[Using a 48-hour delay from admission to the first positive culture without any other consideration: an accurate method to differentiate acquired and imported methicillin-resistant Staphylococcus aureus?]. / Retenir un délai de 48 heures entre l'admission des patients et le premier prélèvement positif est-il suffisant pour différencier les souches acquises à l'hôpital et importées de Staphylococcus aureus résistant à la méticilline?

To differentiate imported and acquired strains of methicillin-resistant Staphylococcus aureus (MRSA), a 48-hour delay from hospital admission to the first MRSA-positive culture is usually considered. To assess if taking into account this delay without any other consideration is an accurate method, we defined 3 situations for whom we considered the MRSA acquisition status as questionable. The other situations were defined as either acquired MRSA or imported MRSA. We determined the acquisition status of MRSA (acquired, imported, or questionable) isolated during a 20-month period by considering or not considering screening samples performed on admission. The ratio "imported MRSA/acquired MRSA" (I/A) was calculated according to (1) the consideration of MRSA with questionable status as imported or acquired, and (2) the consideration of screening samples or not in the calculation of the ratio. The acquisition status in our hospital was questionable in 3.6% of patients when all samples were considered and in 12,0% when only clinical samples were taken into account (p = 0,01). The ratio I/A was 4-fold higher by considering both clinical and screening cultures and questionable status as imported than by considering only clinical samples and questionable status as acquired. Using a 48-hour delay without any other consideration is probably an accurate method to differentiate acquired and imported MRSA when a selective screening programme at admission in operational. Conversely, this definition seems to be more hazardous in the absence of screening.

Impact of selective screening in the emergency department on meticillin-resistant Staphylococcus aureus control programmes.

Identification of the meticillin-resistant Staphylococcus aureus (MRSA) reservoir by active screening followed by the implementation of contact precautions is one of the major components of MRSA control programmes. The objective of this study was to evaluate the results of a programme of selective screening in an emergency department (ED) and the appropriateness of the contact precautions implemented. This was estimated by distinguishing necessary and unnecessary days of contact precautions. This estimation was performed for all days of contact precautions and, more specifically, for days of preventive contact precautions implemented before the availability of screening results. During a three-year period, screening of MRSA carriers was performed on 0.95% (N=605) of patients visiting the emergency ward. Among the 193 (31.9%) MRSA carriers identified, 159 were hospitalized in the short-length-hospitalization area (SLHA) of the ED and/or in other wards. Among the 140 patients admitted to the SLHA, 44 were hospitalized for at least 48 h, with a mean length of hospitalization of 5.9 days. The cumulative duration of hospitalization of carriers identified by screening was 1897 days. In total, 2370 days of contact precautions (including 924 days of preventive precautions) were implemented for patients screened in the ED. Considering the whole hospital, the appropriateness of this entire programme of contact precautions for patients screened in the ED was 80.0% (52.1% for the SLHA), whereas the specific appropriateness of preventive isolation days was 48.6% (43.6% for the SLHA). This study underscores the risk of MRSA cross-transmission in the SLHA, and the usefulness of implementing a control programme of screening carriers in the ED.

Sedation, sucralfate, and antibiotic use are potential means for protection against early-onset ventilator-associated pneumonia.

To examine risk factors for early-onset ventilator-associated pneumonia (EOP) in patients requiring mechanical ventilation (MV), we performed a prospective cohort study that included 747 patients. Pneumonia was defined as a positive result for a protected quantitative distal sample. EOP was defined as pneumonia that occurred from day 3 to day 7 of MV. Eighty patients (10.7%) experienced EOP. Independent predictors of EOP were male sex (odds ratio [OR], 2.06; 95% confidence interval [CI], 1.18-3.63), actual Glasgow Coma Scale value of 6-13 (OR, 1.95; 95% CI, 1.2-3.18), high Logistic Organ Dysfunction score at day 2 (OR, 1.12 per point; 95% CI, 1.02-1.23), unplanned extubation (OR, 3.19; 95% CI, 1.28-7.92), and sucralfate use (OR, 1.81; 95% CI, 1.01-3.26). Protection occurred with use of aminoglycosides (OR, 0.36; 95% CI, 0.17-0.76), beta -lactams and/or beta -lactamase inhibitors (OR, 0.47; 95% CI, 0.28-0.83), or third-generation cephalosporins (OR, 0.33; 95% CI, 0.16-0.74). Sucralfate use and unplanned extubation are independent risk factors for EOP. Use of aminoglycosides, beta-lactams/ beta-lactamase inhibitors, or third-generation cephalosporins protects against EOP.

