Introduction. Among free-living amoebae that are widely distributed in nature only four genera/species are known as agents of human infections: Acanthamoeba spp., Naegleriafowleri, Balamuthia mandrillaris and Sappiniapedata. These amoebae are not well adapted to parasitism, and could exist...

A series of 1,6-bis(3-substituted-4,5-dihydro-1H-1,2,4-triazol-5-on-4- yl)hexanes (3a-g) were synthesized by the cyclization reaction of 1,6-bis(1- substituted-semicarbazide-4-yl)hexanes (2a-g) in alkaline medium. New derivatives (3a-c) were screened in vitro for their antiproliferative and anticancer activity in human tumor cell lines derived from breast and lung carcinoma cells. Compounds 3a (in concentration of 0.18 mM), 3b (in concentrations of 0.12 mM and 0.02 mM) and 3c (in concentrations of 0.23 mM and 0.11 mM) were found to be the most effective against lung cell line. The compound (3a) had the most antiproliferative effect on breast carcinoma cell line. Representative compounds were established and evaluated as antimicrobial agents. All tested derivatives showed MIC in range 1.87-7.5 (?g/mL). The compound (3b) was the most effective against C. albicans (MIC 1.87 ?g/mL).

Background: Determination of antibiotic resistance of opportunistic Corynebacterium colonizing the nose that cause infections and evaluation of the applicability of a simple method for detecting the most common constitutive-type resistance to macrolides, lincosamides and streptogramin B (MLSB). Methods: 70 isolates colonizing the nose and 70 clinical isolates of various infection sites were used and identified using APICoryne and 16S rRNA. Minimal inhibitory concentrations (MICs) were determined (Etest) for 12 antibiotics. MLSB was defined based on MIC, a simple method using two disks (erythromycin/clindamycin) and detection of the gene erm X (PCR). Results: There was a high percentage - in both groups at the same level - of strains with MLSB (88.5% colonizing the nose and 87.1% causing infections). Detection with the phenotypic method MLSB was confirmed genetically (erm X) in all cases. In both groups, a high percentage of resistance was found to trimethoprim/sulfamethoxazole (in both groups 71.4%), chloramphenicol (nose 44.2%/infections 37.1%), tetracycline (28 and 45.7%) and β-lactam antibiotics (18.5 and up to 32.8%). Conclusion: Differences in antibiotic resistance were found between strains colonizing the respiratory tract and various infections. Isolates from infections more frequently exhibited multidrug resistance. The possibility of using a simple method was confirmed for MLSB detection, which can be applied to determine drug resistance in routine microbiological diagnostics of infections caused by opportunistic Corynebacterium.

Corynebacterium pseudodiphtheriticum is commonly found in normal upper respiratory tract flora in humans. In certain conditions it can cause the opportunistic infections, especially in immunocompromised patients. In certain strains of Corynebacterium sp., the macrolide, lincosamide, and streptogramin B (MLS b ) resistance mechanism related to the presence of the erm(X) gene was discovered; hence, the need appeared for further investigation to confirm the existence of this gene among C. pseudodiphtheriticum . About 58 strains of C. pseudodiphtheriticum were used in this study. All strains were isolated from the nasal mucous membrane of patients with upper respiratory tract infection symptoms. Among the tested strains 52 were erythromycin resistant, and only 6 were erythromycin sensitive. The tested strains showed a very high percentage (89.7%) of the phenotype MLS b -constitutive resistance mechanism. The MLS b -inducible resistance among the tested strains was not observed. Association of the MLS b mechanism with resistance to chloramphenicol, trimethoprim/sulfamethoxazole and chloramphenicol, and trimethoprim/sulfamethoxazole was observed in 12.1%, 15.5%, and 44.8% tested strains, respectively. Among all isolates with the phenotype MLS b resistance, the presence of the erm(X) gene was confirmed by the polymerase chain reaction method. The results suggest that C. pseudodiphtheriticum with the MLS b -constitutive-type resistance can play a significant role in crossing this mechanism with other Corynebacterium sp., which colonize the nasal and throat mucous membrane.