 80) and one of two mutations in gyrA (codons 83 or 87) were detected in all ARE isolates tested with high-level ciprofloxacin resistance, but were lacking in ARE and ASE isolates with low-level ciprofloxacin resistance. CONCLUSION: Most ARE isolates in Sweden were clonally related. High-level ciprofloxacin resistance was found in ARE isolates of PhP type FMSE1 as well as in other PhP types, but never in ASE isolates.

Ampicillin↗
PubMed2000

Deposition and disease: a moss monitoring project as an approach to ascertaining potential connections.

In the years 1995 and 1996 the atmospheric deposition of elements in the EuroRegion Neisse (ERN) was determined in a biomonitoring project using mosses. The mosses Pleurozium schreberi and Polytrichum formosum were chosen as biomonitors because of their wide distribution in the area studied. The moss samples were analysed by ICP-MS and ICP-OES for their concentrations of 37 chemical elements. The results were shown in the form of maps. The data from the moss monitoring project served as a basis for determining those elements in the deposited material that promote the occurrence of disease. This was done by correlating the figures for the various diseases with the appropriate element concentrations in the mosses. Indications were found that a connection exists between the thallium content of mosses and the occurrence of cardiovascular disease and between Ce, Fe, Ga and Ge levels in the mosses and the incidence of diseases of the respiratory system.

Adolescent↗
PubMed2000

Epidemiology and ecology of enterococci, with special reference to antibiotic resistant strains, in animals, humans and the environment. Example of an ongoing project within the European research programme.

The objectives of the present study are to generate knowledge of the ecology and epidemiology of enterococci in the food chain by studying the following: (1) the population structure (in measures of abundance, number of vancomycin resistant strains, antibiotic resistance patterns, diversity, and stability) among enterococcal populations in different geographical regions and in different links of the food chain (2) possible transmission of strains through the food chain and between hospital environments and the food chain (3) the association between vancomycin resistance and individual strains of enterococci and (4) the diversity of the drug resistance genes in enterococci. So far, 1578 samples have been collected from different countries within the EU (Sweden, Denmark, UK and Spain), and from different habitats (pig farms, carcasses in slaughter houses, soil, manure, water, sewage, and humans). Total and vancomycin resistant enterococcal populations in each sample have been enumerated and more than 12000 isolates have been characterised by phenotyping. Representative isolates are further species identified and characterised by genotyping and MIC determination and from antibiotic resistant isolates the resistance genes are characterised.

Animals↗
PubMed2000

Clonal groups of enteropathogenic Escherichia coli isolated in case-control studies of diarrhoea in Bangladesh.

Recent case-control studies in Bangladesh showed a high prevalence of enteropathogenic Escherichia coli (EPEC) strains (identified by DNA probes for virulence genes) associated with childhood diarrhoea. However, the clonal status of these strains is not known. A total of 94 EPEC isolates from 80 children with diarrhoea and 14 healthy matched controls isolated during 1991-1992 and 1993-1994 was characterised by serogrouping, enterobacterial repetitive intergenic consensus sequence PCR, and by a biochemical fingerprinting method (the phene plate or PhP system). Twelve O serogroups were found with O114 (n = 19) and O127 (n = 23) being the dominant serogroups. Most strains of O114 belonged to the same PhP/PCR types. Strains of O127 contained 16 that produced cytolethal distending toxin (CDT) and seven that did not; both were found among patients as well as controls. Results of PCR and PhP typing showed that CDT-positive strains belonged to the same clonal group and were related to one of the two PhP/PCR types of CDT-negative O127 strains. Thirty-one EPEC strains were O non-typable and 21 strains belonged to other less prevalent serogroups. These strains belonged to diverse PhP/PCR types and did not show any similarity to the strains of two major serogroups, O114 and O127. The results suggest that two clonal groups of EPEC strains are predominantly associated with childhood diarrhoea in Bangladesh.

Bacterial Typing Techniques↗
PubMed1999

[Polyglandular autoimmune syndrome type II: epidemiology and forms of manifestation].

