a SLACK Incorporated newspaper
May 1999
BOSTON - A recent study found that reduced antibiotic susceptibility to penicillin does not alter the clinical presentation of pneumococcal bacteremia in children. Doctors are encouraged to continue using conventional therapies for pneumococcal infections, which consist of b-lactam treatments, without the inclusion of additional antibiotics such as vancomycin.
The retrospective study examined the increasing problem of drug-resistant pneumococcus in 809 cases over 11 years. Previous studies have shown that 7% of invasive pneumococcal isolates studied were highly resistant to penicillin and 4% were extremely resistant to third-generation cephalosporins, with the problem being more severe in children. This study is the first to include analysis of morbidity, mortality, penicillin non-susceptibility and ceftriaxone non-susceptibility solely in children.
Out of the 744 cases including pneumococcal isolates, 688 patients were susceptible to penicillin whereas 56 patients were not. Both groups were similar when tested for initial respiratory rate, temperature and white blood cell count. It was also noted that patients with non-susceptible isolates were not more likely to be admitted at the first visit.
Only those treated with antibiotics at the first visit were included in the follow-up results. Again, there were no significant differences between the two groups in the categories previously mentioned. There was also no difference in the amount of positive repeat blood cultures. There were 38 new focal infections among the susceptible group and five among the non-susceptible group. Three deaths resulted in the susceptible group, one due to meningitis, and one death in the non-susceptible group, also due to meningitis.
The 688 patients who had penicillin-susceptible organisms were compared to the nine patients who had penicillin-resistant organisms. There were no differences between the two groups except in length of hospital stay. Two of the nine non-susceptible patients developed new focal infections, both of which were meningitis, one resulted in death.
At initial presentation, there were no significant differences between the 716 patients harboring ceftriaxone susceptible isolates and the 14 non-susceptible patients, with the exception of heart rate. Non-susceptible patients were more likely to have a chronic illness, which was unrelated to their higher admittance rate at the initial visit.
According to the study, "because penicillin-susceptible strains were also ceftriaxone-susceptible, the 38 new focal infections reported among the penicillin-susceptible group" were included in the 39 new focal infections in the ceftriaxone-susceptible group. The one case added was of nonfatal pneumonia. Two new focal infections were found among the ceftriaxone-non-susceptible group, one of which resulted in death due to meningitis.
Researchers felt that study results for ceftriaxone resistance were vague however and state that "ceftriaxone non-susceptibility may have more significant clinical implications, and more studies will be needed to evaluate the exact nature of these implications."
The study looked at all positive blood cultures taken at Children's Hospital, Boston, between Jan. 1, 1987 and Dec. 31, 1997. Blood cultures were only considered if they were taken as part of initial outpatient evaluation. Patients with insufficient data were excluded from the clinical section of the study but were included in the statistics of antibiotic susceptibility occurrences.
Aspects of the initial blood culture noted included temperature, respiratory rate and antibiotic therapy within the previous two days among other things. Antibiotic prescriptions for outpatient therapy were also recorded. New focal infections were determined by comparing discharge information with admittance diagnoses. "New infections were defined as meningitis, persistent bacteremia, pneumonia, septic arthritis, osteomyelitis, cellulitis and death. Pharyngitis and otitis media, even when newly diagnosed, were not considered new infections," the authors said.
For more information:
- Silverstein M. Bachur R. Harper MB. Clinical implications of penicillin and ceftriaxone resistance among children with pneumococcal bacteremia. Pediatr Infect Dis J.1999;18:35-41.
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