Therapy of Haemophilus influenzae meningitis reconsidered

Chloramphenicol kills Haemophilus influenzae more rapidly than does ampicillin or cefamandole

The bactericidal effects of chloramphenicol and three beta-lactams (ampicillin, cefamandole, and penicillin G) were measured for 27 strains of Haemophilus influenzae type b isolated from the blood or cerebrospinal fluid of infected infants. Of the ampicillin-susceptible strains, 75% were killed by less than 2.0 micrograms of each antibiotic per ml; however, the concentration of the beta-lactam agents required for bactericidal activity was higher than that required for inhibitory activity. Chloramphenicol was the only agent which had no marked discrepancy between inhibitory and bactericidal concentrations regardless of beta-lactamase production. Importantly, chloramphenicol was more rapidly bactericidal than either ampicillin or cefamandole. The bactericidal requirement of ampicillin was increased by the presence of chloramphenicol for about one-third of the isolates examined. Neither the inhibitory nor the bactericidal activity of chloramphenicol was influenced by ampicillin. Synergy occurred for only two beta-lactamase-positive isolates. The more rapid bactericidal action of chloramphenicol persisted even in the presence of ampicillin. The rapid bactericidal action of chloramphenicol with or without ampicillin supports the use of chloramphenicol alone or with ampicillin for H. influenzae infections.

Outer membrane protein subtypes and investigation of recurrent Haemophilus influenzae type b disease

Ten previously healthy patients, ages 3 to 26 months, developed recurrent episodes of deep-tissue Haemophilus influenzae type b infections from 4 to 191 days (median = 28 days) after the last day of antibiotic therapy given for the first episode. None of the patients had a persistent focus of infection and eight were considered to have had adequate therapy for the initial episode. Bacteremia, without evidence of relapse at the site of the original infection, was documented in eight of the ten recurrent episodes. The ampicillin susceptibilities of the HITB isolates changed between episodes in two of the patients. Blood or CSF isolates from both episodes in seven patients were examined for biotypes and outer membrane protein subtypes. Concordance of both biotype and OMP subtype was present for all seven paired isolates, including the two pairs in which the HITB ampicillin sensitivities had changed. These data imply that some patients become reinfected with their original HITB isolates and that OMP and capsular antigens do not always elicit protective immunity, even after natural infection.

Oral chloramphenicol in the treatment of Haemophilus influenzae meningitis

We conducted a prospective, randomized evaluation of oral chloramphenicol administration for completion of therapy of Haemophilus influenza type b meningitis in 44 children: 21 received drug by this route after the second day of therapy, the remainder continued to receive the drug intravenously. Resolution of clinical manifestations and cerebrospinal fluid indicators of meningitis was equivalent with both routes in 43 patients. One infant failed to achieve efficacious serum concentrations by either route of administration. Paired analysis of the area under the serum concentration versus time curve in 13 patients after oral and intravenous administration indicated equivalent bioavailability. Neutropenia was the only observed drug-related toxicity and correlated with the highest observed serum concentration. We conclude that: (1) chloramphenicol can be used by the oral route to complete treatment of H. influenzae type b meningitis; (2) a dose of 75 mg/kg/day is effective and less likely than higher doses to cause neutropenia; and (3) the measurement of serum chloramphenicol concentrations is important, regardless of route of administration.

Hemophilus influenzae type B buccal cellulitis

During a 10-year period there were seventy-two cases of buccal cellulitis caused by Hemophilus influenzae type b (HIb). Patients ranged in age from 3 months to 3 years; 72% were less than 2 year of age. Most children had a poorly demarcated, violaceous discoloration of one cheek. Sixty-eight percent of patients had an associated otitis media, and HIb was isolated from middle ear aspirates of twenty-two of twenty-three children. Bacteremia was present in 86% of patients, and five (7.6%) had associated meningitis. Ampicillin, chloramphenicol, cephamandole, or a combination of ampicillin and chloramphenicol, all proved effective for therapy of this condition. The duration of fever was more prolonged after cephamandole or ampicillin than after a combination of ampicillin and chloramphenicol or chloramphenicol alone. Recommendations for diagnosis and treatment are made.

