Evolution of antifungal susceptibility among Candida species isolates recovered from human immunodeficiency virus-infected women receiving fluconazole prophylaxis

The Antibiofilm Role of Biotics Family in Vaginal Fungal Infections

“Unity in strength” is a notion that can be exploited to characterize biofilms as they bestow microbes with protection to live freely, escalate their virulence, confer high resistance to therapeutic agents, and provide active grounds for the production of biofilms after dispersal. Naturally, fungal biofilms are inherently resistant to many conventional antifungals, possibly owing to virulence factors as their ammunitions that persistently express amid planktonic transition to matured biofilm state. These ammunitions include the ability to form polymicrobial biofilms, emergence of persister cells post-antifungal treatment and acquisition of resistance genes. One of the major disorders affecting vaginal health is vulvovaginal candidiasis (VVC) and its reoccurrence is termed recurrent VVC (RVVC). It is caused by the Candida species which include Candida albicans and Candida glabrata. The aforementioned Candida species, notably C. albicans is a biofilm producing pathogen and habitually forms part of the vaginal microbiota of healthy women. Latest research has implicated the role of fungal biofilms in VVC, particularly in the setting of treatment failure and RVVC. Consequently, a plethora of studies have advocated the utilization of probiotics in addressing these infections. Specifically, the excreted or released compounds of probiotics which are also known as postbiotics are being actively researched with vast potential to be used as therapeutic options for the treatment and prevention of VVC and RVVC. These potential sources of postbiotics are harnessed due to their proven antifungal and antibiofilm. Hence, this review discusses the role of Candida biofilm formation in VVC and RVVC. In addition, we discuss the application of pro-, pre-, post-, and synbiotics either individually or in combined regimen to counteract the abovementioned problems. A clear understanding of the role of biofilms in VVC and RVVC will provide proper footing for further research in devising novel remedies for prevention and treatment of vaginal fungal infections.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

A High Rate of Recurrent Vulvovaginal Candidiasis and Therapeutic Failure of Azole Derivatives Among Iranian Women

Recurrent vulvovaginal candidiasis (RVVC) is one of the most prevalent fungal infections in humans, especially in developing countries; however, it is underestimated and regarded as an easy-to-treat condition. RVVC may be caused by dysbiosis of the microbiome and other host-, pathogen-, and antifungal drug-related factors. Although multiple studies on host-related factors affecting the outcome have been conducted, such studies on Candida-derived factors and their association with RVVC are lacking. Thus, fluconazole-tolerant (FLZT) isolates may cause fluconazole therapeutic failure (FTF), but this concept has not been assessed in the context of Candida-associated vaginitis. Iran is among the countries with the highest burden of RVVC; however, comprehensive studies detailing the clinical and microbiological features of this complication are scarce. Therefore, we conducted a 1-year prospective study with the aim to determine the RVVC burden among women referred to a gynecology hospital in Tehran, the association of the previous exposure to clotrimazole and fluconazole with the emergence of FLZT and fluconazole-resistant (FLZR) Candida isolates, and the relevance of these phenotypes to FTF. The results indicated that about 53% of the patients (43/81) experienced RVVC. Candida albicans and C. glabrata constituted approximately 90% of the yeast isolates (72 patients). Except for one FLZT C. tropicalis isolate, FLZR and FLZT phenotypes were detected exclusively in patients with RVVC; among them, 27.9% (12/43) harbored FLZR strains. C. albicans constituted 81.2% of FLZR (13/16) and 100% of the FLZT (13/13) isolates, respectively, and both phenotypes were likely responsible for FTF, which was also observed among patients with RVVC infected with fluconazole-susceptible isolates. Thus, FTF could be due to host-, drug-, and pathogen-related characteristics. Our study indicates that FLZT and FLZR isolates may arise following the exposure to over-the-counter (OTC) topical azole (clotrimazole) and that both phenotypes can cause FTF. Therefore, the widespread use of OTC azoles can influence fluconazole therapeutic success, highlighting the necessity of controlling the use of weak topical antifungals among Iranian women.

Primary antifungal prophylaxis for cryptococcal disease in HIV-positive people

BACKGROUND

Cryptococcal disease remains one of the main causes of death in HIV-positive people who have low cluster of differentiation 4 (CD4) cell counts. Currently, the World Health Organization (WHO) recommends screening HIV-positive people with low CD4 counts for cryptococcal antigenaemia (CrAg), and treating those who are CrAg-positive. This Cochrane Review examined the effects of an approach where those with low CD4 counts received regular prophylactic antifungals, such as fluconazole.

OBJECTIVES

To assess the efficacy and safety of antifungal drugs for the primary prevention of cryptococcal disease in adults and children who are HIV-positive.

SEARCH METHODS

We searched the CENTRAL, MEDLINE PubMed, Embase OVID, CINAHL EBSCOHost, WHO International Clinical Trials Registry Platform (WHO ICTRP), ClinicalTrials.gov, conference proceedings for the International AIDS Society (IAS) and Conference on Retroviruses and Opportunistic Infections (CROI), and reference lists of relevant articles up to 31 August 2017.

