Pseudo-outbreak of Lecanicillium and Acremonium species in orthopedic surgery patients

A case study: Lecanicillium infection detected in the human body

Lecanicillium dimorphum and Lecanicillium psalliotae are fungi that exist naturally in plants or insects, and are generally considered non-pathogenic to humans. However, in this case, we cultured Lecanicillium from the synovial fluid of a patient, and identified it through genome sequencing and sequence alignment as Lecanicillium dimorphum or Lecanicillium psalliotae. Due to the conservation of sequences, we can only identify the genus and not the species. There are very few reports on the human infection and pathogenicity of these two fungi, and this case also cannot completely prove that the pathogenic agent is this fungus. But this case also holds clinical significance, as the discovery of Lecanicillium in a human sample can alert the clinician to the presence of an uncommon mold with unclear clinical significance.

Intestinal mycobiome associated with diagnosis of inflammatory bowel disease based on tissue biopsies

Analysis of mycobiome from formalin-fixed, paraffin-embedded (FFPE) biopsies should preferentially detect only fungi which are actually present in the intestine wall, in contrast to stool samples, which are limited by the diet composition. Next generation sequencing provides the advantage of analysing many species from a single sample. Consequently, Canonical correspondence analysis divided fungal genera present in FFPE intestinal tissues into three well defined experimental groups (negative controls - NC, Crohn's disease - CD, ulcerative colitis - UC). Simultaneously, the analysis showed that particular fungal genera are associated with these experimental groups and several fungal genera occurred in all experimental groups equally. Our results also showed a noticeable increase of Ascomycota proportion from NC, through CD to UC. Fungal genera Malassezia, Cladosporium and Toninia occurred in all experimental groups assuming that they are common components of the intestinal mycobiome. Other fungal genera found only in the NC experimental group were non-pathogenic and might bring some benefits. In contrast, CD and UC samples were characterized by an accumulation of genera with inhibitive effects on growth of other fungal genera and the presence of opportunistic pathogens. Furthermore, a decrease in the fungal genus Malassezia in inflammatory tissues was observed; Specifically, the UC experimental group showed a connection between the presence of Candida and seven time's lower amounts of Malassezia (compared to amounts found in NC). The CD experimental group was characterized by the simultaneous presence of Engyodontium album with Lecanicillium, and indicate a possible pathogenic effect of Ramularia in disease development.

Rapid identification of fungi in culture-negative clinical blood and respiratory samples by DNA sequence analyses

Background

Clinical diagnoses of fungal infections often rely upon culture techniques followed by microscopic examination of positive cultures and histopathological specimens. Culturing of microorganisms is prone to false negatives, while microscopy methods can be complicated by atypical phenotypes and organisms that are morphologically indistinguishable in tissues. Delays in diagnoses (or the lack thereof) and inaccurate identification of infectious organisms contribute to increased morbidity and mortality in patients.

Methods

Two-hundred randomized, heterogeneous patient blood and respiratory samples that were culture-negative were tested using polymerase chain reaction (PCR) amplification of internal transcribed spacer regions of ribosomal RNA genes utilizing panfungal primers. Amplicons were sequenced, subjected to sequence similarity searches, and compared using phylogenetic analyses.

Results

Thirteen fungal sequences were detected in three whole-blood samples and nine respiratory samples. Bioinformatic analyses were performed which indicated the presence of multiple pathogens and potential pathogens.

Conclusions

The results from this pilot study demonstrate the utility of PCR assays and sequence analyses in clinical tests for fungi to facilitate rapid diagnosis and appropriate treatments to deal with the false negatives from culture results.

Healthcare-associated outbreaks due to Mucorales and other uncommon fungi

BACKGROUND

Healthcare-associated outbreaks of fungal infections, especially with uncommon and emerging fungi, have become more frequent in the past decade.

MATERIALS AND METHOD

Here, we reviewed the history and definition of healthcare-associated outbreaks of uncommon fungal infections and discussed the principles of investigating, containing and treatment of these outbreaks.

RESULTS

In case of these uncommon diseases, occurrence of two or more cases in a short period is considered as an outbreak. Contaminated medical devices and hospital environment are the major sources of these outbreaks. Care must be taken to differentiate a real infection from colonization or contamination. Defining and identifying cases, describing epidemiologic feature of cases, finding and controlling the source of the outbreak, treating patients, and managing asymptomatic exposed patients are main steps for outbreak elimination. These fungal outbreaks are not only difficult to detect but also hard to treat. Early initiation of appropriate antifungal therapy is strongly associated with improved outcomes in infected patients. Choice of antifungal drugs should be made based on spectrum, pharmacodynamic and pharmacokinetic characteristics and adverse effects of available drugs. Combination antifungal therapy and surgical intervention may be also helpful in selected cases.

CONCLUSIONS

A multidisciplinary approach and close collaboration between all key partners are necessary for successful control of fungal outbreaks.