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A molecular-capsular-type prediction system for 90 Streptococcus pneumoniae serotypes using partial cpsA-cpsB sequencing and wzy- or wzx-specific PCR.

In a previous study, a molecular capsular type (MCT) prediction system for 51 Streptococcus pneumoniae serotypes was developed based on a combination of partial cpsA-cpsB sequencing and serotype(s)/group(s)-specific PCR. In this study, another 169 S. pneumoniae isolates were added to the existing database of 427 isolates, including representatives of all 39 serotypes not previously studied. In addition to the authors' own limited sequence data for all 90 serotypes, cpsA-cpsB sequence data published by the S. pneumoniae capsular loci-sequencing group (http://www.sanger.ac.uk/Projects/S_pneumoniae/CPS/) at the Sanger Institute or available from GenBank were incorporated into the database. All serotypes, except 25A, were represented by at least two isolates. The number of sequence types identified was 138, of which 110 corresponded to single conventional serotypes (CSs); of these, 57 were represented by two or more isolates. Twenty-six sequence types were shared by between two and four CSs. To resolve these shared cpsA-cpsB sequence types and increase the discriminatory power of our system, the genes encoding the capsular polysaccharide flippase (wzx) and polymerase (wzy) were annotated and 24 new serotype(s)/group(s)-specific PCRs targeting wzy and two targeting wzx were designed. Using both cpsA-cpsB sequencing and wzx/wzy PCR, MCT correctly predicted the CSs of 516 (73 %) and the serogroup of an additional 155 (22 %) of the 708 isolates evaluated. For 5 % of isolates, MCT could not distinguish between members of five serotype pairs (37 isolates) containing members of different serogroups. Although further study of the relationship between MCT and CS is needed, this system now allows serotype or serogroup identification of 95 % of S. pneumoniae isolates.

Bacterial Capsules↗

Identification and characterization of Shigella boydii 20 serovar nov., a new and emerging Shigella serotype.

Analysis of 163 putative Shigella isolates from Canada and the USA showed biochemical reactions consistent with Shigella species, although none of the isolates reacted with antiserum raised against any of the well-established or provisional Shigella serotypes. All these isolates, provisionally designated serotype SH108, were positive for the ipaH gene and the invasion-associated locus. All fermented mannitol, were serologically indistinguishable from each other and showed no reaction in antisera prepared against Escherichia coli serotypes O1 to O181. PCR-RFLP analysis of the genes involved in O-antigen synthesis revealed a common pattern among these isolates that was distinct from recognized Shigella serotypes and E. coli. Between 1999 and 2003, isolates from across Canada were submitted to the National Laboratory for Enteric Pathogens for antibiotic susceptibility testing, phage typing and PFGE. These assays revealed heterogeneity among the members of this serotype. Antimicrobial susceptibility testing with seven antibiotics identified six profiles, with 90 % (45/50) of the isolates resistant to four or more antibiotics and 72 % (36/50) resistant to five or more. All isolates were typable using a panel of 16 phages, with 11 different phage types (PTs) represented. The most common PTs found were PT 3 (64 %), PT 6 (10 %) and PT 16 (6 %). Analysis of XbaI-restricted genomic DNA revealed 16 highly related patterns that were not readily distinguishable from those obtained for some other Shigella serotypes. The World Health Organization Collaborating Center for Shigella has added serotype SH108 to the Shigella scheme as S. boydii serotype 20 (serovar nov.). Strain SH108 (isolate 99-4528) is the reference strain for this serotype.

Bacterial Typing Techniques↗

Isolation and characterization of the serotype g carbohydrate moiety from an enzyme lysate of Streptococcus mutans 6715 cell walls.

