Biomedical subjects
Publications and source records attributed to R Sakazaki.
Two serogroups of Vibrio cholerae non-O1 possessing somatic antigen factors in common with Hakata serogroup of V. cholerae are described. One group was included in the Hakata serogroup and has its own antigen other than all O-antigens of the Hakata group. The other group had its own major antigen, but not factor F specific for the Hakata group.
A new selective and differential agar medium, polymyxin-mannose-tellurite (PMT) agar was devised to differentiate easily colonies of Vibrio cholerae O1 from those of V. cholerae non-O1. The differentiation between colonies of the two vibrios is based on mannose-fermentation. Colonies of V. cholerae O1 on the agar are agglutinated with O1 antiserum of V. cholerae much more easily than those on thiosulfate-citrate-bile salts-sucrose (TCBS) agar.
In a year-long, case-control study of endemic diarrheal disease among 1230 Thai children less than five years of age, rotavirus was detected in 20%, Campylobacter in 13%, Shigella in 13%, Salmonella in 12%, and enterotoxigenic Escherichia coli (ETEC) in 9%. The differences in detection of enteric pathogens between patients and controls was significant for rotavirus (P less than .001), Shigella (P less than .001), ETEC that produced heat-labile and heat-stable toxins (LT and ST; P = .005), and ST only (P less than .001). C. jejuni was most significantly associated with diarrhea in children less than 12 months [corrected] old (P = .037) and Salmonella in children less than three months of age (P = .003). Enteropathogenic E. coli (EPEC) that adhered in a localized pattern to HeLa cells was isolated from 7% of patients and 3% of controls less than six months of age. Only 50% of these E. coli strains were of EPEC serotypes. Enteroinvasive E. coli was isolated from 7% of patients more than two years of age, and new serotypes were identified.
New antibiotics, agglomerins A, B, C and D, were isolated from the culture broth of a bacterial strain identified as Enterobacter agglomerans. These antibiotics are acidic in nature and their sodium salts are obtained as colorless crystalline powders, soluble in lower alcohols. All the antibiotics shows characteristic UV maxima at 248 and 298 nm. Molecular formulas: A, C15H21O4Na; B, C17H23O4Na; C, C17H25O4Na and D, C19H27O4Na; were indicated by elemental analysis and MS. These antibiotics are active against a wide variety of anaerobic bacteria and weakly against aerobic Gram-positive bacteria in vitro.
A new antifungal antibiotic, CB-25-I, was isolated from the culture broth of a strain of Serratia plymuthica. The antibiotic, a water-soluble dipeptide, is structurally related to Sch 37137 and A 19009, both produced by strains of Actinomycetales. The antibiotic exhibits inhibitory activity against Candida albicans in YNB medium (a synthetic medium), but the activity is significantly reduced in Sabouroud dextrose medium.
Eighteen strains of Salmonella choleraesuis subsp. choleraesuis serovar Typhi (S. typhi) isolated from blood of patients in Japan who had visited Indonesia and returned before the onset of typhoid fever were found to possess the H-antigen Z66 reported by Guinée et al. (1981) but had the naturally occurring H-antigen d. They were not lysed by any of the phages of the Vi phage typing system. After passage through semi-solid medium containing H-Z66 antiserum, H-antigens of 11 of 18 cultures with H-Z66 phage changed to H-j and those of 2 others to H-d, while the remaining 5 were immobilized. With cultures in the H-d or H-j phages, change of the H-antigens did not occur when they were cultured in semi-solid medium containing homologous H-antiserum. These phase induction experiments as well as colony examination of original cultures suggest that H-Z66 phase is unstable and tends to change to the H-j phase. It also suggest that the original H-Z66 cultures in which change of H-antigen to H-d or H-j occurred without difficulty probably represented a mixed population of cells in the H-Z66 and H-d or H-j phases. Since none of 856 isolates from Japan or from imported cases of typhoid fever from Southeast Asia other than Indonesia exhibited the H-Z66 antigen, it was concluded that the focus of typhoid fever caused by S. typhi in H-Z66 phase was probably in Indonesia.
A serogroup of non-O1 Vibrio cholerae, tentatively named Hakata, possessing the C (Inaba) factor but not the B (Ogawa) and A factors of V. cholerae O1 is described. Strains of this serogroup were isolated from river and estuarine waters and from frozen shrimps.
