Risk factors for fluconazole resistance in patients with Candida glabrata bloodstream infection: potential impact of control group selection on characterizing the association between previous fluconazole use and fluconazole resistance

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Cross-resistance between voriconazole and fluconazole for non-albicans Candida infection: a case-case-control study

Cross-resistance (CR) between voriconazole and fluconazole for non-albicans Candida (NAC) species is not uncommon, but little is known about the risk factors and clinical consequences associated with this resistance phenotype. A case-case-control study was performed at a university-affiliated hospital in China between November 2012 and April 2016. The two case groups respectively comprised patients with a mono-resistance (MR) NAC infection (fluconazole or voriconazole resistance) and patients with a CR NAC infection (fluconazole and voriconazole resistance). Patients with a no-resistance (NR) NAC infection were included as the control group. Models were adjusted for demographic and clinical risk factors, and the risk of resistance associated with exposure to specific antibiotics or non-antibiotics were assessed. Of 259 episodes, 33 (12.7%) and 27 (10.4%) were identified as MR and CR NAC infections, respectively. The broad use of azoles was strongly associated with the emergence of MR and CR NAC infections (adjusted odds ratio [95% confidence interval] = 2.69 [1.10-6.58] and 2.53 [1.02-6.28], respectively). The time at risk (1.02 [1.00-1.03]) with 12 days as a breakpoint was also an independent risk factor for CR NAC infection. The number of species associated with a high minimum inhibitory concentration (≥128 μg/mL) of fluconazole was higher for CR NAC infections than for MR NAC infections. Different resistance phenotypes (CR vs. MR vs. NR) were associated with all-cause mortality rates. These findings indicate a worrisome propensity of CR NAC infections and emphasize the need for strict antifungal stewardship.

Epidemiology, species distribution, clinical characteristics and mortality of candidaemia in a tertiary care university hospital in Turkey, 2007-2014

Candidaemia still continues to be a serious medical concern and the epidemiology of candidaemia varies according to geographical areas. We aim to determine the incidence, local epidemiology, Candida species distribution and crude mortality rates of candidaemia. We retrospectively evaluated candidaemia episodes in between January 2007 and August 2014. We compared demographic, clinical, microbiological findings and mortality rates of episodes caused by Candida albicans and non-albicans Candida species. Overall the candidaemia incidences were 1.23 episodes/1000 admissions. A significant negative slope among candidaemia episodes and years was determined. Overall C. albicans (54.6%) was the most common species followed by Candida glabrata, Candida tropicalis and Candida parapsilosis respectively. Preinfection hospital stay and length of hospital stay were statistically longer in patients with non-albicans Candida candidaemia than in patients with C. albicans candidaemia. The source of candidaemia was unknown in 52.5% of all episodes. Central venous catheters among non-albicans Candida candidaemia episodes and urinary system among C. albicans candidaemia episodes were common source of candidaemia compared to each other. Previous antifungal therapy preceding candidaemia and concomitant bacteraemia were significantly associated with non-albicans Candida candidaemia. Continuous local surveillance will preserve its pivotal importance in formulating empirical antifungal therapy and improving management of candidaemia.

The Correlation Between Biofilm Production and Catheter-Related Bloodstream Infections Sustained by Candida. A Case Control Study

Biofilm forming capacity of yeasts colonizing the intravenous devices is considered a key factor involved in the pathogenesis of Candida catheter-related bloodstream infections (CCRBSI). The biofilm production of strains of Candida spp. isolated both from the CVC and from the blood of patients with CCRBSI was compared to that of strains isolated from patients not having CCRBSI. Results, expressed in terms of Biofilm Index (BI), revealed that biofilm-producing strains were isolated in the CCRBSI group with a frequency significantly higher than in the non-CCRBSI group (χ² = 4.25, p = 0.03). The species more frequently cultured was C. parapsilosis complex (including C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis). When this species was isolated from the CVC tip cultures of the CCRBSI group it showed BIs significantly (p = 0.05) higher than those found in the non-CCRBSI group. All the strains of C. tropicalis isolated from the CCRBSI group produced biofilm. Instead most of the isolates of C. glabrata were non-producers. The cumulative BI of non-albicans Candida strains isolated from CCRBSI patients was significantly higher than that of non-albicans strains cultured from patients non-CCRBSI (χ² = 6.91; p = 0.008). C. albicans was a biofilm producer both in the CCRBSI and in the non-CCRBSI group. When isolated from the blood it showed enhanced biofilm production in the CCRBSI group only, while when colonizing the CVC it displayed high BIs both in the CCRBSI group and in non-CCRBSI group. Our data seem to indicate that the biofilm production capacity should be considered in the clinical management of CCRBSI.

