OBJECTIVE:To determine the total and functional serogroup C antibody response to a quadrivalent meningococcal polysaccharide vaccine in a group of aboriginal infants, children and adolescents. A secondary objective was to determine their prevalence of meningococcal carriage. DESIGN:Open prospective, before and after intervention study. SUBJECTS:Aboriginal children ages 0.5 to 19.9 years, living in a single Northern community and eligible for a public health immunization campaign conducted in all Manitoba native reserve communities to control a meningococcal serogroup C, electrophoretic type (ET) 15 outbreak. No outbreak cases had occurred in the community at the time of the study. METHODS:Total serogroup C capsular polysaccharide antibody (CPA) and functional bactericidal antibody (BA) responses were measured by enzyme-linked immunosorbent assay and bactericidal assay, respectively. RESULTS:Neisseria meningitidis was recovered from the oropharynx of 13 (5.2%) of 249 aboriginal children including 4 (1.6%) serogroup C isolates, all with the designation C:2a:P1.2,5 ET15. Paired sera from 152 children were available for assay. For CPA the geometric mean concentrations and proportions with > or =2 microg/ml before and after immunization were 0.69, 18% and 12.3, 96%, respectively. A significant increase in serum CPA was achieved by children of all ages, with the greatest response occurring after age 11 years. Among infants < lyear old 89% achieved concentrations of > or =2 microg/ml. For BA the pre- and post-vaccine geometric mean titers were 1.02 and 45.9. The response was significantly associated with age. BA titers > or =1:8 were present, before and after immunization, respectively, in 0 and 0% of infants <1 year old, 0 and 20% of 1- to 1.4-year-olds, 0 and 50% of 1.5- to 1.9-year-olds and 1 and 100% of > or =2-year-olds. CONCLUSION:The age-related total and functional group C meningococcal antibody response after quadrivalent polysaccharide vaccine among aboriginals is similar to that reported for Caucasian children. After age 2 all children made excellent CPA and BA responses. In the younger age groups the BA response was blunted but 82 to 95% achieved CPA titers of > or =2 microg/ml.

Invasive meningococcal disease is nationally reportable in Canada. In recent years, a serogroup C genotype, designated electrophoretic type 15 (ET15), has been the most frequently isolated meningococcal genotype in Canada and has caused epidemics across the country. Between August 1993 and September 1995, there were 9 cases of invasive meningococcal disease caused by a variant of this genotype, expressing group B capsular polysaccharide. The appearance of serogroup B:ET15 was related temporally and geographically to mass immunization campaigns designed to control serogroup C meningococcal disease in Canada. Since there is no vaccine available to control serogroup B meningococcal disease, the appearance of this variant may have public-health significance if it demonstrates the same epidemic potential as its serogroup C counterpart.

Moderately penicillin-resistant Neisseria meningitidis is rare in North America. We report an outbreak of meningococcal disease in Saskatoon, Saskatchewan, Canada, with serogroup C N. meningitidis. The MICs of penicillin ranged from 0.12 to 0.25 micrograms/ml, and all isolates showing decreased susceptibility had identical genomic fingerprints when they were compared by pulsed-field gel electrophoresis. Our data indicate that N. meningitidis that is moderately resistant to penicillin is prevalent in Saskatchewan, Canada.

Strains of meningococci isolated from patients in South Australia (SA) and the Northern Territory (NT) with either bacteremia or meningitis (or both) were serotyped and serosubtyped using monoclonal antibodies in a whole cell ELISA technique. From SA, 144 isolates were examined for the period 1971 through 1989 and from the NT, 38 isolates from 1975 through 1977 and 1983 through 1989 were examined. During the periods of study the principal serogroups were group B in South Australia and group A in the Northern Territory. About 60% of the SA strains were typable and subtypable: the predominant types were 4, 2a, 15 and 14, in that order; the predominant subtypes were P1.2, P1.1 and P1.10, in that order. Of the strains from the NT about 80% were typable, the predominant type was type 4 and all 19 group A strains were identified as type 4, subtype P1.10.

A single electrophoretic type (ET15) of Neisseria meningitidis has been associated with an increased incidence of group C meningococcal disease in Canada. Genomic fingerprinting through pulsed-field gel electrophoresis of chromosomal DNA was used to characterize the clonal relationship among meningococcal isolates of different electrophoretic types and among isolates within ET15. The genomic fingerprints of the ET15 isolates, while similar as a group, were sufficiently distinct to confirm linkage for four pairs of strains from focal outbreaks and differed markedly from those of the other common electrophoretic types, ET5, ET9, and ET21.

