Fluconazole in the management of fungal urinary tract infections

Whole genome sequencing analysis demonstrates therapy-induced echinocandin resistance in Candida auris isolates

Candida auris is an emerging, multidrug-resistant yeast, causing outbreaks in healthcare facilities. Echinocandins are the antifungal drugs of choice to treat candidiasis, as they cause few side effects and resistance is rarely found. Previously, immunocompromised patients from Kuwait with C. auris colonisation or infection were treated with echinocandins, and within days to months, resistance was reported in urine isolates. To determine whether the development of echinocandin resistance was due to independent introductions of resistant strains or resulted from intra-patient resistance development, whole genome sequencing (WGS) single-nucleotide polymorphism (SNP) analysis was performed on susceptible (n = 26) and echinocandin-resistant (n = 6) isolates from seven patients. WGS SNP analysis identified three distinct clusters differing 17-127 SNPs from two patients, and the remaining isolates from five patients, respectively. Sequential isolates within patients had a maximum of 11 SNP differences over a time period of 1-10 months. The majority of isolates with reduced susceptibility displayed unique FKS1 substitutions including a novel FKS1M690V substitution, and nearly all were genetically related, ranging from only three to six SNP differences compared to susceptible isolates from the same patient. Resistant isolates from three patients shared the common FKS1S639F substitution; however, WGS analysis did not suggest a common source. These findings strongly indicate that echinocandin resistance is induced during antifungal treatment. Future studies should determine whether such echinocandin-resistant strains are capable of long-term colonisation, cause subsequent breakthrough candidiasis, have a propensity to cross-infect other patients, or remain viable for longer time periods in the hospital environment.

Preparation, spectroscopic, characterizations and biological studies of new charge transfer complexes formed between fluconazole drug with various acceptors

Charge transfer complexes developed during the interaction of Fluconazole drug (FLU) as an electron donor with different types of electron acceptors, including σ-type as iodine (I₂), and π-types as 2,3-dinitrosalsylic acid (HDNS), Tetracyanoethylene (TCNE) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The formed complexes were characterized using various techniques as UV-Vis spectra, Thermal analyses, spectrophotometric measurements, ¹H NMR and FTIR Spectroscopy. It was found that the stoichiometry of all developed complexes was a 1:1 M ratio between fluconazole and acceptors (I₂, HDNS, TCNE and DDQ). The characteristic physical parameters data such as ionization potential (I_D), The oscillator strength (ƒ), formation constant (K_CT), transition dipole moment (μ), free energy (ΔG), and energy of interaction (E_CT) of the formed CT-complexes have also been reported. Eventually, the synthesized complexes were screened for their microbial and antioxidant activities.

Caracterización de Candida spp. aisladas a partir de urocultivos en la ciudad de Medellín

Candida spp. es un agente etiológico importante en infecciones del tracto urinario, principalmente en población con terapia antimicótica de amplio espectro y con catéteres urinarios. Candida albicans es la especie más frecuente, pero otras especies han surgido como patógenos emergentes. En este trabajo se recolectaron aislamientos de Candida spp. de urocultivos de pacientes que consultaron en Dinamica IPS entre enero 2016 y noviembre 2017. Para estimar la frecuencia de las especies y observar los patrones de sensibilidad, se realizó la identificación fenotípica y su perfil de sensibilidad con el sistema comercial Vitek 2® (BioMérieux, Inc.), adicionalmente se evaluaron mediante análisis de las secuencia y filogenética ITS1-5.8S-ITS2. En el estudio se incluyeron 78 aislamientos de Candida spp. Las frecuencias de especies de Candida identificadas empleando las herramientas moleculares fueron: C. albicans (38,5%), C. tropicalis (23,1%), C. glabrata (21,8%), C. parapsilosis (10,3%), C. metapsilosis y C. krusei (2,5%) y C. guillermondi (1,3%). La identificación por métodos moleculares y por el sistema Vitek 2 fue: C. albicans (93,3%), C. glabrata (94,1 %), C. tropicalis (83,3%), C. parapsilosis (75%) C. guilliermondii y C. krusei (100%). La sensibilidad de todos los aislamientos al fluconazol fue 93,6%.

[Urinary tract infection by Candida species]

OBJECTIVES

To determine the frequency and characteristics of urinary tract infection (UTI) by Candida in diabetic patients (with and without symptoms) and to compare them with non-diabetic patients (with and without symptoms).

DESIGN

Longitudinal, descriptive, and observational study.

SETTING

Study conducted at the "Dr Ignacio Chavez" Clinic of family medicine, ISSSTE: Mexico.

