Detection of Clones B2-ST131-C2 and A-ST617 in Escherichia coli Producing Both CTX-M-15 and CTX-M-27 from Tunisian Community Patients.

During a two-month period (2017-2018), 336 urine samples positive for Escherichia coli were collected from Tunisian patients. Of the 336 samples, 266 were collected from community patients and 70 from hospital settings. In all, 15 ESBL producers were identified (8 and 7, respectively) and assigned to 13 pulsotypes, including four ESBL-producing E. coli (ESBL-E) with E1 and E2 profiles (2 isolates each) from community patients. The two strains E1 were identified as B2-ST131 subclade C2 and the two isolates E2, A-ST617. The four strains carrying both CTX-M-15 and CTX-M-27, exhibited the multireplicon IncFII/F1A/F1B with the same formula F31:A4:B1. Two isolates with patterns E3 and E4 (Dice coefficient, 78.7%) isolated from community and hospital settings of two geographic areas were assigned to the emerging ST131 C1-M27 subclade and contained the replicon F1:A-:B20. The remaining ESBL-E divided into different sequence types/associated CTX-M: 2 ST131-C2/CTX-M-15 and ST744/CTX-M-55, ST617/CTM-15, ST2973/CTX-M-55, ST6448/CTX-M-15, ST224/CTX-M-15, ST1431/CTX-M-15, and ST38/CTX-M-27, one isolate each. Our study reports for the first time the presence in the Tunisian community of two clones of E. coli, including the virulent clone ST131-C2 harboring both CTX-M-15 and CTX-M-27, and confirms the spread of the emergent clone ST131-C1-M-27, notably in community urinary tract infections.

MgrB Inactivation Is Responsible for Acquired Resistance to Colistin in Enterobacter hormaechei subsp. steigerwaltii.

Multidrug-resistant strains belonging to the Enterobacter cloacae complex (ECC) group, and especially those belonging to clusters C-III, C-IV, and C-VIII, have increasingly emerged as a leading cause of health care-associated infections, with colistin used as one of the last lines of treatment. However, colistin-resistant ECC strains have emerged. The aim of this study was to prove that MgrB, the negative regulator of the PhoP/PhoQ two-component regulatory system, is involved in colistin resistance in ECC of cluster C-VIII, formerly referred to as Enterobacter hormaechei subsp. steigerwaltii An in vitro mutant (Eh22-Mut) was selected from a clinical isolate of Eh22. The sequencing analysis of its mgrB gene showed the presence of one nucleotide deletion leading to the formation of a truncated protein of six instead of 47 amino acids. The wild-type mgrB gene from Eh22 and that of a clinical strain of Klebsiella pneumoniae used as controls were cloned, and the corresponding recombinant plasmids were used for complementation assays. The results showed a fully restored susceptibility to colistin and confirmed for the first time that mgrB gene expression plays a key role in acquired resistance to colistin in ECC strains.

Incomplete Hippocampal Inversion: A Comprehensive MRI Study of Over 2000 Subjects.

The incomplete-hippocampal-inversion (IHI), also known as malrotation, is an atypical anatomical pattern of the hippocampus, which has been reported in healthy subjects in different studies. However, extensive characterization of IHI in a large sample has not yet been performed. Furthermore, it is unclear whether IHI are restricted to the medial-temporal lobe or are associated with more extensive anatomical changes. Here, we studied the characteristics of IHI in a community-based sample of 2008 subjects of the IMAGEN database and their association with extra-hippocampal anatomical variations. The presence of IHI was assessed on T1-weighted anatomical magnetic resonance imaging (MRI) using visual criteria. We assessed the association of IHI with other anatomical changes throughout the brain using automatic morphometry of cortical sulci. We found that IHI were much more frequent in the left hippocampus (left: 17%, right: 6%, χ(2)-test, p < 10(-28)). Compared to subjects without IHI, subjects with IHI displayed morphological changes in several sulci located mainly in the limbic lobe. Our results demonstrate that IHI are a common left-sided phenomenon in normal subjects and that they are associated with morphological changes outside the medial temporal lobe.