Genomic and phylogenetic analysis of a multidrug-resistant Burkholderia contaminans strain isolated from a patient with ocular infection

ABSTRACT: Objectives: The genus Burkholderia comprises rod-shaped, non-spore-forming, obligately aerobic Gram-negative bacteria that is found across diverse ecological niches. Burkholderia contaminans, an emerging pathogen associated with cystic fibrosis, is frequently isolated from contaminated medical devices in hospital settings. The aim of this study was to understand the genomic characteristics, antimicrobial resistance profile and virulence determinants of B. contaminans strain SBC01 isolated from the eye of a patient hit by a cow's tail. Methods: A hybrid sequence of isolate SBC01 was generated using Illumina HiSeq and Oxford Nanopore Technology platforms. Unicycler was used to assemble the hybrid genomic sequence. The draft genome was annotated using the NCBI Prokaryotic Genome Annotation Pipeline. Antimicrobial susceptibility testing was performed by VITEK®2. Antimicrobial resistance and virulence genes were identified using validated bioinformatics tools. Results: The assembled genome size is 8 841 722 bp with a G+C content of 66.33% distributed in 19 contigs. Strain SBC01 was found to possess several antimicrobial resistance and efflux pump genes. The isolate was susceptible to tetracyclines, meropenem and ceftazidime. Many genes encoding potential virulence factors were identified. Conclusion: Burkholderia contaminans SBC01 belonging to sequence type 482 (ST482) is a multidrug-resistant strain containing diverse antimicrobial resistance genes, revealing the risks associated with infections by new Burkholderia spp. The large G+C-rich genome has a myriad of virulence factors, highlighting its pathogenic potential. Thus, while providing insights into the antimicrobial resistance and virulence potential of this uncommon species, the present analysis will aid in understanding the evolution and speciation in the Burkholderia genus

Antimicrobial Resistance Studies Using Raman Spectroscopy on Clinically Relevant Bacterial Strains

There has been a steep rise in the emergence of antibiotic-resistant bacteria in the past few years. A timely diagnosis can help in initiating appropriate antibiotic therapy. However, conventional techniques for diagnosing antibiotic resistance are time-consuming and labor-intensive. Therefore, we investigated the potential of Raman spectroscopy as a rapid surveillance technology for tracking the emergence of antibiotic resistance. In this study, we used Raman spectroscopy to differentiate clinical isolates of antibiotic-resistant and -sensitive bacteria of Escherichia coli, Acinetobacter baumannii, and Enterobacter species. The spectra were collected with or without exposure to various antibiotics (ciprofloxacin, gentamicin, meropenem, and nitrofurantoin), each having a distinct mechanism of action. Ciprofloxacin- and meropenem-treated sensitive strains showed a decrease in the intensity of Raman bands associated with DNA (667, 724, 785, 1378, 1480, and 1575 cm–1) and proteins (640 and 1662 cm–1), coupled with an increase in the intensity of lipid bands (891, 960, and 1445 cm–1). Gentamicin- and nitrofurantoin-treated sensitive strains showed an increase in the intensity of nucleic acid bands (668, 724, 780, 810, 1378, 1480, and 1575 cm–1) while a decrease in the intensity of protein bands (640, 1003, 1606, and 1662 cm–1) and the lipid band (1445 cm–1). The Raman spectral changes observed in the antibiotic-resistant strains were opposite to that of antibiotic-sensitive strains. The Raman spectral data correlated well with the antimicrobial susceptibility test results. The Raman spectral dataset was used for partial least-squares (PLS) analysis to validate the biomarkers obtained from the univariate analysis. Overall, this study showcases the potential of Raman spectroscopy for detecting antibiotic-resistant and -sensitive bacteria

Comparative genomic analysis of a naturally competent Elizabethkingia anophelis isolated from an eye infection

Elizabethkingia anophelis has now emerged as an opportunistic human pathogen. However, its mechanisms of transmission remain unexplained. Comparative genomic (CG) analysis of E. anopheles endophthalmitis strain surprisingly found from an eye infection patient with twenty-five other E. anophelis genomes revealed its potential to participate in horizontal gene transfer. CG analysis revealed that the study isolate has an open pan genome and has undergone extensive gene rearrangements. We demonstrate that the strain is naturally competent, hitherto not reported in any members of Elizabethkingia. Presence of competence related genes, mobile genetic elements, Type IV, VI secretory systems and a unique virulence factor arylsulfatase suggests a different lineage of the strain. Deciphering the genome of E. anophelis having a reservoir of antibiotic resistance genes and virulence factors associated with diverse human infections may open up avenues to deal with the myriad of its human infections and devise strategies to combat the pathogen