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Invasive meningococcal disease in children in Greece: comparison of serogroup A disease with disease caused by other serogroups.

Although invasive meningococcal disease caused by serogroup A is not prevalent in developed countries, a considerable number of cases were recently recorded in Greece. In this study, serogroup A meningococcal disease was compared prospectively with meningococcal disease caused by other serogroups, using similar settings of testing and management during a 5-year period between 1999 and 2003. The Neisseria meningitidis serogroup was determined in 262 cases. Serogroup B predominated, accounting for 158 (60%) of the cases. Serogroup A was second most frequent (19%), followed by serogroups W135 (11%), C (8%), and Y (2%). No cases due to serogroup C were recorded during the last year of the study. Patients with serogroup A disease were older and had a milder course compared to patients infected with serogroups B or C. Toxic appearance, purpura, thrombocytopenia, abnormal coagulation tests, and the need for admission to the intensive care unit, fluid resuscitation, inotropic drugs, and mechanical ventilation were less common. Although morbidity and mortality were lower in these patients, the differences were not significant. Serogroup B is predominant in our area, and the introduction of an effective vaccine against it is a priority. Serogroup A has emerged as the second most common serogroup, but the illness associated with it is milder.

Adolescent↗

Serological specificities of murine hybridoma monoclonal antibodies against Neisseria meningitidis serogroups B, C, Y, and W135 and evaluation of their usefulness as serogrouping reagents by indirect whole-cell enzyme-linked immunosorbent assay.

Murine hybridoma monoclonal antibodies (MAbs) were produced against the capsular antigens of serogroups B, C, Y, and W135 meningococci. Each serogroup-specific MAb reacted with the extracted capsular polysaccharide from its homologous serogroup only and did not react with capsules from the other three serogroups. The application of these MAbs for serogroup identification of meningococci was demonstrated by their abilities to correctly identify 183 clinical isolates of 185 meningococci recovered from individual invasive meningococcal disease (IMD) patients during routine surveillance in 2002. The remaining two meningococci were identified by PCR grouping as C in one case and Y in another, but neither isolate was positive by bacterial agglutination using rabbit antisera or by enzyme-linked immunosorbent assay using MAbs. The specificities of the anti-Y and anti-W135 MAbs were further assessed by tests with 37 serogroup W135 and 106 serogroup Y meningococci recovered from IMD cases during 1999 to 2001 and 2003. All 143 meningococci except one serogroup Y isolate were correctly identified by positive reactions with the corresponding MAbs that identified their homologous serogroups. The single serogroup Y isolate was received as nonagglutinable and tested as negative with both rabbit anti-Y antiserum and anti-Y MAb but was positive for the serogroup Y-specific siaD gene. The advantage of using MAbs for serogrouping of meningococci is discussed.

Animals↗

Intra- and inter-serogroup genetic relatedness of orbiviruses. I. Blot hybridization of viruses of Australian serogroups.

Viruses in the Eubenangee, Wallal and Warrego serogroups of orbiviruses have been isolated primarily in Australia. Several isolates in these three serogroups were examined by gel electrophoresis and blot hybridization of genomic RNA. Conserved and variant genes were identified by the degree of hybridization between cognate genes. The dsRNA profiles of isolates within a serogroup exhibited heterogeneity in polyacrylamide gels, but they were indistinguishable in agarose gels. Isolates within a serogroup generally showed a high level of cross-hybridization in eight segments with cognate segments 2 and 6 exhibiting hybridization signal variants. Although Pata virus has been classified in the Eubenangee serogroup, it was not closely related to other Eubenangee isolates by hybridization. Similarly, Mitchell River virus was not closely related to other members of the Warrego serogroup. The taxonomic status of Pata and Mitchell River viruses should be reviewed, and in the interim they should be placed in the ungrouped set of orbiviruses. Inter-serogroup relatedness was also examined by blot hybridization. Representatives from the Eubenangee, Wallal, Warrego, bluetongue, epizootic haemorrhagic disease and Corriparta serogroups were examined. Several of the serogroups were distantly related, and the low level of relatedness was suggestive of a common ancestry. While many of these serogroups may co-circulate in nature, these data suggest that each serogroup represents a distinct gene pool. The taxonomic significance of these data is discussed.

