Antimicrobial Resistance of Aeromonas Species Isolated from Cultured Indian Major Carp, Labeo rohita: Possible Public Health Concern

In India, Labeo rohita is widely cultured and consumed freshwater fish. Aeromonads are etiological agents of major bacterial fish diseases like furunculosis, haemorrhagic septicaemia, skin ulcers, fin/tail rot and dropsy, causing significant economic losses in carp culture. Aeromonas species are widely distributed in aquatic environment which is considered as important vehicle of Aeromonas infections to fish and humans. Some of the Aeromonas spp. causes gastroenteritis, septicaemia, peritonitis, meningitis and eye infections in humans. In the present study Aeromonas species were isolated from diseased freshwater fish Labeo rohita collected from two districts viz., West Godavari and SPSR Nellore of Andhra Pradesh, India. A Total of 12 Aeromonas spp. were isolated and identified by biochemical tests. A. veronii bv. veronii (35%) was dominant when compared to other Aeromonas spp. Further, Antimicrobial resistance and multiple Antimicrobial resistance (MAR) of all Aeromonas spp. were tested against 17 antibiotics being frequently used for human diseases. The Antimicrobial resistance of all the 12 Aeromonas spp. have shown significantly high (p<0.05) resistance (100%) to ampicillin, amoxyclave and oxytetracycline except A. cavernicola when compared to other antibiotics. The MAR index of Aeromonas spp. ranged from 0.18-0.76, which indicates origination of isolated Aeromonas spp. from high risk sources of contamination. A. hydrophila, A. veronii bv. sobria, A. veronii bv. veronii, A. schubertii and A. jandaei isolated in this study were found to be pathogenic to humans also. The results revealed the pathogenic potential of Aeromonas infections in freshwater fish culture and emerging threats to public health.

Characterization and Antimicrobial Resistance of Environmental and Clinical Aeromonas Species Isolated from Fresh Water Ornamental Fish and Associated Farming Environment in Sri Lanka

The aims of this study were to characterize and investigate antimicrobial susceptibility and presence of integrons in 161 Aeromonas spp. isolated from ornamental freshwater fish farming environment, apparently healthy and diseased fish. Phylogenetic analyses of the gyrB gene sequences identified Aeromonas veronii as the most abundant species (75.8%) followed by Aeromonas hydrophila (9.3%), Aeromonas caviae (5%), Aeromonas jandaei (4.3%), Aeromonas dhakensis (3.7%), Aeromonas sobria (0.6%), Aeromonas media (0.6%), and Aeromonas popoffii (0.6%). Susceptibility to thirteen antimicrobials was determined and antimicrobial resistance frequencies were: amoxicillin (92.5%), enrofloxacin (67.1%), nalidixic acid (63.4%), erythromycin (26.1%), tetracycline (23.6%), imipenem (18%), trimethoprim-sulfamethoxazole (16.8%), and gentamicin (16.8%). Multi-drug resistance (MDR) was widespread among the isolates (51.6%, 83/161) with 51.6% (63/122) A. veronii isolates being MDR. In addition, 68.3% of isolates had multiple antibiotic resistance (MAR) indexes higher than 0.2, suggesting that they originated from a high-risk source of contamination where antimicrobials are often used. In all, 21.7% isolates carried class 1 integrons, with 97.1% having gene cassettes, while there were 12 isolates carrying class 2 integron gene cassettes. Our findings highlight that the aquatic environment and ornamental fish act as reservoirs of multidrug resistant Aeromonas spp. and underline the need for a judicious use of antimicrobials and timely surveillance of antimicrobial resistance (AMR) in aquaculture.

The Nasal Epithelium as a Route of Infection and Clinical Signs Changes, in Rainbow Trout (Oncorhynchus mykiss) Fingerlings Infected with Aeromonas spp

The genus Aeromonas is a group of bacteria that is widely distributed in water bodies and belongs to the normal intestinal microbiota of aquatic and terrestrial animals. In the present work, rainbow trout fingerlings were experimentally infected by an immersion bath with different Aeromonas species. Subsequently, the behavior of the infected groups was observed and recorded. Infected fingerlings were evaluated by histopathology. The highest percentages of hyperpigmentation (18.88%) and inappetence (47.7%) were observed in fish infected with A. salmonicida, while abnormal swimming (83.33%) was recorded in fish infected with A. bestiarum. In histopathological findings, the highest percentages were observed in the olfactory epithelium (50.0%) for A. lusitana and A. salmonicida (41.1%)-infected fish. While, in the nervous system, the cerebral hemispheres (31.1%) in A. media-infected fish and the oblongata medulla (40.0%) in the A. bestiarum-infected fish presented the highest percentages. Meanwhile, A. salmonicida and A. bestiarum have the highest pathogenicity and virulence based on the histopathological findings in the olfactory epithelium and nervous system. Due to the proximity of the olfactory epithelium with the nervous tissue, it is possible that the infection generated by the Aeromonas species and the histopathological findings in the nervous tissue are reflected in different behavioral changes that suggest differences in the pathogenicity and virulence of the bacteria.