PARTICIPANTS

There were 2 kinds of patients; 1 with diabetes mellitus diagnosis (DM) with and without clinical picture of probable urinary tract infection (UTI), and 1 without DM and with and without clinical picture of probable UTI.

MAIN MEASUREMENTS

A urine culture and a confidential questionnaire were administered to find the presence of urinary symptoms and likely risk factors associated with the infection. To associate these risks, the chi2 statistical method was used, with significance at 95% and Fisher's Exact Test for small frequencies, using the EpiInfo V.6.0 program.

RESULTS

Two hundred thirty seven patients between 28 and 82 years old were included. The prevalence of urinary infection by Candida was 5.1%, but only 33% of these had C albicans. There was no association between candidiasis and factors like age, sex, or presence of DM, but it was related to previous treatments, previous UTI and the evolution time of DM.

CONCLUSIONS

The conscious search by both doctor and laboratory for Candida micro-organisms as factors causing UTI is important. This is especially so in those patients with factors of risk that may condition Candida's presence.

[Candiduria in intensive care unit: significance and value of yeast numeration in urine]

JUSTIFICATION

Candiduria is increasingly frequent among patients admitted to intensive care units but its significance remains unclear.

OBJECTIVES

Search for eventual correlation between quantitative candiduria and known risk factors for invasive candidiasis.

STUDY DESIGN

Prospective.

PATIENTS AND METHODS

A four-month study was conducted in 162 patients hospitalized in the intensive care unit for more than 72 hours. All patients underwent a weekly research of candiduria added to sampling from different body sites to determine the Pittet Candida colonization index.

RESULTS

Candiduria has been proved in 56 cases (34%). It was superior or equal to 10(4) UFC/ml among 28 patients (50%). Candida tropicalis, Candida glabrata and Candida albicans has been isolated in 41, 22 and 20% respectively. All patients had at least one major and two minor risk factors for Candida infection. Six patients (10%) developed invasive candidiasis. The global mortality rate was at 52%. Pittet colonization index was significantly different between patients with candiduria and those with invasive candidiasis (p=0.01). There was a statistically significant correlation between candiduria superior or equal to 10(4) UFC/ml and Pittet colonization index superior or equal to 0.5 (p=0.01).

CONCLUSION

Candiduria superior or equal to 10(4) UFC/ml associated with risk factors may predict invasive candidiasis in critically ill patients.

The longest use of liposomal amphotericin B and 5-fluorocytosine in neonatal renal candidiasis

Bilateral fungal obstruction of the renal collecting system is rare in infancy. Treatment options include medical or surgical procedures. Reports of successful medical treatment with liposomal amphotericin B have been published but the duration of treatment is controversial. We report a 3-week-old preterm baby with myelomeningocele who had experienced acute renal failure related to bilateral renal fungus balls, which improved with percutaneous nephrostomy and 12 weeks of liposomal amphotericin B intravenously combined with 5-fluorocytosine orally for 9 weeks.

Candidal urinary tract infections caused by non-albicans Candida species

The incidence of non-albicans Candida and non-Candida species isolated from the urine of patients admitted to various departments of the Faculty Hospital of the Medical Faculty of Safárik University in Kosice was examined. From a total of 94 samples of analyzed urine 58 strains of C. albicans and 36 strains of yeasts belonging to 6 species of non-albicans Candida and non-Candida spp. were detected: C. parapsilosis (n = 23), C. tropicalis (6), C. krusei (3), C. robusta (2), C. catenulata (1) and Cryptococcus neoformans (1). In relation to the diagnosis, the yeasts were isolated from patients suffering from a kidneys disease, epididymitis, diabetes, neoplastic diseases, urogenital anomalies, obstructive uropathy, cystitis, prostatitis, hemolytic-uremic syndrome, and others.

Commonly used antibacterial and antifungal agents for hospitalised paediatric patients: implications for therapy with an emphasis on clinical pharmacokinetics