Animals↗

Intra- and inter-serogroup genetic relatedness of orbiviruses. II. Blot hybridization and reassortment in vitro of epizootic haemorrhagic disease serogroup, bluetongue type 10 and Pata viruses.

Viruses which belong to the epizootic haemorrhagic disease (EHD), bluetongue and Eubenangee serogroups of orbiviruses exhibit low level cross-reactions in some serological tests. Although Pata virus cross-reacts at low levels with members of the EHD and bluetongue serogroups, it was assigned originally to the Eubenangee serogroup. RNA-RNA blot hybridization data, however, suggest that Pata virus is not a member of the Eubenangee serogroup. In this study, the genetic relatedness of the EHD serogroup viruses, bluetongue virus type 10 (BTV-10) and Pata virus was assessed by RNA-RNA blot hybridization and by gene reassortment experiments in vitro. The five members of the EHD serogroup examined were highly related by reciprocal RNA RNA blot hybridization. Genes 1, 3, 4 and 6 to 9 were highly conserved with three unique types of gene 2, four variant types of gene 5 and two variant types of gene 10. Geographical boundaries could not be correlated with sequence relatedness because viruses isolated from the same locality were distant relatives when compared with another virus isolated on a different continent. The significance of the unique and variant genes is discussed. The EHD isolates, BTV-10 and Pata virus exhibited distinct profiles on agarose and polyacrylamide gel electrophoresis, and they are related distantly as shown by weak hybridization signals in blot hybridization. Gene 2 was a unique gene among the EHD isolates, BTV-10 and Pata virus. One BTV-10 gene hybridized more strongly to gene 9 of the EHD viruses than the other BTV-10 genes, and its role in encoding the cross-reactive antigen is discussed. Intra-serogroup gene reassortment in vitro was demonstrated in the six crosses among EHD serogroup members. In contrast, gene reassortment was not observed in inter-serogroup crosses between EHD 1 and BTV-10, BTV-10 and Pata virus, and between EHD 1 and Pata virus. Correlation of blot hybridization and gene reassortment indicated that viruses must share high sequence conservation in the majority of their genes before genetic interaction is likely. The usefulness of blot hybridization as an indicator of the likelihood of gene reassortment is discussed. These hybridization and gene reassortment data indicated that Pata virus is not a member of the bluetongue or EHD serogroups and that it should be assigned to the ungrouped set of orbiviruses. The hybridization and gene reassortment data suggest that members of the EHD serogroup, BTV-10 and Pata virus represent three distinct gene pools, and the role of reassortment in the generation of genetic diversity is discussed.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Nucleotide sequence and deduced amino acid sequence of the medium RNA segment of Oropouche, a Simbu serogroup virus: comparison with the middle RNA of Bunyamwera and California serogroup viruses.

The Bunyavirus genus of the family Bunyaviridae contains 18 serogroups. To date nucleotide sequence data has been obtained for three serogroups, Bunyamwera, California and Simbu, based on analysis of the small (S) RNA segment. In comparison, there is only nucleotide sequence data for the large and medium (M) RNA segments for members of the Bunyamwera and California serogroups. In this paper we report the nucleotide sequence of the M RNA of Oropouche (ORO) virus, a member of the Simbu serogroup. The M RNA was 4396 nucleotides in length with G1, G2 and NSm proteins similar in size to those reported for members of the Bunyamwera and California serogroups. However, there was limited nucleotide (50-52%) and amino acid (30-32%) homology between ORO virus M RNA and those of published members of the other two serogroups. The Bunyamwera and California serogroups are more closely related to each other than the Simbu serogroup virus Oropouche. These data were consistent with that previously reported for the S RNA (Saeed et al., 2000. J. Gen. Virol. 81, 743-748). It has been noted previously that three of four potential N-linked glycosylation sites of the Bunayamwera and California serogroups are conserved in G1 and G2 proteins. In contrast, ORO virus was found to have only three potential N-linked glycosylation sites of which only one, in G1, was conserved with members of the other two serogroups. Comparison of M RNA sequences of different strains of ORO virus revealed genetic variation consistent with that reported previously for the S RNA.

