scholarly journals Investigation of the Prevalence, Virulence Genes, and Antibiogram of Motile Aeromonads Isolated from Nile Tilapia Fish Farms in Egypt and Assessment of their Water Quality

Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1432
Author(s):  
Fatma A. El-Gohary ◽  
Eman Zahran ◽  
Eman A. Abd El-Gawad ◽  
Adel H. El-Gohary ◽  
Fatma M. Abdelhamid ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Samples ◽  
Nile Tilapia ◽  
Bacterial Infections ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Fish Farms ◽  
Antibiotic Resistant ◽  
Bacterial Diseases ◽  
Mar Index

The aquaculture industry is a fast-growing sector in Egypt; however, the progress of this industry is impeded by many challenges such as poor water quality and associated bacterial infections. Among others, Motile Aeromonas Septicemia (MAS), caused by aeromonads, is among the most important bacterial diseases affecting aquaculture due to its zoonotic potential. In the present work, motile aeromonads were isolated from water samples (n= 8) and Nile tilapia (n= 240) in four fish farms (farms I, II, III, and IV) in Kafr El-Sheikh province during the period March to August 2017. This step was followed by investigation of the prevalence and phenotypic, molecular, and histopathological characterization of aeromonads. In addition, antimicrobial susceptibility and virulence gene detection were analyzed. Interestingly, physicochemical water analysis revealed different ranges in relation to the fish farms and seasons. More importantly, Aeromonas isolates were phenotypically identified in 33.3% and 12.5% from fish and water samples, respectively. The highest prevalence of motile aeromonads (46.7%) was recorded from farm IV, and only 12.5% of water samples were positive for them. Out of 80 isolates, 65 (81.25%) were molecularly identified at the genus level using gyrase B (gyrB). The prevalence of the virulence genes detected in the isolated motile aeromonads was aerolysin (aer), 52.2%; elastase (ahp), 26.25%; hemolysin (hyl), 35%; and lipase (lip), 3.75%. The antibiogram profile revealed that the highest resistance of aeromonads isolates (80%) was recorded to chloramphenicol, kanamycin, and azithromycin. Meanwhile, lower resistance levels of 40%, 30%, and 20% were found for streptomycin, cefotaxime, and amoxicillin, respectively. The multiple antibiotic resistance (MAR) index values ranged between 0.27 and 0.82 of motile aeromonads isolates. Furthermore, the histopathological examinations of naturally diseased tilapia revealed widespread hepatocellular necrosis with diffuse, numerous rod-shaped bacteria in liver with melanomacrophages and lymphocytic depletion with edema and hemosiderosis in the spleen. Our findings provide an updated epidemiological baseline for future reference and highlight the likely role of the adverse impact of water quality in the outbreaks of motile aeromonads with special reference to virulence genes and antibiotic resistant traits.

Prevalence, molecular characterization, virulotyping, and antibiotic resistance of motile aeromonads isolated from Nile tilapia farms at northern Egypt

2020 ◽  
Vol 21 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Mona Salem ◽  
Eman Zahran ◽  
Rawia Saad ◽  
Viola Zaki
Keyword(s):  
Antibiotic Resistance ◽  
Molecular Characterization ◽  
Nile Tilapia ◽  
Management Practices ◽  
Virulence Genes ◽  
Disease Outbreaks ◽  
Resistance Pattern ◽  
Fish Farms ◽  
Critical Data ◽  
Mar Index