SELECTION CRITERIA

Randomized controlled trials of adults and children, who are HIV-positive with low CD4 counts, without a current or prior diagnosis of cryptococcal disease that compared any antifungal drug taken as primary prophylaxis to placebo or standard care.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and risk of bias, and extracted and analysed data. The primary outcome was all-cause mortality. We summarized all outcomes using risk ratios (RR) with 95% confidence intervals (CI). Where appropriate, we pooled data in meta-analyses. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Nine trials, enrolling 5426 participants, met the inclusion criteria of this review. Six trials administered fluconazole, while three trials administered itraconazole.Antifungal prophylaxis may make little or no difference to all-cause mortality (RR 1.07, 95% CI 0.80 to 1.43; 6 trials, 3220 participants; low-certainty evidence). For cryptococcal specific outcomes, prophylaxis probably reduces the risk of developing cryptococcal disease (RR 0.29, 95% CI 0.17 to 0.49; 7 trials, 5000 participants; moderate-certainty evidence), and probably reduces deaths due to cryptococcal disease (RR 0.29, 95% CI 0.11 to 0.72; 5 trials, 3813 participants; moderate-certainty evidence). Fluconazole prophylaxis may make no clear difference to the risk of developing clinically resistant Candida disease (RR 0.93, 95% CI 0.56 to 1.56; 3 trials, 1198 participants; low-certainty evidence); however, there may be an increased detection of fluconazole-resistant Candida isolates from surveillance cultures (RR 1.25, 95% CI 1.00 to 1.55; 3 trials, 539 participants; low-certainty evidence). Antifungal prophylaxis was generally well-tolerated with probably no clear difference in the risk of discontinuation of antifungal prophylaxis compared with placebo (RR 1.01, 95% CI 0.91 to 1.13; 4 trials, 2317 participants; moderate-certainty evidence). Antifungal prophylaxis may also make no difference to the risk of having any adverse event (RR 1.07, 95% CI 0.88 to 1.30; 4 trials, 2317 participants; low-certainty evidence), or a serious adverse event (RR 1.08, 95% CI 0.83 to 1.41; 4 trials, 888 participants; low-certainty evidence) when compared to placebo or standard care.

AUTHORS' CONCLUSIONS

Antifungal prophylaxis reduced the risk of developing and dying from cryptococcal disease. Therefore, where CrAG screening is not available, antifungal prophylaxis may be used in patients with low CD4 counts at diagnosis and who are at risk of developing cryptococcal disease.

Clinico-mycological analysis and antifungal resistance pattern in human immunodeficiency virus-associated candidiasis: An Indian perspective

Objectives:

Candidiasis is a common human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome-associated opportunistic mycoses. The present study ascertained the species spectrum of Candida strains recovered from different clinical samples from symptomatic HIV-positive individuals and determined the antifungal susceptibility profile of the isolates.

Materials and Methods:

A variety of specimens were collected from 234 symptomatic HIV seropositive individuals depending on their clinical manifestations and subjected to direct microscopic examination. Blood samples were inoculated in biphasic blood culture medium and all other specimens on Sabouraud dextrose agar with chloramphenicol and incubated at 35°C–37°C. Species identification of the recovered Candida isolates was attempted on the basis of germ tube production, micromorphology on corn meal agar, color and morphology on HiCrome Candida Differential agar, and carbohydrate fermentation and assimilation tests. Susceptibility testing of the isolates was performed employing the VITEK 2 system.

Results:

A total of 167 Candida isolates were obtained; Candida albicans (136), Candida tropicalis (13), Candida krusei (8), Candida parapsilosis (5), Candida glabrata (4), and Candida kefyr (1). Fluconazole resistance was more frequent among nonalbicans species, and significantly higher 5-fluorocytosine resistance compared to C. albicans was also observed. Eight Candida strains (six C. krusei, one C. kefyr, and one C. albicans) were multidrug resistant.

Conclusion:

Although C. albicans continues to be the leading etiological agent of candidiasis, the incidence of nonalbicans species among HIV-positive Indian individuals is rising. Antifungal resistance was higher among nonalbicans Candida species. Another issue of therapeutic concern is the possible emergence of multidrug-resistant Candida strains among these patients.

Practice Bulletin No. 167: Gynecologic Care for Women and Adolescents With Human Immunodeficiency Virus

In the United States in 2013, there were an estimated 226,000 women and adolescents living with human immunodeficiency virus (HIV) infection (1). Women with HIV are living longer, healthier lives, so the need for routine and problem-focused gynecologic care has increased. The purpose of this document is to educate clinicians about basic health screening and care, family planning, prepregnancy care, and managing common gynecologic problems for women and adolescents who are infected with HIV. For information on screening guidelines, refer to the American College of Obstetricians and Gynecologists' Committee Opinion No. 596, Routine Human Immunodeficiency Virus Screening (2).

Development of a real-time PCR assay for the direct detection of Candida species causing Vulvovaginal candidiasis

Identification of Candida species by traditional methods can be time-consuming and have limited analytical sensitivity. We developed a multiplex real-time PCR assay for detection and differentiation of Candida species causing vulvovaginal candidiasis (VVC). Overall, this PCR assay is a powerful diagnostic tool offering superior accuracy, sensitivity, and specificity.

