  We proposed an extremely sensitive \textit{E. Coli} sensor based on a
hyperbolic metamaterial structure combining ultra-thin Ag-Al$_2$O$_3$ layers to
minimize metallic optical loss. The principle relied on detecting the change in
the resonance wavelength due to the interaction of bacteria with the
surrounding aqueous environment by utilizing the finite-difference time-domain
numerical technique. Our proposed hyperbolic metamaterial \textit{E. Coli}
sensor operated in the range from visible to near-infrared wavelengths
exhibiting strong bulk plasmon polaritons at the hyperbolic regime ($\lambda
\geq$ 460 nm). An anisotropic hyperbolic range was obtained theoretically by
solving the effective medium theory. An outstanding sensitivity of 9000 nm per
bacteria was achieved for a bulk plasmon-polariton mode. The hyperbolic
metamaterial was the origin of obtaining such extremely high sensitivity; no
bulk plasmon polaritons were found without hyperbolic metamaterial. We analyzed
the effect of different shapes in two-dimensional Ag differential grating on
sensing performance. Additionally, we compared the performance parameters of
our proposed \textit{E. Coli} sensor with recently demonstrated sensors. Our
proposed hyperbolic metamaterial structure has the potential as a highly
sensitive \textit{E. Coli} sensor operating in a wide range of wavelengths for
label-free detection.
