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Penicillin-resistant Streptococcus pneumoniae in Argentina: frequent occurrence of an internationally spread serotype
1Servicio Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas, A.N.L.I.S, Dr. C. Malbrán, Buenos Aires, Argentina.
Insights
Penicillin-resistant Streptococcus pneumoniae (SPN) strains in Argentinian children are often linked to the International Spanish/French clone. Over 80% of these resistant SPN isolates in Argentina appear imported, highlighting clonal spread in South America.
Area of Science:
- Microbiology
- Epidemiology
- Infectious Diseases
Background:
- Streptococcus pneumoniae (SPN) causes invasive infections in children globally.
- Antimicrobial resistance in SPN is a growing public health concern.
- Understanding the epidemiology of SPN serotypes and resistance is crucial for effective control.
Purpose of the Study:
- To determine the prevalence of SPN capsular types and antimicrobial resistance patterns in invasive infections among children under 5 years old in Latin America.
- To investigate the genetic relatedness and clonal origins of penicillin-resistant SPN isolates in Argentina.
Main Methods:
- Epidemiological surveillance across six Latin-American countries.
- Analysis of SPN isolates from children under 5 years of age.
- Antimicrobial susceptibility testing, including penicillin resistance.
- Pulsed-field gel electrophoresis (PFGE) for chromosomal DNA fingerprinting of SPN isolates.
Main Results:
- In Argentina, 24.4% of SPN isolates showed penicillin resistance (PR), significantly associated with serotype 14.
- Eighty-two percent of PR SPN isolates in Argentina shared characteristics with the International Spanish/French clone (clone B), predominantly expressing serotype 14.
- Penicillin-susceptible SPN isolates exhibited significant diversity in serotypes and genetic patterns.
- Data suggest over 80% of PR SPN isolates in Argentina were imported.
Conclusions:
- The International Spanish/French clone is a major contributor to penicillin resistance in SPN infections among children in Argentina.
- The findings underscore the significant role of geographic clonal spread in the epidemiology of SPN in South America.
- Targeted interventions may be needed to address the importation and spread of resistant SPN clones.
Abstract:
Six Latin-American countries participated in an epidemiological surveillance study conducted by the Pan American Health Organization in order to determine the relative prevalence of capsular types and antimicrobial resistance patterns of Streptococcus pneumoniae (SPN) causing invasive infections in children <5 years of age. In Argentina, the incidence of penicillin resistance (PR) was 24.4%, and it was significantly associated with serotype 14 (p < 0.001). The chromosomal DNA of 56 of those SPN isolates, 39 PR and 17 susceptible, was digested with SmaI and resolved by PFGE. Eighty-two percent (32/39) of the PR isolates shared characteristics with the widely spread International Spanish/French clone (clone B). All members of clone B except one expressed serotype 14, with the exception of one isolate that expressed serotype 19F and probably resulted from an in vivo capsular transformation event. Only a single isolate shared features with the 23F International Spanish/USA clone (clone A). The 17 penicillin-susceptible (PS) SPN isolates presented an enormous degree of variation in the chromosomal background, expressing 12 serotypes and 13 PFGE patterns. The data suggest that over 80% of the SPN-PR isolates in Argentina were imported, and this confirms the importance of the geographic spread of SPN clones in South America.