The serotype-specific carbohydrate moiety of Streptococcus mutans was isolated by mild degradation of purified cell walls with a cell-wall lytic enzyme. Cell walls of serotype g S. mutans strain 6715 were digested with M1 enzyme, an endo-N-acetylmuramidase purified from culture supernatants of Streptomyces globisporus strain 1829. The enzyme lysate of the cell walls was applied to a CM Sephadex C-25 column to remove the M1 enzyme from the cell wall lysate and then subjected to Sephadex G-100 column chromatography. Carbohydrate antigens with serotype g specificity, designated M1g, and a peptidoglycan--polysaccharide complex lacking serotype specificity (M1PG) were separated. Purified serotype g antigen was also obtained by autoclaving the S. mutans 6715 whole cells in saline at 120 C for 30 min. The extract was applied to a DEAE Sephadex A-25 column to remove nucleic acids and teichoic acids. The unbound peak fraction was concentrated and re-chromatographed on a Bio-Gel P-100 column. The void volume fraction contained serotype g carbohydrate and was designated RRg antigen. M1g and RRg antigens formed a band of identity with anti-serotype g serum by immunodiffusion. These antigens were composed mainly of galactose, glucose, and rhamnose at an approximate weight ratio of 8 : 4: 1, while constituent sugars of M1PG consisted of rhamnose and glucose, with no detectable galactose. M1g also contained peptidoglycan residues other than threonine, an interpeptide bridge component of the native cell wall peptidoglycan. Marked inhibition of the quantitative precipitin reaction between M1g and anti-serotype g serum was obtained with melibiose and galactose, which suggests that the immunodeterminant of the serotype g carbohydrate is an alpha-linked galactose-glucose terminal linkage.

Amino Acids↗

The diversity of Escherichia coli serotypes and biotypes in cattle faeces.

AIM: To study the diversity of commensal Escherichia coli populations shed in faeces of cattle fed on different diets. METHODS AND RESULTS: Thirty Brahman-cross steers were initially fed a high grain (80%) diet and then randomly allocated into three dietary treatment groups, fed 80% grain, roughage, or roughage + 50% molasses. Up to eight different E. coli isolates were selected from primary isolation plates of faecal samples from each animal. Fifty-two distinct serotypes, including nine different VTEC strains, were identified from a total of 474 E. coli isolates. Cattle fed a roughage + molasses diet had greater serotype diversity (30 serotypes identified) than cattle fed roughage or grain (21 and 17 serotypes identified respectively). Cluster analysis showed that serotypes isolated from cattle fed roughage and roughage + molasses diets were more closely associated than serotypes isolated from cattle fed grain. Resistance to one or more of 11 antimicrobial agents was detected among isolates from 20 different serotypes. Whilst only 2.3% of E. coli isolates produced enterohaemolysin, 25% were found to produce alpha-haemolysin. CONCLUSIONS: Diverse non-VTEC populations of E. coli serotypes are shed in cattle faeces and diet may affect population diversity. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides new information on the serotype diversity and phenotypic traits of predominant E. coli populations in cattle faeces, which could be sources of environmental contamination.

Animal Feed↗

Hybridization patterns of Actinobacillus actinomycetemcomitans serotypes a-e detected with an rRNA gene probe.

This study reports a genetic characterization of Actinobacillus actinomycetemcomitans strains in relation to serotypes by using rRNA gene restriction patterns. Eighty-eight clinical strains were isolated from 20 unrelated subjects at one or several occasions. The strains were serotyped by using serotype-specific rabbit antisera against serotypes a, b, c, d or e. Three subjects harbored 2 A. actinomycetemcomitans serotypes, 15 subjects 1 serotype and 2 subjects untypable strains. Chromosomal DNA was digested with restriction endonuclease ClaI, BamHI, BglI or HindIII and hybridized to the rrnB ribosomal RNA operon of the Escherichia coli chromosome. Isolates belonging to the same serotype were genetically identical in the same individual but nonidentical if they belonged to different serotypes. Isolates of the same or different serotypes were genetically nonidentical in different individuals. The banding patterns of A. actinomycetemcomitans isolates recovered from the same individuals during several years always remained identical. The hybridization method using pKK3535 as a probe seemed suitable as an epidemiological tool for comparing the clonal identity of A. actinomycetemcomitans strains.

Adolescent↗

Severity of rotavirus infection in relation to serotype, monotype and electropherotype.

The aim of this study was to determine whether the severity of symptoms associated with rotavirus infection was related to the serotype of the infecting virus. Severity of clinical symptoms in 108 children admitted to hospital for treatment of rotavirus diarrhoea was retrospectively assessed using a scoring system for frequency and duration of vomiting and diarrhoea, degree of fever, acidosis and dehydration, and presence of electrolyte imbalance. Children were 6-30 months old and were fully weaned at onset of symptoms prior to admission to hospital. No other enteric pathogens were detected during the course of the illness. Serotypes and monotypes were identified using a panel of monoclonal antibodies. Gel electrophoresis of rotavirus RNA was performed to determine electropherotypes. Children surveyed were infected with serotype 1 (47), serotype 2 (15) or serotype 4 (46) rotaviruses. Comparisons of severity of clinical symptoms according to infecting serotype revealed no statistically significant differences between serotype 1, 2 or 4 infections. In addition, no differences were detected between different rotavirus strains within each serotype (as judged by electropherotype) including monotypes 1a or 1c. This study failed to reveal differences in virulence between rotavirus strains of different VP7 serotypes infecting young children.

