Pseudomonas aeruginosa (P. aeruginosa) is a major opportunistic pathogen in hospital-acquired infections. Thus, early diagnosis is the best strategy for fighting against these infections. In this report, we incorporated multiple cross displacement amplification (MCDA) combined with the malachite green (MG) for rapid, sensitive, specific and visual detection of P. aeruginosa by targeting the oprl gene. The MCDA-MG assay was conducted at 67°C for only 40 min during the amplification stage, and then products were directly detected by using colorimetric indicators (MG), eliminating the use of an electrophoresis instrument or amplicon analysis equipment. The entire process, including specimen processing (35 min), amplification (40 min) and detection (5 min), can be finished within 80 min. All 30 non-P. aeruginosa strains tested negative, indicating the high specificity of the MCDA primers. The analytical sensitivity of the MCDA-MG assay was 100 fg of genomic templates per reaction in pure culture, which was in complete accordance with MCDA by gel electrophoresis and real-time turbidity. The assay was also successfully applied to detecting P. aeruginosa in stool samples. Therefore, the rapidity, simplicity, and nearly equipment-free platform of the MCDA-MG technique make it possible for clinical diagnosis, and more.
Keywords: Pseudomonas aeruginosa; malachite green; multiple cross displacement amplification; multiple cross displacement amplification combined with the malachite green.