Background Pseudomonas aeruginosa is considered as one of the most emerging threats in this century. Serious infections caused by this pathogen are often treated by carbapenems which are the last resource of antibiotics. Metallo-beta-lactamases (MBLs) production is one of the most important carbepenem resistance mechanisms and is usually related with nosocomial infections caused by P. aeruginosa . This study was aimed to determine the prevalence of MBL genes and distribution pattern of MBLs producing P. aeruginosa strains in Thailand. Materials and Methods Specific primers were designed to detect MBL genes including IMP-, VIM-, and NDM-type MBL genes. Multilocus sequence typing method was used to determine the dissemination pattern of carbapenem-resistance among multidrug-resistant (CR-MDR) P. aeruginosa . Results A total of 153 P. aeruginosa clinical isolates were characterized as CR-MDR. Among those, 31 P. aeruginosa clinical isolates (20.3%) presented metallo-beta-lactamase genes which could be divided into VIM-type (14 strains) and IMP-type (17 strains). bla IMP - 1 , bla IMP - 13 , bla IMP - 14a , and bla VIM - 2 genes were detected. Moreover, a novel IMP-type MBL, bla IMP - 65 was discovered and it was demonstrated to be the unique group of MBLs in Thailand. It was of interest that ST235 was the major ST type in Thailand followed by ST964 and ST111 and ST235 was detected in both MBL harboring and non-MBL harboring strains. Conclusion This study reported the dissemination of MBL gene including novel MBL, bla IMP-65 . This study was also demonstrated major ST of P. aeruginosa which was ST235, followed by ST964 and ST111. Moreover, it is also the first report on many P. aeruginosa STs in Thailand: ST273, ST292, ST621, ST1584, and ST1816 which emphasized the dissemination trait difference of MBLs harboring P. aeruginosa in Thailand.

In addition to their use as an additive to improve physical properties of solvent polymeric membranes, plasticizers have a considerable impact on the specificity and sensitivity of membrane-modified electrochemical sensors. In this work, we aim at the hybridization of two different plasticizers using the electropolymerization technique in the development of a cadmium(II)-selective electrochemical sensor based on screen-printed gold electrode along with cyclic voltammetric measurement. At this point, we first screen for the primary plasticizer yielding the highest signal using cyclic voltammetry followed by pairing it with the secondary plasticizers giving rise to the most sensitive current response. The results show that the hybridization of DOS and TOTM with 3:1 weight ratio (~137.7-μm-thick membrane) renders a signal that is >26% higher than that from the sensor plasticized by DOS per se in water. The solution of 0.1 mM hydrochloric acid (pH 4) is the optimal supporting electrolyte. In addition, hybrid plasticizers have adequate redox capacity to induce cadmium(II) transfer from bulk solution to the membrane/water interfaces. Conversion of voltammetric signals to semi-integral currents results in linearity with cadmium(II) concentration, indicating the irreversible cadmium(II) transfer to the membrane. The DOS:TOTM hybrid sensor also exhibits high sensitivity, with a limit of detection (LOD) and limit of quantitation (LOQ) of 95 ppb and 288 ppb, respectively, as well as greater specificity towards cadmium(II) than that obtained from the single plasticizer sensor. Furthermore, recovery rates of spiked cadmium(II) in water samples were higher than 97% using the hybrid plasticizer sensor. Unprecedentedly, our work reports that the hybridization of plasticizers serves as ion-to-electron transducer that can improve the sensor performance in cadmium(II) detection.

Streptomyces cavourensis BUU135 is a bacterial species isolated from the soil of a tropical fruit farm. The genome of S. cavourensis BUU135 comprises a gene encoding nebramycin 5′ synthase, which produces nebramycin 5′ by catalyzing the O-carbamoylation reaction of tobramycin. The newly sequenced 7.66-Mb draft genome of S. cavourensis BUU135 may contribute to the discovery of novel natural products derived from this organism.