Amino Acid Sequence↗

Serogroup-specific and serogroup-cross-reactive epitopes of Legionella pneumophila.

A panel of monoclonal antibodies was used to serotype 343 Legionella pneumophila isolates, using the indirect immunofluorescence test and ELISA. In addition, the isolates were typed by means of absorbed rabbit antisera to provide a reference procedure. As shown by a comparison of reaction patterns, serogroup-specific monoclonal antibodies were found for serogroups 1, 2, 3, 4, 6, 7, 8, and 10. Monoclonal subtypes were found to exist within serogroups 1, 2, 5, and 6. Using the monoclonal antibody panel introduced for serogroups 1 to 8 and 10, it was possible to serotype or subtype 92% of the isolates tested. The remaining isolates belonged to serogroups 9, 11 to 14 and to a monoclonal subtype of serogroup 5. 8 monoclonal antibodies recognized serogroup-cross-reactive epitopes. Except for serogroups 1, 7, and 11, all others shared a common antigenic determinant. Another common epitope was shared by strains of serogroups 2 and 3. Additional cross-reactivity was associated in particular with strains of serogroups 5, 8, and 10.

Animals↗

[The production and identification of partial serogroup--specific monoclonal antibodies against leptospires hebdomadis serogroup].

Hebdomadis is one of the major serogroups found in China. In Sichuan, this serogroup appears to have a close relationship with local outbreak of leptospirosis. BALB/c mice were immunized intrasplenically with outer envelope of serogroup Hendomadis serovar hebdomadis strain 245. Spleen cells were fused with SP2/0 myeloma cells, two monoclonal antibodies Af2 and Bb2 were produced by hybridoma technique. McAb Af2 and McAb Bb2 were identified to be IgG1 and IgG3 by immunodiffusion respectively. Specificities of these two McAbs were determined by MAT; both reacted to 8 serovars (hebdomadis, nona, kambale, kremastos, worsfoldi, jules, maruborincana) of Hebdomadis serogroup. The agglutination titres of McAb Af2 and McAb Bb2 were 1:640-1:2,500,000 and 1:320-1:2,500,000, respectively. The two McAbs did not agglutinate with serovar kabura of Hebdomadis serogroup, they did not agglutinate with 11 serovars of Sejroe serogroup, 4 serovars of Mini serogroup, 18 representive serovars of L. interrogans in 18 serogroups, L. biflexa strain Patoc I and Leptonema illini. So it was found that McAb Af2 and McAb Bb2 showed partial serogroup specificity for Hebdomadis by agglutination.

Animals↗

Immunologic hyporesponsiveness to serogroup C but not serogroup A following repeated meningococcal A/C polysaccharide vaccination in Saudi Arabia.

