Isolation and identification of free-living amoebae isolated from well water in Istanbul

Free-living amoebae (FLA) are ubiquitous protozoa commonly found in water and soil environments. FLA belonging to various genera, including Acanthamoeba, Balamuthia, Naegleria, and Vermamoeba, can cause opportunistic and non-opportunistic infections in humans and animals such as keratitis or meningoencephalitis. In addition, some of them serve as hosts for a large number of pathogenic bacteria, yeasts, and viruses. The purpose of the present study was to assess the prevalence and molecular characterization of FLA in well water samples in Istanbul. Ten well water samples were collected from the taps and the presence of FLA was monitored both by the culture and polymerase chain reaction methods. FLA were isolated in 8 out of the 10 samples (80%) included in this study. Morphological analysis and partial sequencing of the 18S rDNA revealed the presence of Acanthamoeba genotypes T3 and T4, and Vermamoeba vermiformis in the investigated well water samples. This study reports for the first time the detection of Acanthamoeba genotype T3 in well water samples in Istanbul. The presence of potentially pathogenic amoebae in habitats related to human activities supports the relevance of FLA as a potential public health concern

Identification of free-living amoebae isolated from tap water in Istanbul, Turkey

Free-living amoebae (FLA) are widely spread in the environment and also known to cause rare but often serious infections. The present work focuses on a local survey on FLA. It is essential to know the prevalence and distribution of these microorganisms in order to get infections caused by them under control. In this study, FLA isolated from domestic tap water samples from homes of contact lens wearers were identified by morphology and by 18S rRNA gene sequence analysis. Morphological analysis and partial sequencing of the 18S rDNA revealed the presence of Acanthamoeba genotype T4 and Vermamoeba vermiformis in the investigated tap water samples. Naegleria fowleri, Balamuthia mandrillaris, and Sappinia spp. were not detected during this study. It was shown that species of FLA known to cause eye infections in humans are widely distributed in tap water in Istanbul, Turkey. Contact lens wearers should be aware of the risk of contamination from tap water and strictly apply stringent contact lens hygiene. With this study, we established Acandrantoeba genotype T4 and Vermamoeba vermiformis as contaminants of tap water in Istanbul

UNNOTICED MICROORGANISMS IN DISINFECTION OF SWIMMING POOLS: FREE- LIVING AMOEBA

The presence of free-living amoebae (FLA) in swimming pools has become an issue of increasing concern in recent years on account of their pathogenicity and their capacity to host other microorganisms. Effective disinfection doses for neutralizing bacteria in swimming pools are specified in the guideline (15.11.2011) put out by the Turkish Ministry of Health; however, this guideline does include any information about FLA. This study aims, therefore, to investigate the effect of different concentrations (1, 3, 5 mg/L) and contact times (0, 30, 240 minutes) of NaClO against trophozoites of FLA isolated from swimming pool waters in Turkey. Experiments were conducted using the most probable number (MPN) method. Maximum log reductions were determined to be 1.764, 2.165, and 3.388 for 1, 3, and 5 mg/L of NaClO, respectively, at 240 minutes of contact time. A. castellanii (ATCC 50373) cysts showed little log reduction (0.017) against 5 mg/L of NaClO, which has a cytotoxic effect against 3T3 cells. Thus, we recommend that new disinfection strategies be developed to try to control the presence of FLA in swimming pools

Occurrence of Aerobic and Anaerobic Bacteria in the Consumer End of a Water Distribution System

In this study, mixed species biofilm formation including sulphate-reducing bacteria (SRB) on polypropylene surface and bacteriology of network water were investigated in a model water distribution system during a nine-month period. Water and biofilm samples were analyzed for the enumeration of aerobic heterotrophic bacteria (AHB), anaerobic heterotrophic bacteria (ANHB) and SRB. The number of live/dead bacteria was also analyzed by epifluorescence microscopy. In addition, extracellular polysaccharide substances (EPS) extraction, carbohydrate analysis and scanning electron microscope observation were performed. A biofilm with heterogeneous structure formed on the polypropylene surface of the model water distribution system. Live/dead staining data indicated that biofilm matured in the first month. It was observed that especially AHB entered into a viable but not culturable state because of the temperature decrease. It was also noted that temperature is an important environmental factor especially for planktonic SRB. The quantity of carbohydrate significantly decreased according to the temperature

