Tetracycline Resistance Genes and Tetracycline Resistant Lactose-Fermenting Enterobacteriaceae in Activated Sludge of Sewage Treatment Plants

Abstract

Activated sludges were sampled from five sewage treatment plants (STPs) distributed in three geographically isolated areas, i.e., Hong Kong (Shatin, Stanley), Shanghai (Minhang) in China, and the bay area in California (Palo Alto and San Jose) of the United States. Among the tested 14 tetracycline resistance (tet) genes, nine genes encompassing efflux pumps (tetA, tetC, tetE, and tetG), ribosomal protection proteins (tetM, tetO, tetQ, and tetS), and enzymatic modification (tetX) were commonly detected in the STP sludge samples, whereas five genes encompassing efflux pumps [tetB, tetD, tetL, tetK, and tetA(P)] were not detected in any sludge sample. Additionally, 109 lactose-fermenting Enterobacteriaceae (LFE) strains were isolated from the activated sludge of the Shatin STP. Tetracycline-resistant (TR) LFE accounted for 32% of the total 109 LFE strains. The occurrence frequencies of tet genes among all TR-LEF strains varied from 0 to 91%, i.e., tetC (91%), tetA (46%), tetE (9%), tetG (6%), and tetD (6%). Finally, quantitative real-time polymerase chain reaction was used to quantify the change of tetC and tetA genes as the indicator of TR-LEF in the Shatin and Stanley STPs. The results showed that the concentrations of tetC and tetA genes in STP effluent ranged from 10(4) to 10(5) copies/mL, significantly lower than those in the influent by 3 orders of magnitude.

Antibiotic resistance in urban aquatic environments: can it be controlled?

“…Therefore, culture-independent methods are important complements to assess the occurrence of antibiotic resistance in the environment. Cultureindependent approaches, mainly real-time quantitative PCR (qPCR), have gained popularity (Auerbach et al 2007;Zhang et al 2009;LaPara et al 2011;Laht et al 2014;Narciso-da-Rocha et al 2014;Rodriguez-Mozaz et al 2015). These methods, although offering a good overview of the occurrence of antibiotic resistance in different types of environment (Vaz-Moreira et al 2014; Fig.…”

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

“…Inosine-S 3.33 Â 10 4 (1.08 Â 10 4 ) 1.78 Â 10 8 (2.73 Â 10 7 ) 1.87 Â 10 À4 (6.05 Â 10 À5 ) Ethanol-S 4.90 Â 10 4 (7.51 Â 10 3 ) 7.44 Â 10 7 (2.57 Â 10 6 ) 6.59 Â 10 À4 (1.10 Â 10 À4 ) w a t e r r e s e a r c h 4 7 ( 2 0 1 3 ) 6 2 9 8 e6 3 0 8 control systems (1.7 Â 10 À2 e3.1 Â 10 À2 ) and sewage treatment plants Zhang et al, 2009), showing that bacteria survived in the environment by possessing antibiotic resistance and the discharge of antibiotic resistance genes from the antibiotic production wastewater treatment systems is worthy of attention . Understanding the factors that influence microbial functional structure is an important goal in microbial ecology.…”

Tertiary-Treated Municipal Wastewater is a Significant Point Source of Antibiotic Resistance Genes into Duluth-Superior Harbor

“…[4][5][6][7][8] Antibiotic use in agriculture, for example, has been heavily scrutinized 9,10 and recently banned in the European Union. In contrast, the role of treated municipal wastewater has received relatively little attention as a reservoir of resistance, in spite of numerous reports suggesting that bacteria resistant to multiple antibiotics [11][12][13] and antibiotic resistance genes [14][15][16][17][18][19][20][21] are abundant in municipal wastewater.…”