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Characterization of Streptococcus pneumoniae from human immunodeficiency virus--seropositive patients with acute and
1Public Health Laboratory, John Radcliffe Hospital, Headington, Oxford, United Kingdom.
Abstract:
Thirty-two isolates of clinically significant Streptococcus pneumoniae from 11 human immunodeficiency virus (HIV)-seropositive patients with single or multiple episodes of pneumonia were characterized by antibiotic susceptibility testing, serotyping, ribotyping, and repetitive extragenic palindromic polymerase chain reaction (REP-PCR). The isolates comprised 10 serotypes, 12 ribotyping patterns, and 12 REP-PCR patterns. There was close but not absolute correlation between techniques. By combining these characterization methods, 14 strains were identified. Five strains were found in > 1 patient, suggesting their frequent occurrence in this population. Two isolates of different serotype from 1 patient were highly related by ribotyping and REP-PCR, suggesting possible in vivo serotype change. Acute infection was associated with single strains or coinfection by distinct strains. Recurrent pneumonia was identified as relapse with the same strain or reinfection with new strains. The molecular characterization of pneumonococci from HIV-seropositive persons refines our understanding of pneumonococcal infection in these patients.
Insights
Molecular typing identified 14 distinct Streptococcus pneumoniae strains in HIV-positive patients with pneumonia. Some strains frequently infected multiple individuals, and evidence suggests in vivo serotype switching may occur.
Area of Science:
- Microbiology
- Infectious Diseases
- Immunology
Background:
- Streptococcus pneumoniae is a leading cause of pneumonia, particularly in individuals with human immunodeficiency virus (HIV).
- Understanding pneumococcal infection dynamics in HIV-seropositive populations is crucial for effective prevention and treatment strategies.
Purpose of the Study:
- To molecularly characterize Streptococcus pneumoniae isolates from HIV-seropositive patients experiencing pneumonia.
- To investigate the genetic relatedness of pneumococcal strains and identify common or recurrent strains within this patient group.
Main Methods:
- Antibiotic susceptibility testing, serotyping, ribotyping, and repetitive extragenic palindromic polymerase chain reaction (REP-PCR) were employed.
- These techniques were used to analyze 32 Streptococcus pneumoniae isolates from 11 HIV-seropositive patients.
Main Results:
- Ten serotypes, 12 ribotyping patterns, and 12 REP-PCR patterns were identified among the isolates.
- Combining methods revealed 14 distinct strains, with five strains found in multiple patients, indicating frequent circulation.
- Close correlation between typing methods was observed, aiding in strain identification and suggesting potential in vivo serotype switching in one patient.
Conclusions:
- Molecular characterization provides a refined understanding of pneumococcal infection in HIV-seropositive individuals.
- Findings highlight the presence of prevalent pneumococcal strains and suggest complex infection patterns including relapse and reinfection.