Two pairs of synthetic oligonucleotide primers were used in a polymerase chain reaction (PCR) protocol to detect targeted sequences in genes coding for listeriolysin O and Listeria monocytogenes antigen A (ImaA). Strains of Listeria spp. used in this study were isolated from clinical specimens, contaminated foods, and environmental sources. Primers were targeted to internal regions of the genes coding for listeriolysin (hlyA) and Listeria antigen (ImaA) and amplification fragments were detected after the PCR by agarose gel electrophoresis. PCR was performed using nucleic acids extracted from a collection of 74 strains of Listeria spp. including 18 reference strains, 41 L. monocytogenes, nine L. innocua, five L. seeligeri and one L. ivanovii, encompassing representative sources, serovars, and enzyme electrophoretic types. Although the listeriolysin gene was found exclusively in L. monocytogenes, some strains of serovar 4c were negative. Simultaneous presence of both genes was restricted to L. monocytogenes strains of serovars 1/2, 3, and 4. The ImaA gene was identified in five of 10 L. innocua strains and one L. ivanovii isolated from pork. Strains of L. seeligeri, L. welshimeri, and L. grayi were negative for both genes. The detection limits in the PCR were found to be 10 pg of nucleic acids for the hlyA gene and 1 pg for the ImaA gene.

The presence of genes encoding pyrogenic exotoxins type A (speA), B (speB), and C (speC) and streptolysin O (slo) was determined by the polymerase chain reaction (PCR) to target specific sequences in 152 strains of group A streptococci. These included reference strains, representative M and T type strains, and strains associated with scarlet fever and pharyngitis collected between 1940 to 1991 and included strains from patients with severe invasive streptococcal infections. PCR amplicons were detected by agarose gel electrophoresis, and specificity was established by restriction fragment analysis. The frequency of occurrence for each target gene among all strains tested was 33.6% for speA, 99.3% for speB, 28.9% for speC, and 100% for slo. Strains of non-group A streptococci, recognized toxigenic bacterial pathogens, and pneumolysin-producing Streptococcus pneumoniae strains were negative for all targeted gene sequences. Detection limits in the PCR were found to be 100 pg of total nucleic acids for the speB and speC genes and 1 ng for the speA and slo genes. Isolates associated with scarlet fever, pharyngitis, and severe invasive infections showed statistically significant differences in the presence of speA, with scarlet fever strains having the highest association (81.3%), severe infections the next highest association (42.9%), and pharyngitis the lowest association (18.4%). Although no significant differences were observed in speC frequencies in isolated associated with the three disease categories, a genotype of speB slo was significantly higher in isolates associated with pharyngitis (54.1%) than in strains associated with scarlet fever (18.8%) or severe invasive disease (23.8%). Streptolysin O targets were present in all the isolates tested, and only a single strain (T-11-M-11) was devoid of targeted speB sequences, thereby demonstrating that neither speB nor slo is associated with any particular clinical presentation.

Journal Article Neonatal Listeriosis Due to Cross-Infection Confirmed by Isoenzyme Typing and DNA Fingerprinting Get access J. M. Farber, J. M. Farber Health and Welfare Canada, Ottawa Reprints or correspondence: Dr. J. M. Farber, Microbiology Research Division, Health Protection Branch, Banting Building, Bureau of Microbial Hazards, Health & Welfare Canada, Ottawa, Canada KIA OL2. Search for other works by this author on: Oxford Academic PubMed Google Scholar P. I. Peterkin, P. I. Peterkin Health and Welfare Canada, Ottawa Search for other works by this author on: Oxford Academic PubMed Google Scholar A. O. Carter, A. O. Carter Health and Welfare Canada, Ottawa Search for other works by this author on: Oxford Academic PubMed Google Scholar P. V. Varughese, P. V. Varughese Health and Welfare Canada, Ottawa Search for other works by this author on: Oxford Academic PubMed Google Scholar F. E. Ashton, F. E. Ashton Health and Welfare Canada, Ottawa Search for other works by this author on: Oxford Academic PubMed Google Scholar E. P. Ewan E. P. Ewan Health and Welfare Canada, Ottawa Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 163, Issue 4, April 1991, Pages 927–928, https://doi.org/10.1093/infdis/163.4.927 Published: 01 April 1991

A novel rat hepatocidal test, based on morphological changes in monolayer culture and the percentage of lactate dehydrogenase (LDH) released into the medium after exposure to culture filtrates of Listeria spp. was used to determine listerial toxicity and pathogenicity. Primary cultures of rat hepatocytes exposed to brain heart infusion (BHI) culture filtrates from ATCC strains of Listeria monocytogenes and L. ivanovii, released 91–92% and 95% of LDH after 3 h and 18.5 h, respectively. Cultured monolayers changed from normal hepatocytes into nonviable round forms. Brain heart infusion broth and BHI culture filtrates of other Listeria spp. were nontoxic to hepatocytes. The rat hepatocidal test is a quantitative and rapid system for studying listerial toxicity and pathogenicity.

