Antimicrobial consumption and resistance in five Gram-negative bacterial species in a hospital from 2003 to 2011.

BACKGROUND: The misuse of antimicrobial agents increases drug resistance in bacteria. METHODS: The correlation between antimicrobial agent consumption and related resistance in the Gram-negative bacteria Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis was analyzed during the period 2003-2011. RESULTS: Among these five bacteria, overall E. coli and K. pneumoniae were more commonly isolated from bloodstream than the other species. Regarding Enterobacteriaceae, E. coli and K. pneumoniae showed annual increases of resistance to the tested antimicrobial agents; conversely, P. mirabilis exhibited reduced resistance to cefuroxime, ceftriaxone and cefepime. In contrast to the relatively low antimicrobial resistance in P. aeruginosa, A. baumannii revealed high resistance, which was over 85% resistant rate to the tested antimicrobial agents and over 80% carbapenem resistance in 2011. E. coli, K. pneumoniae, and P. mirabilis differed in development of antimicrobial resistance after consumption of the antimicrobial agents. K. pneumoniae developed resistance to all antimicrobial groups, whereas resistance in P. mirabilis was not related to any antimicrobial consumption. P. aeruginosa developed resistance to ß-lactam antimicrobials and aminoglycosides, whereas A. baumanii developed resistance to carbapenems after their use. CONCLUSION: The development of antimicrobial resistance was related to antimicrobial agents and bacterial species.

Reduced Ca2+ transport across sarcolemma but enhanced spontaneous activity in cardiomyocytes isolated from left atrium-pulmonary veins tissue of myopathic hamster.

BACKGROUND: Several lines of evidence point to a particularly important role of the left atrium (LA) in initiating and maintaining atrial fibrillation (AF). This role may be related to the location of pulmonary veins (PVs) in the LA. The aim of the present study was to investigate the action potential (AP) and ionic currents in LA-PV cardiomyocytes isolated from Bio14.6 myopathic Syrian hamsters (36-57 week-old) versus age-matched F1B healthy control hamsters. METHODS AND RESULTS: Whole-cell patch-clamp techniques were used to record AP in current-clamp mode and ionic currents in voltage-clamp mode. The results obtained show that in both healthy and myopathic LA-PV tissue spontaneously discharging cardiomyocytes can be found, but they are more numerous in myopathic (9/29) than in healthy hamsters (4/42, p < 0.05 by chi2 analysis). Myopathic myocytes have shorter AP duration (APD) with smaller ICa,L and INCX than the healthy control. The currents ITO, IK, IK1 and ICa,T are not significantly different in myopathic versus healthy cells. CONCLUSIONS: Our results indicate that in myopathic Syrian hamsters LA-PV cardiomyocytes are more prone to automatic rhythms. Also, they show altered electrophysiologic properties, which may be due to abnormal Ca2+ channels and may account for contractile dysfunction.