Abstract <p><i>Pseudomonas&#xa0;</i>bacteria are prevalent in soil, water, and all living things. <i>Pseudomonas</i> aeruginosa bacterial infections are a type of illness that causes infections in many parts of the body, including the skin, lungs, and gastrointestinal tract, and weakens our immune system. This study presents a cesium lead bromide quantum dots (CsPbBr₃-QDs)-immobilized optical fiber-based surface plasmon resonance (SPR) biosensor for the rapid and sensitive detection of <i>Pseudomonas</i> bacteria. The proposed probe sensor comprises multilayers, silver (Ag), CsPbBr₃-QDs, an affinity layer, and an analyte. The performance of the sensor for <i>Pseudomonas</i> bacterial detection is analyzed using two methods: wavelength and angular interrogation. The thickness of Ag, CsPbBr₃-QDs and an affinity layers is optimized to 60, 8, and 3 nm, respectively, for better sensing performance. The test results indicate that the resonance parameters and sensitivity are directly proportional, while figure of merit (FOM) is inversely proportional to the analyte Refractive Index (RI). The wavelength interrogation method has a sensitivity of 1600 to 3305.6 nm/RIU, whereas the angular method has a sensitivity of 110 to 157.8 deg/RIU. On the other hand, FOM ranges from 26.7 to 32.0 RIU⁻¹ and 30.3 to 39.3 RIU⁻¹ for wavelength and angular interrogation methods, respectively. The maximum sensitivity and FOM of wavelength and angular interrogation methods are compared to three affinity layers: poly, toluene, and nicotine. The measured sensitivity ranges are 2400–3400 nm/RIU for poly, 2600–3300 nm/RIU for toluene and 2600–3400 nm/RIU for nicotine. A comparison of sensitivity and FOM with and without CsPbBr₃ QDs is performed. The wavelength and angular interrogation methods with CsPbBr₃-QDs in the proposed sensor produce 1.62- and 1.38-times higher sensitivity than the absence of CsPbBr₃-QDs, respectively.</p> Graphical Abstract <p></p>