Effect of ampC derepression on cefepime MIC in Enterobacterales with chromosomally encoded inducible AmpC ß-lactamase.

OBJECTIVES: We aimed to evaluate the effect of ampC derepression on the cefepime MIC in different species of Enterobacterales with chromosomally encoded inducible AmpC ß-lactamase. METHODS: We analysed a large number of wild-type/mutant pairs (n = 1030 in total). Cefepime MICs were determined by broth microdilution according to EUCAST recommendations. RESULTS: ampC derepression led to increases in MIC by up to 10 dilutions, and significant increases by > 2 MIC dilutions were common across species (744/1030 mutants (72.2%) in total). Interestingly, the frequency of cefepime S→I/S→R transitions varied considerably between species: 66.3% in Enterobacter cloacae complex (167/252 mutants), 1.1% in Klebsiella aerogenes (2/180 mutants), 18.1% in Citrobacter freundii complex (50/277 mutants), 36.4% in Hafnia alvei (59/162 mutants), 19.0% in Providencia rettgeri (4/21 mutants), 22.9% in Providencia stuartii (11/48 mutants), 12.3% in Serratia marcescens (7/57 mutants), 20.0% in Serratia liquefaciens (6/30 mutants) and 0% in Morganella morganii (0/3 mutants). CONCLUSIONS: Our data show that the cefepime MIC is often increased by ampC derepression. However, the risk of S→I/S→R transition is dependent on the species.

[Isolated infarct of the corpus callosum: a misleading appearance]. / Infarctus isolé du corps calleux: un aspect trompeur.

We report here the case of an isolated corpus callosum infarct in a 48-year-old woman. Characteristics of this unusual condition are illustrated by multiple imaging modalities on follow-up. We discuss the pathophysiology of this rare entity and the more important differential diagnoses.

[Imaging of the coronary arteries with multi-channel CT: a pictorial assay]. / Illustration de l'anatomie coronaire en Scanner Volumique.

Advances in cardiac imaging with multidetector row CT allow new applications in the diagnosis of cardiac pathology. The purpose of this article is to illustrate the normal anatomy and main anatomical variants of the coronary arteries that can be detected with multi-channel CT. The images presented here were obtained using 4-channel and 16-channel multi-detector row CT units. Post-processing of CT imaging data was performed using: VRT, MPVR, and 2D curved MPR. Because of continuing technical advances, the use of CT imaging in the evaluation of cardiac disorders is likely to increase.

[MR imaging accuracy in the prediction of bone graft healing potential in scaphoid non-union]. / Valeur de l'IRM dans l'evaluation du potentiel de guérison des pseudarthroses du scaphoïde traitées par greffe osseuse.

PURPOSE: To determine the accuracy of MR imaging in predicting bone graft healing in patients with scaphoid non-union. MATERIAL AND METHODS: 21 patients with scaphoid non-union were examined with MR imaging prior to bone grafting (conventional bone graft in 14 cases and vascularized bone graft in 7 cases). The protocol included unenhanced and Gadolinium-enhanced sequences. Signal intensity and homogeneity of the proximal fragment was analysed by two independent radiologists. MRI findings were then correlated to the postoperative rate of union. RESULTS: Healing occurred in 17 cases and failed in 4 cases with a mean follow up of 14 months. Intraobserver agreement in MR reading was respectively 0.92 et 0.86. Interobserver agreement was 0.88. On Tl-wi, the proximal fragment was hyperintense in 1 case (with positive surgical result), heterogeneous low signal intensity in 7 cases (healing in n = 7) and homogeneous low signal intensity in 13 cases (healing in n = 9). On T2-wi, the proximal fragment was hypointense in 4 cases (healing in n = 3), homogeneous high signal in 5 cases (healing in n = 4) and heterogeneous high signal intensity in 12 cases (healing in n = 10). After Gadolinium injection, enhancement was homogeneous in 4 cases (healing in n = 4), heterogeneous in 8 cases (healing in n = 7) and absent in 9 cases (healing in n = 6). In the group with no enhancement, 5 patients were treated with vascularized bone graft (healing in n = 4) and 4 with conventional bone graft (healing in n = 2). CONCLUSION: The absence of enhancement of the proximal scaphoid fragment leads to poor surgical results except for vascularized bone graft.

[MR-arthrography: general principles and applications]. / L'arthro-IRM: principes et applications.

The recent approval by the French Ministry of Health of the use of intra-articular Gadolinium could promote the increasing use of MR-arthrography in France. Although useful in specific pathologies, it should not be overly prescribed and should be considered only if it provides a more accurate diagnosis than other less invasive techniques. The technical aspects and medico-legal implications of MR-arthrography as well as its various indications are reviewed in this article. There are three possible techniques: indirect MR-arthrography with IV Gadolinium injection, direct MR-arthrography with intra-articular Gadolinium injection and lastly, direct MR-arthrography with intra-articular injection of iodinated contrast media (or saline solution). Indirect MR-arthrography cannot be recommended because of insufficient contrast enhancement and the absence of joint filling. Conversely, direct MR-arthrography allows joint expansion which smooths out capsule and ligaments, better delineates articular surfaces and yields a homogeneous high intensity signal of the entire joint. Direct MR-arthrography with iodinated contrast media combines standard arthrography with conventional MRI. Direct MR-arthrography with intra-articular injection of dilute Gadolinium is associated with T1WI, usually of higher quality than T2WI, even though the latter remains part of the protocol. Although, the last two techniques yield higher image quality and are often performed for various articular pathologies, they should not be randomly carried out in the evaluation of joint pathology. However, they should be recommended as the first step in the diagnosis of painful shoulders or hips in young adults and athletes.

[Pleuropulmonary tularemia in a 63-year-old hunter in Germany]. / Pleuropulmonale Tularämie bei einem 63-jährigen Jäger in Deutschland.

HISTORY: A 63-year-old amateur hunter without relevant preexisting diseases presented with cough lasting for 4 weeks and B symptoms. INVESTIGATIONS: Radiography and ultrasonography showed a left-sided pleural effusion. Laboratory markers of infection were in normal range. A thoracocentesis was performed for diagnostic purposes. TREATMENT AND COURSE: Culture of Francisella tularensis spp. holarctica from pleural fluid led to the diagnosis of tularemia with unusual manifestation as an isolated one-sided pleuritis, confirmed by highly positive serology. The patient fully recovered on oral treatment with doxycycline. CONCLUSION: Due to its low prevalence in Germany and multiple possible clinical manifestations, the diagnosis of tularemia can be difficult. Hence, it is decisive to include tularemia in the differential diagnosis, especially if anamnestic or epidemiological evidence exists.

[Tularemia in Germany]. / Die Tularämie in Deutschland.

The bacterium Francisella tularensis is known for more than 100 years by now as the etiological agent of the disease tularemia, a zoonotic infection with a worldwide distribution in the Northern Hemisphere. The prevalence of tularemia shows a wide geographic variation, being comparably infrequent in Germany. Tularemia can present itself with multiple clinical manifestations including ulceroglandular, glandular, oropharyngeal, oculoglandular, respiratory and typhoidal forms. Due to the low prevalence and the unspecific symptomatology, a rapid diagnosis and early start of an effective therapy are rarely obtained. Thus, in this article we summarize important aspects concerning etiology, ecology and routes of transmission, recent epidemiologic situation, clinical picture, diagnostics and treatment of tularemia, focusing on the situation in Germany.