Interplay of nasal and rectal carriage of Staphylococcus aureus in intensive care unit patients.

The aim of this study was to investigate the relationship between nasal and rectal Staphylococcus aureus carriage in intensive care unit (ICU) patients and the occurrence of ICU-acquired infections related to S. aureus carriage. Three hundred and ninety-five patients admitted in ICU were screened for S. aureus nasal and rectal carriages and followed to record S. aureus infections during their stay. S. aureus strains were genotyped by arbitrarily primed PCR, spa-typing, microarray and whole genome sequencing. At ICU admission, 112 of 363 (30.9%) patients carried S. aureus including 61 (16.8%) exclusive nasal carriers, 40 (11.0%) combined nasal and rectal carriers and 11 (3.0%) exclusive rectal carriers. The 152 S. aureus isolates from nasal and rectal swabs belonged to 19 clonal complexes (CCs). Patients colonized in both nose and rectum harboured different strains in at least 40% of cases according to arbitrarily primed PCR data. Nasal carriers of CC5 S. aureus had an increased risk of rectal carriage (RR = 1.85, P < .05). S. aureus nasal and rectal carriage was a risk factor of S. aureus ICU-acquired infection (RR = 4.04; 95%CI [1.38-11.76]). Incidence rates of endogenous ICU-acquired infections in exclusive nasal carriers, exclusive rectal carriers and in both nasal and rectal carriers were 0.08 (5/61), 0.09 (1/11) and 0.03 (1/40), respectively (p = 0.47). Rectal swabbing increased the detection of S. aureus carriage and revealed an important diversity of S. aureus strains in ICU patients. Further studies are needed to understand how S. aureus rectal carriage increases the risk of endogenous ICU-acquired infections.

Acetaminophen-Induced Changes in Systemic Blood Pressure in Critically Ill Patients: Results of a Multicenter Cohort Study.

OBJECTIVES: We sought to assess the incidence of acetaminophen-induced hypotension. Our secondary objectives were to describe systemic hemodynamic changes and factors associated with this complication. DESIGN: Prospective observational study. SETTING: Three ICUs. PATIENTS: Adult patients requiring IV acetaminophen infusion. Arterial pressure was monitored via an arterial catheter for 3 hours. Hypotension was defined as a decrease in the mean arterial pressure of greater than or equal to 15% compared with the baseline. RESULTS: Overall, 160 patients were included in this study. Eighty-three patients (51.9%) experienced acetaminophen-induced hypotension according to our definition. In patients with acetaminophen-induced hypotension, the nadir mean arterial pressure was 64 mm Hg (95% CI, 54-74). Hypotension was observed 30 minutes (95% CI, 15-71) after acetaminophen infusion. Changes in mean arterial pressure were closely correlated with decreases in the diastolic arterial pressure (r = 0.92) and to a lesser extent with changes in the pulse pressure (r = 0.18) and heart rate (r = 0.09). Changes in the body temperature were not correlated with changes in mean arterial pressure (r = 0.0002; p = 0.85). None of the patients' baseline characteristics (shock, use of angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers, lactates, renal replacement therapy, chronic heart disease, and indication for acetaminophen infusion) or clinically relevant characteristics (baseline severity according to Logistic Organ Dysfunction score, need for vasopressors, use of antihypertensive agents, need for mechanical ventilation, or changes in the body temperature) were independently associated with acetaminophen-induced hypotension. Among patients with acetaminophen-induced hypotension, 29 (34.9%) required therapeutic intervention. CONCLUSIONS: Half of the patients who received IV injections of acetaminophen developed hypotension, and up to one third of the observed episodes necessitated therapeutic intervention. Adequately powered randomized studies are needed to confirm our findings, provide an accurate estimation of the consequences of acetaminophen-induced hypotension, and assess the pathophysiologic mechanisms involved.

Transient and Persistent Acute Kidney Injury and the Risk of Hospital Mortality in Critically Ill Patients: Results of a Multicenter Cohort Study.

