Campylobacteriosis, salmonellosis and avian chlamydiosis are zoonotic diseases in which birds have been suggested to play an important role as reservoirs. We have investigated the prevalence of Campylobacter and Salmonella spp. and Chlamydophila sp. in 107 freeliving birds belonging to 25 species from 13 families from Croatia in order to examine the natural infections caused by these agents. Campylobacter jejuni-like organisms were isolated from 2 of 107 free-living bird species examined (1.9%). Salmonella was isolated from 8 fresh fecal specimens from free-living bird species (7.4%). These isolates were identified as S. typhimurium in 4 (3.7%), and S. enteriditis in 4 (3.7%) free-living birds. These samples originated from feral pigeons (Columba livia domesticus; n=14; 28.6%), rook (Corvus frugilegus; n=13; 15.4%), buzzard (Buteo buteo; n=12; 16.7%), black-headed gull (Larus ridibundus; n=8; 12.5%) and tawny owl (Strix aluco; n=8; 12.5%). The presence of Chlamydophila sp. was not detected in the free-living birds examined during this study. Epidemiological aspects and possible significance of the examined birds as a source of infections for domestic animals and humans are discussed.

In this study, the low molecular weight lypophilic metabolites of C. albicans and C. dubliniensis strains produced in a synthetic medium with the addition of fetal calf serum were identified using LC/MS and MS/MS technique and quantified. All strains investigated produce a metabolite with a UV spectra maximum at 224 and 279 nm and minimum at 243 nm. Following comparison with ESI, MS/MS spectral data of a reference compound, the metabolite was identified as 3-indoleethanol (tryptophol). The concentration of extracellular tryptophol in the biosynthesis of C. albicans and C. dubliniensis ranged from 2.45 microg/mL to 191 microg/mL, respectively. Contrary to previously published data, gliotoxin or gliotoxin-like compounds were not detected, and all investigated C. albicans and C. dubliniensis strains have the same metabolite profile. Cytotoxic effects of tryptophol and 3-indolelactic acid (precursor of tryptophol biosynthesis) were cell-line-dependent. The EC50 of tryptophol ranged between 2 and 7 mM, with the EC50 of 3-indolelactic acid approximately double (between 4 and 8 mM). Tryptophol exhibited cell-type dependent cytotoxicity in relatively high concentrations, with domination of apoptosis.

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Thymus longicaulis C. Presl is a small aromatic perennial herb used as a traditional remedy for cold, flu and cough. Composition of the essential oil of T. longicaulis from Croatia and its in vitro antimicrobial activity against the most common respiratory pathogens were evaluated. The yield of essential oil obtained by hydrodistillation from aerial plant parts was 1.2%. According to the GC-MS analysis, a total of forty one compounds (99%) were identified. Thymol (46.3%), γ-terpinene (16.2%), thymyl methyl ether (11.4%), and p-cymene (9.4%) were the main components. Antimicrobial activity of the essential oil against six clinically isolated bacterial and yeast strains was determined using standard disc agar diffusion method and microdilution broth assay. The essential oil exhibited antimicrobial activity towards all tested respiratory pathogens. The most sensitive strains were Haemophilus influenzae and Streptococcus pneumoniae(MIC=0.78 mg/mL), while Staphylococcus aureus was the most resistant (MIC>25.00 mg/mL). Our results indicate that T. longicaulis essential oil could be effective against clinically relevant respiratory pathogens which have the ability to develop resistance to antimicrobial drugs.

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