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ColE1-like plasmids are widely used as expression vectors and as gene delivery vehicles. We have recently described a naturally occurring plasmid deletion phenomenon in the ColE1-type plasmid, pCI-neo, which leads to the detectable expression of an apparently promotorless kanamycin resistance gene. In the current work, we found that the expression of that aminoglycoside phosphotransferase (aph) gene is regulated by an RNAII preprimer promoter located within the plasmid ColE1 replication origin, as a consequence of the extension of the RNA II species for at least 1.5 kb, up to the aph gene. This mechanism is dependent on the nonformation and/or dissociation of the hybrid between plasmid DNA and RNA II preprimer transcript. This is the first in vivo description of RNA II transcription beyond ori in wild-type Escherichia coli strains and nonmutated RNAII plasmid sequences resulting in productive transcription of distant downstream genes. Our results raise questions about unwanted expression of genes from expression or cloning vectors of ColE1 type and highlight the importance of a more careful design of ColE1-derived plasmid vectors.

Human–wildlife coexistence may increase the potential risk of direct transmission of emergent or re-emergent zoonotic pathogens to humans. Intending to assess the occurrence of three important foodborne pathogens in wild animals of two wildlife conservation centers in Portugal, we investigated 132 fecal samples for the presence of Escherichia coli (Shiga toxin-producing E. coli (STEC) and non-STEC), Salmonella spp. and Campylobacter spp. A genotypic search for genes having virulence and antimicrobial resistance (AMR) was performed by means of PCR and Whole-Genome Sequencing (WGS) and phenotypic (serotyping and AMR profiles) characterization. Overall, 62 samples tested positive for at least one of these species: 27.3% for STEC, 11.4% for non-STEC, 3.0% for Salmonella spp. and 6.8% for Campylobacter spp. AMR was detected in four E. coli isolates and the only Campylobacter coli isolated in this study. WGS analysis revealed that 57.7% (30/52) of pathogenic E. coli integrated genetic clusters of highly closely related isolates (often involving different animal species), supporting the circulation and transmission of different pathogenic E. coli strains in the studied areas. These results support the idea that the health of humans, animals and ecosystems are interconnected, reinforcing the importance of a One Health approach to better monitor and control public health threats. [ABSTRACT FROM AUTHOR]

The expansion of mcr‐carrying bacteria is a well‐recognized public health problem. Measures to contain mcr spread have mainly been focused on the food–animal production sector. Nevertheless, the spread of MCR producers at the environmental interface particularly driven by the increasing population of gulls in coastal cities has been less explored. Occurrence of mcr‐carrying Escherichia coli in gull's colonies faeces on a Portuguese beach was screened over 7 months. Cultural, molecular and genomic approaches were used to characterize their diversity, mcr plasmids and adaptive features. Multidrug‐resistant mcr‐1‐carrying E. coli were detected for 3 consecutive months. Over time, multiple strains were recovered, including zoonotic‐related pathogenic E. coli clones (e.g. B2‐ST131‐H22, A‐ST10 and B1‐ST162). Diverse mcr‐1 genetic environments were mainly associated with ST2/ST4‐HI2 (ST10, ST131, ST162, ST354 and ST4204) but also IncI2 (ST12990) plasmids or in the chromosome (ST656). Whole‐genome sequencing revealed enrichment of these strains on antibiotic resistance, virulence and metal tolerance genes. Our results underscore gulls as important spreaders of high‐priority bacteria and genes that may affect the environment, food–animals and/or humans, potentially undermining One‐Health strategies to reduce colistin resistance. [ABSTRACT FROM AUTHOR]

The emergence of antimicrobial resistant infectious diseases remains a major threat to worldwide public health, in developed and in developing countries. Therefore, new antimicrobial agents acting by new mechanisms of action are urgently needed. As plants used in traditional medicine may help to overcome these problems, Justicia subsessilis, Platostoma rotundifolium, Pavetta ternifolia, Stomatanthes africanus, and Virectaria major (plants highly cited to be used against microbial infections in traditional Burundian medicine) were studied to assess their traditional use efficacy. We conducted a preliminary phytochemical screening of the extracts, as well as their direct and indirect (effect on antibiotic resistance) antibacterial activity on four bacterial strains (Staphylococcus sp. and Escherichia coli) by broth microdilution methods. All five medicinal plants investigated in this work were found to have direct antibacterial activity against all tested bacterial strains (minimum inhibitory concentration = 62.5-1000 μg/mL) that may support the use of these species in traditional Burundian medicine. Extracts (with no direct antibacterial activity), tested at 200 μg/mL, decreased the MIC values of β-lactams and aminoglycoside antibiotics by a factor of 2 to 64-fold. These interactions between plant extracts and antibiotics could open an avenue of research against antibiotic resistance. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]