Accuracy of a composite score using daily SAPS II and LOD scores for predicting hospital mortality in ICU patients hospitalized for more than 72 h.

UNLABELLED: In most databases used to build general severity scores the median duration of intensive care unit (ICU) stay is less than 3 days. Consequently, these scores are not the most appropriate tools for measuring prognosis in studies dealing with ICU patients hospitalized for more than 72 h. PURPOSE: To develop a new prognostic model based on a general severity score (SAPS II), an organ dysfunction score (LOD) and evolution of both scores during the first 3 days of ICU stay. DESIGN: Prospective multicenter study. SETTING: Twenty-eight intensive care units (ICUs) in France. PATIENTS: A training data-set was created with four ICUs during an 18-month period (893 patients). Seventy percent of the patients were medical (628) aged 66 years. The median SAPS II was 38. The ICU and hospital mortality rates were 22.7% and 30%, respectively. Forty-seven percent (420 patients) were transferred from hospital wards. In this population, the calibration (Hosmer-Lemeshow chi-square: 37.4, P = 0.001) and the discrimination [area under the ROC curves: 0.744 (95 % CI: 0.714-0.773)] of the original SAPS II were relatively poor. A validation data set was created with a random panel of 24 French ICUs during March 1999 (312 patients). MEASUREMENTS AND MAIN RESULTS: The LOD and SAPS II scores were calculated during the first (SAPS1, LOD1), second (SAPS2, LOD2), and third (SAPS3, LOD3) calendar days. The LOD and SAPS scores alterations were assigned the value "1" when scores increased with time and "0" otherwise. A multivariable logistic regression model was used to select variables measured during the first three calendar days, and independently associated with death. Selected variables were: SAPS II at admission [OR: 1.04 (95 % CI: 1.027-1.053) per point], LOD [OR: 1.16 (95 % CI: 1.085-1.253) per point], transfer from ward [OR: 1.74 (95 % CI: 1.25-2.42)], as well as SAPS3-SAPS2 alterations [OR: 1.516 (95 % CI: 1.04-2.22)], and LOD3-LOD2 alterations [OR: 2.00 (95 % CI: 1.29-3.11)]. The final model has good calibration and discrimination properties in the training data set [area under the ROC curve: 0.794 (95 % CI: 0.766-0.820), Hosmer-Lemeshow C statistic: 5.56, P = 0.7]. In the validation data set, the model maintained good accuracy [area under the ROC curve: 0.826 (95 % CI: 0.780-0.867), Hosmer-Lemeshow C statistic: 7.14, P = 0.5]. CONCLUSIONS: The new model using SAPS II and LOD and their evolution during the first calendar days has good discrimination and calibration properties. We propose its use for benchmarking and evaluating the over-risk of death associated with ICU-acquired nosocomial infections.

Accuracy of delayed cultures of plugged telescoping catheter samples for diagnosing bacterial pneumonia.

OBJECTIVE: It is not always feasible to culture immediately bacteriologic samples of protected pulmonary specimens on a 24-hr basis before starting antibiotic treatment. We have evaluated the effect of delaying the culture of immediate plugged telescoping catheter (PTC) samples performed before starting antibiotherapy. DESIGN: Prospective paired comparisons study. SETTING: Intensive care unit in a university hospital. PATIENTS: Ninety-nine PTCs were performed on 68 intensive care unit patients suspected of nosocomial or community- acquired bacterial pneumonia. INTERVENTION: PTC samples were divided into two aliquots: one for immediate (H0) analysis and one for storage at 4 degrees C (H24) for 24 hrs before being cultured. MEASUREMENTS AND MAIN RESULTS: The results from these delayed cultures (H24) were compared with those from immediate ones (H0). All negative H0 samples (n = 59) were also negative at H24. Forty PTCs yielded one or more microorganisms, with a total of 69 microorganisms in one or both samples. H0 and H24 cultures were concordant in 119 of 128 (97.9%) cases (kappa coefficient value 0.79) with a threshold of 103 colony-forming units (cfu)/mL. Agreement between paired cultures was very good. The bias calculated as the mean difference between paired culture results was 0.128 +/- 1.024 (Deltalog). Concordance using the 103 cfu/mL threshold (102/107 cases, kappa coefficient value 0.82) and agreement were enhanced (0.067 +/- 0.645) when possible contaminants were excluded (n = 21). CONCLUSIONS: Storing PTC specimens for 24 hrs at 4 degrees C is an acceptable alternative when culturing cannot be performed immediately. This allows starting antibiotic treatment without any delay.

