Liver abcesses are usually treated with a combination of drainage (percutaneous preferred over surgical) and antibiotics. Drainage is paramount, but there are exceptions, like small, immature abcesses can respond to antibiotics only; and amoebic abcesses that can be treated with metronidazole only. 

The choice of pharmacological therapy for liver abcesses depends on the clinical context. Is there previous biliary infection (cholecystitis / cholangitis)? Is there recent colo-rectal infection (acute appendicitis / diverticulits)? Is the patient immunocompromised?

The choice of antibiotics would depend on these factors. Surely coverage of Enterobacteriacea and possibly anaerobes in case of colo-rectal condition. Piperacillin-tazobactan or ertapenem are excellent choices in my experience but it also depends on your institution patterns of bacterial resistance. If immunocompromised remenber the possiility of fungal infection (ex: Candida spp.).

Again, pharmacological treatment is usually adjuvant to drainage Percutaneous CT or US-guided is the gold standard.

Bes regards,

Henrique

Totally agree with Alexandrine. Drainage is an eventuality in treating large liver abscesses; if not sooner , it will be later. 

Pyogenic hepatic abscesses generally occur in middle-aged adults. The patients may present with fever, abdominal pain +  tenderness with hepatomegaly. Majority of the abscesses involve in the right hepatic lobe (~75%). About half of the liver abscess develop from biliary tract (cholangitis). 

Long term antibiotics together with abscess drainage (either CT or US-guided) is the optimal therapy for pyogenic liver abscesses,  and is suggested for at least one week with CT follow-up. Surgical drainage may be considered if complex abscess, multiple abscesses, percutaneously unreachable abscess, larger abscesses (> 5 cm).

Empiric antibiotic coverage should include Enterobacteria, enterococci, anaerobes, and in certain situations staphylococci and streptococci. Antifungal treatment in immunosuppressed patients at risk.

In our setting,

Ampicillin 2g q6h plus gentamicin 1.7mg/kg IV q8h plus metronidazole 0.5g IV q8h 

OR

Cefotaxime 2.0g IV q8h or ceftriaxone 2.0g IV q24h plus metronidazole 0.5g IV q8h

OR

Tazocin 3.375g IV q 6h

Metronidazole should be added on, if amebic liver abscess a possibility.

Carbapenems esp. if the patient is at high risk for resistant .

Oral fluroquinolones are often used for prolonged therapy after completion of initial IV therapy course.

Ciprofloxacin/levofloxacin plus metronidazole

Duration: 

Often 4-6 weeks total.