Aeromonas a new emerging pathogen isolated from water and foods

1,094 views
828 views

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,094
On SlideShare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
25
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Aeromonas a new emerging pathogen isolated from water and foods

  1. 1. Aeromonas: A New Emerging Pathogen Isolated from Water and Foods Khalifa Sifaw Ghenghesh Dept. of Microbiology and Immunology Faculty of Medicine, Tripoli University, Tripoli - Libya
  2. 2. INTRODUCTION • Gram-negative, oxidase-positive, facultative anaerobic, rod-shaped bacteria. • Almost all strains grow on MacConkey agar and some are lactosepositive. • Habitat: – Natural waters • Clinical Infections: – Bacteremia: • Particularly in the immunocompromised. – Wound infections: • exposure to water – Gastroenteritis: • Controversial ? • Epidemiological evidence – Some strains are causes of diarrhea – Others
  3. 3. • Virulence Factors: – Exotoxins – Invasiveness – Adherence – Others • Antibiotic Resistance: - β-lactams
  4. 4. • Taxonomy – Last edition of Bergy's Manual: • 17 hybridization groups (HG) or genospecies (Based on DNA-DNA reassociation) and • 14 phenospecies placed in the family Aeromonadaceae. • A. caviae, A. hydrophila and A. veronii bv. sobria • A. trota • Sources: – Water – Foods
  5. 5. Hybridization groups (genospecies) and phenospecies of Aeromonas and their isolation from different sources in developing countries. Hybridization Genospecies groups (HG) Phenospecies Isolation from:a Clinical specimens Food Water ------------------------------------------------------------------------------------------------------------------------------------------------1 A. hydrophila A. hydrophila C C C 2 A. bestiarum A. hydrophila-like NR R NR 3 A. salmonicida* A. salmonicida NR C NR 3 Unnamed A. hydrophila-like NR NR NR 4 A. caviae A. caviae C C C 5A A. media A. caviae-like NR NR NR 5B A. media A. media R R R 6 A. eucrenophila A. eucrenophila NR R R 7 A. sobria A. sobria NR NR NR 8X A. veronii A. sobria NR NR NR 8Y A. veronii A. veronii.biovar sobria C C C 9 A. jandaei A. jandaei R NR NR 10 A. veronii A. veronii biovar veronii R NR NR 11 Unnamed Aeromonas sp. NR NR NR 12 A. schubertii A. schubertii R NR NR 13 Unnamed A. schubertii-like NR NR NR 14 A. trota A. trota R R R 15 A. allosaccharophila NR NR NR 16 A. encheleia NR R NR 17 A. popoffii NR NR NR -----------------------------------------------------------------------------------------------------------------------------------------------a C=common, R=rare, and NR=not reported.
  6. 6. Prevalence of Aeromonas sp. in diarrheic and non diarrheic children in some developing countries Country %positive /no examined Diarrheic P value Dominant species Non diarrheic ---------------------------------------------------------------------------------------------------------------Bangladesh 9.2/814 3.0/814 <0.0001 NA* Brazil 19/100 13/100 NS A. Caviae Brazil 21.9/9 10/72 <0.0001 A. Caviae China 5.9/221 9.3/108 NS NA Cuba 9.0/300 NA A. hydrophila Egypt 88/NA 45/NA NA India 4.7/341 0/147 <0.01 A. Caviae India 9.7/216 NA NA Iran 4.5/310 0/310 <0.0001 A. veronii bv sobria Libya 15/157 18/157 NS A. Caviae Nigeria 1.0/100 NA A. hydrophila Venezuela 11.8/397 5.8/121 A. Caviae Vietnam 15/291 8.0/291 NS NA ----------------------------------------------------------------------------------------------------------------------------*NA=not available
  7. 7. Aeromonas-associated outbreaks • Foodborne outbreaks: – In China: 115 individuals resulting from consumption of pork contaminated with A. hydrophila. – Several outbreaks due to seafoods. • Nosocomial outbreaks: – In India: 6 children in hematology-oncology unit with acute watery diarrhea due to A. veronii bv. sobria. – In Libya: 28 patients with gastroenteritis due to A. veronii bv. sobria.
  8. 8. Laboratory Diagnosis • Samples: – Stool, food, water. • Media: – Alkaline peptone water (pH 8.5, APW) • Enrichment medium – Ampicillin blood agar (10 mg/L, ABA) – Other media available commercially: • Aeromonas Agar • CIN medium • Isolation from: – Stool: • • • • add 1g stool to 10ml APW and incubate overnight at 37oC. Take a loopful of APW and plate on ABA. Suspected colonies tested for oxidase. Oxidase-positive colonies identified biochemically.
