Hepatic abscess is frequently associated with hepatic artery thrombosis, which occurs in
up to 7% of patients (148). In one series, median time from transplant to hepatic abscess was
386 days (range 25–4198). Clinical presentation of hepatic abscess was similar to that described
in nonimmunosuppressed patients. Occasionally, the only manifestations are unexplained
fever and relapsing subacute bacteremia. In fact 40% to 45% of the liver abscesses are
associated with bacteremia. Prolonged antibiotic therapy, drainage, and even retransplantation
may be required to improve the outcome in these patients. Catheter drainage was successful in
70% of cases. Mortality rate was 42% (149). Ultrasonography or CT of the abdomen is the
normal technique to identify intra-abdominal or biliary infections. However, sterile fluid
collections are exceedingly common after liver transplantation, so an aspirate is necessary to
establish infection.
Mediastinitis
In heart and lung transplant recipients, the possibility of mediastinitis (2–9%) should be
considered. HT patients have a higher risk of postsurgical mediastinitis and sternal
osteomyelitis than other heart surgical patients (150). It may initially appear merely as fever
or bacteremia of unknown origin. Inflammatory signs in the sternal wound, sternal dehiscence,
and purulent drainage may appear later. The most commonly involved microorganisms are
staphylococci but gram-negative rods represent at least a third of our cases.Mycoplasma,
mycobacteria, and other less common pathogens should be suspected in culture-negative
wound infections (151,152). A bacteremia of unknown origin during the first month after HT
should always suggest the possibility of mediastinitis (153). Risk factors are prolonged
hospitalization before surgery, early chest reexploration, low output syndrome in adults and
the immature state of immune response in infants. Therapy consists of surgical debridement
and repair, and antimicrobial therapy given for three to six weeks.
Urinary Tract Infections
UTIs are the most common form of bacterial complication affecting renal transplant recipients
(154–156). The incidence in patients not receiving prophylaxis has been reported to vary from
5% to 36% in recent series (157,158). Pretransplant history of UTI increases the risk of infection
after transplantation (159). Some authors have found a cumulative incidence of acute
pyelonephritis (APN) after KT of 18.7%. The risk of developing APN was higher in female
(64%) than in male recipients, and correlated with the frequency of recurrent UTI and rejection
episodes. Multivariate analysis revealed that APN represents an independent risk factor
associated with the decline of renal function (p¼0.034) (160).
UTI, however, is not a common cause of ICU admission. The most common pathogens
includeEnterobacteriaceae, enterococci, staphylococci, andPseudomonas(161). Other less frequent
microorganisms likeSalmonella,Candida,orCorynebacterium urealyticumpose specific manage-
ment problems in this population (162). It is also important to remember the possibility of
infection caused by unusual pathogens likeMycoplasma hominis,M. tuberculosis, or BK and JC
viruses. Unless another source of fever is readily apparent, any febrile KT patient with an
abrupt deterioration of renal function should be treated with empiric antibacterial therapy
aimed at gram-negative bacteria, includingP. aeruginosa,after first obtaining blood and urine
cultures, especially in the first three months after transplantation (163). Examination of the iliac
fossa is particularly important after KT. Tenderness, erythema, fluctuance, or increase in the
allograft size may indicate the presence of a deep infection or rejection. Ultrasound or CT-
guided aspiration may facilitate the diagnosis. Prolonged administration of broad-spectrum
antimicrobial therapy has been classically recommended for the treatment of early infections,
although no double-blind, comparative study is available (155). Antimicrobial resistance to
drugs commonly used, such as cotrimoxazole or quinolones, is common, so they should not be
selected for empirical therapy of severe UTI (164,165).
Gastrointestinal Infections
Abdominal pain and/or diarrhea are detected in up to 20% of organ transplant recipients
(135). Gastrointestinal symptoms are present in up to 51% of HT patients in recent series,
398 Mun ̃oz et al.