Molecular detection of type III secretory toxins in Pseudomonas aeruginosa isolates

Pseudomonas aeruginosa has been known as a common unscrupulous pathogen that reasons cause nosocomial infections in patients with immunocompromise. Infection with multi-drug resistant Pseudomonas aeruginosa infection in many patients is a public health problem. The bacterium causes urinary tract infections, respiratory tract infections, skin inflammation and inflammation, soft tissue infections, bacteremia, bone and joint infections, gastrointestinal infections and various systemic infections, especially in patients with severe burns, cancer and AIDS, whose immune systems are suppressed. Among diverse virulence factors, the type III secretion system is known as a significant agent in virulence and development of antimicrobial resistance in P. aeruginosa. A total of 50 isolates of P. aeruginosa were gathered from burn wound and milk specimens. Documentation and antimicrobial susceptibility evidence were performed using the VITEK 2 system. Multiplex PCR was done to detect the secretion toxins-encoding genes. Out of 50 samples: 45/225 (20%) burn wound and 6/120 (5%) raw milk samples were found positive for P. aeruginosa. The multiplex PCR analysis of ExoT and ExoY genes showed that all P. aeruginosa 50 (100%) were positive. The occurrence of the ExoS and ExoU genes was 97.7% and 86.6% among clinical isolates while none of the raw milk isolates harbored the ExoU gene and 60% of them carried the ExoS gene. The results found 20 (40%) of isolates were multidrug resistance and the most effective antibiotics against clinical isolates were Ciprofloxacin and Meropenem. The aim of this study was to prevalence the exotoxin genes encoded type III secretion system and pattern of antimicrobial susceptibility of P. aeruginosa isolated from clinical and raw milk specimens.

Comparative evaluation of two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems for the identification of clinically significant yeasts

OBJECTIVES

To prospectively evaluate the performance of two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry systems (MALDI-TOF MS) for the identification of clinically significant yeast isolates compared to the VITEK 2 system.

METHODS

One hundred and eighty-eight consecutive yeast isolates were analyzed by Bruker Biotyper and VITEK MS. The results were compared with the conventional VITEK 2 yeast identification system. Discrepant results were resolved by direct sequencing of rDNA.

RESULTS

Accurate identification by VITEK 2, VITEK MS, and Bruker Biotyper MS was 94.1% (177/188), 93.0% (175/188), and 92.6% (174/188), respectively. Three isolates were not identified by VITEK MS, while nine Candida orthopsilosis were misidentified as Candida parapsilosis, as this species is not present in its database. Eleven isolates were not identified or were wrongly identified by Bruker Biotyper and although another 14 were correctly identified, the score was unreliable at <1.7.

CONCLUSION

The overall accuracy of rapid MALDI-TOF MS systems was essentially comparable to that of the conventional VITEK 2 yeast identification system. However, future expansion of the databases may further improve the outcome and accuracy of identification of yeast species.