A Six-Month Survey of the Frequency of Extensively Drug-resistant Gram-Negative Bacteria by VITEK 2 System in 2020

 Increasing of resistant bacteria is a major concern globally. The emergence of XDR gram-negative bacteria is a more serious problem due to treatment limitations. This study aimed to evaluate the frequency of extensively drug-resistant (XDR) gram-negative bacterial isolates in different clinical samples from Payvand Clinical and Specialty Laboratory, Tehran, Iran, for 6 months by VITEK 2 system.

 During March 2020-September 2020, different clinical samples were collected from patients referred to Payvand Clinical and Specialty Laboratory. Bacterial identification and antimicrobial susceptibility test (AST) were performed applying an automated VITEK 2 system. The frequency of identified bacteria, their resistance to common antibiotics and also XDR bacteria were calculated and reported, respectively.

 Overall, 4125 urine specimens, 34 sputum samples, and 1 tracheal aspirate tube were submitted to Payvand Laboratory during 6 months. Of them, 486 urine, 32 sputum, and a tracheal aspirate tube samples were culture positive. Gram-negative isolated bacteria were included in this study. Based on AST, 63.3% of the isolated Klebsiella pneumoniae, 100% of Pseudomonas aeruginosa, and all Acinetobacter baumannii isolates were susceptible to amikacin and colistin. Totally, 31 XDR gram-negative bacteria, including: K. pneumonia (ssp. pneumonia (n=20), and ozaenae (n=2), Escherichia coli (n=3), P. aeruginosa (n=5), and A. baumannii (n=1) were identified from 18 urine samples, 12 sputum specimens, and a tracheal aspirate tube. 

 The rate of XDR bacteria was high in the investigated laboratory in this study. Therefore, accurate screening and antimicrobial stewardship is recommended in different medical centers of Iran.