Importance of the receiver's height for transmission studies in acoustic ecology.

In animal communication, the sound pressure level (SPL) of the acoustic signals has been studied in relation to various biological functions. Previous research reported that senders and receivers benefit from being at elevated positions. However, sometimes, researchers find contradictory results. Using a transmission experiment, we measured SPL of two acoustic stimuli: (i) white noise, and (ii) advertisement calls of the Iberian tree frog (Hyla molleri) at two different heights above ground level (0.05 and 0.75 m) and from six distances (1, 2, 4, 8, 16, and 32 m) from a loudspeaker. Calls of the Iberian tree frog have two spectral peaks centred at the frequencies of ca. 1 and 2 kHz. As expected, SPL decreased with distance, but following a distinct attenuation pattern across height above the ground and frequency. Our findings show that the ground effect may critically alter frequency attenuation and, therefore, signal composition and discrimination at the listener's location, even at low heights above the ground. We suggest that recording devices should be positioned at the same height that natural listeners are usually located in nature, to facilitate the replication and comparison of experiments in the field of acoustic ecology and, also, bioacoustics.

Stability of temocillin in outpatient parenteral antimicrobial therapy: is it a real option?

BACKGROUND: Temocillin is an interesting alternative to carbapenems for susceptible Enterobacteriaceae. Although its use in outpatient parenteral antimicrobial therapy (OPAT) programmes has generated interest, this has been hampered by the lack of stability data. OBJECTIVES: The purpose of the present study was to evaluate the physical and chemical stability of temocillin at the recommended dose for its use in OPAT programmes, contained in polypropylene infusion bags or polyisoprene elastomeric devices at different temperatures, and to describe a novel LC-MS/MS developed for the quantification of temocillin. METHODS: Temocillin daily dose (6 g) was diluted in 500 mL of 0.9% sodium chloride to obtain a final concentration of 12 g/L. This solution was stored at 4°C, 25°C, 32°C and 37°C for 72 h, both in polypropylene infusion bags and in polyisoprene elastomeric pumps. Physical and chemical stability were evaluated during 72 h after manufacturing. Solutions were considered stable if colour, clearness and pH remained unchanged and if the percentage of intact drug was ≥90%. RESULTS: Temocillin attained the chemical stability criterion of ≥90% of the original concentration for the whole experiment in both devices at 4°C, 25°C and 32°C. At 37°C, temocillin was stable for 24 h but its concentration dropped below 90% from that timepoint. No precipitation occurred and minor colour changes were observed. CONCLUSIONS: Temocillin is stable under OPAT conditions and it would be an appropriate candidate for the treatment of patients who can be discharged to complete therapy in an OPAT programme. For this study, an LC-MS/MS method was developed.

Effect of natural abiotic soil vibrations, rainfall and wind on anuran calling behavior: a test with captive-bred midwife toads (Alytes obstetricans).

Anurans are known to detect vibrations, but few studies explore relationships between vibrations and resultant behaviors. We studied the reaction of calling captive-bred male midwife toads (Alytes obstetricans) to the randomized playback of a vibrational crescendo stimulus train. We considered two sources of natural abiotic vibrational stimuli: rainfall and wind. Rainfall was expected to induce calling and wind was expected to inhibit it. Playback experiments with two synthetic tones (200 Hz and 300 Hz) tested the sensitivity to pure tones and could possibly reveal a hearing sensitivity trend between these frequencies. The toads did not increase call rate in response to rainfall vibrations and only one of the five wind stimulus levels caused a significant decrease in call rate. This limited response could be explained, because the tested toads came from a captive population, where emergence may not be mediated by rainfall vibrations. We found that A. obstetricans is highly sensitive to very low frequencies, which could explain the sensitivity observed to vibrational stimuli. Playback of a random crescendo stimulus train proves to be a valid approach for addressing behavioral questions. However, the use of a captive population may have been a limitation in the clarity of the results.

COVID-19 Vaccine Acceptance in Pregnancy.

