Bacteriological, Clinical and Virulence Aspects of Aeromonas-associated Diseases in Humans

Abstract

Aeromonads have been isolated from varied environmental sources such as polluted and drinking water, as well as from tissues and body fluids of cold and warm-blooded animals. A phenotypically and genotypically heterogenous bacteria, aeromonads can be successfully identified by ribotyping and/or by analysing gyrB gene sequence, apart from classical biochemical characterization. Aeromonads are known to cause scepticemia in aquatic organisms, gastroenteritis and extraintestinal diseases such as scepticemia, skin, eye, wound and respiratory tract infections in humans. Several virulence and antibiotic resistance genes have been identified and isolated from this group, which if present in their mobile genetic elements, may be horizontally transferred to other naive environmental bacteria posing threat to the society. The extensive and indiscriminate use of antibiotics has given rise to many resistant varieties of bacteria. Multidrug resistance genes, such as NDM1, have been identified in this group of bacteria which is of serious health concern. Therefore, it is important to understand how antibiotic resistance develops and spreads in order to undertake preventive measures. It is also necessary to search and map putative virulence genes of Aeromonas for fighting the diseases caused by them. This review encompasses current knowledge of bacteriological, environmental, clinical and virulence aspects of the Aeromonas group and related diseases in humans and other animals of human concern.

Virulence-Associated Genes and Antimicrobial Resistance of Aeromonas hydrophila Isolates from Animal, Food, and Human Sources in Brazil

“…Given the risk to human health, the incidence of antimicrobial resistance is alarming, particularly among A. hydrophila, A. caviae, and A. sobria, which are considered pathogens responsible for infections in both fish and humans [37]. These bacteria may be resistant by carrying intrinsic genes or by acquiring resistance markers from other microorganisms [4,8]. Studies demonstrate that Aeromonas spp.…”

“…Arctocephalus gazella 1 4 S E Ardea cocoi 2 1 S E Chelonia mydas 3 1 S E Eretmochelys imbricata 4 1 S E Eubalaena australis 5 5 S E Leucophaeus atricilla 6 5 S E Lontra longicaudis 7 1 S E Megaptera novaeangliae 8 10 SE Pontoporia blainvillei 9 3 ST (1), SE (2) Stenella coeruleoalba 10 7 S T Sterna hirundinacea 11 2 S E Sula leucogaster 12 2 S E Trichechus manatus 13 10 SE * Brazilian geographic areas: MW: midwest; NE: northeast; ST: south; SE-southeast. A The popular names.…”

“…Recognized as emerging pathogens, their situation is privileged when natural disasters occur, having been largely isolated from skin and soft tissue infections in tsunami survivors that struck Thailand in 2004 [6]. Besides, Aeromonas have been recognized as a relevant etiological agent in human gastrointestinal infections, having been isolated from food and drinking water samples [7,8].…”

Patients with Monomicrobial Aeromonas Necrotizing Fasciitis Had Higher Mortality Rates Than Those of Vibrio vulnificus Infections

“…VVP and VvsA are siginificantly produced in the interstitial tissues of limbs, and cause serious collagenolytic, hemorrhagic or edematous skin damage in the extremities through digestion of the vascular basement membrane and vasodilatation (24,25). Aeromonas hydrophila and Aeromonas sobria can produce hemolysin, cytolytic enterotoxin, endotoxin, protease, lipases, and four types of secretory systems (types II, III, IV and VI), which are associated with extensive muscular necrosis, gastrointestinal tract infection and septicemia (12,22,23,25,26). In particular, those virulance factors of Vibrio vulnificus and Aeromonas species were commonly reported to impair the phagocytic activity of the reticuloendothelial system, and to result in bacterial translocation and bacteremia in patients with hepatic decompensation (22)(23)(24)(25)(26)(27)(28).…”

Role of Bacterial Secretion Systems and Effector Proteins – Insight into the Pathogenicity Mechanisms in Aeromonas

“…The type VI secretion system acts by inserting toxins into the host via valine-glycine repeat proteins and hemolysin-coregulated proteins (Wang et al, 2011;Yang et al, 2018;Fernandez-Bravo et al, 2019). After secretion, these proteins exhibit antimicrobial pore-forming properties or remain as structural proteins (Bhowmick & Bhattacharjee, 2018). In recent years, research is particularly focused on the role of expression of genes encoding various toxins and secretion pathways in promoting Aeromonas virulence mechanisms (Dacanay et al, 2006;Vanden Bergh & Frey, 2014;Soto-Davila et al, 2019).…”