Rapid detection of enterobacteria in wastewater treated by microalgal consortia using loop-mediated isothermal amplification (LAMP)

In the present study, nine Enterobacteriaceae species present in wastewater were isolated and identified, and loop-mediated isothermal amplification (LAMP) was developed for the detection of Enterobacteriaceae by designing primers based on the mcr-1, KPC, OXA-23, and VIM genes, which are recognized markers of antimicrobial resistance (AMR) transmission during microalgal bioremediation treatment. The developed assays successfully detected four strains positive for mcr-1 gene-asociated resistance (<i>Acinetobacter baylyi</i>, <i>Klebsiella pneumoniae</i>, <i>Morganella morganii</i>, and <i>Serratia liquefaciens</i>), three strains for KPC gene-associated resistance (<i>Acinetobacter</i> sp., <i>Escherichia coli</i> 15499, and <i>Morganella morganii</i>), seven strains for OXA-23 gene-associated resistance (<i>Acinetobacter baylyi</i>, <i>Enterobacter hormaechi</i>, <i>Enterobacter cloacae</i>, <i>Escherichia coli</i> 15922, <i>Escherichia coli</i> 51446, <i>Morganella morganii</i>, and <i>Serratia liquefaciens</i>), and three strains for resistance to the VIM gene-associated resistance (<i>Acinetobacter baylyi</i>, <i>Acinetobacter</i> sp., and <i>Enterobacter hormaechi</i>) from a single colony. A reduction in microbiological load of 93.6% was achieved at 15 colony-forming units (CFU) mL^-1, utilizing EMB agar and LAMP values of 0.142 ± 0.011 for the mcr-1 gene, 0.212 ± 0.02 for the KPC gene, 0.233 ± 0.006 for the OXA-23 gene, and 0.219 ± 0.035 for the VIM gene. Furthermore, bioremediation efficiency values of 71.6% and 75% for total nitrogen and phosphorus, respectively, were observed at 72 h of treatment in open pond microalgal remediation systems (MRS). This study demonstrated that the LAMP technique is faster and more sensitive than traditional detection methods, such as CFU, for Enterobacteriaceae. Consequently, this method may be considered for the detection of microbiological quality indicators within the water treatment industry.