Healthcare workers' hands as a vehicle for the transmission of virulent strains of Candida spp.: A virulence factor approach

Candida glabrata (Nakaseomyces glabrata): A systematic review of clinical and microbiological data from 2011 to 2021 to inform the World Health Organization Fungal Priority Pathogens List

Recognising the growing global burden of fungal infections, the World Health Organization (WHO) established an advisory group consisting of experts in fungal diseases to develop a Fungal Priority Pathogen List. Pathogens were ranked based on their research and development needs and perceived public health importance using a series of global surveys and pathogen characteristics derived from systematic reviews. This systematic review evaluates the features and global impact of invasive disease caused by Candida glabrata (Nakaseomyces glabrata). PubMed and Web of Science were searched for studies reporting on mortality, morbidity (hospitalization and disability), drug resistance (including isolates from sterile and non-sterile sites, since these reflect the same organisms causing invasive infections), preventability, yearly incidence, diagnostics, treatability, and distribution/emergence in the last 10 years. Candida glabrata (N. glabrata) causes difficult-to-treat invasive infections, particularly in patients with underlying conditions such as immunodeficiency, diabetes, or those who have received broad-spectrum antibiotics or chemotherapy. Beyond standard infection prevention and control measures, no specific preventative measures have been described. We found that infection is associated with high mortality rates and that there is a lack of data on complications and sequelae. Resistance to azoles is common and well described in echinocandins-in both cases, the resistance rates are increasing. Candida glabrata remains mostly susceptible to amphotericin and flucytosine. However, the incidence of the disease is increasing, both at the population level and as a proportion of all invasive yeast infections, and the increases appear related to the use of antifungal agents.

Virulence factors, antifungal susceptibility and molecular profile in Candida species isolated from the hands of health professionals before and after cleaning with 70% ethyl alcohol-based gel

Fungal infections in neonatal intensive care units (NICU) are mainly related to Candida species, with high mortality rates. They are predominantly of endogenous origin, however, cross-infection transmitted by healthcare professionals' hands has occurred. The aim of this study was to identify Candida species isolated from the hands of healthcare professionals in a NICU before and after hygiene with 70% ethanol-based gel and evaluate virulence factors DNase, phospholipase, proteinase, hemolysin, biofilm biomass production, and metabolic activity. In vitro antifungal susceptibility testing and similarity by random amplified polymorphic DNA (RAPD) were also performed. C. parapsilosis complex was the most frequent species (57.1%); all isolates presented at least one virulence factor; three isolates (Candida parapsilosis complex) were resistant to amphotericin B, two (Candida famata [currently Debaryomyces hansenii] and Candida guilliermondii [currently Meyerozyma guilliermondii]) was resistant to micafungin, and six (Candida parapsilosis complex, Candida guilliermondii [=Meyerozyma guilliermondii], Candida viswanathi, Candida catenulata [currently Diutina catenulata] and Candida lusitaniae [currently Clavispora lusitaniae]) were resistant to fluconazole. Molecular analysis by RAPD revealed two clusters of identical strains that were in the hands of distinct professionals. Candida spp. were isolated even after hygiene with 70% ethanol-based gel, highlighting the importance of stricter basic measures for hospital infection control to prevent nosocomial transmission.

Population genomic analyses reveal high diversity, recombination and nosocomial transmission among Candida glabrata (Nakaseomyces glabrata) isolates causing invasive infections

Candida glabrata is a commensal yeast of the gastrointestinal tract and skin of humans. However, it causes opportunistic infections in immunocompromised patients, and is the second most common Candida pathogen causing bloodstream infections. Although there are many studies on the epidemiology of C. glabrata infections, the fine- and large-scale geographical nature of C. glabrata remain incompletely understood. Here we investigated both the fine- and large-scale population structure of C. glabrata through genome sequencing of 80 clinical isolates obtained from six tertiary hospitals in Qatar and by comparing with global collections. Our fine-scale analyses revealed high genetic diversity within the Qatari population of C. glabrata and identified signatures of recombination, inbreeding and clonal expansion within and between hospitals, including evidence for nosocomial transmission among coronavirus disease 2019 (COVID-19) patients. In addition to signatures of recombination at the population level, both MATa and MATα alleles were detected in most hospitals, indicating the potential for sexual reproduction in clinical environments. Comparisons with global samples showed that the Qatari C. glabrata population was very similar to those from other parts of the world, consistent with the significant role of recent anthropogenic activities in shaping its population structure. Genome-wide association studies identified both known and novel genomic variants associated with reduced susceptibilities to fluconazole, 5-flucytosine and echinocandins. Together, our genomic analyses revealed the diversity, transmission patterns and antifungal drug resistance mechanisms of C. glabrata in Qatar as well as the relationships between Qatari isolates and those from other parts of the world.