In Saudi Arabia, vaccination with the meningococcal A/C polysaccharide (MACP) vaccine is advised every 3 years. A clinical outcome study was performed to test the effect of repeat vaccination with the MACP vaccine on the immune responses among Saudi nationals who live in the Makkah and Jeddah areas. Subjects (n = 230) aged 10 to 29 years were selected: 113 subjects with two or more prior vaccinations with the MACP vaccine, 79 subjects with one prior vaccination with the MACP vaccine, and 38 subjects naïve to vaccination with the MACP vaccine. All subjects received the MACP vaccine in 2002, and serum bactericidal antibody (SBA) titers were measured before and 1 month after vaccination with the MACP vaccine. For serogroup C, geometric mean SBA titers 1 month following vaccination with the MACP vaccine were 708.6 (95% confidence interval [CI], 217.5 to 2,308.9) for those naïve to prior vaccination with the MACP vaccine, and they were significantly higher (P < 0.0001) than 25.0 (95% CI, 12.4 to 50.2) for those who had received one prior vaccination with the MACP vaccine and 32.4 (95% CI, 18.7 to 56.4) for those who had received two or more doses of the MACP vaccine. For serogroup A, the geometric mean SBA titer 1 month after receipt of the MACP vaccine was 1,649.3 (95% CI, 835.2 to 3,256.9) for those naïve to prior vaccination, and the titers were lower (P = 0.67) than 2,185.7 (95% CI, 1,489.4 to 3,207.7) for those who had received one prior dose of the MACP vaccine and significantly lower (P = 0.042) than 3,540.8 (95% CI, 2,705.2 to 4,634.5) for those who had received two or more doses of the MACP vaccine. For serogroup C, the proportions of nonresponders (SBA titers, <8) were 19% for the naïve cohort, 52% for the cohort with one prior vaccination, and 49% for the cohort with two or more prior vaccinations. Following repeated doses of the MACP vaccine, hyporesponsiveness to serogroup C is evident, with high percentages of MACP vaccinees having SBA titers below the putative protective SBA titer. Serogroup A responses following vaccination with the MACP vaccine were boosted. Introduction of the serogroup C conjugate vaccine would provide long-term protection against serogroup C disease; however, quadrivalent conjugate vaccines are required to provide long-time protection against disease caused by serogroups A, W135, and Y.

Adolescent↗

Prevalence of de-O-acetylated serogroup C meningococci before the introduction of meningococcal serogroup C conjugate vaccines in the United Kingdom.

Meningococcal serogroup C conjugate (MCC) vaccines have been introduced in the UK to combat the rise in serogroup C meningococcal disease. Serogroup C meningococci may occur naturally expressing either O-acetylated (Oac(+)) or de-O-acetylated (Oac(-)) polysaccharide capsules. In a small study in the USA in the 1970s 15% of serogroup C meningococcal case isolates were reported to be Oac(-) though the prevalence of these Oac(-) isolates has not been recorded in the UK. This is of interest as the first MCC vaccines to be introduced are Oac(+) and the potential impact of this on Oac(-) serogroup C isolates is unclear. Serogroup C isolates submitted to the Public Health Laboratory Service Meningococcal Reference Unit in January 1998 (n=113) and January 1999 (n=162) were investigated by dot blotting using monoclonals specific for Oac(+) and Oac(-) serogroup C polysaccharides. This revealed 12% Oac(-) isolates for both January 1998 and January 1999. The proportion of fatal cases was found to similar for both Oac(-) and Oac(+), 14 and 9% for 1998 and 5 and 3% for 1999, indicating that the pathogenic potential of these Oac(-) isolates is similar to Oac(+). The acetylation status of serogroup C isolates needs to be monitored throughout and after the introduction of MCC vaccines.

Antibodies, Monoclonal↗

Serogrouping of Neisseria gonorrhoeae: correlation of serogroup with disseminated gonococcal infection.

Gonococci can be divided into serogroups WI, WII, and WIII by coagglutination. To assess the clinical correlation of serogroups of gonococci, we studied isolates of gonococci from patients with disseminated and uncomplicated gonococcal infections in three cities in the United States. Strains of Neisseria gonorrhoeae belonging to serogroup WI represented 85 (84%) of 101 isolates from patients with disseminated gonococcal infection (DGI) and 68 (40%) of 168 isolates from patients with uncomplicated gonorrhea (P less than .001). The auxotype Arg-, Hyx-, Ura- (AHU) represented 62 (61%) of 101 isolates from DGI and 54 (32%) of 168 isolates from uncomplicated infection (p less than .001); all AHU isolates were serogroup WI. Among other auxotypes, WI strains represented 25 (64%) of 39 isolates from patients with DGI and 14 (12%) of 114 from uncomplicated infections (P less than .001). In Atlanta only, 13 (34%) of 38 isolates from DGI were AHU, but 31 (82%) were serogroup WI (P less than .001). Thus gonococci of serogroup WI are associated with DGI in these cities of the United States, and this correlation appears to be independent of auxotype. Serogroup WI is correlated with serum resistance.

