BackgroundAntimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major concern worldwide. It has been recently feared that the blaTEM-1 gene is, via blaTEM-135, evolving into an extended-spectrum β-lactamase (ESBL), which could degrade all cephalosporins including ceftriaxone. The aims of the present study were to characterize the blaTEM genes, types of β-lactamase plasmids, the degradation of ampicillin by TEM-135 compared to TEM-1, and to perform molecular epidemiological typing of β-lactamase-producing N. gonorrhoeae strains internationally.Methodsβ-lactamase producing N. gonorrhoeae isolates (n = 139) cultured from 2000 to 2011 in 15 countries were examined using antibiograms, blaTEM gene sequencing, β-lactamase plasmid typing, and N. gonorrhoeae multiantigen sequence typing (NG-MAST). Furthermore, the blaTEM gene was sequenced in the first described Toronto plasmid (pJD7), one of the first Asian plasmids (pJD4) and African plasmids (pJD5) isolated in Canada. The degradation of ampicillin by TEM-135 compared to TEM-1 was examined using a MALDI-TOF MS hydrolysis assay.ResultsSix different blaTEM sequences were identified (among isolates with 125 different NG-MAST STs), i.e. blaTEM-1 (in 104 isolates), blaTEM-135 (in 30 isolates), and four novel blaTEM sequences (in 5 isolates). The blaTEM-1 allele was only found in the African and Asian plasmids, while all Rio/Toronto plasmids possessed the blaTEM-135 allele. Most interesting, the first described gonococcal Toronto plasmid (pJD7), identified in 1984, also possessed the highly conserved blaTEM-135 allele. The degradation of ampicillin by TEM-135 compared to TEM-1 was indistinguishable in the MALDI-TOF MS hydrolysis assay.ConclusionsblaTEM-135, encoding TEM-135, is predominantly and originally associated with the Rio/Toronto plasmid and prevalent among the β-lactamase producing gonococcal strains circulating globally. blaTEM-135 does not appear, as previously hypothesized, to have recently evolved due to some evolutionary selective pressure, for example, by the extensive use of extended-spectrum cephalosporins worldwide. On the contrary, the present study shows that blaTEM-135 existed in the Toronto plasmid from its discovery and that blaTEM-135 is highly conserved (not further evolved in the past >30 years). Nevertheless, international studies for monitoring the presence of different blaTEM alleles, the possible evolution of the blaTEM-135 allele, and the types of β-lactamase producing plasmids, remain imperative.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-454) contains supplementary material, which is available to authorized users.

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Different lifestyles, ranging from a saprophyte to a pathogen, have been reported in bacteria of one species. Here, we performed genome-wide survey of the ecological adaptation in four Burkholderia seminalis strains, distinguished by their origin as part of the saprophytic microbial community of soil or water but also including human and plant pathogens. The results indicated that each strain is separated from the others by increased fitness in medium simulating its original niche corresponding to the difference between strains in metabolic capacities. Furthermore, strain-specific metabolism and niche survival was generally linked with genomic variants and niche-dependent differential expression of the corresponding genes. In particular, the importance of iron, trehalose and D-arabitol utilization was highlighted by the involvement of DNA-methylation and horizontal gene transfer in niche-adapted regulation of the corresponding operons based on the integrated analysis of our multi-omics data. Overall, our results provided insights of niche-specific adaptation in bacteria. The ISME Journal (2016Journal ( ) 10, 2072Journal ( -2075 doi:10.1038/ismej.2015 published online 9 February 2016 Natural habitats, in particular soil and water, have been widely recognized as reservoirs for a variety of plant and human pathogenic bacteria (Rutala and Weber, 1997;Berg et al., 2005). A shift from a natural habitant to a host-associated pathogen lifestyle has been reported in a variety of bacteria (Morris et al., 2007;Mahenthiralingam et al., 2008;Vial et al., 2011;Lee et al., 2013). However, in most cases these natural habitants showed no virulence in plant and human hosts.This ecological phenomenon was understood in this study by examing the mechanism behind the niche adaptation of four B. seminalis strains DSM 23518 ( = LMG 24067 T ), 0901, S9 and R456, distinguished by their ecological origins as part of the saprophytic microbial community of soil or water but also including human and plant pathogens. This study clearly revealed the preference of each strain for specific niche environment based on both phenotypic characterization and growth in various niches. Indeed, the host plant apricot was specifically infected by strain 0901, while the cell number of strain S9 in water medium, strain R456 in soil extracted medium and strain DSM 23518 in CF medium is significantly higher (Po0.01, ANOVO test) than that of the other strains under the same conditions (Figure 1). Furthermore, adaptation of each strain to specific niche was found to be highly associated with its unique metabolic capacity, as shown by the Biolog test results (Table 1 and Supplementary Table S1). For example, infection of human by strain DSM 23518 was justified by its growth on 1.0% NaCl, similar to physiological saline. Utilization of D-trehalose and L-fucose by strain 0901 was justified by their existence in plant surfaces (Andersson et al., 2001), while utilization of D-mannitol by strain S9 may be due to its high abundance in algae that normally grow in w...

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