Prevalence of meticillin-resistant Staphylococcus pseudintermedius (MRSP) from skin and carriage sites of dogs after treatment of their meticillin-resistant or meticillin-sensitive staphylococcal pyoderma.

BACKGROUND: Meticillin-resistant staphylococci are significant pathogens in veterinary dermatology, yet longitudinal studies of the impact of routine antimicrobial therapy on emergence or resolution of resistance are lacking. OBJECTIVES: To determine the prevalence of meticillin-resistant staphylococci on skin and carriage sites in dogs with bacterial pyoderma and evaluate the prevalence of meticillin-resistant Staphylococcus pseudintermedius (MRSP) colonization after successful treatment of pyoderma. ANIMALS: One hundred and seventy-three dogs that presented to a dermatology referral service with pyoderma and 41 healthy control dogs. METHODS: Skin, nasal and rectal swabs for bacterial culture were collected at the time of referral and after clinical resolution of the pyoderma. Meticillin resistance was confirmed by demonstration of penicillin binding protein 2a antigen. RESULTS: Initially, skin cultures yielded MRSP in 70 (40.5%) dogs, meticillin-resistant Staphylococcus aureus (MRSA) in three (1.7%) and meticillin-resistant Staphylococcus schleiferi ssp. coagulans (MRSScoag) in five (2.9%). Samples collected from the nose and rectum (carriage sites) yielded MRSP in 59 (34.1%) dogs, MRSA in 11 (6.4%) and MRSScoag in seven (4.0%). One hundred and two dogs were available for follow-up cultures after clinical cure. Of 42 dogs initially diagnosed with MRSP pyoderma, MRSP was isolated at follow-up from skin in 19 (45.2%) and carriage sites in 20 (47.6%). Of 60 dogs that did not have MRSP pyoderma initially, MRSP was isolated post-treatment from the skin in 17 (28.3%), and MRSP from carriage sites increased from 7.8% (initially) to 26.7% (P = 0.0022). CONCLUSIONS AND CLINICAL IMPORTANCE: Colonization by MRSP often persists after resolution of MRSP pyoderma. Acquisition of MRSP during treatment appears to be common.

In vitro susceptibility testing of meticillin-resistant and meticillin-susceptible staphylococci to mupirocin and novobiocin.

Antimicrobials effective against meticillin-resistant staphylococci are limited. Mupirocin is a topical antimicrobial used to treat bacterial skin infections. Novobiocin is an oral antimicrobial approved for treatment of staphylococcal upper respiratory infections in dogs. This study reports the in vitro activity of mupirocin and novobiocin on meticillin-susceptible (MSS) and resistant staphylococci (MRS) from healthy dogs and dogs with superficial pyoderma. Staphylococci were isolated from skin swabs at four sites on healthy dogs and from lesions on dogs with superficial pyoderma. Staphylococci were identified by morphology and by catalase and coagulase testing. Speciation and susceptibility testing were performed by the Dade Microscan (W. Sacramento, CA, USA). Meticillin resistance was confirmed by an oxacillin screen plate. Novobiocin and mupirocin susceptibilities were tested by disc diffusion. Staphylococci were cultured from 61 healthy dogs (17 MRS and 44 MSS) and 30 dogs with pyoderma (15 MRS and 15 MSS), with higher proportions of MRS isolates in dogs with pyoderma (P=0.038; χ(2) test). For mupirocin, 79.5% (35 of 44) MSS and 82.3% (14 of 17) MRS isolates from healthy dogs, and 100% (15 of 15) MSS and 86.6% (13 of 15) MRS isolates from dogs with pyoderma were susceptible (MSS, P=0.094; MRS, P=1.0; Fisher's exact test). For novobiocin, 95.4% (42 of 44) MSS and 52.9% (nine of 17) MRS isolates from healthy dogs and 93.3% (14 of 15) MSS and 80% (12 of 15) MRS isolates from dogs with pyoderma were susceptible (MSS, P=1.0; MRS, P=0.148; Fisher's exact test).

Presentation outside office hours does not negatively influence treatment times for reperfusion therapy for acute ischemic stroke.