OBJECTIVE: The purpose of the study is to evaluate the acceptance rate of the coronavirus disease 2019 (COVID-19) vaccine among pregnant women at our institution prior to recommendations by national organizations (American College of Obstetricians and Gynecologists/The Society for Maternal-Fetal Medicine) in July 2021 and to determine whether factors including health disparities are associated with acceptance. STUDY DESIGN: This is an Institutional Review Board exempt descriptive study. Anonymous surveys were administered from February 2021 to May 2021 to pregnant patients at Mount Sinai South Nassau's affiliated Maternal Fetal Medicine office. The survey was completed by 701 pregnant women. Descriptive statistics were calculated for the overall sample, as well as separately by group (acceptance versus declining/undecided about getting the COVID-19 vaccine). The two groups were compared using the chi-square test or Fisher's exact test and the two-sample t-test. Analysis was compared between two groups (patients who accepted the COVID-19 vaccine and people who declined/undecided about the vaccine). A result was considered statistically significant at the p < 0.05 level of significance. RESULTS: Of the 701 pregnant women who completed the survey, 96 patients accepted the vaccine. More pregnant women who were older accepted the COVID-19 vaccine compared with those who were younger (p = 0.0343). Pregnant women willing to get the flu vaccine and/or the Tdap vaccine in pregnancy were more likely to obtain the COVID-19 vaccine (p < 0.05). Pregnant patients who had household members willing to receive the COVID-19 vaccine sought to obtain the vaccine for themselves (p < 0.0001). Interestingly, pregnant women who had an underlying respiratory illness in the pregnancy were less likely to accept the COVID-19 vaccine than those who had either other or no medical problems (p < 0.05). CONCLUSION: There is a low rate of COVID-19 vaccine acceptance among pregnant women (13.69%). Efforts should be made to encourage the vaccine in this vulnerable population to protect them from the health risks of the COVID-19 virus. KEY POINTS: · COVID-19 vaccine acceptance rates in our population were 13.6%.. · Accepting Tdap and influenza vaccines increased the likelihood of accepting the COVID vaccine.. · Pregnant patients with respiratory illnesses were more likely to decline the COVID vaccine..

Cyber-Physical System for Environmental Monitoring Based on Deep Learning.

Cyber-physical systems (CPS) constitute a promising paradigm that could fit various applications. Monitoring based on the Internet of Things (IoT) has become a research area with new challenges in which to extract valuable information. This paper proposes a deep learning classification sound system for execution over CPS. This system is based on convolutional neural networks (CNNs) and is focused on the different types of vocalization of two species of anurans. CNNs, in conjunction with the use of mel-spectrograms for sounds, are shown to be an adequate tool for the classification of environmental sounds. The classification results obtained are excellent (97.53% overall accuracy) and can be considered a very promising use of the system for classifying other biological acoustic targets as well as analyzing biodiversity indices in the natural environment. The paper concludes by observing that the execution of this type of CNN, involving low-cost and reduced computing resources, are feasible for monitoring extensive natural areas. The use of CPS enables flexible and dynamic configuration and deployment of new CNN updates over remote IoT nodes.

Is Once-Daily High-Dose Ceftriaxone plus Ampicillin an Alternative for Enterococcus faecalis Infective Endocarditis in Outpatient Parenteral Antibiotic Therapy Programs?

Ceftriaxone administered as once-daily high-dose short infusion combined with ampicillin has been proposed for the treatment of Enterococcus faecalis infective endocarditis in outpatient parenteral antibiotic therapy programs (OPAT). This combination requires synergistic activity, but the attainment of ceftriaxone synergic concentration (Cs) with the regimen proposed for OPAT has not been studied. This phase II pharmacokinetic study enrolled healthy adult volunteers who underwent two sequential treatment phases. During phase A, volunteers received 2 g of ceftriaxone each 12 h during 24 h followed by a 7-day wash-out. Then the participants received phase B, which consisted of a single dose of 4 g of ceftriaxone. Throughout both phases, each volunteer underwent intensive pharmacokinetic (PK) sampling over 24 h. Ceftriaxone total and unbound concentrations were measured. Twelve participants were enrolled and completed both phases. Mean ceftriaxone total and free concentrations 24 h after the administration of 2 g each 12 h were 86.44 ± 25.90 mg/liter and 3.59 ± 1.35 mg/liter, respectively, and after the 4-g single dose were 34.60 ± 11.16 mg/liter and 1.40 ± 0.62 mg/liter, respectively. Only 3 (25%) patients in phase A maintained unbound plasma concentrations superior to the suggested Cs = 5 mg/liter during 24 h, and none (0%) in phase B. No grade 3 to 4 adverse events or laboratory abnormalities were observed. Ceftriaxone optimal exposure combined with ampicillin to achieve maximal synergistic activity against E. faecalis required for the treatment of infective endocarditis remains unknown. However, the administration of a single daily dose of 4 g of ceftriaxone implies a reduction in the time of exposure to the proposed Cs. (This study has been registered in the European Union Drug Regulating Authorities Clinical Trials [EudraCT] database under identifier 2017-003127-29.).