Haemophilus influenzae meningitis. A comparison between chloramphenicol and ampicillin therapy with special reference to impaired hearing

131 patients suffering from meningitis due to Haemophilus influenzae or parainfluenzae were re-examined after 1-15 years, using hospital records, questionnaires, and audiological examination, especially to compare chloramphenicol and ampicillin therapy. Mortality was 3.8%. Subdural effusions occurred in 14.5% of cases uni- or bilaterally. There was deafness in 2.3%, and moderate hearing loss in 8.4%. Convulsions appeared later in 6.9%. The final outcome was good in 60%. The most important factors in prognosis seemed to be the severity of the symptoms and the condition of the patient on admission to hospital. No clear difference was seen between the results of chloramphenicol and ampicillin therapy, but total loss of vestibular function was found in 3 cases in the ampicillin group, and in none in the chloramphenicol group. In mortality and deafness, the differences in outcome were similar, although not statistically significant. As these observations show, the therapy used in Haemophilus influenzae meningitis needs re-evaluation.

Tone audiometry control of children treated for meningitis with large intravenous doses of ampicillin

Thirty-seven children treated for bacterial meningitis with ampicillin in high doses were followed up with audiometric control. Defects were recorded in 6 cases. Two of these were ascribed to chronic otosalpingitis. In 4 patients with sensorineural hearing loss, 3 were unilateral, and in only one case was the damage bilateral. Even here there was a previous history of hearing loss. A suggested ototoxicity of ampicillin could not be confirmed.

Hearing loss as a sequel to chloramphenicol and ampicillin treatment of Haemophilus influenzae meningitis

20 patients with Haemophilus influenzae meningitis who had been treated with chloramphenicol over the period 1959-1970 and 23 patients who had been treated with ampicillin over the period 1968-1974 were re-examined by hearing tests in 1975. In all the cases the two agents had been given initially by the parenteral route, chloramphenicol in doses varying between 50 and 150 (averaging 101) mg/kg/day and ampicillin in doses varying between 125 and 350 (averaging 229) mg/kg/day. Five of the 20 patients in the chloramphenicol group were found to be deaf on one ear, whereas 1 of the 23 patients in the ampicillin group was completely deaf. A further 3 in the chloramphenicol group and 1 in the ampicillin group had slight sensorineural hearing loss on one ear. Only in 2 of the 6 deaf patients was the loss discovered during the time of hospital care. The present study has not provided any evidence supporting the recently reported observation (Gamstorp and Klockhoff, 1974) that the frequency of hearing loss might be higher after ampicillin than after chloramphenicol treatment for H. influenzae meningitis.

Concentrations of bacteria in cerebrospinal fluid of patients with bacterial meningitis

Concentrations of bacteria in cerebrospinal fluid ranged from 4.5 X 10(3) to 3 X 10(8) colony-forming units/ml in 27 patients with bacterial meningitis before antibiotic therapy and from 4 X 10(1) to 1.4 X 10(6) CFU/ml in four patients after one to two days of antibiotic therapy. All patients with persistent positive cultures had pretreatment concentrations of 10(7) CFU/ml or greater. A significant association was observed between cerebrospinal fluid lactic acid dehydrogenase activity and concentrations of bacteria (p less than 0.01). Large inocula of Hemophilus influenzae type b (10(7)) increased the minimal inhibitory concentration for penicillin and ampicillin but not for chloramphenicol. The minimal inhibitory concentration of each of the three antibiotics increased when group B streptococci were assayed. These data indicate that persistence of a positive culture may be related to large initial concentrations of bacteria. The relative "resistance" in vitro of large inocula possibly contributes to this persistence. These observations are also consistent with the hypothesis that lactic acid dehydrogenase activity in cerebrospinal fluid is derived from bacteria.

