Whole-genome sequencing and antimicrobial resistance in Brucella melitensis from a Norwegian perspective

Abstract

Brucellosis is a rarely encountered infection in Norway. The aim of this study was to explore all Brucella melitensis isolates collected in Norway from 1999 to 2016 in relation to origin of infection and antimicrobial resistance patterns. A total of 23 isolates were analysed by whole-genome sequencing and compared with selected sequences of B. melitensis available from NCBI. Additionally, SNP analysis in antibiotic resistance determining genes was performed. The majority belonged to the East Mediterranean clade (genotype II), while the remaining isolates belonged to the African clade (genotype III). These results indicate that human brucellosis in Norway is related to travels or migration from the Middle East, Asia or Africa, in accordance with results from Germany, Denmark and Sweden. Antibiotic susceptibility patterns were determined by broth microdilution method and/or gradient strip method. All isolates were susceptible for all tested antibiotics, except for rifampicin where phenotypical results indicated resistance or intermediate resistance in all isolates based on broth microdilution method, and in four isolates based on gradient strip testing. In contrast, screening of the rpoB gene did not reveal any mutations in the previously described rpoB “hot spot” regions related to rifampicin resistance, indicating overestimation of resistance based on phenotypical results.

The European Union One Health 2018 Zoonoses Report

“…Results from the national surveillance in France indicated that the most frequent at-risk countries visited by human cases reported during the period 2004-2013 were mainly Mediterranean countries (Algeria, Turkey, Portugal, Morocco and Tunisia) (Mailles et al, 2016). Investigation of brucellosis in Norwegian patients from 1999 to 2016 demonstrated that cases were linked to travelling and migration from the Middle East, Asia or Africa, which in accordance with results from other countries and reflects similar travelling and migration patterns in northern Europe (Johansen et al, 2018).…”

Identification, Genotyping and Antimicrobial Susceptibility Testing of Brucella spp. Isolated from Livestock in Egypt

“…However, the emergence of brucellae isolated from humans phenotypically resistant to ciprofloxacin, gentamycin, streptomycin, rifampicin and trimethoprim-sulfamethoxazole was reported in Egypt, Iran, Qatar, China, Norway and Malaysia [46,48,[63][64][65]. Phenotypically rifampicin resistant B. melitensis isolates were also reported from Norway in imported cases from the Middle East, Asia or Africa [45]. Probable rifampicin resistance was noted in 19% of a large collection of B. melitensis isolates from humans in Egypt between 1999 to 2007 [65].…”

“…The use of antimicrobial susceptibility testing is the solution for appropriate control and treatment of brucellosis [44,45]. Micro-dilution and/or gradient strip (E-test) methods are used to establish minimum inhibitory concentration (MIC) for antimicrobials [45,46].…”

“…The use of antimicrobial susceptibility testing is the solution for appropriate control and treatment of brucellosis [44,45]. Micro-dilution and/or gradient strip (E-test) methods are used to establish minimum inhibitory concentration (MIC) for antimicrobials [45,46]. PCR assays and the subsequent sequencing of genes associated with resistance are used to identify the genetic bases of resistance [47][48][49].…”

“…Resistance to commonly used antimicrobials is mediated by mutations of rpoB gene (rifampicin), gyrA, gyrB, parC, parE genes (quinolones), erm, mef, msr (macrolides) or the presence of tet genes (tetracyclines), mecA (beta-lactams) and floA (trimethoprim) [50]. Mutations in the rpoB and gyrA genes may occur naturally or can be induced in vitro [45,47,51,52].…”