Association between Pseudomonas aeruginosa O-antigen serotypes, resistance profiles and high-risk clones: results from a Spanish nationwide survey
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 ,   GEMARA-SEIMC/REIPI, Galán Fátima , Gracia Irene , Rodríguez Manuel Antonio , Martín Lina , Sánchez Juan Manuel , Viñuela Laura , García Mª Victoria , Lepe José Antonio , Aznar Javier , López-Hernández Inma , Seral Cristina , Castillo-García Francisco Javier , López-Calleja Ana Isabel , Aspiroz Carmen , de la Iglesia Pedro , Ramón Susana , Riera Elena , Pérez María Cruz , Gallegos Carmen , Calvo Jorge , Quesada María Dolores , Marco Francesc , Hoyos Yannick , Horcajada Juan Pablo , Larrosa Nieves , González Juan José , Tubau Fe , Capilla Silvia , Pérez-Moreno Mar Olga , Centelles Mª José , Padilla Emma , Rivera Alba , Mirelis Beatriz , Rodríguez-Tarazona Raquel Elisa , Arenal-Andrés Noelia , del Pilar Ortega María , Megías Gregoria , García Inmaculada , Colmenarejo Cristina , González José Carlos , Martínez Nora Mariela , Gomila Bárbara , Giner Salvador , Tormo Nuria , Garduño Eugenio , Agulla José Andrés , Seoane Alejandro , Pita Julia , Vidal Isabel Paz , Guzmán David Mauricio , García Marta , Pérez del Molino María Luisa , Barbeito Gema , Artiles Fernando , Azcona-Gutiérrez José Manuel , Sáenz Yolanda , Oteo José Antonio , González Ana , Villa Jennifer , Chaves Fernando , Cercenado Emilia , Alarcón Teresa , Zurita Nelly Daniela , Merino Irene , Morosini María Isabel , Cantón Rafael , Sánchez María Isabel , Moreno Laura , Yagüe Genoveva , Leiva José , Barrios José Luis , Canut Andrés , Oteo Jesús 
Published: July 2019

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.