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.     

Features of Salmonella serovars among food handlers in Kyushu, Japan

Salmonella were isolated from 106 (0.032%) of 331,644 fecal samples from food handlers, and from 144 of 11,478 fecal samples from symptomatic patients in Japan to determine the incidence and features of Salmonella serovars among food handlers. S. enterica subspecies enterica serovar Infantis (S. serovar Infantis) was the dominant serovar (accounting for 48.1%), followed by S. serovar Corvallis, which showed poor genetic diversity, and S. serovar Enteritidis among food handlers. The former two serovars were not dominant among symptomatic patients. The present study demonstrates the need for education on the sanitary handling of chicken eggs and chicken meat, which are possible infectious sources of these Salmonella serovars.     

Genomic rearrangements at rrn operons in Salmonella

Most Salmonella serovars are general pathogens that infect a variety of hosts. These "generalist" serovars cause disease in many animals from reptiles to mammals. In contrast, a few serovars cause disease only in a specific host. Host-specific serovars can cause a systemic, often fatal disease in one species yet remain avirulent in other species. Host-specific Salmonella frequently have large genomic rearrangements due to recombination at the ribosomal RNA (rrn) operons while the generalists consistently have a conserved chromosomal arrangement. To determine whether this is the result of an intrinsic difference in recombination frequency or a consequence of lifestyle difference between generalist and host-specific Salmonella, we determined the frequency of rearrangements in vitro. Using lacZ genes as portable regions of homology for inversion analysis, we found that both generalist and host-specific serovars of Salmonella have similar tolerances to chromosomal rearrangements in vitro. Using PCR and genetic selection, we found that generalist and host-specific serovars also undergo rearrangements at rrn operons at similar frequencies in vitro. These observations indicate that the observed difference in genomic stability between generalist and host-specific serovars is a consequence of their distinct lifestyles, not intrinsic differences in recombination frequencies.     

Analysis of differential proteomes in pathogenic and non‐pathogenic Leptospira: Potential pathogenic and virulence factors

Leptospirosis is a bacterial zoonotic disease caused by spirochetes in the genus Leptospira. To date, factors determining the pathogenicity and virulence of leptospires remain unclear. We performed a gel‐based proteomic analysis to evaluate differential leptospiral proteomes in the pathogenic L. interrogans (serovars Australis, Bratislava, Autumnalis, and Icterohaemorrhagiae) and the non‐pathogenic L. biflexa (serovar Patoc). Quantitative proteome analysis and MS protein identification revealed 42 forms of 33 unique proteins whose levels were significantly greater in the pathogenic serovars compared with the non‐pathogenic serovar. Among the four pathogenic serovars, the more virulent serovar Icterohaemorrhagiae (which is most commonly associated with severe leptospirosis in patients) had significantly greater levels of 14 forms of 12 unique proteins, when compared with the other three pathogenic serovars. Some of these identified proteins may serve as the pathogenic and/or virulence factors of leptospirosis.     

Antibodies to Yersinia enterocolitica and Proteus mirabilis in blood sera of rheumatoid arthritis patients

Data on specific antibodies to the bacterial antigens of Yersinia enterocolitica (serovars 03, 09) and Proteus mirabilis in rheumatoid arthritis (RA) patients are presented. According to the data of some researchers, these organisms play some role in the pathogenesis of RA. The highest level of IgG antibodies to Y. enterocolitica antigens of both serovars was noted. The activity of specific IgG antibodies to serovar 03 was higher than that to serovar 09. In the sera of RA patients with P. mirabilis antgens the activity of IgM antibodies was higher.     

Pathogenic Leptospiras Isolated from Malaysian Surface Waters

Pathogenic leptospiras (1,424) isolated from natural waters and wet soils in Malaysia comprised 29 different serovars (synonym serotypes). All except two of the serovars had been found previously in Malaysia. The exceptional serovars were werrasingha, an Autumnalis serogroup member originally isolated in Ceylon, and a new serovar designated evansi. Serovar evansi had serological affinities with serovar ranarum which was isolated from the kidney of a frog in Iowa. The large variety of serovars found in jungle areas was consistent with similar previous findings of diverse serovar infections in troops who had operated in Malaysian jungles.     

