CTX-M-15-H30Rx-ST131 subclone is one of the main causes of healthcare-associated ESBL-producing Escherichia coli bacteraemia of urinary origin in Spain.

OBJECTIVES: The objective of this study was to assess the prevalence and molecular epidemiology of ESBL-producing Escherichia coli causing healthcare-associated (HCA) and community-associated (CA) bacteraemia of urinary origin (BUO) in Spain. METHODS: An observational cohort study was conducted at eight hospitals from different Spanish geographical areas (2010-11). BUO episodes (n = 425) were classified as HCA (n = 215) and CA (n = 210), and one blood isolate per episode was collected. Susceptibility testing was performed, ESBLs were screened by double-disc diffusion test and ESBL and OXA-1 genes were characterized (PCR and sequencing). Population structure (phylogenetic groups, XbaI-PFGE and MLST) and ST131 subtyping (PCR) were determined. Virulence genes were detected by PCR and virulence score, profiles and extraintestinal pathogenic E. coli (ExPEC) status calculated. RESULTS: ESBL-producing E. coli prevalence was 9.2% (39/425). ESBL-producing E. coli episodes were significantly associated with HCA-BUO episodes [14% (30/215) versus 4.3% (9/210); P = 0.001]. The highest non-susceptibility proportions corresponded to ciprofloxacin (97.4%), amoxicillin/clavulanate (74.4%), co-trimoxazole (69.2%) and tobramycin (61.5%). Of the 39 ESBL-producing E. coli isolates, 34 produced CTX-M enzymes (21 CTX-M-15, 11 CTX-M-14 and 2 CTX-M-1). Fifteen STs were identified, the B2-ST131 clone being the most prevalent (54%; 21/39). All ST131 isolates were ExPEC and had the highest virulence scores, but they showed less diversity in virulence profiles than other STs. The H30Rx subclone accounted for most ST131 isolates (20/21), co-produced CTX-M-15 (20/20) and OXA-1 (19/20) enzymes and was associated with HCA episodes (16/20). CONCLUSIONS: The CTX-M-15-ST131-H30Rx subclone is a relevant MDR pathogen causing BUO, mainly HCA episodes. The dominance of this subclone with comparatively less diversity of virulence profiles reflects the spread of a successful and MDR ESBL ST131 lineage in Spain.

Risk factors for severe sepsis in community-onset bacteraemic urinary tract infection: impact of antimicrobial resistance in a large hospitalised cohort.

OBJECTIVE: To determine risks factors associated with severe sepsis or septic shock (SS) at admission in patients with community-onset bacteraemic urinary tract infection (CO-BUTI) including the impact of multidrug-resistant (MDR) bacteria. METHODS: We analysed a prospective cohort of all consecutive episodes of CO-BUTI requiring hospitalisation in 8 tertiary hospitals of Spain between October 2010 and June 2011. RESULTS: Of an overall of 525 CO-BUTI episodes, 175 (33%) presented with SS at admission. MDR bacteria were isolated in 29% (51/175) of episodes with SS and in 33% (117/350) of those without SS (p = 0.32). The main MDR microorganism was Escherichia coli in both groups (25% and 28% respectively). Independent risk factors associated with SS at admission were: having fatal underlying conditions, McCabe score II/III (OR 1.90; 95%CI 1.23-2.92; p = 0.004), presence of an indwelling urethral catheter (OR 3.01; 95%CI 1.50-6.03; p = 0.002) and a history of urinary tract obstruction (OR 1.56; 95%CI 1.03-2.34; p = 0.03). After considering interactions, indwelling urethral catheters were a risk factor only for patients without fatal underlying conditions. CONCLUSIONS: SS at hospital admission occurred in a third of CO-BUTI. Mainly host factors, and not the causative microorganisms or antimicrobial resistance patterns had an impact on the presence of SS.