Future therapies targeted towards eliminating Candida biofilms and associated infections

INTRODUCTION

Candida species are common human commensals and cause either superficial or invasive opportunistic infections. The biofilm form of candida as opposed to its suspended, planktonic form, is predominantly associated with these infections. Alternative or adjunctive therapies are urgently needed to manage Candida infections as the currently available short arsenal of antifungal drugs has been compromised due to their systemic toxicity, cross-reactivity with other drugs, and above all, by the emergence of drug-resistant Candida species due to irrational drug use. Areas covered: Combination anti-Candida therapies, antifungal lock therapy, denture cleansers, and mouth rinses have all been proposed as alternatives for disrupting candidal biofilms on different substrates. Other suggested approaches for the management of candidiasis include the use of natural compounds, such as probiotics, plants extracts and oils, antifungal quorum sensing molecules, anti-Candida antibodies and vaccines, cytokine therapy, transfer of primed immune cells, photodynamic therapy, and nanoparticles. Expert commentary: The sparsity of currently available antifungals and the plethora of proposed anti-candidal therapies is a distinct indication of the urgent necessity to develop efficacious therapies for candidal infections. Alternative drug delivery approaches, such as probiotics, reviewed here is likely to be a reality in clinical settings in the not too distant future.

One small step for a yeast--microevolution within macrophages renders Candida glabrata hypervirulent due to a single point mutation

Candida glabrata is one of the most common causes of candidemia, a life-threatening, systemic fungal infection, and is surpassed in frequency only by Candida albicans. Major factors contributing to the success of this opportunistic pathogen include its ability to readily acquire resistance to antifungals and to colonize and adapt to many different niches in the human body. Here we addressed the flexibility and adaptability of C. glabrata during interaction with macrophages with a serial passage approach. Continuous co-incubation of C. glabrata with a murine macrophage cell line for over six months resulted in a striking alteration in fungal morphology: The growth form changed from typical spherical yeasts to pseudohyphae-like structures – a phenotype which was stable over several generations without any selective pressure. Transmission electron microscopy and FACS analyses showed that the filamentous-like morphology was accompanied by changes in cell wall architecture. This altered growth form permitted faster escape from macrophages and increased damage of macrophages. In addition, the evolved strain (Evo) showed transiently increased virulence in a systemic mouse infection model, which correlated with increased organ-specific fungal burden and inflammatory response (TNFα and IL-6) in the brain. Similarly, the Evo mutant significantly increased TNFα production in the brain on day 2, which is mirrored in macrophages confronted with the Evo mutant, but not with the parental wild type. Whole genome sequencing of the Evo strain, genetic analyses, targeted gene disruption and a reverse microevolution experiment revealed a single nucleotide exchange in the chitin synthase-encoding CHS2 gene as the sole basis for this phenotypic alteration. A targeted CHS2 mutant with the same SNP showed similar phenotypes as the Evo strain under all experimental conditions tested. These results indicate that microevolutionary processes in host-simulative conditions can elicit adaptations of C. glabrata to distinct host niches and even lead to hypervirulent strains.

Evolution is not limited to making new species emerge and others perish over the millennia. It is also a central force in shorter-term interactions between microbes and hosts. A good example can be found in fungi, which are an underestimated cause of human diseases. Some fungi exist as commensals, and have adapted well to life on human epithelia. But as facultative pathogens, they face a different, hostile environment. We tested the ability of C. glabrata, a pathogen closely related to baker's yeast, to adapt to macrophages. We found that by adaptation, it changed its growth type completely. This allowed the fungus to escape the phagocytes, and increased its virulence in a mouse model. Sequencing the complete genome revealed surprisingly few mutations. Further analyses allowed us to detect the single mutation responsible for the phenotype, and to recreate it in the parental strain. Our work shows that fungi can adapt to immune cells, and that this adaptation can lead to an increased virulence. Since commensals are continuously exposed to host cells, we suggest that this ability could lead to unexpected phenotype changes, including an increase in virulence potential.

Antifungal drug resistance in Candida species

Invasive Candida infections are well established infectious entities of immunocompromised or critically ill patients and are characterised by high morbidity and mortality. Owing to the common eukaryotic structure of fungi and humans, a limited number of antifungal drugs is available for therapeutic purposes. In this unsatisfactory scenario, the emergence of drug resistance represents an important health problem. Failure of antifungal treatment can be related to host factors, to the pharmacokinetic and pharmacodynamic parameters of the drug, or to morphological, reproductive modalities and biofilm production of the fungus itself. Innate or acquired antifungal resistance derives from the presence or onset of molecular mechanisms related to the toxic activity of the drug itself. The resulting resistance can thus be extended to different molecules of the same class according to a greater or lesser affinity of the molecules for the target. In addition, non-specific cellular mechanisms of extrusion of toxic substances, such as overexpression of efflux pumps, can play a role involving different antifungal classes. Here we briefly review the current antifungal susceptibility testing methods and their usefulness as predictors of antifungal resistance in Candida spp., focusing on assessment of the involved molecular mechanisms.

Candida infections, causes, targets, and resistance mechanisms: traditional and alternative antifungal agents

The genus Candida includes about 200 different species, but only a few species are human opportunistic pathogens and cause infections when the host becomes debilitated or immunocompromised. Candida infections can be superficial or invasive. Superficial infections often affect the skin or mucous membranes and can be treated successfully with topical antifungal drugs. However, invasive fungal infections are often life-threatening, probably due to inefficient diagnostic methods and inappropriate initial antifungal therapies. Here, we briefly review our current knowledge of pathogenic species of the genus Candida and yeast infection causes and then focus on current antifungal drugs and resistance mechanisms. An overview of new therapeutic alternatives for the treatment of Candida infections is also provided.