Genomic comparison of Salmonella enterica serovars and Salmonella bongori by use of an S. enterica serovar typhimurium DNA microarray

The genus Salmonella consists of over 2,200 serovars that differ in their host range and ability to cause disease despite their close genetic relatedness. The genetic factors that influence each serovar's level of host adaptation, how they evolved or were acquired, their influence on the evolution of each serovar, and the phylogenic relationships between the serovars are of great interest as they provide insight into the mechanisms behind these differences in host range and disease progression. We have used an Salmonella enterica serovar Typhimurium spotted DNA microarray to perform genomic hybridizations of various serovars and strains of both S. enterica (subspecies I and IIIa) and Salmonella bongori to gain insight into the genetic organization of the serovars. Our results are generally consistent with previously published DNA association and multilocus enzyme electrophoresis data. Our findings also reveal novel information. We observe a more distant relationship of serovar Arizona (subspecies IIIa) from the subspecies I serovars than previously measured. We also observe variability in the Arizona SPI-2 pathogenicity island, indicating that it has evolved in a manner distinct from the other serovars. In addition, we identify shared genetic features of S. enterica serovars Typhi, Paratyphi A, and Sendai that parallel their unique ability to cause enteric fever in humans. Therefore, whereas the taxonomic organization of Salmonella into serogroups provides a good first approximation of genetic relatedness, we show that it does not account for genomic changes that contribute to a serovar's degree of host adaptation.     

Amplified fragment length polymorphism (AFLP) analysis of Listeria monocytogenes

AFLP analysis using four selective primers was performed on a set of 33 Listeria monocytogenes including strains from patients and foods implicated in outbreaks, human sporadic cases or foods. Strains were tested belonging to serovars 1/2a, 1/2b, 1/2c, 3b, and 4b. Using one of the primers, the AFLP technique generated 20 different sized DNA fragments. The 33 cultures segregated into 14 different patterns, each comprising 7-12 different fragments. Although the method was not sufficiently discriminatory for epidemiological typing, AFLP analysis reconfirmed the observation that L. monocytogenes comprises two major genetic groups: group 1 includes strains of serovars 1/2a and 1/2c, while group 2 serovars 1/2b, 3b and 4b.     

Genetic characterization of pathogenic Leptospira species by DNA hybridization.

A total of 66 serovars of potentially pathogenic Leptospira species were examined by slot blot hybridization, and 57 of these serovars were classified in six DNA homology groups. In cases in which common serovars were studied, the results were in general agreement with the results of previous workers, who used different DNA homology methods. However, we propose a new species, Leptospira kirschneri, comprising the following serovars: bulgarica, butembo, cynopteri, dania, grippotyphosa, kabura, kambale, ramisi, and tsaratsovo. Seven of these serovars have not had their DNAs studied by other workers.     

Comparison of genetic maps for two Leptospira interrogans serovars provides evidence for two chromosomes and intraspecies heterogeneity.

Genetic maps were constructed for Leptospira interrogans serovars icterohaemorrhagiae and pomona. Previously we independently constructed physical maps of the genomes for these two serovars. The genomes of both serovars consist of a large replicon (4.4 to 4.6 Mb) and a small replicon (350 kb). Genes were localized on the physical maps by using Southern blot analysis with specific probes. Among the probes used were genes encoding a variety of essential enzymes and genes usually found near bacterial chromosomal replication origins. Most of the essential genes are on the larger replicon of each serovar. However, the smaller replicons of both serovars contain the asd gene. The asd gene encodes aspartate beta-semialdehyde dehydrogenase, an enzyme essential in amino acid and cell wall biosyntheses. The finding that both L. interrogans replicons contain essential genes suggests that both replicons are chromosomes. Comparison of the genetic maps of the larger replicons of the two serovars showed evidence of large rearrangements. These data show that there is considerable intraspecies heterogeneity in L. interrogans.     

Comparative genome analysis of 19 Ureaplasma urealyticum and Ureaplasma parvum strains

