Ringing bells: Morganella morganii fights for recognition.

OBJECTIVES: The global increase in rare opportunistic microbial infections is alarming. The current review was undertaken to study the diversified disease spectrum, pathogenicity, and resistance patterns of Morganella morganii. STUDY DESIGN: This study is a review of the diversified disease spectrum of M. morganii. METHODS: The articles used in this review were all extracted from PubMed and Google Scholar, using the terms 'M. morganii', 'prevalence', 'virulence factors', 'infections', 'resistance pattern', and 'genomics'. This review includes original articles, reviews, and case reports focusing on M. morganii, hospital-based prevalence studies, and studies on resistance in M. morganii published between 1906 and April 2019. Articles published in English, French, Spanish, and Chinese were reviewed. RESULTS: M. morganii has had a significant impact as a clinical pathogen and the pace of its occurrence and the increase in its resistance rates puts this bacterium on the path to becoming the next 'superbug'. These developments not only impact M. morganii, but as a result of gene and plasmid transfer evolution, other clinical pathogens have been able to acquire their diverse intrinsic and acquired virulence genes. Its vast host range raises concerns around its capacity to generate new infections through novel symbiotic relationships. CONCLUSIONS: M. morganii opportunism is being increasingly reported across the globe. This bacterium is accumulating intrinsic and acquired multidrug resistance genes, resulting in increased morbidity and mortality rates for M. morganii infections and complicating its treatment. M. morganii should be recognized as a clinically significant pathogen, and clinicians should place this microorganism in the list of causative possibilities during patient care. It is important for both the infection control activities in hospitals and in public health sector.