Burden of meticillin-resistant Staphylococcus aureus infections at a Swiss University hospital: excess length of stay and costs.

BACKGROUND: Meticillin-resistant Staphylococcus aureus (MRSA) infections increase hospital costs primarily by prolonging patient length of stay (LOS). AIM: To estimate the health-economic burden of MRSA infections at a Swiss University hospital using different analytical approaches. METHODS: Excess LOS was estimated by: (i) multistate modelling comparing MRSA-infected and MRSA-free patients with MRSA infection as time-dependent exposure; (ii) matching MRSA-infected patients with a cohort of MRSA-uninfected patients. The economic impact was assessed by: (i) comparing cost estimates between MRSA-infected and MRSA-free patients and multiplying excess LOS by bed-day cost; (ii) comparing real costs between MRSA-infected and MRSA-colonized non-infected patients. FINDINGS: The crude mean LOS was 37.3, 33.0 and 8.8 days for MRSA-infected, MRSA-colonized and MRSA-free patients, respectively. Excess LOS attributable to MRSA infection was 11.5 [95% confidence interval (CI): 7.9-15] or 15.3 days according to multistate modelling and matched analysis, respectively. The likelihood of discharge after MRSA infection was significantly reduced (adjusted hazard ratio: 0.69; 95% CI: 0.59-0.81). Average bed-day costs for MRSA-infected patients were 1.49- and 1.26-fold higher than for the general population hospitalized in acute wards and MRSA-colonized patients, respectively. MRSA infection resulted in an average additional cost of about 800 Swiss francs per day. CONCLUSIONS: This analysis emphasizes the financial impact of MRSA infections, demonstrates the importance of accounting for time-dependent bias and confirms that multistate modelling is a valid strategy for estimating excess LOS and costs after MRSA infection.

Multistate modelling to estimate the excess length of stay associated with meticillin-resistant Staphylococcus aureus colonisation and infection in surgical patients.

Currently available evidence on the excess length of stay (LOS) associated with nosocomial infections is limited by methodology, including time-dependent bias. To determine the excess LOS associated with nosocomial meticillin-resistant Staphylococcus aureus (MRSA) infection and colonisation, 797 MRSA-colonised, 167 MRSA-infected and 13,640 MRSA-negative surgical patients were included in a multistate model. The occurrence of MRSA infection or colonisation was the time-dependent exposure, and discharge or death was the study endpoint. The excess LOS was extracted by computing the Aalen-Johansen estimator of the matrix of transition probabilities. Multivariate Cox regression analysis was used to assess the independent effect of MRSA on excess LOS. MRSA infection prolonged LOS by 14.5 [95% confidence interval (CI): 7.8, 21.3] days compared to uninfected patients, and by 5.9 (95% CI: 0.1, 11.7) days compared to patients only colonised by MRSA. The hazard of discharge was reduced by nosocomial MRSA infection both with respect to MRSA-free patients and MRSA carriers [adjusted hazard ratio (HR): 0.69; 95% CI: 0.59, 0.81; and HR: 0.79; 95% CI: 0.65, 0.95, respectively]. MRSA carriage alone did not decrease the hazard of discharge after adjustment for confounding (HR: 1.00; 95% CI: 0.93, 1.07). Multistate modelling is a promising statistical method to evaluate the health-economic impact of nosocomial antibiotic-resistant infections.

Impact and pattern of gram-negative bacteraemia during 6 y at a large university hospital.

In order to characterize the impact and pattern of Gram-negative bacteraemia (GNB) at a Swiss University hospital and to assess the effect of multi-resistance on mortality, we conducted a 6-y retrospective cohort study using linear regression and multivariate Cox-proportional hazard analysis. 1766 patients had 1835 episodes of GNB; 61% were community-acquired. The incidence of GNB increased linearly (r2 = 0.90, p = 0.014) from 7.07 episodes to 8.32 episodes per 1000 admissions, but this trend was no longer significant after adjustment for the number of blood cultures drawn/y. The in-hospital mortality for patients with GNB decreased from 20% in 1989 to 16% in 1994 (r2 = 0.94, p = 0.005). The risk ratio for death remained unchanged over the study period and was 7-fold higher for patients with GNB than for patients without GNB. Factors independently associated with an increased hazard of death after GNB were: severity of illness as measured by exposure to intensive care (hazard ratio [HR], 1.5); age = 66-79 y (HR 1.8); GNB due to Klebsiella spp. (HR 1.7) or Pseudomonas aeruginosa (HR 1.6); and polymicrobial infection (HR 1.6). Multi-resistance was not associated with an increased risk of death (HR 1.0). Although the crude mortality of GNB decreased, the population-attributable risk ratio for death remained significant. These data suggest the absence of a major impact of multi-resistant GNB on patient mortality.