ABSTRACT: BACKGROUND: Ureaplasma urealyticum (UUR) and Ureaplasma parvum (UPA) are sexually transmitted bacteria among humans implicated in a variety of disease states including but not limited to: nongonococcal urethritis, infertility, adverse pregnancy outcomes, chorioamnionitis, and bronchopulmonary dysplasia in neonates. There are 10 distinct serotypes of UUR and 4 of UPA. Efforts to determine whether difference in pathogenic potential exists at the ureaplasma serovar level have been hampered by limitations of antibody-based typing methods, multiple cross-reactions and poor discriminating capacity in clinical samples containing two or more serovars. RESULTS: We determined the genome sequences of the American Type Culture Collection (ATCC) type strains of all UUR and UPA serovars as well as four clinical isolates of UUR for which we were not able to determine serovar designation. UPA serovars had 0.750.78 Mbp genomes and UUR serovars were 0.840.95 Mbp. The original classification of ureaplasma isolates into distinct serovars was largely based on differences in the major ureaplasma surface antigen called the multiple banded antigen (MBA) and reactions of human and animal sera to the organisms. Whole genome analysis of the 14 serovars and the 4 clinical isolates showed the mba gene was part of a large superfamily, which is a phase variable gene system, and that some serovars have identical sets of mba genes. Most of the differences among serovars are hypothetical genes, and in general the two species and 14 serovars are extremely similar at the genome level. CONCLUSIONS: Comparative genome analysis suggests UUR is more capable of acquiring genes horizontally, which may contribute to its greater virulence for some conditions. The 4 overwhelming evidence of extensive horizontal gene transfer among these organisms from our previous studies combined with our comparative analysis indicates that 6 ureaplasmas exist as quasispecies rather than as stable serovars in their native environment. Therefore, differential pathogenicity and clinical outcome of a ureaplasmal infection is most likely not on the serovar level, but rather may be due to the presence or absence of potential pathogenicity factors in an individual ureaplasma clinical isolate and/or patient to patient differences in terms of autoimmunity and microbiome.     

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.     

Rapid identification of Salmonella enterica serovars, Typhimurium, Choleraesuis, Infantis, Hadar, Enteritidis, Dublin and Gallinarum, by multiplex PCR

Salmonella enterica subsp. enterica poses a threat to both human and animal health, with more than 2500 serovars having been reported to date. Salmonella serovars are identified by slide and tube agglutination tests using O and H antigen-specific anti-sera, although this procedure is both labor intensive and time consuming. Establishment of a method for rapid screening of the major Salmonella serovars is therefore required. We have established multiplex polymerase chain reaction (m-PCR) assays for identification of seven serovars of Salmonella, i.e., Typhimurium, Choleraesuis, Infantis, Hadar, Enteritidis, Dublin and Gallinarum. Three serovar-specific genomic regions (SSGRs) of each serovar were selected using an approach in comparative genomics. The Salmonella-specific invA gene was used to confirm the genetic background of the organisms. The isolates tested were identified as a target serovar when the three selected SSGRs and invA were all positive for amplification. The specificity of each m-PCR assay was investigated using 118 serovars of Salmonella and 12 species of non-Salmonella strains. Although a small number of false-positive results were observed in the m-PCR assays used to identify Typhimurium, Choleraesuis, Enteritidis and Dublin for closely related serovars, false-negative results were not observed in any assays. These assays had sufficient specificity to identify the seven Salmonella serovars, and therefore, have the potential for use as rapid screening methods.     

Emergence and serovar transition of Vibrio parahaemolyticus pandemic strains isolated during a diarrhea outbreak in Vietnam between 1997 and 1999

We characterized 523 Vibrio parahaemolyticus strains isolated during a survey of diarrhea patients in Khanh Hoa province, Vietnam between 1997 and 1999. Forty-nine percent of the strains were judged to belong to the pandemic strains that emerged around 1996 and spread to many countries. These strains were positive in the GS-PCR assay and carried the tdh gene. The ORF8 of the f237 phage genome, a possible marker of the pandemic clone, was absent in 10% of these strains. Eleven O: K serovars were detected among the pandemic strains and the strains representing all 11 serovars of pandemic strains were shown to be closely related regardless of the ORF8 genotype using arbitrarily primed PCR and pulsed field gel electrophoresis analyses. It was clear that a transition of major serovars occurred among the pandemic strains represented by the emergence of O3: K6 in 1997, O4: K68 in 1998, and O1: K25 in 1998 and 1999.     

On the serology of Plesiomonas shigelloides

The serology of 87 strains of Plesiomonas shigelloides was studied. Thirty O antigenic groups and 11 H antigens were defined within the 87 strains, and an antigenic schema consisting of 40 serovars was established. Some O antigens of P. shigelloides were identical or closely related to those of some Shigella serovars.     

Immunochemical study of the lipopolysaccharides of Yersinia enterocolitica serovars O5 and O5.27

Y. enterocolitica lipopolysaccharides (LPS), serovars O5 and O5.27, have similar antigenic specificity. The LPS of serovar O5.27 has been shown to contain no factor O27. Residual alpha-L-rhamnose, glycosylated by D-xylulose, has been found to play an important role in the formation of factor O5, common for both serovars.     

Diversity of Chlamydia trachomatis major outer membrane protein genes.