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The surface characteristics of 24 autoagglutinating (AA+) mesophilic aeromonads were investigated. One group of 16 was found to be highly related serologically by their reactive pattern against O antisera generated against three reference strains. Subsequent characterization of 11 of these isolates (group 1) indicated that they had the following properties in common: precipitation after boiling (PAB+), membership of serogroup O:11 (typing scheme of Sakazaki and Shimada), resistance to lysis by bacteriophage Aeh1, and possession of a surface layer (S layer) as determined by transmission electron microscopy. Strains not exhibiting the same serologic reactivity pattern belonged to diverse serogroups (other than O:11), were generally susceptible to lysis by Aeh1, and were S layer negative by transmission electron microscopy (group 2). Analysis of selected isolates representing both groups indicated that group 2 strains were usually more hydrophobic than group 1 isolates in several different assays; both groups, however, possessed high surface charge as determined by binding to DEAE-cellulose. Group 1 isolates were more virulent than group 2 strains tested as determined by lower 50% lethal doses for mice. On the basis of the results of the kinetics of autoagglutination in broth, relative surface hydrophobicity, uptake of Congo red, agglutination of yeast cells, and electrophoretic protein profiles of whole-cell extracts, the surface layer associated with O:11 mesophilic aeromonads appears to be distinct from that of Aeromonas salmonicida. The results suggest that a new pathogenic group of mesophilic aeromonads linked through a common AA phenotype, serogroup, and S layer cause serious infections in both humans and animals (fish).
A combination of two systems for the serotyping of Edwardsiella tarda developed independently at the National Institute of Health, Tokyo, Japan, and the Centers for Disease Control, Atlanta, Ga., has enabled a single serotyping scheme comprising 61 O groups and 45 H antigens to be established for international use.
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A new phenazine antibiotic, DOB-41, was isolated from the culture broth of a Pseudomonas strain. The antibiotic obtained as yellow crystals showed UV maxima at 255 nm and 370 nm. A molecular formula, C19H18N2O6, was indicated by elemental analysis and mass spectrometry. The structure was elucidated by X-ray diffraction analysis. The antibiotic exhibited inhibitory activity against Gram-positive bacteria, and antitumor effect against leukemia P388 in mice.
In recent years, a number of sporadic or community infections of Yersinia pseudotuberculosis were observed in several mountain area of Okayama Prefecture, Japan. Epidemiological observations strongly suggested that drinking water in those areas, i.e. non-chlorinated water from mountain stream or wells, must be the source of the infection, so we examined the waters from the epidemic areas to detect the organisms. The examinations revealed the germs in the waters; the contamination rate of water from the northern areas is higher than that from the southern urban regions. The isolation procedures for the germs were also studied and improved. The media added with blood or hemin proved to be better for isolation of the organism.
A bioserogroup of halophilic vibrios, tentatively labelled bioserogroup 1875, strongly agglutinated by O1 antiserum of Vibrio cholerae is described. Cross-agglutination and agglutinin-absorption tests showed that these vibrios had antigens identical with the Ogawa and Inaba factors of V. cholerae O1, although they possessed their own specific antigen distinctive from the A factor that is the specific major antigen of the latter species. In addition, quantitative antigen variation similar to that of the Ogawa-to-Inaba type with V. cholerae O1 was recognized in this halophilic group. They were isolated from estuarine water and are considered to inhabit coastal aquatic environments. Phenotypically, however, this group is not identifiable with any of the species already recognized in the genus Vibrio.
A serogroup of Vibrio fluvialis possessing the C (Inaba) antigen but not the B (Ogawa) nor A antigen of V. cholerae O1 is described. The O-antigen of this serogroup was identical with that of bioserogroup 1875-variant of a marine Vibrio species. As the O-antigen of this serogroup was not agglutinated by any of O-antisera for the 18 serogroups of V. fluvialis already recognized, it was designated O-serogroup 19 of this species.
The aerobic bacterial flora of the intestine of 150 wall geckos (Hemidactylus brookei) was investigated. A variety of bacteria was recovered including 35 isolates of Salmonella and several other species of Enterobacteriaceae, viz. Shigella sonnei - 2, Edwardsiella tarda - 4, Enterobacter spp - 8, Citrobacter freudii - 3, Serratia marcescens - 3, Proteus spp - 35, Klebsiella pneumoniae - 13, and Escherichia coli - 17, isolates. Eight Salmonella serotypes were identified, the predominant ones being S. hvittingfoss and S. typhimurium. The significance of these findings for the spread of human enteropathogens is discussed.