OBJECTIVE: To assess the prognostic impact of transient and persistent acute kidney injury in critically ill patients. DESIGN: Retrospective analysis of prospectively collected patient data SETTING: : Six hospital ICUs. PATIENTS: Critically-ill patients with ICU stay longer than three days. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Assessment of hospital survival with respect to acute kidney injury duration. A total of 447 patients were included in this study, including 283 patients (63.3%) with an acute kidney injury at admission (175 and 108 patients with persistent and transient acute kidney injury, respectively). Patients with persistent acute kidney injury more frequently had stage 3 acute kidney injury (42.9% vs 30.6%; p = 0.04). Hospital survival was 76.2% (n = 125) in patients without acute kidney injury, 70.4% (n = 76) in patients with transient acute kidney injury, and 61.1% (n = 107) in patients with persistent acute kidney injury. After adjustment for confounding factors, the factors associated with lower hospital survival were the need for vasopressors (odds ratio, 0.65; 95% CI, 0.43-0.98) and the presence of persistent acute kidney injury (odds ratio, 0.58; 95% CI, 0.36-0.95). When included in the final model, stage 3 acute kidney injury was independently associated with a lower hospital survival (odds ratio, 0.83; 95% CI, 0.70-0.98), and persistent acute kidney injury was no longer associated with outcome. CONCLUSION: Two thirds of the critically ill patients with acute kidney injury have persistent acute kidney injury. Although mortality increased progressively with the duration of acute kidney injury, we found no independent association between this duration and patient outcome when the acute kidney injury severity is taken into account. Our results suggest that the classical "prerenal acute kidney injury" and "acute tubular necrosis" paradigm might be of limited interest from a pathophysiological or prognostic point of view.

Acquiring procedural skills in ICUs: a prospective multicenter study*.

OBJECTIVES: Providing appropriate training of procedural skills to residents while ensuring patient safety through trainee supervision is a difficult and constant challenge. We sought to determine how effective and safe procedural skill acquisition is in French ICUs and to identify failure and complication risk factors. DESIGN: Multicenter prospective observational study. Invasive procedures performed by residents were recorded during two consecutive semesters. SETTING: Eighty-four residents. SUBJECTS: Eighty-four residents. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Number of invasive procedures performed, failure and complication rates, supervision, and assistance provided. Five thousand six hundred seventeen procedures were prospectively studied: 1,007 tracheal intubations, 1,272 arterial and 2,586 central venous catheter insertions, 457 fiberoptic bronchoscopies, and 295 chest tube insertions. During the semesters, residents performed a median of 10 intubations, 14 arterial catheter insertions, and 26 central venous catheter insertions. Complication rates were low, similar to those in the literature: 8.6% desaturation and 7.4% esophageal placement during intubation; 0.4% and 2.3% pneumothorax with jugular and subclavian central venous catheter insertions, respectively. We identified risk factors for failure and complications. Higher rates of failure and complications for intubation were associated with residents with no or little previous experience (p < 0.001); failure of internal jugular vein catheterization was associated with left-side insertion (p = 0.005) and absence of mechanical ventilation (p = 0.007). Supervision and assistance were more frequent at the beginning of the semester and for intubation and chest tube insertion. Finally, residents had less access to fiberoptic bronchoscopy and chest tube insertion. CONCLUSION: Procedural skills acquisition by residents in the ICU appears feasible and safe with complication rates comparable to what has previously been reported. We identified specific procedures and situations associated with higher failure and complication rates that could require proactive training. Questions still remain regarding minimal numbers of procedures to attain competence and how best to provide procedural training.

Renal perfusion assessment by renal Doppler during fluid challenge in sepsis.

