AUTHOR=Jabeen Ishrat , Islam Sohidul , Hassan A. K. M. Imrul , Tasnim Zerin , Shuvo Sabbir R. 

TITLE=A brief insight into Citrobacter species - a growing threat to public health

JOURNAL=Frontiers in Antibiotics

VOLUME=2

YEAR=2023

URL=https://www.frontiersin.org/journals/antibiotics/articles/10.3389/frabi.2023.1276982

DOI=10.3389/frabi.2023.1276982

ISSN=2813-2467

ABSTRACT=<p><italic>Citrobacter</italic> spp. are Gram-negative, non-spore forming, rod-shaped, facultative anaerobic bacteria from the <italic>Enterobacteriaceae</italic> family often found in soil, sewage, sludge, water, food, and the intestinal tracts of animals and humans. Several members of <italic>Citrobacter</italic> spp. especially <italic>C. freundii</italic>, <italic>C. koseri</italic>, <italic>C. braakii</italic> are frequently detected in newborn illnesses, urinary tract infections, and patients with severe underlying conditions, including hypertension, diabetes, cancer, and respiratory infections, or those who are immunocompromised. Strains of <italic>Citrobacter</italic> spp. can spread vertically or horizontally from carriers or other hospital sources and thus cause nosocomial infections in hospital settings. A total of 19 <italic>Citrobacter</italic> genomospecies have been recognized based on genomics. It has been noted that the <italic>Citrobacter</italic> genus acquired antimicrobial resistance and virulence, including invasion, colonization, biofilm formation, and toxin production. The recent emergence and spread of antimicrobial resistance to β-lactams, carbapenems, fluoroquinolones, aminoglycosides, and colistin in <italic>Citrobacter</italic> spp. through chromosomal and plasmid-mediated resistance limits the empiric treatment options. Therefore, combination therapy involving costly and potentially hazardous antibiotics poses significant challenges in treating <italic>Citrobacter</italic> infections. Here we summarized the nomenclature of <italic>Citrobacter</italic> spp., clinical manifestations, epidemiology, pathogenesis, antibiotic resistance mechanisms, and treatments from various clinical samples. This review will expand our knowledge of the genomics and epidemiology of <italic>Citrobacter</italic> spp., enabling improved control of infections and the spread of these organisms.</p>