Delayed treatment contributes to mortality in ICU patients with severe active pulmonary tuberculosis and acute respiratory failure.

OBJECTIVES: To clarify the patterns of pulmonary tuberculosis (TB) that should result in a high index of suspicion, to increase the chances of early therapy and to identify predictors of 30-day mortality. PATIENTS AND METHODS: Retrospective, 7-year study in two medical intensive care units (ICUs). All patients admitted with pulmonary TB were enrolled. Clinical and laboratory data at admission and events within 48 h of admission were collected. Predictors of 30-day mortality were identified by univariate and multivariate analysis. RESULTS: The study included 99 patients with a median age of 41 years. Immunodeficiency was present in 60 patients, including 38 with AIDS. Fifty-nine patients had pulmonary TB alone, 22 also had extrapulmonary TB and 18 had miliary. All 99 patients were admitted for acute respiratory failure, some also with shock (20), neurologic disorders (18) or acute renal failure (10). Mechanical ventilation was needed in 50 patients; 22 patients met criteria for acute respiratory distress syndrome (ARDS). The 30-day mortality rate was 26.2%. Four factors independently predicted mortality: a time from symptom onset to treatment of more than 1 month (OR, 3.49; CI, 1.20-10.20), the number of organ failures (OR, 3.15; CI, 1.76-5.76), a serum albumin level above 20 g/l (OR, 3.96; CI, 1.04-15.10), and a larger number of lobes involved on chest radiograph (OR, 1.83; CI, 1.12-2.98). CONCLUSION: Delayed clinical suspicion and treatment of active pulmonary TB with respiratory failure may contribute to the persistently high mortality rates in ICU patients with these diseases.

[Prevention of nosocomial pneumonia in patients treated with invasive ventilation]. / Prévention des pneumonies nosocomiales chez les patients traités par ventilation invasive.

Nosocomial pneumonia is one of the primary causes of nosocomial infection in intensive care patients, leading to high mortality and prolonged hospitalization. Mechanical ventilation and its duration are major risk factors. When invasive ventilation is indispensable, preventive measures should aim at optimizing patient care by carefully applying basic rules of hygiene and recommended procedures for use of ventilation equipment. Different preventive measures have been proposed and should be considered in light of several criteria: the cost/benefit ratio, the level of proof (size of the study population, quality and pertinence of judgement criteria), feasibility, routine cost, and absence of secondary collateral adverse effects.

Acute, fatal, oral chromic acid poisoning.

CASE REPORT: We report a 35-year-old woman who developed severe acidosis, massive gastrointestinal hemorrhage, acute renal failure, and hepatic injury following ingestion of chromic acid (50 mL) and died 12 hours after ingestion. Postmortem liver biopsy revealed a fatty degeneration with chromium concentration 3.6 mumol/g. The kidney, with chromium concentration 2.6 mumol/g, had extensive necrosis and ischemic lesions. Erythrocyte chromium was 1903 mumol/L at 3 hours declining to 865 mumol/L at 11 hours.

Successful rescue in a patient with high dose methotrexate-induced nephrotoxicity and acute renal failure.

We describe the case of a 35-year old male who developed acute renal failure following high dose methotrexate therapy for Burkitt's non Hodgkin lymphoma. Serum methotrexate levels reached 37 micromol/l, and remained higher than 1 micromol/l for more than a week. Folinic acid rescue was intensified to 200-400 mg intravenously every 4 hours. As methotrexate binds markedly to proteins, plasma exchange was initially chosen, 4 sessions being performed from day 2 to day 4. The methotrexate pharmacokinetic profile was not significantly modified during plasma exchange, and serum drug level was 3 micromol/l. Continuous veno-venous hemodiafiltration was therefore performed from day 5 to day 10. This procedure also seemed ineffective, with evidence of low ultrafiltrate clearance. No extrarenal toxicity was observed in our patient. Thus, conventional extrarenal procedures appear to have a limited role in the setting of overexposure to methotrexate. The use of very high doses of folinic acid in our case probably played a major role in the eventual favorable outcome.

Alveolar hemorrhage. Diagnostic criteria and results in 194 immunocompromised hosts.