Due to normal growth and development, hospitalised paediatric patients with infection require unique consideration of immune function and drug disposition. Specifically, antibacterial and antifungal pharmacokinetics are influenced by volume of distribution, drug binding and elimination, which are a reflection of changing extracellular fluid volume, quantity and quality of plasma proteins, and renal and hepatic function. However, there is a paucity of data in paediatric patients addressing these issues and many empiric treatment practices are based on adult data. The penicillins and cephalosporins continue to be a mainstay of therapy because of their broad spectrum of activity, clinical efficacy and favourable tolerability profile. These antibacterials rapidly reach peak serum concentrations and readily diffuse into body tissues. Good penetration into the cerebrospinal fluid (CSF) has made the third-generation cephalosporins the agents of choice for the treatment of bacterial meningitis. These drugs are excreted primarily by the kidney. The carbapenems are broad-spectrum beta-lactam antibacterials which can potentially replace combination regimens. Vancomycin is a glycopeptide antibacterial with gram-positive activity useful for the treatment of resistant infections, or for those patients allergic to penicillins and cephalosporins. Volume of distribution is affected by age, gender, and bodyweight. It diffuses well across serous membranes and inflamed meninges. Vancomycin is excreted by the kidneys and is not removed by dialysis. The aminoglycosides continue to serve a useful role in the treatment of gram-negative, enterococcal and mycobacterial infections. Their volume of distribution approximates extracellular space. These drugs are also excreted renally and are removed by haemodialysis. Passage across the blood-brain barrier is poor, even in the face of meningeal inflammation. Low pH found in abscess conditions impairs function. Toxicity needs to be considered. Macrolide antibacterials are frequently used in the treatment of respiratory infections. Parenteral erythromycin can cause phlebitis, which limits its use. Parenteral azithromycin is better tolerated but paediatric pharmacokinetic data are lacking. Clindamycin is frequently used when anaerobic infections are suspected. Good oral absorption makes it a good choice for step-down therapy in intra-abdominal and skeletal infections. The use of quinolones in paediatrics has been restricted and most information available is in cystic fibrosis patients. High oral bioavailability is also important for step-down therapy. Amphotericin B has been the cornerstone of antifungal treatment in hospitalised patients. Its metabolism is poorly understood. The half-life increases with time and can be as long as 15 days after prolonged therapy. Oral absorption is poor. The azole antifungals are being used increasingly. Fluconazole is well tolerated, with high bioavailability and good penetration into the CSF. Itraconazole has greater activity against aspergillus, blastomycosis, histoplasmosis and sporotrichosis, although it's pharmacological and toxicity profiles are not as favourable.

[Yeast count in urine. Review of the literature and preliminary results of a multicenter prospective study carried out in 15 hospital centers]

Candida spp. are increasingly involved in nosocomial infections in severely ill patients and the diagnosis is difficult. In this context, the significance of candiduria remains unclear. Management of this condition is still equivocal, because of the lack of information about its natural history and its predictive value for disseminated infection. Little is known about the discriminant value of colony count. After a comprehensive review of the available published data, the preliminary results of a multicentric prospective survey in critically ill patients hospitalised in intensive care units are given. The aim of the study was to search for correlations between quantitative candiduria and known risk factors for disseminated candidiasis. There is a statistically significant correlation (p = 0.003) between heavy candiduria (> 10(4) cfu.mL-1) and high Pittet colonisation index (> or = 0.5). Quantification of candiduria could be useful to select patients at high risk for disseminated candidiasis.

Agents for treatment of invasive fungal infections

The incidence of fungal infections continues to rise as the population of immunocompromised individuals increases. Despite the enlarging numbers of infections, there are only a few antifungal agents for treatment of deep-seated, invasive infections. These agents include amphotericin B, flucytosine, terbinafine, and several azoles. Progress has been made in understanding the role of these agents in a variety of infections and this article examines in detail these agents and their prophylactic, empiric, and therapeutic uses in invasive mycoses. This article focuses on general concepts of antifungal therapies and provides a detailed review of each antifungal agent available for treatment of deep-seated mycoses.

Clinicians' reaction to positive urine culture for Candida organisms

Clinicians' reaction to isolating Candida organisms in urine culture (> or = 10(4) CFU ml-1) was assessed in a retrospective review of 133 consecutive in-patients (> or = 15 years-of-age) over a 5 month period. The average age was 68.8 years and male/female ratio was 0.36 (35/98). Most (78.2%) patients had an indwelling catheter, and many (35.3%) were in the intensive care unit (ICU). In response to culture-result, clinicians initiated antifungal therapy in 80 instances (60.2%). Treatment was often based on a single culture without documenting the infection (n = 53/80, 66.3%) in the absence of risk for invasive disease. Removing the indwelling-catheter was never attempted and antibiotics were rarely discontinued or modified (1.3%). Fluconazole was most frequently utilized (n = 42, 52.5%), followed by amphotericin-B bladder-irrigation (n = 26, 32.5%), and combined fluconazole/amphotericin-B bladder-irrigation (n = 12, 15%). Therapy was more frequently initiated in ICU-cases (76.6 versus 55.6%; P = 0.023) and less often in non-catheterized individuals (40.7 versus 69%; P = 0.012) and patients with 10(4) CFU ml-1 (25.9 versus 72.7%; P < 0.0001). These findings show that clinicians nowadays do not follow current guidelines for the management of candiduria. Efforts to increase clinicians' awareness of these guidelines, which are intended to confirm the diagnosis and stratify treatment according to patient risk factors, appear to be necessary.