Child, Preschool↗

Immunochemical characterization of two new O serotypes of Serratia marcescens (O27 and O28).

In an earlier study of the distribution of O-serotypes among clinical isolates of Serratia marcescens, two apparently new serotypes were identified, represented by strains S1254 and S3255. Studies using ELISA, immunoblotting and the Quellung reaction have shown that they qualify for inclusion in the O-antigenic typing scheme on three counts: (1) they possess chemically distinct O-antigenic repeating units, (2) the O-antigens are serologically distinguishable from all others, and (3) they are found in a significant proportion of clinical S. marcescens strains (13% and 6% respectively). S1254, the type strain for serotype O27, is an acapsular strain which expressed a glucorhamnan with a disaccharide repeating unit as its lipopolysaccharide side chain. It cross-reacts with serotype O4, the O antigen of which is an O-acetylated form of the O27 glucorhamnan, but this cross-reaction can be eliminated by reciprocal cross-absorption. S3255, the type strain for serotype O28, has a mannose homopolymer as its O-antigen and is the only S. marcescens serotype with a trimeric repeating-unit structure. However, it cross-reacts with the O5 serotype strain due to similarities in their acidic capsular polysaccharides. Cross-absorption and the production of serum to an acapsular variant of serotype strain O28 produced typing reagents which could differentiate serotypes O5 and O28.

Carbohydrate Sequence↗

Occurrence of [copper, zinc]-cofactored superoxide dismutase in Pasteurella haemolytica and its serotype distribution.

Fifty-two ovine strains of Pasteurella haemolytica and P. trehalosi representing serotypes 1-16 were examined for the presence of [copper, zinc]superoxide dismutase DNA sequences. This was done using a combination of polymerase chain reaction with degenerate primers based on the sequence of the [Cu,Zn]superoxide dismutase gene (sodC) in related species and Southern hybridization using a fragment of sodC from P. haemolytica A2 serotype as a probe. Both detection methods identified a fragment of the sodC gene in 9/9 strains of P. haemolytica serotype 2 examined and in 5/8 strains of serotype 7. No evidence of this gene was found in any other serotype of P. haemolytica or in any P. trehalosi serotype. Comparison of DNA sequence showed near identity between sodC from the A2 and A7 serotypes of P. haemolytica and substantial similarity (70%) to sodC previously sequenced in P. multocida, Haemophilus parainfluenzae and H. influenzae. Analysis by gel electrophoresis of the superoxide dismutase activity present in cell lysates showed that one or more superoxide dismutase is present in all serotypes. However, cyanide-inhibitable activity, corresponding to [Cu,Zn]superoxide dismutase, was detected only in those strains of serotypes A2 and A7 which showed evidence of the sodC gene fragment.

Amino Acid Sequence↗

Human antibody responses to outer envelope antigens of Porphyromonas gingivalis serotypes.

Immunological studies examining the homogeneity of the major antigenic components of P. gingivalis have suggested 3 serotypes and have indicated a limited distribution of the serotypes in an individual patient. These studies prompted us to define the immunodominant antigens and distribution of immune responses to P. gingivalis serotypes. Serum IgG antibody levels in periodontitis patients in the present study were most frequently elevated above the normal subjects when tested against P. gingivalis serotype A (i.e., 33277). Nearly 1/3 of the patients showed significantly elevated antibody to multiple serotypes of the P. gingivalis apparently resulting from cross-reacting antigens. We determined distinctive differences among outer envelope protein and antigen patterns obtained from the three serotypes. Moreover, the results identified considerable similarities in the qualitative and quantitative antigen response patterns among patients to a particular serotype. There was a strong positive correlation between IgG antibody levels (ELISA) and the total level of reactivity determined in the immunoblots, as well as a positive correlation to the proportion of antibody to particular antigens. These findings suggest that responses to these antigens comprised a major portion of the response to the intact microorganism. Additionally, the detection of antibody to particular antigen bands was indicative of early responses to each of the P. gingivalis serotypes. The results of our study indicate that a subpopulation of periodontitis patients develop an extensive serum antibody response often to multiple serotypes of P. gingivalis and may define a patient population with a P. gingivalis disease. Finally, our results indicate a more consistent antigenic composition for P. gingivalis which may enhance the potential for strategies to immunologically interfere with disease caused by this microorganism.

