1.Drug resistance, distribution and homology analysis of type Ⅲ secretion system virulence genes of Pseudomonas aeruginosa isolated from barreled drinking water in Hainan Province
YANG Suishan ; ZHU Meng ; CHANG Xiuting ; LUO Xiaoju ; KOU Lidan ; WANG Bin ; XIE Zuorong
China Tropical Medicine 2023;23(12):1307-
Objective To provide a data foundation not only for food safety supervision and pollution source tracing, but also for the clinical treatment of drug-resistant bacteria in barreled drinking water, the drug resistance and type Ⅲ secretion system (T3SS) virulence genes carriage of Pseudomonas aeruginosa detected in barreled drinking water in Hainan Province were investigated, and the correlative relationship between strain ribosomal subtypes and virulence genes were then discussed. Methods The drug resistance of the isolated 55 strains of Pseudomonas aeruginosa was confirmed by using VITEK 2 Compact automatic microbial drug sensitivity system, and the T3SS virulence genes ExoU, ExoS, ExoT and ExoY were amplified by PCR, bacterial strain subtypes and homology were analyzed by the RiboPrinter automatic microbial gene fingerprint identification system. Results The drug sensitivity results showed that Pseudomonas aeruginosa isolated from barreled water had relatively low drug resistance, though one strain of multidrug-resistant Pseudomonas aeruginosa was discovered, resistant to imipenem, ciprofloxacin and cefepime. The distribution of T3SS virulence genes showed four genotypic combinations: ExoT+/ExoY+/ExoS+/ExoU- (45.45%, 25/55), ExoT+/ExoY+/ExoS-/ExoU+ (34.55%, 19/55), ExoT+/ExoY-/ExoS-/ExoU+(18.18%, 10/55), ExoT+/ExoY+/ExoS+/ExoU+ (1.82%, 1/55). Ribosomal typing results showed that the Pseudomonas aeruginosa strains were divided into six subtypes, the numbers of each subtype accounted for 24 (43.64%), 1 (1.82%), 25 (45.45%), 1 (1.82%), 3 (5.45%) and 1 (1.82%) respectively, with subtype Ⅰ and subtype Ⅲ being dominant. The main T3SS genotypes of the top two subtype I and subtype III were ExoT+/ExoY+/ExoS-/ExoU+ (16/24, 66.67%) and ExoT+/ExoY+/ExoS+/ExoU- (22/25, 88%). Conclusions The T3SS secretion system exhibits the characteristics of multiple virulence genes' coordinated expression, and there is a certain correlation between subtypes of bacterial strains and virulence genotypesThe exploration of the relationship between them provides guidance for tracing the source of Pseudomonas aeruginosa contamination, production control, clinical treatment in barrelled drinking water, and preliminarily establishes the initial data of local Pseudomonas aeruginosa strains in barrelled drinking water as well the related drug sensitivity data in Hainan.