Interventions for prevention and treatment of vulvovaginal candidiasis in women with HIV infection

BACKGROUND

Vulvovaginal candidiasis (VVC) is one of the most common fungal infections that recur frequently in HIV infected women. Symptoms of VVC are pruritis, discomfort, dyspareunia, and dysuria. Vulval infection presents as a morbiliform rash that may extend to the thighs. Vaginal infection is associated with white discharge, and plaques are seen on erythematous vaginal walls.Even though rarely or never resulting in systemic fungal infection or mortality, left untreated these lesions contribute considerably to the morbidity associated with HIV infection. Prevention and treatment of this condition is an essential part of maintaining the quality of life for these individuals.

OBJECTIVES

-To compare the efficacy of various antifungals given vaginally or orally for the treatment and prophylaxis of VVC in HIV-infected women and to evaluate the risks of the same.

SEARCH STRATEGY

The search strategy was comprehensive, iterative and based on that of the HIV/AIDS Cochrane Review Group. The aim was to locate all relevant trials, irrespective of publication status or language. Electronic databases :CENTRAL,Medline, EMBASE, LILACS and CINAHL were searched for randomised controlled trials for the years 1980 to 1st October 2010. WHO ICTRP site and other relevant web sites were also searched for conference abstracts.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of palliative, preventative or curative therapy were considered. Participants were HIV positive women receiving one or more of the following:treatment / prophylaxis for VVC or HAART(Highly Active Antiretroviral Therapy).

DATA COLLECTION AND ANALYSIS

Three authors independently assessed the methodological quality of the trials and extracted data. The quality of the evidence generated was graded using the GRADE PRO approach.

MAIN RESULTS

Our search did not yield any trial investigating treatment of VVC in HIV positive women.Two trials dealing with prophylaxis were eligible for inclusion.One trial (n= 323) favoured the use of weekly Fluconazole as compared to placebo (RR 0.68; 95% CI 0.47 to 0.97).The second trial with three arms of comparison;Clotrimazole,Lactobacillus and Placebo gave no definitive results in preventing an episode of VVC. Clotrimazole against placebo (RR 0.49; 95% CI 0.22 to 1.09), Clotrimazole against lactobacillus (RR 1.11; 95% CI 0.45 to 2.76) and lactobacillus against placebo (RR 0.54 ;95% CI 0.26 to 1.13).

AUTHORS' CONCLUSIONS

Implications for practiceNo trials were found addressing treatment of VVC in HIV positive women.In comparison to placebo,Fluconazole was found to be an effective preventative intervention. However, the potential for resistant Candida organisms to develop might impact the feasibility of implementation.Direction of findings suggests that Clotrimazole and Lactobacillus improved the prophylactic outcomes when compared to placebo.Implications for research There is a need to evaluate drugs and drug regimens for VVC treatment and prophylaxis in HIV positive women through randomised clinical trials. Development of resistance to azoles remains under-studied and more work must be done in this area, so as to determine whether routine prophylaxis for VVC is at all needed or whether adequate ART would be sufficient to prevent recurrent VVC. The viral load in vaginal secretions with or without treatment or prophylaxis has not been studied, this is very relevant to the spread of HIV.

Microbiological screening of Irish patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy reveals persistence of Candida albicans strains, gradual reduction in susceptibility to azoles, and incidences of clinical signs of oral candidiasis without culture evidence

Patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) are prone to chronic mucocutaneous candidiasis, which is often treated with azoles. The purpose of this study was to characterize the oral Candida populations from 16 Irish APECED patients, who comprise approximately half the total number identified in Ireland, and to examine the effect of intermittent antifungal therapy on the azole susceptibility patterns of Candida isolates. Patients attended between one and four clinical evaluations over a 5-year period, providing oral rinses and/or oral swab samples each time. Candida was recovered from 14/16 patients, and Candida albicans was the only Candida species identified. Interestingly, clinical diagnosis of candidiasis did not correlate with microbiological evidence of Candida infection at 7/22 (32%) clinical assessments. Multilocus sequence typing analysis of C. albicans isolates recovered from the same patients on separate occasions identified the same sequence type each time. Fluconazole resistance was detected in isolates from one patient, and isolates exhibiting a progressive reduction in itraconazole and/or fluconazole susceptibility were identified in a further 3/16 patients, in each case correlating with the upregulation of CDR- and MDR-encoded efflux pumps. Mutations were also identified in the ERG11 and the TAC1 genes of isolates from these four patients; some of these mutations have previously been associated with azole resistance. The findings suggest that alternative Candida treatment options, other than azoles such as chlorhexidine, should be considered in APECED patients and that clinical diagnosis of oral candidiasis should be confirmed by culture prior to the commencement of anti-Candida therapy.