Black People↗

Molecular analysis of the rfb O antigen gene cluster of Salmonella enterica serogroup O:6,14 and development of a serogroup-specific PCR assay.

The Kauffmann-White scheme for serotyping Salmonella recognizes 46 somatic (O) antigen groups, which together with detection of the flagellar (H) antigens form the basis for serotype identification. Although serotyping has become an invaluable typing method for epidemiological investigations of Salmonella, it does have some practical limitations. We have been characterizing the genes required for O and H antigen biosynthesis with the goal of developing a DNA-based system for the determination of serotype in Salmonella. The majority of the enzymes involved in O antigen biosynthesis are encoded by the rfb gene cluster. We report the sequencing of the rfb region from S. enterica serotype Sundsvall (serogroup O:6,14). The S. enterica serotype Sundsvall rfb region is 8.4 kb in length and comprises six open reading frames. When compared with other previously characterized rfb regions, the serogroup O:6,14 sequence is most related to serogroup C(1). On the basis of DNA sequence similarity, we identified two genes from the mannose biosynthetic pathway, two mannosyl transferase genes, the O unit flippase gene and, possibly, the O antigen polymerase. The whole cluster is derived from a low-G+C-content organism. Comparative sequencing of an additional serogroup O:6,14 isolate (S. enterica serotype Carrau) revealed a highly homologous sequence, suggesting that O antigen factors O:24 and O:25 (additional O factors associated with serogroup O:6,14) are encoded outside the rfb gene cluster. We developed a serogroup O:6,14-specific PCR assay based on a region of the putative wzx (O antigen flippase) gene. This provides the basis for a sensitive and specific test for the rapid identification of Salmonella serogroup O:6,14.

Bacterial Proteins↗

Neisseria meningitidis serogroup C polysaccharide and serogroup B outer membrane vesicle conjugate as a bivalent meningococcus vaccine candidate.

Neisseria meningitidis serogroup C polysaccharide (PS C) was conjugated to serogroup B outer membrane vesicles (OMV) in order to test the possibility of obtaining a bivalent group B and C meningococcus vaccine. The conjugate and controls were injected intraperitoneally into groups of ten mice with boosters on days 14 and 28 after the primary immunization. The following groups were used as control: (i) PS C; (ii) PS C plus OMV; (iii) OMV; and (iv) saline. The serum collected on days 0, 14, 28 and 42 were tested by enzyme-linked immunosorbent assay (ELISA) for PS C and OMV, and by complement mediated bactericidal assay against serogroups B and C. ELISA for PS C as well as bactericidal titres against serogroup C meningococci of the conjugated vaccine increased eight-fold (ELISA) and 32 fold (bactericidal) after 42 days in comparison with the PS C control group. ELISA for OMV and bactericidal titre against serogroup B meningococci of the conjugate showed no significant difference in comparison with the OMV containing controls. Furthermore, Western Blot assay of the conjugate immune serum did not bind OMV class four protein which is related to the complement dependent antibody suppressor. The results indicate that the PS C-OMV conjugate could be a candidate for a bivalent vaccine toward serogroups B and C meningococci.

Animals↗

[Distribution of serogroups of Vibrio cholerae non-O1 non-O139 with specific reference to their ability to produce cholera toxin, and addition of novel serogroups].

