Antibiotic resistance is on the WHO’s top 10 list of global public health threats due to its rapid emergence and spread but also because of the high morbidity and mortality associated with it. Amongst the main species driving this phenomenon is A. baumannii, a member of the ESKAPE group of medical assistance-associated infections causing species famous for its extensively drug-resistant phenotypes. Our findings note a 91.52% frequency of extensively drug-resistant carbapenem-resistant A. baumannii (XDR CRAB) phenotype amongst clinical isolates from multiple hospitals in two major cities from northwestern and central Romania, harboring multiple antibiotic resistance genes such as bla_OXA-23-like in 108 (91.5%) isolates, bla_{OXA-24/40-like} in 88 (74.6%) isolates, bla_NDM in 29 (25%) isolates, ArmA in 75 (63.6%) isolates, and ant(3″)-I in 69 (58.5%) isolates and sul1 in 113 (95.76%) isolates. The isolates, although nearly identical in phenotype, displayed different genotypical profiles, with varying degrees of similarity across hospitals and cities, raising the possibility of both local outbreaks of a single clone and widespread dissemination of resistant isolates.

Yokenella regensburgei is a Gram-negative rod part of the Enterobacteriaceae family (order Enterobacterales) and a rare cause of human infections. Although improved diagnostic methods have led to an increase in reports of this elusive pathogen, information remains limited. In order to provide a better understanding of this bacterium, we developed the first comprehensive review of its biology, biochemical profile, antimicrobial resistance pattern, virulence factors, natural reservoir and involvement in various veterinary and human infections. Human infections with this bacterium are scarcely reported, most probably due to constraints regarding its identification and biochemical similarities to Hafnia alvei. Multiple systematic searches revealed 23 cases of human infection, with a seemingly worldwide distribution, mostly in middle-aged or elderly male patients, often associated with immunosuppression. To date, Y. regensburgei has been reported in skin and soft tissue infections, bacteremia and sepsis, osteoarticular infections and in others such as urinary tract and digestive infections. The unique ability of Y. regensburgei to degrade polystyrene presents a novel and promising avenue for addressing plastic pollution in the near future. However, large-scale applications of this bacterium will undoubtedly increase human exposure, highlighting the necessity for comprehensive research into its role in human and veterinary infections, pathogenicity and antibiotic resistance.

Weeksella virosa (W. virosa) is a rare, non-saccharolytic Gram-negative bacterium initially described in the 1970s, later proposed as a distinct genus in 1986. The genus Weeksella currently contains two species, namely W. virosa and W. massiliensis. Although primarily considered non-pathogenic, recent evidence has linked W. virosa to a limited number of clinical infections, mostly in immunocompromised patients. This review aims to consolidate the current body of knowledge on W. virosa, encompassing its microbiological and biochemical characteristics, involvement in human and animal infections, antimicrobial susceptibility profiles, and a critical evaluation of existing diagnostic methodologies. This review includes 13 case reports detailing 16 human cases retrieved from multiple databases, highlighting diagnostic inconsistencies and a lack of standardized antimicrobial susceptibility testing. Although W. virosa is generally susceptible to most antibiotics with the exception of aminoglycosides, recent reports seem to suggest a possible emerging resistance trend. The presence of this organism in hospital environments raises concerns about its potential transmission within healthcare settings. While biochemical testing appears to offer reasonably accurate identification of W. virosa, molecular confirmation may be warranted in some cases mainly due to the organism’s rarity. The reliability of MALDI-TOF MS for the identification of W. virosa remains currently uncertain. Further studies, including electron microscopy and genome-wide analysis, are urgently needed to clarify the pathogenic potential of this bacterium and guide clinical management. This review underscores the necessity for awareness among clinicians and microbiologists regarding this underrecognized pathogen.