Determination of sero- and biovariants of foreign and Soviet strains of Yersinia enterocolitica]

The results of the typing of the biochemical and serological variants of Yersinia enterocolitica strains from the USSR (10 strains) and other countries (32 strains) are presented. Most of these strains, belonging to biovars 1 and 5, could be determined with the use of the antigenic scheme which was proposed by Knapp only for biovars 2, 3 and 4. The strains isolated in Leningrad and in the Far East were found to belong to serovars 6,30; 7,8; 12,25 and 5B according to the scheme proposed by Wauters; of these, the last one corresponds to serovar IV in Knapp's scheme.     

Serovars of nonagglutinating vibrios isolated on the territory of the Uzbek SSR and their role in the development of acute intestinal diseases

As the result of the serotyping of 1,223 NAG vibrio strains isolated in the Uzbek SSR from the environment and 659 strains isolated from gastroenteritis patients and from vibriocarriers, the serovars of 563 strains (46%) and 420 strains (63%), respectively, were determined. The prevailing serovars were 08, 06, 09, 014, 05, 039, 041, 013, 019 among the strains isolated from the environment and 08, 041, 037, 05, 039, 024, 06 among the strains isolated from humans. The strains belonging to serovars 05, 06, 08, 024, 037, 039, 041 were isolated both from the environment and from humans. The possible role of these strains in the development of acute gastroenteritis and in the formation of vibriocarriership in humans is pointed out.     

Etiological structure of salmonellosis and the serotype passage of salmonellae isolated in separate regions of the USSR in 1980-1982

At the period of 1980-1982 the isolation of salmonellae belonging to 394 serovars was registered in the USSR. Of these, 116 Salmonella serovars were registered in the USSR for the first time. 12 dominating serovars constituted 83.1% of salmonellae isolated from humans, 99% of salmonellae isolated from animals and 70% of all salmonellae isolated from different environmental objects. S. typhimurium was the predominant serovar, found to determine 50% of cases of Salmonella infection. The isolation rate of S. infantis and S. virchow was shown to increase. The existence of definite ecological relationships between infective agents isolated from different sources was established.     

Agricultural animals as a source of yersiniosis

The role of agricultural animals as the sources of infection was studied. 8 Yersinia strains were isolated from 83 samples taken from cattle. Yersinia were isolated from feces, udder washings and milk. In the examination of 63 samples obtained from sheep the infective agent was isolated from feces in 6 cases. 6 Yersinia strains were isolated from 92 fecal samples taken from pigs. Y. enterocolitica were isolated from sick animals. The isolated strains were classified with serovars 03, 058, 08 and 09. In the foci of animal infection thus revealed antibodies to various Yersinia strains were detected in the blood sera of the animal-tending personnel, which indicates the professional character of the spread of this infection among humans. The infection is probably transferred by the contact and alimentary routes.     

Serovars of Vibrio parahaemolyticus

Seashore water samples collected along the coastline in Bulgaria and Rumania contained in large numbers OK serovars of V. parahaemolyticus; some of these had been isolated repeatedly over an extended time period: 01 K32, 03 K30, 03 K48, 04 K37, 04 K53, 05 K17, 05 K30. The serovar 05 K17 was virtually present in all water samples and was also isolated from a case of purulent ear infection in a child from Burgas. In contrast, strains recovered from Asian and African coastal water had different K antigens and were never identified in Europe. Two strains of V. parahaemolyticus (serovars 05 K15 and 07 K10) had positive swarming growth resembling that of V. alginolyticus. The first of these was Kanagawa-positive and was isolated from a case of severe diarrhea in Brazzaville. Vibrio parahaemolyticus isolates came from marine or brackish water specimens collected on sand banks, 3 strains were recovered from marine or brackish water in Africa. Vibrio harveyi, a sucrose-negative species important from differential diagnostic aspects, has been isolated from seashore water samples collected on coarse-sand or pebbly beaches.     