Changes in melanocyte RNA and DNA methylation favour pheomelanin synthesis and may avoid systemic oxidative stress after dietary cysteine supplementation in birds.

Cysteine plays essential biological roles, but excessive amounts produce cellular oxidative stress. Cysteine metabolism is mainly mediated by the enzymes cysteine dioxygenase and γ-glutamylcysteine synthetase, respectively coded by the genes CDO1 and GCLC. Here we test a new hypothesis posing that the synthesis of the pigment pheomelanin also contributes to cysteine homeostasis in melanocytes, where cysteine can enter the pheomelanogenesis pathway. We conducted an experiment with the Eurasian nuthatch Sitta europaea, a bird producing large amounts of pheomelanin for feather pigmentation, to investigate if melanocytes show epigenetic lability under exposure to excess cysteine. We increased systemic cysteine levels in nuthatches by supplementing them with dietary cysteine during growth. In feather melanocytes this led to the downregulation of genes involved in intracellular cysteine metabolism (GCLC), cysteine transport to the cytosol from the extracellular medium (Slc7a11) and from melanosomes (CTNS), and regulation of tyrosinase activity (MC1R and ASIP). These changes were mediated by increases in DNA m5 C in all genes except Slc7a11, which experienced RNA m6 A depletion. Birds supplemented with cysteine synthesized more pheomelanin than controls, but did not suffer higher systemic oxidative stress. These results suggest that excess cysteine activates an epigenetic mechanism that favours pheomelanin synthesis and may protect against oxidative stress.

Brca1 deficiency causes bone marrow failure and spontaneous hematologic malignancies in mice.

BRCA1 is critical for maintenance of genomic stability and interacts directly with several proteins that regulate hematopoietic stem cell function and are part of the Fanconi anemia (FA) double-strand break DNA repair pathway. The effects of complete BRCA1 deficiency on bone marrow (BM) function are unknown. To test the hypothesis that Brca1 is essential in hematopoiesis, we developed a conditional mouse model with Mx1-Cre-mediated Brca1 deletion. Mice lacking Brca1 in the BM have baseline cytopenias and develop spontaneous bone marrow failure or diverse hematologic malignancies by 6 months of age. Brca1(-/-) BM cells have a reduced capacity to form hematopoietic colonies in vitro and to reconstitute hematopoiesis in irradiated recipients, consistent with a hematopoietic progenitor functional defect. Brca1(-/-) BM cells also show FA-like hypersensitivity to the DNA crosslinking agent mitomycin C, and karyotypes feature genomic instability. Taken together, our results show that loss of Brca1 in murine BM causes hematopoietic defects similar to those seen in people with FA, which provides strong evidence that Brca1 is critical for normal hematopoiesis and that Brca1 is a bona fide FA-like gene.

Identifying Inherited and Acquired Genetic Factors Involved in Poor Stem Cell Mobilization and Donor-Derived Malignancy.

Analysis of the clinical characteristics of hematopoietic stem cell transplant (HSCT) donors has proven beneficial for identifying cases of heritable hematopoietic disorders. This study examines poor peripheral blood hematopoietic stem cell mobilization after granulocyte colony-stimulating factor administration among 328 donors as a potential marker for suspected familial predisposition to myeloid malignancies. Here, we present data comparing the clinical characteristics of poor-mobilizing versus nonpoor-mobilizing donors and the results of panel-based sequencing of hematopoietic genes in poor-mobilizing donors. From this analysis, we identified a novel case of a donor-derived myelodysplastic syndrome in an HSCT recipient that is consistent with clonal evolution of TET2-mutated clonal hematopoiesis of indeterminate potential (CHIP) within the donor. This study demonstrates the potential risk of using hematopoietic stem cells from a donor with CHIP and raises the question of whether there should be increased screening measures to identify such donors.

Inherited mutations in cancer susceptibility genes are common among survivors of breast cancer who develop therapy-related leukemia.

