Evaluation of the possible influence of trailing and paradoxical effects on the clinical outcome of patients with candidemia.
OBJECTIVE
Paradoxical growth (PG) and trailing effect (TE) are frequently observed during antifungal susceptibility testing (AFST). These two phenomena interfere with the determination of the minimal inhibitory concentration (MIC). The aim of this study was to assess the clinical impact of TE and PG.


METHODS
We analysed the frequency of TE and PG of 690 Candida isolates collected from a population-based study performed in Spain (CANDIPOP) and correlated the results with clinical outcome of the patients.


RESULTS
Around 70% (484/690) of the isolates exhibited TE to azoles. Candida tropicalis showed the highest presence of TE (39/53 isolates exhibited residual growth >25% of control). No TE was seen in most of the isolates from the psilosis complex. PG was mainly associated with echinocandins. In patients treated with fluconazole within the first 48 hours after blood sampling (n = 221), the presence of TE to azoles tended to be associated with lower 30-day mortality (odds ratio (OR) 0.55, 95% confidence interval (CI) 0.25-1.00) but not with clinical failure (OR 0.85, 95% CI 0.45-1.54). In the subgroup of 117 patients treated with echinocandins, the presence of PG was not associated with patient's response to antifungal treatment (OR for 30-day mortality 1.63, 95% CI 0.76-4.03; OR for clinical failure 1.17, 95% CI 0.53-2.70).


CONCLUSIONS
TE or PG are widely expressed among Candida spp., although they do not seem to influence clinical outcome.
Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain.
C
C
Rueda
Infectious Diseases Department, Hospital Universitari Vall d'Hebron, Medicine Department, Autonomous University of Barcelona, Barcelona, Spain.
M
M
Puig-Asensio
Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
J
J
Guinea
Infectious Diseases Department, Hospital Universitari Vall d'Hebron, Medicine Department, Autonomous University of Barcelona, Barcelona, Spain.
B
B
Almirante
Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain.
M
M
Cuenca-Estrella
Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain. Electronic address: ozaragoza@isciii.es.
O
O
Zaragoza
D000375:Aging; D000935:Antifungal Agents / Q000627:therapeutic use*; D002175:Candida / Q000145:classification* / Q000187:drug effects; D058387:Candidemia / Q000188:drug therapy* / Q000382:microbiology; D015331:Cohort Studies; D025141:Drug Resistance, Fungal; D006801:Humans; D016017:Odds Ratio; D013045:Species Specificity; D016896:Treatment Outcome
D000935:Antifungal Agents
Azoles; Candida; Echinocandins; Paradoxical growth; Trailing effect