The gene identification of bacterial species and serovariants by the polymerase chain reaction with universal oligonucleotides: the reidentification of earlier isolated strains of Yersinia pseudotuberculosis]

Genetic analysis of 19 standard strains belonging to 6 Yersinia species (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica, Y. kirstensenii, Y. frederiksenii, Y. intermedia) revealed that gene typing by the method of polymerase chain reaction (PCR) with the use of universal primers permitted the identification of species in bacterial cultures by PCR patterns and the determination of Y. pseudotuberculosis serovars within 4 hours. By this method 23 Y. pseudotuberculosis strains (serovar 1), earlier isolated in different regions of the USSR from humans and rodents, were studied. The study showed that out of 14 strains of human origin only two strains could actually be classified with serovar 1, while the remaining strains were reidentified as belonging to serovar 5. Among 9 strains isolated from rodents those of serovar 1 prevailed (8 strains). The authors suppose that strains of serovar 5 cause outbreaks and sporadic cases of pseudotuberculosis, occurring considerably more often than it is commonly believed in the USSR.     

Interrelation of the enterotoxigenic properties and the antigenic structure of Escherichia

The enzymatic signs and serological characteristics of Escherichia enterotoxigenic strains isolated from patients with acute intestinal diseases and from healthy persons were studied. The cultures were subdivided into 24 enzymatic variants and classified with 48 serogroups and 61 serovars. The enterotoxigenic properties of the strains were compared with their serological characteristics and enzymatic signs. The strains, isolated from different persons and classified with the same serovar, belonged to the same variant with respect to the type of enterotoxin they produced (only thermostable enterotoxin, only thermolabile enterotoxin, or both), were similar in the degree of their toxigenicity and belonged, as a rule, to the same enzymatic variant. The data on the presence of manifest interrelation between the enteropathogenicity of Escherichia and their structure, as well as on the stability of the enterotoxigenic properties of these organisms, indicate that in acute intestinal diseases the determination of Escherichia enterotoxigenic strains can be carried out by common bacteriological techniques with the use of specific agglutinating sera.     

Unusual serovar of the causative agent of Flexner's dysentery. I. Its distribution and biochemical properties

The data on the circulation of some S. flexneri strains in the USSR are presented. The antigenic structure of these strains (type antigen 4 and group antigens 7, 8) is not characteristic of known serological subvariants 4a, 4b or var. X. The time course of changes in their spreading on certain base territories controlled by the All-Union Shigellosis Center in 1980-1983 is shown. The biochemical characteristics of S. flexneri strains IV:7,8 under study, isolated in the USSR and abroad (Czechoslovakia, London) from humans, from a monkey and from the environment, are given. Similarities in the biochemical reactions of these strains with respect to indole, rhamnose, saccharose, maltose, arabinose and raffinose have been revealed. The strains isolated in the USSR have shown differences in the spectra of their resistance to antibiotics, depending on their territorial origin.     

Study of the properties of E. coli of serological group 03 isolated in acute intestinal diseases]

The authors studied the properties of 115 strains of E. coli of serological group 03 isolated from 49 children and adults with acute intestinal disturbances. The majority of the children (82.9%) were aged under one year. Results of the study of the antigenic structure and biochemical properties permitted to differentiate the strains isolated into 3 serological types, with the prevalence of strains of type O3 : K2 (L) : H2 (78.3%), and 8 biochemical variants. The majority of the strains possessed hemolytic properties. Strains of serological group O3 were isolated repeatedly from the patients during the sickness, whereas none were revealed in examination of 132 healthy children and adults. The data obtained permitted to consider these microbes to be possible causative agents of intestinal coliinfection, and to refer them to the enteropathogenic category.     

