Low dosage and long treatment duration of beta-lactam: risk factors for carriage of penicillin-resistant Streptococcus pneumoniae

JAMA. 1998 Feb 4;279(5):365-70. doi: 10.1001/jama.279.5.365.


Context: The spread of drug-resistant Streptococcus pneumoniae in the community is a public health problem in developed and developing nations, but whether antibiotic use is responsible for the increase in drug resistance is not known.

Objective: To analyze the relationship between penicillin-resistant S pneumoniae (PRSp) pharyngeal carriage and characteristics of beta-lactam use.

Design: Observational study of children attending 20 randomly sampled schools.

Setting: The Loiret, in the center of France.

Participants: A total of 941 children, 3 to 6 years old.

Main outcome measure(s): Pharyngeal carriage of S pneumoniae, antibiotic use, and medical events during the preceding 30 days. Pneumococcal penicillin G sodium minimal inhibitory concentrations and serotyping were performed.

Results: Medical illnesses and the use of antibiotics were not associated with PRSp carriage. However, oral beta-lactam use was associated with an increased risk of PRSp carriage (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.1-8.3; P=.03). Children treated by low daily doses of an oral beta-lactam (defined as lower than clinical recommendations) had an increased risk of PRSp carriage, as compared with children who did not (OR, 5.9; 95% CI, 2.1-16.7; P=.002). A treatment of long duration (>5 days) with a beta-lactam was associated with an increased risk of PRSp carriage (OR, 3.5; 95% CI, 1.3-9.8; P=.02).

Conclusions: Our results suggest that a low daily dose and a long duration of treatment with an oral beta-lactam contribute to the selective pressure in promoting pharyngeal carriage of PRSp.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / administration & dosage*
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Child
  • Child, Preschool
  • Data Collection
  • Drug Administration Schedule
  • France / epidemiology
  • Humans
  • Logistic Models
  • Microbial Sensitivity Tests
  • Multivariate Analysis
  • Penicillin Resistance*
  • Pharynx / microbiology
  • Pneumococcal Infections / drug therapy*
  • Pneumococcal Infections / epidemiology*
  • Risk Factors
  • Schools
  • Serotyping
  • Streptococcus pneumoniae / classification
  • Streptococcus pneumoniae / drug effects*
  • Streptococcus pneumoniae / isolation & purification
  • beta-Lactams


  • Anti-Bacterial Agents
  • beta-Lactams