Haemophilus influenzae type b bacteremia in older children.

Haemophilus influenzae type b (HIB) is a well-recognized cause of serious infection in infants and toddlers. However, little information exists regarding HIB infections in older children. This report describes serious HIB infections in 23 children (eight immunocompromised; 15 immunocompetent) older than 59 months of age. Data were collected over an 11-year period. The mean age of the children was 7.6 years (range, 5-15 years), and 14 were male. While three of the eight immunocompromised children had HIB pneumonia, none of the immunocompetent group had this diagnosis. Eleven of the 15 immunocompetent children had epiglottitis or meningitis. HIB bacteremia without focal infection occurred in four children, two immunocompromised and two immunocompetent. This study supports the recommendation of empiric HIB antibiotic therapy for children up to 12 years of age who have serious infections. Antibiotics effective against HIB should be included in the presumptive antibiotic therapy of seriously ill immunocompromised children, regardless of age.     

Endophthalmitis associated with Haemophilus influenzae type b bacteremia and meningitis.

The unusual occurrence of endophthalmitis associated with Haemophilus influenzae type b bacteremia and meningitis was confirmed in three young children during a five-year period. In contrast to bacterial endophthalmitis attributed to other microorganisms, these three infections resolved completely within a few days with conventional antimicrobial therapy. Endophthalmitis is but one of the apparently increasing number of unsuual complications that may be observed as a result of H influenzae type b bacteremia.     

Outcome of children with occult bacteremia caused by Haemophilus influenzae type b.

For better definition of the clinical course and outcome of children with occult bacteremia caused by Haemophilus influenzae type b (Hib), we reviewed the medical records of children who were initially managed as outpatients and subsequently found to be bacteremic. At Yale-New Haven Hospital (1971 to 1987) and the Children's Hospital of Philadelphia (1982 to 1987), 69 previously healthy children were identified with occult Hib bacteremia. Their median age was 14 months (range, 4 to 89 months). Thirty-six (52%) of the 69 were either febrile and/or had a focus of serious infection at follow-up (meningitis (17), pneumonia (5), epiglottitis (3), cellulitis (5), and septic arthritis (3)). Although the remaining 33 children (48%) were afebrile and appeared well on reevaluation, 3 of these 33 were still bacteremic and another 5 subsequently developed focal Hib infections. These 8 children were significantly younger (median age, 8.5 months) than the 25 children who remained well (median age, 16 months; P = 0.03). Of the 28 children who had initially been treated with antimicrobials to which their organism was known to be susceptible, 12 (43%) were improved at reevaluation and remained well; 7 (23%) of the 31 patients who had not received such antimicrobials improved and remained well (P = 0.17). Children initially managed as outpatients and later found to have had Hib bacteremia are at risk of subsequently developing a serious focal infection.     

Haemophilus influenzae type b pneumonia.

Thirteen patients with Haemophilus influenzae type b pneumonia are reported to emphasise the clinical, radiographic, and therapeutic aspects of this illness. All but one patient was under 2 1/2 years of age. The presenting complaint was a variable duration of upper respiratory infection and fever in most cases. One-third of patients had radiographic evidence of pleural involvement; one-third showed a patchy bronchopneumonia on roentgenogram; and the remainder had segmental or lobar infiltrates. Clinical response to antibiotic therapy was prompt in patients without pleural involvement.     

Haemophilus influenzae type b osteomyelitis.

Three children had osteomyelitis due to Haemophilus influenzae type b. They were seen with signs and symptoms indistinguishable from infection caused by other organisms. One child was initially misdiagnosed as having septic arthritis because of failure to appreciate that Hemophilus may also cause bone infection. In the second patient osteomyelitis and arthritis developed during ampicillin sodium therapy for treatment of Hemophilus meningitis. His initial infection was caused by an ampicillin-sensitive isolate but his orthopedic infection subsequently responded to therapy only after changing to a regimen of chloramphenicol. In the third patient, bone scintigraphy was helpful in diagnosis since serial roentgenograms were not diagnostic of osteomyelitis. The anticapsular antibody responses of these patients were measured by radioimmune assay. The levels found were low but comparable to age-matched control children with H influenzae type b meningitis.     