Automatic alerts for methicillin-resistant Staphylococcus aureus surveillance and control: role of a hospital information system.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an escalating problem in hospitals worldwide. The hospital reservoir for MRSA includes recognized and unrecognized colonized or infected patients, as well as previously colonized or infected patients readmitted to the hospital. Early and appropriate infection control measures (ICM) are key elements to reduce MRSA transmission and to control the hospital reservoir. OBJECTIVE: To describe the role of an expert system applied to the control of MRSA at a large medical center (1,600 beds) with high endemic rates. METHODS: The University Hospital of Geneva has an extended hospital information system (HIS), DIOGENE, structured with an open distributed architecture. It includes administrative, medical, nursing, and laboratory applications with their relational databases. Among available patient databases, clinical microbiology laboratory and admission-discharge-transfer (ADT) databases are used to generate computer alerts. A laboratory alert (lab alert) is printed daily in the Infection Control Program (ICP) offices, listing all patients with cultures positive for MRSA detected within the preceding 24 hours. Patients might be either newly detected patients colonized or infected with MRSA, or previously recognized MRSA patients having surveillance cultures. The ICP nurses subsequently go to the ward or call the ward personnel to implement ICM. A second alert, the "readmission alert," detects readmission to the hospital of any patient previously colonized or infected with MRSA by periodic queries (q 1 min) to the ADT database. The readmission alert is printed in the ICP offices, but also forwarded with added guidelines to the emergency room. RESULTS: During the first 12 months of application (July 1994 to June 1995), the lab alert detected an average of 4.6 isolates per day, corresponding to 314 hospital admissions (248 patients); the use of this alert saved time for the ICP nurses by improving work organization. There were 438 readmission alerts (1.2 alerts per day) over the study period; of 347 patients screened immediately upon readmission, 114 (33%) were positive for MRSA carriage. Delayed recognition of readmitted MRSA carriers decreased significantly after the implantation of this alert; the proportion of MRSA patients recognized at the time of admission to the hospital increased from 13% in 1993 to 40% in 1995 (P < .001). CONCLUSIONS: Hospital information system-based alerts can play an important role in the surveillance and early prevention of MRSA transmission, and it can help to recognize patterns of colonization and transmission.

Angioscotomata and morphological features of related vessels in automated perimetry.

AIMS: To determine principles which regulate the occurrence of angioscotomata in automated static perimetry, variations in light sensitivity were correlated with the location and diameter of neighbouring retinal vessels. METHODS: Ten normal eyes were tested with the Octopus 2000R, using a 0.431 degree light stimulus. Sensitivity was quantified in points located around the blind spot, according to a regular, 0.5 degree constant, grid pattern. From 336 to 443 locations were tested in each eye. The resulting printouts were superimposed on corresponding fundus photographs. At each tested point, the following five additional variables were evaluated: the diameters of the closest and the second closest vessel (in 0.1 degree units); the distances of the apparent location of the tested point to the closest and the second closest vessel (in 0.25 degree units); and the distance between the two closest vessels (in 0.25 degree units). Altogether, 3869 locations were tested and 23,214 values were quantified. RESULTS: The following two conditions were found to be related to a reduction in sensitivity: (1) proximity (< 0.25 degree) to a large vessel (> or = 0.5 degree in diameter); (2) proximity (< 0.25 degree) to one of two adjacent (< 0.5 degree distant), moderately large vessels (0.3 degree to 0.4 degree in diameter). In condition 1, sensitivity was 51.3% and specificity was 92.2%; in condition 2, sensitivity was 16.2% and specificity was 98.3%; and with a combination of conditions 1 and 2, sensitivity was 67.6% and specificity was 90.5%. Increase by 0.1 degree of an adjacent vessel which was 0.4 degree in diameter markedly affected light sensitivity. CONCLUSION: Modifications in vessel diameter are observed in a number of circumstances, including adaptive vascular response to changes in ambient conditions and obstructive disorders of retinal vessels. These findings indicate that changes in vessel diameter over time can result in fluctuation of sensitivity. It is concluded that, in contrast with what is commonly stated, when ocular media are unaltered and the subject's collaboration is adequate, temporal variations in measured thresholds do not necessarily reflect functional changes in nervous tissues in the visual pathways.

