Gregory Spanakos

Pseudomonas putida (P. putida) is a strictly aerobic, non-fermenting Gram-negative bacillus ubiquitously present in soil and aquatic environments. However, emerging evidence identifies P. putida as an increasingly important opportunistic pathogen responsible for severe nosocomial infections, particularly bacteremia and sepsis in immunocompromised and critically ill patients. Central Public Health Laboratory (CPHL) routinely receives carbapenem-resistant Pseudomonas spp isolates from the Greek hospitals. Five isolates (3 from 2023 and 2 from 2025) were sent to the laboratory as P. aeruginosa, P. putida and P. fluores. The isolates were subjected to phenotypical and molecular methods for the detection of the Metallo-Beta-Lactamases (MBL) genes [EDTA test, conventional PCR and Whole-genome sequencing (WGS) respectively]. The isolates were confirmed as VIM-producing isolates, while WGS reassigned them to four distinct species within the P. putida complex (P. soli, P. kurunegalensis, P. juntendi, and P. ceruminis). The isolates carried variations of the bla_VIM (VIM-2, VIM-4 and VIM-72) and were diverted into 5 different Sequence types (STs;3, 12, 13, 104, 125). VIM variants were distributed across phylogenetically distinct lineages, suggesting independent acquisition of events rather than clonal dissemination. Genome annotation and virulence screening confirmed the absence of the exotoxin A gene in all isolates. Although Pseudomonas putida isolates causing bacteremia have previously been reported in Greek hospitals, to our knowledge, this is the first study to assign the initially Pseudomonas spp isolates to new species of the P. putida complex and to characterize their genetic profile, at the level of resistance genes and phylogeny.

Plasmodium vivax malaria was common in Greece until the 1950s with epidemics involving thousands of cases every year. Greece was declared free of malaria by the World Health Organization in 1974. From 1974 to 2010, an average of 39 cases per year were reported, which were mainly imported. However, in 2009 and 2010 six and one autochthonous cases were reported culminating with a total of 40 autochthonous cases reported in 2011, of which 34 originated from a single region: Laconia of Southern Peloponnese. In this study the genotypic complexity of the P. vivax infections from the outbreak in Greece during 2011 is described, to elucidate the possible origin and spread of the disease.

Blastocystis is a prevalent enteric protozoan that infects a variety of vertebrates. Infection with Blastocystis in humans has been associated with abdominal pain, diarrhea, constipation, fatigue, skin rash, and other symptoms. Researchers using different methods and examining different patient groups have reported asymptomatic infection, acute symptomatic infection, and chronic symptomatic infection. The variation in accounts has lead to disagreements concerning the role of Blastocystis in human disease, and the importance of treating it. A better understanding of the number of species of Blastocystis that can infect humans, along with realization of the limitations of the existing clinical laboratory diagnostic techniques may account for much of the disagreement. The possibility that disagreement was caused by the emergence of particular pathogenic variants of Blastocystis is discussed, along with the potential role of Blastocystis infection in irritable bowel syndrome (IBS). Findings are discussed concerning the role of protease-activated receptor-2 in enteric disease which may account for the presence of abdominal pain and diffuse symptoms in Blastocystis infection, even in the absence of fever and endoscopic findings. The availability of better diagnostic techniques and treatments for Blastocystis infection may be of value in understanding chronic gastrointestinal illness of unknown etiology.

The aim of this study was to develop a simple, low-cost method for the detection and species differentiation of Leishmania directly from clinical samples, for routine use in a parasitology laboratory. A total of 87 samples was used, including 60 peripheral blood, seven bone marrow and 17 skin lesion material samples, derived from Greek patients with visceral or cutaneous leishmaniasis, and three reference strains. PCR was performed using primers designed to amplify the internal transcribed spacer 1 (ITS1) region of the rRNA gene. Identification of the Leishmania species studied was achieved by digestion with a single restriction endonuclease (RFLP), single-strand conformational polymorphism (SSCP) and DNA sequencing of the PCR-generated fragments. Typing identified all visceral and one cutaneous leishmaniasis strains as L. infantum, twelve of the cutaneous leishmaniasis strains as L. tropica and four as L. major. The described PCR method proved efficient for the detection of pathogenic Leishmania species in various clinical samples, most importantly in peripheral blood samples. Furthermore, PCR followed by a simple RFLP using a single restriction endonuclease was capable of identifying all Leishmania species commonly encountered in Greece.