Hybridomas derived from mice immunized with Neisseria meningitidis serogroup B serotype 2b (B,2b) outer membrane preparations produced monoclonal antibodies (MAbs) specific for major outer membrane proteins of classes 1, 2, and 5. The MAbs were examined by enzyme-linked immunosorbent assay against a selected panel of seven strains of N. meningitidis (B,2b) of different sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns, a serotype 2a, and a nontypable strain. The five MAbs selected were all bactericidal and of different immunoglobulin subclasses. None of the MAbs reacted with other bacterial strains in a dot-enzyme immunoassay. The corresponding antigenic determinant for each MAb was localized on a specific outer membrane protein by immunoblotting of sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of major outer membrane proteins. MAbs M5-11 and M5-30 bound to the class 2 protein and were serotype 2b specific. MAb M2-20 bound to the class 1 protein, and MAbs M5-16 and M5-19 bound to the class 5 protein. A mouse model of infection was established whereby a local infection progressed to lethal bacteremia over 3 days, and 50% of the animals were killed with an intraperitoneal injection of 10 meningococci plus 4% mucin and 1.6% hemoglobin. The ability of the MAbs to provide passive protection against experimental infection with N. meningitidis (B,2b) was examined. Both serotype-specific MAbs M5-11 and M5-30 were highly protective even though they were of different immunoglobulin subclasses. The class 5-specific MAb offered no protection, while the class 1-specific MAb gave limited protection. It may therefore be possible to provide protection against serotype 2b infection by using as vaccine the class 2 serotype-specific surface-exposed outer membrane protein epitopes defined by MAb M5-11 or M5-30.

The serotypes of meningococci isolated from 76 sporadic cases of meningococcal disease in South Australia during the years 1971 through 1980 were determined. Thirty-four (56%) of the 61 group B strains were nontypable; the remainder were of five serotypes namely 8 (16%), 1 (13%), 2 (2a and 2b) (9%), 12 (3%), and 15 (3%). Four of the five group B type 2 strains were serotype 2b. Serotype 2a accounted for four of seven group C strains and four of five group W135 strains. Overall serotypes 2 (2a and 2b) (17%), 8 (13%), and 1 (10%) occurred most frequently amongst the typable strains, whereas 40 (53%) of the 76 strains were nontypable. The results indicate that several serotypes and many nontypable strains were responsible for the sporadic disease occurring during a 10-year period in Australia.

The distribution of serotypes among strains of Neisseria meningitidis responsible for a marked increase of meningitis cases in the Hamilton area, Ontario, in 1978 and 1979 was determined. Twenty-six serogroup B and two serogroup W135 strains isolated from cerebrospinal fluid, blood, and skin of 28 patients were serotyped by agar gel double diffusion. Twenty-one (81%) of the group B strains were serotype 2b as judged by the formation of characteristic serotype precipitin bands with the specific anti-2996 (type 2b) serum. Fourteen of the serotype 2b strains also reacted with anti-77252 serum, which suggested that one strain or several closely related strains were mainly responsible for the increase in meningitis during the 2-year period. Examination of the outer membrane complexes (OMC) of the strains by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) revealed that all 21 of the serotype 2b strains contained the class 2 protein (molecular weight 41500) which is known to be the site of the serotype 2b determinant. Further characterization of the serotype 2b, 77252 strains by enzyme-linked immunosorbent assays (ELISA) and SDS-PAGE suggested that the 77252 determinant was present in the class 1 proteins of these strains. The serotype 2b containing strains were isolated from 77.7 and 70% of males and females, respectively, from 81.8% of children less than 5 years of age, and from 75.0% of patients of all age groups. The study indicates the important role of serotype 2b meningococci in causing the increased incidence of meningitis and further substantiates the important association of the serotype 2b determinant with group B serotype 2 meningococcal disease in Canada.