Genomic DNA libraries were constructed for Chlamydia trachomatis serovars B and C by using BamHI fragments, and recombinants that contained the major outer membrane protein (omp1) gene for each serovar were identified and sequenced. Comparisons between these gene sequences and the gene from serovar L2 demonstrated fewer base pair differences between serovars L2 and B than between L2 and C; this finding is consistent with the serologic and antigenic relationships among these serovars. The translated amino acid sequence for the major outer membrane proteins (MOMPs) contained the same number of amino acids for serovars L2 and B, whereas the serovar C MOMP contained three additional amino acids. The antigenic diversity of the chlamydial MOMP was reflected in four sequence-variable domains, and two of these domains were candidates for the putative type-specific antigenic determinant. The molecular basis of omp1 gene diversity among C. trachomatis serovars was observed to be clustered nucleotide substitutions for closely related serovars and insertions or deletions for distantly related serovars.     

胸膜肺炎放线杆菌基因分型方法的建立及其临床应用

根据胸膜肺炎放线杆菌各血清型之间外毒素(Apx),外膜脂蛋白(OmlA),转铁蛋白B(TbpB)的基因差异,分别对各血清型进行PCR扩增,得到不同的特异性片段,可区分开生物Ⅰ型13个标准菌株血清型中的8个血清型。临床检测结果与血清学分型一致,将此分型系统用于临床送检的126份肺脏和42份扁桃体的病原学检测,可直接检测出胸膜肺炎放线杆菌感染。此方法还可以将一些尚未定型的菌株进行归类,弥补了血清学方法的不足,为细菌的流行病学调查提供了可靠的技术手段。     

Identification of Salmonella enterica subspecies I, Salmonella enterica serovars Typhimurium, Enteritidis and Typhi using multiplex PCR

This study was designed to develop a multiplex PCR method with five specific primer pairs for the detection of Salmonella spp., Salmonella subspecies I, Salmonella enterica serovars Typhimurium, Typhi and Enteritidis. A multiplex PCR was constructed with five primer pairs for the detection of Salmonella and pathogenic Salmonella serovars, including a specific primer pair for Salmonella Typhi, based on the sequence comparison between genomic DNA sequences of 12 Salmonella strains. Each primer pair was specifically targeted to Salmonella spp., Salmonella subspecies I, Salmonella Typhimurium, Typhi and Enteritidis. This multiplex PCR was evaluated with various DNAs of Salmonella serovars that yielded high specificity for amplifying the expected PCR products of Salmonella serovars. Using this primer pair, a set of multiplex PCR was performed for the rapid identification of salmonellae and major pathogenic Salmonella serovars. Although this multiplex PCR method will need to be evaluated for a wide range of Salmonella serovars among multilaboratories, it should be useful for identifying clinically significant strains of Salmonella serovars rapidly and accurately without the need for serological testing.     

Identification and characterization of novel salmonella mobile elements involved in the dissemination of genes linked to virulence and transmission

The genetic diversity represented by >2,500 different Salmonella serovars provides a yet largely uncharacterized reservoir of mobile elements that can contribute to the frequent emergence of new pathogenic strains of this important zoonotic pathogen. Currently, our understanding of Salmonella mobile elements is skewed by the fact that most studies have focused on highly virulent or common serovars. To gain a more global picture of mobile elements in Salmonella, we used prediction algorithms to screen for mobile elements in 16 sequenced Salmonella genomes representing serovars for which no prior genome scale mobile element data were available. From these results, selected mobile elements underwent further analyses in the form of validation studies, comparative analyses, and PCR-based population screens. Through this analysis we identified a novel plasmid that has two cointegrated replicons (IncI1-IncFIB); this plasmid type was found in four genomes representing different Salmonella serovars and contained a virulence gene array that had not been previously identified. A Salmonella Montevideo isolate contained an IncHI and an IncN2 plasmid, which both encoded antimicrobial resistance genes. We also identified two novel genomic islands (SGI2 and SGI3), and 42 prophages with mosaic architecture, seven of them harboring known virulence genes. Finally, we identified a novel integrative conjugative element (ICE) encoding a type IVb pilus operon in three non-typhoidal Salmonella serovars. Our analyses not only identified a considerable number of mobile elements that have not been previously reported in Salmonella, but also found evidence that these elements facilitate transfer of genes that were previously thought to be limited in their distribution among Salmonella serovars. The abundance of mobile elements encoding pathogenic properties may facilitate the emergence of strains with novel combinations of pathogenic traits.