Potential virulence-associated properties of<Emphasis Type="Italic">Plesiomonas shigelloides</Emphasis> strains

Serotyping and some potential virulence-associated markers were investigated in Plesiomonas shigelloides strains isolated from humans, animals and aquatic environments. Surface properties of these strains were evaluated using Congo red binding, salt-aggregation test, bacterial adherence to xylene and motility. Production of pancreatic elastase, proteinase (consistent with subtilisin Carlsberg), triacylglycerol lipase, histidine decarboxylase and beta-hemolysin was also determined. In addition, detection of signal molecules such as C4-C8 unsubstituted N-acylhomoserine lactones (AHLs) was performed. The serological typing of the P. shigelloides strains showed that the isolates belonged to 13 different serovars. The majority of the strains were hydrophobic and motile. The strains produced low levels of elastase, proteinase and histidine decarboxylase whereas triacylglycerol lipase activity was relatively high. Only 23.3 % of the strains produced hemolysin. The AHLs signal molecules were not detected. P. shigelloides strains were able to produce a variety of potential virulence markers which may be involved in the pathogenesis of Plesiomonas-associated infections.     

Molecular evidence of <Emphasis Type="Italic">Plesiomonas shigelloides</Emphasis> as a possible zoonotic agent

The most frequently used method for establishing epidemiological relationships between Plesiomonas shigelloides strains is O:H serotyping. However, a number of strains are not serotypeable and isolates from diverse sources can display the same serovar. Moreover, since the zoonotic nature of Plesiomonas has been suggested and this hypothesis is based on the identical serovars found in animals and humans, we intend to use four DNA-based techniques: random amplified polymorphic DNA-PCR, enterobacterial repetitive intergenic consensus-PCR, repetitive extragenic palindromic-PCR, and pulsed field gel electrophoresis in order to screen 24 strains belonging to nine O:H serovars isolated from humans, animals, and the environment. In general, P. shigelloides showed a high genetic heterogeneity. Three pairs of strains, each containing a human and an animal isolate, displayed similar genotypes. This is the first report that provides molecular evidence that P. shigelloides may be zoonotic.     

Risk factors and transmission routes of the causative agents of campylobacteriosis in commercial poultry plants]

The study, carried out in two regions of the USSR and aimed at estimation of the contamination of products supplied by industrial poultry complexes (IPC), revealed that the contamination of these products was closely related to the Campylobacter contamination of the personnel of IPC. The causes of high Campylobacter contamination of the products of IPC at all technological stages of their production are described. The species, serovars and biovars of Campylobacter strains isolated from different sources were determined, which made it possible to carry out the specific and intraspecific differentiation of these strains.     

The spread of the causative agent of yersiniosis in the regions of Sochi and adjacent areas

Yersinia enterocolitica sensu stricto, Y. kristensenii, Y. aldovae and Y. intermedia strains were for the first time isolated in the Sochi districts from people, synanthropic rodents and washings from vegetables. In the adjacent alpine and subalpine areas isolates were obtained from wild rodents. 86.7% of the isolated strains were assigned to the known antigenic variants; O16; O5; O6.31; O7.8 and O6.30 serovars were predominant. All the strains isolated from people belonged to biovar 1 and O5; O6.31; O6.30 and O10 serovars. Y. intermedia and Y. aldovae belonged to O1, 2a, 3 and O16 serovars respectively. Y. kristensenii could not be agglutinated with sera against type strains of Yersiniae represented in the antigenic scheme of Wauters et al.     

Incidence of Listeria monocytogenes in Nature

During a research project on the occurrence of Listeria monocytogenes 194 strains were isolated in southern West Germany during the years 1972 to 1974: 154 from soil and plant samples (20.3%), 16 from feces of deer and stag (15.7%), 9 from old moldy fodder and wildlife feeding grounds (27.2%), and 8 from birds (17.3%). The highest number of isolates was obtained from uncultivated fields. The beta-hemolytic serovars 1/2b and 4b were predominant; other serovars (some of them identified for the first time), including nonhemolyzing strains, have been encountered frequently. It is suggested that Listeria monocytogenes is a saprophytic organism which lives in a plant-soil environment and therefore can be contracted by humans and animals via many possible routes from many sources.     

Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina

Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations.     

