Contemporary threats of bacterial infections in freshwater fish

Abstract

Changes occurring in freshwater ecosystems seem to be fundamental in the development of all microorganisms, including those pathogenic to fish. This has been especially evident in recent years during which dynamic variations in bacterial fish pathology have been observed. Gram-negative bacteria commonly known to be pathogenic to fish, like Aeromonas spp., Flavobacterium spp., Pseudomonas spp., and Shewanella putrefaciens are replaced by other species, which until now have not been known to be virulent or even conditionally pathogenic to fish. Nowadays, among these other species Acinetobacter spp., Plesiomonas shigelloides, Sphingomonas paucimobilis, and Stenotrophomonas maltophilia are the most frequently isolated from fish exhibiting clinical signs of disease. Two Gram-positive bacteria have become pathogens of particular importance in fish pathology in Poland: Lactococcus garviae and Streptococcus iniae. In addition, infections caused by the Gram-positive bacterium Kocuria rhizophila have appeared in recent years. This bacterium has not been known until now to be pathogenic to fish. Therefore, this infection could be called an emergent disease.

Complex phyllosphere microbiome aids in the establishment of the invasive macrophyteHydrilla verticillata(L.) under conditions of nitrogen scarcity

“…Several bacterial genera that have been implicated as disease causing agents in humans [48], livestock [49], or fish [50] were found in the dataset, some of them at high relative abundances (Table S1). These include Legionella (Legionnaires’ disease, Pontiac fever), Aeromonas (gastroenteritis and wound infections), Mycobacterium aubagnense (pulmonary infections, necrosis), Enterococcus faecalis (urinary tract infections), Escherichia coli (gastroenteritis, urinary tract infections), Pseudomonas (nosocomial infections), Tsukamurella pulmonis (bacteraemia, pulmonary infections), Acinetobacter (bacteraemia, pulmonary infections, meningitis), Stenotrophomonas (emerging multidrug-resistant global opportunistic pathogen), Flavobacterium (fish pathogen), Streptococcus parauberis (livestock and fish pathogen), or Kocuria ( fish pathogen ).…”

Bacterial Diversity and Antibiotic Susceptibility of Sparus aurata from Aquaculture

“…Of the species found in this study, only Pseudomonas spp. and K. rhizophila appeared to frequently cause diseases in fish, K. rhizophila being an emerging pathogen [ 41 , 42 ]. Pseudomonas spp.…”

“…are ubiquitous in nature, and P. fluorescens is the most important species in fish infections (not found in this study), although P. putida had already been found in internal organs of fish and P. stutzeri in sediments of marine waters [ 43 ]. This genus is responsible for strawberry disease and septicaemia in some fish species [ 42 ]. P. putida and P. stutzeri are also opportunistic pathogens in humans and were already associated with bacteraemia, endocarditis, keratitis, meningitis, pneumonia, skin and soft tissue infections and urinary tract infections [ 44 , 45 , 46 , 47 , 48 ].…”

“…are Gram-positive and coccoid bacteria isolated from numerous environments: skin of mammals, marine sediments, soil and food [ 49 , 50 , 51 , 52 , 53 ]. Specifically, K. rhizophila causes a variety of lesions in fish and is responsible for a 50% mortality rate: exophthalmia, skin petechiae, increased skin melanization, liver congestion, inflammation of the intestine and hemorrhages [ 42 ]. Reports revealed that this species was already responsible for some infections in humans, mainly catheter-related bacteremia [ 54 ].…”

Structural and Serological Studies of the O6-Related Antigen of Aeromonas veronii bv. sobria Strain K557 Isolated from Cyprinus carpio on a Polish Fish Farm, which Contains l-perosamine (4-amino-4,6-dideoxy-l-mannose), a Unique Sugar Characteristic for Aeromonas Serogroup O6

“…are the most common among bacterial fish diseases. As demonstrated recently by data collected during the last several years in Poland by Pękala-Safińska, health disorders caused by Aeromonas species were mostly observed in carp ( Cyprinus carpio L.) and were usually manifested by skin lesions (MAI) in the form of ulceration as well as fish mortalities [48].…”