Identification of Plesiomonas spp.: serological and MALDI-TOF MS methods.

Biochemical and serological profiles of isolates of Plesiomonas shigelloides were assayed using standard procedures in isolates from various clinical samples. Seventy-four isolates, including P. shigelloides type strain, were further characterized by MALDI-TOF MS using 3-methoxy-4-hydroxycinnamic acid as matrix. Multiple ions in the 3- to 12-kDa mass range were found in the spectra of each strain, from which the "species-identifying" unique biomarker ions were identified. After creating the species-specific patterns, a spectral database was generated for reliable, rapid, reproducible and accurate identification of Plesiomonas strains. The classical strain description (biochemical and serological) was thus complemented with the metabolic (proteomic) characterization.

Enteropathogenicity of Plesiomonas shigelloides and Aeromonas spp. in experimental mono- and coinfection with Cryptosporidium parvum in the intestine of neonatal BALB/c mice.

Enteropathogenicity of Plesiomonas shigelloides, Aeromonas hydrophila, A. caviae and A. sobria was studied both in monoinfections and in coinfections with coccidium Cryptosporidium parvum in neonatal BALB/c mice. In monoinfection experiments, neonatal BALB/c mice were orally infected with 7 x 10(7) or 7 x 10(8) CFU, respectively, of a strain of P. shigelloides or a strain of an Aeromonas spp. In coinfection experiments, the neonatal mice were, in addition to being orally infected with one of the four bacterial species, orally infected with an inoculum containing 10(5) oocysts of C. parvum. Results from monoinfections with P. shigelloides revealed long-term colonisation of the neonatal mouse intestine by this pathogen, along with associated pathological lesions. The lesions varied in severity from atrophy to necrosis of the mucosal inner surface of the ileum and colon, with predilection to the colon and brush border of colonic enterocytes. The effects of coinfection of P. shigelloides with C. parvum were characterised by bacteremia and heavy colonisation of the intestine by P. shigelloides. In addition, extensive necrotising inflammatory changes in the ileum and colon were accompanied by diarrhoea and deaths of coinfected mice. In contrast, the results from monoinfections of neonatal mice with Aeromonas spp. showed only a short-term colonisation of the intestine by the pathogen. However, when mice were coinfected with A. hydrophila and C. parvum, then the growth of the bacterial species was prolonged, and occurred in both the spleen and intestine. However, no substantial clinical or histopathological changes were observed in mice, whether monoinfected with Aeromonas spp. or coinfected with C. parvum. Our study suggests that experimental monoinfections of neonatal BALB/c mice with P. shigellodes, Aeromonas spp. and C. parvum, together with coinfections (each bacterial species with the protozoan C. parvum), may serve as a useful model to study the initial steps of gastrointestinal colonisation and diarrhoeal disease syndromes caused by enteropathogenic bacteria and protozoa, individually and in combination.

New serovars of Plesiomonas shigelloides--1992-1998.

Most of the 26 new O (O77-O102) and 10 new H (H42-H50) and H1a1d antigens were found in various P. shigelloides strains isolated from man and other mammals, birds, fish, and water and water insects, not only in the Czech Republic but also in 12 foreign countries.

Structural studies of the O-specific polysaccharide from Plesiomonas shigelloides strain CNCTC 113/92.

The structure of the O-specific side chain of the lipopolysaccharide (LPS) of Plesiomonas shigelloides, strain CNCTC 113/92 has been investigated by NMR spectroscopy, matrix-assisted laser desorption/ionization time of flight mass spectrometry and sugar and methylation analysis. It was concluded that the polysaccharide is composed of a hexasaccharide repeating unit with the following structure: in which D-beta-D-Hepp is Dglycero-beta-Dmanno-heptopyranose and 6d-beta-D-Hep is 6-deoxy-beta-Dmanno-heptopyranose. This structure represents a novel hexasaccharide repeating unit of bacterial O-antigen that is characteristic and unique to the Plesiomonas shigelloides strain. Using the high-resolution magic angle spinning technique, 1H-NMR spectra were also obtained for the O-polysaccharide components of isolated LPS and in their original form directly on the surface of bacterial cells.

New O and H antigens of the international antigenic scheme for Plesiomonas shigelloides.