Objective: This study was aimed to survey Aeromonas spp associated with cultured Nile tilapia Oreochromis niloticus (O. niloticus) showing signs of motile Aeromonas septicemia (MAS) at different fish farms; molecular characterization and identification of test isolates; and to test the isolates for their antimicrobial and virulence activities that contribute to its pathogenesis. Design: Observational study Animals: 280 Nile tilapia Procedures: Clinically diseased 280 Nile tilapia, were collected from different localities at Kafr El-Sheik and Dakahlia governorates. The clinical picture and gross lesions were recorded. Aeromonas spp were isolated and presumptively identified using API20E. The identification was confirmed using PCR. Hemolysin (hylA), lipase, and aerolysin (aerA) virulence genes were detected among isolates obtained from different sampling sites. Besides, antimicrobial activity was reported for the identified A. hydrophila. Results: General septicemic signs were evident on Nile tilapia including, skin hemorrhages and ulcerations, bilateral exophthalmia, congested internal organs with significant mortalities. The prevalence of bacterial infection among naturally diseased Nile tilapia was 79.17, 70, and 58.33 in Kafr El-Sheikh, El- Manzala, and Gamsa fish farms, respectively. The most prevalent bacterial isolates were aeromonads (29.84 %), of all, 65.63 A. hydrophila, 18.75 A. caviae, and 15.63 A. sobria. All isolates were positively amplified using a species-specifying primer to determine A. hydrophila. Virulence genes detection revealed that five A. hydrophila isolates (83.3 %) harbored the aerA gene. Meanwhile, hylA and lipase genes positive isolates were lower reaching 16.7 % for both genes. A. hydrophila was highly sensitive to ciprofloxacin, amikacin, trimethoprim, and chloramphenicol, and MAR index of A. hydrophila isolates was ranged from 0.16-0.42 Conclusion and clinical relevance: Our findings demonstrate that Aeromonas spp are among the bacterial pathogens implicated in summer mortalities in tilapia fish farms in Egypt. Besides, determination of the prevalence, virulence genes, and antibiotic resistance pattern associated with the disease outbreaks is critical data that warrant the development of strategies to proper monitoring and farm management practices.

scholarly journals Bacteriophage activity against and characterisation of avian pathogenic Escherichia coli isolated from colibacillosis cases in Uganda

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0239107
Author(s):  
George Kazibwe ◽  
Phionah Katami ◽  
Ruth Alinaitwe ◽  
Stephen Alafi ◽  
Ann Nanteza ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Host Range ◽  
Bacterial Infections ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Economic Losses ◽  
Multi Drug Resistance ◽  
Avian Pathogenic Escherichia Coli ◽  
Alternative Strategies ◽  
Pathogenic Escherichia Coli

Avian Pathogenic Escherichia coli (APEC) cause colibacillosis leading to significant economic losses in the poultry industry. This laboratory-based study aimed at establishing stocks of avian pathogenic Escherichia coli lytic bacteriophages, for future development of cocktail products for colibacillosis management. The study determined the antibiotic susceptibility; phylogenetic categories, occurrence of selected serotypes and virulence genes among Escherichia coli stock isolates from chicken colibacillosis cases; and evaluated bacteriophage activity against the bacteria. Escherichia coli characterization was done through phenotypic and multiplex PCR methods. Bacteriophage isolation and preliminary characterization was achieved using the spot assay and overlay plating techniques. Fifty-six (56) isolates were phenotypically confirmed as E. coli and all exhibited resistance to at least one antimicrobial agent; while multi-drug resistance (at least three drugs) was encountered in 50 (89.3%) isolates. The APEC isolates mainly belonged to phylogroups A and D, representing 44.6% and 39.3%, respectively; whereas serotypes O1, O2 and O78 were not detected. Of the 56 isolates, 69.6% harbored at least one virulence gene, while 50% had at least four virulence genes; hence confirmed as APEC. Virulence genes, ompT and iutA were the most frequent in 33 (58.9%) and 32 (57.1%) isolates respectively; while iroN least occurred in 23 (41.1%) isolates. Seven lytic bacteriophages were isolated and their host range, at 1×108 PFU/ml, varied from 1.8% to 17.9% of the 56 APEC isolates, while the combined lytic spectrum was 25%. Phage stability was negatively affected by increasing temperatures with both UPEC04 and UPEC10 phages being undetectable at 70°C; whereas activity was detected between pH 2 and 12. The high occurrence of APEC isolates resistant against the commonly used antibiotics supports the need for alternative strategies of bacterial infections control in poultry. The low host range exhibited by the phages necessitates search for more candidates before in-depth phage characterization and application.

scholarly journals IMPACT OF WATER QUALITY ON THE BLOOD PARAMETERS OF NILE TILAPIA IN DIFFERENT FISH FARMS

2017 ◽  
Vol 44 (2) ◽  
pp. 571-581
Author(s):  
Mohammed Al-Zahaby ◽  
A. Shalaby ◽  
G. Abd-El-Rahman ◽  
M. Ayyat
Keyword(s):  
Water Quality ◽  
Nile Tilapia ◽  
Blood Parameters ◽  
Fish Farms

scholarly journals Bacteriophage therapy: experience from the Eliava Institute, Georgia

