ABSTRACT
Recent findings have identified Klebsiella pneumoniae strains that are pan-ß-lactam susceptible (PBL-S) but piperacillin-tazobactam resistant (TZP-R) in vitro We assessed the efficacy of a humanized exposure of piperacillin-tazobactam (TZP) against 12 TZP-R/PBL-S K. pneumoniae isolates in an immunocompromised murine lung infection model. Discordance between the in vitro resistance profile and the in vivo efficacy of human-simulated TZP exposures against this phenotypic profile was observed. Additional studies are required to define the clinical implications of these TZP-R/PBL-S strains.
Subject(s)
Anti-Bacterial Agents/pharmacology , Penicillanic Acid/analogs & derivatives , Humans , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Microbial Sensitivity Tests , Penicillanic Acid/pharmacology , Piperacillin/pharmacology , Piperacillin, Tazobactam Drug Combination , beta-Lactamases/genetics , beta-Lactamases/metabolismSubject(s)
Drug Resistance, Multiple, Bacterial , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae/drug effects , Phenotype , beta-Lactams/pharmacology , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/pharmacology , Connecticut/epidemiology , Drug Therapy, Combination , Enterobacteriaceae/genetics , Enterobacteriaceae Infections/drug therapy , Escherichia coli/drug effects , Escherichia coli/genetics , Female , Humans , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Male , Microbial Sensitivity Tests , Middle Aged , Penicillanic Acid/analogs & derivatives , Penicillanic Acid/pharmacology , Piperacillin/pharmacology , Piperacillin, Tazobactam Drug Combination , Prevalence , Retrospective Studies , Risk Factors , Treatment OutcomeABSTRACT
This study investigated the level of resistance and the level of muscle activation of the prone back exercise. Fifteen male subjects with no previous history of low back injury performed two repetitions of seven exercises. These consisted of four maximal isometric voluntary contractions (MVC) and three prone back extension (PBE) exercises. The subject was lying prone on a table, the upper body was suspended off the end of the table and the legs and thighs were secured to the table with straps. Three starting positions from the horizontal were investigated, 0 degree, 30 degrees and 60 degrees, and were compared with MVC to quantify the level of effort needed to perform the task. The results showed that the three PBE exercises require a level of resistance and a level of muscle activation generally under 40% of the maximum capacity of healthy subjects. Muscle activity of the erector spinae (ES) was slightly greater when the exercise started at 60 degrees, compared to 0 degree and 30 degrees. During the static phase of the PBE exercises, the level of resistance remained at 40% relative to the peak reaction moment of the MVC, but muscular activity of ES tended to work at a lower activity level. In conclusion, since for healthy subjects PBE exercises are low resistance exercises, they seem to be more specifically designed to develop muscular endurance of the back muscles.
