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Class 1 Integrons and the Antiseptic Resistance Gene (qacEΔ1) in Municipal and Swine Slaughterhouse Wastewater Treatment Plants and Wastewater-Associated Methicillin-Resistant Staphylococcus aureus.

Wan MT, Chou CC - Int J Environ Res Public Health (2015)

Bottom Line: Class 1 integrons are mobile gene elements (MGEs) containing qacEΔ1 that are resistant to quaternary ammonium compound (QAC) disinfectants.This study compared the abundances of class 1 integrons and antiseptic resistance genes in municipal (M) and swine slaughterhouse (S) wastewater treatment plants (WWTPs) and investigated the presence of class 1 integrons and antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) isolated from wastewater samples.The intI1 and qacEΔ1 genes were detected in all the wastewater samples, and they were more abundant in S-WWTP samples than in M-WWTP samples.

View Article: PubMed Central - PubMed

Affiliation: School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan. d99629002@ntu.edu.tw.

ABSTRACT
Class 1 integrons are mobile gene elements (MGEs) containing qacEΔ1 that are resistant to quaternary ammonium compound (QAC) disinfectants. This study compared the abundances of class 1 integrons and antiseptic resistance genes in municipal (M) and swine slaughterhouse (S) wastewater treatment plants (WWTPs) and investigated the presence of class 1 integrons and antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) isolated from wastewater samples. The abundances of intI1 and qacEΔ1 genes in 96 wastewater samples were quantified using real-time quantitative polymerase chain reaction (real-time qPCR), and 113 MRSA isolates recovered from the wastewater samples were detected class 1 integrons and linked antiseptic resistance genes (qacEΔ1), and minimum inhibitory concentrations (MICs) for QAC antiseptics. The intI1 and qacEΔ1 genes were detected in all the wastewater samples, and they were more abundant in S-WWTP samples than in M-WWTP samples. A higher percentage of MRSA isolates carried qacEΔ1 in MRSA from swine wastewater samples (62.8%) than in municipal MRSA (3.7%). All the MRSA isolates showed high MICs for antiseptic agents. This study provides important evidence regarding the abundances of intI1 and qacEΔ1 genes in municipal and swine slaughterhouse wastewater, and antiseptic-resistant MRSA strains were detected in swine slaughterhouse wastewater.

No MeSH data available.


Related in: MedlinePlus

(a) Schematic drawing of the process at the municipal wastewater treatment plant, M-WWTP, and (b) the swine slaughterhouse wastewater treatment plant, S-WWTP [21].
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ijerph-12-06249-f001: (a) Schematic drawing of the process at the municipal wastewater treatment plant, M-WWTP, and (b) the swine slaughterhouse wastewater treatment plant, S-WWTP [21].

Mentions: The municipal WWTP (M-WWTP) from which samples were taken for this study is one of the largest secondary treatment plants in Taiwan, receiving Taipei municipal wastewater with an average daily flow of 500,000 m3. The system is designed for primary treatment (i.e., the physical removal of solids), secondary treatment (i.e., biological processing), final clarification, and the chlorination treatment of outgoing water. Wastewater samples taken at sampling site M-A were the incoming influent wastewater at the M-WWTP; samples taken at sampling site M-B and M-C were wastewater before and after solid removal during primary treatment, the hydraulic retention time (HRT) between both is 1.1 h; samples taken at sampling site M–D were after secondary treatment for activated sludge process, the HRT is 4.8 h; samples M–E were taken from final clarification site, the HRT is 3.8 h, and samples M-F were the effluent water taken after chlorination treatment with HRT of 25.5 min. The S-WWTP from which samples were taken for this study is the treatment plant for the second largest swine auction market with pigs ready for slaughter in Taiwan, receiving wastewater with an average daily flow of 800 m3. The system is designed for primary treatment (solid/liquid separation), secondary treatment (activated sludge processing), final clarification, and the treatment of outgoing water (Figure 1). The incoming wastewater at the S-WWTP includes wastewater from the slaughterhouse of swine origin only. The processes completed at the S-WWTP include primary treatment (solid/liquid separation, sampling site S–A, HRT 1 h), activated sludge process I-III (sampling site S–B to S–D, HRT 6 h), final clarification (sampling site S–E, HRT 1 h), and the treatment of outgoing water (sampling site S–F). A total of 96 wastewater samples (24 from the M-WWTP and 72 from the S-WWTP) were collected between 2010 and 2011. Each sample consisted of 250 mL of wastewater placed in a sterile 500 mL Whirl-Pak bag and stored at 4 °C during transportation, which lasted less than 3 h [20].