A revised update of the International antigenic scheme for Plesiomonas shigelloides is presented. Twenty-six new O (O77-O102) and 10 new H (H42-H50 and H1a1d) antigens have been described since 1994. The sources of antigens are mostly human clinical strains, isolates from warmblooded animals and a few environmental cultures.

Biochemical identification of Citrobacter species defined by DNA hybridization and description of Citrobacter gillenii sp. nov. (formerly Citrobacter genomospecies 10) and Citrobacter murliniae sp. nov. (formerly Citrobacter genomospecies 11).

Recent work describing six named species and two unnamed genomospecies within Citrobacter has enlarged the genus to 11 species. DNA relatedness and phenotypic tests were used to determine how well these species can be identified. One hundred thirty-six strains were identified to species level by DNA relatedness and then identified phenotypically in a blinded fashion. By using conventional tests, 119 of the 136 strains (88%) were correctly identified to species level. Three additional strains (2%) were identified as citrobacteria but were not identified to species level, and 14 strains (10%) were misidentified as other Citrobacter species. Carbon source utilization tests were used to identify 86 of the strains. Eighty-four strains (98%) were correctly identified, and two strains (2%) were misidentified as other Citrobacter species. Additional strains of Citrobacter genomospecies 10 and Citrobacter genomospecies 11 were identified, allowing these species to be formally named as Citrobacter gillenii sp. nov. and Citrobacter murliniae sp. nov., respectively.

Plesiomonas shigelloides in water and fish.

Plesiomonas shigelloides strains isolated from aquariums, surface water and fish were serotyped using the international antigenic scheme and a provisional scheme designed for environmental strains, called the "Schubert" scheme. A remarkable variety of serovars represented in both schemes was found, namely in surface water samples and in fish.

Characterization of Plesiomonas shigelloides from diarrheic children.

Infrastructure of 29 P. shigelloides strains isolated as the only positive finding from children with diarrhea (biochemical properties, antigenic structure, antigenic relationship to shigellae, ATB susceptibility and plasmids) were described. A big variety of 22 serovars in a relatively small number of strains was found, inclusive four new 0 (093, 094, 095 and 096) and one new H (H46) antigen. Some strains belonged to the so-called "Schubert antigenic scheme" the serovars of which come of surface water of small ponds in Germany.

New serovars of plesiomonas shigelloides--1996.

Eight new 0 (91-98) and H (46-49) antigens are described. Their reference strains come from Czech Republic, Cuba and USA. The majority of reference strains are of human origin. Some of the new antigens have been found in other strains coming mostly from water.

Detection and identification of Citrobacter sedlakii in the Czech Republic.

The biochemical characters of eight strains identified as Citrobacter sedlakii were investigated with the aid of six methods (tube tests, API 50 CH, API 20 E, MICROSCAN, BIOLOG, and CRYSTAL). All the strains were well defined on the basis of biochemical properties investigated with the aid of laboratory-prepared tube tests. The results obtained by the identification kits could not be correctly interpreted. Commercial diagnostic kits should include the reference data necessary for the identification of new Citrobacter species.

[The importance of serotyping Plesiomonas shigelloides]. / Význam sérotypizace Plesiomonas shigelloides.

The author presents an account of serovars of 432 strains of Plesiomonas shigelloides from various countries and sources; in addition to strains from man and animals also environmental strains. The most frequent serovars are O17 with three H antigens (H2, H11, H34) except for immobile strains, also O32:H4 and non-motile strains, O2:H1a1c and O44:H8. The other serovars did not reach the number of 10 strains, some serovars were found only one strain of each. Serovar O18:H2 was isolated in the course of 30 years only from cats and lynx and once from a pond in the FRG. As regards the distribution of different serovars, e.g. O68:H2 was found only in one district, while strains of the serogroup O17 come from various countries in the world. Between findings of the same serovar sometimes a 20-30-year interval elapses.

[Biochemical indicators of Citrobacter sedlakii]. / Biochemické znaky Citrobacter sedlakii.

The authors describe eight strains identified biochemically as a new species of C. sedlakii in clinical material, surface water and the cutting surface of a melon. The majority of strains was isolated in the Czech and Slovak Republic.

