of Dise in Childhood 1991 ; 66 : 437 - 4 4 Neonatal Haemophilus influenzae infections

Nine cases of neonatal Haemophilus influenzae septicaemia were recorded in Finland during 1985-9; incidence was 2-8/100 000 live births, and 1-6% of all cases of neonatal septicaemia. The onset of the disease was early in all cases, ranging from 0-6 hours after delivery. Seven of the infants were preterm and three died (overall mortality 33%). H influenzae was isolated from blood in seven of the cases, and in two neonates with clinical signs of septicaemia it was found on several surface sites and the placenta. One of the eight strains of H influenzae was capsular type b and biotype I, the rest being nontypable-a distribution similar to those previously reported. Four of the uncapsulated strains were of biotype m, and three were of biotype II. None of the strains ofH influenzae was of biotype IV, which has been reported to be characteristic of neonatal and genital isolates of H influenzae. All nine mothers had some sign of infection at the time of or shortly after delivery. H influenzae was isolated from five mothers: from the blood (n=l) or from the placenta or cervix (n=4). The use of intrauterine devices may be a possible risk factor for neonatalH influenzae infections; two of the mothers had such devices in place during their pregnancies. National Public Health Institute, Mannerheimintie 166, SF400300 Helsinii, Finland A K Takala E Pekkanen J Eskola Correspondence to: Dr Takala. Accepted 18 September 1990 Neonatal Haemaphilus influenzae infections were once thought to be rare, but during the past decades an apparent increase of such infections has been reported.' 2 H influenzae infections have been found mainly among preterm, low birthweight infants,2' and are characterised by the early onset of symptoms and the fulminant course of the disease.2 6 It has been suggested that these infections may have started during pregnancy and are the cause of the premature birth.7 The mortality associated with neonatal H influenzae septicaemia is high, up to 86% having been reported.3 6 Most (80-90%) of the strains ofH influenzae that cause neonatal septicaemia are nonencapsulated,8 whereas 95% of strains that cause invasive disease among older children are capsular type b.9 The neonatal strains and the strains that colonise the female genital tract have been reported to be predominantly biotype IV, and seldom biotype II or III,8 10 whereas most of strains with the type b capsule are of biotypes I or II."l-"3 A nationwide intensified surveillance of invasive infections in children (including neonates) was started in Finland in 198514 as a part of a trial of the efficacy of a vaccine against H influenzae capsular type b.'5 We report the results of a five year prospective follow up of neonatal H influenzae infections in Finland and describe the clinical and bacteriological features of nine cases of neonatal H influenzae infection. Patients and methods In the nationwide surveillance all bacterial insolates from blood, cerebrospinal fluid, or other sterile body sites of children (0 to 15 years of age) with invasive disease were sent to the National Public Health Institute from the 25 microbiological laboratories in Finland. In addition, if a neonate (defined as an infant less than 28 days of age) was thought clinically to have septicaemia and the same bacterial species was isolated from many surface sites (for example, ear, umbilicus, or throat) and the placenta, this strain was included in the collection. The identification of strains was confirmed at the National Public Health Institute and samples were stored at -700C. The laboratory records from the years 1985-9 in each of the laboratories were also examined retrospectively to find possible omissions from the collection. Detailed data about the patients and their mothers were collected from the hospital records. The capsular types (a-f) of the strains of H influenzae were ascertained by a coagglutination technique."1 Strains were designated to biotypes I-VIII on the basis of their urease and ornithine decarboxylase activity and the production of indole.'6 Production of ,3-lactamase was tested by the clover leaf method'7 or the acidometric assay, or both.'8