A total of 1898 strains of Vibrio cholerae non-O1 non-O139, which had been collected worldwide for the past 3 year period of 1994-1996, were serogrouped. The strains were also examined for presence of cholera toxin (CT) gene (ctx) and NAG-ST gene, and strains which carried to ctx were further analyzed for their ability to produce CT. In addition, attempts were made to establish novel serogroups for those serologically untypable strains. Of those examined, 1,774 strains of V. cholerae non-O1 non-O139 was classified into 128 known serogroups while 50 strains were found to belong to R type, and the rest of the 74 strains could not be serotyped. Distribution of the serogroups did not seem to correspond to either the strains geographic distribution or sources of isolation. Of those serologically untypable strains, 38 novel serogroups (O156-O193) were established and added to our reference of V. cholerae antigenic schema. It was also found that antisera raised against many V. cholerae strains included R antibodies. This indicates that any V. cholerae antisera for diagnostic purpose should be absorbed with the reference R strains, CA385, before use. There were luminescence producing strains among those sucrose and VP reaction negative strains. Subsequent DNA/DNA homology analysis revealed that they were identified as V. cholerae. This points to a possibility that strains tentatively identified as Vibrio mimicus by conventional biochemical tests may have included luminescent strains of V. cholerae. It is thus highly recommended that strains in question should be tested for the luminescence production in order to differentiate V. cholerae from V. mimicus. Of those 1989 strains examined, 37 strains (ca. 2%) were found to produce CT. Interestingly, CT producing strains were prevalent in serogroup O141; 10 strains out of 16 strains (63%) were positive for CT. The evidence calls for a caution to possible occurrence of cholera-like diarrhea caused by V. cholerae O141 in the future.

Cholera Toxin↗

[Study on the production, identification of serogroup-specific monoclonal antibodies against leptospires of Australis serogroup and detection of its antigen].

Spleen cells of BALB/c mice immunized with whole Leptospira interrogans serogroup Australis serovar australis strain 620 were fused with myeloma cells line SP2/0. Specificities of four McAbs determined by MAT. 2E1 McAb (IgG3) reacted with 11 serovars, of the Australis serogroup, but did not react with 22 representative serovars of L. interrogans in 20 serogroups, L. biflexa strain patoc I and Leptonema illini strain 3055. 2E1 McAb showed serogroup specificity for Australis by agglutination and the other 3 McAbs showed partial serogroup specificity. We compared the outer envelope (OE) protein profiles of serovar australis strain 620 with those of two pathogenic L. interrogans serovar lai strain 601 and serovar hebdomadis strain 156 by SDS-PAGE. 63kd protein profile was only found in the OE of strain 620, and the quantity of 42kd protein of strain 620 was greater than that of strain 601 and 156. The immunoblotting revealed that 2E1 McAb reacted with a 34kd band in the OE preparation of serovar australis strain 620, but did not react with that of other two L. interrogans. 2E1 McAb also did not react with OE of non-pathogenic leptospires. It was suggested that 34kd protein might contain the antigenic determinants which were shared by leptospires of Australis serogroup.

Animals↗

Polysaccharide vaccines for preventing serogroup A meningococcal meningitis.