BACKGROUND: Treatment outside office hours has been associated with increased workflow times for intravenous thrombolysis (IVT) in acute ischemic stroke (AIS). Limited data suggest that this "off-hours effect" also exists for endovascular treatment (EVT). We investigated this phenomenon in a well-organized acute stroke care region in the Netherlands. METHODS: Retrospective, observational cohort study of consecutive patients with AIS who received reperfusion therapy in the Greater Amsterdam Area, consisting of 14 primary stroke centers and 1 comprehensive stroke center (IVT: 2009-2015, EVT: 2014-2017). Office hours were defined as presentation during weekdays between 8 AM and 5 PM, excluding National Festive days. Primary outcome was door-to-treatment time (door-to-needle [DNT] for IVT, door-to-groin [DGT] for EVT). For DGT, we used the door time of the first hospital. Other outcomes were in-hospital mortality, modified Rankin Scale (mRS) score at 90 days and symptomatic intracranial hemorrhage (sICH). We performed multivariable linear and logistic regression analyses and used multiple imputation to account for missing values. RESULTS: In total, 59% (2450/4161) and 61% (239/395) of patients treated with IVT and EVT, respectively, presented outside office hours. Median DNT was minimally longer outside office hours (32 vs. 30 min, p = 0.024, adjusted difference 2.5 min, 95% CI 0.7-4.2). Presentation outside office hours was not associated with a longer DGT (median 130 min for both groups, adjusted difference 7.0 min, 95% CI - 4.2 to 18.1). Clinical outcome and sICH rate also did not differ. CONCLUSION: Presentation outside office hours did not lead to clinically relevant treatment delays for reperfusion therapy in patients with AIS.

Monro-Kellie Hypothesis: Increase of Ventricular CSF Volume after Surgical Closure of a Spinal Dural Leak in Patients with Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: CSF loss in spontaneous intracranial hypotension disrupts a well-regulated equilibrium. We aimed to evaluate the volume shift between intracranial compartments in patients with spontaneous intracranial hypotension before and after surgical closure of the underlying spinal dural breach. MATERIALS AND METHODS: In total, 19 patients with spontaneous intracranial hypotension with a proved spinal CSF leak investigated at our institution between July 2014 and March 2017 (mean age, 41.8 years; 13 women) were included. Brain MR imaging-based volumetry at baseline and after surgery was performed with FreeSurfer. In addition, the spontaneous intracranial hypotension score, ranging from 0 to 9, with 0 indicating very low and 9 very high probability of spinal CSF loss, was calculated. RESULTS: Total mean ventricular CSF volume significantly increased from baseline (15.3 mL) to posttreatment MR imaging (18.0 mL), resulting in a mean absolute and relative difference, +2.7 mL and +18.8% (95% CI, +1.2 to +3.9 mL; P < .001). The change was apparent in the early follow-up (mean, 4 days). No significant change in mean total brain volume was observed (1136.9 versus 1133.1 mL, P = .58). The mean spontaneous intracranial hypotension score decreased from 6.9 ± 1.5 at baseline to 2.9 ± 1.5 postoperatively. CONCLUSIONS: Our study demonstrated a substantial increase in ventricular CSF volume in the early follow-up after surgical closure of the underlying spinal dural breach and may provide a causal link between spinal CSF loss and spontaneous intracranial hypotension. The concomitant decrease in the spontaneous intracranial hypotension score postoperatively implies the restoration of an equilibrium within the CSF compartment.

Spine MRI in Spontaneous Intracranial Hypotension for CSF Leak Detection: Nonsuperiority of Intrathecal Gadolinium to Heavily T2-Weighted Fat-Saturated Sequences.

BACKGROUND AND PURPOSE: Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension. MATERIALS AND METHODS: A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported. RESULTS: In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF (P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0). CONCLUSIONS: Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated.

The three dimensional structure of the islands of Calleja: a single heterogenous cell complex.

The islands of Calleja in the rat brain stain brilliantly and stand out clearly using the NADPH-diaphorase histochemical staining. The 3-D structure of the Islands of Calleja was mapped in sagittal sections of young adult (3 months) and aged (28 months) animals. Contours were determined using a camera lucida method, and transferred to a computer equipped with an image analyzing system. Alignment of the sections using fixed anatomical anchers revealed that the islands of Calleja were one continuous structure at both ages studied. The structures varied between animals, and there was a pronounced left-right difference in the individual rats.