agar and Meningococcal-Infections

Neisseria meningitidis is an encapsulated Gram-negative bacterium responsible for significant morbidity and mortality worldwide. Meningococci are opportunistic pathogens, carried in the nasopharynx of approximately 10% of asymptomatic adults. Occasionally they enter the bloodstream to cause septicaemia and meningitis. Meningococci are classified into serogroups on the basis of polysaccharide capsule diversity, and serogroup A strains have caused major epidemics mainly in the developing world. Here we describe a two-dimensional gel electrophoresis protein map of the serogroup A strain Z4970, a clinical isolate classified as ancestral to several pandemic waves. To our knowledge this is the first systematically annotated proteomic map for N. meningitidis. Total protein samples from bacteria grown on GC-agar were electrophoretically separated and protein species were identified by matrix-assisted laser desorption/ionization time of flight spectrometry. We identified the products of 273 genes, covering several functional classes, including 94 proteins so far considered as hypothetical. We also describe several protein species encoded by genes reported by DNA microarray studies as being regulated in physiological conditions which are relevant to natural meningococcal pathogenicity. Since menA differs from other serogroups by having a fairly stable clonal population structure (i.e. with a low degree of variability), we envisaged comparative mapping as a useful tool for microevolution studies, in conjunction with established genotyping methods. As a proof of principle, we performed a comparative analysis on the B subunit of the meningococcal transferrin receptor, a vaccine candidate encoded by the tbpB gene, and a known marker of population diversity in meningococci. The results show that TbpB spot pattern variation observed in the maps of nine clinical isolates from diverse epidemic spreads, fits previous analyses based on allelic variations of the tbpB gene.

Topics: Agar; Alleles; Bacterial Proteins; Densitometry; Electrophoresis, Gel, Two-Dimensional; Genes, Bacterial; Genetic Variation; Humans; Hydrogen-Ion Concentration; Meningococcal Infections; Neisseria meningitidis; Oligonucleotide Array Sequence Analysis; Proteome; Proteomics; Species Specificity; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Statistics as Topic

The E test (AB Biodisk, Solna, Sweden), a new approach developed to test antimicrobial susceptibility, was compared with the agar dilution method for seven-drug antibiogram analysis of Neisseria meningitidis isolates. The overall E-test quantitative accuracy (+/- 1 log2 dilution) was 93% compared with that of agar dilution testing. The E test was then used to perform the susceptibility tests on a 10-year sample of 102 N. meningitidis isolates, including 5 from a recent epidemic outbreak in the University of Iowa (Iowa City) community. The E test proved to be an efficient methodology for identifying common source clusters of meningococcal disease having resistance to rifampin or sulfonamides. Moreover, the data demonstrated a recent increase in penicillin MICs (MIC for 90% of strains, 0.094 microgram/ml) and an escalation of high-level resistance to trimethoprimsulfamethoxazole (33%) and rifampin (14%). The E test should be considered a simple and accurate susceptibility method for the emerging need to test meningococci and other pathogenic neisserias. Chocolate Mueller-Hinton agar was observed to provide the best support of growth and E-test MIC results that correlated well with results of the reference agar dilution method previously used for neisserias.

Topics: Agar; Disease Outbreaks; Drug Resistance, Microbial; Epidemiologic Methods; Evaluation Studies as Topic; Humans; Iowa; Meningococcal Infections; Microbial Sensitivity Tests; Neisseria meningitidis

Topics: Agar; Carrier State; Caseins; Culture Media; Evaluation Studies as Topic; Humans; Meningococcal Infections; Neisseria meningitidis; Yeasts

Topics: Agar; Animals; Anti-Bacterial Agents; Culture Media; Drug Resistance, Microbial; Drug Synergism; Enterobacteriaceae; Enterobacteriaceae Infections; Escherichia coli Infections; Folic Acid Antagonists; Haemophilus Infections; Meningococcal Infections; Mice; Microbial Sensitivity Tests; Pneumococcal Infections; Pyrimidines; Streptococcal Infections; Sulfamethoxazole

Topics: Agar; Carrier State; Child, Preschool; Colistin; Culture Media; Diagnosis, Differential; Humans; Infant; Lincomycin; Meningococcal Infections; Methods; Neisseria meningitidis; Nystatin; Pharynx