Re-evaluation of FDA-approved antibiotics with increased diagnostic accuracy for assessment of antimicrobial resistance

Accurate assessment of antibiotic susceptibility is critical for treatment of antimicrobial resistant (AMR) infections. Here, we examine whether antimicrobial susceptibility testing in media more physiologically representative of in vivo conditions improves prediction of clinical outcome relative to standard bacteriologic medium. This analysis reveals that ∼15% of minimum inhibitory concentration (MIC) values obtained in physiologic media predicted a change in susceptibility that crossed a clinical breakpoint used to categorize patient isolates as susceptible or resistant. The activities of antibiotics having discrepant results in different media were evaluated in murine sepsis models. Testing in cell culture medium improves the accuracy by which MIC assays predict in vivo efficacy. This analysis identifies several antibiotics for treatment of AMR infections that standard testing failed to identify and those that are ineffective despite indicated use by standard testing. Methods with increased diagnostic accuracy mitigate the AMR crisis via utilizing existing agents and optimizing drug discovery.

A broad-spectrum synthetic antibiotic that does not evoke bacterial resistance

BACKGROUND

Antimicrobial resistance (AMR) poses a critical threat to public health and disproportionately affects the health and well-being of persons in low-income and middle-income countries. Our aim was to identify synthetic antimicrobials termed conjugated oligoelectrolytes (COEs) that effectively treated AMR infections and whose structures could be readily modified to address current and anticipated patient needs.

METHODS

Fifteen chemical variants were synthesized that contain specific alterations to the COE modular structure, and each variant was evaluated for broad-spectrum antibacterial activity and for in vitro cytotoxicity in cultured mammalian cells. Antibiotic efficacy was analyzed in murine models of sepsis; in vivo toxicity was evaluated via a blinded study of mouse clinical signs as an outcome of drug treatment.

FINDINGS

We identified a compound, COE2-2hexyl, that displayed broad-spectrum antibacterial activity. This compound cured mice infected with clinical bacterial isolates derived from patients with refractory bacteremia and did not evoke bacterial resistance. COE2-2hexyl has specific effects on multiple membrane-associated functions (e.g., septation, motility, ATP synthesis, respiration, membrane permeability to small molecules) that may act together to negate bacterial cell viability and the evolution of drug-resistance. Disruption of these bacterial properties may occur through alteration of critical protein-protein or protein-lipid membrane interfaces-a mechanism of action distinct from many membrane disrupting antimicrobials or detergents that destabilize membranes to induce bacterial cell lysis.

INTERPRETATION

The ease of molecular design, synthesis and modular nature of COEs offer many advantages over conventional antimicrobials, making synthesis simple, scalable and affordable. These COE features enable the construction of a spectrum of compounds with the potential for development as a new versatile therapy for an imminent global health crisis.

FUNDING

U.S. Army Research Office, National Institute of Allergy and Infectious Diseases, and National Heart, Lung, and Blood Institute.

Establishment of blood glycosidase activities and their excursions in sepsis

Glycosidases are hydrolytic enzymes studied principally in the context of intracellular catabolism within the lysosome. Therefore, glycosidase activities are classically measured in experimentally acidified assay conditions reflecting their low pH optima. However, glycosidases are also present in the bloodstream where they may retain sufficient activity to participate in the regulation of glycoprotein half-lives, proteostasis, and disease pathogenesis. We have, herein, established at physiological pH 7.4 in blood plasma and sera the normal ranges of four major glycosidase activities essential for blood glycoprotein remodeling in healthy mice and humans. These activities included β-galactosidase, β-N-acetylglucosaminidase, α-mannosidase, and α-fucosidase. We have identified their origins to include the mammalian genes Glb1, HexB, Man2a1, and Fuca1. In experimental sepsis, excursions of glycosidase activities occurred with differences in host responses to discrete bacterial pathogens. Among similar excursions in human sepsis, the elevation of β-galactosidase activity was a prognostic indicator of increased likelihood of patient death.

Assessment of a Smartphone-Based Loop-Mediated Isothermal Amplification Assay for Detection of SARS-CoV-2 and Influenza Viruses

Importance

A critical need exists in low-income and middle-income countries for low-cost, low-tech, yet highly reliable and scalable testing for SARS-CoV-2 virus that is robust against circulating variants.

Objective

To assess whether a smartphone-based assay is suitable for SARS-CoV-2 and influenza virus testing without requiring specialized equipment, accessory devices, or custom reagents.

Design, Setting, and Participants

This cohort study enrolled 2 subgroups of participants (symptomatic and asymptomatic) at Santa Barbara Cottage Hospital. The symptomatic group consisted of 20 recruited patients who tested positive for SARS-CoV-2 with symptoms; 30 asymptomatic patients were recruited from the same community, through negative admission screening tests for SARS-CoV-2. The smartphone-based real-time loop-mediated isothermal amplification (smaRT-LAMP) was first optimized for analysis of human saliva samples spiked with either SARS-CoV-2 or influenza A or B virus; these results then were compared with those obtained by side-by-side analysis of spiked samples using the Centers for Disease Control and Prevention (CDC) criterion-standard reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) assay. Next, both assays were used to test for SARS-CoV-2 and influenza viruses present in blinded clinical saliva samples obtained from 50 hospitalized patients. Statistical analysis was performed from May to June 2021.