Prospective evaluation of treatment of Hemophilus influenzae meningitis

Fifty children with Hemophilus influenzae meningitis have been enrolled in a prospective study. Patients were randomly assigned chloramphenicol or ampicillin treatment; there were no significant differences between groups in other respects. Countercurrent immunoelectrophoresis proved to be a valuable tool for rapid diagnosis of the causative agent even in pretreated patients. Increasing quantities of capsular polyribosephosphate antigen detected in the initial cerebrospinal fluid correlated significantly (r=0.62419; p less than 0.01) with early and late sequelae of meningitis. None of the patients died. Severe and persistent neurologic or intellectual deficits were noted in four (8%) of the children, and an additional 14 (28%) had IQ scores between 70 and 90. The presence of bactericidal antibody in serum was not protective. Anti-PRP antibody generally was not present in acute serum specimens and irrespective of the quantity of antigenic stimulus provided by the disease was nondetectable in 21 of 24 children less than 17 months of age following recovery.

Persistent pleocytosis in bacterial meningitis

Persistent pleocytosis of greater than 60 white blood cells/mm3 was commonly seen in children adequately treated for bacterial meningitis. It occurred in 13 of 21 (62%) children with Hemophilus influenzae meningitis and in 2 of 9 (22%) with pneumococcal meningitis. Pleocytosis alone cannot be used as an indication of prolonging therapy; significance of persistent pleocytosis is not known.

Hemophilus influenzae type B susceptibility to 17 antibiotics

One hundred and one strains of Hemophilus influenzae type b isolated at the Children's Hospital Medical Center from blood or CSF and 18 strains known to be resistant to ampicillin of which 17 were supplied to us by others were tested for their sensitivity to 17 antibiotics. Two groups were defined according to their sensitivity to ampicillin. When 10-3 bacteria were applied, 18 strains isolated from patients with ampicillin treatment failures had a median minimum inhibitory concentrations of 3.1 mug/ml. At 10-6 bacteria the median MIC for the resistant strains increased 512-fold, whereas the sensitive strains increased two-fold. The most active antibiotics against sensitive and resistant strains were rifampin, chloramphenicol, gentamicin, rosamycin, and erythromycin with MICs ranging from 0.2-0.8 mug/ml at 10-3 bacteria and from 0.2-1.6 mug/ml at 10-6.

Ampicillin-resistant Haemophilus influenzae type B possessing a TEM-type beta-lactamase but little permeability barrier to ampicillin

Ampicillin-resistant Haemophilus influenzae type B have been reported only during the past year. Five clinical isolates from the U.S. and Germany all had the TEM-type beta-lactamase which is known to be transferred widely among other gram-negative bacilli. Unlike those bacilli, however, the H. influenzae cell had very little barrier to entry of penicillins. This greater permeability of the H. influenzae cell to penicillins appeared to reduce the protective effect of its beta-lactamase, in that acquisition of the TEM-type beta-lactamase increased levels of resistance to penicillins much less for individual cells of H. influenzae than for those of Escherichia coli. Large inocula of either species appeared highly resistant. The unusually low level of resistance of individual cells of H. influenzae containing the TEM-type beta-lactamase may have delayed their emergence or recognition, and has unresolved clinical implications.

Some important pitfalls in the diagnosis and treatment of bacterial meningitis in children

Some of the common errors and problems of the physician who cares for the child with bacterial meningitis are: 1) misdiagnosis; 2) inappropriate handling of cerebrospinal fluid; 3) inadequate assessment of therapeutic responses; 4) inappropriate drug therapy; 5) improper treatment of seizures; 6) inadequate care of increased intracranial pressure; 7) inappropriate evaluation of persistent fever; 8) inappropriate fluid therapy; 9) inadequate investigation of persistent neurologic deficit; 10) overvigorous treatment of subdural effusion; 11) inadequate assessment of neurologic or psychologic impairment; and 12) inadequate consideration of possible underlying defects.

Haemophilus influenzae meningitis in adults

Haemophilus influenzae meningitis though common in childhood is rarely seen in the adult. During the past four years eight cases of H. influenzae meningitis have been seen in St. Thomas's Hospital and four of these were in patients over 20 years old. There was a possible predisposing condition in two patients. In each case there was difficulty in identification of the organism in the Gram-stained film of the cerebrospinal fluid deposit.