patients if an overload exposure has occurred (39). Accordingly, ICUs caring for transplant
patients should maintain a good quality of air control (105).Aspergillusmay appear late after
transplantation, mainly in patients with a neoplastic disease (106).
Pulmonary involvement is described in 90% of the cases, but CNS or disseminated
manifestations may predominate (107). The isolation ofAspergillusfrom any SOT recipient
sample is always a warning clue. Although the lung is the primary site of infection, other
presentations have also been described (surgical wound, primary cutaneous infection,
infection of a biloma, endocarditis, endophthalmitis, etc.). Voriconazole is the mainstay of
therapy; although combined therapy may be indicated in especially severe cases (108).
Scedosporiumspp. are increasingly recognized as significant pathogens, particularly in
immunocompromised hosts. These fungi now account for*25% of all non-Aspergillusmould
infections in organ transplant recipients (109). Scedosporium spp. are generally resistant
to amphotericin B.S. prolificansin particular is also resistant to most currently available
antifungal agents. We found that 46% ofScedosporiuminfections in organ transplant recipients
were disseminated, and patients may occasionally present with shock and sepsis-like
syndrome (110). Fungemia is especially frequent whenS. prolificansis involved. Overall,
mortality rate forScedosporiuminfections in transplant recipients in our study was 58%. When
adjusted for disseminated infection, voriconazole as compared with amphotericin B was
associated with a lower mortality rate that approached statistical significance (p¼0.06).
P. jiroveci(formerP. carinii) is now rarely seen in SOT receiving prophylaxis. Before
prophylaxis, incidence was around 5%, although it has been described to reach up to 80% in
lung transplant recipients. PCP was diagnosed a median of 75 days after transplant (range,
37–781 days). Clinical presentation was acute (less than 48 hours) with fever (89%), shortness
of breath (84%), dry cough (74%), and hypoxia (63%). CMV was also isolated from lung or
blood in 74% of patients. Chest X ray usually showed interstitial pneumonia (84%). Some
patients required ventilatory support. Mortality was 26%. Older age was the only significant
poor prognostic factor (61 vs. 49 years;p<0.03) (111). Week-end prophylaxis (1 double-
strength tablet, 160/800 mg, every 12 hours on Saturdays and Sundays) has shown
practically universal efficacy, also eliminating the risk forListeriainfections and most cases of
Nocardiainfections (95,112).
C. neoformansaffects the lung in 55% of SOTs with cryptococcosis (113). However, the
disease is uncommon and appears a median of 24 months after transplantation (1 month to
17 years). An immune reconstitution syndrome-like entity may occur in organ transplant
recipients withC. neoformansinfection. This entity may be interpreted as failure of therapy.
Immunomodulatory agents may have a role as adjunctive therapy in such cases (114).
AlthoughCandidais frequently recovered from the lower respiratory tract (LRT) of
ventilated patients,Candidapneumonia is exceedingly rare (115). It has been reported in lung
transplant recipients and the diagnosis requires histological confirmation, since the recovery of
Candidamay represent colonization. In these patients, infection withCandidamay be associated
with very severe complications such as the necrosis of bronchial anastomoses (116–119).
Virus.CMV was the most common organism infecting the lungs in solid transplant
recipients, but the incidence has significantly decreased with the widespread use of
prophylaxis. CMV may be the sole causative agent of pneumonia after SOT or appear as a
copathogen when other microorganisms are isolated (73). CMV pneumonitis commonly
adopts a diffuse interstitial radiological appearance, but focal and even nodular infiltrates are
described in up to one-third of patients. CMV may cause severe pneumonia with ARDS
requiring ICU admission. In a recent study, in KT recipients, including 21 patients in this
situation, it was found that among 13 surviving patients, the numbers of CD4+ and CD8+ T
cells and their ratio increased as the patients recovered. In eight nonsurviving patients, the
numbers of CD4+ and CD8+ T cells and their ratio was similar to day 0. The authors conclude
that the variations of CD4+ and CD8+ T lymphocytes and their ratio are useful indicators of
the severity of disease and the outcome of patients with CMV infections accompanying ARDS
after renal transplantation. Nevertheless, it may be helpful to evaluate the efficiency of
ongoing treatment methods in these patients (120). Herpes simplex (121,122) and Varicella
zoster virus (VZV) may also cause pneumonia in the transplant population. HHV-6 has been
Infections in Organ Transplants in Critical Care 395