Association between Pseudomonas aeruginosa O-antigen serotypes, resistance profiles and high-risk clones: results from a Spanish nationwide survey

• Published in: Journal of antimicrobial chemotherapy 2019-11, Vol.74 (11), p.3217-3220
• Main Authors: del Barrio-Tofiño, Ester, Sánchez-Diener, Irina, Zamorano, Laura, Cortes-Lara, Sara, López-Causapé, Carla, Cabot, Gabriel, Bou, Germán, Martínez-Martínez, Luis, Oliver, Antonio
• Format: Article
• Language: English
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkz346

Abstract Objectives To evaluate the correlation of O-antigen serotypes with resistance profiles and high-risk clones in a Spanish nationwide survey. Methods Up to 30 consecutive healthcare-associated Pseudomonas aeruginosa isolates were collected during October 2017 from each of 51 hospitals (covering all Spanish regions) with a total of 1445 isolates studied. MICs of 13 antipseudomonal agents and MDR/XDR profiles had been previously determined, as well as whole-genome sequences of 185 representative XDR isolates. O-antigen serotypes (O1–O16) were determined by agglutination using serotype-specific antisera (BioRad). The Pseudomonas aeruginosa serotyper (PAst) program was used for in silico serotyping. Results The most frequent serotypes were O6 (17.8%), O1 (15.4%) and O11 (13.3%). In contrast, the most frequent serotype among XDR isolates (17.3%) was O4 (34.1%), distantly followed by O11 (15.9%). Within serotypes, XDR phenotypes were more frequent for O12 (60.0%) and O4 (57.3%). The most frequent clone among the XDR isolates was ST175 (40.9%), followed by CC235 (10.7%), ST308 (5.2%) and CC111 (3.6%). Up to 81.6% of XDR ST175 isolates typed O4, whereas 18.4% were non-typeable. O4 genotype was detected in all sequenced (n=55) ST175 isolates. On the other hand, CC235 and ST308 were associated with O11, whereas CC111 was linked to serotype O12. Conclusions O4 serotype is linked to the MDR/XDR profile of widespread ST175 (typically only susceptible to colistin, amikacin and the novel combinations ceftolozane/tazobactam and ceftazidime/avibactam) and therefore, after local validation, its detection in the microbiology laboratory might be useful for guiding semi-empirical antipseudomonal therapies and infection control measures in Spanish hospitals.