Real-world, multicentre evaluation of the incidence and risk factors for non-susceptible Stenotrophomonas maltophilia isolates.

BACKGROUND: Stenotrophomonas maltophilia is a cause of infection most commonly in the opportunistic host. Trimethoprim-sulfamethoxazole and levofloxacin are considered first-line treatment agents. With reports of increasing resistance to these first-line agents, it is important to determine risk factors associated with a non-susceptible isolate. METHODS: This was a real-world, multicentre, retrospective case-control study from five centres in the southeast United States evaluating S. maltophilia. The primary outcome was risk factors associated with non-susceptibility of S. maltophilia isolates to ≥1 antimicrobial agents. Secondary outcomes include incidence of S. maltophilia non-susceptibility, all-cause mortality, and 30-day readmission rates. RESULTS: There were 325 patients included in the study. For the primary outcome, the only factor associated with non-susceptibility per univariate analysis was isolation from urine culture (13.3% vs. 5.4%; P = 0.014), whereas the presence of mechanical ventilation (37.7% vs. 21.5%) and intensive care unit admission (35.3% vs. 18.4%) were associated with susceptibility (P < 0.001). For the secondary outcomes, non-susceptibility was present in 49% of isolates with 43 of 325 (13.2%), 53 of 324 (16.4%), and 105 of 172 (61%) to TMP-SMX, levofloxacin, and ceftazidime, respectively. Resistance to chloramphenicol and tigecycline was observed among 5/26 and 11/16 of tested isolates, respectively. Sixty-six patients (20%) experienced all-cause, inpatient mortality (18% susceptible vs. 23% non-susceptible; P = 0.280) and 44 patients (17%) were readmitted within 30 days of discharge (16% susceptible vs. 18% non-susceptible; P = 0.673). CONCLUSION: S. maltophilia non-susceptibility had a prevalence of ∼50% to at least one first-line or commonly used agent. More research is needed to delineate risk factors for non-susceptible isolates.

The inaccuracy of determining overcrowding status by using the national ED overcrowding study tool.

BACKGROUND: Emergency department (ED) crowding has become more common, and perceptions of crowding vary among different health care providers. The National Emergency Department Overcrowding Study (NEDOCS) tool is the most commonly used tool to estimate ED crowding but still uncertain of its reliability in different ED settings. OBJECTIVE: The objectives of this study are to determine the accuracy of using the NEDOCS tool to evaluate overcrowding in an extremely high-volume ED and assess the reliability and consistency of different providers' perceptions of ED crowding. MATERIAL AND METHODS: This was a 2-phase study. In phase 1, ED crowding was determined by the NEDOCS tool. The ED length of stay and number of patients who left without being seen were analyzed. In phase 2, a survey of simulated ED census scenarios was completed by different providers. The interrater and intrarater agreements of ED crowding were tested. RESULTS: In phase 1, the subject ED was determined to be overcrowded more than 75% of the time in which nearly 50% was rated as severely overcrowded by the NEDOCS tool. No statistically significant difference was found in terms of the average length of stay and the number of left without being seen patients under different crowding categories. In phase 2, 88 surveys were completed. A moderate level of agreement between health care providers was reached (κ = 0.5402, P < .0001). Test-retest reliability among providers was high (r = 0.8833, P = .0007). The strength of agreement between study groups and the NEDOCS was weak (κ = 0.3695, P < .001). CONCLUSION: Using the NEDOCS tool to determine ED crowding might be inaccurate in an extremely high-volume ED setting.

Spinal cord arteriovenous malformation in a toddler presenting with altered mental status and fever.

Central nervous system arteriovenous malformations (AVMs) are a rare cause of subarachnoid hemorrhage and neurologic deficits. About 90% of these lesions are supratentorial, with a smaller percentage occurring in the posterior fossa and an even smaller number found throughout the spine. Although spinal AVMs are uncommon, these disorders represent a treatable cause of significant morbidity in a young age group. We report a case of a T11-T12 spinal AVM in a 14-month-old girl presenting with low-grade fever and lethargy who was found to have subarachnoid hemorrhage on evaluation and describe a reasonable stepwise approach to these patients in the emergency department utilizing computed tomography, lumbar puncture, magnetic resonance imaging, and angiography.

Mapping out regions on the surface of the aspartate receptor that are essential for kinase activation.

The aspartate receptor of bacterial chemotaxis is representative of a large family of taxis receptors widespread in prokaryotes. The homodimeric receptor associates with cytoplasmic components to form a receptor-kinase signaling complex. Within this complex the receptor is known to directly contact the histidine kinase CheA, the coupling protein CheW, and other receptor dimers. However, the locations and extents of the contact regions on the receptor surface remain ambiguous. The present study applies the protein-interactions-by-cysteine-modification (PICM) method to map out surfaces on the aspartate receptor that are essential for kinase stimulation in the assembled receptor-kinase complex. The approach utilizes 52 engineered cysteine positions scattered over the surface of the receptor periplasmic and cytoplasmic domains. When the bulky, anionic probe 5-fluorescein-maleimide is coupled to these positions, large effects on receptor-mediated kinase stimulation are observed at eight cytoplasmic locations. By contrast, no large effects are observed for probe attachment at exposed positions in the periplasmic domain. The results indicate that essential receptor surface regions are located near the hairpin turn at the distal end of the cytoplasmic domain and in the cytoplasmic adaptation site region. These surface regions include the docking sites for CheA, CheW, and other receptor dimers, as well as surfaces that transmit information from the receptor adaptation sites to the kinase. Smaller effects observed in the cytoplasmic linker or HAMP region suggest this region may also play a role in kinase regulation. A comparison of the activity perturbations caused by a dianionic, bulky probe (5-fluorescein-maleimide), a zwitterionic, bulky probe (5-tetramethyl-rhodamine-maleimide), and a nonionic, smaller probe (N-ethyl-maleimide) reveals the roles of probe size and charge in generating the observed effects on kinase activity. Overall, the results indicate that interactions between the periplasmic domains of different receptor dimers are not required for kinase activation in the signaling complex. By contrast, the observed spatial distribution of protein contact surfaces on the cytoplasmic domain is consistent with both (i) distinct docking sites for cytoplasmic proteins and (ii) interactions between the cytoplasmic domains of different dimers to form a trimer-of-dimers.