Molecular Identification of Plasmid Mobile Colistin-Resistant Gene mcr-1 isolated from Klebsiella pneumoniae in Khartoum State, Sudan

Abstract

Colistin belongs to last resort antibiotic for the treatment of carbapenems resistant Gram-negative bacteria. Until recently, the resistant to colistin was restrictedly due to chromosomal mutations which cannot be transferred between organisms. However, identification of plasmid transfer mcr-1 colistin resistant gene is considered as a source of threat. The resistance of K.pneumoniae to antibiotics led to longer hospitalization, high cost, and increased mortality. It’s a descriptive cross sectional and hospital-based study, the main objective is to identify the presence of mcr-1 gene in K.pneumoniae using Polymerase chain reaction (PCR). The PCR was performed at research laboratory in Sudan University of Sciences and Technology, during the period from June to November, 2019. A total of (50) isolates were collected from Military hospital, Police University Hospital, Royal Care Hospital hospitals at Khartoum State. Laboratory tests such as colony growth characteristics and basic biochemical tests were performed to confirm identification of K.pneumoniae, antibiotic sensitivity test against colistin, DNA extraction and PCR tests for identification of K.pneumoniae and mcr-1 gene. Only 8(16%) isolates showed resistance against colistin, 42(84%) were susceptible to colistin. PCR results revealed that 2 (4%) out of (50) K.pneumoniae isolated from clinical specimens were positive for mcr-1 gene. This study confirm the presence of mcr-1 gene among clinical isolates of K.pneumoniae in Khartoum state, Sudan was 2 (4%). Out of (50) K.pneumoniae clinical isolates carried the mcr-1 gene, also the study revealed that the genotypic positive isolates of mcr-1 gene do not reflect phenotypic resistance to Colistin, and there were about 1(2%) mcr-1 gene positive K.pneumoniae isolates still susceptible to Colistin antibiotic by disk diffusion test.