BACKGROUND AND OBJECTIVE: Polyglandular autoimmune syndrome (PAS), is characterized by the coexistence of several autoimmune diseases, affecting predominantly the endocrine glands. The juvenile form (PAS type I) is distinguished from the adult type II in which autoimmune thyroiditis, adrenal cortical insufficiency and diabetes mellitus type I predominate. The connections between epidemiological, clinical and immunological aspects were analysed and described in this study of patients with PAS type II. PATIENTS AND METHODS: Among a total patient population of over 15,000 seen in our endocrinological university policlinic from 1992 through 1996, the clinical data of all 151 patients with PAS type II were analysed retrospectively. RESULTS: Of the 151 patients with PAS 37 were male (aged 16-74 years, median 42 years) and 114 female (aged 16-84 years; median 46 years), a prevalence of 1:100, 92 patients (61%) had diabetes mellitus type I (78% males, 55% females; p = 0.013), 50 (33%) had hyperthyroidism (32% and 33%; difference not significant), 49 had Hashimoto's thyroiditis (14% and 39%; p = 0.005) and 28 (18.5% had Addison's disease (14% males, 20% females; n.s.). Vitiligo was less common, occurring in 30 (20%), alopecia in 9 (6%), pernicious anaemia in 5 (5%) and hypogonadism in 8 (5%). The most common combination was diabetes type I with thyroiditis (33%), the time between manifestations of each disease being highly variable, diabetes was the first manifestation in half the cases. Partial cell antibodies were present in 62 patients (54%), and 52% had positive thyroid-associated antibodies without manifest signs of thyroid disease. CONCLUSION: PAS occurs relatively often among patients of an endocrinological centre, with a 3:1 female to male ratio. Because there is usually a long interval between the onset of the various endocrine diseases, regular monitoring of patients with an endocrine autoimmune disease is indicated, specific tests to be performed if additional immune diseases are suspected.

Addison Disease↗
PubMed1999

Clonality of Vibrio anguillarum strains isolated from fish from the Scandinavian countries, Sweden, Finland and Denmark.

In order to investigate whether outbreaks of vibriosis in the Baltic region were caused by the spread of certain pathogenic clones, 291 Vibrio anguillarum isolates from Finland (n = 156), Sweden (n = 88) and Denmark (n = 47) were studied with respect to serogroup, ribotype, plasmid content, and biochemical phenotypes as expressed with the PhenePlate (PhP) typing system. For comparison, 54 V. anguillarum serogroup O1 from other countries worldwide were included. Most isolates from Finland, Sweden and Denmark belonged to serogroup O1 (255), followed by O2 (30). Four Finnish isolates cross-reacted strongly with antisera against two new serogroups VaNT2 and VaNT4, whereas two strains were non-typeable. The serogroup O1 isolates displayed ten different ribotype patterns, whereas the other strains were considerably more diverse with respect to ribotypes. Most of the O1 isolates carried the 67 kb virulence plasmid and a group of Finnish isolates, in addition, carried an 86 kb plasmid. Additional plasmids with molecular weights of 63, 76, 135 or 260-290 kb were found in single O1 isolates. With few exceptions, strains of serogroup O2 either had no plasmids or carried one or two small plasmids. PhenePlate typing revealed considerable diversity within the species, serogroup O1 being the most homogeneous. A few PhP types were dominant, whereas other types were observed only in one to four isolates. The prevalence of the different types changed significantly from one year to another but in Finland, one clonal lineage became increasingly important from 1992 (20% of isolates) to 1996 (80%). Remaining clones were mostly restricted to specific geographic areas. By cluster analysis, it was demonstrated that most of the isolates from Finland, Sweden and Denmark belonged to two clusters, and most of the strains from Southern Europe fell into two other, distinct clusters. Most isolates from the UK, North America, Chile and Tasmania grouped together in a distinct cluster. For the typing of V. anguillarum, O-serotyping should be the primary method. For isolates belonging to serogroups other than O1, plasmid profiling in combination with ribotyping gives a very good discrimination between strains, whereas for serogroup O1, another method is required. It is concluded that PhP typing is a tool that provides a good discrimination between O1 isolates.

Animals↗
PubMed1999

Occurrence, diversity, and pathogenicity of halophilic Vibrio spp. and non-O1 Vibrio cholerae from estuarine waters along the Italian Adriatic coast.

