Evaluation of Reduced Susceptibility to Quaternary Ammonium Compounds and Bisbiguanides in Clinical Isolates and Laboratory-Generated Mutants of Staphylococcus aureus

The MICs and minimum bactericidal concentrations (MBCs) for the biocides benzalkonium chloride and chlorhexidine were determined against 1,602 clinical isolates of Staphylococcus aureus. Both compounds showed unimodal MIC and MBC distributions (2 and 4 or 8 mg/liter, respectively) with no apparent subpopulation with reduced susceptibility. To investigate further, all isolates were screened for qac genes, and 39 of these also had the promoter region of the NorA multidrug-resistant (MDR) efflux pump sequenced. The presence of qacA, qacB, qacC, and qacG genes increased the mode MIC, but not MBC, to benzalkonium chloride, while only qacA and qacB increased the chlorhexidine mode MIC. Isolates with a wild-type norA promoter or mutations in the norA promoter had similar biocide MIC distributions; notably, not all clinical isolates with norA mutations were resistant to fluoroquinolones. In vitro efflux mutants could be readily selected with ethidium bromide and acriflavine. Multiple passages were necessary to select mutants with biocides, but these mutants showed phenotypes comparable to those of mutants selected by dyes. All mutants showed changes in the promoter region of norA, but these were distinct from this region of the clinical isolates. Still, none of the in vitro mutants displayed fitness defects in a killing assay in Galleria mellonella larvae. In conclusion, our data provide an in-depth comparative overview on efflux in S. aureus mutants and clinical isolates, showing also that plasmid-encoded efflux pumps did not affect bactericidal activity of biocides. In addition, current in vitro tests appear not to be suitable for predicting levels of resistance that are clinically relevant.     

25 hydroxyvitamin D serum levels influence adequate response to bisphosphonate treatment in postmenopausal osteoporosis

It remains unclear whether vitamin D sufficiency optimizes response to bisphosphonate (BP) treatment in postmenopausal osteoporosis. We evaluated the role and possible mechanisms of vitamin D in adequate response to standard BP treatment for postmenopausal osteoporosis.MethodsWe included 120 postmenopausal osteoporotic women (aged 68 ± 8 years) receiving BP (alendronate or risedronate) at their annual follow-up, performing complete anamnesis, including treatment adherence, use of vitamin D supplements, and previous falls and fractures during the last year. We analyzed the evolution of bone mineral density (BMD) during this period and serum PTH and 25 hydroxyvitamin D (25(OH)D) and urinary NTx levels. Patients were classified as inadequate responders to antiosteoporotic treatment based on BMD loss > 2% and/or the presence of fragility fractures during the last year.ResultsThirty percent of patients showed inadequate response to BP treatment, with significantly lower levels of 25(OH)D (22.4 ± 1.3 vs. 26.6 ± 0.3 ng/ml, p = 0.01), a higher frequency of 25(OH)D levels < 30 ng/ml (91% vs. 69%, p = 0.019) and higher urinary NTx values (42.2 ± 3.9 vs. 30.9 ± 2.3 nM/mM, p = 0.01). Patients with 25(OH)D > 30 ng/ml had a greater significant increase in lumbar BMD than women with values < 30 ng/ml (3.6% vs. 0.8%, p < 0.05). The probability of inadequate response was 4-fold higher in patients with 25(OH)D < 30 (OR, 4.42; 95% CI, 1.22–15.97, p = 0.02).ConclusionsInadequate response to BP treatment is frequent in postmenopausal women with osteoporosis as is vitamin D insufficiency, despite vitamin D supplementation. Maintenance of 25(OH)D levels > 30 ng/ml is especially indicated for adequate response to BP treatment.     

