Prevalence, antibiotic susceptibility pattern and detection of antibiotic-resistant genes in Chryseobacterium indologenes isolated from the hospital environment

Abstract

Aims:The resistance rate of Chryseobacterium indologenes to commonly available antibiotics is very worrisome. As documented by SENTRY antimicrobial surveillance program, C. indologenes has different antibiotic resistance patterns. This study investigated the prevalence of C. indologenes in the hospital environment and their susceptibility pattern to commonly available antibiotics. Methodology and results: Chryseobacterium indologenes isolates were identified using DNA sequence-based identification method. Evaluation of resistant genes was done using specific primers. Fifty-two (52) isolates met the characteristics for the identification. Chryseobacterium indologenes' prevalence was 5.9%, 7.8% and 7.5% in hospitals 1, 2 and 3, respectively. The in vitro antibiotic susceptibility testing of C. indologenes isolates revealed that some isolates were multidrug-resistant. Some isolates were susceptible to levofloxacin (34.6%), ciprofloxacin (25%), ceftriaxone (19.2%) and gentamicin (13.5%). There was zero susceptibility to imipenem, cefuroxime, amikacin and ceftazidime. The 16s rRNA sequence of C. indologenes isolates showed 99.9% similarity compared with a highly similar sequence from the NCBI nucleotide database. Their evolutionary distances were in agreement with the phylogenetic placement of the 16S rDNA of the isolates, as all the isolates were revealed to be C. indologenes strain Sn6 with accession number KC683715. The resistant genes evaluation revealed that the isolates harbor SHV, TEM, QnrA, QnrS and APH (3')-IIIA genes, as indicated by amplification of those genes on agarose gel electrophoresis. Conclusion, significance and impact of study:The high prevalence of C. indologenes Sn6 and its high degree of resistance observed in this study represent a potential public health risk.