Mira, Portia

ABSTRACT Background Mycobacterium genavense is a rare opportunistic non-tuberculous mycobacterium primarily reported in advanced human immunodeficiency virus infection. Case Summary A 70-year-old woman with systemic lupus erythematosus developed progressive abdominal pain, weight loss, and mesenteric lymphadenitis repeatedly responsive to corticosteroids. Endoscopic biopsies revealed abundant acid-fast bacilli, and molecular testing confirmed the presence of M. genavense . Treatment with azithromycin, ethambutol, and rifabutin led to gradual recovery. Conclusion Steroid-responsive mesenteric inflammation in immunocompromised patients should prompt evaluation for infection, including mycobacteria and other culture-negative microorganisms using molecular diagnostics. This case report highlights the importance of plasma microbial cell-free DNA assays in the identification of fastidious organisms, like M. genavense , and, in some cases, serial testing may be useful to monitor treatment response.

Background: There are limited oral treatment options available for resistant Gram-negative bacterial (GNB) infections. Minocycline, a second-generation tetracycline antibiotic, offers good bioavailability and broad-spectrum coverage that may be an option for GNB infections. Methods: We conducted a retrospective review of minocycline susceptibility testing performed on GNB isolates at the Mayo Clinic reference lab between 2013 and 2022. Minocycline susceptibility was evaluated with a focus on difficult-to-treat organisms and relevant anatomic source. Organisms included resistant isolates of Escherichia coli and Klebsiella pneumoniae ; high-risk ampC-derepressors, including Citrobacter freundii, Enterobacter cloacae, and K. aerogenes; and clinically challenging non-Enterobacterales, Acinetobacter species, Achromobacter species, and Stenotrophomonas maltophilia . Results: Of 217,206 GNB isolates, 18,148 Enterobacterales (EB) and 8,190 non- Enterobacter isolates were tested for minocycline susceptibility. Of these, 80% of all EB and 92% of non-EB isolates were susceptible. Among E. coli isolates with ceftriaxone, ciprofloxacin, meropenem, or multidrug resistance, minocycline susceptibility was 78%, 76%, 70%, and 70.9%, respectively. Among the K. pneumoniae isolates with ceftriaxone, ciprofloxacin, meropenem, or multidrug resistance, minocycline susceptibility was 46%, 38%, 37%, and 39.3%, respectively. 85% of C. freundii , 81% of E. cloacae, and 85% of K. aerogenes isolates were susceptible to Minocycline. 83.5% of Achromobacter species isolates, 66% of Acinetobacter species isolates, and 99.1% of S. maltophilia isolates were susceptible. Conclusions: Our study reports the largest collection of minocycline susceptibility findings in GNB. Minocycline showed in vitro activity against many difficult-to-treat GNB isolates, including ceftriaxone- and multidrug-resistant E. coli and some K. pneumoniae isolates, common Amp-C-producing species, and non-fermenting GNB, including Stenotrophomonas , Acinetobacter , and Achromobacter .

Abstract Background New insights into community-acquired pleural infection microbiology may enable development of more rapid and accessible diagnostics that can streamline treatment. This study systematically compared molecular approaches for pathogen detection in pleural fluid from patients with such infections. Considering the need for rapid results with minimum hands-on time and test complexity, off-label use of the cassette-based, random-access BIOFIRE Joint Infection Panel (BF-JIP, bioMérieux) with and without supplementary in-house polymerase chain reaction (PCR) assays was evaluated. Methods Pleural fluids from 162 subjects from the Mayo Clinic (Rochester, Minnesota) and Haukeland University Hospital (Bergen, Norway), where molecular tests are routinely used for analyzing pleural fluid, were studied. The performance of the BF-JIP was compared to 16S rRNA gene PCR followed by Sanger and/or next-generation sequencing (16S rRNA gene PCR/sequencing), an in-house PCR panel specifically designed for pleural space infections, and culture. Results The BF-JIP supplemented with 3 in-house PCR assays targeting Fusobacterium nucleatum group, Streptococcus intermedius/constellatus, and Aggregatibacter aphrophilus detected 96.8% of pleural infections, providing complete microbial profiles in 70.1%. In comparison, the detection rate of 16S rRNA gene PCR/sequencing was 92.2%, providing complete microbial profiles in 87.0%. Culture detected bacteria in only 31.9% of pleural fluids, providing complete microbial profiles in 15.3%. Conclusions These results underscore the importance of molecular approaches in diagnosing pleural space infections and demonstrate the feasibility of panel-based PCR-based diagnostics for these sometimes-complex infections. The BF-JIP, designed for testing synovial fluid, could be modified to provide a useful diagnostic for testing pleural fluid.