J B Robbins

EPIDEMIOLOGY OF ESCHERICHIA COLI K1 IN HEALTHY AND DISEASED NEWBORNS

Although at least 100 different Escherichia coli capsular antigens have been recognised, strains possessing the K1 antigen are responsible for 77% of neonatal E. coli meningitis cases. K1 strains were found in 20-40% of rectal swab cultures from healthy infants, children, and adult women. Vertical transmission from mother to infant was the most common means of aquiring K1 organisms in term infants. Premature babies in a nursery with little maternal contact aquired K1 strains later then did term infants, and this aquisition may have been related to carriage by nursery staff. Capsular content and fermentation reactions of cerebrospinal-fluid K1 organisms were comparable to those found in rectal strains from healthy individuals. E. coli K1 with identical O and H antigens were found in maternal and infantile cultures of babies with E. coli meningitis. It seems very likely that host immune mechanisms play a significant role in the pathogenesis of neonatal E. coli K1 meningitis.

RELATION BETWEEN ESCHERICHIA COLI K1 CAPSULAR POLYSACCHARIDE ANTIGEN AND CLINICAL OUTCOME IN NEONATAL MENINGITIS

Abstract The clinical outcome in fifty-seven infants with Escherichia coli meningitis was analysed with respect to the presence or absence of K1 capsular polysaccharide antigen. Mortality and morbidity in E. coli K1 meningitis were significantly greater than in meningitis caused by E. coli non-K1 strains. The amount of K1 antigen and length of time K1 antigen was present in serum and cerebrospinal fluid, as measured by countercurrent immuno-electrophoresis, were directly related to clinical outcome. E. coli K1 strains were more virulent in mice than non-K1 strains, and the lethal dose of K1 strains from infants who died was significantly lower than those values from infants who survived E. coli K1 meningitis.

Clinical, bacteriological, and immunological characterisation of ampicillin-resistant Haemophilus influenzae type B.

Abstract Ampicillin-resistant Haemophilus influenzae type b (H.I.T.B.) was isolated from the cerebrospinal fluid of 1 of 3 children with H.I.T.B. meningitis, attending the same day-care centre. 81 children and 13 adults, from the same area as the 3 cases, were examined for nasopharyngeal carriage of H.I.T.B. Six ampicillin-resistant and four ampicillin-sensitive strains were recovered from the children. When 46 of these children were re-examined and had blood drawn one month later, 11 carriers of H.I.T.B. were found. High levels of H.I.T.B. antibody were associated with persistent carriage of either the ampicillin resistant or sensitive strains. All isolates from children at the day-care centre were ampicillin resistant during both surveys.

Human cell-surface structures related to Haemophilus influenzae type b disease.

Abstract Twenty-six patients with Hœmophilus influenzœ type b disease were investigated by erythrocyte and lymphocyte phenotypes and by lymphocytotoxicity with antibodies to H. influenzœ type b. These studies suggest a relationship between host cell-surface structures and susceptibility to H. influenzœ type b disease in non-immune individuals.