Adolescent↗

Serotypes of Erysipelothrix rhusiopathiae in Australian pigs, small ruminants, poultry, and captive wild birds and animals.

Serotypes of 93 Australian isolates of Erysipelothrix rhusiopathiae from diseased domestic animals and poultry and a variety of captive wild birds and animals were determined by double diffusion gel precipitation. Two isolates, from the faeces of a swallow were also examined. Serotypes 1a, 1b and 2 were isolated from pigs and serotypes 1a, 1b, 2, 5, 15 and 21 from sheep or goats. Erysipelas in poultry was attributed to serotypes 1b, 5, 15 and 16. In captive wild birds serotypes 1b, 5, 6, 8, 14, 21 and an isolate reactive with antiserum to strain Seehecht were associated with septicaemic deaths. Single isolates from tissues of a bilby (Macrotis lagotis), black rat (Rattus rattus), brown snake (Pseudechis australis) and a bandicoot (Isoodon macrouris) were classified as serotypes 4, 4, 7, and 10 respectively. Six isolates were not able to be typed. Serotype 1b was the most widely distributed and most common (28%), being associated with disease in pigs, sheep, poultry and wild birds. Serotypes 1a or 2 were found in a more restricted range of animals, being commonly associated with erysipelas in pigs, less commonly in sheep and infrequently in other species. From diseased pigs, 26 of 33 isolates (79%) were serotypes 1a and 1b.

Animals↗

Effect of C-reactive protein on the complement-mediated stimulated of human neutrophils by Streptococcus pneumoniae serotypes 3 and 6.

C-reactive protein (CRP) has long been known to appear in the sera of individuals with inflammatory processes, but its role in host defense against bacterial infection is unclear. We have recently demonstrated that CRP in the presence of the classical complement pathway markedly enhances the opsonization of Streptococcus pneumoniae serotype 27 by polymorphonuclear leukocytes (Edwards et al., J. Immunol. 128:2493-2496). In this report we have extended these studies to characterize the role of CRP in the opsonization of other S. pneumoniae serotypes. Two clinically important serotypes, 3 and 6, were tested along with the nonpathogenic rough strain R36a. All strains were found to bind radiolabeled CRP in the presence of calcium and to activate the classical complement pathway in normal human serum. However, the opsonophagocytic response of polymorphonuclear leukocytes to the strains, measured by chemiluminescence, was quite different. In contrast to the marked enhancement by CRP of the chemiluminescent response to serotype 27 in normal human serum, CRP had no effect on the opsonization of serotype 6 or R36a and inhibited opsonization of serotype 3 in normal serum. In serum from a hypogammaglobulinemic patient, CRP enhanced the lowered chemiluminescent response to serotype 3 and 6 organisms but did not restore the response to normal. The greater opsonic effect of CRP on serotype 27 may be related to the ability of CRP to bind to the capsule as well as to the cell wall of this serotype or to differences in the amount of CRP bound to the different strains.

C-Reactive Protein↗

Comparison of the cytolysin II genetic determinants of Actinobacillus pleuropneumoniae serotypes.

Cytolysins (Cly) I, II, and III are toxins secreted by Actinobacillus pleuropneumoniae. These toxins are thought to play an important role in the pathogenesis of porcine pleuropneumonia. ClyI and ClyII are RTX toxins and in general these toxins are encoded by operons consisting of four genes, C, A, B, and D. Our group recently cloned the C and A genes of the ClyII operon (clyIICA) of serotype 9. We found that this ClyII operon is truncated and lacked intact B and D genes (clyIIBD). B and D genes of the ClyI operon (clyIBD) were present however in serotype 9. In this study we analyzed the ClyII operons of the reference strains of the 12 A. pleuropneumoniae serotypes and compared them with the ClyII operon of serotype 9. We focused on (i) the presence, (ii) the sequence similarity, and (iii) the genomic environment of the clyIICA genes. The presence of the clyIICA sequences was studied by hybridization analysis of genomic DNA. The sequence similarity was studied by restriction fragment analysis on polymerase chain reaction-amplified DNA. The genomic environment was compared by analysis of the sequences that are located 3' of the clyIICA genes. We demonstrated that the clyIICA genes (i) are present in the reference strains of all serotypes, except serotype 10, (ii) have a high degree of sequence similarity, and (iii) are not contiguous with intact clyIIBD genes. We conclude that the organization and nucleotide sequence of the ClyII operons of A. pleuropneumoniae are very similar. We also studied the presence of clyIBD sequences and found them to be present in the reference strains of all serotypes, except serotypes 3 and 6. Thus, in most serotypes the clyIBD genes may complement the absent clyIIBD genes.