BACKGROUND: Risk factors for the development of therapy-related leukemia (TRL), an often lethal late complication of cytotoxic therapy, remain poorly understood and may differ for survivors of different malignancies. Survivors of breast cancer (BC) now account for the majority of TRL cases, making the study of TRL risk factors in this population a priority. METHODS: Subjects with TRL after cytotoxic therapy for a primary BC were identified from the TRL registry at The University of Chicago. Those with an available germline DNA sample were screened with a comprehensive gene panel covering known inherited BC susceptibility genes. Clinical and TRL characteristics of all subjects and those with identified germline mutations were described. RESULTS: Nineteen of 88 survivors of BC with TRL (22%) had an additional primary cancer and 40 of the 70 survivors with an available family history (57%) had a close relative with breast, ovarian, or pancreatic cancer. Of the 47 subjects with available DNA, 10 (21%) were found to carry a deleterious inherited mutation in BRCA1 (3 subjects; 6%), BRCA2 (2 subjects; 4%), TP53 (tumor protein p53) (3 subjects; 6%), CHEK2 (checkpoint kinase 2) (1 subject; 2%), and PALB2 (partner and localizer of BRCA2) (1 subject; 2%). CONCLUSIONS: Survivors of BC with TRL have personal and family histories suggestive of inherited cancer susceptibility and frequently carry germline mutations in BC susceptibility genes. The data from the current study support the role of these genes in TRL risk and suggest that long-term follow-up studies of women with germline mutations who are treated for BC and functional studies of the effects of heterozygous mutations in these genes on bone marrow function after cytotoxic exposures are warranted. Cancer 2016;122:304-311. © 2015 American Cancer Society.

Inherited predisposition to breast cancer among African American women.

African Americans have a disproportionate burden of aggressive young-onset breast cancer. Genomic testing for inherited predisposition to breast cancer is increasingly common in clinical practice, but comprehensive mutation profiles remain unknown for most minority populations. We evaluated 289 patients who self-identified as African American with primary invasive breast cancer and with personal or family cancer history or tumor characteristics associated with high genetic risk for all classes of germline mutations in known breast cancer susceptibility genes using a validated targeted capture and multiplex sequencing approach. Sixty-eight damaging germline mutations were identified in 65 (22 %, 95 % CI 18-28 %) of the 289 subjects. Proportions of patients with unequivocally damaging mutations in a breast cancer gene were 26 % (47/180; 95 % confident interval [CI] 20-33 %) of those with breast cancer diagnosis before age 45; 25 % (26/103; 95 % CI 17-35 %) of those with triple-negative breast cancer (TNBC); 29 % (45/156; 95 % CI 22-37 %) of those with a first or second degree relative with breast cancer before age 60 or with ovarian cancer; and 57 % (4/7; 95 % CI 18-90 %) of those with both breast and ovarian cancer. Of patients with mutations, 80 % (52/65) carried mutations in BRCA1 and BRCA2 genes and 20 % (13/65) carried mutations in PALB2, CHEK2, BARD1, ATM, PTEN, or TP53. The mutational allelic spectrum was highly heterogeneous, with 57 different mutations in 65 patients. Of patients meeting selection criteria other than family history (i.e., with young age at diagnosis or TNBC), 48 % (64/133) had very limited information about the history of cancer in previous generations of their families. Mutations in BRCA1 and BRCA2 or another breast cancer gene occur in one in four African American breast cancer patients with early onset disease, family history of breast or ovarian cancer, or TNBC. Each of these criteria defines patients who would benefit from genomic testing and novel therapies targeting DNA repair pathways.

Potentiation of the Antimicrobial Effect of Oxytetracycline Combined with Cinnamon, Clove, Oregano, and Red Thyme Essential Oils against MDR Salmonella enterica Strains.

Tetracyclines have a high resistance percentage in Salmonella spp. of both human and animal origin. Essential oils, such as cinnamon (Cinnamomum zeylanicum), clove (Eugenia caryophyllata), oregano (Origanum vulgare), and red thyme (Thymus zygis), have shown bactericidal activity against this bacterium. However, in many cases, the minimum inhibitory concentration (MIC) exceeds the cytotoxicity limits. The objective of this study was to assess the in vitro efficacy of combining oxytetracycline with essential these oils against field multidrug-resistant (MDR) Salmonella enterica strains. The MIC of each product was determined using the broth microdilution method. The interaction was evaluated using the checkerboard method, by means of the fractional inhibitory concentration index (FICindex) determination. The results showed a positive interaction (synergy and additivity) between oxytetracycline and the four oils tested, resulting in a reduction in both products' MICs by 2 to 4 times their initial value, in the case of oils, and by 2 to 1024 times in the case of the antibiotic. The combination of oxytetracycline and cinnamon achieved the best results (FICindex 0.5), with a decrease in the antibiotic effective concentration to below the sensitivity threshold (MIC of the combined oxytetracycline 0.5 µg/mL). There was no antagonistic effect in any case, although differences in response were observed depending on the bacterial strain. The results of this study suggest that combining oxytetracycline with cinnamon oil could be an effective alternative for controlling tetracycline-resistant strains of Salmonella. However, its individual use should be further evaluated through in vitro susceptibility tests.