The effect of cumulative length of hospital stay on the antifungal resistance of Candida strains isolated from critically ill surgical patients

Fluconazole is the first line of therapy for the management of candidiasis. However, fluconazole-resistant strains pose an emerging challenge in everyday clinical practice. In this study, we sought to determine whether cumulative length of hospital stay (CLOS) is a predictive factor for the acquisition of non-susceptible Candida strains to fluconazole. Thirty-three critically ill emergency surgery patients with 56 Candida isolates were enrolled in this prospective study. We divided our isolates according to their minimum inhibitory concentration (MIC) to fluconazole using 8 mcg/ml as a cutoff. We then compared the two groups with respect to basic demographics, antifungal agents prescribed, number of wide-spectrum antibiotics, duration of central venous catheter placement, elapsed time to positive culture, duration of prior hospital stay, and length of hospital stay. Non-susceptible fluconazole samples belonged to patients with a significantly longer prior hospital stay and a longer CLOS (P = 0.02 and 0.01, respectively). The difference between the 2 groups regarding non-albicans strains was statistically significant (P < 0.001). By fitting a non-parametric receiver-operating characteristics (ROC) curve into our analysis, a CLOS ≥ 29 days predicted the occurrence of non-susceptible strains with 90% sensitivity and 79.6% specificity (correct classification 81.5%). A CLOS ≥ 29 days is a strong predictor for the isolation of non-susceptible Candida isolates to fluconazole among critically ill emergency surgery patients. Clinicians should consider the duration of previous hospital stay when deciding on empiric antifungal therapy.

Mechanisms of antifungal drug resistance in Candida dubliniensis

Candida dubliniensis was first described in 1995 and is the most closely related species to the predominant human fungal pathogen Candida albicans. C. dubliniensis is significantly less prevalent and less pathogenic than C. albicans and is primarily associated with infections in HIV-infected individuals and other immunocompromised cohorts. The population structure of C. dubliniensis consists of three well-defined major clades and is significantly less diverse than C. albicans. The majority of C. dubliniensis isolates are susceptible to antifungal drugs commonly used to treat Candida infections. To date only two major patterns of antifungal drug resistance have been identified and the molecular mechanisms of these are very similar to the resistance mechanisms that have been described previously in C. albicans. However, significant differences are evident in the predominant antifungal drug mechanisms employed by C. dubliniensis, differences that reflect its more clonal nature, its lower prevalence and characteristics of its genome, the complete sequence of which has only recently been determined.

Vulvovaginal candidosis

Despite therapeutic advances, vulvovaginal candidosis remains a common problem worldwide, affecting all strata of society. Understanding of anti-candida host defence mechanisms in the vagina has developed slowly and, despite a growing list of recognised risk factors, a fundamental grasp of pathogenic mechanisms continues to elude us. The absence of rapid, simple, and inexpensive diagnostic tests continues to result in both overdiagnosis and underdiagnosis of vulvovaginal candidosis. I review the epidemiology and pathogenesis of this infection, and also discuss management strategies.

Risk of resistance associated with fluconazole prophylaxis: systematic review

BACKGROUND

Several studies have shown that fluconazole prophylaxis reduces the risk of fungal colonization and of invasive fungal infection in high-risk patients with minimal toxicity. This systematic review was designed to estimate the risk of emergence of colonization and infection either with azole susceptible-dose dependent or with resistant strains.

METHODS

We searched Medline, EMBASE, the Cochrane Collaboration database and our own files for randomized controlled trials assessing the effect of fluconazole on the incidence of fluconazole-resistant strains.

RESULTS

This systematic review of randomized clinical trials shows that fluconazole prophylaxis increases the risk for colonization with fluconazole susceptible-dose dependent or with resistant yeasts, the percentage of non-albicans Candida isolates and the percentage of fluconazole susceptible-dose dependent or resistant fungal isolates. Fluconazole prophylaxis did not significantly affect the risk of invasive disease with fluconazole susceptible-dose dependent or resistant fungi. The sample size was too small to assess the effect of fluconazole prophylaxis on the risk for breakthrough infections with non-albicans Candida.

CONCLUSION

Evidence from randomized trials suggests that fluconazole prophylaxis increases the risk for colonization with fluconazole susceptible-dose dependent or with resistant fungi, but does not significantly affect the risk for invasive infections with fluconazole susceptible-dose dependent or with resistant fungi. The risk for breakthrough infections remains a concern and needs to be addressed in large prospective studies.

Management of recurrent vulvovaginal candidiasis: Unresolved issues

The introduction and widespread use of long-term maintenance suppressive fluconazole prophylaxis for recurrent vulvovaginal candidiasis (RVVC) has improved the quality of life for thousands of women worldwide. Moreover, the regimen is no longer expensive, and it is safe and well tolerated. However, the regimen frequently fails to cure the condition and serves only as an effective control measure in many cases. Moreover, some women are unable to tolerate the regimen, and new curative approaches are needed. This review presents the limitations of this suppressive regimen and a discussion of the possible reasons for these limitations and failure to cure. Also, the rationale for new drug development is reviewed here.

