[Show abstract][Hide abstract] ABSTRACT: qnrD is a plasmid mediated quinolone resistance gene from unknown origin, recently described in Enterobacteriaceae. It encodes a pentapeptide repeat protein 36-60% different from the other Qnr (A, B, C, S and VC). Since most qnrD-positive strains were described as strains belonging to Proteus or Providencia genera, we hypothesized that qnrD originated in Proteeae before disseminating to other enterobacterial species. We screened 317 strains of Proteeae for qnrD and its genetic support by PCR. For all the seven qnrD-positive strains (4 Proteus mirabilis, 1 Proteus vulgaris and 2 Providencia rettgeri) the gene was carried onto a small non-transmissible plasmid, contrarily to other qnr genes that are usually carried onto large multi-resistant plasmids. Nucleotide sequences of the qnrD-bearing plasmids were 96% identical. Plasmids contained 3 ORFs apart from qnrD and belonged to an undescribed incompatibility group. Only one plasmid, in P. vulgaris, was slightly different with a 1,568-bp insertion between qnrD and its promoter, leading to absence of quinolone resistance. We sought for similar plasmids in 15 reference strains of Proteeae, but which were tested negative for qnrD, and found a 48% identical plasmid (pVERM) in Providencia vermicola. In order to explain how qnrD could have been inserted into such native plasmid, we sought for gene mobilization structures. qnrD was found to be located within a mobile insertion cassette (mic) element which sequences are similar to one mic also found in pVERM. Our conclusions are that (i) the small non-transmissible qnrD-plasmids described here may result from the recombination between an as-yet-unknown progenitor of qnrD and pVERM, (ii) these plasmids are maintained in Proteeae being a qnrD reservoir (iii) the mic element may explain qnrD mobilization from non-transmissible plasmids to mobilizable or conjugative plasmids from other Enterobacteriaceae, (iv) they can recombined with larger multiresistant plasmids conjugated in Proteeae.
PLoS ONE 02/2014; 9(2):e87801. DOI:10.1371/journal.pone.0087801 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We previously described a pyrosequencing-based method able to guarantee detection of aac(6')-Ib-cr by characterizing precisely the single nucleotide polymorphisms leading to Trp102Arg and Asp179Tyr. By gaining in simplicity and cost-effectiveness, through the use of real-time PCR, we propose here a cutting-edge evolution of our existing pyrosequencing method.
[Show abstract][Hide abstract] ABSTRACT: In 2004 Weil et al reported the presence of CTX-M-15 in Salmonella enterica (10) and recently Ruppé et al. the carriage of CTX-M-15 producing isolates in children in a remote village in Senegal (8). ...
[Show abstract][Hide abstract] ABSTRACT: Two isolates of Enterobacter cloacae and 1 isolate of Acinetobacter baumannii showing a multidrug resistance phenotype including resistance to beta-lactams and fluoroquinolones were included in this study. By polymerase chain reaction amplification and sequencing, the 2 isolates of E. cloacae were found to produce QnrB and the A. baumannii isolate was found to produce QnrA. In addition, the 2 E. cloacae isolates were found to produce CTX-M-15.
[Show abstract][Hide abstract] ABSTRACT: To assess the frequency and diversity of extended spectrum beta-lactamases (ESBLs) in the Champagne-Ardenne region France, and to identify genetic elements associated with the bla(CTX-M) genes.
During 2004, all the non-duplicate isolates of Pseudomonas aeruginosa and Acinetobacter baumannii resistant to ceftazidime and of Enterobacteriaceae intermediate or resistant to ceftazidime and/or cefotaxime, screening samples excluded, were collected in 10 public hospitals and 3 private clinics. bla genes were sequenced and bla(CTX-M) environment characterized by PCR mapping.
In Enterobacteriaceae (138/21 861; 0.6%), ESBLs were predominantly TEM-24 (n = 52; 37.7%) and CTX-M-15 (n = 37; 26.8%). Three new enzymes were identified, CTX-M-61 (CTX-M-1 group), TEM- and SHV-type. A. baumannii (n = 5) produced VEB-1 and P. aeruginosa (n = 2) SHV-2a. ISEcp1 was detected in 22/27 strains, disrupted in 7 of them. The IS903-like element was downstream of bla(CTX-M-14) and bla(CTX-M-16). ISCR1 was found upstream of bla(CTX-M-2) and bla(CTX-M-9), and ISCR1 and bla(CTX-M-2) were located on a sul1-type class 1 integron. In comparison with 2001-02, ESBL distribution among Enterobacteriaceae showed an increase in CTX-M-type (44.9% vs 3.7% P < 10(-7)) due to Escherichia coli CTX-M-15 and to the almost total disappearance of TEM-3 (0.9% vs 51.2%). E. coli was the most frequent species (50.0% vs 5.1% in 1998) despite a similar prevalence to that in 1998 (0.5% vs 0.2%).
A careful detection of bla(CTX-M)-type spread to other species would help to anticipate clonal endemics such as those observed in Enterobacter aerogenes TEM-24.
[Show abstract][Hide abstract] ABSTRACT: For detecting extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in the hospital environment, sedimentation plates were placed in the rooms of two hospitals. Three environmental isolates, two Klebsiella pneumoniae, and one Escherichia coli resistant to extended-spectrum cephalosporins with a phenotype indicating CTX-M enzymes production (the minimum inhibitory concentration [MIC] of cefotaxime was higher than the MIC of ceftazidime) were recovered. By PCR and sequencing, the three isolates were found to produce CTX-M-15. The bla(CTX-M-15) genes in the three isolates were transferred by conjugation. One K. pneumoniae environmental isolate showed an identical and unique RAPD profile with two other K. pneumoniae clinical isolates recovered from urinary tract infection from patients hospitalized in two different wards of another hospital.
Microbial Drug Resistance 02/2007; 13(2):85-9. DOI:10.1089/mdr.2007.715 · 2.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We assessed the prevalence and phenotypic characteristics of extended-spectrum beta-lactamase producers among 365 clinical isolates of members of the family Enterobacteriaceae recovered from two hospitals in Béjaia, Algeria, between March 2004 and April 2005. Twenty-one strains were resistant to cefotaxime and/or ceftazidime. A double-disk synergy test yielded a positive result in five cases (three Escherichia coli, one Klebsiella pneumoniae and one Enterobacter cloacae). Using polymerase chain reaction and sequencing, the three E. coli isolates and the K. pneumoniae isolate were found to produce extended-spectrum beta-lactamase CTX-M-15 and the E. cloacae isolate produced CTX-M-3. The three CTX-M-15-producing E. coli isolates were not isolated in the same wards, although genotyping by randomly amplified polymorphic DNA analysis revealed that they were clonally related. The bla(CTX-M-15) genes were transferred from E. coli by conjugation, whilst conjugative transfer of bla(CTX-M) genes from K. pneumoniae and E. cloacae was not detectable.
International Journal of Antimicrobial Agents 06/2006; 27(5):397-402. DOI:10.1016/j.ijantimicag.2005.12.007 · 4.30 Impact Factor