Inanimate Surfaces as a Source of Hospital Infections Caused by Fungi, Bacteria and Viruses with Particular Emphasis on SARS-CoV-2

The carriers of nosocomial infections are the hands of medical personnel and inanimate surfaces. Both hands and surfaces may be contaminated as a result of contact with the patient, their body fluids, and touching contaminated surfaces in the patient’s surroundings. Visually clean inanimate surfaces are an important source of pathogens. Microorganisms have properties thanks to which they can survive in unfavorable conditions, from a few days to several months. Bacteria, viruses and fungi are able to transmit from inanimate surfaces to the skin of the patient and the medical staff. These pathogens include SARS-CoV-2, which can survive on various types of inanimate surfaces, being a potential source of infection. By following the recommendations related to washing and disinfecting hands and surfaces, and using appropriate washing and disinfecting agents with a broad biocidal spectrum, high material compatibility and the shortest duration of action, we contribute to breaking the chain of nosocomial infections.

A Brazilian Inter-Hospital Candidemia Outbreak Caused by Fluconazole-Resistant Candida parapsilosis in the COVID-19 Era

Horizontal transmission of fluconazole-resistant Candida parapsilosis (FRCP) through healthcare workers’ hands has contributed to the occurrence of candidemia outbreaks worldwide. Since the first COVID-19 case in Brazil was detected in early 2020, hospitals have reinforced hand hygiene and disinfection practices to minimize SARS-CoV-2 contamination. However, a Brazilian cardiology center, which shares ICU patients with a cancer center under a FRCP outbreak since 2019, reported an increased FRCP candidemia incidence in May 2020. Therefore, the purpose of this study was to investigate an inter-hospital candidemia outbreak caused by FRCP isolates during the first year of the COVID-19 pandemic in Brazil. C. parapsilosis bloodstream isolates obtained from the cancer (n = 35) and cardiology (n = 30) centers in 2020 were submitted to microsatellite genotyping and fluconazole susceptibility testing. The ERG11 gene of all isolates from the cardiology center was sequenced and compared to the corresponding sequences of the FRCP genotype responsible for the cancer center outbreak in 2019. Unprecedentedly, most of the FRCP isolates from the cardiology center presented the same genetic profile and Erg11-Y132F mutation detected in the strain that has been causing the persistent outbreak in the cancer center, highlighting the uninterrupted horizontal transmission of clonal isolates in our hospitals during the COVID-19 pandemic.

Candida glabrata Antifungal Resistance and Virulence Factors, a Perfect Pathogenic Combination

In recent years, a progressive increase in the incidence of invasive fungal infections (IFIs) caused by Candida glabrata has been observed. The objective of this literature review was to study the epidemiology, drug resistance, and virulence factors associated with the C. glabrata complex. For this purpose, a systematic review (January 2001-February 2021) was conducted on the PubMed, Scielo, and Cochrane search engines with the following terms: "C. glabrata complex (C. glabrata sensu stricto, C. nivariensis, C. bracarensis)" associated with "pathogenicity" or "epidemiology" or "antibiotics resistance" or "virulence factors" with language restrictions of English and Spanish. One hundred and ninety-nine articles were found during the search. Various mechanisms of drug resistance to azoles, polyenes, and echinocandins were found for the C. glabrata complex, depending on the geographical region. Among the mechanisms found are the overexpression of drug transporters, gene mutations that alter thermotolerance, the generation of hypervirulence due to increased adhesion factors, and modifications in vital enzymes that produce cell wall proteins that prevent the activity of drugs designed for its inhibition. In addition, it was observed that the C. glabrata complex has virulence factors such as the production of proteases, phospholipases, and hemolysins, and the formation of biofilms that allows the complex to evade the host immune response and generate fungal resistance. Because of this, the C. glabrata complex possesses a perfect pathogenetic combination for the invasion of the immunocompromised host.

Fungal carriage on healthcare workers' hands, clothing, stethoscopes and electronic devices during routine patient care: a study from a tertiary care center

Background

Invasive fungal infections are a constant threat to immunocompromised and critically ill patients. Healthcare workers caring for such patients act as conduits of transmission through their contaminated hands and belongings causing nosocomial infections. Although bacterial contamination of healthcare workers is known, our knowledge about fungal carriage is sparse. Among the fungi, candida species colonization of hands of healthcare workers is known however it would be interesting to know the type of fungal carriage on their inanimate belongings.

Aim

To study the prevalence and type of fungal carriage on healthcare workers hands, aprons/hospital scrubs, electronic devices, and stethoscopes.

