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Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43
Published on: September 11, 2020
Antibiotic-resistant invasive pneumococcal clones in Italy
Giovanni Gherardi1, Loredana Fallico, Maria Del Grosso
1Department of Laboratory Medicine and Microbiology, Università Campus Biomedico, Rome, Italy.
Journal of Clinical Microbiology
|November 24, 2006
Summary
Multiple antibiotic-resistant Streptococcus pneumoniae clones were identified in Italy, including international and novel strains. Continuous monitoring is crucial, especially with nonvaccine serotypes emerging during the 7-valent pneumococcal conjugate vaccine era.
Area of Science:
- Microbiology
- Genetics
- Epidemiology
Background:
- Invasive pneumococcal disease remains a public health concern.
- Understanding the genetic diversity and antibiotic resistance patterns of Streptococcus pneumoniae is essential for effective disease control.
- The introduction of pneumococcal conjugate vaccines (PCVs) has impacted serotype distribution and resistance.
Purpose of the Study:
- To genetically characterize multiple antibiotic-resistant invasive pneumococcal isolates from Italy.
- To identify prevalent international and novel clones among penicillin-nonsusceptible (PNSSP) and penicillin-susceptible (PSSP) Streptococcus pneumoniae strains.
- To investigate the presence of nonvaccine serotypes and capsular switching.
Main Methods:
- Pulsed-field gel electrophoresis (PFGE) for genetic profiling.
- Multilocus sequence typing (MLST) for clonal analysis.
- Analysis of pbp2b and pbp2x genes in PNSSP isolates.
Main Results:
- Identification of several international clones (e.g., Spain(23F)-1/ST81, Sweden(15A)-25/ST63) among PNSSP isolates.
- Discovery of novel clones, including those with nonvaccine serotypes (serotype 3 and 15B/C).
- Observation of capsular switching involving both vaccine and nonvaccine serotypes (e.g., 15B/C, 19A).
- An unusual finding included a deletion in the xpt gene preventing MLST profiling in one isolate.
Conclusions:
- Multiple antibiotic-resistant pneumococcal clones, including international and novel ones, circulate in Italy.
- Nonvaccine serotypes are present among resistant clones, highlighting the need for ongoing surveillance.
- Capsular switching contributes to the evolving epidemiology of pneumococcal disease.
- Continuous monitoring of pneumococcal epidemiology is vital in the PCV7 era to guide public health interventions.
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