Discriminating invasive fungal infection from colonization

Fungal infections in burns: a comprehensive review

Burn wound infections remain the most important factor limiting survival in burn intensive care units. Large wound surface, impaired immune systems, and broad-spectrum antibiotic therapy contribute to the growth of opportunistic fungal species. Faced with challenging fluid resuscitation, wound excision and cardiopulmonary stabilization, mycosis in burns are likely to be underestimated. Diagnostic performance can sometimes be delayed because clinical signs are unspecific and differentiation between colonization and infection is difficult. Therapeutic measures range from infection prophylaxis over treatment with antifungal agents towards radical amputation of infected limbs. New methods of early and reliable detection of fungal organisms, as well as the use of novel antifungal substances, are promising but require wider establishment to confirm the beneficial effects in burn patients. This review aims to highlight the main important aspects of fungal infections in burns including incidence, infection control, diagnostic and therapeutic approaches, prognosis and outcomes.

In vitro antifungal susceptibilities of Candida isolates from patients with invasive candidiasis in Kuala Lumpur Hospital, Malaysia

The in vitro antifungal susceptibilities of 159 clinical isolates of Candida species from patients with invasive candidiasis in Kuala Lumpur Hospital, Malaysia, were determined against amphotericin B, fluconazole, voriconazole, itraconazole and caspofungin. The most common species were Candida albicans (71 isolates), Candida parapsilosis (42 isolates), Candida tropicalis (27 isolates) and Candida glabrata (12 isolates). The susceptibility tests were carried out using an E-test. The MIC breakpoints were based on Clinical Laboratory Standards Institute criteria. Amphotericin B and voriconazole showed the best activities against all the isolates tested, with MIC(90) values of ≤1 µg ml(-1) for all major species. Only one Candida lusitaniae isolate was resistant to amphotericin B, and all the isolates were susceptible to voriconazole. In total, six isolates were resistant to fluconazole, comprising two isolates of C. albicans, two of C. parapsilosis, one C. tropicalis and one C. glabrata, and all of these isolates showed cross-resistance to itraconazole. The MIC(90) of itraconazole was highest for C. glabrata and C. parapsilosis. Caspofungin was active against most of the isolates except for five isolates of C. parapsilosis. The MIC(90) of caspofungin against C. parapsilosis was 3 µg ml(-1). In conclusion, amphotericin B remains the most active antifungal agent against most Candida species except for C. lusitaniae. Voriconazole is the best alternative for fluconazole- or itraconizole-resistant isolates. Although five of the C. parapsilosis isolates showed in vitro resistance to caspofungin, more clinical correlation studies need to be carried out to confirm the significance of these findings. Currently, despite the increase in usage of antifungals in our hospitals, especially in the management of febrile neutropenia patients, the antifungal-resistance problem among clinically important Candida isolates in Kuala Lumpur Hospital is not yet worrying. However, continued antifungal-susceptibility surveillance needs to be conducted to monitor the antifungal-susceptibility trends of Candida species and other opportunistic fungal pathogens.

Is Candida really a threat in the ICU?

PURPOSE OF REVIEW

The epidemiological and clinical relevance of Candida in the ICU is reviewed. Three issues were appraised. First is the prevalence of Candida. Second is the relevance of nonblood cultures positive for Candida and multisite colonization. Third is the importance of invasive candidiasis in terms of mortality.

RECENT FINDINGS

The diagnosis of invasive candidiasis remains problematic in nonblood cultures. Consequently, the true prevalence of invasive candidiasis is difficult to assess. Another result of the complicated diagnosis is the risk for delayed antifungal therapy in case of systemic Candida infection. Therefore, pre-emptive therapy has become increasingly popular in high-risk patients.

SUMMARY

Candida spp. cause a minority of nosocomial bloodstream infections ( approximately 4-9%). Yet, delayed initiation of appropriate antifungal therapy results in significant attributable mortality. Given the inability to efficiently discriminate colonization from invasive candidiasis, this is a problematic issue. The presence of Candida in tracheal aspirates, urine cultures or wound swabs frequently reflects colonization. Yet, multisite colonization frequently precedes systemic invasion. As such, multisite Candida colonization is a crucial element in the decision to start pre-emptive therapy. However, the predictive value of multisite colonization in the absence of an overt risk profile for invasive candidiasis appears to be low.