Class 1 Integrons and the Antiseptic Resistance Gene (qacEΔ1) in Municipal and Swine Slaughterhouse Wastewater Treatment Plants and Wastewater-Associated Methicillin-Resistant Staphylococcus aureus.

Wan MT, Chou CC - Int J Environ Res Public Health (2015)

(a) Schematic drawing of the process at the municipal wastewater treatment plant, M-WWTP, and (b) the swine slaughterhouse wastewater treatment plant, S-WWTP [21].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4483699&req=5

ijerph-12-06249-f001: (a) Schematic drawing of the process at the municipal wastewater treatment plant, M-WWTP, and (b) the swine slaughterhouse wastewater treatment plant, S-WWTP [21].
Mentions: The municipal WWTP (M-WWTP) from which samples were taken for this study is one of the largest secondary treatment plants in Taiwan, receiving Taipei municipal wastewater with an average daily flow of 500,000 m3. The system is designed for primary treatment (i.e., the physical removal of solids), secondary treatment (i.e., biological processing), final clarification, and the chlorination treatment of outgoing water. Wastewater samples taken at sampling site M-A were the incoming influent wastewater at the M-WWTP; samples taken at sampling site M-B and M-C were wastewater before and after solid removal during primary treatment, the hydraulic retention time (HRT) between both is 1.1 h; samples taken at sampling site M–D were after secondary treatment for activated sludge process, the HRT is 4.8 h; samples M–E were taken from final clarification site, the HRT is 3.8 h, and samples M-F were the effluent water taken after chlorination treatment with HRT of 25.5 min. The S-WWTP from which samples were taken for this study is the treatment plant for the second largest swine auction market with pigs ready for slaughter in Taiwan, receiving wastewater with an average daily flow of 800 m3. The system is designed for primary treatment (solid/liquid separation), secondary treatment (activated sludge processing), final clarification, and the treatment of outgoing water (Figure 1). The incoming wastewater at the S-WWTP includes wastewater from the slaughterhouse of swine origin only. The processes completed at the S-WWTP include primary treatment (solid/liquid separation, sampling site S–A, HRT 1 h), activated sludge process I-III (sampling site S–B to S–D, HRT 6 h), final clarification (sampling site S–E, HRT 1 h), and the treatment of outgoing water (sampling site S–F). A total of 96 wastewater samples (24 from the M-WWTP and 72 from the S-WWTP) were collected between 2010 and 2011. Each sample consisted of 250 mL of wastewater placed in a sterile 500 mL Whirl-Pak bag and stored at 4 °C during transportation, which lasted less than 3 h [20].

Bottom Line: Class 1 integrons are mobile gene elements (MGEs) containing qacEΔ1 that are resistant to quaternary ammonium compound (QAC) disinfectants.This study compared the abundances of class 1 integrons and antiseptic resistance genes in municipal (M) and swine slaughterhouse (S) wastewater treatment plants (WWTPs) and investigated the presence of class 1 integrons and antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) isolated from wastewater samples.The intI1 and qacEΔ1 genes were detected in all the wastewater samples, and they were more abundant in S-WWTP samples than in M-WWTP samples.

View Article: PubMed Central - PubMed

Affiliation: School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan. d99629002@ntu.edu.tw.

ABSTRACT
Class 1 integrons are mobile gene elements (MGEs) containing qacEΔ1 that are resistant to quaternary ammonium compound (QAC) disinfectants. This study compared the abundances of class 1 integrons and antiseptic resistance genes in municipal (M) and swine slaughterhouse (S) wastewater treatment plants (WWTPs) and investigated the presence of class 1 integrons and antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) isolated from wastewater samples. The abundances of intI1 and qacEΔ1 genes in 96 wastewater samples were quantified using real-time quantitative polymerase chain reaction (real-time qPCR), and 113 MRSA isolates recovered from the wastewater samples were detected class 1 integrons and linked antiseptic resistance genes (qacEΔ1), and minimum inhibitory concentrations (MICs) for QAC antiseptics. The intI1 and qacEΔ1 genes were detected in all the wastewater samples, and they were more abundant in S-WWTP samples than in M-WWTP samples. A higher percentage of MRSA isolates carried qacEΔ1 in MRSA from swine wastewater samples (62.8%) than in municipal MRSA (3.7%). All the MRSA isolates showed high MICs for antiseptic agents. This study provides important evidence regarding the abundances of intI1 and qacEΔ1 genes in municipal and swine slaughterhouse wastewater, and antiseptic-resistant MRSA strains were detected in swine slaughterhouse wastewater.

No MeSH data available.


Related in: MedlinePlus