Case Presentation: A 65 year-old male with a history of chronic alcoholism presented to a regional hospital with progressive fatigue and epigastric pain. The patient was diagnosed with decompensated alcoholic cirrhosis with gallstone pancreatitis, which required placement of a biliary stent and empiric antibiotics; his prolonged hospital course was complicated by aspiration pneumonia, and stent removal following occlusion. Ascitic fluid analysis identified no infection; thus, percutaneous endoscopic gastrostomy (PEG) tube was inserted for nutrition in lieu of his aspiration risk. However, as ascitic fluid leakage was observed around the PEG insertion site, the patient was transferred to our academic facility for further management.
Upon transfer, the patient had a constellation of physical exam findings notable for decompensated cirrhosis and leaking ascites with anasarca. The laboratory tests were remarkable for WBC 20,000/mcl, serum creatinine 0.55 mg/dl, AST 201 U/L, ALT 74 U/L, alkaline phosphatase 458 U/L, total bilirubin 9.0 mg/dl, albumin 1.8 g/dl and INR 1.5. Ascitic fluid analysis confirmed piperacillin-tazobactam (P/T) susceptible Achromobacter Xylosoxidans (AX) as the infectious etiology, with increased neutrophil count. Empiric regimen of cefepime, metronidazole and vancomycin was narrowed to P/T. After five days of treatment with P/T, however, his abdomen demonstrated peritoneal signs with increased ascites. Repeat paracentesis confirmed worsening bacterial peritonitis. Despite broadened antimicrobial coverage with meropenem and vancomycin, the patient deteriorated and was deceased within twenty-four hours of intensive care unit transfer. The ascitic fluid culture identified vancomycin-resistant Enterococcus and AX, with developed resistance to P/T.

Discussion: Bacterial peritonitis due to AX has been reported primarily in the setting of peritoneal dialysis. In our patient case, the recently placed PEG tube with ascitic fluid leakage was identified as the most plausible infection source. While the management of secondary peritonitis involving biliary stent and PEG tube would generally include surgical intervention for infection source control with broad spectrum antibiotics targeting nosocomial coverage per Infectious Disease Society of America, the antimicrobial coverage may yet be inadequate for widely resistant and potentially inducible Achromobacter species. In addition, as these pathogens are generally identified in polymicrobial infections, their presence may serve as a surrogate marker of unfavorable outcomes.

Conclusions: Achromobacter Xylosoxidans, although a rare peritonitis pathogen, may be associated with wide antimicrobial resistance and unfavorable outcomes. Thus, clinicians should consider empirical broad antimicrobial regimen, with AX coverage, if any concern for secondary peritonitis associated with PEG placement exists. Moreover, repeat ascitic fluid culture may be beneficial in verifying continued susceptibility of selected definitive antibiotics.