Antimicrobial activity of bitespiramycin, a new genetically engineered macrolide

Carrimycin, as One of the Drugs in Combination Therapy, for the Treatment of Carbapenem-Resistant Acinetobacter Baumannii Infection

Purpose

Infection with carbapenem-resistant Acinetobacter baumannii (CRAB) is a tough nut to crack. Carrimycin is a novel recombinant macrolide antibiotic, and has good anti-infection effects in vivo. At present, it is rarely reported for treatment of CRAB infection. We present a case where a patient with COVID-19 complicated by CRAB infection was successfully treated with a combination therapy including carrimycin, offering clinical insights and experience.

Patients and Methods

The patient infected with CRAB was cured by carrimycin combined with tigecycline and amikacin ultimately. We analyzed and summarized the therapeutic regimen and disease feature to provide reference for clinical treatment.

Results

The patient was admitted to emergency observation wards with fever and was diagnosed with COVID-19 pneumonia. During the treatment, his condition worsened. He had a fever, cough, and expectoration. After 3 days of empirical treatment with meropenem, tested positive for A. baumannii infection by the next-generation sequencing, and CRAB was detected in blood and sputum culture. Then, he was administered with tigecycline and amikacin immediately for 5 days, however the therapeutic effect was not significant. The patient still remained in a high inflammatory response. Ultimately, the treatment regimen was changed to carrimycin combined with tigecycline and amikacin for 7 days, and then carrimycin combined with tigecycline for 10 days, the patient's clinical condition gradually improved. The patient received carrimycin monotherapy for 7 days, then discharged.

Conclusion

Carrimycin may be a bright alternative for CRAB infection as one of the drugs in combination therapy, especially in a patient with hyperinflammatory response.

Therapeutic applications of carbohydrate-based compounds: a sweet solution for medical advancement

Carbohydrates, one of the most abundant biomolecules found in nature, have been seen traditionally as a dietary component of foods. Recent findings, however, have unveiled their medicinal potential in the form of carbohydrates-derived drugs. Their remarkable structural diversity, high optical purity, bioavailability, low toxicity and the presence of multiple functional groups have positioned them as a valuable scaffold and an exciting frontier in contemporary therapeutics. At present, more than 170 carbohydrates-based therapeutics have been granted approval by varying regulatory agencies such as United States Food and Drug Administration (FDA), Japan Pharmaceuticals and Medical Devices Agency (PMDA), Chinese National Medical Products Administration (NMPA), and the European Medicines Agency (EMA). This article explores an overview of the fascinating potential and impact of carbohydrate-derived compounds as pharmacological agents and drug delivery vehicles.

Carrimycin ameliorates lipopolysaccharide and cecal ligation and puncture-induced sepsis in mice

Carrimycin (CA), sanctioned by China's National Medical Products Administration (NMPA) in 2019 for treating acute bronchitis and sinusitis, has recently been observed to exhibit multifaceted biological activities, encompassing anti-inflammatory, antiviral, and anti-tumor properties. Despite these applications, its efficacy in sepsis treatment remains unexplored. This study introduces a novel function of CA, demonstrating its capacity to mitigate sepsis induced by lipopolysaccharide (LPS) and cecal ligation and puncture (CLP) in mice models. Our research employed in vitro assays, real-time quantitative polymerase chain reaction (RT-qPCR), and RNA-seq analysis to establish that CA significantly reduces the levels of pro-inflammatory cytokines, namely tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6), in response to LPS stimulation. Additionally, Western blotting and immunofluorescence assays revealed that CA impedes Nuclear Factor Kappa B (NF-κB) activation in LPS-stimulated RAW264.7 cells. Complementing these findings, in vivo experiments demonstrated that CA effectively alleviates LPS- and CLP-triggered organ inflammation in C57BL/6 mice. Further insights were gained through 16S sequencing, highlighting CA's pivotal role in enhancing gut microbiota diversity and modulating metabolic pathways, particularly by augmenting the production of short-chain fatty acids in mice subjected to CLP. Notably, a comparative analysis revealed that CA's anti-inflammatory efficacy surpasses that of equivalent doses of aspirin (ASP) and TIENAM. Collectively, these findings suggest that CA exhibits significant therapeutic potential in sepsis treatment. This discovery provides a foundational theoretical basis for the clinical application of CA in sepsis management.

