Role of immunosuppression in the development of quinolone-resistant Escherichia coli spontaneous bacterial peritonitis and in the mortality of E. coli spontaneous bacterial peritonitis.

BACKGROUND

Norfloxacin decreases the incidence of spontaneous bacterial peritonitis in cirrhotics, but promotes the appearance of quinolone-resistant Escherichia coli.

AIM

: To define the characteristics of quinolone-resistant E. coli spontaneous bacterial peritonitis.

METHODS

E. coli-positive ascitic fluid cultures were identified during a 6-year period. Data on quinolone-sensitive and quinolone-resistant E. coli spontaneous bacterial peritonitis were compared.

RESULTS

One hundred and two E. coli-positive ascitic fluid cultures were detected. Cirrhotics accounted for 67 cases. Spontaneous bacterial peritonitis was found in 47 of the 67 (70%) cases [35 (74%) caused by quinolone-sensitive and 12 (26%) caused by quinolone-resistant E. coli]. Norfloxacin prophylaxis was higher in the quinolone-resistant group (92% vs. 6%, P < 0.001). Compared with patients with quinolone-sensitive E. coli spontaneous bacterial peritonitis, those with quinolone-resistant E. coli spontaneous bacterial peritonitis showed a higher prevalence of associated immunosuppressive factors (immunosuppressive drugs, human immunodeficiency virus infection or cancer) (92% vs. 20%, P < 0.001). Steroid therapy was independently associated with quinolone-resistant E. coli spontaneous bacterial peritonitis (odds ratio, 49; 95% confidence interval, 3.4-699; P = 0.004). The Child-Pugh score (P = 0.03), immunosuppression (P = 0.02) and renal failure (P = 0.01) were independent predictors of E. coli spontaneous bacterial peritonitis-related mortality.

CONCLUSIONS

Associated immunosuppression is an important co-factor for the development of quinolone-resistant E. coli spontaneous bacterial peritonitis and for E. coli spontaneous bacterial peritonitis-related mortality.