Disease Progression in the Contralateral Carotid Artery after Endarterectomy

Our objectives were to establish the incidence and progression of stenotic lesions in the contralateral carotid artery (CCA) after endarterectomy, to identify subpopulations of patients at risk of contralateral disease progression, and to evaluate the efficacy of duplex scanning surveillance at detecting these lesions. We performed a prospective study on 180 patients in whom the CCA to the operated artery was healthy or showed <70% stenosis. All patients had completed a clinical and hemodynamic follow-up program, including duplex scanning of both carotids, with sessions 3 and 6 months after surgery and then every semester until 2 years. Thereafter, examinations were scheduled according to the severity of stenosis. Mean follow-up time was 26.2 months (range 1.6-67.6). Disease progression was observed in 26 lesions (15%), nine of which (5.5%) progressed to severe stenosis (SS). Kaplan-Meier event-free rates of any disease progression were 89%, 88%, 82%, and 79% for 1, 2, 3, and 4 years, respectively. Event-free rates of progression to SS were 98%, 96%, 93%, and 90.6%, respectively, for 1, 2, 3, and 4 years. The risk of progression to SS was five times higher for stenoses that were moderate at the start of the study (p = 0.025). Severe contralateral stenoses were more common and appeared later during follow-up than ipsilateral restenoses. Progression of contralateral stenotic lesions is not uncommon and is essentially related to the presence of a moderate lesion at the start of follow-up. Indeed, moderate stenosis is a risk factor for progression to SS, which appears later and more frequently than ipsilateral restenosis. It therefore seems that patients with a moderate contralateral lesion would benefit from long-term duplex ultrasound surveillance.     

Platelet function profiles in patients with type 2 diabetes and coronary artery disease on combined aspirin and clopidogrel treatment

To assess platelet function profiles in diabetic and nondiabetic patients on aspirin and clopidogrel therapy, two patient populations were included to investigate the 1) acute effects of a 300-mg clopidogrel loading dose (group 1, n = 52) and 2) long-term effects of clopidogrel (group 2, n = 120) on platelet function in diabetic compared with nondiabetic patients already on aspirin treatment. Patients were stratified according to the presence of type 2 diabetes. Platelet aggregation was assessed using light transmittance aggregometry (groups 1 and 2). Platelet activation (P-selectin expression and PAC-1 binding) was determined using whole-blood flow cytometry (group 2). Clopidogrel response was also assessed. In group 1, platelet aggregation was significantly increased in diabetic (n = 16) compared with nondiabetic (n = 36) patients at baseline and up to 24 h following a 300-mg loading dose (P = 0.005). In group 2, platelet aggregation and activation were increased in diabetic (n = 60) compared with nondiabetic (n = 60) subjects (P < 0.05 for all platelet function assays). Diabetic subjects had a higher number of clopidogrel nonresponders (P = 0.04). Diabetic patients have increased platelet reactivity compared with nondiabetic subjects on combined aspirin and clopidogrel treatment. Reduced sensitivity to antiplatelet drugs may contribute to the increased atherothombotic risk in diabetic patients.     

How far will simulators be involved into training?

The expansion of laparoscopy and endoscopic surgery has promoted a change in surgical skills acquisition. This review aims to identify problems that modulate surgical skills acquisition and the role of simulation in the current training programs. Social, medical, and working time constraints, together with patient safety issues, lead to a decreased availability of operating room (OR) training opportunities. Systematic reviews show that there is a positive “model to model” transfer of skills more evident for virtual reality (VR) simulation, although transfer from video tower exists for naïve trainees, both of which supplement standard laparoscopic training. VR to OR positive transfer is proven for laparoscopic cholecystectomy and colonoscopy/sigmoidoscopy, although not for all parameters analyzed. A mixed model integrating both types of trainers into surgical curricula may strengthen their respective possibilities. To what extent simulation will be included in the surgical training programs depends on development of objective and finer assessment tools and proficiency-based criteria.     

Surgical evaluation of candidates for donation. Selection of the kidney

Living donation for kidney transplantation is being promoted due to the shortage of organs, the improved outcomes of living donor transplants and the evolution of immunosuppression regimens. The process of organ donation from a living donor affects not only medical-surgical features but also emotional, social and economic. Using kidneys from living donors involves a great responsibility in evaluation and selection. Candidates for donation undergo an extensive set of examinations in order to optimize selection and to plan surgery. Radiological evaluation is one of the most important features of the evaluation process and selection of the kidney; it shows precisely the renal vascular anatomy, which is decisive in the choice of the kidney and helps to optimize the process and diminish risks and complications during extraction and/or tronsplantation. The advantages on imaging tests allow to evaluate potential donors in a safely, fast and almost noninvasive matter. The aim of the process is to select the kidney with less likelihood of failure due to technical reasons, and always leave the best kidney for the donor.     