A case of fatal monkeypox infection: necropsy and molecular findings, with some considerations related to clinical management.

OBJECTIVE: Human monkeypox (mpox) is usually self-limited infection; however, rising data show a worse outcome in patients with impaired immune status, particularly those co-infected with HIV [Mitjà O, Alemany A, Marks M, Lezama Mora JI, Rodríguez-Aldama JC, Torres Silva MS et al. Mpox in people with advanced HIV infection: A global case series. Lancet. 2023; 401:939-49. DOI:https://doi.org/10.1016/S0140-6736(23)00273-8] [Govind A, Lazarte SM, Kitchell E, Chow JY, Estelle CD, Fixsen E et al. Severe mpox infections in people with uncontrolled human immunodeficiency virus (HIV). Clin Infect Dis. 2023; 76:1843-6. DOI:https://doi.org/10.1093/cid/ciad052]. METHODS: We report the clinical, pathological, and molecular study of a patient with mpox infection and a late HIV diagnosis, with fatal outcome. RESULTS: Necropsy revealed visceral spread of mpox. Mpox virus was sequenced twice during the admission, uncovering an emerging mutation near a genomic region where mutations associated with tecovirimat resistance have been documented. DISCUSSION: Monkeypox can manifest as an opportunistic infection in individuals with advanced HIV-associated immunosuppression.

A new algorithm DEtectS critical Congenital Heart Disease at different altitudes: ANDES-CHD study.

BACKGROUND: Neonatal pulse oximetry screening (POS) algorithms for critical congenital heart disease (CCHD) have contributed towards decreasing neonatal mortality but cannot be applied at high altitudes. New POS algorithms at high altitudes are needed. METHODS: This observational, prospective study included newborns born at different altitudes from 0 to 4380 meters above the sea level in Peru. Healthy newborns underwent neonatal preductal and postductal oximetry, echocardiography and telephonic follow-up up to 12 months of age. Newborns with CCHD underwent preductal and postductal oximetry at the time of telemedicine evaluation while located at the high-altitude hospital where they were born, and their diagnoses were confirmed with echocardiography locally or after arriving to the referral center. Two new algorithms were designed using clinically accepted neonatal oximetry cutoffs or the 5th and 10th percentiles for preductal and postductal oximetry values. RESULTS: A total of 502 healthy newborns and 15 newborns with CCHD were enrolled. Echocardiography and telephonic follow-up were completed in 227 (45%) and 330 healthy newborns (65%), respectively. The algorithm based on clinically accepted cutoffs had a sensitivity of 92%, specificity of 73% and false positive rate of 27% The algorithm based on the 5th and 10th percentiles had a sensitivity of 80%, specificity of 88% and false positive rate of 12%. CONCLUSIONS: Two algorithms that detect CCHD at different altitudes had adequate performance but high false positive rates.

Salmonella and Salmonellosis: An Update on Public Health Implications and Control Strategies.

Salmonellosis is globally recognized as one of the leading causes of acute human bacterial gastroenteritis resulting from the consumption of animal-derived products, particularly those derived from the poultry and pig industry. Salmonella spp. is generally associated with self-limiting gastrointestinal symptoms, lasting between 2 and 7 days, which can vary from mild to severe. The bacteria can also spread in the bloodstream, causing sepsis and requiring effective antimicrobial therapy; however, sepsis rarely occurs. Salmonellosis control strategies are based on two fundamental aspects: (a) the reduction of prevalence levels in animals by means of health, biosecurity, or food strategies and (b) protection against infection in humans. At the food chain level, the prevention of salmonellosis requires a comprehensive approach at farm, manufacturing, distribution, and consumer levels. Proper handling of food, avoiding cross-contamination, and thorough cooking can reduce the risk and ensure the safety of food. Efforts to reduce transmission of Salmonella by food and other routes must be implemented using a One Health approach. Therefore, in this review we provide an update on Salmonella, one of the main zoonotic pathogens, emphasizing its relationship with animal and public health. We carry out a review on different topics about Salmonella and salmonellosis, with a special emphasis on epidemiology and public health, microbial behavior along the food chain, predictive microbiology principles, antimicrobial resistance, and control strategies.

Treatment of Enterococcus faecalis Infective Endocarditis: A Continuing Challenge.