OBJECTIVES: To assess renal resistive index variations in response to fluid challenge. DESIGN: Prospective cohort study. SETTING: Three ICUs in French teaching hospitals. PATIENTS: Consecutive patients receiving mechanical ventilation and requiring a fluid challenge. INTERVENTION: Resistive index measurement before and after fluid challenge. MEASUREMENTS AND MAIN RESULTS: Renal Doppler was used to measure resistive index and esophageal Doppler to monitor aortic blood flow. Of the 35 included patients, 17 (49%) met our definition for fluid challenge responsiveness, that is, had at least a 10% increase in aortic blood flow. After fluid challenge, mean arterial pressure increased from 73 mm Hg (interquartile range 68-79) to 80 mm Hg (75-86; p < 0.0001) and stroke volume from 50 mL (30-77) to 55 mL (39-84; p < 0.0001). Stroke volume changes after fluid challenge were +28.6% (+18.8% to +38.8%) in fluid challenge responders and +3.1% (-1.6% to 7.4%) in fluid challenge nonresponders. Renal resistive index was unchanged after fluid challenge in both nonresponders (0.72 [0.67-0.75] before and 0.71 [0.67-0.75] after fluid challenge; p = 0.62) and responders (0.70 [0.65-0.75] before and 0.72 [0.68-0.74] after fluid challenge; p = 0.11). Stroke volume showed no correlations with resistive index changes after fluid challenge in the overall population (r² = 0.04, p = 0.25), in fluid challenge responders (r² = -0.02, p = 0.61), or in fluid challenge nonresponders (r² = 0.08, p = 0.27). Stroke volume did not correlate with resistive index changes after fluid challenge in the subgroups without acute kidney injury (AKIN definition), with transient acute kidney injury, or with persistent acute kidney injury. CONCLUSION: Systemic hemodynamic changes induced by fluid challenge do not translate into resistive index variations in patients without acute kidney injury, with transient acute kidney injury, or with persistent acute kidney injury.

Diagnostic accuracy of early urinary index changes in differentiating transient from persistent acute kidney injury in critically ill patients: multicenter cohort study.

INTRODUCTION: Urinary indices have limited effectiveness in separating transient acute kidney injury (AKI) from persistent AKI in ICU patients. Their time-course may vary with the mechanism of AKI. The primary objective of this study was to evaluate the diagnostic value of changes over time of the usual urinary indices in separating transient AKI from persistent AKI. METHODS: An observational prospective multicenter study was performed in six ICUs involving 244 consecutive patients, including 97 without AKI, 54 with transient AKI, and 93 with persistent AKI. Urinary sodium, urea and creatinine were measured at ICU admission (H0) and on 6-hour urine samples during the first 24 ICU hours (H6, H12, H18, and H24). Transient AKI was defined as AKI with a cause for renal hypoperfusion and reversal within 3 days. RESULTS: Significant increases from H0 to H24 were noted in fractional excretion of urea (median, 31% (22 to 41%) and 39% (29 to 48%) at H24, P<0.0001), urinary urea/plasma urea ratio (15 (7 to 28) and 20 (9 to 40), P<0.0001), and urinary creatinine/plasma creatinine ratio (50 (24 to 101) and 57 (29 to 104), P=0.01). Fractional excretion of sodium did not change significantly during the first 24 hours in the ICU (P=0.13). Neither urinary index values at ICU admission nor changes in urinary indices between H0 and H24 performed sufficiently well to recommend their use in clinical setting (area under the receiver-operating characteristic curve≤0.65). CONCLUSION: Although urinary indices at H24 performed slightly better than those at H0 in differentiating transient AKI from persistent AKI, they remain insufficiently reliable to be clinically relevant.

Prognostic consequences of borderline dysnatremia: pay attention to minimal serum sodium change.

INTRODUCTION: To assess the prevalence of dysnatremia, including borderline changes in serum sodium concentration, and to estimate the impact of these dysnatremia on mortality after adjustment for confounders. METHODS: Observational study on a prospective database fed by 13 intensive care units (ICUs). Unselected patients with ICU stay longer than 48 h were enrolled over a 14-year period were included in this study. Mild to severe hyponatremia were defined as serum sodium concentration < 135, < 130, and < 125 mmol/L respectively. Mild to severe hypernatremia were defined as serum sodium concentration > 145, > 150, and > 155 mmol/L respectively. Borderline hyponatremia and hypernatremia were defined as serum sodium concentration between 135 and 137 mmol/L or 143 and 145 respectively. RESULTS: A total of 11,125 patients were included in this study. Among these patients, 3,047 (27.4%) had mild to severe hyponatremia at ICU admission, 2,258 (20.3%) had borderline hyponatremia at ICU admission, 1,078 (9.7%) had borderline hypernatremia and 877 (7.9%) had mild to severe hypernatremia. After adjustment for confounder, both moderate and severe hyponatremia (subdistribution hazard ratio (sHR) 1.82, 95% CI 1.002 to 1.395 and 1.27, 95% CI 1.01 to 1.60 respectively) were associated with day-30 mortality. Similarly, mild, moderate and severe hypernatremia (sHR 1.34, 95% CI 1.14 to 1.57; 1.51, 95% CI 1.15 to 1.99; and 2.64, 95% CI 2.00 to 3.81 respectively) were independently associated with day-30 mortality. CONCLUSIONS: One-third of critically ill patients had a mild to moderate dysnatremia at ICU admission. Dysnatremia, including mild changes in serum sodium concentration, is an independent risk factor for hospital mortality and should not be neglected.