2008 ◽  
Vol 29 (2) ◽  
pp. 96 ◽  
Author(s):  
Nina Chanishvili ◽  
Richard Sharp
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Effective Means ◽  
Resistant Bacteria ◽  
Bacteriophage Therapy ◽  
Antibiotic Resistant ◽  
Bacterial Diseases ◽  
Wide Range

The lysis of bacteria by bacteriophage was independently discovered by Frederick Twort and Felix d?Herelle but it was d?Herelle who proposed that bacteriophage might be applied to the control of bacterial diseases. Within the former Soviet Union (FSU), bacteriophage therapy was researched and applied extensively for the treatment of a wide range of bacterial infections. In the West, however, it was not explored with the same enthusiasm and was eventually discarded with the arrival of antibiotics. However, the increase in the incidence of multi-antibiotic-resistant bacteria and the absence of effective means for their control has led to increasing international interest in phage therapy and in the long experience of the Eliava Institute. The Eliava Institute of Bacteriophage, Microbiology and Virology (IBMV), which celebrates its 85th anniversary in 2008, was founded in Tbilisi in 1923 through the joint efforts of d?Herelle and the Georgian microbiologist, George Eliava.

scholarly journals Bacteriophage activity against and characterisation of avian pathogenic Escherichia coli isolated from colibacillosis cases in Uganda

2020 ◽  
Author(s):  
George Kazibwe ◽  
Phionah Katami ◽  
Ruth Alinaitwe ◽  
Stephen Alafi ◽  
Ann Nanteza ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Host Range ◽  
Bacterial Infections ◽  
Virulence Genes ◽  
Production Systems ◽  
Virulence Gene ◽  
Poultry Production ◽  
Antimicrobial Drugs ◽  
Pathogenic Escherichia Coli ◽  
Phenotypic Tests

AbstractA laboratory-based study aimed at establishing a stock of avian pathogenic Escherichia coli (APEC) lytic bacteriophages, for future development of cocktail products for controlling colibacillosis as well as minimizing use of antimicrobial drugs in the poultry production systems in Uganda. Specifically, the study determined the antibiotic susceptibility; phylogenetic categories, occurrence of selected virulence genes among Escherichia coli stock isolates from cases of chicken colibacillosis; and isolation of specific bacteriophages. Fifty six isolates were confirmed as E. coli by standard phenotypic tests. All the 56 (100%) isolates were resistant to at least one antibiotic while 50 (89.3%) isolates were resistant to at least three classes of antimicrobial drugs and were therefore designated as multi-drug resistant. Phylogenetically, APEC isolates mainly belonged to phylogroups A and D which represented 44.6% and 39.3%, respectively. Virulence genes, ompT and iutA were the most frequent with 33 (58.9%) and 32 (57.1%) isolates respectively; while iroN least occurred in 23 (41.1%) isolates. Of the 56 isolates, 69.6% harbored at least one virulence gene, while 50% had at least four virulence genes; hence confirmed as APEC. None of the isolates belonged to the selected serotypes O1, O2 and O78. Seven specific bacteriophages were isolated and their host range, varied from 1.8% to 17.9% (n=56 APEC isolates), while the combined lytic spectrum of all the phages was 25%. Phage stability was negatively affected by increasing temperatures with both UPEC04 and UPEC10 phages becoming undetectable at 70°C; however activity was detected between pH 2 and 12. The high occurrence of APEC isolates with resistance against the commonly used antibiotics supports the need for alternative strategies of bacterial infections control in poultry. The low host range exhibited by the phages calls for search for more candidates before more in-depth studies are done for phage characterization and application.

scholarly journals Dental unit water lines: The infectious sources of Pseudomonas aeruginosa

2012 ◽  
Vol 4 (2) ◽  
pp. 200-203
Author(s):  
Ashok V. Gomashe ◽  
Pranita A. Gulhane ◽  
Preeti G. Dharmik ◽  
Aparna K. Barhanpure
Keyword(s):  
Water Quality ◽  
Pseudomonas Aeruginosa ◽  
Water Samples ◽  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Healthcare Personnel ◽  
Distilled Water ◽  
Antibiotic Susceptibility Testing ◽  
Water Spray ◽  
Antibiotic Resistant