The Effect of Short-Term Drying on Biofilm Formed in a Model Water Distribution System

In this study the effect of short-term drying on biofilm-related bacteria was investigated. Biofilm formation was encouraged to develop for nine months in a model water-distribution system. Biofilms were analyzed monthly for enumeration of aerobic and anaerobic heterotrophic bacteria, and sulphate reducing bacteria (SRB) after 6, 24, 48, and 72 hours of exposure to drying. The numbers of live and dead bacteria were directly analyzed by epifluorescence microscopy. In addition, extracellular polysaccharide substances (EPS) extraction, carbohydrate analysis, and scanning electron microscope (SEM) observation were performed. The formation of a brown-colored, thin biofilm layer was observed on the inner surface of polypropylene pipes at the end of the experimental study. SEM micrographs showed that ruptures occurred in the biofilm layer due to effects of drying. The counts of aerobic heterotrophic bacteria and SRB in dried biofilm samples decreased significantly after 6 and 48 hours, respectively. According to 5-cyano-2,3-ditolyl-tetrazolium chloride (CTC) staining results, bacteria can remain viable for up to 72 hours after exposure to drying. The significant increase in the amount of carbohydrate after 48 hours of exposure to drying indicates that bacteria produce EPS as a protective mechanism against drying stress

Acanthamoeba and other free-living amoebae in bat guano, an extreme habitat

Several representatives of the so-called free-living amoebae (FLA) are of medical relevance, not only as facultative pathogens but also as vehicles for pathogenic bacteria. Some FLA can survive and even grow under extreme environmental conditions. Bat guano is an exceptional habitat, the conditions becoming gradually more extreme with aging. In the current study, samples of bat guano of different ages from five caves in Slovenia were screened for the presence of FLA. FLA were isolated from almost all guano samples, including guano with a pH of 3.5. Only the two samples that had been drawn from > 20-year-old guano were negative for FLA. Generally, FLA diversity correlated to high concentrations of cultivable bacteria (similar to 10(8) CFU/g) and fungi (similar to 10(5) CFU/g). Interestingly, the absence of FLA in seasoned guanos was mirrored by the presence of dictyostelid slime moulds. The isolated amoebae were identified as belonging to the genera Acanthamoeba, Copromyxa, Naegleria, Sappinia, Tetramitus, Thecamoeba, Vahlkampfia, Vannella and Vermamoeba. To the best of our knowledge, this is the first study on the diversity of FLA in guano

EVALUATION OF ANTIBACTERIAL ACTIVITY OF SOME PLANT METHANOLIC EXTRACTS

The purpose of our study is to evaluate antibacterial acitivity of the methanolic extracts of 14 medicinal plants 8 of which are endemic species to Anatolia using the Disc diffusion assay. By disk diffusion assay, the antibacterial activity of plant extracts was evaluated by using the noncytotoxic concentrations for Vero cell line determined by MTT assay. The methanolic extracts were evaluated for antibacterial activity against 9 standart strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis ATCC 6633, Klebsiella pneumoniae ATCC 4352, Staphylococcus aureus ATCC 25923, Staphylococcus marcescens ATCC 13880, Escherichia faecalis ATTC 29212, Staphylococcus enteretidis ATCC 13076 and Proteus mirabilis ATCC 14153) and 11 environmental strains (S.aureus F1, F2, F3, Serratia marcescens F4, F5, F6, F7, P. aeruginosa F8, F9, P. spp. and Salmonella spp.). It was found that three plant extracts from the 14 plants studied had antibacterial activity. Olea europaea L. plant inhibited the growth of Staphylococcus aureus F1 environmental strain, Cotinus coggygria plant inhibited the growth of Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Enterococcus faecalis, Salmonella enteretidis, Proteus mirabilis standard strains and Staphylococcus aureus F1, Staphylococcus aureus F2, Staphylococcus aureus F3 environmental strains and Rosa damascena plant inhibited the growth of Staphylococcus aureus F3 environmental strain