Prevalence and predictors of spontaneous bacterial peritonitis due to ceftriaxone-resistant organisms at a large tertiary centre in the USA.

OBJECTIVES: The epidemiology of spontaneous bacterial peritonitis (SBP) due to ceftriaxone-resistant organisms has not been well studied in the USA. The primary objective of this study was to assess the prevalence and predictors of ceftriaxone-resistant SBP at a large US tertiary-care centre.

METHODS: This 1:1:4 case-case-control study included 141 adults with liver cirrhosis admitted from November 2011 to March 2016. Case group 1 were patients with SBP with a ceftriaxone-resistant organism (n=21). Case group 2 were patients with SBP with a ceftriaxone-susceptible organism (n=26). The control group were patients without SBP (n=94). Multiple logistic regression analysis was used to identify predictors of ceftriaxone-resistant SBP.

RESULTS: Fifty isolates were identified from 47 patients with culture-positive SBP (case groups 1 and 2). Of these 50 isolates, 32 (64%) were Gram-negatives [mostly Enterobacteriaceae (91%)], 15 (30%) were Gram-positives and 3 (6%) were Candida spp. The prevalence of ceftriaxone resistance in patients with culture-positive SBP was 45% (21/47). The most common ceftriaxone-resistant organisms were ESBL-producing Enterobacteriaceae (45%). Independent predictors of ceftriaxone-resistant SBP included duration of β-lactam therapy in the past 90days (aOR=1.07, 95% CI 1.01-1.13) and recent invasive gastrointestinal procedure (aOR=12.47, 95% CI 2.74-56.67).

CONCLUSIONS: The prevalence of ceftriaxone-resistant SBP was significant at a US tertiary centre. Local epidemiological data and identification of risk factors associated with ceftriaxone-resistant SBP, e.g. increased usage of previous β-lactam therapy and invasive gastrointestinal procedure, may help clinicians identify patients requiring alternative empirical antibiotics.