The occurrence, diversity, and pathogenicity of Vibrio spp. were investigated in two estuaries along the Italian Adriatic coast. Vibrio alginolyticus was the predominant species, followed by Vibrio parahaemolyticus, non-O1 Vibrio cholerae, and Vibrio vulnificus. By using a biochemical fingerprinting method, all isolates were grouped into nine phenotypes with similarity levels of 75 to 97.5%. The production of toxins capable of causing cytoskeleton-dependent changes was detected in a large number of Vibrio strains. These findings indicate a significant presence of potentially pathogenic Vibrio strains along the Adriatic coast.

Animals↗
PubMed1998

Occurrence, diversity and pathogenicity of mesophilic Aeromonas in estuarine waters of the Italian coast of the Adriatic Sea.

A total of 208 strains of Aeromonas were isolated by monthly sampling from two estuaries (one provided with, and the other devoid of a waste-water treatment system) on the Italian coast of the Adriatic sea between September 1994 and August 1995. Biotyping at the species level allowed the identification of 96 strains (46%) as Aer. caviae, 46 (22%) as Aer. sobria, 33 (16%) as Aer. hydrophila and 25 (12%) as Aer. veronii. Eight strains (4%) were regarded as unnamed aeromonads. Aeromonas caviae was the most prevalent species in water with a high degree of pollution, while Aer. hydrophila strains were more commonly isolated from cleaner water. Aeromonas sobria and Aer. veronii were equally distributed in both estuaries. There was no correlation between temperature and numbers of aeromonads in either estuary. Using a biochemical fingerprinting method, strains were divided into similarity groups (PhP-types) based on their biochemical phenotypes. Several different PhP-types were found in each estuary, yielding a high diversity for these strains. However, some identical PhP-types were also found in both estuaries and at different times of the year, indicating that certain Aeromonas strains can survive more widely varying physico-chemical conditions. The production of toxins capable of causing cytoskeletal-dependent changes in the morphology of Chinese hamster ovary (CHO) cells was detected in 14 strains and appeared to be dependent on the season.

Aeromonas↗
PubMed1997

Evaluation of the Phene Plate generalized microplate for metabolic fingerprinting and for measuring fermentative capacity of mixed bacterial populations.

The Phene Plate (PhP) generalized microplate for metabolic fingerprinting and for measuring the fermentative capacity of intestinal bacteria was evaluated. Twelve bacterial species, representing those commonly found in the intestine of humans and animals were employed. Mixtures of bacteria were inoculated in duplicate onto the PhP microplates. Anaerobic conditions were achieved by either incubating the plates under nitrogen atmosphere or by covering the microplates with mineral oil before incubation. Different metabolic fingerprints based on the pattern of substrate utilization were obtained for each bacterial mixture. Metabolic responses of bacterial samples were similar under both anaerobic conditions although the rate of carbohydrate utilization was higher in plates covered with mineral oil. A fermentative capacity value based on the number and the degree of fermented carbohydrates was established for each mixture which differed as the composition of the mixture changed but in general it was higher in samples with more bacterial species. The PhP generalized microplate may thus be used for studying the functional status and metabolic potential of intestinal floras.

Anaerobiosis↗
PubMed1997

Metabolic fingerprinting and fermentative capacity of the intestinal flora of pigs during pre- and post-weaning periods.

We used the Phene Plate generalized microplates to investigate the metabolic activities of faecal flora of pigs during pre- and post-weaning periods. Weekly samples were collected from four sows and their litters (four piglets from each) during 5 months. The metabolic fingerprints obtained from faecal floras of sows and their litters in the first sampling occasion was very similar, suggesting that sows were the initial source of flora for piglets. This similarity, however, was lost in week 2 and piglets developed new types of flora which, although similar among the litter-mates, differed from those of the sows. The metabolic fingerprints of pigs' floras during the post-weaning period also differed from those of the suckling period. On day 70 pigs were transferred to a fattening stable. The faecal flora of the animals during this period was unstable in each individual and differed among litter-mates. A pattern of successive changes was observed in the fermentative capacity (FC) of pigs' floras reaching the highest value before weaning (day 34). An overall decrease in the FC value of faecal floras was observed as a consequence of dietary shifts from milk to solid food to high energy fattening diet. The mean FC value of pig floras on the first sampling occasion (mean +/- S.D. = 0.41 +/- 0.02) was significantly higher than that obtained in the last sampling occasion (day 145) (0.31 +/- 0.04) (P < 0.001). Faecal floras of sows also had lower FC values (0.25 +/- 0.01) than those of piglets suggesting that loss of FC by the faecal flora of young pigs will continue as they age.

