Point mutations in the glycosyltransferase domain of the pbp1a gene in amoxicillin-resistant Helicobacter pylori isolates.

INTRODUCTION: Helicobacter pylori (H. pylori) eradication treatment includes a proton pump inhibitor and two antibiotics: amoxicillin and clarithromycin. The goal of that treatment is to eradicate the infection in at least 90% of the patients. Failure to eradicate the infection can have multiple causes, among which is the presence of point mutations in the antimicrobial target genes. OBJECTIVE: To characterize the mutations present in the pbp1a gene and their possible association with resistance to amoxicillin in vitro. METHODOLOGY: Susceptibility to amoxicillin was evaluated in 147 isolates of H. pylori from the Colombian municipality of Túquerres. PCR amplification and sequencing of the glycosyltransferase domain of the pbp1a gene were carried out on Túquerres isolates, and the association between mutations and resistance was evaluated. RESULTS: A total of 5.4% (8/147) Túquerres isolates were resistant to amoxicillin in vitro. PCR amplification of the glycosyltransferase domain of the pbp1A gene was performed on 87.5% of the amoxicillin-resistant isolates in vitro, and in the DNA sequencing analysis, a total of 2 changes of amino acids from 3 DNA mutations that encoded the PBP1A-1 protein were observed. CONCLUSION: The present study is the first report on pbp1a gene mutations in H. pylori isolates coming from a population in Túquerres. Mutations that have not been reported in previous studies were found.

Sensitivity, specificity, and surgical impact of somatosensory evoked potentials in descending aorta surgery.

BACKGROUND: We evaluate the efficiency of multilevel somatosensory evoked potential (SEP) monitoring for intraoperative re-establishment of blood flow to the spinal cord in 63 patients undergoing descending aorta repair. METHODS: The presence of critical vessels in a cross-clamped aortic segment was ascertained by a 15 minute SEP observation period while the segment between the clamps was vented to drain out the collateral flow. RESULTS: SEPs influenced the surgical strategy in 17 cases (27%): use of the Biomedicus in 1 traumatic rupture; critical vessel reimplantation or distal clamp replacement in 13 cases of segmental spinal ischemia; and hastening the procedure or proximal clamp replacement in 3 cases of left carotid ischemia. There were no cases of unexplained multilevel SEP abnormalities. Immediate paraplegia was observed in 2 cases (1 pre-existing; 1 forecast by a 199-minute period of SEP absence due to segmental ischemia); 2 patients presented delayed paraplegias despite unchanged intraoperative SEPs, and 1 case presented a transient paraplegia due to lower motoneuronal involvement. CONCLUSIONS: SEPs efficiently identified critical vessels to be reimplanted in order to avoid immediate paraplegia. However, systematic additional vessel reimplantation, if technically feasible, and prolongation of SEP monitoring during the postoperative period with careful blood pressure control are needed to prevent delayed paraplegia.

Randomized trial of intermittent antegrade warm blood versus cold crystalloid cardioplegia.

BACKGROUND: We performed a prospective randomized trial to compare intermittent antegrade warm blood cardioplegia with intermittent antegrade and retrograde cold crystalloid cardioplegia. METHODS: Two hundred consecutive patients scheduled for isolated coronary bypass surgical procedures were randomized into two groups: Group 1 (n = 92) received cold crystalloid cardioplegia with moderate systemic hypothermia, group 2 (n = 108) received intermittent antegrade warm blood cardioplegia with systemic normothermia. Preoperative, intraoperative, and postoperative data were prospectively collected. RESULTS: For the same median number of distal anastomoses, cardiopulmonary bypass duration and total ischemic arrest duration (57.3 +/- 20.5 versus 75 +/- 22.1 minutes, p < 0.001) were shorter in group 2 than in group 1. Apart from a higher right atrial pressure in the cold cardioplegia group, no hemodynamic difference was observed. Aspartate aminotransferase, creatine kinase-MB fraction, and cardiac troponin I levels were significantly lower in group 2 than in group 1. Outcome variables were not significantly different. CONCLUSIONS: Intermittent antegrade warm blood cardioplegia results in less myocardial cell damage than cold crystalloid cardioplegia, as assessed by the release of cardiac-specific markers. This beneficial effect has only marginal clinical consequences. Normothermic bypass has no deleterious effect on end-organ function.