Serotypes, antimicrobial resistance and genotypes of Streptococcus pneumoniae associated with infections in cancer patients in Brazil

- Pneumococcal isolates causing diseases in cancer patients were characterized.
- A large diversity of genotypes and capsular types were detected.
- Globally disseminated clones associated with resistance were found.
- Some genotypes seem to have a regional dissemination.
- Combined vaccination might reduce burden of pneumococcal diseases in such patients.

We sought to characterize pneumococcal isolates associated with bacteremia, pneumonia and meningitis in cancer patients and to estimate the coverage of the available pneumococcal vaccines. Fifty isolates recovered from 49 patients attending a cancer reference center over a 1-year period were analyzed. The prevalent serotypes were: 23F (12%), 6A (8%), 3, 4, 20, and 23A (6% each). All isolates were susceptible to chloramphenicol, levofloxacin, rifampicin, and vancomycin. Resistance or reduced susceptibility to penicillin made up 14%, and one isolate was also intermediately resistant to ceftriaxone. The three (6%) erythromycin-resistant isolates presented the M or cMLSB phenotypes and harbored the mef(A/E) gene exclusively or along with the erm(B) gene. Twenty-two (44%) isolates were closely related to 11 international clones, being strongly associated with penicillin non-susceptibility. Combined immunization with the 13-valent conjugate and the 23-valent polysaccharide vaccines might contribute to reduce (76%) the burden of the pneumococcal infections in the population investigated.