Animal Feed↗
PubMed1997

Diversity, persistence, and virulence of Aeromonas strains isolated from drinking water distribution systems in Sweden.

The Aeromonas populations in 13 Swedish drinking water distribution systems, representing different treatments, were investigated. From each system, water samples were collected four times during the period from May to September 1994 from raw water and water after treatment and at two to five sites within the distribution system. In total, 220 water samples were collected. From samples containing presumptive Aeromonas, up to 32 colonies were analyzed by the PhenePlate Aeromonas (PhP-AE) system, which is a highly discriminating biochemical fingerprinting method. Selected isolates from different phenotypes (PhP types) were further identified by the API 20 NE system and by gas-liquid chromatography analysis of fatty acid methyl esters (FAMEs). Selected isolates were also assayed for their potential to produce hemolysin and cytotoxin and for their ability to adhere to human intestinal cells. In total, 117 water samples (53%) contained presumptive Aeromonas which numbered up to 10(6) CFU/100 ml in raw water and up to 750 CFU/100 ml in tap water. Among the 2,117 isolates that were subjected to typing by the PhP-AE system, more than 300 distinct PhP types were found, of which the majority occurred only sporadically. Raw (surface) water samples usually contained many different PhP types, showing high diversity indices (Di) (median Di = 0.95). The Aeromonas populations in samples collected from within the distribution systems were less diverse (median Di = 0.58) and were often dominated by one major PhP type that was found on several sampling occasions. Seventeen such major PhP types could be found and were represented in 1,037 isolates (49%). Identification by API 20 NE and FAME analysis revealed that most of the major PhP types were Aeromonas hydrophila or belonged to unidentified Aeromonas species. Hemolysin and cytotoxin production was observed in most major PhP types (representing 87 and 54% of the assayed isolates, respectively), and adherence was found in 89% of the isolates that produced cytotoxin. Thus, the data presented here show that although raw water may contain very diverse Aeromonas populations, the populations seemed to be remarkably stable within the studied water distribution systems, and that some potentially pathogenic Aeromonas strains could persist for several months in drinking water.

Aeromonas↗
PubMed1997

Characterization of Aeromonas spp. isolated from humans with diarrhea, from healthy controls, and from surface water in Bangladesh.

Aeromonas isolates from patients with diarrhea in Bangladesh (n = 69), from healthy controls (n = 11), and from surface water (n = 40) were analyzed with respect to their hybridization groups (HGs) by the aid of fatty acid methyl ester (FAME) characterization and DNA fingerprinting by AFLP, biochemical phenotypes (Phe-nePlate [PhP] types), and the production of hemolysin and cytotoxin. The aim of the investigation was to find out whether certain strains carrying virulence factors predominated among patient isolates. According to FAME and/or AFLP analysis, most human isolates were allocated to DNA HGs 4 (Aeromonas caviae) and 1 (A. hydrophila). Most environmental strains were allocated to HG8 (A. veronii biogroup sobria) and HG4 (A. caviae), and only one was of HG1. According to PhP typing, the diversity among patient isolates was lower than that among other strains, and two dominating PhP types (types BD-1 and BD-2) were identified in 29 and 30% of the patient isolates, respectively. PhP type BD-1 was also common among the environmental isolates, whereas PhP type BD-2 was only identified in two of the other isolates. Twenty-five of 26 isolates belonging to HG1 were of the same PhP type (BD-2), whereas isolates of other common HGs were more diverse according to their PhP types. Hemolytic and cytotoxin-producing strains occurred more frequently among the environmental isolates than among patient isolates. However, the hemolytic and cytotoxic activities among human isolates was strongly correlated to the HG1/BD-2 type, which, in addition, showed high cytotoxin titers (median values, 1/512 compared to 1/128 for cytotoxin-positive isolates belonging to other types). Thus, the HG1/BD-2 type may represent a pathogenic A. hydrophila type that is able to produce diarrhea in humans.

Aeromonas↗