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Capsular Serotyping of Streptococcus pneumoniae Using the Quellung Reaction
Published on: February 24, 2014
A novel multiresistant Streptococcus pneumoniae serogroup 19 clone from Washington State identified by pulsed-field
V A Luna1, D B Jernigan, A Tice
1Department of Pathobiology, University of Washington, Seattle, WA 98195-7238, USA.
Abstract:
In 1997, a cluster of multiresistant invasive serogroup 19 pneumococcus infections, including two fatalities, was reported in Washington State. Further investigation identified other cases. Fourteen Washington Streptococcus pneumoniae isolates, four from Alaska, and eight isolates from eastern Canada with reduced penicillin susceptibility (MIC of > or =1 microg/ml) were included in the study. Pulsed-field gel electrophoresis (PFGE) with ApaI, SacII, and SmaI restriction enzymes and IS1167 and mef restriction fragment length polymorphism (RFLP) pattern analysis were performed. Twenty of the 26 isolates had identical or related PFGE patterns, with two or all three enzymes, and identical or related IS1167 RFLP patterns, indicating that they were genetically related. These 20 isolates contained the mef gene conferring erythromycin resistance and had identical mef RFLP patterns. The PFGE and RFLP patterns were distinct from those of six multiresistant clones previously described and suggest that a new multiresistant clone has appeared in Washington, Alaska, and eastern Canada. This newly characterized clone should be included in the Pneumococcal Molecular Epidemiology Network.
Insights
A new multiresistant clone of Streptococcus pneumoniae (pneumococcus) emerged in Washington, Alaska, and Canada. Genetic analysis confirmed its distinctness and spread, necessitating its inclusion in molecular epidemiology networks.
Area of Science:
- Microbiology
- Molecular Epidemiology
- Infectious Diseases
Background:
- A 1997 outbreak of multiresistant invasive serogroup 19 pneumococcus in Washington State, USA, resulted in fatalities.
- Further investigation revealed additional cases and isolates from Alaska and eastern Canada with reduced penicillin susceptibility.
Purpose of the Study:
- To genetically characterize invasive Streptococcus pneumoniae isolates from Washington, Alaska, and eastern Canada.
- To determine if the isolates represented a new or previously described multiresistant clone.
Main Methods:
- Pulsed-field gel electrophoresis (PFGE) using ApaI, SacII, and SmaI restriction enzymes.
- IS1167 and mef restriction fragment length polymorphism (RFLP) pattern analysis.
- Identification of the mef gene conferring erythromycin resistance.
Main Results:
- Twenty of 26 isolates exhibited identical or related PFGE and IS1167 RFLP patterns, indicating genetic relatedness.
- These 20 isolates possessed the mef gene and identical mef RFLP patterns, confirming erythromycin resistance.
- The characterized clone's genetic patterns were distinct from six previously described multiresistant clones.
Conclusions:
- A novel multiresistant clone of Streptococcus pneumoniae has emerged and spread across Washington, Alaska, and eastern Canada.
- This newly identified clone requires inclusion in the Pneumococcal Molecular Epidemiology Network for surveillance.
- The findings highlight the importance of ongoing molecular surveillance for emerging antibiotic-resistant pathogens.