Exposures

Testing for SARS-CoV-2 and influenza A and B viruses.

Main Outcomes and Measures

SARS-CoV-2 and influenza infection status and quantitative viral load were determined.

Results

Among the 50 eligible participants with no prior SARS-CoV-2 infection included in the study, 29 were men. The mean age was 57 years (range, 21 to 93 years). SmaRT-LAMP exhibited 100% concordance (50 of 50 patient samples) with the CDC criterion-standard diagnostic for SARS-CoV-2 sensitivity (20 of 20 positive and 30 of 30 negative) and for quantitative detection of viral load. This platform also met the CDC criterion standard for detection of clinically similar influenza A and B viruses in spiked saliva samples (n = 20), and in saliva samples from hospitalized patients (50 of 50 negative). The smartphone-based LAMP assay was rapid (25 minutes), sensitive (1000 copies/mL), low-cost (<$7/test), and scalable (96 samples/phone).

Conclusions and Relevance

In this cohort study of saliva samples from patients, the smartphone-based LAMP assay detected SARS-CoV-2 infection and exhibited concordance with RT-qPCR tests. These findings suggest that this tool could be adapted in response to novel CoV-2 variants and other pathogens with pandemic potential including influenza and may be useful in settings with limited resources.

Use of pressure-regulated volume control in the first 48 hours of hospitalization of mechanically ventilated patients with sepsis or septic shock, with or without ARDS

Purpose

To evaluate the impact of pressure-regulated volume control (PRVC/VC+) use on delivered tidal volumes in patients with acute respiratory distress syndrome (ARDS) or at risk for ARDS.

Materials and methods

Retrospective study of mechanically ventilated adult patients with severe sepsis or septic shock.

Results

A total of 272 patients were divided into patients with recognized ARDS, patients without ARDS, and patients with unrecognized ARDS. Over 90% of patients were ventilated with PRVC on admission, resulting in delivered tidal volumes significantly higher than set tidal volumes among all groups at all time points, even after ARDS recognition (p < 0.001). Tidal volumes were lower for patients with pulmonary sepsis as compared to those with a nonpulmonary origin (p < 0.001).

Conclusions

Using PRVC promotes augmented delivered tidal volumes, often in excess of 6 mL/kg ideal body weight. Correct recognition of ARDS and having pulmonary sepsis improves compliance with low-stretch protocol ventilation.

Healthcare Event and Activity Logging

The health of patients in the intensive care unit (ICU) can change frequently and inexplicably. Crucial events and activities responsible for these changes often go unnoticed. This paper introduces healthcare event and action logging (HEAL) which automatically and unobtrusively monitors and reports on events and activities that occur in a medical ICU room. HEAL uses a multimodal distributed camera network to monitor and identify ICU activities and estimate sanitation-event qualifiers. At the core is a novel approach to infer person roles based on semantic interactions, a critical requirement in many healthcare settings where individuals' identities must not be identified. The proposed approach for activity representation identifies contextual aspects basis and estimates aspect weights for proper action representation and reconstruction. The flexibility of the proposed algorithms enables the identification of people roles by associating them with inferred interactions and detected activities. A fully working prototype system is developed, tested in a mock ICU room and then deployed in two ICU rooms at a community hospital, thus offering unique capabilities for data gathering and analytics. The proposed method achieves a role identification accuracy of 84% and a backtracking role identification of 79% for obscured roles using interaction and appearance features on real ICU data. Detailed experimental results are provided in the context of four event-sanitation qualifiers: clean, transmission, contamination, and unclean.

Characterization and testing of periodic mesoporous organosilicas as potential selective benzene adsorbents

The effects of surface imprinting on the adsorption and desorption properties of benzene- and diethylbenzene-bridged periodic mesoporous organosilicas (PMOs) acting as GC stationary-phase preconcentration sorbents for benzene and xylene were examined. Surface-imprinted and nonimprinted PMOs with diethylbenzene (DEB), benzene (BENZ), and ethane (BTSE) bridges and nonimprinted mesoporous silica (MCM-41) were prepared via well-established surfactant templating synthetic methods. The imprinted materials were synthesized using a surfactant demonstrated to produce trinitrotoluene (TNT) selective sorbents with increased adsorption capacity for cresol and 4-nitrophenol as well as TNT. Powder XRD and nitrogen sorption measurements revealed that all of the materials were mesoporous with the DEB materials having a random pore structure and lower surface area than the other materials which had ordered pore structures. Results for maximum uptake of benzene and p-xylene indicate a small but consistent positive effect on the adsorption of benzene and p-xylene due to surface imprinting. Comparing the surface area normalized uptakes (mg/m(2)) for materials having the same organic bridge with and without imprinting (DEB vs TDMI-DEB and BENZ vs TDMI-BENZ) shows that in seven of eight comparisons the imprinted analogue had a higher aromatic uptake. The imprinted samples showed higher weight normalized uptakes (mg/g) in five of eight cases. When used as a GC stationary phase, the organosilica materials yield more symmetrical chromatographic peaks and better separation than MCM-41, indicating superior trapping of BTX analytes, particularly at low concentrations. Additionally, these materials rapidly desorb the preconcentrated compounds.