Human platelets can discriminate between various bacterial LPS isoforms via TLR4 signaling and differential cytokine secretion.

Platelets are currently acknowledged as cells of innate immunity and inflammation and play a complex role in sepsis. We examined whether different types of LPS have different effects on the release of soluble signaling/effective molecules from platelets. We used platelet-rich plasma from healthy volunteers and LPS from two strains of gram-negative bacteria with disparate LPS structures. We combined LPS-stimulated platelet supernatants with reporter cells and measured the PBMC cytokine secretion profiles. Upon stimulation of platelets with both Escherichia coli O111 and Salmonella minnesota LPS, the platelet LPS::TLR4 interaction activated pathways to trigger the production of a large number of molecules. The different platelet supernatants caused differential PBMC secretion of IL-6, TNFα, and IL-8. Our data demonstrate that platelets have the capacity to sense external signals differentially through a single type of pathogen recognition receptor and adjust the innate immune response appropriately for pathogens exhibiting different types of 'danger' signals.

[Severe meprobamate poisoning: description of 146 cases in a French department]. / Intoxications graves au méprobamate : description d'une série de 146 cas dans le département de la Loire.

Meprobamate poisoning are serious and sometimes fatal. Faced with a potential stop of marketing, we conducted a multicenter retrospective study to assess the severity criteria presented by patients admitted to the ICU for severe meprobamate poisoning, whether with alone form or in combination with aceprometazine. One hundred fourty-six patients have been enrolled between January 2005 and June 2011: 38 had a single meprobamate poisoning, 104 to meprobamate and aceprometazine and 4 to both forms. At admission, 88% of patients exhibited coma (Glasgow ≤ 7) and half of them a systolic blood pressure ≤ 90 mmHg. Mortality rate was 3%. Our results did not find any significant between-group difference, either in regard of clinical or biological severity criteria. These data argue for a cessation of marketing of all meprobamate-based specialities.

Meningitis in adult patients with a negative direct cerebrospinal fluid examination: value of cytochemical markers for differential diagnosis.

INTRODUCTION: The objective of this study was to determine the ability of various parameters commonly used for the diagnosis of acute meningitis to differentiate between bacterial and viral meningitis, in adult patients with a negative direct cerebrospinal fluid (CSF) examination. METHODS: This was a prospective study, started in 1997, including all patients admitted to the emergency unit with acute meningitis and a negative direct CSF examination. Serum and CSF samples were taken immediately on admission. The patients were divided into two groups according to the type of meningitis: bacterial (BM; group I) or viral (VM; group II). The CSF parameters investigated were cytology, protein, glucose, and lactate; the serum parameters evaluated were C-reactive protein and procalcitonin. CSF/serum glucose and lactate ratios were also assessed. RESULTS: Of the 254 patients with meningitis with a negative direct CSF examination, 35 had BM and 181, VM. The most highly discriminative parameters for the differential diagnosis of BM proved to be CSF lactate, with a sensitivity of 94%, a specificity of 92%, a negative predictive value of 99%, a positive predictive value of 82% at a diagnostic cut-off level of 3.8 mmol/L (area under the curve (AUC), 0.96; 95% confidence interval (CI), 0.95 to 1), and serum procalcitonin, with a sensitivity of 95%, a specificity of 100%, a negative predictive value of 100%, and a positive predictive value of 97% at a diagnostic cut-off level of 0.28 ng/ml (AUC, 0.99; 95% CI, 0.99 to 1). CONCLUSIONS: Serum procalcitonin and CSF lactate concentrations appear to be the most highly discriminative parameters for the differential diagnosis of BM and VM.

Diagnostic performance of fractional excretion of urea in the evaluation of critically ill patients with acute kidney injury: a multicenter cohort study.