Is Fluconazole or an Echinocandin the Agent of Choice for Candidemia

OBJECTIVE

Candidemia is among the most common nosocomial bloodstream infections and is associated with high mortality, increased length of hospital stay, and significant economic burden. The introduction of the echinocandins in the 2000s has expanded the armamentarium against Candida spp and provides therapeutic options that are effective, safe, and tolerable. Although the Infectious Diseases Society of America favors echinocandins as treatment for candidemia in selected settings (at least as initial therapy), there remain divergent opinions about whether an echinocandin or fluconazole is the preferred agent for candidemia, and clinical practice guidelines are in flux. In this review, the currently available laboratory and clinical data are summarized and critically evaluated.

DATA SOURCES

A MEDLINE search of the English language literature was performed using the search terms echinocandin, fluconazole, and candidemia. References of review articles and guidelines were also screened for inclusion.

STUDY SELECTION AND DATA EXTRACTION

Studies whose primary goal was to compare echinocandins with fluconazole were evaluated as well as studies that differentiated pharmacological and pharmacokinetic properties between agents.

DATA SYNTHESIS

It is clear that echinocandins and fluconazole each have roles in the management of candidemia. Specific recommendations are provided that will hopefully optimize outcomes in candidemia while incorporating stewardship concepts of cost-effectiveness and limiting the emergence of resistance.

CONCLUSIONS

Despite the advantages brought by the echinocandins and fluconazole, outcomes among patients with candidemia remain suboptimal. Improved treatment of candidemia may ultimately be achieved by optimizing the use of antifungal agents rather than the development of new drugs.

Active surveillance of candidemia in children from Latin America: a key requirement for improving disease outcome

BACKGROUND

Active surveillance is necessary for improving the management and outcomes of patients with candidemia. The aim of this study was to describe the epidemiologic and clinical features of candidemia in pediatric patients in Latin America.

METHOD

Prospective, multicenter, surveillance study of candidemia in a pediatric population from 23 hospitals in 8 Latin America countries between November 2008 and October 2010.

RESULTS

Three hundred and two cases of candidemia were reported with a median incidence of 0.81/1000 admissions. Eighty nine (29%) were neonates. The main risk factors were prematurity, intensive care unit (ICU) admission, parenteral nutrition, respiratory disease and mechanical ventilation in neonates and malignancy, neutropenia, neurological disease and previous use of corticosteroids in children. The main species isolated in neonates and children were Candida albicans (43.8% and 35.7%), Candida parapsilosis (27.0% and 26.3%) and Candida tropicalis (14.6% and 14.6%), respectively. The most frequent antifungal therapy used in neonates and children was deoxycholate-amphotericin-B (43.8% and 29.1%) and fluconazole (28.1% and 53.1%). Seventeen neonates (19.1%) and 20 children (9.4%) did not receive antifungal therapy. The 30-day survival rate was 60% in neonates and 72% in children (P = 0.02). Survival was significantly higher in treated than in nontreated neonates (72% vs. 24%; P < 0.001). A multivariate analysis showed that independent predictors for 30-day mortality in children were renal disease (odds ratio: 4.38, 95% confidence interval: 1.92-10.1, P < 0.001) and receipt of corticosteroids (odds ratio: 2.08, 95% confidence interval: 1.04-4.17, P = 0.04).

CONCLUSIONS

To our knowledge, this is the first prospective, multicenter surveillance study of candidemia in children in Latin America. This epidemiologic information may provide us with methods to improve preventive, diagnostic and therapeutic strategies in our continent.