Today, Enterococcus faecalis is one of the main causes of infective endocarditis in the world, generally affecting an elderly and fragile population, with a high mortality rate. Enterococci are partially resistant to many commonly used antimicrobial agents such as penicillin and ampicillin, as well as high-level resistance to most cephalosporins and sometimes carbapenems, because of low-affinity penicillin-binding proteins, that lead to an unacceptable number of therapeutic failures with monotherapy. For many years, the synergistic combination of penicillins and aminoglycosides has been the cornerstone of treatment, but the emergence of strains with high resistance to aminoglycosides led to the search for new alternatives, like dual beta-lactam therapy. The development of multi-drug resistant strains of Enterococcus faecium is a matter of considerable concern due to its probable spread to E. faecalis and have necessitated the search of new guidelines with the combination of daptomycin, fosfomycin or tigecycline. Some of them have scarce clinical experience and others are still under investigation and will be analyzed in this review. In addition, the need for prolonged treatment (6-8 weeks) to avoid relapses has forced to the consideration of other viable options as outpatient parenteral strategies, long-acting administrations with the new lipoglycopeptides (dalbavancin or oritavancin), and sequential oral treatments, which will also be discussed.

[Epidemiology of leptospirosis in the wetlands of Southern Spain]. / Epidemiología de la leptospirosis en los humedales del sur de España.

OBJECTIVE: To find out whether the leptospirosis incidence rate among red swamp crayfish collectors in the harvesting season is higher than in the general population, and to identify risk factors and assess the direct and indirect health costs associated with leptospirosis seroconversion. METHOD: This study was carried out between 1 July 2017 and 31 March 2018 in the municipality of Isla Mayor (Seville, Spain). It took the form of a prospective cohort study (exposed population: swamp crayfish collectors; non-exposed population: general population). The population was invited to take part in a prevalence study to be conducted using the ELISA qualitative technique, and informed consent was obtained from those who agreed. Negative serology cases were then included in the cohort study. Both cohorts were monitored clinically and symptomatic cases were serology tested. A second serum sample was taken from the swamp crayfish collectors at the end of the monitoring period to detect asymptomatic cases. Serovars were confirmed by microscopic agglutination testing. A bivariate descriptive analysis was carried out and cumulative incidence and relative risk were calculated, with positive serology being taken as the dependent variable. RESULTS: A total of 278 people were included in the study, of whom 92 made up the swamp crayfish collectors cohort and 186 the general population cohort. Women made up 46.8% of the sample, but only 29.3% of the collectors cohort. The mean age was 45.1 (±16.4) years. Nine cases of seroconversion were detected: eight among swamp crayfish collectors and one in the general population. Overall cumulative incidence was therefore 3.2%: 8.7% in the exposed group and 0.5% in the non-exposed group. Relative risk was 16.2% (95% confidence interval: 2.1-127.4). The total cost of medical assistance and illness-related losses associated with leptospirosis was 1568€/case. CONCLUSIONS: Leptospirosis in Isla Mayor is strongly associated with red swamp crayfish collecting. It's incidence here is much higher than that reported in studies published in other countries.

Stability of Ampicillin plus Ceftriaxone Combined in Elastomeric Infusion Devices for Outpatient Parenteral Antimicrobial Therapy.

Currently, ampicillin plus ceftriaxone (AC) is one of the preferred treatments for Enterococcus faecalis infective endocarditis. However, there is a lack of stability data for the combination of both drugs in elastomeric devices, so the inclusion of AC in Outpatient Parenteral Antimicrobial Therapy (OPAT) programs is challenging. The objective of the study was to determine the stability of AC in elastomeric pumps when stored at 8 ± 2 °C, 25 ± 2 °C, 30 ± 2 °C and 37 ± 2 °C using LC-MS/MS. The combination was diluted in 0.9% sodium chloride and the final concentrations were ampicillin 24 g/L plus ceftriaxone 8 g/L. Physical and chemical stability were evaluated at 12, 20, 24, 36 and 48 h after preparation. Stability was met at each time point if the percentage of intact drug was ≥90% of its respective baseline concentration and color and clearness remained unchanged. The drug combination was stable for 48 h when it was kept at 8 ± 2 °C. At 25 ± 2 °C and 30 ± 2 °C, they were stable for 24 h of storage. At 37 ± 2 °C, the stability criterion was not met at any time point. These results prove that AC could be included in OPAT programs using elastomeric infusion devices for the treatment of E. faecalis infections.