INTRODUCTION: Several factors, including diuretic use and sepsis, interfere with the fractional excretion of sodium, which is used to distinguish transient from persistent acute kidney injury (AKI). These factors do not affect the fractional excretion of urea (FeUrea). However, there are conflicting data on the diagnostic accuracy of FeUrea. METHODS: We conducted an observational, prospective, multicenter study at three ICUs in university hospitals. Unselected patients, except those with obstructive AKI, were admitted to the participating ICUs during a six-month period. Transient AKI was defined as AKI caused by renal hypoperfusion and reversal within three days. The results are reported as medians (interquartile ranges). RESULTS: A total of 203 patients were included. According to our definitions, 67 had no AKI, 54 had transient AKI and 82 had persistent AKI. FeUrea was 39% (28 to 40) in the no-AKI group, 41% (29 to 54) in the transient AKI group and 32% (22 to 51) in the persistent AKI group (P = 0.12). FeUrea was of little help in distinguishing transient AKI from persistent AKI, with the area under the receiver operating characteristic curve being 0.59 (95% confidence interval, 0.49 to 0.70; P = 0.06). Sensitivity was 63% and specificity was 54% with a cutoff of 35%. In the subgroup of patients receiving diuretics, the results were similar. CONCLUSIONS: FeUrea may be of little help in distinguishing transient AKI from persistent AKI in critically ill patients, including those receiving diuretic therapy. Additional studies are needed to evaluate alternative markers or strategies to differentiate transient from persistent AKI.

Prospective determination of serum ceftazidime concentrations in intensive care units.

INTRODUCTION: The purpose of this study was to assess the value of a serum assay for ceftazidime (CAZ) in patients in the intensive care unit (ICU) of the Saint-Etienne University Teaching Hospital and in other ICUs in the region to optimize therapy. MATERIAL AND METHODS: Between November 1, 2005, and February 29, 2008, for patients hospitalized in ICUs not on dialysis and undergoing continuous CAZ infusion, serum assay of the antibiotic was performed 36 to 48 hours after the start of treatment using a single serum sample. The target serum CAZ concentration was 40 +/- 10 mg/L with a concentration/minimum inhibitory concentration ratio of 5 or greater x minimum inhibitory concentration of CAZ when a strain was isolated. RESULTS: Serum CAZ concentration was determined in 92 patients (28 females, 64 males) receiving CAZ by continuous infusion. The mean age was 66 years (range, 19-89 years) and the mean weight was 73 kg (range, 33-122 kg). The CAZ dose was between 1 g and 6 g/24 hours. The mean serum CAZ concentration was 46.9 mg/L (range, 7.4-162.3 mg/L). Serum CAZ concentrations were as follows: 30 to 50 mg/L in 35.9% of patients, less than 30 mg/L in 36.9%, and greater than 50 mg/L in 27.2%. Infection was documented in 51 patients, with 42 strains of Pseudomonas aeruginosa being detected. The serum concentration/minimum inhibitory concentration ratio was 5 or greater for 84.3%. Antibiotic dosage was adjusted based on the CAZ assay results. CONCLUSION: Our study suggests that CAZ measurement is needed in ICUs to achieve adequate CAZ concentrations to avoid treatment toxicity and to achieve efficacy as rapidly as possible, particularly in strains having limited susceptibility to antibiotics.

Remote ischemic conditioning in septic shock (RECO-Sepsis): study protocol for a randomized controlled trial.

