Aztreonam-Avibactam Susceptibility Testing Program for Metallo-Beta-Lactamase-Producing Enterobacterales in the Antibiotic Resistance Laboratory Network, March 2019 to December 2020.

Aztreonam-avibactam is a drug combination pending phase 3 clinical trials and is suggested for treatment of severe infections caused by metallo-beta-lactamase (MBL)-producing Enterobacterales by combining ceftazidime-avibactam and aztreonam. Beginning in 2019, four Antibiotic Resistance Laboratory Network regional laboratories offered aztreonam-avibactam susceptibility testing by broth microdilution. For 64 clinical isolates tested, the MIC50 and MIC90 values of aztreonam-avibactam were 0.5/4 µg/ml and 8/4 µg/ml, respectively. Aztreonam-avibactam displayed potent in vitro activity against the MBL-producing Enterobacterales tested.

Descriptive analysis of targeted carbapenemase genes and antibiotic susceptibility profiles among carbapenem-resistant Acinetobacter baumannii tested in the Antimicrobial Resistance Laboratory Network-United States, 2017-2020.

Acinetobacter baumannii is a Gram-negative bacillus that can cause severe and difficult-to-treat healthcare-associated infections. A. baumannii can harbor mobile genetic elements carrying genes that produce carbapenemase enzymes, further limiting therapeutic options for infections. In the United States, the Antimicrobial Resistance Laboratory Network (AR Lab Network) conducts sentinel surveillance of carbapenem-resistant Acinetobacter baumannii (CRAB). Participating clinical laboratories sent CRAB isolates to the AR Lab Network for characterization, including antimicrobial susceptibility testing and molecular detection of class A (Klebsiella pneumoniae carbapenemase), class B (Active-on-Imipenem, New Delhi metallo-ß-lactamase, and Verona integron-encoded metallo-ß-lactamase), and class D (Oxacillinase, blaOXA-23-like, blaOXA-24/40-like, blaOXA-48-like, and blaOXA-58-like) carbapenemase genes. During 2017‒2020, 6,026 CRAB isolates from 45 states were tested for targeted carbapenemase genes; 1% (64 of 5,481) of CRAB tested for targeted class A and class B genes were positive, but 83% (3,351 of 4,041) of CRAB tested for targeted class D genes were positive. The number of CRAB isolates carrying a class A or B gene increased from 2 of 312 (<1%) tested in 2017 to 26 of 1,708 (2%) tested in 2020. Eighty-three percent (2,355 of 2,846) of CRAB with at least one of the targeted carbapenemase genes and 54% (271 of 500) of CRAB without were categorized as extensively drug resistant; 95% (42 of 44) of isolates carrying more than one targeted gene had difficult-to-treat susceptibility profiles. CRAB isolates carrying targeted carbapenemase genes present an emerging public health threat in the United States, and their rapid detection is crucial to improving patient safety.IMPORTANCEThe Centers for Disease Control and Prevention has classified CRAB as an urgent public health threat. In this paper, we used a collection of >6,000 contemporary clinical isolates to evaluate the phenotypic and genotypic properties of CRAB detected in the United States. We describe the frequency of specific carbapenemase genes detected, antimicrobial susceptibility profiles, and the distribution of CRAB isolates categorized as multidrug resistant, extensively drug-resistant, or difficult to treat. We further discuss the proportion of isolates showing susceptibility to Food and Drug Administration-approved agents. Of note, 84% of CRAB tested harbored at least one class A, B, or D carbapenemase genes targeted for detection and 83% of these carbapenemase gene-positive CRAB were categorized as extensively drug resistant. Fifty-four percent of CRAB isolates without any of these carbapenemase genes detected were still extensively drug-resistant, indicating that infections caused by CRAB are highly resistant and pose a significant risk to patient safety regardless of the presence of one of these carbapenemase genes.

Performance evaluation of antibody-based point-of-care devices intended for the identification of immune responses to SARS-CoV-2.

The novel coronavirus outbreak caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) was first identified in December of 2019 in Wuhan, China. The local outbreak quickly rose to pandemic level that has spread to more than 188 countries with more than 19 million cases and 732,467 deaths worldwide. The current recommendation for testing is RT-PCR based tests of nasopharyngeal or alternatively nasal- and/or oropharyngeal swabs that detects infection with SARS-CoV-2 to diagnose acute infection. However, there is an urgent need for a quick and accurate antibody-based point-of-care test method to quickly identify evidence of SARS-CoV-2 infection among people who might be missed through active case finding and surveillance efforts. Serology tests measure the presence of antibodies in serum after infection. Here we compared the performance characteristics of 6 commercially available antibody-based point-of-care devices and their potential for identification of individuals infected at some time by SARS-CoV-2.