Effects of carrimycin on biomarkers of inflammation and immune function in tumor patients with sepsis: A multicenter double-blind randomized controlled trial

Carrimycin is a potential immune-regulating agent for sepsis in patients with tumors. In this study, we investigated its effects on inflammation and immune function in tumor patients with sepsis. In total, 120 participants were randomized to receive either carrimycin treatment (400 mg/day) (n = 62) or placebo (n = 58) for 7 days. The primary outcomes were immune-related indicators. Subsequently, patients were stratified into two subgroups (CD4 < 38.25% and CD8 < 25.195%). Ninety-nine participants were analyzed: 47 and 52 in the carrimycin and placebo groups, respectively. HLA-DR levels were rapidly increased in the carrimycin group; however, the placebo group initially experienced a decline in HLA-DR level at 1 day after administration. In the subgroup with CD4 < 38.25%, the carrimycin group exhibited significantly higher HLA-DR levels than the placebo group (2.270, P = 0.023) 1 day after administration and the degree of increase in HLA-DR in the carrimycin group was higher than that in the placebo group (2.057, P = 0.040). In the CD8 < 25.195% subgroup, the carrimycin group demonstrated significantly higher levels of CD8+ T cells than the placebo group at 3 (2.300,P = 0.027) and 5 (2.106, P = 0.035) days after administration. Carrimycin intervention led to significant reductions in the SOFA, APACHE II, PCT, and CRP levels. No adverse events were observed. In tumor patients with sepsis, particularly in those experiencing immunological suppression, carrimycin effectively regulates immune responses by increasing HLA-DR and CD8+ T cell levels and plays an anti-infective role, reducing disease severity. (Chictr.org.cn, ID Number: ChiCTR2000032339).

A Case of Multidrug-Resistant Klebsiella pneumoniae Treated with Carrimycin

One of the most pressing emerging issues in bacterial resistance is multidrug-resistant Klebsiella pneumoniae. The treatment of K. pneumoniae infections is often problematic because of the lack of available therapeutic options, leading to negative effects on morbidity, mortality, and healthcare-associated costs. Carrimycin is a macrolide antibiotic with good antibacterial effects. In this study, we report a patient diagnosed with multidrug-resistant K. pneumoniae infection who was treated with carrimycin. The patient presented with cough, expectoration, dyspnea, and severe hypoxemia requiring noninvasive ventilation. We successively used a variety of antibiotics, including meropenem, tigecycline, and polymyxin, with unsatisfactory results. Finally, we used carrimycin, and the patient's condition improved, resulting in hospital discharge. Therefore, for patients with multidrug-resistant K. pneumoniae infection that does not respond to conventional anti-infective treatments, carrimycin can be considered a treatment option.

Carbohydrate-based drugs launched during 2000-2021

Carbohydrates are fundamental molecules involved in nearly all aspects of lives, such as being involved in formating the genetic and energy materials, supporting the structure of organisms, constituting invasion and host defense systems, and forming antibiotics secondary metabolites. The naturally occurring carbohydrates and their derivatives have been extensively studied as therapeutic agents for the treatment of various diseases. During 2000 to 2021, totally 54 carbohydrate-based drugs which contain carbohydrate moities as the major structural units have been approved as drugs or diagnostic agents. Here we provide a comprehensive review on the chemical structures, activities, and clinical trial results of these carbohydrate-based drugs, which are categorized by their indications into antiviral drugs, antibacterial/antiparasitic drugs, anticancer drugs, antidiabetics drugs, cardiovascular drugs, nervous system drugs, and other agents.

Midecamycin Is Inactivated by Several Different Sugar Moieties at Its Inactivation Site

Glycosylation inactivation is one of the important macrolide resistance mechanisms. The accumulated evidences attributed glycosylation inactivation to a glucosylation modification at the inactivation sites of macrolides. Whether other glycosylation modifications lead to macrolides inactivation is unclear. Herein, we demonstrated that varied glycosylation modifications could cause inactivation of midecamycin, a 16-membered macrolide antibiotic used clinically and agriculturally. Specifically, an actinomycetic glycosyltransferase (GT) OleD was selected for its glycodiversification capacity towards midecamycin. OleD was demonstrated to recognize UDP-D-glucose, UDP-D-xylose, UDP-galactose, UDP-rhamnose and UDP-N-acetylglucosamine to yield corresponding midecamycin 2'-O-glycosides, most of which displayed low yields. Protein engineering of OleD was thus performed to improve its conversions towards sugar donors. Q327F was the most favorable variant with seven times the conversion enhancement towards UDP-N-acetylglucosamine. Likewise, Q327A exhibited 30% conversion enhancement towards UDP-D-xylose. Potent biocatalysts for midecamycin glycosylation were thus obtained through protein engineering. Wild OleD, Q327F and Q327A were used as biocatalysts for scale-up preparation of midecamycin 2'-O-glucopyranoside, midecamycin 2'-O-GlcNAc and midecamycin 2'-O-xylopyranoside. In contrast to midecamycin, these midecamycin 2'-O-glycosides displayed no antimicrobial activities. These evidences suggested that besides glucosylation, other glycosylation patterns also could inactivate midecamycin, providing a new inactivation mechanism for midecamycin resistance. Cumulatively, glycosylation inactivation of midecamycin was independent of the type of attached sugar moieties at its inactivation site.