[Computer alert and quality of care: application to the surveillance of hospital infections]. / Alertes informatiques et qualité des soins: application à la surveillance des infections hospitalières.

The Centre Informatique of Geneva University Hospital is developing, in the environment of its hospital information system, DIOGENE, a computerized alert system for surveillance of hospital infections. This hospital information system is based on an open distributed architecture and a relational database system, and covers many medical applications. This environment allows the development of alerts useful for detecting patients at risk. The alerts offer to clinicians a mean to control their efficacy in patient care. They are a new application of telematics for surveillance in clinical epidemiology, and are a tool for quality assurance. Two examples of alerts established for hospital infection control activities are presented. The first alert systematically detects all cases of patients colonized by or infected with methicillin-resistant Staphylococcus aureus (MRSA). The second alert helps to organize prospective surveillance of bloodstream infections in order to identify some risk factors for infection and propose preventive measures.

[The dorso-mesencephalic syndrome. Electrooculographic study of 2 clinical cases]. / Le syndrome dorso-mésencéphalique. Etude électro-oculographique de 2 observations cliniques.

Electro-oculographic recordings of horizontal eye movements in two patients with dorso-mesencephalic lesions are analysed. Tracings shows essentially: (A) dysconjugate glissadic dysmetria, with adduction overshoot and abduction undershoot, and (B) instability of ocular fixation. Fixation instability consists of bursts of 2 or 3 bilateral to-and-fro eye movements, of 4 degree or less amplitude. During a burst there is no evident latency between successive ocular movements. Bursts often appear following horizontal refixation saccades, and are then repeated once or twice with regular intervals. In one patient, fixation instability phases are more often elicited by saccades to the right than to the left. The typical occurrence of fixation instability after the fast phase of optokinetic nystagmus is described. The alteration of ocular fixation described in our patients belongs to the general group of "saccadic intrusions" as defined by Daroff et al. (1977). Resemblance with "lightning eye movements" (Atkin and Bender, 1964) and "opposed adducting saccades" in the Sylvian aqueduct syndrome (Ochs et al., 1979) is discussed.

Convergence-evoked eyelid nystagmus.

We studied two patients with eyelid nystagmus induced by ocular convergence. The first patient, a 29-year-old man, had the signs of a cerebellar syndrome after sustaining severe craniocerebral injuries. The second patient, a 12-year-old girl, had a tumor of the anterior vermis cerebelli. After treatment with corticosteroids (Patient 1) and surgery (Patient 2), the eyelid nystagmus gradually disappeared. An alteration in the cerebellar system is the most likely cause of convergence-evoked nystagmus.

Metastatic infiltration of nerves in the cavernous sinus.

Painful dysesthesia in association with ocular motor palsies characterized intraneural carcinomatous invasion in a 48-year-old man. Transcranial biopsy of the cavernous sinus stopped the pain; the specimen confirmed the diagnosis and provided the rationale for radiation therapy. One year after treatment, the patient was healthy and pain-free, with improved ocular motor function. The source of the carcinoma remains unknown.

[Visual outcome in pituitary adenoma and supra sellar meningioma (author's transl)]. / Adénomes pituitaires et méningiomes supra-sellaires : pronostic visuel post-opératoire.

To determine factors influencing ultimate visual outcome following surgical decompression of pituitary adenoma and suprasellar meningioma, the authors analyse the post-operative visual function of 19 patients with pituitary tumors and of 11 with meningiomas encroaching upon the anterior visual pathways. Their data indicate that : visual impairment tended to be worse and of larger duration with meningiomas than with adenoma. No pre-operative data were of prognostic value for visual outcome with meningioma; for adenoma, younger age, a short duration of symptoms and transsphenoidal approach all positively influenced ultimate visual recovery. Even with minimal visual deficits, eyes tended not to recover completely.