Quantification of prostate shrinkage after microwave thermotherapy: a comparison of calculated cell-kill versus 3D transrectal ultrasound planimetry

PURPOSE: To compare prostate shrinkage after transurethral microwave thermotherapy (TUMT) with calculated cell-kill. MATERIALS AND METHODS: The calculated cell-kill from 33 males with benign prostatic hyperplasia (BPH) treated with TUMT according to the ProstaLund Feedback Treatment (PLFT) method was compared to the post-treatment prostate volume change. The prostate volume was estimated with three-dimensional transrectal ultrasound (3D-TRUS) planimetry at baseline, 3, 6, and 12 months follow-up. A paired t-test was used to test the statistical significance of differences between the cell-kill volume and the prostate volume change. Linear regression was used to infer a relationship between the cell-kill and the 3D-TRUS data. The reproducibility of the 3D-TRUS method was assessed in repeated measurements. RESULTS: The mean prostate volume at baseline (N=33) was 56.1cm(3). After 3 (N=25), 6 (N=29) and 12 months (N=23), it was 45.5 cm(3), 39.7 cm(3), and 45.1cm(3), respectively. The corresponding average cell-kill volume was 16.4 cm(3), 17.1cm(3), and 17.2 cm(3), respectively. Predicted cell-kill volume was significantly larger than prostate shrinkage at 3 (p<0.0001), 6 (p=0.0002), and 12 months (p<0.0001), and showed a strong correlation at 3 and 6 months (r=0.74, p<0.0001). Correlation at 12 months was moderate (r=0.57, p=0.0041). Examination and investigation variability both averaged 2.5%. CONCLUSIONS: Cell-kill calculations of the PLFT method are proportional to the 3D-TRUS prostate shrinkage by a factor of 0.5 and have a precision of approximately +/-10 cm(3) for 90% of the patients during the first year after treatment.     

Diagnostic value of differential quantification of spermatids in obstructive azoospermia

Testicular biopsies from 80 azoospermic young men were revised and the average numbers per cross-sectioned tubule of each germ cell type were calculated and compared with those of control normal testes. In 53 patients, azoospermia had an obstructive cause, and in 22 of those 53 patients more adult spermatids were found by testicular biopsy than young spermatids (over 100% in some testes), in one or both testes. However, in normal testes fewer mature spermatids than young spermatids (23.3%) were found. In the 22 patients, the causes of azoospermia were: vasectomy (7 patients), bilateral agenesis of the vas deferens (3 patients), Young syndrome (3 patients), bilateral cysts in the caput epididymidis (1 patient), bilateral inguinal herniorrhaphy (1 patient), left varicocele (1 patient), and unknown causes (6 patients). Biopsies were bilateral except for 3 cases (a vasectomized patient, a patient with Young syndrome, and a patient with obstruction due to an unknown cause). Hormonal levels were normal in the 22 patients. In addition, testicular biopsies of 3 twisted testes from 3 young adult men showing a number of adult spermatids higher than that of young spermatids were also included in the study. All testicular biopsies-including those of the twisted testes-showed an obstructive histologic pattern, consisting of a mosaic distribution of testicular lesions: mainly tubular ectasis and germ cell sloughing into the adluminal compartment of seminiferous tubules. The increase in the number of adult spermatids was bilateral in 1 of the 6 vasectomized men who underwent bilateral biopsy, and in 7 of the 11 bilaterally biopsied patients with obstructive azoospermia due to other causes. The most probable explanation for the increased number of adult spermatids is stagnation of testicular fluid, caused by sperm excretory duct obstruction. The unilateral increase in the number of adult spermatids in vasectomized men might be related to the occurrence of a spermatic granuloma (a frequent finding in vasectomy) in the proximal end of the sectioned ductus deferens ipsilateral to the testis with nonincreased adult spermatid numbers, and the absence of spermatic granuloma in the ductus deferens ipsilateral to the testis with increased adult spermatid numbers. This granuloma would produce, in addition to spermatozoon destruction, reabsorption of the testicular and epididymal fluids. The higher rate of bilateral increase, in the number of young spermatids observed in the patients with congenital lesions of the ductus deferens or the ductus epididymidis, might be related to the absence of spermatic granulomas in congenital obstructions.