Oxygen consumption in sepsis and septic shock

This review article examines the pathophysiology of septic shock, with special attention to the concept of supply-dependent consumption and the implications this concept has for therapy. Patients with septic shock require higher levels of oxygen delivery (DO2) to maintain aerobic metabolism. When DO2 is inadequate, peripheral tissues switch to anaerobic metabolism and oxygen consumption decreases. The lactic acidosis that occurs is a reasonable clinical marker of supply dependency and inadequate tissue perfusion. Maximizing DO2 is an important part of the hemodynamic resuscitation of patients with septic shock. To achieve this goal, intravascular volume must be restored and the myocardial depression associated with sepsis must be treated to optimize cardiac output. The normalization of arterial lactate concentration is a reasonable goal of resuscitative efforts.

Serum triiodothyronine values. Prognostic indicators of acute mortality due to Pneumocystis carinii pneumonia associated with the acquired immunodeficiency syndrome

A feasibility study was undertaken prospectively to identify early clinical and laboratory factors predictive of acute hospital mortality in patients with the acquired immunodeficiency syndrome and concurrent Pneumocystis carinii pneumonia. Twenty-six patients hospitalized with bronchoscopy-proved P carinii pneumonia were studied. Nineteen patients survived their episode of P carinii pneumonia, while 7 subjects did not. The only clinical factor associated with mortality was a history of a shorter duration of pulmonary symptoms. Univariate analysis showed decreased total CD8 cell count, total lymphocyte count, serum hemoglobin, serum albumin, total thyroxine, and total triiodothyronine values consistent with a poor outcome. Multivariate logistic regression analysis showed that the single best prognostic indicator of acute mortality appeared to be a total serum triiodothyronine value less than 0.70 nmol/L obtained early in the hospital course, and that the combination of serum triiodothyronine and hemoglobin values provided a better indication for survival. These preliminary observations would appear to justify the further exploration of serial serum triiodothyronine measurements as a potentially valuable prognostic indicator for the treatment of patients with acquired immunodeficiency syndrome infected with P carinii and possibly other intercurrent infectious illnesses.

Unique alterations of thyroid hormone indices in the acquired immunodeficiency syndrome (AIDS)

STUDY OBJECTIVE

To determine alterations in serum thyroid hormone indices in patients with human immunodeficiency virus (HIV) infection.

DESIGN

Prospective, single-blind study.

SETTING

Large metropolitan hospital where 20% of all patients with the acquired immunodeficiency syndrome (AIDS) in Los Angeles are treated.

PATIENTS

Twenty-six inpatients with bronchoscopy-proven Pneumocystis carinii pneumonia and AIDS. Outpatients included 10 persons seropositive for HIV, 10 with AIDS-related complex, and 10 with AIDS.

MAIN RESULTS

There were 19 survivors and 7 nonsurvivors of P. carinii infection. Serum triiodothyronine (T3) values generally remained normal until hospitalization, with nonsurvivors having lower values than survivors (0.56 +/- 0.1 nmol/L compared with 1.3 +/- 0.1 nmol/L, P less than 0.002, respectively). Reverse triiodothyronine (rT3) levels were low in persons with AIDS-related complex (0.21 +/- 0.02 nmol/L, P less than 0.001) and in AIDS outpatients (0.17 +/- 0.02 nmol/L, P less than 0.001). Normalization of rT3 occurred after patients were hospitalized (0.28 +/- 0.01 nmol/L). Serum thyroxine-binding globulin values rose with progression of HIV infection (seropositive, 369.7 +/- 18.1 nmol/L, P less than 0.005; AIDS-related complex, 419.1 +/- 37.0 nmol/L, P less than 0.005; AIDS, 423.3 +/- 31.9 nmol/L, P less than 0.005; survivors, 476.3 +/- 24.6 nmol/L, P less than 0.001), whereas nonsurvivors had normal values. All values are compared with normal values (T3, 2.3 +/- 0.04 nmol/L; rT3, 0.28 +/- 0.01 nmol/L; thyroxine-binding globulin, 288.2 +/- 6.9 nmol/L).

CONCLUSIONS

Infection with HIV produces unique alterations in thyroid function. A progressive decline in rT3 and elevation in thyroxine-binding globulin accompany advancing HIV infection. The persistence of a normal T3 despite progression of HIV infection may contribute to weight loss. A low serum T3 on admission correlates with mortality.