Actinobacillus pleuropneumoniae↗

Serotype diversity and antigen variation among invasive isolates of Ureaplasma urealyticum from neonates.

Ureaplasma urealyticum has previously been isolated from the cultured cerebrospinal fluid of 13 of 418 newborn infants; additional bloodstream isolates were obtained from the same population. Ten of the 13 cerebrospinal fluid and 3 bloodstream isolates were available for serotyping in the present study. By the use of serotype-specific reagents, including monoclonal antibodies, 70% of the cerebrospinal fluid isolates were identifiable as serotype 1, 3, 6, 8, or 10; i.e., they represented 5 of the 14 established serotypes or both presently defined genomic clusters. One of the bloodstream isolates was identified as serotype 3. Our data support the hypothesis that the property of invasiveness for unreaplasmas is likely not limited to one or a few particular serotypes among the 14 established serovars. Additionally, our study has shown that even in isolates of the same serotype, there can be size variation in the antigens expressed. Therefore, it would appear that many serotypes are invasive and that perhaps antigen variability and host factors may be more important determinants for ureaplasma infections than different serotypes per se.

Animals↗

Characterization of the antigenic lipopolysaccharide O chain and the capsular polysaccharide produced by Actinobacillus pleuropneumoniae serotype 13.

Serotyping of Actinobacillus pleuropneumoniae, the etiologic agent of porcine pleuropneumonia, is important for epidemiological studies and for the development of homologous vaccine cell preparations. The serology is based on the specific chemical structures of capsular polysaccharides (CPSs) and lipopolysaccharide (LPS) antigenic O-polysaccharide moieties (O-PSs), and knowledge of these structures is required for a molecular-level understanding of their serological specificities. The structures of A. pleuropneumoniae serotype 1 to 12 CPSs and O-PSs have been elucidated; however, the structures associated with three newly proposed serotypes (serotypes 13, 14, and 15) have not been reported. Herein we described the structures of the antigenic O-PS and CPS of A. pleuropneumoniae serotype 13. The O-PS of the A. pleuropneumoniae serotype 13 LPS is a polymer of branched tetrasaccharide repeating units composed of l-rhamnose, 2-acetamido-2-deoxy-d-galactose, and d-galactose residues (1:1:2). By use of hydrolysis, methylation, and periodate oxidation chemical methods together with the application of one- and two-dimensional 1H and 13C nuclear magnetic resonance spectroscopy and mass spectrometry, the structures of the O chain and CPS were determined. The CPS of A. pleuropneumoniae serotype 13 was characterized as a teichoic-acid type polymer. The LPS O antigen was identical to the O-PS produced by A. pleuropneumoniae serotype 7. The CPS has the unique structure of a 1,3-poly(glycerol phosphate) teichoic acid type I polymer and constitutes the macromolecule defining the A. pleuropneumoniae serotype 13 antigenic specificity.

Actinobacillus pleuropneumoniae↗

Structural characterization of a specific glycopeptidolipid containing a novel N-acyl-deoxy sugar from mycobacterium intracellulare serotype 7 and genetic analysis of its glycosylation pathway.

The nontuberculous Mycobacterium avium-Mycobacterium intracellulare complex (MAC) is distributed ubiquitously in the environment and is an important cause of respiratory and lymphatic disease in humans and animals. These species produce polar glycopeptidolipids (GPLs), and of particular interest is their serotype-specific antigenicity. Structurally, GPLs contain an N-acylated tetrapeptide-amino alcohol core that is glycosylated at the C terminal with 3,4-di-O-methyl rhamnose and at the d-allo-threonine with a 6-deoxy-talose. This serotype nonspecific GPL is found in all MAC species. The serotype-specific GPLs are further glycosylated with a variable haptenic oligosaccharide at 6-deoxy-talose. At present, 31 distinct serotype-specific GPLs have been identified on the basis of oligosaccharide composition, and the complete structures of 14 serotype-specific GPLs have been defined. It is considered that the modification of the GPL structure plays an important role in bacterial physiology, pathogenesis, and host immune responses. In this study, we defined the complete structure of a novel serotype 7 GPL that has a unique terminal amido sugar. The main molecular mass is 1,874, and attached to the tetrapeptide-amino alcohol core is the serotype 7-specific oligosaccharide unit of 4-2'-hydroxypropanoyl-amido-4,6-dideoxy-2-O-methyl-beta-hexose-(1-->3)-alpha-l-rhamnose-(1-->3)-alpha-l-rhamnose-(1-->3)-alpha-l-rhamnose-(1-->2)-alpha-l-6-deoxy-talose. Moreover, we isolated and characterized the serotype 7-specific gene cluster involved in glycosylation of the oligosaccharide. Nine open reading frames (ORFs) were observed in the cluster. Based on the sequence homology, the ORFs are thought to participate in the biosynthesis of the serotype 7 GPL.

