Colistin susceptibility among multidrug resistant Gram-negative bacilli isolated from Tertiary hospital in Egypt
Novel Research in Microbiology Journal
Colistin is considered as the last resort for treatment of bacterial infections caused by carbapenem-resistant Gram-negative bacilli (GNB). Colistin resistance can increase due to the spread of plasmid-borne mcr-1 gene. This study aimed to determine colistin susceptibility and to detect the presence of mcr-1 gene in the clinical isolates of GNB recovered from different clinical samples collected from Ain Shams University Hospital, Cairo, Egypt. About thirty-five GNB isolates were recovered from
... were recovered from the different clinical samples that were collected during the period from February-April, 2019. These isolates were subjected to antibiotic susceptibility testing using disc diffusion assay, and Colistin susceptibility through the E-test. In addition, conventional Polymerase chain reaction (PCR) was carried out for detection of mcr-1 gene among the colistin GNB resistant isolates. Most of the GNB isolates (60 %) were recovered from blood samples. Klebsiella pneumoniae (K. pneumoniae) was the most common isolated bacterium; that was represented by 24 isolates (68%). Out of the 35 GNB, only five isolates (14.3 %) were resistant to colistin by E-test, with MIC >256 g/ ml. The mcr-1 gene was detected only in one Pseudomonas aeruginosa (P. aeruginosa) isolate. This study concluded the low frequency of mcr-1 gene among the current GNB isolates. However, a large scale study is recommended to detect colistin resistance among GNB. Keywords: Colistin susceptibility, mcr-1 gene, Multi-drug resistant GNB, PCR Behera, B.; Mathur, P.; Das, A. ; Kapil, A.; Gupta, B.; Bhoi, S. ; Behera, B.; Mathur, P.; Das, A.; Kapil, A.; Gupta, B.; Bhoi, S.; Farooque, K ; Sharma, V. and Misra, M.C. (2010). Evaluation of susceptibility testing methods for polymyxin. International Journal of Infectious Diseases. 14(7): e596-e601. CLSI. (Clinical and Laboratory Standards Institute) (2019). Clinical and Laboratory Standards Institute performance standards for antimicrobial susceptibility testing, 29 th Ed., El-Mokhtar, M.A.; Mandour, S.A. and Shahat, A.A. (2019). Colistin resistance among multidrugresistant E. coli isolated from Upper Egypt. Egyptian Journal of Medical Microbiology.. 28: 11-17. Elnahriry, S.S.; Khalifa, H.O.; Soliman, A.M.; Ahmed, A.M.; Hussein, A.M.; Shimamoto, T. and Shimamoto, T. (2016). Emergence of plasmidmediated colistin resistance gene mcr-1 in a clinical Escherichia coli isolate from Egypt. Antimicrobial Agents and Chemotherapy. 60(5): 3249-3250.