Evaluation of The Effect of Different Polyetheretherketone Materials on Biofilm Formation: An in vitro Study

Objective: The aim of this in vitro study was to investigate microorganism adhesion and biofilm formation between pure and ceramic-reinforced polyetheretherketone (PEEK) materials. Methods: A total of 72 rectangular (8 x 8 x 4 mm) samples were prepared from pure-PEEK without filler and PEEK (Ceramicreinforced PEEK - bio high-performance polymer) containing 20% nano-ceramic filler. A profilometer contact surface measurement device was used to assess the surface roughness of the samples. PEEK groups (36 pure PEEK, 36 Ceramic-reinforced PEEK) were divided into 4 sub-groups of 9 according to the microorganism strains. Staphylococcus aureus [American Type Culture Collection (ATCC 29213)], Acinetobacter baumannii (ATCC 19606), Enterococcus faecalis (ATCC 29212), and Candida albicans (ATCC 10231) standard strains were used for microbiological analysis. Blocks were added to 24-well microplates containing suspensions of microorganisms and were incubated at 37 °C for 72 hours. Microplates were read at a wavelength of 490 nm using crystal violet. Results: No significant difference was determined between the PEEK groups in terms of surface roughness. No significant differences in biofilm formation of S. aureus, A. baummanii, E. faecalis, and C. albicans strains were found between the PEEK groups (p>0.05). In the pure-PEEK, the highest adhesion was recorded in S. aureus (p<0.001), and the lowest adhesion in C. albicans (p<0.001). In the ceramic-reinforced PEEK group, S. aureus and A. baummanii adhesions were observed more than E. faecalis and C. Albicans (p<0.001). Conclusion: The results of this investigation demonstrated no significant differences in the biofilm formation of different strains between PEEK materials. This was a preliminary study to define the biological characteristics of ceramic-reinforced PEEK. There is a need for further comparative and clinical studies on this subject

The Prevalence of Cyclospora cayetanensis and Cryptosporidium spp. in Turkish patients infected with HIV-1

Opportunistic infections such as cryptosporidiosis and cyclosporiasis are commonly encountered in patients with acquired immunodeficiency syndrome (AIDS). We investigated the existence of opportunistic protozoans that significantly affect the quality of life in HIV-1 infected patients using conventional and molecular methods. The study group comprised 115 HIV-1 positive patients. In the identification of Cyclospora cayetanensis and Cryptosporidium, the formol-ether precipitation method was used and smears were evaluated in optical microscope by staining modified Ziehl-Neelsen (ZN). The primers and probes used for PCR were Heat shock protein 70 for C. cayetanensis and the oocysts wall protein for Cryptosporidium spp.. Cyclospora and Cryptosporidium spp. oocysts were detected in one and two patients, respectively, by staining, whereas we detected C. cayetanensis in three patients out of 115 (2.6%) by PCR, and Cryptosporidium spp. in a further three patients (2.6%). C. cayetensis was detected in patients with CD4 counts of 64 cells/mu m, 182 cells/mu m and 287 cells/mu m, respectively. Cryptosporidium spp. was detected in patients with CD4 counts of 176 cells/mu m, 241 cells/mu m and 669 cells/mu m. As conclusion, PCR method is faster and more sensitive than microscopic methods and to screen intestinal pathogens routinely in patients infected with HIV should not be neglected in developing countries like Turkey