Unusual case of Haemophilus influenzae type b: Haemophilus influenzae type b meningitis cellulitis and subcutaneous abscess

An unusual case of beta-lactamase positive Haemophilus influenzae type b infection is reported. Clinical manifestations included meningitis, a left ankle subcutaneous abscess, and bilateral hand cellulitis. Discussion and review of literature are presented for the previously unreported association of this common childhood pathogen.     

New vaccines against Haemophilus influenzae type b

Recently, great progress has been made in the development of vaccines against Hib. Four polysaccharide-protein conjugate vaccines are actively being tested. Three of these (PRP-D, HbOC, and PRP-OMP) are currently licensed for use in children at 15-18 months of age. Clinical trials of these vaccines in infants are currently being conducted in the United States. If these show the vaccines to be efficacious, licensure for infants will follow. Although much work remains to be done, it seems likely that the effective prevention of serious Hib infections in infants, as well as in older children, is a goal that may be within our reach in the next several years.     

Haemophilus influenzae type b in respiratory secretions

Oral and respiratory secretions of 31 children who were healthy or had mild upper respiratory infection, and who had a positive throat culture for Haemophilus influenzae type b, were cultured to determine which secretions contain this organism and how long it can be recovered from fomites. Rhinorrhea was present in 11 of 31 (34%) children and nasal mucus was positive for H. influenzae type b in 10 (91%). In 5 of these children the concentration of H. influenzae type b in nasal mucus was 10(4) to 10(7) colony-forming units/ml3. H. influenzae type b in nasal mucus applied to fomites were recovered for 12 hours. Cultures of saliva and cough secretions compared with nasal mucus were less often positive (3 of 31, P less than 0.001; 3 of 25, P less than 0.001, respectively) and contained fewer H. influenzae type b (5 and 15 colony-forming units, respectively). H. influenzae type b was recovered from the hand of 2 of 27 (7%) children; both children had positive cultures of saliva. These data indicate that H. influenzae type b can be found in oral and respiratory secretions of pharyngeal carriers and can contaminate children's hands. Nasal mucus was the most consistently positive secretion and contained the largest number of bacteria. Careful management of nasal mucus secretions is warranted in settings where transmission could occur to susceptible children.     

Pneumococcal and Haemophilus influenzae type b antigen detection in children at risk for occult bacteremia

We prospectively evaluated pneumococcal and Haemophilus influenzae type b antigen detection in serum and urine of young (3 to 30 months of age) febrile (temperature greater than or equal to 39 degrees C) children at risk for occult bacteremia. Patients with septic shock, meningitis, or epiglottitis were excluded. Of 576 patients, 16 had pneumococcal bacteremia (final diagnoses: primary bacteremia, nine; otitis media, four; pneumonia, two; unknown, one), and five had H influenzae b bacteremia (final diagnoses: primary bacteremia, two; cellulitis, two; arthritis, one). Latex agglutination was positive in all five patients with H influenzae b bacteremia (positive in three of three urine specimens, three of four sera tested) but only one of 16 patients with pneumococcal bacteremia (positive in one of seven urine samples, zero of 13 sera tested). Both assays had specificities of greater than 95%. Nonspecific agglutination occurred in 7% of specimens tested. Enzyme immunoassay for pneumococcal antigen, although more sensitive than latex agglutination, failed to detect antigen in ten sera and three urine specimens from patients with pneumococcal bacteremia. Thus, neither latex agglutination nor enzyme immunoassay was sufficiently sensitive for detection of occult pneumococcal bacteremia. Latex agglutination for H influenzae b holds promise as a sensitive and specific test for rapid diagnosis of occult bacteremia due to H influenzae b.