Liver abscess is usually a polymicrobial infection, with Escherichia coli, enterobacteriaceae, anaerobes, and streptococci being the most commonly reported causative organisms [6,7]. However, there has been an increase in the number of cases of liver abscess due to Klebsiella pneumoniae, in both Asian countries and the US [8].This infection was first reported in Taiwan in 1986, and now Klebsiella has become the most common causative agent for liver abscess in Asian countries [9]. The etiology of the infection is unclear, but some studies show that translocation of Klebsiella pneumoniae from the gastrointestinal tract may be the most likely route for the bacteria causing liver abscess [10]. Presence of diabetes or impaired fasting glucose is the most common predisposing factor for developing KLA and metastatic infection. The other risk factors for developing KLA include fatty liver disease, recent use of antibiotics (which was the sole risk factor in our patient), and highly virulent strains of Klebsiella (K1 capsular serotype) [4].

The most common presenting symptom of KLA is fever, which is present in approximately 95% cases. Other signs and symptoms include chills, nausea, vomiting, diarrhea, right upper quadrant pain and tenderness, and jaundice. Laboratory abnormalities include elevation of serum AST, ALT, bilirubin, and alkaline phosphatase. Liver abscesses due to Klebsiella are more likely to be solitary and monomicrobial, but multiple liver abscesses can also occur, as in our patient [11]. Hematogenous spread and metastatic infection can occur in 10–45% patients, particularly in patients with diabetes mellitus [12]. Endophthalmitis is the most common and one of the very serious complication of metastatic infection and can lead to visual impairment. Other metastatic complications include meningitis, brain abscess, septic pulmonary emboli, splenic abscess, psoas abscess, neck abscess, and osteomyelitis.

Ultrasound and CT scan are the tests of choice when liver abscess is suspected based on clinical signs and symptoms and laboratory abnormalities. Final diagnosis is made by cultures from the abscess aspirate. The sample should be sent for gram stain and both aerobic and anaerobic cultures. Blood cultures should also be obtained in all patients with KLA as it can cause bacteremia [13].

Treatment of KLA consists of drainage of the abscess and systemic antibiotics. Percutaneous drainage is the modality of choice for KLA and is preferred over surgical drainage. It includes percutaneous aspiration and percutaneous catheter drainage. Surgical drainage is reserved for patients in which the abscess in not amenable to percutaneous drainage, thick pus is present which cannot be aspirated, patients with multiple large liver abscesses, patients with persistent sepsis and fever even after antibiotics and percutaneous drainage, a multiloculated abscess which cannot be adequately drained percutaneously, an abscess in left lobe, and a ruptured abscess. All patients require systemic antibiotic therapy in addition to the drainage. Empiric antibiotics therapy should have coverage for gram-negative bacteria and anaerobes, which is the empiric coverage for any pyogenic liver abscess. Once the susceptibility results are back, antibiotics should be adjusted accordingly. Third generation cephalosporins are the preferred choice of antibiotics for KLA. Patients with diabetes mellitus have a high likelihood of developing drug resistant K. pneumoniae infection. If there is high suspicion of Extended-Dpectrum Beta-Lactamase (ESBL) producing bacteria, then carbapenems should be given empirically until the culture and susceptibility results are back [14]. Duration of antibiotic therapy is unclear, but most cases require 4–6 weeks of treatment. Intravenous antibiotics can be given for first 2–3 weeks until the patient improves clinically, and the rest of the course can be completed with oral agents. Longer courses may be required in patients with persistent radiographic findings of abscess and in patient requiring subsequent drainage procedures. Treatment should usually be continued until complete or near complete resolution of the abscess on CT.

KLA has an overall good prognosis if diagnosed early and treated adequately, but patients with metastatic infection especially endophthalmitis have a poor prognosis and cause significant morbidity [15].