Two Novel CMY-2-Type β-Lactamases Encountered in Clinical Escherichia Coli Isolates

BACKGROUND: Chromosomally encoded AmpC β-lactamases may be acquired by transmissible plasmids which consequently can disseminate into bacteria lacking or poorly expressing a chromosomal bla AmpC gene. Nowadays, these plasmid-mediated AmpC β-lactamases are found in different bacterial species, namely Enterobacteriaceae, which typically do not express these types of β-lactamase such as Klebsiella spp. or Escherichia coli. This study was performed to characterize two E. coli isolates collected in two different Portuguese hospitals, both carrying a novel CMY-2-type β-lactamase-encoding gene. FINDINGS: Both isolates, INSRA1169 and INSRA3413, and their respective transformants, were non-susceptible to amoxicillin, amoxicillin plus clavulanic acid, cephalothin, cefoxitin, ceftazidime and cefotaxime, but susceptible to cefepime and imipenem, and presented evidence of synergy between cloxacilin and cefoxitin and/or ceftazidime. The genetic characterization of both isolates revealed the presence of bla CMY-46 and bla CMY-50 genes, respectively, and the following three resistance-encoding regions: a Citrobacter freundii chromosome-type structure encompassing a blc-sugE-bla CMY-2-type -ampR platform; a sul1-type class 1 integron with two antibiotic resistance gene cassettes (dfrA1 and aadA1); and a truncated mercury resistance operon. CONCLUSIONS: This study describes two new bla CMY-2-type genes in E. coli isolates, located within a C. freundii-derived fragment, which may suggest their mobilization through mobile genetic elements. The presence of the three different resistance regions in these isolates, with diverse genetic determinants of resistance and mobile elements, may further contribute to the emergence and spread of these genes, both at a chromosomal or/and plasmid level.

Ophthalmoplegic Migraine and Infundibular Dilatation of a Cerebral Artery

Ophthalmoplegic migraine (OM) is a childhood disorder of uncertain etiology manifesting recurrent unilateral headache associated with a transitory oculomotor (usually IIIrd nerve) palsy. Recent publications emphasize the finding on MRI of contrast enhancement in the IIIrd nerve suggesting that OM may be a recurrent inflammatory neuropathy. We report the case of a 7-year-old boy with typical symptoms of this disorder. Angio MR and Angio CT revealed the presence of an infundibular dilatation of a perforating branch of the posterior cerebral artery adjacent to the symptomatic IIIrd nerve. We speculate that this and perhaps other cases of OM may have a different pathophysiology related to compression of the IIIrd nerve by an adjacent vascular structure that could activate the trigeminovascular system and produce migrainous pain.