Open AccessMetronidazole Resistance in Prevotella spp. and Description of a New nim Gene in Prevotella baroniae
Author(s) -
Corentine Alauzet,
F. Mory,
Corinne Teyssier,
H. Hallage,
JeanPhilippe Carlier,
G. Grollier,
Alain Lozniewski
Publication year - 2010
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.01003-09
Subject(s) - prevotella , metronidazole , microbiology and biotechnology , biology , 16s ribosomal rna , gene , gene sequence , antibiotics , bacteria , genetics
Nonduplicate clinical isolates ofPrevotella spp. recovered from patients hospitalized between 2003 and 2006 in two French tertiary-care teaching hospitals were investigated for their susceptibility to metronidazole and the presence ofnim genes. Of the 188 strains tested, 3 isolates displayed reduced susceptibility to metronidazole after 48 h of incubation, while 27 additional isolates exhibited heterogeneous resistance after prolonged incubation; all 30 of the isolates werenim negative. Among the remaining 158 isolates, 7nim -positive isolates were detected. All of these strains were identified asPrevotella baroniae by 16S rRNA gene sequence analysis and contained a newnim gene, namednimI , as determined by DNA sequence analysis. Chromosomal localization of this single-copy gene was demonstrated in all clinical isolates as well as in type strainP. baroniae DSM 16972 by using Southern hybridization. No known associated insertion sequence elements were detected upstream of thenimI gene in any of thenim -positive strains by PCR mapping. After prolonged exposure to metronidazole, stable resistant subpopulations could be selected innimI -positivePrevotella isolates (n = 6) as well as innim- negativePrevotella isolates (n = 6), irrespective of their initial susceptibility to this antibiotic. This study is the first description of a new nitroimidazole resistance gene inP. baroniae which seems to be silent and which might be intrinsic in this species. Moreover, our findings highlight the fact that high-level resistance to metronidazole may be easily induced in bothnim -positive andnim -negativePrevotella sp. strains.