In vitro antifungal susceptibility to six antifungal agents of 229 Candida isolates from patients with diabetes mellitus

The most common antifungal drugs in current clinical use for the treatment of oral candidosis are polyenes and azoles, mainly used topically. Poor glycaemic control in association with other local factors, such as the presence of oral dental prostheses, salivary pH, salivary flow rate and tobacco habits, may lead to the development of oral candidosis. Topical antifungal agents are frequently used to prevent the development of candidal infections in patients with poor metabolic control, particularly in the elderly wearing dentures. The aim of this study was to assess the antifungal susceptibility of Candida isolates to six antifungal agents using a commercially available kit, Fungitest. The isolated were collected from patients affected by diabetes mellitus from two different geographic localities (London, UK, and Parma, Italy) and from a group of healthy non-diabetic subjects. No differences in antifungal susceptibility to the six agents tested were observed between Candida isolates from diabetic and non-diabetic subjects. However, differences were observed between the two geographically different diabetes mellitus populations. Oral yeast isolates from diabetes mellitus patients in the UK more often displayed resistance or intermediate resistance to fluconazole (P=0.02), miconazole (P<0.0001), and ketoconazole (P=0.01) than did isolates from diabetes mellitus patients in Italy. In addition, more C. albicans isolates were found in diabetic and non-diabetic subjects that were susceptible to fluconazole (P=0.0008 and P=0.01, respectively) than non-albicans isolates. The difference in the antifungal resistance of isolates from the two populations of diabetes mellitus patients may be related to differences in the therapeutic management of candidal infections between the two centres.

Targeted short-term fluconazole prophylaxis among very low birth weight and extremely low birth weight infants

OBJECTIVES

To assess whether targeted short-term fluconazole prophylaxis reduces late-onset (>3 days of age) invasive fungal infection (IFI) among very low birth weight infants and extremely low birth weight (ELBW) infants and to assess mortality rates, toxicity, and costs associated with this intervention.

METHODS

An observational study of 2 subsequent epochs of inborn infants with birth weight of <1500 g or gestational age of <32 weeks, 1 before (control) and 1 after (fluconazole) initiation of routine targeted fluconazole prophylaxis in March 2003, was performed. Targeted fluconazole (3 mg/kg) prophylaxis was administered to infants for whom a decision was made to administer broad-spectrum antibiotics for >3 days.

RESULTS

IFI was observed for 13 (6.3%) of 206 infants in the control epoch and 2 (1.1%) of 178 in the fluconazole epoch, with a common odds ratio of 0.166. Logistic regression analysis taking into account all published factors (except for fungal colonization) showed that the fluconazole epoch was associated significantly with lower IFI rates. We observed no change in late (>3 days) mortality rates (11 of 206 infants in the control epoch vs 8 of 178 infants in the prophylaxis epoch). The mortality rate for ELBW infants with IFI was low (15%) in our study. Fluconazole was administered to 81% of ELBW infants, who received a median of 8 doses, and 41% of larger infants, who received a median of 5 doses. The intervention was cost-effective, and the effective number needed to treat to prevent 1 IFI was 10.

CONCLUSIONS

This study suggests that targeted short-course fluconazole prophylaxis in very low birth weight and ELBW infants may be efficacious and cost effective.

Fluconazole for the management of invasive candidiasis: where do we stand after 15 years?

Candida spp. are responsible for most of the fungal infections in humans. Available since 1990, fluconazole is well established as a leading drug in the setting of prevention and treatment of mucosal and invasive candidiasis. Fluconazole displays predictable pharmacokinetics and an excellent tolerance profile in all groups, including the elderly and children. Fluconazole is a fungistatic drug against yeasts and lacks activity against moulds. Candida krusei is intrinsically resistant to fluconazole, and other species, notably Candida glabrata, often manifest reduced susceptibility. Emergence of azole-resistant strains as well as discovery of new antifungal drugs (new triazoles and echinocandins) have raised important questions about its use as a first line drug. The aim of this review is to summarize the main available data on the position of fluconazole in the prophylaxis or curative treatment of invasive Candida spp. infections. Fluconazole is still a major drug for antifungal prophylaxis in the setting of transplantation (solid organ and bone marrow), intensive care unit, and in neutropenic patients. Prophylactic fluconazole still has a place in HIV-positive patients in viro-immunological failure with recurrent mucosal candidiasis. Fluconazole can be used in adult neutropenic patients with systemic candidiasis, as long as the species identified is a priori susceptible. Among non-neutropenic patients with candidaemia fluconazole is one of the first line drugs for susceptible species. Cases reports and uncontrolled studies have also reported its efficacy in the setting of osteoarthritis, endophthalmitis, meningitis, endocarditis and peritonitis caused by Candida spp. among immunocompetent adults. In paediatrics, fluconazole is a well tolerated and major prophylactic drug for high-risk neonates, as well as an alternative treatment for neonatal candidiasis. Importantly 15 years after its introduction in the antifungal armamentarium, fluconazole is still a first line treatment option in several cases of invasive candidiasis. Its prophylactic use should however be limited to selected high-risk patients to limit the risk of emergence of azole-resistant strains.

International, open-label, noncomparative, clinical trial of micafungin alone and in combination for treatment of newly diagnosed and refractory candidemia

Candida spp. are the fourth leading cause of bloodstream infections, and non-albicans species are increasing in importance. Micafungin is a new echinocandin antifungal agent with excellent in vitro activity against Candida spp. Pediatric, neonatal, and adult patients with new or refractory candidemia were enrolled into this open-label, noncomparative, international study. The initial dose of micafungin was 50 mg/d (1 mg/kg for patients <40 kg) for infections due to C. albicans and 100 mg/d (2 mg/kg for patients <40 kg) for infections due to other species. Dose escalation was allowed. Maximum length of therapy was 42 days. A total of 126 patients were evaluable (received at least five doses of micafungin). Success (complete or partial response) was seen in 83.3% patients overall. Success rates for treatment of infections caused by the most common Candida spp. were as follows: C. albicans 85.1%, C. glabrata 93.8%, C. parapsilosis 86.4%, and C. tropicalis 83.3%. Serious adverse events related to micafungin were uncommon. Micafungin shows promise as a safe and effective agent for the treatment of newly diagnosed and refractory cases of candidemia. Large-scale, randomized, controlled trials are warranted.

