Extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing Enterobacteriaceae in water sources in Lebanon.

Extended-spectrum beta-lactamases (ESBLs) have been recurrently reported in both human and veterinary medicine, and carbapenemases have also emerged in these two sectors. Such resistance phenotypes were increasingly reported in the environment, which both receives and further disseminates multidrug-resistant (MDR) bacteria. Here, we report the high contamination of water samples (68.2%; 15/22) collected in estuaries in Lebanon. From these 15 contaminated sites, a total of 21 ESBL-producing (mostly harbouring the blaCTX-M-15 gene) and four carbapenemase-producing (two blaOXA-48 and two blaOXA-244) Enterobacteriaceae were recovered. ESBL contamination was also identified in water samples collected from rural wells and spring water, although at a lower frequency. Indeed, 1.9% (3/155) and 6.1% (7/115) of the wells and springs were contaminated, respectively, and all identified isolates were CTX-M-15-producing E. coli. Interestingly, sequence types (STs) previously associated both with animal and human reservoirs were detected (ST38, ST10 and ST131), suggesting a complex source of contamination. This situation is alarming since water drawn from wells or springs is directly intended for human consumption in Lebanon without any further treatment. Moreover, even though water from estuaries is not intended for human consumption, it is used to water animals and irrigate crops. Consequently, water contamination by ESBLs and carbapenemases in Lebanon is potentially a major risk to public health. Part of this work was presented at the 7th Symposium on Antimicrobial Resistance in Animals and the Environment (ARAE).