BACKGROUND: Septic shock is a major public health problem that is associated with up to 50% mortality. Unfavorable outcomes are mainly attributed to multiple organ failure (MOF) resulting from an uncontrolled inflammatory response and ischemia-reperfusion processes. REmote ischemic COnditioning (RECO) is a promising intervention to prevent ischemia-reperfusion injury. We hypothesize that RECO would reduce the severity of septic shock-induced MOF. METHODS/DESIGN: RECO in septic shock patients (RECO-Sepsis study) is an ongoing, prospective, multicenter, randomized, open-label trial, testing whether RECO, as an adjuvant therapy to conventional treatment in septic shock, decreases the severity of MOF as assessed by the Sequential Organ Failure Assessment (SOFA) score. Adult patients admitted to an intensive care unit with documented or suspected infection, lactatemia > 2 mmol/l, and treated with norepinephrine for less than 12 h are potentially eligible for the study. Non-inclusion criteria are: having expressed the wish not to be resuscitated, contraindication for the use of a brachial cuff on both arms, intercurrent disease with an expected life expectancy of less than 24 h, cardiac arrest, and pregnant or breastfeeding women. After enrollment, patients are randomized (n = 180) 1:1 to receive RECO or no adjunctive intervention. RECO consists of four cycles of cuff inflation to 200 mmHg for 5 min and then deflation to 0 mmHg for another 5 min. RECO is performed at inclusion and repeated 12 and 24 h later. The primary endpoint is the mean daily SOFA score up to day 4 after inclusion. Secondary outcomes include the need for organ support, hospital length of stay, and 90-day mortality. DISCUSSION: Results of this proof-of-concept trial should provide information on the efficacy of RECO in patients with septic shock. TRIAL REGISTRATION: ClinicalTrials.gov, ID: identifier: NCT03201575 . Registered on 28 June 2017.

Frequency and prognostic impact of acute kidney injury in patients with acute pulmonary embolism. Data from the RIETE registry.

RATIONALE: Acute kidney injury (AKI) is associated with a poor outcome. Although pulmonary embolism (PE) may promote AKI through renal congestion and/or hemodynamic instability, its frequency and influence on outcome in patients with acute PE have been poorly studied. METHODS: The frequency of AKI (defined according to the "Kidney Disease: Improving Global Outcomes" definition) at baseline and its influence on the 30-day mortality was evaluated in patients with acute PE from the RIETE (Registro Informatizado Enfermedad TromboEmbolica) registry. We used multivariate analysis to assess whether the presence of AKI influenced the risk for 30-day death. RESULTS: The study included 21,131 patients, of whom 6222 (29.5%) had AKI at baseline: 4385 patients (21%) in stage 1, 1385 (6.5%) in stage 2 and 452 (2%) in stage 3. The proportion of patients with high-risk PE in those with no AKI, AKI stage 1, AKI stage 2 or AKI stage 3 was: 2.8%, 5.3%, 8.8% and 12%, respectively (p < 0.001). After 30 days, 1236 patients (5.9%) died. Overall mortality was 4% in patients with no AKI, 8.4% in AKI stage 1, 14% in AKI stage 2 and 17% in AKI stage 3 (all p < 0.001). AKI was independently associated with an increased risk of all-cause death at 30 days (odds ratio = 1.25; 95%CI: 1.02-1.54). CONCLUSIONS: One in every 3-4 patients with acute PE had AKI at baseline. The presence of AKI independently predicted 30-day mortality. This study suggests that AKI may deserve to be evaluated as a prognostic factor in patients with acute PE.

Can emergency physicians identify a high mortality subgroup of patients with sepsis: role of procalcitonin.

OBJECTIVE: To assess the potential role of procalcitonin and tumor necrosis factor-alpha, interleukin-6 and interleukin-8, in the prognosis of patients with sepsis. DESIGN: Prospective study. SETTING: The emergency unit of a teaching hospital. PATIENTS: We included 131 patients with sepsis: 15 (12%) with septic shock, 20 (15%) with severe sepsis and 96 (73%) with sepsis. MEASUREMENTS AND MAIN RESULTS: Out of the 131 patients, 112 (85.5%) survived and 19 (14.5%) died. These two groups of patients differed with regard to simplified acute physiology score II, severity of infectious disease and underlying disease, bacteremia and type of microorganisms. The mean serum levels of tumor necrosis factor, interleukin-6, interleukin-8, procalcitonin and lactates at study entry were higher in nonsurvivors than in survivors. Multivariate regression analysis showed the most significant of these variables to be serum procalcitonin level (P=0.0007), simplified acute physiology score II (P=0.03) and serum lactate level (P=0.03). Using a model incorporating these three variables, with a cut-off value corresponding to a 15% probability of predicting mortality, death could be correctly predicted in 99.5% of cases and survival in 95%. This cut-off value allowed us to maximize the prediction of death. When serum procalcitonin levels were not taken into account, the best model included simplified acute physiology score II and serum lactate and interleukin-6 levels, but the rate of correct prediction of death then dropped to 84%. CONCLUSIONS: Stepwise multivariate logistic regression analysis showed serum procalcitonin level to be a valuable marker of sepsis severity, compared with the 15 other clinical, biochemical and bacteriologic variables tested.

