Antibiotic‐resistance profile in environmental bacteria isolated from penicillin production wastewater treatment plant and the receiving river

Abstract

SummaryThe antibiotic-resistance characteristics of bacterial strains in antibiotic production wastewater treatment plants (WWTP) that contain high concentrations of antibiotics are unknown, as are the environmental effects of the discharge of wastewater from such facilities. In this study, 417 strains were individually isolated from the effluent of a WWTP that treated penicillin G production wastewater, as well as from downstream and upstream areas of the receiving river. The minimum inhibition concentrations (MICs) of 18 antibiotics representing seven classes were then determined for each of these strains. Relatively high similarity in the bacterial composition existed between the wastewater and downstream river samples when compared with the upstream sample. High resistance ratios and MIC values were observed for almost all antibiotics in wastewater isolates, followed by strains from downstream river, of which the resistance ratios and levels were still significantly higher than those of upstream strains. The resistance ratios and levels also significantly differed among strains belonged to different species in the penicillin production wastewater effluent and downstream river. In both samples, the resistances to b-lactam antibiotics were more frequent, with much higher levels, than the other class antibiotics. Then five clinically important resistant genes mainly coding for extended-spectrum b-lactamases (ESBLs) were determined for all strains, only bla TEM-1 which did not belong to ESBL was detected in 17.3% and 11.0% of strains isolated from wastewater and downstream river respectively. Class I integrons were detected in 14% of wastewater isolates and 9.1% of downstream isolates, and primarily contained gene cassettes conferring resistance to aminoglycoside antibiotics. The unexpectedly high levels of multiple antibiotic resistance in strains from wastewater and downstream river were speculated to be mainly due to multidrug efflux systems.

Microbial Community Compositional Analysis for Series Reactors Treating High Level Antibiotic Wastewater

“…5,6 A reduction in bacterial number together with alterations in microbial populations were observed in a model sewage purification system when antibiotics were added in concentrations (2−5 mg L −1 ) that may occur in hospital wastewater. 7 According to our culturebased studies, 3,4 several bacterial groups such as Pseudomonas species (56%) and Stenotrophomonas maltophilia etc. (14%) have been linked with aquatic environments containing high concentrations of oxytetracycline (OTC), while those from a wastewater treatment plant (WWTP) receiving penicillin G (PEN) were Pseudomonas species (24%), Brachymonas denitrif icans (21%) and Psychrobacter pulmonis (20%).…”

Multidrug resistance in hydrocarbon-tolerant Gram-positive and Gram-negative bacteria

“…Previously, Li et al (2009) investigated the bacterial characteristics of a penicillin production wastewater treatment plant and the receiving river and demonstrated that high resistance prevalence and levels could be induced by long-term penicillin exposure. The resistance ratios and levels signifi cantly differed among strains belonging to different species (Li et al, 2009).…”

Microbial community functional structure in response to antibiotics in pharmaceutical wastewater treatment systems

“…Our previous studies have consistently shown that the high antibiotic levels in antibiotic production wastewater could lead to the occurrence of abundant antibiotic resistance in bacterial isolates from antibiotic production wastewater treatment systems (Li et al, 2009(Li et al, , 2010. So it is possible that bacteria possessing antibiotic resistance may play an important role for nutrient removal.…”