Water quality in the dental unit water lines (DUWLs) is important to the patients and dental healthcare personnel as they are at risk of being infected with Pseudomonas aeruginosa. The aim of the present study was to determine the occurrence of P. aeruginosa contamination in DUWLs and to study the antibiotic resistant profile. A total of 101 dental water samples including air/water spray (26), Ultrasonic scalar (24), Air rotor compressor (26) and Distilled water (25) were screened for P. aeruginosa and 67 samples were found to be contaminated by P. aeruginosa. All these isolates were further subjected to antibiotic susceptibility testing. Among these, 63 (94.02%) showed resistance to ampicillin followed by 39 (58.20%) to amoxicillin, 11 (16.41%) to cefepime, 5 (7.46%) to aztreonam and 1 (1.49%) to gentamicin.

scholarly journals Tailored Liposomal Nanotraps for the Treatment of Streptococcal Infections

2020 ◽  
Author(s):  
Hervé Besançon ◽  
Viktoriia Babiychuk ◽  
Yu Larpin ◽  
René Köffel ◽  
Dominik Schittny ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Diagnostic Delay ◽  
Host Cells ◽  
Streptococcal Toxic Shock Syndrome ◽  
Streptococcal Infections ◽  
Antibiotic Resistant ◽  
Bacterial Diseases ◽  
Life Threatening ◽  
Streptococcus Dysgalactiae Subspecies Equisimilis ◽  
Pathogen Clearance

Abstract Background: Streptococcal infections are associated with life-threatening pneumonia and sepsis. The rise in antibiotic resistance calls for novel approaches to treat bacterial diseases. Anti-virulence strategies promote a natural way of pathogen clearance by eliminating the advantage provided to bacteria by their virulence factors. In contrast to antibiotics, anti-virulence agents are less likely to exert selective evolutionary pressure, which is a prerequisite for the development of drug resistance. As part of their virulence mechanism, many bacterial pathogens secrete cytolytic exotoxins that destroy the host cell by destabilizing their plasma membrane. Liposomal nanotraps, mimicking plasmalemmal structures of host cells that are specifically targeted by bacterial toxins are being developed in order to neutralize - by competitive sequestration - numerous exotoxins. Results: In this study, the liposomal nanotrap technology is further developed to simultaneously neutralize the whole palette of cytolysins produced by Streptococcus pneumoniae, Streptococcus pyogenes and Streptococcus dysgalactiae subspecies equisimilis - pathogens that can cause life-threatening streptococcal toxic shock syndrome. We show that the mixture of liposomes containing high amounts of cholesterol and liposomes composed exclusively of choline-containing phospholipids is fully protective against the combined action of exotoxins secreted by these pathogens. Conclusions: Unravelling the universal mechanisms that define targeting of host cells by streptococcal cytolysins paves the way for a broad-spectrum anti-toxin therapy that can be applied without a diagnostic delay for the treatment of bacterial infections including those caused by antibiotic-resistant pathogens.

scholarly journals Virulence genes of Aeromonas isolates, bacterial endotoxins and cyanobacterial toxins from recreational water samples associated with human health symptoms

2011 ◽  
Vol 9 (4) ◽  
pp. 670-679 ◽  
Author(s):  
Katri A. Berg ◽  
Christina Lyra ◽  
R. Maarit Niemi ◽  
Benoit Heens ◽  
Kalle Hoppu ◽  
...  
Keyword(s):  
Human Health ◽  
Health Effects ◽  
Water Samples ◽  
Virulence Genes ◽  
Gastrointestinal Symptoms ◽  
Virulence Gene ◽  
Health Symptoms ◽  
Adverse Health Effects ◽  
Adverse Health ◽  
Bacterial Endotoxins

Exposure to cyanobacterial water blooms has been associated with various kinds of adverse health effects. In addition to cyanobacteria and their toxins, the bacteria associated with cyanobacteria could also be the etiological agents. We isolated Aeromonas strains (n = 176) from water samples (n = 38) taken from sites where cyanobacteria were suspected to have caused human health symptoms, of which fever and gastrointestinal symptoms were the most common. The isolates were screened by PCR for six virulence gene types (12 genes). The majority (90%) of the strains contained at least one of the virulence genes. Most common amplification products were those of genes (act/aerA/hlyA) that encode cytotoxic enterotoxin and haemolytic products. The genes encoding cytotonic enterotoxins (ast and alt), phospholipase (lip/pla/lipH3/alp-1), elastase (ahyB) and flagellin subunits (flaA/flaB) were also present in 5–37% of the Aeromonas strains. Analysed toxins (cyanobacterial hepatotoxins and neurotoxins, and bacterial endotoxins) were not detectable or were present in only low concentrations in the majority of the samples. The results indicated that the toxins were unlikely to be the main cause of the reported adverse health effects, whereas more attention should be paid to bacteria associated with cyanobacteria as a source of health effects.