BACKGROUND: Controlled trials over two decades ago showed that the polysaccharide vaccine prevented meningococcal meningitis. Subsequent observational studies suggested variations in the level and duration of protection, particularly among young children. OBJECTIVES: To determine the effect of polysaccharide serogroup A vaccine for preventing serogroup A meningococcal meningitis. SEARCH STRATEGY: MEDLINE and the Cochrane Controlled Trials Register. SELECTION CRITERIA: Randomised and other prospective controlled trials. DATA COLLECTION AND ANALYSIS: One reviewer collected data and assessed the methodologic quality of the trials. Data were pooled using the Exact method to assess vaccine efficacy at one, two and three years post-vaccination. MAIN RESULTS: The protective effect within the first year was consistent across all eight trials, including one with participants exclusively under six years of age (in Finland); overall vaccine efficacy was 95% (Exact 95% CI 87%, 99%). The Finnish trial lacked statistical power to assess the effect of a booster dose given to children less than 18 months old. In the three other trials that included children less than six years old (one in Sudan and two in Nigeria), none of the vaccinated children developed meningitis, but the statistical significance of this finding was undetermined. Protection extended into the second (in two studies) and third (in one study) years after vaccination, but these results were also not statistically significant. REVIEWER'S CONCLUSIONS: When compared with current recommendations, the methodological quality and relative incompleteness of the published reports could arguably render the trials invalid for this review. However, it was unlikely that the results of the trials in such diverse settings would have been biased towards a strong and consistent protective effect. Immunogenicity trials were not included in this review. Stage two of the review will assess the vaccine effect from observational studies.

Humans↗

Nucleotide sequence of the pilin gene of Bacteroides nodosus 340 (serogroup D) and implications for the relatedness of serogroups.

The gene encoding pilin of Bacteroides nodosus 340 has been isolated and the nucleotide sequence determined. The gene is present as a single copy within the B. nodosus genome and a protein of Mr 16683 can be predicted from the proposed coding region. A comparison of the predicted amino acid sequence with pilin from other strains of B. nodosus indicated that the protein of strain 340 (serogroup D) has a high degree of similarity with pilin of strain 265 (serogroup H). The degree of similarity between pilins from these strains and from other B. nodosus serogroups is no greater than that between B. nodosus pilins and the homologous proteins of several different bacterial species. These findings suggest that serogroups D and H may form a subset of B. nodosus serogroups.

Amino Acid Sequence↗

Sequence of pilin from Bacteroides nodosus 351 (Serogroup H) and implications for serogroup classification.

The nucleotide sequence of the pilin gene from Bacteroides nodosus strain 351, currently classified as serogroup H, subgroup 2 (H2) has been determined. The gene encodes a single polypeptide (prepilin) of 160 amino acids and Mr 17,150. However, pilin isolated from B. nodosus 351 migrates as two distinct bands in sodium dodecyl sulphate-polyacrylamide gel electrophoresis, due to an internal peptide bond cleavage. Amino acid sequence studies of pilin from B. nodosus 351 have established that the cleavage occurs between 72Ala and 73Ser of the mature protein sequence. Comparisons of gene and amino acid sequences of pilin from B. nodosus 351 with the corresponding sequences from strains of serogroups D and H1 indicate that these sequences share a close relationship. However, the level of sequence identity between B. nodosus 351 pilin and pilin from strain 265 of serogroup H1 is lower than anticipated for strains within a serogroup and suggests that B. nodosus 265 and B. nodosus 351 should not be classified within the same serogroup.

Amino Acid Sequence↗

The wbpM gene in Pseudomonas aeruginosa serogroup O17 resides on a cryptic copy of the serogroup O11 O antigen gene locus.

The Pseudomonas aeruginosa serogroup O11 strain PA103 O antigen gene locus consists of 11 genes designated wzz, wzx, wbjA, wzy, wbjB-F, wbpL, and wbpM. The distribution of each of these genes amongst the 20 P. aeruginosa international antigenic typing system (IATS) serogroups was analyzed by Southern blot. As shown previously, wbpM was present in all 20 serogroups. The remaining O11 O antigen genes, with the exception of wzy, were present in the serogroup O17 strain IATSO17, despite the structural unrelatedness of the O11 and O17 O antigens. Sequencing revealed the presence of a cryptic serogroup O11 locus in the IATSO17 interrupted by two copies of a 1.1-kb insertion element. Introduction of plasmid pLPS2, containing the complete O11 O antigen locus from strain PA103, into IATSO17 resulted in production of both the O11 and O17 O antigens. The results of insertional inactivation of wbpM in IATSO17 are discussed.

Base Sequence↗