Impact of fluconazole prophylaxis on incidence and outcome of invasive candidiasis in a neonatal intensive care unit

OBJECTIVES

We assessed the impact of intravenous fluconazole prophylaxis (FP) in extremely low birth weight (ELBW [<1000 g]) infants on the incidence of and outcome from invasive candidiasis (IC) in all infants admitted to a neonatal intensive care unit (NICU).

STUDY DESIGN

Beginning April 1, 2002, FP was given to ELBW infants aged < 5 days admitted to the NICU of Woman's Hospital of Texas. Infants in NICU in whom IC developed during the first 2 years of FP (FP period) were compared with those with IC during 2000-2001.

RESULTS

During 2000-2001 and the FP period, the incidence of IC in ELBW infants decreased from 7% (15 of 206) to 2% (5 of 240) (P=.01), and the IC-related mortality rate decreased from 12% (4 of 33) to 0 (0 of 40) (P=.04); the incidence of IC increased from 0.1% (4 of 2806) to 0.2% (8 of 3372) in infants of birth weight > or = 1000 g (P=.06), and no IC-related deaths occurred. During the FP period, IC developed in older infants (24 vs 12 days; P=.12) who had similar risk factors for IC.

CONCLUSION

Invasive candidiasis occurred in our NICU in spite of FP and shifted to bigger, more mature infants who had a better outcome.

Utility of real-time antifungal susceptibility testing for fluconazole in the treatment of candidemia

Our study prospectively examined the use of real-time antifungal susceptibility testing among 119 patients with candidemia at a large tertiary university medical center over a 1-year period. Susceptibility results to fluconazole were reported to physicians a mean of 5.1 days after the initial positive blood culture for Candida. Physicians believed that receiving antifungal susceptibility testing results was helpful and not infrequently altered therapy on the basis of results. Outcomes, including mortality and resolution of infection, among 20 (17%) patients with fluconazole-resistant and fluconazole-susceptible dose-dependent isolates were relatively poor compared to those among patients with fluconazole-susceptible isolates, but probably reflect severity of illness. Routine susceptibility testing as an adjunct to the treatment of candidemia has significant potential and warrants further study.

Antifungal susceptibility survey of 2,000 bloodstream Candida isolates in the United States

Candida bloodstream isolates (n = 2,000) from two multicenter clinical trials carried out by the National Institute of Allergy and Infectious Diseases Mycoses Study Group between 1995 and 1999 were tested against amphotericin B (AMB), flucytosine (5FC), fluconazole (FLU), itraconazole (ITR), voriconazole (VOR), posaconazole (POS), caspofungin (CFG), micafungin (MFG), and anidulafungin (AFG) using the NCCLS M27-A2 microdilution method. All drugs were tested in the NCCLS-specified RPMI 1640 medium except for AMB, which was tested in antibiotic medium 3. A sample of isolates was also tested in RPMI 1640 supplemented to 2% glucose and by using the diluent polyethylene glycol (PEG) in lieu of dimethyl sulfoxide for those drugs insoluble in water. Glucose supplementation tended to elevate the MIC, whereas using PEG tended to decrease the MIC. Trailing growth occurred frequently with azoles. Isolates were generally susceptible to AMB, 5FC, and FLU. Rates of resistance to ITR approached 20%. Although no established interpretative breakpoints are available for the candins (CFG, MFG, and AFG) and the new azoles (VOR and POS), they all exhibited excellent antifungal activity, even for those strains resistant to the other aforementioned agents.

Persistence of oropharyngeal Candida albicans strains with reduced susceptibilities to fluconazole among human immunodeficiency virus-seropositive children and adults in a long-term care facility

Nineteen oropharyngeal Candida albicans isolates from six children and seven adults living with AIDS at the Russia AIDS Centre, Moscow, from 1990 to 1998 were selected for molecular typing. Two fluconazole-resistant C. albicans genotypes were identified from a child who contracted human immunodeficiency virus infection during the Elista Hospital outbreak in the Kalmyk Republic in 1989. Highly related strains were observed 4 years later in the oral lesions and colonization of two patients and a health care worker. There may be a tendency for persons who are living with AIDS in a long-term care facility and who receive fluconazole therapy for oropharyngeal candidiasis to harbor and spread fluconazole-resistant C. albicans strains.

