Prevalence, Distribution, and Antifungal Susceptibility Profiles of Candida parapsilosis , C. orthopsilosis , and C. metapsilosis in a Tertiary Care Hospital

Abstract

Candida parapsilosis, an emergent agent of nosocomial infections, was previously made up of a complex of three genetically distinct groups (groups I, II, and III). Recently, the C. parapsilosis groups have been renamed as distinct species: C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis. In Portugal, no data pertaining to the distribution and antifungal susceptibility of these Candida species are yet available. In the present report, we describe the incidence and distribution of C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis among 175 clinical and environmental isolates previously identified by conventional methods as C. parapsilosis. We also evaluated the in vitro susceptibilities of the isolates to fluconazole, voriconazole, posaconazole, amphotericin B, and two echinocandins, caspofungin and anidulafungin. Of the 175 isolates tested, 160 (91.4%) were identified as C. parapsilosis sensu stricto, 4 (2.3%) were identified as C. orthopsilosis, and 5 (2.9%) were identified as C. metapsilosis. Six isolates corresponded to species other than the C. parapsilosis group. Interestingly, all isolates from blood cultures corresponded to C. parapsilosis sensu stricto. Evaluation of the antifungal susceptibility profile showed that only nine (5.6%) C. parapsilosis sensu stricto strains were susceptible-dose dependent or resistant to fluconazole, and a single strain displayed a multiazoleresistant phenotype; two (1.3%) C. parapsilosis sensu stricto strains were amphotericin B resistant. All C. orthopsilosis and C. metapsilosis isolates were susceptible to azoles and amphotericin B. A high number of strains were nonsusceptible to the echinocandins (caspofungin and anidulafungin).

Prevalence and antifungal susceptibility of Candida parapsilosis complex isolates collected from oral cavities of HIV-infected individuals

“…One sample, isolated from the throat, was identified as C. metapsilosis, whereas no C. orthopsilosis was detected. Silva et al (2009) studied 169 samples isolated from nine different anatomical sites of patients hospitalized in a tertiary care hospital in Portugal and found that C. parapsilosis sensu stricto was identified in 160 (94.7 %) samples, C. orthopsilosis in five (2.9 %) samples and C. metapsilosis in four (2.4 %) samples. Of the 69 mucosal samples isolated in the study by Silva et al (2009), 94.2 % corresponded to C. parapsilosis sensu stricto and 5.8 % to C. metapsilosis.…”

“…In our study, there were no marked differences in MICs between strains. Therefore, the resistance of C. parapsilosis sensu stricto to VRC and CASPO that was observed by Silva et al (2009) may be associated with a geographical or regional pattern. The sensitivity of the different species that constitute the C. parapsilosis complex to antifungal compounds needs to be elucidated to better understand geographical differences in the prevalence of these different species and the impact this has on treatment, especially for immunosuppressed patients.…”

“…It is of note that Silva et al (2009) reported two cases out of 160 isolates of C. parapsilosis sensu stricto that developed resistance to AMB and Lockhart et al (2008) reported that the MICs of AMB for C. metapsilosis were lower than those of C. parapsilosis sensu stricto. C. metapsilosis isolates displayed a tendency to have diminished susceptibility to FLC, compared with C. parapsilosis sensu stricto with median MICs of 1.5 and 0.5 mg ml 21 , respectively, which are agreement with those observed by van Asbeck et al (1995) and Hensgens et al (2009), showing all isolates to be susceptible to this antifungal compound.…”

“…Although the C. parapsilosis complex has been recognized as comprising distinct species, little is known about the transmission and infectivity of the two more rare species present within the complex, C. orthopsilosis and C. metapsilosis, while C. parapsilosis has now been recognized as a major human fungal pathogen, ranking as the second or third most frequently occurring cause of bloodstream infection in Europe, Canada and Latin America (Almirante et al, 2006;Pemán et al, 2005;Pfaller et al, 2008). Data on the frequency of isolation of C. orthopsilosis and C. metapsilosis have just started to be released (Odds et al, 2007;Tavanti et al, 2007;Kocsubé et al, 2007;Gomez-Lopez et al, 2008;Lockhart et al, 2008;Hensgens et al, 2009;Silva et al, 2009;Gonçalves et al, 2010;Ghannoum et al, 2010;Bonfietti et al, 2012). These retrospective epidemiological studies have been undertaken to screen for C. orthopsilosis and C. metapsilosis among isolates previously identified as C. parapsilosis, showing that a small proportion of isolates actually belong to the species C. orthopsilosis or C. metapsilosis, with significant geographical variation.…”

“…Members of the C. parapsilosis complex are normally susceptible to most antifungal compounds but previous studies reported decreased responsiveness to fluconazole (FLC) and caspofungin (CASPO) (Sarvikivi et al, 2005;Legout et al, 2006;Lockhart et al, 2008;van Asbeck et al, 2008;Gonçalves et al, 2010;Silva et al, 2009). It was also suggested that C. orthopsilosis and C. metapsilosis might be more susceptible to amphotericin B (AMB) and echinocandins than C. parapsilosis sensu stricto (Gomez-Lopez et al, 2008;van Asbeck et al, 2008;Garcia-Effron et al, 2008) and that these differences in antifungal susceptibility could affect choice of therapy.…”