Changing Bacterial Profiles and Antibiotic Susceptibility Patterns in Spontaneous Ascites Infection: A Shift in Empiric Combination Antibiotic Therapy?

Background/

Objectives

This study aimed to determine bacteria that grow in spontaneous ascites infection and their antibiotic susceptibility. Materials and

Methods

A total of 291 cases of cirrhosis-related ascites were retrospectively analyzed between January 2007 and September 2015. Simple ascites, spontaneous ascites infection, spontaneous bacterial peritonitis, and culture results were recorded. Due to increasing antibiotic resistance, theoretically appropriate antibiotics were paired, and their susceptibility was evaluated in order to review our empirical antibiotic choices and evaluate new empirical treatment options.

Results

In all cultures, 48.1% were Gram-positive cocci and 50.6% were Gram-negative bacilli. Multidrug-resistant bacteria grew in 16 cultures (22.2%). The most common bacterium was Escherichia coli, and the second most common bacteria were coagulase-negative staphylococci (CoNS). According to all culture data, the rate of antibiotic susceptibility was third- and fourth-generation cephalosporins between 76.4 and 68%, 68% for ampicillin-sulbactam, 81.8% for piperacillin-tazobactam, 66% for ciprofloxacin, 71% for levofloxacin, 30% for tetracycline, and 45% for penicillin. Beta-lactam group antibiotic susceptibility of CoNS was 25% for penicillin and 53% for ampicillin-sulbactam; 52% had methicillin resistance. The rate of resistance to quinolones was 35%. Multidrug resistance was detected in 40% of CoNS (eight cases). When theoretically appropriate antibiotics were paired, combination therapy increased the susceptibility rates.

Conclusions

The increase in Gram-positive infections and resistance to other antibiotic groups indicates empirical antibiotic selection based on local microbial culture results and antibiotic susceptibility. Our results are crucial to allowing for more rational and successful use of antibiotics.