Spontaneous bacterial peritonitis caused by quinolone-resistant Escherichia coli: could steroid therapy play a role?

Role of host and bacterial virulence factors in Escherichia coli spontaneous bacterial peritonitis

OBJECTIVES

Host factors and bacterial virulence determinants may play a role in Escherichia coli (E. coli) spontaneous bacterial peritonitis. We evaluated the importance of these factors in the emergence of fluoroquinolone-resistant strains and outcome in cirrhotic patients with E. coli spontaneous bacterial peritonitis.

METHODS

E. coli spontaneous bacterial peritonitis was detected in a 2-year period in three tertiary hospitals. Clinical and bacteriological data were obtained. Phylogenetic group and 15 virulence genes of E. coli strains were analyzed by polymerase gene reaction and compared with 50 isolates from pyelonephritis patients.

RESULTS

Forty-seven E. coli spontaneous bacterial peritonitis patients were identified, 18 (38%) were fluoroquinolone-resistant, a 12% increase compared with our earlier series from 1997 to 2002. Fluoroquinolone resistance was associated with norfloxacin prophylaxis, increased resistance to trimethoprim-sulfamethoxazole and cefotaxime, and less bacterial virulence, as demonstrated by a higher prevalence of 'nonpathogenic' phylogenetic groups A+B1 (56 vs. 28%; P=0.04) and lower virulence scores in fluoroquinolone-resistant E. coli compared with fluoroquinolone-susceptible E. coli. E. coli strains from cirrhotic patients belonged more frequently to 'nonpathogenic' phylogenetic groups A+B1, had fewer virulence factors and higher rates of fluoroquinolone resistance than isolates from pyelonephytis patients. Immunosuppression was independently associated with in-hospital and 3-month mortality. Bacterial virulence factors were unrelated to mortality.

CONCLUSION

Fluoroquinolone-resistant E. coli spontaneous bacterial peritonitis prevalence is increasing because of norfloxacin prophylaxis. Strains from peritonitis are less virulent than strains from pyelonephritis because of a higher prevalence of A+B1 phylogeny and quinolone resistance. Mortality is related to immunosuppression, but not to bacterial virulence factors.

Leukotriene inhibitors in combination with steroids: potential role in the development of primary bacterial peritonitis

Leukotrienes play a role in inflammation, and their participation in airway inflammation and bronchoconstriction in patients with severe asthma can be ameliorated by a new class of drugs known as leukotriene modulators. The role of leukotrienes in increasing vascular permeability in experimental peritonitis and in inducing chemotaxis of inflammatory cells has recently been documented. Steroids have been incriminated in the development of bacterial translocation in animal models in association with the suppression of mucosal immunity. The development of spontaneous bacterial peritonitis is recognized in cirrhotic patients with ascites and in those with nephrotic syndrome. The onset of bacterial peritonitis in the absence of these predisposing conditions or other underlying cause, such as perforated viscus, is termed 'primary bacterial peritonitis', and has never been described in asthmatic patients. We present an asthmatic patient who developed primary bacterial peritonitis while receiving a leukotriene modulator in combination with prednisolone therapy. The hypothesis that leukotriene receptor blockade might predispose to the development of primary bacterial peritonitis in patients receiving steroid therapy is discussed.

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.