Low yield of blood and wound cultures in patients with skin and soft-tissue infections.

BACKGROUND: Current guidelines recommend blood cultures in skin and soft-tissue infection (SSTI) patients only with signs of systemic toxicity and wound cultures for severe purulent infections. Our objectives were to determine: 1) blood and wound culture yields in patients admitted with SSTIs; 2) whether injection drug users (IDUs) and febrile patients had higher blood culture yields; and 3) whether blood and wound cultures grew organisms sensitive to typical SSTI empiric antibiotics. METHODS: We prospectively enrolled adult patients admitted from the ED with SSTIs at an urban hospital. We recorded patient characteristics, including IDU, comorbidities and temperatures, and followed admitted patients throughout their hospital course. RESULTS: Of 734 SSTI patients enrolled, 246 (33.5%) were admitted. Of 86 (35.0%) patients who had blood cultures, six had positive cultures (yield=7.0%; 95% confidence intervals [CIs] 3.2-14.4); 4 were methicillin sensitive Staphylococcus aureus (MSSA) and 2 were methicillin resistant (MRSA). Of 29 febrile patients, 1 had a positive culture (yield=3.5%; 95% CI 0.6-17.2). Of 101 admitted IDU patients, 46 (46%) received blood cultures, and 4 had positive cultures (yield=8.7%; 95% CI 3.4-20.3). Of 89 patients with purulent wounds, 44 (49.4%) patients had ED wound cultures. Thirteen had positive cultures (yield=29.6%; 95% CI 18.2-44.2%). Most were MRSA, MSSA, and group A Streptococcus species - all sensitive to Vancomycin. CONCLUSIONS: Febrile and IDU patients had low yields of blood cultures similar to yields in non-IDU and afebrile patients. All blood and wound culture species were adequately covered by currently recommended empiric antibiotic regimens.

Dysregulated Glycine Signaling Contributes to Increased Impulsivity during Protracted Alcohol Abstinence.

Persons with alcoholism who are abstinent exhibit persistent impairments in the capacity for response inhibition, and this form of impulsivity is significantly associated with heightened relapse risk. Brain-imaging studies implicate aberrant prefrontal cortical function in this behavioral pathology, although the underlying mechanisms are not understood. Here we present evidence that deficient activation of glycine and serine release in the ventral medial prefrontal cortex (vmPFC) contributes to increased motor impulsivity during protracted abstinence from long-term alcohol exposure. Levels of 12 neurotransmitters were monitored in the rat vmPFC during the performance of a challenging variant of the five-choice serial reaction time task (5-CSRTT) in which alcohol-exposed rats exhibit excessive premature responding. Following long-term ethanol exposure, rats showed blunted task-related recruitment of vmPFC glycine and serine release, and the loss of an inverse relationship between levels of these neurotransmitters and premature responding normally evident in alcohol-naive subjects. Intra-vmPFC administration of the glycine transport inhibitor ALX5407 prevented excessive premature responding by alcohol-exposed rats, and this was reliant on NMDA glycine site availability. Alcohol-exposed rats and controls did not differ in their premature responding and glycine and serine levels in vmPFC during the performance of the standard 5-CSRTT. Collectively, these findings provide novel insight into cortical neurochemical mechanisms contributing to increased impulsivity following long-term alcohol exposure and highlight the NMDA receptor coagonist site as a potential therapeutic target for increased impulsivity that may contribute to relapse risk.SIGNIFICANCE STATEMENT Persons with alcoholism demonstrate increased motor impulsivity during abstinence; however, the neuronal mechanisms underlying these behavioral effects remain unknown. Here, we took advantage of an animal model that shows deficiencies in inhibitory control following prolonged alcohol exposure to investigate the neurotransmitters that are potentially responsible for dysregulated motor impulsivity following long-term alcohol exposure. We found that increased motor impulsivity is associated with reduced recruitment of glycine and serine neurotransmitters in the ventromedial prefrontal cortex (vmPFC) cortex in rats following long-term alcohol exposure. Administration of glycine transport inhibitor ALX5407 in the vmPFC alleviated deficits in impulse control.