Antifungal agents. Part II. The azoles

Before 1978, amphotericin B and flucytosine were the only drugs available for the treatment of systemic fungal infections. The imidazoles, miconazole and ketoconazole, were introduced during the next 3 years. Intravenously administered miconazole served a limited therapeutic role and is no longer available. Orally administered ketoconazole, an inexpensive, effective, and convenient option for treating mucosal candidiasis, was widely used for a decade because it was the only available oral therapy for systemic fungal infections. During the 1990s, use of ketoconazole diminished because of the release of the triazoles--fluconazole and itraconazole. Fluconazole is less toxic and has several pharmacologic advantages over ketoconazole, including penetration into the cerebrospinal fluid. In addition, it has superior efficacy against systemic candidiasis, cryptococcosis, and coccidioidomycosis. Despite a myriad of drug interactions and less favorable pharmacologic and toxicity profiles in comparison with fluconazole, itraconazole has become a valuable addition to the antifungal armamentarium. It has excellent activity against sporotrichosis and seems promising in the treatment of aspergillosis. Itraconazole has replaced ketoconazole as the therapy of choice for nonmeningeal, non-life-threatening cases of histoplasmosis, blastomycosis, and paracoccidioidomycosis and is effective in patients with cryptococcosis and coccidioidomycosis, including those with meningitis. Further investigation into the development of new antifungal agents is ongoing.

Fluconazole: comparison of pharmacokinetics, therapy and in vitro susceptibility

Fluconazole shows good penetration into the tissues and body fluids examined and a rapid equilibrium is achieved between the concentrations in the various compartments. The pharmacokinetics of fluconazole after intravenous or oral administration are proportional to the dose. This finding, together with the slow elimination of the triazole (t1/2 30 h), makes it easier to forecast the therapeutically effective dosage. Measurements of fluconazole concentration in blood can be used to predict levels in some tissues (lung, brain, gynaecological samples), body fluids (sputum, saliva, vaginal secretions) or exudates. Concentrations in cerebrospinal fluid and vitreous humour of the eye reach approximately 80% of the levels found in blood. A very high proportion of fluconazole is excreted unchanged in the urine, where concentrations of the drug are 10-20-fold higher than in blood. Whilst this pharmacokinetic profile is valuable in the treatment of fungal infections of the urinary tract, it also means that the dosage may need to be decreased in patients with renal impairment. The susceptibility of fungi to fluconazole in vitro and in vivo correlates well with the concentrations of the drug measured in various compartments of the body.

Azole resistance in Candida

Resistance of Candida to azoles is an increasing problem. Susceptibility testing of Candida against fluconazole and ketoconazole is now feasible and desirable. Good correlation of resistance in vitro with clinical failure of fluconazole therapy has now been shown in mucosal candidiasis. The relationship, if any, between resistance and clinical failure in the context of invasive candidiasis is not clear at present and additional correlative work needs to be done. Monitoring of resistance trends in Candida is clearly important now.

[Fluconazole: comparison of pharmacokinetics, therapy and in vitro susceptibility of yeasts]

Fluconazole penetrates well into the tissues and body fluids which were examined and achieves rapid equilibration between the different compartments. The pharmacokinetics of fluconazole are independent of the dose after oral or intravenous administration. This finding, together with the drug's slow elimination (t1/2 30 h) facilitate the estimation of the therapeutically effective dosage. The concentrations of fluconazole measured in blood can be extrapolated to the concentrations in tissue (lung, brain, gynecological tissues), body fluids (sputum, saliva, vaginal secretions) and exudates. The concentration of fluconazole in cerebrospinal fluid and in the vitreous humour of the eye is ca. 80% of that in blood. Fluconazole is predominantly excreted in the urine in the unchanged form, which explains the 10 to 20 fold higher concentration of the drug in urine relative to blood. Although this pharmacokinetic profile favours the use of fluconazole in mycotic infections of the urinary tract it also means that the dose of the drug may have to be adapted to lower regimens in the systemic treatment of patients with restricted kidney function. The in vitro and in vivo susceptibility of the yeasts correlates with the concentrations of fluconazole measured in the different compartments of the body.