Primary prophylaxis for spontaneous bacterial peritonitis is linked to antibiotic resistance in the Veterans Health Administration

Spontaneous bacterial peritonitis (SBP) is a major cause of mortality. Although SBP primary prophylaxis (SBPPr) with fluoroquinolones and trimethoprim-sulfamethoxazole (TMP-SMX) is often used, resistance could reduce its benefit. Aim: Analyze peritoneal fluid resistance patterns in patients with a first SBP episode with/without SBPPr using the Veterans Health Administration corporate data warehouse and to evaluate national antibiograms. Corporate data warehouse data were extracted using validated International Classification of Disease-9/10 codes, culture, resistance data, and outcomes of 7553 patients who developed their first inpatient SBP between 2009 and 2019 and compared between those with/without SBPPr. Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) sensitivity to ciprofloxacin and TMP-SMX was calculated using 2021 Veterans Health Administration antibiogram data from all states. The most common isolates were E. coli, K. pneumoniae, and Staphylococcus species. Veterans taking ciprofloxacin SBBPr had higher fluoroquinolone resistance (34% vs 14% no SBPPr, p<0.0001); those taking TMP-SMX had higher TMP-SMX resistance (40% vs 14%, p<0.0001). SBPPr patients showed higher culture positivity, greater length of stay, higher second SBP, and higher probability of liver transplant rates versus no SBPPr. Multivariable models showed SBBPr to be the only variable associated with gram-negative resistance, and SBPPr was associated with a trend toward longer length of stay.E. coli ciprofloxacin sensitivity rates were 50%-87% and 43%-92% for TMP-SMX. K. pneumoniae ciprofloxacin sensitivity was 76%-100% and 72%-100% for TMP-SMX. Conclusion: Among patients who developed their first SBP episode, there was a higher prevalence of antibiotic resistance in those on SBPPr, with a high rate of fluoroquinolone resistance across the Veterans Health Administration sites.