Antimicrobial-resistant (AMR) bacterial infections, including those caused by Elizabethkingia anophelis (EA), have emerged as a clinical crisis worldwide. With the increased reports of outbreak and its extensive-antibiotic resistant isolates, the treatment of diseases is challenging. Outer membrane vesicles (OMVs) are purposely secreted by Gram-negative bacteria and contain materials derived from their parent bacterium. OMVs specialize and tailor their functions by carrying different components to challenging environments and communicate with other microorganisms or hosts.

In this study, we sought to understand the characteristics of EA OMVs under different antibiotics stress. The two clinical isolated strains against seven commonly used antibiotics (Amikacin, Ampicillin, Polymyxin B, Colistin, Chloramphenicol, Minocycline, Meropenem and Imipenem) were analyzed. The growth culture medium was centrifuged and filtered. OMVs were recovered by ultracentrifugation and quantified the protein concentration, particle size, and concentration per CFU of OMVs. Disk diffusion assay was evaluated whether OMVs packaged anti-antibiotic substances.

The results indicated that Imipenem and Chloramphenicol would lead to more OMVs production with about 110-145 nm particle size. Its OMVs seem not contain the anti-antibiotic substance compared to bacteria lysate. This study offers important insights for understanding the characteristics of EA OMVs and worth to further investigation

Carbapenem resistant Acinetobacter baumannii (CRAb) is an important global pathogen contributing to increased morbidity and mortality in hospitalized patients, due to limited alternative treatment options. Nine international clonal (IC) lineages have been identified in many countries worldwide, however data still lacks from some parts of the world, particularly in Africa. We hereby present the molecular epidemiology of MDR A. baumannii from four hospitals in Khartoum, Sudan, collected from 2017-2018. Forty-two isolates were whole-genome sequenced, and subsequent molecular epidemiology was determined by core genome MLST (cgMLST), and their resistomes identified. All isolates had an array of diverse antibiotic resistance mechanisms conferring resistance to multiple classes of antibiotics. We found a predominance (88%) of IC2 (with the intrinsic OXA-66 and acquired OXA-23), and some with NDM-1. IC2 isolates were sub-divided into 4 STs separated by 5 to 431 allelic differences, and with evidence of seven transmission clusters. Isolates belonging to IC1, IC5 and IC9 were also identified. These data illustrate that MDR IC2 A. baumannii are widely distributed in Khartoum hospitals and are in possession of multiple antibiotic resistance determinants.