Association between mortality of Escherichia coli meningitis in young infants and non-virulent clonal groups of strains.
To identify factors associated with Escherichia coli meningitis (ECM) mortality in infants aged <3 months, the clinical, biological and bacterial characteristics of isolates from 99 cases of ECM were compared, including the phylogenetic group, multilocus sequence type, O serogroup and sequence O type (a combination of sequence type complex (STc) and O serogroup) and virulence genotype. All 99 isolates were susceptible to the initial antimicrobial treatment. The mortality rate (14%) was not influenced by term or post-natal age. Hypotension or seizures were the sole clinical predictive factors for fatal outcome (p <0.01), and abnormal initial trans-fontanellar ultrasound was associated with death (p 0.03). Seventy-seven isolates belonged to the common sequence O types (STc29(O1), STc29(O18), STc29(O45), STc301(O7), STc304(O16), STc697(O83), STc700(O1)) causing neonatal meningitis. None of the phylogenetic groups and none of the virulence determinants were distributed differently between survivors and non-survivors, except that the aerobactin gene (iucC) was less frequent in lethal isolates (94% vs. 71%, p 0.02). Isolates belonging to rare sequence O types were more likely to be lethal (OR 4.3, p 0.01), although they induced a lower level of bacteraemia than common sequence O types such as STc29(O18) and STc29(O45) in a neonatal rat model. These results suggest that unidentified human genetic risk-factors may be more important than strain virulence in predicting ECM mortality.
Laboratoire d'études de génétique bactérienne dans les infections de l'enfant (EA3105), Université Denis Diderot-Paris 7, AP-HP, Hôpital Robert Debré, Service de Microbiologie, Paris, France.
V
V
Houdouin
S
S
Bonacorsi
P
P
Bidet
J
J
Blanco
F
F
De La Rocque
R
R
Cohen
Y
Y
Aujard
E
E
Bingen
D000818:Animals; D016470:Bacteremia / Q000401:mortality; D015373:Bacterial Typing Techniques; D004926:Escherichia coli / Q000145:classification / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000032:analysis; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D020814:Meningitis, Escherichia coli / Q000401:mortality*; D019081:O Antigens / Q000032:analysis; D010802:Phylogeny; D051381:Rats; D017207:Rats, Sprague-Dawley; D014774:Virulence
D029968:Escherichia coli Proteins; D019081:O Antigens