Effect of povidone iodine, chlorhexidine digluconate and toyocamycin on amphizoic amoebic strains, infectious agents of Acanthamoeba keratitis – a growing threat to human health worldwide

Introduction Free-living amoebae, ubiquitous in outer environments, in predisposing circumstances may exist as parasites, infectious agents of Acanthamoeba keratitis. In recent decades, the vision-threatening corneal infection is a growing human health threat worldwide, including Poland. The applied therapy is often ineffective due to diagnostic mistakes, various pathogenicity of Acanthamoeba strains and high resistance of cysts to drugs; many agents with possible anti-amoebic activity are still being tested. In the presented study, selected chemicals are investigated in terms of their in vitro effect on corneal and environmental Acanthamoeba strains. Material and methods Samples of a corneal isolate from a patient with severe Acanthamoeba keratitis,of assessed on the basis of genotype associations of 18S rRNA and the type strain, Acanthamoeba castellanii Neff cultivated in bacteria-free condition, were exposed to povidone iodine, chlorhexidine digluconate or toyocamycin. In vitro population dynamics of the strains were monitored and compared to those of control cultures. Results All chemicals showed anti-amoebic effects with different degrees of effectiveness. Significant differences were observed in the in vitro population dynamics, and the morpho-physiological status of A. castellanii Neff T4 and corneal strains determined as A. polyphaga T4 genotype, exposed to povidone iodine or toyocamycin, in comparison with chlorhexidine taken as reference. Conclusions Time-dependent amoebstatic in vitro effects were demonstrated for all agents, in particular, the results of assays with povidone iodine are promising. No significant stimulation of encystation appeared; however, as cysticidal efficacy of chemicals is expected, complementary research is needed on different Acanthamoeba strains with modified agent concentrations and method application

Molecular identification of Trichomonas tenax in the oral environment of domesticated animals in Poland – potential effects of host diversity for human health

Introduction The protozoan Trichomonas tenax is considered to be a human specific flagellate of the oral cavity, found in humans with poor oral hygiene and advanced periodontal disease. Morphological variability and great similarity between species occurring in humans and animals, complicate the specific identification of trichomonads, using microscopic examination and other standard parasitological techniques. Objective The aim of the study was to search for and identify T. tenax in domesticated animals using molecular methods. The obtained data were assessed in terms of potential effects of a spread of the species deriving from the animals in the human environment. Material and methods 301 animals: 142 dogs, 57 cats and 102 horses, were examined in terms of their mouth status and occurrence of trichomonads. ITS1–5.8S rRNA-ITS2 region was amplified and sequenced. Results Finally, 7 dogs, 3 cats and 1 horse were diagnosed positive for T. tenax by PCR. In the oral cavity of 9 /11 animals, gingivitis and dental plaque accumulation were diagnosed. 9 /11 sequences of trichomonad isolates showed 100% identity with T. tenax sequence derived from the GenBank. The sequences of 2 isolates differed by substitutions. Conclusions It was proved that T. tenax , considered so far as a human specific parasite, can also inhabit the oral cavity of dog, cat and horse. To summarize, T. tenax was detected in the mouths of different domesticated animals, indicating that in Poland it can colonize a wider range of hosts than previously known. The owners of 3 dogs showed oral tissue inflammation of different intensity and were also positive for T. tenax ; therefore, oral trichomonosis spread from humans to domestic animals and conversely should be taken into consideration

Amoebicidal or amoebostatic influence of disinfectants used in health facilities and laboratories on corneal strains of Acanthamoeba

Different Acanthamoeba species are amphizoic organisms distributed in wide range of habitats in natural and man-made environments; they are also detected on surfaces of equipment and accessories in health facilities. Some strains of the amoebae are causative agents of the vision-threatening human disease Acanthamoeba keratitis, mainly reported in contact lens wearers. An exceptional high resistance of Acanthamoeba trophozoites and particularly cysts to chemicals, disinfectants and drugs is believed as influencing difficulty resulting in unsuccessful therapeutic management. As Acanthamoeba keratitis is the serious medical problem worldwide, different chemicals with possible activity against environmental and clinical Acanthamoeba strains are tested. In our study, selected disinfectants used in health care settings and laboratories were tested and their efficacy against the corneal strains Acanthamoeba castellanii and A. polyphaga , and environmental A. castellanii Neff strain was assessed. Comparative assessment of results of the assays show that, apart from amoebistatic effects, the disinfectants indicated expected cysticidal efficacy

In vivo confocal microscopy and in vitro culture techniques as tools for evaluation of severe Acanthamoeba keratitis incidents

Amphizoic amoebae belonging to the genus Acanthamoeba are known as etiological agents of sightthreatening Acanthamoeba keratitis. The leading risk factor for the development of this serious human disease is contact lens wearing which popularity increases worldwide, also in Poland. The disease with active epithelial inflammations, corneal ulcers, including loss of the visual acuity is a serious medical problem as an emerging threat for the public health related to improper contact lens hygiene. The treatment of the amoebic keratitis is difficult, often unsuccessful due to delayed proper diagnosis. The clinical picture of the disease, often with severe course is nonspecific, similar to that occurring in viral, fungal or bacterial keratitis, thus clinical symptoms alone are not sufficient to identify the causative agent of the amoebic infection. Early diagnosis is decisive for the suitable therapeutic management and the treatment efficacy. In our studies, several complicated, difficult to treat Acanthamoeba keratitis incidences pertaining Polish patients using contact lenses have been retrospectively analyzed in terms of the usefulness of non-invasive methods of in vivo confocal microscopy and in vitro culture techniques applied for diagnosis. Hyper-reflective double-walled spherical Acanthamoeba cysts, with a more reflective outer wall were detected in the epithelium and anterior layers of the corneal stroma. In vivo confocal microscopy, if available, may be a valuable, sensitive tool for diagnosis in late identified severe infections mainly with strong viability strains, however confoscan may offer limited value at lowintensity amoebic infections. The microscopic visualization of amoebae in slides prepared directly from corneal scraping and laboratory examinations of specimens from in vitro cultivated corneal isolates allow to confirm or verify results of in vivo examinations, furthermore to identify directly the pathogens and to clarify previous misdiagnoses

Identification of infectious microbiota from oral cavity environment of various population group patients as a preventive approach to human health risk factors

Introduction and objective. This study presents the results of comparative investigations aimed to determine microbiota that can occur in the oral environment in different human populations. The objective of the research was to identify pathogenic oral microbiota, the potential cause of health complications in patients of different population groups. Materials and method. The study included 95 patients requiring dental or surgical treatment; their oral cavity environment microbiota as risk factors of local and general infections were assessed. Results. In clinical assessment, differences occurred in oral cavity conditions between patients with malformations of the masticatory system, kidney allograft recipients and individuals without indications for surgical procedures. The presence of various pathogenic and opportunistic bacterial strains in oral cavities were revealed by direct microscopic and in vitro culture techniques. Conclusions. Colonization of oral cavities of patients requiring surgical treatment by the potentially pathogenic bacteria constitutes the threat of their spread, and development of general infections. Assessment of oral cavity infectious microbiota should be performed as a preventive measure against peri-surgical complications