The prevalence of Yersinia and its serologic variants in patients with acute intestinal diseases of undetermined etiology in Leningrad

Among Yersinia enterocolitica strains of 32 serovars, proposed as typing strains, some strains were found to belong to new species. Y. enterocolitica sensu stricto was represented by 21 serovars in the collection of typing strains. The occurrence of different Yersinia serovars in patients with acute enteric diseases of unknown etiology in Leningrad in 1983-1986 was determined with the use of the set of monoreceptor to 21 serovars. Out of 2,947 cultures studied by biochemical and serological methods, 81% were typed. Among them 18 Y. enterocolitica serovars were determined. Their characteristic feature was the prevalence of serovar O3 and an insignificant proportion of serovar O9. More frequently Yersinia were detected in patients with the primary diagnosis of acute enteric diseases (93.5%). The overwhelming majority (two-thirds) of Yersinia strains were isolated from children. A great number of strains detected in this study (70%) was isolated on days 10-15 of the bacteriological examination. In 927 cultures the following biovars were determined: the strains of serovar O3 belonged to biovar 4 and all other strains, to biovar 1.     

Detection of virulence markers in clinical strains of Yersinia]

The dispersion of plasmid pYV associated virulence markers in 474 Yersinia strains isolated from people has been studied. The ability to autoagglutination, calcium dependence of growth and the specific antigens were identified in 157 strains of traditionally pathogenic Yersinia enterocolitica serovars 03, 09, Yersinia pseudotuberculosis serovar I. They were not found in 223 strains of other 12 serovars of Yersinia enterocolitica, in 40 strains of Yersinia frederiksenii, Yersinia kristensenii, Yersinia intermedia. The proportion of virulent clones in the population of Yersinia is noted to depend on the conditions of its existence in vivo or in vitro. Identification of virulence markers is acknowledged to be expedient in epidemiological and ethiological estimation of the role of isolated Yersinia strains.     

Characteristics of the serological passage of Escherichia isolated from children and adults with acute intestinal infections

The serological picture of Escherichia (5,910 strains), isolated from 1,430 inpatients (486 adults and 944 children) with acute intestinal infections by means of new diagnostic preparations (Escherichia rapid agglutinating O- and H-systems), was studied. In 15% of the adults and 26-28% of the children no Escherichia were detected. The serological picture of Escherichia proved to comprise 143 O-groups and 334 serovars; about 50% of the strains belonged to 11 prevailing O-groups: O1, O2, O4, O6, O7, O8, O9, O16, O21, O75, O85. The serological picture in the adults was more variegated than that in the children: from most of the patients (77.2%) Escherichia were isolated as a mixture of 2-9 serovars. The isolation rate of Escherichia monocultures and the incidence of Escherichia belonging to different O-groups were the same in patients of different ages, with the exception of groups O4, O6, O26, O55 and O111 which were more frequent in young children.     

Biogeochemical regioning problems and the biogeochemical selenium provinces in the former USSR

Current trends in biogeochemical research in the former USSR are exemplified for the trace element selenium (Se). Vast regions of the former USSR are low in Se, giving rise to selenium deficiency diseases in animals and to Kaschin-Beck disease in humans, whereas isolated high-Se regions are comparatively rare. The Se content of plants depends on geological soil-type and secondary processes such as weathering and leaching. In general, a direct correlation between the Se content of feedstock and of the blood in animals is observed, whereas corresponding data for humans remain to be accumulated.     

Vntr-genotyping of Francisella tularensis strains isolated in the former USSR territory and some European countries during epizootics in 1988 - 1989

Retrospective VNTR-analysis of 159 Francisella tularensis subsp. holarctica strains isolated in December 1988 - February 1989 in former USSR and some European countries was carried out. Analysis of heterogenic genotypes of strains allow to subdivide them into 30 groups of variants by individual genotypes, while cluster analysis--to subdivide them in 7 clusters with different number of compositions. The predominance of genotype C1 strains isolated on the Rostov and Archangelsk regions and the Crimea was established. F. tularensis strains isolated in winter time 1988 - 1989 in different geographic regions were supposed to be resident cultures typical for their biotope in natural focus of disease.