Methods

Healthcare workers working in Medicine ward and ICU during November and December 2019 were sampled. Hand washes were collected in Brain Heart Infusion (BHI) broth with gentamycin. Direct impression smears on blood agar were taken from aprons/hospital scrubs. Electronic devices and stethoscopes were sampled using moist cotton swabs. Subculture and plating was done on Sabarouds Dextrose Agar (SDA). Yeasts were identified using Matrix Assisted Laser Desorption Ionisation Time of Flight (MALDI TOF) and moulds were identified using microscopy.

Findings

Out of 60 health care workers, 20 (33.3%) had fungal carriage. Aprons/hospital scrubs and hands were contaminated in 17 (28.3%) and 3 (5%) respectively. Aprons/hospital scrubs mainly constituted moulds belonging to species of Aspergillus. Hands were contaminated with Candida tropicalis, Candida parapsilosis and Candida auris. Electronic devices and stethoscopes had no fungal contamination.

Conclusions

Active fungal surveillance provides prevalent carriage rates and serve as a feedback to improve our disinfection and hand hygiene practices. It also aids in identification of potential source of hospital outbreaks.

Environmental Clonal Spread of Azole-Resistant Candida parapsilosis with Erg11-Y132F Mutation Causing a Large Candidemia Outbreak in a Brazilian Cancer Referral Center

Clonal outbreaks due to azole-resistant Candida parapsilosis (ARCP) isolates have been reported in numerous studies, but the environmental niche of such isolates has yet to be defined. Herein, we aimed to identify the environmental niche of ARCP isolates causing unremitting clonal outbreaks in an adult ICU from a Brazilian cancer referral center. C. parapsilosis sensu stricto isolates recovered from blood cultures, pericatheter skins, healthcare workers (HCW), and nosocomial surfaces were genotyped by multilocus microsatellite typing (MLMT). Antifungal susceptibility testing was performed by the EUCAST (European Committee for Antimicrobial Susceptibility Testing) broth microdilution reference method and ERG11 was sequenced to determine the azole resistance mechanism. Approximately 68% of isolates were fluconazole-resistant (76/112), including pericatheter skins (3/3, 100%), blood cultures (63/70, 90%), nosocomial surfaces (6/11, 54.5%), and HCW's hands (4/28, 14.2%). MLMT revealed five clusters: the major cluster contained 88.2% of ARCP isolates (67/76) collected from blood (57/70), bed (2/2), pericatheter skin (2/3), from carts (3/7), and HCW's hands (3/27). ARCP isolates were associated with a higher 30 day crude mortality rate (63.8%) than non-ARCP ones (20%, p = 0.008), and resisted two environmental decontamination attempts using quaternary ammonium. This study for the first time identified ARCP isolates harboring the Erg11-Y132F mutation from nosocomial surfaces and HCW's hands, which were genetically identical to ARCP blood isolates. Therefore, it is likely that persisting clonal outbreak due to ARCP isolates was fueled by environmental sources. The resistance of Y132F ARCP isolates to disinfectants, and their potential association with a high mortality rate, warrant vigilant source control using effective environmental decontamination.

Clinical and epidemiological aspects of Candidemia in eight medical centers in the state of Parana, Brazil: Parana Candidemia Network

Objectives

Candida spp. has been reported as one of the common agents of nosocomial bloodstream infections and is associated with a high mortality. Therefore, this study evaluated the clinical findings, local epidemiology, and microbiological aspects of candidemia in eight tertiary medical centers in the state of Parana, South of Brazil.

Methods

In this study, we reported 100 episodes of candidemia in patients admitted to eight different hospitals in five cities of the state of Parana, Brazil, using data collected locally (2016 and 2017) and tabulated online.

Results

The incidence was found to be 2.7 / 1000 patients / day and 1.2 / 1000 admissions. C. albicans was responsible for 49% of all candidemia episodes. Cancer and surgery were the two most common underlying conditions associated with candidemia. The mortality rate within 30 days was 48%, and removal of the central venous catheter (p = 0.029) as well as empirical or prophylactic exposure to antifungals were both related to improved survival (p = 0.033).

Conclusions

This study highlights the high burden and mortality rates of candidemia in hospitals from Parana as well as the need to enhance antifungal stewardship program in the enrolled medical centers.

The life and times of yeasts in traditional food fermentations

Yeasts are eukaryotic microorganisms which have a long history in the biotechnology of food production, as they have been used since centuries in bread-making or in the production of alcoholic beverages such as wines or beers. Relative to this importance, a lot of research has been devoted to the study of yeasts involved in making these important products. The role of yeasts in other fermentations in association with other microorganisms - mainly lactic acid bacteria - has been relatively less studied, and often it is not clear if yeasts occurring in such fermentations are contaminants with no role in the fermentation, spoilage microorganisms or whether they actually serve a technological or functional purpose. Some knowledge is available for yeasts used as starter cultures in fermented raw sausages or in the production of acid curd cheeses. This review aimed to summarize the current knowledge on the taxonomy, the presence and potential functional or technological roles of yeasts in traditional fermented plant, dairy, fish and meat fermentations.

