Background: Clostridium difficile infection (CDI) is prevalent in healthcare settings. The emergence of hypervirulent and antibiotic resistant strains has led to an increase in CDI incidence and frequent outbreaks. While the main virulence factors are the TcdA and TcdB toxins, antibiotic resistance is thought to play a key role in the infection by and dissemination of C. difficile.Methods: A CDI outbreak involving 12 patients was detected in a tertiary care hospital, in Lisbon, which extended from January to July, with a peak in February, in 2016. The C. difficile isolates, obtained from anaerobic culture of stool samples, were subjected to antimicrobial susceptibility testing with Etest®strips against 11 antibiotics, determination of toxin genes profile, PCR-ribotyping, multilocus variable-number tandem-repeat analysis (MLVA) and whole genome sequencing (WGS).Results: Of the 12 CDI cases detected, 11 isolates from 11 patients were characterized. All isolates were tcdA-/tcdB+ and belonged to ribotype 017, and showed high level resistance to clindamycin, erythromycin, gentamicin, imipenem, moxifloxacin, rifampicin and tetracycline. The isolates belonged to four genetically related MLVA types, with six isolates forming a clonal cluster. Three outbreak isolates, each from a different MLVA type, were selected for WGS. Bioinformatics analysis showed the presence of several antibiotic resistance determinants, including the Thr82Ile substitution in gyrA, conferring moxifloxacin resistance, the substitutions His502Asn and Arg505Lys in rpoB for rifampicin resistance, the tetM gene, associated with tetracycline resistance, and two genes encoding putative aminoglycoside-modifying enzymes, aadE and aac(6′)-aph(2″). Furthermore, a not previously described 61.3 kb putative mobile element was identified, presenting a mosaic structure and containing the genes ermG, mefA/msrD and vat, associated with macrolide, lincosamide and streptogramins resistance. A substitution found in a class B penicillin-binding protein, Cys721Ser, is thought to contribute to imipenem resistance.Conclusion: We describe an epidemic, tcdA-/tcdB+, multidrug resistant clone of C. difficile from ribotype 017 associated with a hospital outbreak, providing further evidence that the lack of TcdA does not impair the infectious potential of these strains. We identified several determinants of antimicrobial resistance, including new ones located in mobile elements, highlighting the importance of horizontal gene transfer in the pathogenicity and epidemiological success of C. difficile.
Objective: To evaluate the diastolic left ventricular function by echocardiography one and three weeks after acute myocardial infarction (AMI). Method: Nineteen Wistar rats (mean weight 209 g) were utilized. After anesthesia with ketamine (50 mg/kg) and xylazine (10 mg/kg), the left coronary artery was ligated after left thoracotomy to cause myocardial infarction. The animals were divided into two groups: group A (control, n=7) and group B (n=9). Echocardiographic evaluation was undertaken in the control group and one week (B1, n=9) and three weeks (B3, n=8) post-AMI in group B animals. The cardiac function was evaluated using a 21275 A HP Sonos 1500 Echocardiography equipped with a 7.5/5.5 MHz transducer. Diastolic function was evaluated by transmitral flow, by analysis of the A wave, E wave and atrial left volume (LAV). Histological specimens were evaluated on third week. Results: There were no differences on E wave analyses (A = 62 cm/s, B1 = 65 cm/s, B3 = 69 cm/s) or A wave analyses (A = 43 cm/s, B1 = 40 cm/s, B3 = 41 cm/s) between the groups. There was an increase in LAV; A vs. B1 and A vs. B3 (A = 0.05 mL vs. B1 = 0.15 mL, p = 0.04 and A vs. B3 = 0.14 mL, p=0.01). Histological examination confirmed AMI in all animals. Conclusions: The LAV may be useful to assess the diastolic function in rats with AMI. LAV could reflect increases in left ventricular end-diastolic pressure secondary to systolic or diastolic dysfunction. Descriptors: Myocardial infarction. Myocardial contraction. Echocardiography. Resumo Objetivo: Avaliar a função ventricular diastólica do ventrículo esquerdo (VE) pelo ecocardiograma (ECO) uma e três semanas pós-infarto agudo do miocárdio (IAM). Método: Utilizaram-se 19 ratas Wistar com peso médio de 209 gramas. Os animais foram distribuídos em: grupo A, controle (n=7) submetido a ECO e não infartado; grupo B, Análise ecocardiográfica da função diastólica do ventrículo esquerdo após infarto do miocárdio em ratos Echocardiographyc analysis of the ventricular diastolic function after myocardial infarction in rats
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