Genetic background of Escherichia coli isolates from patients with spontaneous bacterial peritonitis: relationship with host factors and prognosis

Abstract

Spontaneous bacterial peritonitis (SBP) is a severe complication in patients with cirrhosis and ascites. It is predominantly caused by Escherichia coli. The phylogenetic group and virulence genotype of E. coli isolates causing SBP were investigated, and the association of these characteristics with host factors and prognosis was examined. Seventy-six episodes of E. coli SBP that occurred over a 9-year period were studied. The phylogenetic group of the isolates and the presence of 36 virulence factor genes were investigated. The influence of bacterial and host factors on in-hospital mortality was assessed by multiple logistic regression. Phylogenetic groups A, B1, B2 and D were found in 26%, 4%, 46% and 24% of the isolates, respectively. Virulence factor genes were more frequent in B2 isolates than in non-B2 isolates (mean virulence score 15.4 vs. 7.3, p <10(-4)). Ciprofloxacin resistance was significantly associated with non-B2 groups and a low virulence score. Host factors independently associated with a shift from B2 to non-B2 isolates were norfloxacin prophylaxis (OR 13.01, p 0.0213) and prothrombin ratio (OR 1.04 for a 10% decrease, p 0.0211). The model for end-stage liver disease (MELD) score (OR 1.83, p 0.0007) and hospital-acquired SBP (OR 4.13, p 0.0247) were independent predictors of in-hospital mortality. In contrast, outcome was not influenced by the phylogenetic group or the virulence profile. These findings indicate that the characteristics of E. coli isolates causing SBP vary with the severity of liver disease and with fluoroquinolone prophylaxis. Host factors are more important than bacterial factors in predicting in-hospital mortality.

Major Differences Exist in Frequencies of Virulence Factors and Multidrug Resistance between Community and Nosocomial Escherichia coli Bloodstream Isolates

“…Previous investigations showed that FQ r isolates are associated with lower VF prevalences than FQ s isolates. An exception was for iutA, which was universally detected at a higher frequency in FQ r isolates (2,27,38,41,42,47). Although we found that more FQ r isolates belonged to phylogenetic group B2, they were proportionally less prevalent in this group than in group D. Previous studies of these particular relationships have produced conflicting results (2,27,38).…”

“…The majority of isolates belonged to phylogenetic groups B2 and D. While similar observations have been made with ExPEC strains originating from patients with bacteremia (26, 36, 42, 46), the urinary tract (24,25,35,41,43), both of these (4, 22, 37), or different sources (2,20,27), others have reported that ExPEC strains from the urinary tract and patients with bacteremia fall predominantly into phylogenetic groups A (15) and D (34), respectively. The study design and the number and source of the isolates, along with demographic and epidemio- logic factors relating to the patient population, probably account for these discordant results.…”

“…An exception was for iutA, which was universally detected at a higher frequency in FQ r isolates (2,27,38,41,42,47). Although we found that more FQ r isolates belonged to phylogenetic group B2, they were proportionally less prevalent in this group than in group D. Previous studies of these particular relationships have produced conflicting results (2,27,38). The concentrated prescription of ciprofloxacin in our hospital may have progressively selected for ciprofloxacin-resistant E. coli mutants, which would explain the greater proportion of ciprofloxacin-resistant isolates detected in NA bacteremias than in those from the community.…”

Genetic Diversity and Virulence Profiles of Escherichia coli Isolates Causing Spontaneous Bacterial Peritonitis and Bacteremia in Patients with Cirrhosis

“…Although prophylaxis with norfloxacin is recommended in patients at high risk of infection, this may promote the emergence of fluoroquinolone-resistant organisms (3,29). Screening patients for the presence of translocating isolates in the gut could help identify those who would benefit the most from norfloxacin prophylaxis.…”

Phylogenetic Grouping and Phenotypic Detection of Extended-Spectrum β-Lactamases Among Escherichia coli From Calves and Dairy Cows in Khuzestan, Iran

“…1,2 Phylogenetic analyses have shown that E. coli strains are located in 4 main phylogenetic groups (A, B1, B2, and D) and the strains differ in phenotypic characteristics including antibioticresistance patterns, and resistance to special antibiotics can be related to particular phylogenetic groups. [3][4][5][6] The World Health Organization (WHO) reported that approximately 50% of the universally produced antibiotics are consumed for veterinary usages such as prophylactic and growth promotion purposes. [7][8][9] The increase of antibiotic resistance following the use of antibiotics such as beta-lactams and growing the commensal and pathogenic ESBL (extended-spectrum beta-lactamase)-producing bacteria like E. coli strains especially in foodproducing animals pose a threat to the public health and food safety.…”