Conversion of prevalence survey data on nosocomial infections to incidence estimates: a simplified tool for surveillance?

We calculated the incidence of nosocomial infection in 2 intensive care units (ICUs) on the basis of prevalence data recorded from 1997 through 2002 and compared these estimates to cumulative incidences measured in the 2 ICUs during the same period to investigate the feasibility and the reliability of converting prevalence data to incidence estimates. Decreases in the calculated and measured incidences over time in the ICUs were found to be statistically significantly related.

Risk factors associated with methicillin-resistant Staphylococcus aureus infection in patients admitted to the ED.

OBJECTIVES: The objective of our study was to define the characteristics of patients admitted to the emergency department (ED) presenting with a methicillin-resistant Staphylococcus aureus (MRSA) infection. PATIENTS AND METHODS: The study included all patients admitted to the ED between January 2003 and December 2004 in whom a staphylococcal infection was documented. The risk factors associated with carriage of MRSA, the diagnosis made in the ED, and the treatment administered were established from the patients' medical files. The sites from which the bacteria were isolated, the spectrum of resistance of the staphylococci to different antibiotics, and the presence or absence of the gene coding for Panton-Valentin leukocidin for certain S aureus isolates were determined from the reports issued by the bacteriologic department. Two groups of patients were compared: those with an infection caused by MRSA and those with an infection due to methicillin-susceptible S aureus (MSSA). RESULTS: A total of 238 patients were included, 93 presenting with an infection caused by MRSA and 145 an infection due to MSSA. The patients harboring MRSA had a higher median age than those carrying MSSA (74 vs 61 years, P = .0001), experienced a greater loss of autonomy (according to the Knauss index), and had more comorbidity factors. Nine patients, younger than 40 years, presented with an infection due to MRSA in the absence of any comorbidity factor or any factor associated with carriage of these bacteria. Seven patients in the MRSA group were tested for Panton-Valentine leukocidin genes, and a positive result was obtained in 2 of them. Regardless of whether the infection was caused by MRSA or by MSSA, the bacteria were most frequently isolated from a cutaneous site, in 40% and 65% of the patients, respectively. Irrespective of the group, 28% of the patients presented with bacteremia. The spectrum of resistance of these MRSA strains suggested a hospital rather than community origin. The initial antibiotic therapy was rarely appropriate in the case of an infection due to MRSA. CONCLUSION: Infections caused by MRSA accounted for a high proportion of the staphylococcal infections diagnosed in the ED, necessitating a rational approach to the prescription of antibiotics for infections of this type.

Acetylsalicylic acid differentially limits the activation and expression of cell death markers in human platelets exposed to Staphylococcus aureus strains.

Beyond their hemostatic functions, platelets alter their inflammatory response according to the bacterial stimulus. Staphylococcus aureus is associated with exacerbated inflammation and thrombocytopenia, which is associated with poor prognosis during sepsis. Acetylsalicylic acid and statins prevent platelet aggregation and decrease the mortality rate during sepsis. Therefore, we assessed whether these two molecules could reduce in vitro platelet activation and the inflammatory response to S. aureus. Platelets were exposed to clinical strains of S. aureus in the presence or absence of acetylsalicylic acid or fluvastatin. Platelet activation, aggregation, and release of soluble sCD62P, sCD40 Ligand, RANTES and GROα were assessed. Platelet cell death was evaluated by analyzing the mitochondrial membrane potential, phosphatidylserine exposure, platelet microparticle release and caspase-3 activation. All S. aureus strains induced platelet activation but not aggregation and decreased the platelet count, the expression of cell death markers and the release of RANTES and GROα. Acetylsalicylic acid but not fluvastatin limited platelet activation and inflammatory factor release and restored the platelet count by protecting platelets from Staphylococcus-induced expression of cell death markers. This study demonstrates that acetylsalicylic acid limits S. aureus-induced effects on platelets by reducing cell death, revealing new strategies to reduce the platelet contribution to bacteremia-associated inflammation.