Risk factors for resistance to ceftriaxone and its impact on mortality in community, healthcare and nosocomial spontaneous bacterial peritonitis.

BACKGROUND & AIMS The recent emergence of third-generation cephalosporin resistance in spontaneous bacterial peritonitis is of great concern, although neither the risk factors for resistance nor its real impact on mortality have been well defined. METHODS We conducted a retrospective study of all spontaneous bacterial peritonitis episodes with positive blood and/or ascitic culture at our center (2001-2009). Episodes were classified according to the place of acquisition: community, healthcare system, or nosocomial. RESULTS Two hundred and forty-six episodes were analyzed in 200 patients (150 males, 57.3 years): 34.6% community-acquired, 38.6% healthcare system-acquired, and 26.8% nosocomially-acquired. Third-generation cephalosporin resistance occurred in 21.5% (7.1% community-acquired, 21.1% healthcare system-acquired, 40.9% nosocomially-acquired). These resistant cases were categorized as extended-spectrum β-lactamase-producing Gram-negative bacilli, other resistant Gram-negative bacilli, and Enterococci. Risk factors for resistance were previous use of cephalosporins, diabetes mellitus, upper gastrointestinal bleeding, nosocomial acquisition, and a low polymorphonuclear count in ascites. Regarding third-generation cephalosporin resistance, adequate empirical treatment was 80.7%. Independent predictors of mortality were nosocomial acquisition, poor hepato-renal function, immunosuppressive therapy, a marked inflammatory response during the episode and either third-generation cephalosporin-resistance or low rates of adequate empirical treatment. CONCLUSIONS The risk of third-generation cephalosporin resistance was particularly high in nosocomially-acquired episodes of spontaneous bacterial peritonitis, but also occurred in healthcare system-acquired cases. The extent of resistance and the adequacy of empirical antibiotics had a significant effect on mortality along with the patient's hepato-renal function. These data can help determine the most suitable empirical antimicrobial treatments in these patients.