Carbohydrate Sequence↗

Distribution and invasiveness of Streptococcus pneumoniae serotypes in Switzerland, a country with low antibiotic selection pressure, from 2001 to 2004.

To describe the serotype-specific epidemiology of colonizing and invasive Streptococcus pneumoniae isolates, which is important for vaccination strategies, we analyzed a total of 2,388 invasive and 1,540 colonizing S. pneumoniae isolates collected between January 2001 and December 2004 within two nationwide surveillance programs. We found that the relative rank orders of the most frequent serotypes (serotypes 1, 3, 4, 6B, 7F, 14, 19F, and 23F) differed among invasive and colonizing isolates. Serotypes 1, 4, 5, 7F, 8, 9V, and 14 had increased invasive potential, and serotypes/serogroups 3, 6A, 7, 10, 11, 19F, and 23F were associated with colonization. The proportion of pediatric serotypes was higher among children < 5 years old (48.5%) and persons > 64 years old (34.1%) than among other age groups (29.1%); it was also higher in West Switzerland (40.2%) than in other geographic regions (34.7%). Likewise, serotype-specific proportions of penicillin-resistant isolates for types 6B, 9V, 14, and 19F were significantly higher in West Switzerland. The relative frequency of pediatric serotypes corresponded with antibiotic consumption patterns. We conclude that the epidemiology of invasive and colonizing S. pneumoniae isolates is influenced by the serotype-specific potential for invasiveness, and therefore, surveillance programs should include colonizing and invasive S. pneumoniae isolates. Antibiotic selection pressure determines the serotype distribution in different age groups and geographic regions and therefore the expected direct and indirect effects of the 7-valent conjugate vaccine.

Adolescent↗

Serotyping Cryptococcus neoformans by immunofluorescence.

Four serotypes of Cryptococcus neoformans designated A, B, C, and D are currently recognized. Although an agglutination test is most often used to serotype C. neoformans in cultures, this test is not appropriate for typing the fungus in fixed tissues. A study to prepare fluorescent-antibody reagents for typing C. neoformans in cultures and to determine whether they can be used to type this fungus in fixed tissues was carried out. Antisera to one strain belonging to each of the four serotypes were prepared in rabbits by intravenous injection of whole Formalin-killed cryptococci. Each antiserum was labeled with fluorescein isothiocyanate and then adsorbed with cells of each of the heterologous serotypes. The adsorbed conjugates were then tested against six serotype A isolates and five isolates of each of the other three serotypes. Labeled serotype A or D antiserum adsorbed with either B or C cells stained the A and D, but not the B or C, isolates. Labeled serotype B antiserum adsorbed with A cells stained the B and C, but not the A or D, isolates. Labeled A antiserum absorbed with D cells differentiated A from D; labeled C antiserum absorbed with B cells differentiated C from B. Of the 21 test isolates, 17 could be serotyped in paraffin sections of tissues of experimentally infected mice.

Animals↗

Serotyping of Campylobacter jejuni isolated from sporadic cases and outbreaks in British Columbia.

Campylobacter jejuni from sporadic cases and outbreaks of gastroenteritis were serotyped on the basis of heat-extracted soluble thermostable antigens identified with the use of the passive hemagglutination technique. A total of 168 isolates were separated into 45 different types. The largest proportion of the isolates fell into three serotypes, each with 11 to 12.5% of the total number. Three less frequently occurring serotypes each included approximately 5%, and the remaining 50% of the isolates were distributed among 39 other serotypes. In most cases, serotyping demonstrated that epidemiologically linked isolates were of the same serotype, but the outbreak strains could belong either to frequently or to infrequently isolated serotypes. The high correlation between clinical findings and serotyping results confirmed the applicability of the serotyping scheme in epidemiological investigations of C. jejuni infections.

British Columbia↗