New serovars of Plesiomonas shigelloides 1992.

Fourteen new O (O77-O9O) and 4 new H (H42-H45) antigens were described. Seven O and 2 new H antigens were revealed among strains not agglutinating with antisera against 76 O and 41 H officially recognized serovars. The most frequent was serovar O80:H38 which was isolated in 5 countries (Sweden, Czechoslovakia, Bulgaria, Yugoslavia and Canada) from human material and from sewage and surface water.

Serovars of Plesiomonas shigelloides.

Among 391 P. shigelloides strains, 330 were typable and found to belong to 43 O serovars. The most frequent O serovars were O17 (23%), O32 (7%), O12 (4.5%) and O5, O18 and O44 (3.8% each). The majority of the serovars represented, with almost 300 strains, were sporadically found in very distant countries of three continents (Europe, Asia, America), whereas only one serovar (O68) was isolated three times in one single district of South Bohemia (Ceské Budéjovice). It suggests that such an incidence of plesiomonads is only seemingly sporadic and that there must be many strains which are not detected owing to the imperfect cultivation methods used so far.

[Biochemical identification of aeromonads]. / Biochemická identifikace aeromonád.

To assess the species of the genus Aeromonas in 178 strains isolated from human and animal materials and from the environment (water and hospital environment), examined along with 11 type strains of the best known species, a key was used the basis of which are in addition to biochemical tests defining the genus Aeromonas 12 tests: Voges-Proskauer, lysine decarboxylase, gas from glucose, haemolysis, gluconate oxidation, elastase, arabinose, mannose, saccharose, salicine, esculine hydrolysis, arbutine. Three tests--salicine, esculine hydrolysis, arbutine--differentiate A. hydrophila (2-3 positive) from A. sobria (0-1 positive).

[Isolation of a rare serovar of Plesiomonas shigelloides]. / Izolácia vzácneho sérovaru Plesiomonas shigelloides.

The authors describe the isolation of a rare serovar Plesiomonas shigelloides from a patient with diarrhoea. The isolated strain belongs according to a combined Japanese-Czechoslovak antigenic scheme to serovar 024 H"o". The interesting finding draws attention to the possibility of routine departments to contribute to investigations of the incidence, importance and antigenic structure of this bacterial species.

Pilot studies on the occurrence of some infectious diseases in two different areas in south Yemen (Aden) (part II. Microbiology).

This paper is the second part of the article dealing with intestinal bacteria. The findings are relatively poor in comparing with the frequency of intestinal protozoa. Among 83 stool specimens taken for bacteriological examination 14 isolations of different bacteria were proved. One S. muenchen was isolated from a 3 year old boy with fever, diarrhoea. Five cases of Alkalescens dispar 05 manit negative and 05 manit positive were identified. Two of these cases were without clinical symptoms. All were males aged 10-17 years. One isolation of E. coli EPEC 086 K6 H11 was in a 10 year-old boy with diarrhoea, four watery stools daily and cramps. Six cases of other E. coli were of different types, all with clinical symptoms. Of them three were males and three females at the age from 3-46 years. One case had a mixed infection of Citrobacter, E. coli and Klebsiella with diarrhoea, about 5 watery stools daily and abdominal pain. The frequency of intestinal bacteria in males was nearly three times higher than in females. The occurrence in age groups 10-20 was almost equal 20.0-22.2%, in 0-4 it was 42.9% and surprisingly low in 5-9 years old--3.4% only.

Classification of strains of Pragia fontium, Budvicia aquatica and of Leminorella by whole-cell protein pattern.

SDS PAGE protein patterns of 37 H2S-positive strains of species belonging to the family Enterobacteriaceae including the genera Budvicia (11 strains) and Leminorella (L. grimontii--3 strains, L. richardii--4 strains) were compared with 10 strains of species Pragia fontium. All strains under study form well separated clusters with overall similarity C = .49. Clusters are separated in the range of C = .68-.83. They display high homogeneity, only one strain of Edwardsiella tarda clusters with budviciae. Strains of Pragia form two distinct clusters separated from other genera. Electrophoretograms of two strains which do not group as expected are analyzed and results discussed. Results support evidence that strains designated Pragia fontium deserve independent treatment as a new species.