Risk factors for infection or colonization with CTX-M extended-spectrum-β-lactamase-positive Escherichia coli

There has been a significant increase in the prevalence of Enterobacteriaceae that produce CTX-M-type extended-spectrum β-lactamases. The objective of this study was to evaluate risk factors for infection or colonization with CTX-M-positive Escherichia coli. A case-control study was conducted within a university system from 1 January 2007 to 31 December 2008. All patients with clinical cultures with E. coli demonstrating resistance to extended-spectrum cephalosporins were included. Case patients were designated as those with cultures positive for CTX-M-positive E. coli, and control patients were designated as those with non-CTX-M-producing E. coli. Multivariable logistic regression analyses were performed to evaluate risk factors for CTX-M-positive isolates. A total of 83 (56.8%) of a total of 146 patients had cultures with CTX-M-positive E. coli. On multivariable analyses, there was a significant association between infection or colonization with CTX-M-type β-lactamase-positive E. coli and receipt of piperacillin-tazobactam in the 30 days prior to the culture date (odds ratio [OR], 7.36; 95% confidence interval [CI], 1.61 to 33.8; P = 0.01) and a urinary culture source (OR, 0.36; 95% CI, 0.17 to 0.77; P = 0.008). The rates of resistance to fluoroquinolones were significantly higher in isolates from case patients than in isolates from control patients (90.4 and 50.8%, respectively; P < 0.001). We found that nonurinary sources of clinical cultures and the recent use of piperacillin-tazobactam conferred an increased risk of colonization or infection with CTX-M-positive E. coli. Future studies will need to focus on outcomes associated with infections due to CTX-M-positive E. coli, as well as infection control strategies to limit the spread of these increasingly common organisms.

Fluconazole exposure rather than clonal spreading is correlated with the emergence of Candida glabrata with cross-resistance to triazole antifungal agents

The emergence of antifungal resistance in Candida species has raised concern in recent years, especially resistance toward triazole. Several newer triazole antifungal agents have been introduced which have a broader spectrum for fungal infections, such as voriconazole. However, cross-resistance among triazoles is a major concern with regard to their clinical application. Antifungal susceptibility was performed using E-test for 166 clinical isolates (29 blood and 137 nonblood isolates) in 2003 and 2004. We applied pulsed-field gel electrophoresis for genotyping. Ninety isolates of C. albicans, 47 isolates of C. tropicalis, 27 isolates of C. glabrata, and two isolates of C. krusei were included. All isolates were susceptible to amphotericin B. Eleven (40.7%) of the 27 C. glabrata had intermediate resistance to caspofungin. Forty-seven (28.3%) of the 166 isolates were not susceptible to fluconazole, including two C. albicans, 16 C. tropicalis, 27 C. glabrata, and two C. krusei isolates. All except seven of the C. glabrata isolates were susceptible to voriconazole. All the triazole drugs had a positive correlation among their minimum inhibitory concentrations (MICs). Fluconazole MIC was a good predictor for susceptibility to voriconazole, as determined using a receiver operating characteristic curve. Furthermore, a high diversity of pulsotypes for the 27 clinical isolates of C. glabrata was observed. Previous fluconazole exposure within 3 months was associated with reduced triazole susceptibility for C. glabrata. We demonstrated a significant positive correlation of MIC values among the four tested triazole drugs. No amphotericin B and caspofungin resistant isolates were found in this study. The cross-resistance to triazole among C. glabrata isolates was associated with previous fluconazole exposure as opposed to clonal spreading. Selection pressure due to fluconazole use may play a major role in triazole cross-resistance.

