Contribution of capsular and clonal types and beta-lactam resistance to the severity of experimental pneumococcal meningitis.
We used a rabbit model to assess the effects of capsular serotype, genetic background and beta-lactam resistance on the course and severity of experimental meningitis. Meningitis was induced by five pneumococcal strains belonging to five different clones with known invasive potential: two serotype 3 strains (ST260(3) and Netherlands(3)-31 clones) and three serotype 23F strains with different beta-lactam susceptibility patterns (Spain(23F)-1 clone, Tennessee(23F)-4 clone and a double locus variant of the Tennessee(23F)-4 clone). Major differences in secondary bacteremia and mortality rates were observed between serotypes 3 and 23F, as were divergences in the CSF lactate, protein and lipoteichoic-teichoic acid concentrations. Minor differences in the CSF-induced inflammatory response were found among strains belonging to the same serotype. Our results suggest that capsular serotype might be the main factor determining the course and severity of pneumococcal meningitis and genetic background contributes to a lesser extent. The acquisition of beta-lactam resistance does not reduce the virulence of the invasive clones. Since five strains belonging to two serotypes were studied, our findings have to be confirmed with other pneumococcal serotypes.
Ribes
Sandra
S
Laboratory of Experimental Infection, Infectious Diseases Department, Hospital Universitari de Bellvitge - IDIBELL - University of Barcelona, Feixa Llarga s/n, 08907 Hospitalet de Llobregat, Spain. sribes@ub.edu
Taberner
Ferran
F
Cabellos
Carmen
C
Tubau
Fe
F
Ardanuy
Carmen
C
Gerber
Joachim
J
Liñares
Josefina
J
Nau
Roland
R
Gudiol
Francesc
F
D000328:Adult; D000818:Animals; D016470:Bacteremia / Q000382:microbiology; D016667:Bacterial Capsules / Q000276:immunology; D001769:Blood / Q000382:microbiology; D002555:Cerebrospinal Fluid / Q000737:chemistry / Q000382:microbiology; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D019344:Lactic Acid / Q000134:cerebrospinal fluid; D008070:Lipopolysaccharides / Q000134:cerebrospinal fluid; D008586:Meningitis, Pneumococcal / Q000382:microbiology* / Q000473:pathology; D008826:Microbial Sensitivity Tests; D011008:Pneumococcal Infections / Q000382:microbiology; D011506:Proteins / Q000032:analysis; D011817:Rabbits; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D013682:Teichoic Acids / Q000134:cerebrospinal fluid; D014774:Virulence; D018440:beta-Lactam Resistance
D004269:DNA, Bacterial; D008070:Lipopolysaccharides; D011506:Proteins; D013682:Teichoic Acids; D019344:Lactic Acid; C009900:lipoteichoic acid