Extensively Drug-Resistant (XDR) Salmonella Typhi Outbreak by Waterborne Infection - Beijing Municipality, China, January-February 2022.

What is already known about this topic?: Typhoid fever remains a major public health problem in developing countries. Waterborne typhoid fever affects an estimated 27 million people worldwide each year. Decades of indiscriminate antibiotic usage has driven the emergence and spread of multidrug-resistant (MDR) and even extensively drug-resistant (XDR) Salmonella Typhi (S. Typhi) strains. What is added by this report?: By combining the epidemiological investigations, bacterial isolation from patients and household water, whole genome sequencing and drug resistance analysis, we identified a waterborne typhoid fever outbreak caused by XDR S. Typhi in Beijing municipality. This was the first report of the XDR S. Typhi triggered outbreak in Beijing, which was also rare in China. What are the implications for public health practice?: This report highlights the importance of ensuring access to affordable and safe drinking water, improved sanitation, and waste management systems for resource-constrained urban populations. Typhoid fever caused by XDR S. Typhi is still a severe public health threat.

Simple, Rapid and Sensitive Detection of Pseudomonas aeruginesa by Colorimetric Multiple Cross Displacement Amplification.

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.