Multi-drug resistant Aeromonas species in Annelida: An evidence of pathogen harbouring leech in recreation water nexus of Oghara Nigeria environs

Aeromonas infections have shown diverse complications in management due to the multiple antibiotic resistance observed amongst its members. The origin and habitat of its resistance development yet remain vague. The present study depicts Leech and its infested recreational water as a reservoir of multidrug-resistant Aeromonas hydrophila. Skin swabs of recreational water bathers before (Bb)/after bathing (Ab) (250 each) and 250 leeches (Hirudomedicinalis) were collected from recreational water sites. Standard Microbiological and Molecular biology methods were applied for isolation and characterization. Two hundred and forty-five (98%)Bb specimen, showed a negative growth oforganisms, 84% (210) of the Ab specimen harboured presumptive Aeromonas species, while 100% (250) Leeches specimen harboured Aeromonas species. The Polymerase Chain Reaction (PCR) of 16SrRNA gene detection confirmed all (465/100%) isolates as Aeromonas species while 13.6% (63) were further delineated as Aeromonas hydrophila. The antibiogram showed 45(97.82%) resistance to the β-lactam antibiotic and other antibiotic groups. The PCR detection of resistant markers, virulent and plasmid profile of isolates reveals conjugative plasmid mediation, lip (123/97.6%), act (104/82%), hhly (93/73%) genes and BlaampC gene, BlaTEM, gene and BlaSHV gene. Observation of pathogens with similar multiple antibiotic-resistant gene-profile both in the bathers'skin swab and gut of leeches indicates origin/habitat, association and suggests the gut of leeches as breeding habitat for the pathogen. This is an emerging public health concern that associates specifically the environment and human superficial infections.

Climatic Alterations Influence Bacterial Growth, Biofilm Production and Antimicrobial Resistance Profiles in Aeromonas spp.

Climate change is expected to create environmental disruptions that will impact a wide array of biota. Projections for freshwater ecosystems include severe alterations with gradients across geographical areas. Life traits in bacteria are modulated by environmental parameters, but there is still uncertainty regarding bacterial responses to changes caused by climatic alterations. In this study, we used a river water microcosm model to evaluate how Aeromonas spp., an important pathogenic and zoonotic genus ubiquitary in aquatic ecosystems, responds to environmental variations of temperature and pH as expected by future projections. Namely, we evaluated bacterial growth, biofilm production and antimicrobial resistance profiles of Aeromonas species in pure and mixed cultures. Biofilm production was significantly influenced by temperature and culture, while temperature and pH affected bacterial growth. Reversion of antimicrobial susceptibility status occurred in the majority of strains and tested antimicrobial compounds, with several combinations of temperature and pH contributing to this effect. Current results highlight the consequences that bacterial genus such as Aeromonas will experience with climatic alterations, specifically how their proliferation and virulence and phenotypic resistance expression will be modulated. Such information is fundamental to predict and prevent future outbreaks and deleterious effects that these bacterial species might have in human and animal populations.

Aeromonas species obtained from different farmed aquatic species in India and Taiwan show high phenotypic relatedness despite species diversity

Objectives Aeromonads cause severe diseases in farmed aquatic organisms. Herein, we examined 28 isolates causing disease in farmed aquatic organisms from India (n = 24) and Taiwan (n = 4) to gain insight of their genotypic and phenotypic properties. Results API 20NE biochemical phenotyping showed ≥ 90% similarity classifying all isolates as Aeromonas hydrophila. 16S rRNA genotyping showed ≥ 98% homology among all isolates with A. sobria (NR119044.1ATCC), A. veronii (MK990549.1), A. caviae (NR029252.1) and A. hydrophila (MG984625.1ATCC) and other reference strains. In contrast, gyrB showed a higher intraspecies diversity (≥ 96%) than 16S rRNA delineating the 28 isolates into three groups. Group-I consisted of seven Indian isolates clustered with A. sobria (MK484163.1ATCC), group-II comprised of five Indian and two Taiwanese isolates clustered with A. veronii AF417626.1ATCC while group-III had 11 Indian and three Taiwanese isolates grouped with A. hydrophila (AY987520.1 and DQ519366.1) reference strains. None of our isolates clustered with A. caviae (AJ868400.1ATCC) reference strain. These findings suggest that A. sobria, A. veronii and A. hydrophila could be the etiological agents of diseases observed in farmed fish and soft-shelled turtles (Pelodiscus sinensis) examined in this study. Overall, our findings accentuate the importance of combining phenotyping with genotyping for correct taxonomic classification of Aeromonas spp. in Aquaculture.

Rethinking antimicrobial prophylaxis in patients receiving medicinal leech therapy

Disclaimer In an effort to expedite the publication of articles , AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Purpose To describe challenges in the management of prophylaxis against infections for patients receiving medicinal leech therapy given changes in antimicrobial resistance patterns in the normal flora of leeches. Summary This article presents a patient case of reconstructive surgery complicated by infection associated with the use of medicinal leeches, as well as a discussion of prophylaxis in medicinal leech therapy, focusing on considerations for choosing a prophylactic agent. Conclusion Our case report highlights resistance changes in Aeromonas isolates associated with medicinal leeches and the potential for complications if isolates resistant to chosen prophylactic agents arise. When administering antimicrobial prophylaxis in patients receiving medicinal leech therapy, clinicians should be familiar with the susceptibilities of Aeromonas species but also conscious of evolving antimicrobial resistance given the extent of the consequences of infected surgical grafts.