MRI-based brain volumetry in chronic whiplash patients: no evidence for traumatic brain injury.

INTRODUCTION: Cognitive complaints, such as poor concentration and memory deficits, are frequent after whiplash injury and play an important role in disability. The origin of these complaints is discussed controversially. Some authors postulate brain lesions as a consequence of whiplash injuries. Potential diffuse axonal injury (DAI) with subsequent atrophy of the brain and ventricular expansion is of particular interest as focal brain lesions have not been documented so far in whiplash injury. OBJECTIVE: To investigate whether traumatic brain injury can be identified using a magnetic resonance (MR)-based quantitative analysis of normalized ventricle-brain ratios (VBR) in chronic whiplash patients with subjective cognitive impairment that cannot be objectively confirmed by neuropsychological testing. MATERIALS AND METHODS: MR examination was performed in 21 patients with whiplash injury and symptom persistence for 9 months on average and in 18 matched healthy controls. Conventional MR imaging (MRI) was used to assess the volumes of grey and white matter and of ventricles. The normalized VBR was calculated. RESULTS: The values of normalized VBR did not differ in whiplash patients when compared with that in healthy controls (F = 0.216, P = 0.645). CONCLUSIONS: This study does not support loss of brain tissue following whiplash injury as measured by VBR. On this basis, traumatic brain injury with subsequent DAI does not seem to be the underlying mechanism for persistent concentration and memory deficits that are subjectively reported but not objectively verifiable as neuropsychological deficits.

Implementation of isolation precautions: role of a targeted information flyer.

Isolation precautions are advocated in most countries for patients harbouring multi-drug-resistant organisms. We evaluated the impact of a targeted information flyer on the implementation of isolation precautions for patients with methicillin-resistant Staphylococcus aureus (MRSA). A flyer providing a quick reference to the steps to be implemented following detection of MRSA was sent systematically by the microbiologists with all results displaying MRSA. Infection control staff compared isolation precautions in two three-month periods: the first (control) period before implementation of the flyer and the second (intervention) period after implementation of the flyer. Compared with the control period, compliance with isolation precautions increased significantly in the intervention period. In intensive care units, there was a sign posted on the door for 31 of 38 (82%) patients in the control period, and 33 out of 34 (97%) in the intervention period (P=0.06). Use of gowns increased from 82% to 100% (P=0.01), use of dedicated materials increased from 84% to 100% (P=0.03), availability of alcohol hand rub increased from 82% to 94% (P=0.10), and the proportion of MRSA patients in private rooms increased from 71% to 91% of the cases (P=0.07). In conclusion, compliance with isolation precautions increased after attaching a flyer to all MRSA-positive bacteriological results.

High rate of faecal carriage of extended-spectrum ß-lactamase-producing Enterobacteriaceae in healthy children in Bangui, Central African Republic.

The aim of this study was to estimate the prevalence of extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) in faeces of healthy children aged 0-59 months in Bangui (Central African Republic). Stool samples of 134 children, recruited for a matched case-control study, were cultured on a commercial ESBL-selective chromogenic medium (CHROMagar ESBL, France). The phenotypic resistance patterns of isolated strains were investigated, as well as the genetic basis for antibiotic resistance. The factors associated with increased risk for ESBL-E carriage were also studied. The prevalence of ESBL-E carriage was 59% (79/134), one of the highest reported worldwide. The only factor found to be associated with carriage was living in a highest-income family (p=0.03). In all, 83 ESBL-E were recovered as simultaneous carriage of two strains was detected in four children. blaCTX-M-15 was found in all strains except two, frequently associated with qnr (54/81, 66%) and aac(6')-Ib-cr (35/81, 43%) genes. Escherichia coli, the most commonly recovered species (51/83, 61%), was assigned mainly to the pandemic B2-O25b-ST131 group (39/51, 76%). Resistance transfer, which was studied in 20 randomly selected ESBL-E strains, was successful in 13 (13/20, 65%) isolates. In eight of these isolates (8/13, 62%), blaCTX-M-15 genes were found in incompatibility group FIb conjugative plasmids. We found one of the highest prevalence rates of faecal carriage of ESBL-E reported worldwide, highlighting the need to improve control of the distribution of antibiotics in limited-resource countries.

Integrons and gene cassettes in clinical isolates of co-trimoxazole-resistant Gram-negative bacteria.

Despite a trend of declining consumption, resistance to co-trimoxazole has increased during a 12-year period in Stockholm. The molecular background to this surprising development was investigated by using PCR to screen for integrons and specific resistance genes, followed by sequence analysis of selected integrons, in 105 clinical urinary isolates of Gram-negative bacteria selected partly for trimethoprim resistance. Sixty-five integrons of class 1 or 2 were detected in a subset of 59 isolates, and of these positive isolates, all but one were resistant to trimethoprim. However, 11 isolates were resistant to trimethoprim, but negative for integrons. Isolates positive for integrons were resistant to an average of 4.2 antibiotics, compared with 1.9 antibiotics for integron-negative isolates. Despite this, the only gene cassettes identified in 19 class 1 integrons analysed were dfr and aadA cassettes. Thus, only resistance to trimethoprim, streptomycin, spectinomycin and sulphonamides could be explained by the presence of integrons in these isolates. A new dfr gene, named dfrA22, was discovered as a single gene cassette in a class 1 integron. In addition, sulphonamide resistance in many isolates was caused by carriage of sul2, which has no known association with integrons. Resistance to co-trimoxazole and many other antibiotics was thus not accounted for fully by the presence of integrons in these isolates.

Different trends in antibiotic resistance rates at a university teaching hospital.

OBJECTIVES: To investigate long-term trends in antibiotic resistance of common bacterial species isolated at a university hospital and in its intensive care units (ICUs). METHODS: Levels of antibiotic resistance of common bacterial pathogens were investigated at the Karolinska Hospital during the 12-year period 1988-99. Resistance rates were analyzed for the entire hospital, as well as for ICUs combined. RESULTS: At the Karolinska Hospital, we found increased ciprofloxacin resistance among Escherichia coli isolates, from 0% in 1991 to 11% in 1999. In the ICUs, the corresponding increase was from 0% to 4.8% during the same period. Co-trimoxazole resistance levels increased from 7.5% to 14%, with lower levels for the ICUs. For ampicillin, cefuroxime, and gentamicin, the levels of resistance were similar in the whole hospital and in the ICUs. Among Pseudomonas aeruginosa isolates, imipenem resistance was higher in the ICUs. For ciprofloxacin, resistance increased from 2.5% in 1991 to 13% in 1999 in the whole hospital, with similar figures for the ICUs. CONCLUSION: The resistance rates at the Karolinska Hospital were still generally low, but were increasing for some antibiotic-microbe combinations. The results emphasize the importance of including all sectors of a hospital in resistance surveillance studies, and also the value of long surveillance periods.

[Posttraumatic true aneurysm of the left ventricle caused by a shotgun wound]. / Anévrysme vrai post-traumatique du ventricule gauche par charge de fusil de chasse.

An asymptomatic aneurysm of the left ventricle was discovered incidentally in a policeman aged 25, who had a history of a severe thoracic injury from a shotgun wound at the age of 15. Electrocardiography showed a transmural antero-lateral infarct; this was later confirmed at ventriculography. Coronary arteriography showed a narrowed anterior descending artery which crossed over the surface of the aneurysm. The cardiac status remained unchanged over an 8 year follow up period. The pathogenesis is discussed: a fold of contused myocardium, or immediate or late traumatic obstruction of the anterior descending artery, or both factors at the same time?