| 1. |
- Berg, C G A, et al.
(författare)
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Transport equations for moist air at elevated wet bulb temperatures
- 2004
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Ingår i: Drying Technology. - 1532-2300. ; 22:1-2, s. 201-224
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Tidskriftsartikel (refereegranskat)abstract
- In meteorological applications psychrometers are used both as a humidity transfer standard and as a measurement instrument. Unfortunately wet bulb temperature, t(wb), is not a thermodynamic property and consequently, in equation linking vapor pressure and temperature, the psychrometer constant, from now on called the psychrometer coefficient, a, must be experimentally evaluated. Both theoretical formulations and experimental results show that the psychrometer coefficient, a, depends on a number of parameters. In this work a thermodynamic model of the coupled heat and mass transfer formulation of an adiabatic drying process is derived to state the adiabatic saturation temperature, t(as). Derived equations are also used in a couple of calculated examples to show to the reader why some psychrometric relations tend to be less usable at high wet bulb temperatures. The authors have found, based on the calculations, that the past conclusions of experimental studies of adiabatic evaporation from a water surface in humid air may verify both an assumption that the apparent heat transfer coefficient, is greater than the apparent mass transfer coefficient, alpha'(tot), (i.e., alpha(tot) > alpha'(tot) and t(wb) > t(as)) as well as an assumption that the apparent heat transfer coefficient is smaller than the apparent mass transfer coefficient (i.e., alpha(tot) < alpha'(tot) and t(wb) < t(as)) although pure analogy considerations propose that the apparent heat transfer coefficient is smaller than the apparent mass transfer coefficient (i.e., alpha(tot) < alpha'(tot) and t(wb) < t(as)).
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| 2. |
- Wimmerstedt, A, et al.
(författare)
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Associated antimicrobial resistance in Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes
- 2008
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 14:4, s. 315-321
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Tidskriftsartikel (refereegranskat)abstract
- Associated resistance to four to six related and unrelated antimicrobial agents was investigated in consecutive non-duplicate isolates of Escherichia coli (n = 39 425), Pseudomonas aeruginosa (n = 1070), Staphylococcus aureus (n = 7489), Streptococcus pneumoniae (n = 1604) and Streptococcus pyogenes (n = 2531). In all species, high proportions (76.5-88.9%) of isolates were susceptible to all the drugs investigated. Irrespective of species, isolates resistant to one drug were more likely to be resistant to any of the other drugs than were susceptible isolates. Thus, trimethoprim resistance in E. coli was 38.4% among ampicillin-resistant vs. 3.9% among ampicillin-susceptible isolates, and erythromycin resistance in Strep. pneumoniae was 41% among doxycycline-resistant vs. 1% among doxycycline-susceptible isolates. In all five species investigated, there was also significant associated resistance among unrelated drugs, highlighting the fact that resistance development occurs primarily among bacteria already resistant to one or more antimicrobial agents. For the clinician, pronounced resistance associations mean that when empirical therapy fails because of resistance, there is a reduced chance of choosing an alternative successful empirical agent. For the epidemiologist, who uses routine clinical susceptibility data to describe resistance development, resistance associations mean that if the dataset contains results for isolates selected on the basis of their susceptibility to another drug, structurally related or not, a bias of false resistance is introduced.
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| 3. |
- Woksepp, Hanna, et al.
(författare)
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High target attainment for beta-lactam antibiotics in intensive care unit patients when actual minimum inhibitory concentrations are applied
- 2017
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - Heidelberg : Springer. - 0934-9723 .- 1435-4373. ; 36:3, s. 553-563
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Tidskriftsartikel (refereegranskat)abstract
- Patients in the intensive care unit (ICU) are at risk for suboptimal levels of beta-lactam antibiotics, possibly leading to poor efficacy. Our aim was to investigate whether the actual minimum inhibitory concentration (MIC) compared to the more commonly used arbitrary epidemiological cut-off values (ECOFFs) would affect target attainment in ICU patients on empirical treatment with broad-spectrum beta-lactam antibiotics and to identify risk factors for not reaching target. In a prospective, multicenter study, ICU patients ae18 years old and treated with piperacillin/tazobactam, meropenem, or cefotaxime were included. Clinical and laboratory data were recorded. Serum trough antibiotic levels from three consecutive days were analyzed by liquid chromatography-mass spectrometry (LC-MS). The target was defined as the free trough concentration above the MIC (100% fT(> MIC)). MICECOFF was used as the target and, when available, the actual MIC (MICACTUAL) was applied. The median age of the patients was 70 years old, 52% (58/111) were males, and the median estimated glomerular filtration rate (eGFR) was 48.0 mL/min/1.73 m(2). The rate of patients reaching 100% fT > MICACTUAL was higher (89%, 31/35) compared to the same patients using MICECOFF (60%, p = 0.002). In total, 55% (61/111) reached 100% fT > MICECOFF. Increased renal clearance was independently associated to not reaching 100% fT > MICECOFF. On repeated sampling, > 77% of patients had stable serum drug levels around the MICECOFF. Serum concentrations of beta-lactam antibiotics vary extensively between ICU patients. The rate of patients not reaching target was markedly lower for the actual MIC than when the arbitrary MIC based on the ECOFF was used, which is important to consider in future studies.
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| 4. |
- Örtegren, Joakim, et al.
(författare)
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Clinical Value of a Routine Urine Culture Prior to Transrectal Prostate Biopsy
- 2023
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Ingår i: European Urology Open Science. - : Elsevier BV. - 2666-1691 .- 2666-1683. ; 48, s. 54-59
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Tidskriftsartikel (refereegranskat)abstract
- Background: Infectious complications after a transrectal prostate biopsy may be severe. In Sweden, a routine culture prior to all prostate biopsies was introduced to enable targeted antimicrobial prophylaxis and reduce postbiopsy infections. Objective: To investigate whether a clinical routine with a urine culture prior to a prostate biopsy and targeted prophylactic antibiotic therapy reduces postbiopsy infections. Design, setting, and participants: In 2015, a site-specific antimicrobial stewardship programme with a urine culture prior to a prostate biopsy was initiated in Region Kronoberg. To evaluate this routine, we designed a population-based register study including all men who had an outpatient prostate biopsy in 2015–2019 and a control period including all men who had a biopsy in 2010–2014, when a urinary culture was obtained only on clinical suspicion. Outcome measurements and statistical analysis: The primary outcome was infectious complications within 10 d and the secondary outcome was a change in antibiotic prophylactic treatment. An infectious complication was defined as prescription of antibiotics for urinary tract infections or admission to hospital for urinary tract infections or sepsis after a biopsy. Results and limitations: The urine culture period included 2971 prostate biopsy procedures, of which 2684 (90%) were preceded by a urine culture. The control period included 2818 procedures, of which 135 (4.8%) were preceded by a urine culture. Infectious complications were slightly more common during the urine culture period (5.0%) than during the control period (4.3%, p = 0.17), as was inpatient care for infections (3.5% vs 2.2%, p = 0.002). The routine identified 5.4% men with asymptomatic bacteriuria. Despite targeted antibiotic treatment (1.5% received a nonfluoroquinolone treatment), the rate of infectious complications (6.3%) was similar to that in the control period. Conclusions: Prebiopsy urine culture did not lead to fewer postbiopsy infections. Other measures are needed to reduce infectious complications after a prostate biopsy. Patient summary: In this report, we evaluated a routine with urine culture prior to a transrectal prostate biopsy and found that it did not lead to fewer infectious complications.
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