Serial Systemic Candida albicans Infection Highlighted by Proteomics

Candida albicans is the major pathogen isolated from nosocomial bloodstream infections, leading to higher mortality rates. Thus, due to its clinical relevance, studies aiming to understand host–pathogen interactions in C. albicans infection are necessary. Therefore, we performed proteomic analysis using a murine model of serial systemic infection by C. albicans to evaluate possible changes in the protein profile of the pathogen over time. Firstly, we observed a reduction in the median survival time of infected animals with increasing passage number, suggesting a higher pathogenicity acquired during repeated infections. By LC-MS/MS, it was possible to obtain protein profiles from the wild-type strain (WT) and compare them to proteins extracted from Candida cells recovered from infected tissues during passages one, three, and four (P1, P3, and P4). We obtained 56, 29, and 97 proteins in P1, P3, P4, respectively, all varying in abundance. Regarding biological processes, the majority of proteins were related to carbohydrate metabolism, stress responses and amino acid metabolism. The proteins were also categorized according to their potential role in virulence traits, such as biofilm production, yeast-to-hyphae transition, phenotypic switching, proteins related to stress responses, and uncharacterized proteins. Therefore, serial infection in combination with proteomic approach enabled us to deepen the existing knowledge about host-pathogen interactions.

Promising New Antifungal Treatment Targeting Chorismate Synthase from Paracoccidioides brasiliensis

Paracoccidioidomycosis (PCM), caused by Paracoccidioides, is a systemic mycosis with granulomatous character and a restricted therapeutic arsenal. The aim of this work was to search for new alternatives to treat largely neglected tropical mycosis, such as PCM. In this context, the enzymes of the shikimate pathway constitute excellent drug targets for conferring selective toxicity because this pathway is absent in humans but essential for the fungus. In this work, we have used a homology model of the chorismate synthase (EC 4.2.3.5) from Paracoccidioides brasiliensis (PbCS) and performed a combination of virtual screening and molecular dynamics testing to identify new potential inhibitors. The best hit, CP1, successfully adhered to pharmacological criteria (adsorption, distribution, metabolism, excretion, and toxicity) and was therefore used in in vitro experiments. Here we demonstrate that CP1 binds with a dissociation constant of 64 ± 1 μM to recombinant chorismate synthase from P. brasiliensis and inhibits enzymatic activity, with a 50% inhibitory concentration (IC₅₀) of 47 ± 5 μM. As expected, CP1 showed no toxicity in three cell lines. On the other hand, CP1 reduced the fungal burden in lungs from treated mice, similar to itraconazole. In addition, histopathological analysis showed that animals treated with CP1 displayed less lung tissue infiltration, fewer yeast cells, and large areas with preserved architecture. Therefore, CP1 was able to control PCM in mice with a lower inflammatory response and is thus a promising candidate and lead structure for the development of drugs useful in PCM treatment.

Fungal infections in pediatric neurosurgery

INTRODUCTION

Invasive mycosis of the central nervous system represent a diverse group of diseases that have gradually emerged as not only opportunistic infections in patients with immune susceptibility due to congenital and acquired deficiency, immunomodulation, solid organ and stem cell transplantation, hematological malignancies, and chronic steroid use but also in selected risk populations such as low weight preterm infants, patients with shunted hydrocephalus and external ventricular drainages, skull base surgery, and head injury.

OBJECTIVES

The purpose of this review is to familiarize the pediatric neurosurgeon with the most common mycosis and their clinical scenarios which can be encountered in the clinical practice, with special emphasis on clinical, radiological, and laboratory diagnosis beyond classical microorganism cultures as well as options in medical and surgical treatment given the high incidence of morbidity and mortality associated with these challenging entities.

METHODS

We conducted an online database review (Ovid, PubMed) gathering relevant English language literature published in the last 20 years with special emphasis on recent breakthroughs in the diagnosis and treatment of invasive mycosis of the CNS as well as reported cases within the pediatric neurosurgical literature and their surgical management.

RESULTS

Fungal agents capable of invading the CNS can behave as aggressive entities with rapid progression manifesting as overwhelming meningoencephalitis with vascular compromise or can lead to space-occupying lesions with abscess formation which require prompt diagnosis by either laboratory identification of the components of these biological agents and their host response or by obtaining tissue specimens for microbiological identification which may not be straightforward due to prolonged culture time.

CONCLUSION

Following a high degree of suspicion with prompt initiation of antifungal agents and reversal of potential immunosuppressant therapies along with neurosurgical evacuation of intracranial collections or removal of infected hardware (CSF shunts) can lead to more optimistic outcomes of these complex clinical scenarios.