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

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.

Predictors of Mortality in Bloodstream Infections Caused by Pseudomonas aeruginosa and Impact of Antimicrobial Resistance and Bacterial Virulence

“…While this association has been shown in our hospital, the coincidence of the O4 and O11 serotypes with ST175 and ST235 international high-risk clones could make these observations of interest in many other locations (19,27,28). In fact, in a recent Spanish nationwide study, including 1445 P. aeruginosa isolates, Del Barrio-Tofiño and colleagues found that O4 and O11 serotypes are linked to the MDR/XDR profile of widespread ST175 and ST235 clones, respectively (29). The strength of our multivariate analysis is reinforced by its adjustment with other relevant variables also influencing a patient's prognosis.…”

Distribution of serotypes and antibiotic resistance of invasive Pseudomonas aeruginosa in a multi-country collection

“…Studies have shown that isolates belonging to serotypes O1, O6, O11, and O12 account for > 65% of the P. aeruginosa infections [ 12 , 13 ] and serotype O4 and O12 isolates are more frequently associated with resistance to various classes of antibiotics [ 14 , 15 ]. Serotyping data indicates that P. aeruginosa isolates of serotypes O5, O6 and O11 are prevalent in burn wound infections [ 16 ] and O6 and O11 are the most prevalent serotypes in pneumonia [ 17 , 18 ].…”

New Sequence Type ST3449 in Multidrug-Resistant Pseudomonas aeruginosa Isolates from a Cystic Fibrosis Patient

“…Earlier studies have also shown the presence of serotype O6 among CF P. aeruginosa isolates [ 16 , 17 ], which is often associated with poor clinical outcomes [ 6 ]. A recent Spanish national survey demonstrated that O6 was among the most prevalent serotypes in the population studied [ 18 ].…”