Real-Time PCR based Rapid and Culture-Independent Detection of Citrobacter: ‘An Alarming State for Environment and Human Health’

The changing global scenario of environmental conditions and altered microbial community has severely deteriorated the quality of water which enforced an elevated health risks on human beings due to unavailability of safe and pristine water. Citrobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. It is an opportunistic pathogen formerly used as an indicator bacterium along with other fecal coliforms namely Escherichia coli, Klebsiella and Enterobacter, but is now known to cause several diseases in human beings. In present study we collected 135 samples from potable water and riverine-systems and confirmed the existence of Citrobacter using the conserved sequence of gnd (6-phosphogluconate dehydrogenate) gene with the application of SYBR green real-time PCR, which demonstrated extremely high specificity, fidelity and stringency in detection strategy. The Citrobacter counts in potable water were in the range of zero to 1.54 x104 ± 572.88 cfu/100ml. The Citrobacter levels in surface water were 2.18 x104 ±848, 1.54 x104 ±462, 3.53 x104 ±1299, 2.57 x104 ±912, 8.78 x103 ±201, 1.28 x104 ±370, CFU/100ml; associated with hydrophytes were 6.24 x104 ±1535, 8.42 x104 ±2711, 1.19 x105 ±4792, 1.12 x105 ±4177, 8.32 x104 ±2329, 8.08 x104 ±2149 CFU/10g and in the sediments the counts were 2.50 x104 ±647, 5.02 x104 ±1852, 3.26 x104 ±1186, 7.65 x104 ±2884, 1.50 x104 ±355, and 2.56 x104 ±737 CFU/10g at sampling site # 1, site # 2, site # 3, site # 4, site # 5 and site # 6, respectively. The present assay could be applied in the detection and regular monitoring of potable water and other environmental samples to check waterborne diseases and outbreaks caused by Citrobacter.