To establish the diagnosis of alveolar hemorrhage (AH) in cells recovered by bronchoalveolar lavage (BAL), Golde and colleagues created a score based on the hemosiderin content of alveolar macrophages stained with Prussian blue. We used an easier method, calculating the percentage of siderophages among the total alveolar macrophages recovered by BAL. We have retrospectively studied this method in 240 BALs performed in 194 immunocompromised patients. Prussian blue staining was performed on each BAL sample, and the Golde score was calculated for 47 samples chosen at random. The methods were compared for diagnosing AH. The percentage of siderophages correlated well with the Golde score. AH was defined by at least 20% siderophages. This definition was validated by comparison with the method of Kahn and coworkers. AH was present in 87 (36%) of the samples and was significantly associated with four parameters: thrombocytopenia (< 50,000/mm3), other abnormal coagulation parameters, renal failure (creatinine > or = 2.5 mg/dl), and a history of heavy smoking. The diagnosis of AH did not correlate with either the cause or the outcome of pneumonia. AH was seen more frequently in cardiac transplant patients (75%). In our experience, (1) a percentage of siderophages > or = 20% is sufficient and is an easier determinant of the diagnosis of AH than the Golde score; and (2) AH is rarely the sole cause of lung injury and is usually associated with other causes of pneumonia. AH may be considered more as a sign than as a distinct disease in this population.

A search for mycobacterial DNA in granulomatous tissues from patients with sarcoidosis using the polymerase chain reaction.

We have used the polymerase chain reaction as a tool to detect the presence of mycobacterial DNA from organisms of the Mycobacterium tuberculosis complex and other species of mycobacteria in samples from patients with sarcoidosis. Using systems based on the amplification of a fragment of the gene coding for the 65-kD mycobacterial antigen, which were demonstrated to detect approximately 20 mycobacterial genomes/microgram total DNA, DNA from M. tuberculosis was reproducibly identified in DNA extracted from granulomatous tissues from two patients with sarcoidosis, but could not be detected in DNA extracted from tissue biopsies (n = 16) or cells recovered by lavage (n = 6) from most sarcoid patients or from control subjects (n = 22). Using a system based on the amplification of a fragment of the IS6110 insertion element, which could reliably detect two genomes of mycobacterial DNA/microgram total DNA, no additional positive results were observed. In an effort to identify another species of Mycobacterium present in granulomatous tissues from sarcoid patients but not control tissues, a fragment of the 65-kD mycobacterial antigen was amplified and then reamplified using "nested" primers recognizing sequences that are highly conserved among mycobacteria and closely related species, and the amplified DNA products were cloned and sequenced. Amplified DNA was observed in a minority of samples from patients and control subjects (32/84 and 34/77 attempts, respectively, p greater than 0.2), resulting from amplification of DNA from at least 17 different organisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of mycobacterial DNA in pleural fluid from patients with tuberculous pleurisy by means of the polymerase chain reaction: comparison of two protocols.

BACKGROUND: The detection of mycobacterial DNA in clinical samples on the basis of the polymerase chain reaction is a promising approach for the rapid diagnosis of tuberculous infections. No consensus exists, however, about which protocols are most sensitive, and the usefulness of this approach in the diagnosis of tuberculous effusions has been assessed in few patients. METHODS: The sensitivity of two protocols was compared for the detection of DNA from Mycobacterium tuberculosis in samples containing known amounts of mycobacterial DNA and in DNA extracted from 15 tuberculous pleural effusions. The results obtained for pleural fluid have been compared with cytological findings and with results obtained by standard microbiological techniques. RESULTS: Mycobacteria could be detected by acid fast staining in none and by culture in three of the 15 pleural fluid samples. A protocol based on the detection of the IS6110 insertion element (which could detect one mycobacterial genome/sample reproducibly) gave a positive result in nine of the 15 tuberculous effusions, though some samples were only intermittently positive (p less than 0.05 compared with culture). In contrast, a protocol based on the detection of the gene coding for the 65 kD mycobacterial antigen (which could detect mycobacterial genomes only if there were at least 10/sample) gave a positive result in three of the 15 tuberculous effusions. Pleural fluid that was always positive with the amplification procedure detecting the IS6110 sequence contained more neutrophils (30% (SD 27%)) than samples that were intermittently positive or always negative (3% (3%)); mycobacterial DNA was never detected in the four samples containing less than 1% neutrophils. CONCLUSIONS: The amplification of the IS6110 insertion element represents a rapid and sensitive means of detecting M tuberculosis in tuberculous effusions. The enrichment of cells containing mycobacteria (possibly neutrophils) before DNA extraction may be required to improve the sensitivity of this approach.