scholarly journals Tailored Liposomal Nanotraps for the Treatment of Streptococcal Infections

2021 ◽  
Author(s):  
Hervé Besançon ◽  
Viktoriia Babiychuk ◽  
Yu Larpin ◽  
René Köffel ◽  
Dominik Schittny ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Diagnostic Delay ◽  
Host Cells ◽  
Streptococcal Toxic Shock Syndrome ◽  
Streptococcal Infections ◽  
Antibiotic Resistant ◽  
Bacterial Diseases ◽  
Life Threatening ◽  
Streptococcus Dysgalactiae Subspecies Equisimilis ◽  
Pathogen Clearance

Abstract Background: Streptococcal infections are associated with life-threatening pneumonia and sepsis. The rise in antibiotic resistance calls for novel approaches to treat bacterial diseases. Anti-virulence strategies promote a natural way of pathogen clearance by eliminating the advantage provided to bacteria by their virulence factors. In contrast to antibiotics, anti-virulence agents are less likely to exert selective evolutionary pressure, which is a prerequisite for the development of drug resistance. As part of their virulence mechanism, many bacterial pathogens secrete cytolytic exotoxins (hemolysins) that destroy the host cell by destabilizing their plasma membrane. Liposomal nanotraps, mimicking plasmalemmal structures of host cells that are specifically targeted by bacterial toxins are being developed in order to neutralize - by competitive sequestration - numerous exotoxins. Results: In this study, the liposomal nanotrap technology is further developed to simultaneously neutralize the whole palette of cytolysins produced by Streptococcus pneumoniae, Streptococcus pyogenes and Streptococcus dysgalactiae subspecies equisimilis - pathogens that can cause life-threatening streptococcal toxic shock syndrome. We show that the mixture of liposomes containing high amounts of cholesterol and liposomes composed exclusively of choline-containing phospholipids is fully protective against the combined action of exotoxins secreted by these pathogens. Conclusions: Unravelling the universal mechanisms that define targeting of host cells by streptococcal cytolysins paves the way for a broad-spectrum anti-toxin therapy that can be applied without a diagnostic delay for the treatment of bacterial infections including those caused by antibiotic-resistant pathogens.

scholarly journals Delineating the key virulence factors and intraspecies divergence of Vibrio harveyi via whole-genome sequencing

2020 ◽  
pp. 1-18
Author(s):  
Songzhe Fu ◽  
Ping Ni ◽  
Qian Yang ◽  
Huizhi Hu ◽  
Qingyao Wang ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Virulence Factors ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Virulence Gene ◽  
Field Investigation ◽  
Whole Genome ◽  
Type Vi Secretion System ◽  
Fish Farms

Vibrio harveyi is one of the major pathogens in aquaculture. To identify the key virulence factors affecting pathogenesis of V. harveyi towards fish, we conducted a field investigation for three representative fish farms infected with V. harveyi. Multilocus sequence typing (MLST) and whole-genome sequencing were conducted to delineate the phylogenetic relationship and genetic divergence of V. harveyi. A total of 25 V. harveyi strains were isolated from the diseased fish and groundwater and were subtyped into 12 sequence types by MLST. Five virulence genes, mshB, pilA, hutR, ureB, and ureG, were variably presented in the sequenced strains. The virulence gene profiles strongly correlated with the distinct pathogenicity of V. harveyi strains, with a strain harboring all five genes exhibiting the highest virulence towards fish. Phenotype assay confirmed that reduced virulence correlated with decreased motility and biofilm formation ability. Additionally, three types of type VI secretion system, namely T6SS1, T6SS2, and T6SS3, were identified in V. harveyi strains, which can be classified into six, four, and 12 subtypes, respectively. In conclusion, the results indicated that the virulence level of V. harveyi is mainly determined by the above virulence genes, which may play vital roles in environmental adaptation for V. harveyi.

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