Relevance of multidrug-resistant Pseudomonas aeruginosa infections in cystic fibrosis

Multidrug-resistant (MDR) Pseudomonas aeruginosa is an important issue for physicians who take care of patients with cystic fibrosis (CF). Here, we review the latest research on how P. aeruginosa infection causes lung function to decline and how several factors contribute to the emergence of antibiotic resistance in P. aeruginosa strains and influence the course of the infection course. However, many aspects of the practical management of patients with CF infected with MDR P. aeruginosa are still to be established. Less is known about the exact role of susceptibility testing in clinical strategies for dealing with resistant infections, and there is an urgent need to find a tool to assist in choosing the best therapeutic strategy for MDR P. aeruginosa infection. One current perception is that the selection of antibiotic therapy according to antibiogram results is an important component of the decision-making process, but other patient factors, such as previous infection history and antibiotic courses, also need to be evaluated. On the basis of the known issues and the best current data on respiratory infections caused by MDR P. aeruginosa, this review provides practical suggestions to optimize the diagnostic and therapeutic management of patients with CF who are infected with these pathogens.

Neurotoxicity induced by Cefepime in a very old hemodialysis patient

Neurotoxicity is an unusual complication of cephalosporin therapy. Only few cases of neurotoxicity induced by Cefepime have been described and probably the frequency of Cefepime-induced status epilepticus is underestimated. We report a case of an 82 year-old male, ESRD patient on chronic hemodialysis program affected by pneumonia, who received a treatment with intravenous Cefepime (1 g/day) and developed a seizure 4 days after the starting antibiotic therapy. Cefepime-induced neurotoxicity was suspected and its administration was immediately discontinued. In order to increase Cefepime clearance a hemodialysis session was urgently started and an improvement of his conscious level was observed. On the following day, after a second hemodialysis session his clinical condition and the status of neurotoxicity were completely recovered. The patient was discharged from the hospital in stable clinical condition one week later. At variance with the cases previously reported, the daily dose of Cefepime administrated to our patient was 50% lower and respected drug prescription dosage. Thus, we speculate on the hypothesis that advanced age of our patient and metabolic encephalopathy induced by chronic uremia made him more sensitive to the neurotoxicity induced by the drug. In conclusion, our case suggests that, in very old patients on long-term hemodialysis, it should be considered, to avoid neurotoxicity, to monitor the clinical neurological status, to use Cefepime at lower dosage than that allowed in patients with severe renal impairment (1 g/day) and, when possible, to evaluate Cefepime plasma levels. However, in these patients, other agents of the same class should be considered such as Cefotaxime and Ceftriaxone which are characterized by both an hepatic and renal excretion. In alternative to cephalosporins, antibiotics with the same action spectrum in the absence of neurological toxicity (i.e. Meropenem) should be recommended.

High level of physical activity preserves the cardioprotective effect of preinfarction angina in elderly patients

OBJECTIVES

The study investigated the effects of physical activity on preinfarction angina, a clinical equivalent of ischemic preconditioning (PC), in adult and elderly patients with acute myocardial infarction (AMI).

BACKGROUND

Preinfarction angina seems to confer protection against in-hospital mortality in adult but not in elderly patients. However, it has been experimentally demonstrated that exercise training restores the protective effect of PC in the aging heart.

METHODS

We retrospectively verified whether physical activity preserved the protective effect of preinfarction angina against in-hospital mortality in 557 elderly patients with AMI. Physical activity was quantified according to the Physical Activity Scale for the Elderly (PASE).

RESULTS

In-hospital mortality was 22.2% in elderly patients with preinfarction angina and 27.2% in those without (p = 0.20). When the PASE score was stratified in quartiles (0 to 40, 41 to 56, 57 to 90, >90), a high score was strongly associated with reduced in-hospital mortality (30.8%, 32.2%, 17.2% and 15.3%, respectively, p < 0.001 for trend). Interestingly, a high level of physical activity reduced in-hospital mortality in elderly patients with preinfarction angina (35.7%, 35.4%, 12.3% and 4.23%, respectively, p < 0.001 for trend) but not in those without (23.0%, 27.2%, 26.0% and 35.0%, respectively, p = 0.35 for trend). Accordingly, the protective role of preinfarction angina on in-hospital mortality was present only in elderly patients showing a high level of physical activity (adjusted odds ratio, 0.09; 95% confidence interval, 0.01 to 0.57; p < 0.05).

CONCLUSIONS

Physical activity and not preinfarction angina protects against in-hospital mortality in elderly patients with myocardial infarction. Nevertheless, the protective effect of preinfarction angina is preserved in elderly patients with a high level of physical activity.

Prognostic implications of Tc-99m sestamibi viability imaging and subsequent therapeutic strategy in patients with chronic coronary artery disease and left ventricular dysfunction

OBJECTIVES

The aim of the study was to verify the prognostic implications of viability detection using baseline-nitrate sestamibi imaging in patients with left ventricular (LV) dysfunction due to chronic coronary artery disease (CAD) submitted to different therapeutic strategies.

BACKGROUND

The prognostic meaning of preserved viability in these patients is still debated. Sestamibi is increasingly used for myocardial perfusion scintigraphy and is being accepted also as viability tracer, but no data are available about the relationship between viability in sestamibi imaging, subsequent treatment, and patient's outcome.

METHODS

Follow-up data were collected in 105 CAD patients with LV dysfunction who had undergone baseline-nitrate sestamibi perfusion imaging for viability assessment and had been later treated medically (group 1), or submitted to revascularization, which was either complete (group 2A) or incomplete (group 2B).

RESULTS

Eighteen hard events (cardiac death or nonfatal myocardial infarction) were registered during the follow-up. A significantly worse event-free survival curve was observed in the patients of group 1 (p < 0.0002) and group 2B (p < 0.03) compared to those of group 2A. Using a Cox proportional hazard model, the most powerful prognostic predictors of events were the number of nonrevascularized asynergic segments with viability in sestamibi imaging (p < 0.003, risk ratio [RR] = 1.4), and the severity of CAD (p < 0.02, RR = 1.28).

CONCLUSIONS

Viability detection in sestamibi imaging has important prognostic implications in CAD patients with LV dysfunction. Patients with preserved viability kept on medical therapy or submitted to incomplete revascularization represent high-risk groups.

Ischemic threshold and myocardial stunning in the aging heart

The aging heart appears to be more susceptible to ischemia-reperfusion injury than the adult heart. There is no evidence of an age-related difference in the threshold of myocardial ischemia and myocardial stunning. We studied the effects on mechanical, hemodynamic, and metabolic parameters of graded reduction of coronary perfusion pressure from 66 to 29 mmHg in isolated and perfused hearts from adult and senescent rats. Cardiac function was also assessed during recovery following ischemic period. In both adult and senescent hearts developed pressure and +dP/dt linearly decreased and end-diastolic pressure linearly increased with decreasing perfusion pressure. However, all mechanical parameters were more severely impaired in senescent than in adult hearts at 37 mmHg and 29 mmHg perfusion pressure, respectively (p < 0.01 vs. adult). At 29 mmHg, in both adult and senescent hearts lactate production similarly increased whereas creatine kinase leakage did not differ from controls. Developed pressure recovered more slowly in senescent than in adult hearts (p < 0.001) in the absence of cellular damage and in the presence of restoration of coronary flow. Lactate production observed at the same step of coronary perfusion pressure suggests that the ischemic threshold is similar in adult and senescent hearts. The slow recovery of myocardial contractility after the ischemic period observed in senescent hearts suggests an age-related increase in myocardial stunning.