Invasive Candida duobushaemulonii infections in Panama hospitals: importance of laboratory surveillance and accurate species identification

Objectives: Candida duobushaemulonii, like Candida auris, is an emerging multidrug-resistant yeast. This report describes 14 cases of Candida duobushaemulonii (10 invasive infections), in Panama, Central America, during 2016–2017.

Methods: Given the emergence of C. auris, the Panamanian Ministry of Health implemented laboratory surveillance for C. auris in October 2016. Suspected C. auris isolates (isolates identified as Candida haemulonii, Candida famata, or Candida spp. by VITEK 2®, which was available in laboratories within Panama’s national laboratory network) were forwarded to the national reference laboratory for further identification by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and antifungal susceptibility testing (AFST).

Results: During November 2016–May 2017, 36 isolates from 31 patients were obtained as part of C. auris surveillance; all were initially identified as C. haemulonii. Seventeen (47%) were confirmed as C. duobushaemulonii, eight (22%) as C. haemulonii, five (14%) as C. auris, and six (17%) as other Candida species. C. duobushaemulonii isolates (n=17) were obtained from 14 patients who were hospitalized at six medical institutions in four geographical regions of Panama. Of the 14 cases of C. duobushaemulonii infection or colonization, 10 involved bloodstream infection (BSIs). Two patients with BSIs had multiple positive blood cultures. In the remaining four cases, C. duobushaemulonii was recovered from endotracheal secretion (n=2), surgical mesh (n=1), and exposed bone (n=1). Three cases, all BSIs, were in children. AFST revealed elevated minimum inhibitory concentrations for fluconazole, voriconazole, and amphotericin B. No resistance to caspofungin or micafungin was observed. 

Conclusion: In recent years, we have seen the emergence of invasive infections caused by highly drug-resistant Candida such as C. auris and now C. duobushaemulonii. These species are often misidentified using commonly used yeast identification methods, and much remains to be understood about their transmission, pathogenesis, and reservoirs. Expanded laboratory surveillance is an important step in the detection and control of such emerging pathogens.