The prevalence of antibiotic-resistant bacteria (ARB) in waters of the Lower Ballona Creek Watershed, Los Angeles County, California

Abstract

Screening for the prevalence of antibiotic-resistant bacteria (ARB) was done at the Ballona Creek and Wetlands, an urban-impacted wetland system in Los Angeles, California. The goals were (1) to assess the overall prevalence of ARB, and (2) compare differences in ARB abundance and the types of antibiotic resistance (AR) among the following sample types: lagoon water from Del Rey Lagoon, urban runoff from Ballona Creek, and water from the Ballona Wetlands (tidal water flooding in from the adjacent estuary, and ebbing out from the salt marsh). Antibiotic resistance distributions were analyzed using the Kolmogorov-Smirnov test to develop the cumulative frequency of bacteria having resistance of up to eight antibiotics. Distributions from the environmental water samples were compared to unchlorinated secondary effluent from the Hyperion Water Reclamation Plant that was used as comparator samples likely to have an abundance of ARB. As expected, densities of total and ARB were highest in secondary effluent, followed by urban runoff. Samples of water flooding into the wetlands showed similar results to urban runoff; however, a reduction in densities of total and ARB occurred in water ebbing out of the wetlands. During preliminary work to identify ARB species, several bacterial species of relevance to human illness (e.g., Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa, Aeromonas veronii, Enterobacter cancerogenus, Serratia marcescens, Pseudomonas stutzeri, and Staphylococcus intermedius) were isolated from sampled waters. If wetlands are a sink for ARB, construction and restoration of wetlands can help in the mediation of this human and environmental health concern.

High Prevalence of Cefotaxime Resistant Bacteria in Grazing Beef Cattle: A Cross Sectional Study

“…Besides farm management, other environmental factors can also affect the transmission of CRB. For example, runoff and flooding water can have high numbers of ARM, including multidrug-resistant E. coli (Blaak et al, 2015; Kawecki et al, 2017), and sewage water may be a reservoir of both ARM and plasmid mediated antibiotic resistant genes (Osinska et al, 2016). These ARM from water sources may be transmitted into cattle ranches during raining or flooding events.…”

Antimicrobial Resistance in the Environment

“…Similarly, the occurrence of AMR in bacteria isolated from an urban wetland and associated creek in California was also evaluated (Kawecki et al, 2017). A total of 22 water samples were collected including 19 from the watershed and 3 from the effluent of a local water reclamation plant.…”