Mikrobna obremenitev morske vode in peska na plaži med kopalno sezono | Microbial burden of seawater and beach sand during bathing season

Slovenian. Slovenija je ena od najbolj vodnatih evropskih držav, kjer je voda pomembna ne le za pitje, ampak tudi za različne rekreacijske dejavnosti, še posebej plavanje. Naravne rekreacijske morske vode so pomembno okolje, v katerem so kopalci izpostavljeni bakterijam, ki so odporne proti protimikrobnim učinkovinam ter številnim vrstam gliv. Poleg morske vode ljudje veliko časa preživijo tudi na obmorskih površinah (plaža s peskom) za katere se ne izvaja mikrobiološki monitoring. Da bi določili mikrobiološko obremenitev morske vode in peska na plaži, smo tekom kopalne sezone analizirali prisotnost bakterije Escherichia coli in oportuno patogenih gliv, ki se prenašajo preko človeka. E. coli je bila prisotna le v morski vodi znotraj dovoljenih meja čez celo kopalno sezono, z največjo frekvenco v avgustu. Poleg okoljskih sevov smo zaznali tudi seve iz skupine B2, seve s povečano zmožnostjo adhezije in sistemov za privzem železa ter seve z geni za odpornost proti antibiotikom iz skupin fluorokinolonov in beta-laktamov. Gliv v vodi tekom kopalne sezone z uporabljeno metodo nismo osamili. V nasprotju pa smo v pesku na plaži zasledili glive Candida parapsilosis, Geotrichum candidum in Trichosporon asahii, ki so del kožne mikrobiote ljudi. Število E. coli v morski vodi in gliv v pesku je naraščalo s številom kopalcev in je doseglo vrh v avgustovskem vzorcu. Glede na dobljene rezultate je E. coliprimeren parameter za spremljanje kakovosti morske vode medtem ko bi za spremljanje kakovosti peska na plaži lahko kot dodatni parameter uporabljali določene vrste gliv antropogenega izvora.

English. Slovenia is one of the most water-rich countries in Europe, where water is important not only as drinking water, but also for various recreational activities, especially swimming. Natural marine waters are an important environment where swimmers are exposed to resistant bacteria, and also fungi. In addition to seawater, people also spend a lot of time on sandy beaches, that are currently not microbiologically monitored. To determine the microbiological burden of seawater and beach sand during the bathing season, we analyzed the presence of bacteria Escherichia coli and opportunistic pathogenic fungi transmitted by humans. E. coli was present in seawater only within the permissible limits throughout the bathing season, with the highest incidence in August. Beside environmental strains, strains of the B2 phylogenetic group, strains with increased adhesion and iron uptake systems, and strains with genes for resistance to antibiotics from the fluoroquinolone and beta-lactam groups were also detected. With the method used, we were unable to isolate any fungi in the water during the bathing season. In contrary, we found human-transmitted fungal species Candida parapsilosis, Geotrichum candidum and Trichosporon asahii in the beach sand. The number of E. coli in the seawater and fungi in the sand increased with the number of bathers, both reaching a peak in the August sample. According to the results, E. coli is a suitable parameter for monitoring seawater quality, while certain types of human-related fungi could be used as an additional parameter for monitoring beach sand quality.