Despite step-down inhibitory avoidance procedures that have been widely implemented in rats and mice to study learning and emotion phenomena, performance of other species in these tasks has received less attention. The case of the Mongolian gerbil is of relevance considering the discrepancies in the parameters of the step-down protocols implemented, especially the wide range of foot-shock intensities (i.e., 0.4–4.0 mA), and the lack of information on long-term performance, extinction effects, and behavioral patterning during these tasks. Experiment 1 aimed to (a) characterize gerbils’ acquisition, extinction, and steady-state performance during a multisession (i.e., extended) step-down protocol adapted for implementation in a commercially-available behavioral package (Video Fear Conditioning System—MED Associates Fairfax, VT, USA), and (b) compare gerbils’ performance in this task with two shock intensities – 0.5 vs. 1.0 mA—considered in the low-to-mid range. Results indicated that the 1.0 mA protocol produced more reliable and clear evidence of avoidance learning, extinction, and reacquisition in terms of increments in freezing and on-platform time as well as suppression of platform descent. Experiment 2 aimed to (a) assess whether an alternate protocol consisting of a random delivery of foot shocks could replicate the effects of Experiment 1 and (b) characterize gerbils’ exploratory behavior during the step-down task (jumping, digging, rearing, and probing). Random shocks did not reproduce the effects observed with the first protocol. The data also indicated that a change from random to response-dependent shocks affects (a) the length of each visit to the platform, but not the frequency of platform descends or freezing time, and (b) the patterns of exploratory behavior, namely, suppression of digging and rearing, as well as increments in probing and jumping. Overall, the study demonstrated the feasibility of the extended step-down protocol for studying steady performance, extinction, and reacquisition of avoidance behavior in gerbils, which could be easily implemented in a commercially available system. The observation that 1.0 mA shocks produced a clear and consistent avoidance behavior suggests that implementation of higher intensities is unnecessary for reproducing aversive-conditioning effects in this species. The observed patterning of freezing, platform descents, and exploratory responses produced by the change from random to periodic shocks may relate to the active defensive system of the gerbil. Of special interest is the probing behavior, which could be interpreted as risk assessment and has not been reported in other rodent species exposed to step-down and similar tasks.

Patients with cancer have a higher risk of severe bacterial infections. This study aims to determine the frequency, susceptibility profiles, and resistance genes of bacterial species involved in bacteremia, as well as risk factors associated with mortality in cancer patients in Colombia. In this prospective multicenter cohort study of adult patients with cancer and bacteremia, susceptibility testing was performed and selected resistance genes were identified. A multivariate regression analysis was carried out for the identification of risk factors for mortality. In 195 patients, 206 microorganisms were isolated. Gram-negative bacteria were more frequently found, in 142 cases (68.9%): 67 Escherichia coli (32.5%), 36 Klebsiella pneumoniae (17.4%), and 21 Pseudomonas aeruginosa (10.1%), and 18 other Gram-negative isolates (8.7%). Staphylococcus aureus represented 12.4% (n = 25). Among the isolates, resistance to at least one antibiotic was identified in 63% of them. Genes coding for extended-spectrum beta-lactamases and carbapenemases, blaCTX-M and blaKPC, respectively, were commonly found. Mortality rate was 25.6% and it was lower in those with adequate empirical antibiotic treatment (22.0% vs. 45.2%, OR: 0.26, 95% CI: 0.1–0.63, in the multivariate model). In Colombia, in patients with cancer and bacteremia, bacteria have a high resistance profile to beta-lactams, with a high incidence of extended-spectrum beta-lactamases and carbapenemases. Adequate empirical treatment diminishes mortality, and empirical selection of treatment in this environment of high resistance is of key importance.

Background Infections are common complications in patients with cancer. Data on antimicrobial resistance is important to guide empirical antimicrobial therapy. However, resistance rates varies among different regions and countries and, in general, is higher in Latin America. There are limited data from these patients in this region. The aim of this work is to determine the frequency and antibiotic susceptibility profiles, as well as to identify the most frequent genes related to resistance, among microorganisms implicated in bacteremia in patients diagnosed with cancer Methods A cross-sectional multicenter study conducted in six hospitals in Colombia. An active laboratory search was carried out for adult patients with cancer and bacteremia. Data was obtained from the electronic medical records, and according to the resistance of the microorganisms, molecular tests were performed in a standardized way to identify genes related to methicillin-resistance, extended spectrum beta lactamases and carbapenemases. In addition, an exploratory multivariate analysis was performed using a logistic regression method to predict mortality Results 195 patients from 6 hospitals were included in the study. The clinical variables of the patients are described in Table 1. Gram-negative bacteria were more common and their resistance rates were high. The genes found in the different resistant bacterial isolates are described in Table 2; The main resistance genes identified were blaCTX-M and blaKPC, generating ESLB-type beta-lactamases and carbapenemases, respectively. 30 day-mortality was 26%, which is similar to other studies. Multivariate analysis showed that adequate antibiotic treatment (OR: 0.26 (95%CI 0.1-0.63)) and higher number of platelets (per 10,000, OR: 0.97 (95%CI 0.94-0.99)) were associated with survival. Mortality was associated with patients in palliative care (OR 3.51 (95%CI 1.05-12.04)). Conclusion Gram-negative bacilli are frequently found in patients with cancer and bacteremia. A high level of resistance was identified. The frequency of the genes identified varies from what has been described in other regions of the world. Appropriate and prompt treatment in these patient would improve the outcomes. Disclosures Jorge A. Cortés, MD, pfizer: Grant/Research Support Carlos Saavedra-Trujillo, MD, pfizer and merck: Grant/Research Support.

La diabetes mellitus es una enfermedad de gran prevalencia a nivel mundial que conlleva a muchas complicaciones, de las cuales las gastrointestinales son las mayormente olvidadas por el personal médico. Hasta el 22% de los pacientes con diabetes mellitus pueden tener diarrea y la causa de ello es multifactorial, pues incluye la neuropatía, efectos adversos de la terapia antidiabética, el aumento de la miocrobiota intestinal, entre otras.El tratamiento más efectivo es el control estricto de la glucemia; sin embargo, algunos medicamentos han sido utilizados con algún tipo de beneficio en estos pacientes. SummaryDiabetes mellitus is a highly prevalent disease worldwide leading to many complications of which gastrointestinal ones are largely neglected by physicians. Up to 22% of the patients suffering diabetes mellitus may have diarrhea, and this may be caused by multiple factors, including neuropathy, adverse effects of anti-diabetic therapy, intestinal miocrobiota increase, among other factors.The most effective treatment against these complications consists of a strict glycemic control, however, some medicines have been used in these patients achieving some benefits for them. Keywords IntroducciónLa diabetes es una enfermedad crónica que aparece cuando el páncreas no produce suficiente insulina o cuando los tejidos no utilizan eficazmente la insulina producida, incrementándose así los niveles de glucosa en sangre (1,2).Se estima que actualmente hay más de 347 millones de personas con diabetes mellitus (DM), convirtiéndose en el tercer problema de salud pública más importante en el mundo; datos en nuestro país reportan una prevalencia estimada del 7.5% (3). Esta enfermedad es responsable de más de 3 millones de muertes al año, el 80% se registran en países de ingresos bajos y medios como Colombia (4).La DM lleva consigo complicaciones a nivel de múltiples sistemas como el cardiovascular, neurológico, urinario y gastrointestinal, este último muchas veces olvidado por el personal médico, pero no menos importante, ocasionando aumento en la morbilidad e incluso en la mortalidad de los pacientes.