Activities of fluconazole and voriconazole against 1,586 recent clinical isolates of Candida species determined by Broth microdilution, disk diffusion, and Etest methods: report from the ARTEMIS Global Antifungal Susceptibility Program, 2001

The ARTEMIS Global Antifungal Susceptibility Program (ARTEMIS Program) was initiated in 2001 to provide focused surveillance of the activities of fluconazole and voriconazole against Candida spp. isolated from blood and other normally sterile sites. A total of 1,586 episodes of infection were detected at 61 international study sites. Overall, 57.7% of the infections were due to Candida albicans, followed by C. glabrata (14.8%), C. parapsilosis (12.5%), C. tropicalis (9.4%), C. krusei (2.7%), and C. lusitaniae (1.5%). Isolates of C. albicans, C. parapsilosis, and C. tropicalis were all highly susceptible to fluconazole (for 99% of the isolates the MICs were Collapse

Key Words Collapse

MESH Headings

• Antifungal Agents/pharmacology
• Candida/classification
• Candida/drug effects
• Candida/isolation & purification
• Candidiasis/microbiology
• Drug Resistance, Fungal
• Fluconazole/pharmacology
• Humans
• Microbial Sensitivity Tests/methods
• Population Surveillance
• Pyrimidines/pharmacology
• Triazoles/pharmacology
• Voriconazole

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Affiliation(s)

M A Pfaller Department of Pathology, Roy J. and Lucille A. Carver College of Medicine and College of Public Health, University of Iowa, Iowa City, Iowa 52242, USA.
D J Diekema
S A Messer
L Boyken
R J Hollis

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Interplay between protective and inhibitory antibodies dictates the outcome of experimentally disseminated Candidiasis in recipients of a Candida albicans vaccine

Mice immunized with heat-inactivated, whole yeast-form cells (Y cells) of Candida albicans developed intense, specific humoral and cell-mediated immune responses. However, they were modestly protected against a lethal challenge by the fungus, and their sera did not confer passive protection upon nonimmunized animals. Surprisingly, this immune serum conferred an elevated degree of passive protection to normal and SCID mice when preadsorbed on whole C. albicans cells. After adsorption, no antibodies specific to mannoprotein (MP)-rich extracts or secretions were detected by indirect enzyme-linked immunosorbent assay and no serum reaction with the fungal cell surface was seen in immunofluorescence assays. However, this serum had totally preserved the level of other antibodies, in particular those reacting with beta-1,3 and beta-1,6 glucan (GG). The hypothesis that anti-GG antibodies contributed to the passive protection was suggested by the following circumstantial evidence: (i) mice immunized with C. albicans cells treated with dithiothreitol and protease (YDP cells), which exposed GG on their surfaces and generated anti-GG but not anti-MP antibodies, were substantially protected against a lethal fungus challenge; (ii) the sera, and their immunoglobulin fractions, of mice immunized with YDP cells transferred protection to nonimmune animals; and (iii) this passive protection was substantially abolished by preadsorption on GG but not on intact cells. Overall, our findings demonstrate that some anti-Candida antibodies can block the protective potential of immune serum, a potential to which anti-GG antibodies appear to contribute. Our observations may also help explain why subjects with elevated anti-Candida antibody titers, inclusive of anti-MP and anti-GG antibodies, remain nonetheless susceptible to invasive candidiasis.

Prospective, multicenter surveillance study of Candida glabrata: fluconazole and itraconazole susceptibility profiles in bloodstream, invasive, and colonizing strains and differences between isolates from three urban teaching hospitals in New York City (Candida Susceptibility Trends Study, 1998 to 1999)

Since the 1990s, the substantial increase in the rate of Candida glabrata infections has become a serious problem. As most C. glabrata infections arise from the host's endogenous microflora, the present prospective, multicenter analysis included all clinical isolates associated with colonization and with systemic and hematogenous candidiasis. Among 347 C. glabrata isolates, the overall rates of resistance to fluconazole (MIC > or = 64 micro g/ml) and itraconazole (MIC > or = 1 micro g/ml) were 10.7 and 15.2%, respectively, although for half (n = 148) of the itraconazole-susceptible isolates the MICs (0.25 to 0.5 micro g/ml) were in the susceptible-dependent upon dose range. Fluconazole resistance was more common among C. glabrata isolates obtained from centers caring for patients with cancer (MICs at which 90% of isolates are inhibited [MIC(90)s] = 32 micro g/ml) or AIDS (MIC(90)s > 64 micro g/ml) than among C. glabrata isolates from a community-based university medical center (MIC(90)s = 16 micro g/ml) (P = 0.001). Thirty-three bloodstream isolates and those obtained from other body sites had similar in vitro susceptibility profiles. The fluconazole MIC(90)s (< or =16 micro g/ml) for C. glabrata yeast isolates from the gastrointestinal tract were lower than those (> or =64 micro g/ml) for C. glabrata isolates from respiratory and urinary tract samples (P = 0.01). A similar discrepancy for itraconazole was not significant (P > 0.5). We did not observe differences in fluconazole or itraconazole susceptibility profiles among C. glabrata isolates associated with either hematogenous dissemination or colonization. The significant discrepancy in antifungal susceptibility among C. glabrata organisms isolated from hospitals in the same geographic region emphasizes the significance of periodic susceptibility surveillance programs for individual institutions, especially those providing care to patients at risk.

Secular trend of hospital-acquired candidemia among intensive care unit patients in the United States during 1989-1999

We describe the annual incidence of primary bloodstream infection (BSI) associated with Candida albicans and common non-albicans species of Candida among patients in intensive care units that participated in the National Nosocomial Infections Surveillance system from 1 January 1989 through 31 December 1999. During the study period, there was a significant decrease in the incidence of C. albicans BSI (P<.001) and a significant increase in the incidence of Candida glabrata BSI (P=.05).