Antimicrobial resistance in Morganella morganii isolates from aquatic environments: a systematic review

Abstract

Morganella morganii has been recognized as an opportunistic bacterium involved in healthcare-associated infections worldwide. In addition to living as a symbiote in the intestines of humans and animals, M. morgannii is also known to colonize different sources of water. However, knowledge about the dynamics of susceptibility to antimicrobials in environmental isolates of this species is scarce. Thus, this study aimed to investigate antimicrobial resistance in M. morganii isolated from aquatic environments. A systematic review of the literature was conducted according to the Cochrane Handbook and the search and analysis of the articles followed the guidelines of the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA). A total of 121 environmental isolates of M. morganii were evaluated from the eight selected studies. M. morganii was mostly recovered in spring water (73/121; 60%), followed by wastewater (sewage) (38/121; 31%), lake (4/121; 4%), sea/beach (4 /121; 4%) and river (1/121; 1%). Of the isolates included, 31% (38/121) were resistant to at least one of the tested antimicrobials. Resistance to beta-lactam, aminoglycosides, chloramphenicol, quinolones, rifampicin, and tetracycline have been reported, as well as the presence of quinolone resistance determinants (qnrS; target protection), aminoglycosides (aac(6’)-Ib; drug modification), and tetracyclines (tetD; target protection). In conclusion, the presence of M. morganii in the aquatic environment must be monitored to avoid the dissemination and exchange of resistance genes by this Gram-negative bacillus, strategies that can mitigate the ineffectiveness of currently available therapeutic options.