Human Demodexmites (Demodex Folliculorumand Demodex Brevis) and Demodicosis

Anna Danai Panopoulou, Alexandra Ieronymaki, Stella Eugenia Chryssou
Laboratory of Biopathology, “Andrea Syggros” Hospital of cutaneous and venereal diseases, Athens

Demodex mites are obligatory human ectoparasites of the hair follicles and sebaceous glands, typically found on face and scalp. They are the largest and most complex organisms of the skin microflora. In humans only two species: Demodex folliculorum and Demodex brevis have been identified. Infestation with Demodex mites is common. In the adult population, these two Demodex species parasitize the normal skin with a prevalence of 20 – 100% and a usual density <5 mites/ cm2. Their potential as causative agents in the pathogenesis of human skin disorders causes continued speculation. Their interaction with the innate and adaptive immune system is unclear. Demodex mites have been found in skin lesions, but disease by Demodex has not been accepted as an entity. There are convincing reports of blepharitis, folliculitis, rosacea-like (rosaceiform) dermatitis, pityriasis folliculorum, Demodex facial dermatitis, perioral / periorbital dermatitis- like demodicosis, Demodex abscesses and scalp folliculitis (human demodectic alopecia) by Demodex, which respond to agents that reduce Demodex numbers. Some lesions similar to rosacea may also be caused by Demodex. All cutaneous diseases caused by Demodex mites are clubbed under the term demodicosis or demodicidosis. Dermatologists have not been able to reach agreement concerning the pathogenetic potential of the mites. The question whether they are mere commensals coincidentally found in diseased skin or a real cause of human skin disorders remains controversial. With growing interest in the microflora of the human skin and its relevance
to cutaneous health and disease, the role of this complex organism needs to be better understood.

Key words
Demodex mites, ectoparasites, demodicosis, skin disorder

The role of human gut microbiome in children with diffuse developmental disorder

Ioulia Patsiaoura, Georgia Gioula
Microbiology Department, School of Medicine, Faculty of Health Sciences Aristotle University of Thessaloniki

Human beings, like other mammals, live in a co-evolutionary association with huge quantities
of commensal microorganisms resident on the exposed and internal surfaces of their bodies.
The entirety of microorganisms in a particular habitat is termed microbiota or microflora, while
all these microorganisms (eukarya, archaea, bacteria and viruses) with their collective genomes
and the environment they live in and interact, constitute the term microbiome. 16S rRNA gene
sequencing has a major role in studying and analyzing of the human microbiome. Autism spectrum
disorders (ASD) are a set of complex neurodevelopmental disorders primarily characterized
by difficulties in social interaction, verbal and non-verbal communication and repetitive or stereotypic
behaviors. Autism represents the primary type of ASD. Emerging data have indicated a link
between gut microbiome and ASD, either as direct causality or as indirect consequences of atypical
patterns of feeding and nutrition. The human gut microbiome has the ability to “interfere”
in a series of functions of Central Nervous System (CNS). The gut receives regulatory signals from
the CNS and vice versa. The term gut-brain-axis thus describes an integrative physiology concept
that incorporates neural, endocrine, metabolic and immunological signals between the CNS and
the gastrointestinal system. The influence of microbiome on CNS manifested in both
normal and disease conditions. Τhere is a crucial link between gut microbiome and CNS maturation
under physiological state. The underlying nature of gastrointestinal dysfunction in ASD
and its relationship to etiology and ASD symptoms are areas for further research. The study of
human gut microbiome constitutes a “hopeful bacterial path” heading to amelioration of the
quality of life for children with ASD.

Key words
microbiome, autism, children, gut

Evaluation of a multiplex-PCR-based method for the rapid identification of dermatophytes in nail
specimens from patients with suspected onychomycosis

Georgia Vrioni1, Maria Vassiliki Kazani2, Constantinos Tsiamis1, Helen Papadogeorgakis2,
Athanassios Tsakris1
1Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Greece;
2Department of Microbiology, Andreas Sygros Hospital of Cutaneous and Venereal Diseases, Athens, Greece

Onychomycosis is a common nail disorder that can mimic other nail conditions. Fungal infection
of the nail requires a long term systemic antifungal treatment, which means that accurate diagnosis
is mandatory. The standard procedure for fungal detection in nails requires direct microscopy
and culture, but is still time consuming with high rates of false-negative results. Molecular assays
offer an alternative diagnostic process that might resolve problems of the standard methodology.
The aim of the current study was to evaluate a direct multiplex-PCR method in rapidly identifying
dermatophytes in nail specimens. Two-hundred fifty-two nail specimens of clinically suspected
onychomycosis cases were prospectively collected and equally divided for direct microscopy, culture
and PCR analysis. PCR was performed using the Dermatophyte PCR kit (Statens Serum Institut
Diagnostica, Denmark). The whole procedure was completed within 6 hours, including the extraction
stage. As many as 86 (34.1%) specimens were PCR-positive for dermatophytes, while 79
(31.3%) were positive by any of the conventional methods (55 by both microscopy and culture,
23 only by microscopic examination, and one only by culture). Thus, by using the PCR assay, the
number of positive specimens was increased by 7.1%. Furthermore, the percentage of those with
a species-specific identification (Τ. rubrumor dermatophytes) was increased by 11.9% Interestingly,
previous treatment uptake was not affecting PCR results since 12 specimens (4 negative with both
conventional methods and 8 positive only by microscopy) from patients previously treated with
antifungal regimens, were PCR-positive. The findings of this prospective study suggest that this
rapid and convenient multiplex-PCR method is a promising complementary diagnostic tool for
the management of patients with suspected onychomycosis.

Key words
Onychomycosis, multiplex PCR, molecular diagnosis

History of Greek Microbiology Laboratories: “Evangelismos” Hospital (1900-1940)

Constantinos Tsiamis, Georgia Vrioni, Kalliopi Theodoridou, Athanassios Tsakris
Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece

The history of the Microbiology Department of Evangelismos Hospital during the period 1924- 1940 is presented. The source of data was the archives of the Hospital (1924-1940). The Microbiology Department was established in 1900 but in 1931 was developed to a modern laboratory with serological, haematological and antirabies laboratory sections. The Microbiology Department has faced all the challenges of infectious diseases as malaria, tuberculosis and syphilis. According to the laboratory data a great number of diagnostic assays were performed, and the most common isolated microorganisms were Staphylococcus aureus, Salmonella typhi and Streptococcus pyogenes. For specific diagnoses Widal, Weil-Felix, Wasserman, Sachs-Georgi were used as serological tests, and Pirquet and Casoni, as skin tests. The contribution of the Microbiology Department to the diagnosis of severe infectious diseases as malaria, tuberculosis and syphilis was very important for the identification and management of the patients.

Key words
Evangelismos Hospital, history of Microbiology, infectious diseases, interwar period

Questions – Answers