Frequency of decreased susceptibility and resistance to echinocandins among fluconazole-resistant bloodstream isolates of Candida glabrata

The echinocandin class of antifungal agents is considered to be the first-line treatment of bloodstream infections (BSI) due to Candida glabrata. Recent reports of BSI due to strains of C. glabrata resistant to both fluconazole and the echinocandins are of concern and prompted us to review the experience of two large surveillance programs, the SENTRY Antimicrobial Surveillance Program for the years 2006 through 2010 and the Centers for Disease Control and Prevention population-based surveillance conducted in 2008 to 2010. The in vitro susceptibilities of 1,669 BSI isolates of C. glabrata to fluconazole, voriconazole, anidulafungin, caspofungin, and micafungin were determined by CLSI broth microdilution methods. Fluconazole MICs of ≥64 μg/ml were considered resistant. Strains for which anidulafungin and caspofungin MICs were ≥0.5 μg/ml and for which micafungin MICs were ≥0.25 μg/ml were considered resistant. A total of 162 isolates (9.7%) were resistant to fluconazole, of which 98.8% were nonsusceptible to voriconazole (MIC > 0.5 μg/ml) and 9.3%, 9.3%, and 8.0% were resistant to anidulafungin, caspofungin, and micafungin, respectively. There were 18 fluconazole-resistant isolates that were resistant to one or more of the echinocandins (11.1% of all fluconazole-resistant isolates), all of which contained an acquired mutation in fks1 or fks2. By comparison, there were no echinocandin-resistant strains detected among 110 fluconazole-resistant isolates of C. glabrata tested in 2001 to 2004. These data document the broad emergence of coresistance over time to both azoles and echinocandins in clinical isolates of C. glabrata.

Effect of pH on in vitro susceptibility of Candida glabrata and Candida albicans to 11 antifungal agents and implications for clinical use

The treatment of vulvovaginal candidiasis (VVC) due to Candida glabrata is challenging, with limited therapeutic options. Unexplained disappointing clinical efficacy has been reported with systemic and topical azole antifungal agents in spite of in vitro susceptibility. Given that the vaginal pH of patients with VVC is unchanged at 4 to 4.5, we studied the effect of pH on the in vitro activity of 11 antifungal agents against 40 C. glabrata isolates and compared activity against 15 fluconazole-sensitive and 10 reduced-fluconazole-susceptibility C. albicans strains. In vitro susceptibility to flucytosine, fluconazole, voriconazole, posaconazole, itraconazole, ketoconazole, clotrimazole, miconazole, ciclopirox olamine, amphotericin B, and caspofungin was determined using the CLSI method for yeast susceptibility testing. Test media were buffered to pHs of 7, 6, 5, and 4. Under conditions of reduced pH, C. glabrata isolates remained susceptible to caspofungin and flucytosine; however, there was a dramatic increase in the MIC(90) for amphotericin B and every azole drug tested. Although susceptible to other azole drugs tested at pH 7, C. albicans strains with reduced fluconazole susceptibility also demonstrated reduced susceptibility to amphotericin B and all azoles at pH 4. In contrast, fluconazole-sensitive C. albicans isolates remained susceptible at low pH to azoles, in keeping with clinical observations. In selecting agents for treatment of recurrent C. glabrata vaginitis, clinicians should recognize the limitations of in vitro susceptibility testing utilizing pH 7.0.

Epidemiology of invasive candidiasis

PURPOSE OF REVIEW

This review covers candidaemia in numbers, susceptibility issues, host groups, risk factors and outcome.

RECENT FINDINGS

The incidence of candidaemia has increased over the last decades. Candida glabrata is particularly common in the northern hemisphere and with increasing age whilst the opposite is true for C. parapsilosis, C. glabrata, C. krusei and a number of emerging species are not fully susceptible to azoles. C. parapsilosis and C. guilliermondii are not fully susceptible to echinocandins. Increasing rates of C. parapsilosis have been observed at centres with a high use of echinocandins, and outcome for this species is not superior comparing echinocandins with fluconazole. Acquired azole resistance has recently been described in as many as a third of 19% resistant isolates and echinocandin resistance has emerged and been detected as early as day 12 of echinocandin therapy. ICU stay and abdominal surgery are among the most important risk factors. Outcome is dependent on species involved, timing, dosing and choice of therapy and management of the primary focus of infection. However, host factors are dominating predictors of mortality in recent studies of ICU candidiasis.

SUMMARY

The changing epidemiology highlights the need for close monitoring of local incidence, species distribution and susceptibility in order to optimize therapy and outcome.