Related Experiment Videos
Penicillin-resistant Streptococcus pneumoniae in acute otitis media: risk factors, susceptibility patterns and
S L Block1, C J Harrison, J A Hedrick
1Kentucky Pediatric Research, Bardstown 40004, USA.
Abstract:
From January, 1992, to January, 1994, penicillin-resistant (minimal inhibition concentration (MIC) > 0.06 microgram/ml) Streptococcus pneumoniae (PRSP) isolates accounted for 48 (17%) of 283 isolates from acute otitis media (AOM) or recurrent AOM in 246 ambulatory patients in rural Kentucky. By broth microdilution, relatively penicillin-resistant (MIC > 0.06 to 1.0 microgram/ml) and highly penicillin-resistant (MIC > or = 2.0 micrograms/ml) strains were detected in 25 (16%) and 23 (15%), respectively, of 157 pneumococcal middle ear isolates. Using 1994 National Committee for Clinical Laboratory Standards breakpoints for pneumococci (unavailable for oral cephalosporins except cefuroxime), highly PRSP strains were almost uniformly susceptible to clindamycin and vancomycin. In contrast highly PRSP strains were resistant to most oral antimicrobials customarily used for AOM with one-third of strains highly resistant (MIC > or = 2.0 micrograms/ml) to ceftriaxone. Serotypes 6B, 19F and 23F accounted for 95% of highly PRSP strains and serotype 9V for 48% of relatively PRSP strains. By multivariate analysis, otitis-prone condition (P = 0.0008) and number of antibiotic courses before day of culture (P < 0.0001) were independently predictive of PRSP. Highly PRSP isolates were more commonly isolated from patients recently treated within 3 days (30%) vs. those who completed therapy more than 3 days earlier (2%) (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Penicillin-resistant Streptococcus pneumoniae (PRSP) strains were common in acute otitis media cases in rural Kentucky. PRSP was linked to otitis-prone conditions and recent antibiotic use, with resistance to common AOM treatments.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Medicine
Background:
- Penicillin-resistant Streptococcus pneumoniae (PRSP) poses a growing challenge in treating acute otitis media (AOM).
- Understanding the prevalence and resistance patterns of PRSP in ambulatory settings is crucial for effective AOM management.
Purpose of the Study:
- To determine the prevalence of PRSP in pediatric AOM patients in rural Kentucky.
- To assess the antimicrobial susceptibility profiles of PRSP isolates.
- To identify risk factors associated with PRSP infections.
Main Methods:
- Retrospective analysis of Streptococcus pneumoniae isolates from patients with AOM or recurrent AOM.
- Broth microdilution method to determine penicillin minimal inhibition concentrations (MICs).
- Antimicrobial susceptibility testing against various oral and parenteral agents.
- Multivariate analysis to identify predictive factors for PRSP.
Main Results:
- PRSP accounted for 17% of 283 Streptococcus pneumoniae isolates from AOM cases.
- Highly PRSP strains (MIC ≥ 2.0 µg/mL) showed uniform susceptibility to clindamycin and vancomycin but resistance to many oral antibiotics, including ceftriaxone.
- Serotypes 6B, 19F, and 23F were predominant in highly PRSP strains.
- Otitis-prone condition and recent antibiotic exposure (within 3 days) were significant predictors of PRSP.
Conclusions:
- PRSP is prevalent in pediatric AOM in rural Kentucky, exhibiting resistance to common treatments.
- Recent antibiotic use is a strong risk factor for PRSP acquisition.
- Alternative antibiotics like clindamycin and vancomycin are effective against highly resistant strains.