  9. 9. • Food: – add 25g of foods to 250ml of APW and then follow as previously described. • Water: – Add 25ml of water to 250ml of APW and then follow as previously described. • Notes: – Most of Aeromonas strains are either β- or α-hemolytic on BA. – Some species are sensitive to ampicillin
  10. 10. Aeromonas in Libya • Aeromonas-Associated Diarrhoea – in Children – in Adults • Cholera-like diarrhoea • Other Clinical Infections:
  11. 11. Prevalence of Aeromonas in children in Tripoli and Zliten ---------------------------------------------------------------------------Patients No. No. (%) tested Positive ---------------------------------------------------------------------------Children (Tripoli): - with diarrhoea 157 24(15%) - without diarrhoea 157 28(18%) Children (Zliten) -with diarrhoea 169 9(5%) ----------------------------------------------------------------------------
  12. 12. Distribution of Aeromonas species among patients and controls _______________________________________________________________ No. (%) belonging to the following Aeromonas species: Subjects No. hydrophila veronii caviae schubertii Total tested bv sobria --------------------------------------------------------------------------------------------------------Patients 157 5(3.2)* 8(5.1) 13(8.3) 1(0.6) 27(17.2) Controls 157 9(5.7) 7(4.5) 17(10.8) 2(1.2) 35(22.3 _______________________________________________________________ *No. positive (%)
  13. 13. Haemolytic and haemagglutination activities of Aeromonas species isolated from children with diarrhoea (cases) and controls. _______________________________________________________________ Number of strains (%) positive for: Haemolysin Haemagglutination Subjects No. strains MS* MR tested Cases 27 11(41) 15(56) 7(26)# Controls 35 11(31) 15(43) 1(3) ______________________________________________________________ *MS= mannose sensitive; MR= mannose resistant. #(P<0.01; Fisher's exact test).
  14. 14. Aeromonas in Libya • In Animals – in Cows and Camels – in Dogs and Cats – in Cockroaches – in Housefly – in Ostriches
  15. 15. Occurrence of Aeromonas in animals in Libya ________________________________________________________ Animal No. tested No. (%) positive ---------------------------------------------------------------------------------------------Cows 36 0(0) Camles 200 1(0.5) Ostriches 6 1(17)* Domestic dogs 120 13(11) Domestic cats 15 1 (7%) Housflies 150 16(11) Cockroaches 150 2(1.3) ________________________________________________________ *animal with diarrhoea.
  16. 16. Aeromonas in Libya • In Foods: – in Fish – in Chicken Carcasses – in Meats – in Ice Cream – in Libyan Made Juices
  17. 17. Aeromonas in foods in Libya ___________________________________________________ Food No. tested No. (%) positive ------------------------------------------------------------------------------------Fish 48 20 (42) Chicken carcases 290 218 (75) Meats: camel 18 12 (67) beef 50 19 (38) Total 68 31 (46) Ice cream 160 30 (19) Juices 147 3 (2.1) ___________________________________________________
  18. 18. Aeromonas in Libya • In Water: – in Well Water – in Majin water – in Mineral Water
  19. 19. Aeromonas in water in Libya _______________________________________ Type of No. No. (%) Water tested positive ----------------------------------------------------------------Well 1000 487 (49) Majin 62 37 (60) Mineral 216 0 (0.0) _______________________________________
  20. 20. Speciation of 381 Aeromonas Strains Isolated from Untreated Water. ----------------------------------------------------------------Species No. (%) isolated ----------------------------------------------------------------A. hydrophila 225 (59%) A. caviae 103 (27%) A. veronii bv sobria 42 (11%) atypical 11 (3%) aeromonads ----------------------------------------------------------------Total tested 381(100) ------------------------------------------------------------------
  21. 21. Seasonal Distribution of Aeromonas Species isolated from untreated water. -------------------------------------------------------------------Season No. Samples No. (%) Tested Isolated -------------------------------------------------------------------Spring 60 27 (45) Summer 284 98 (34.5) Autumn 313 150 (48) Winter 343 205 (60) --------------------------------------------------------------------
  22. 22. Hemolytic activity of Aeromonas species isolated from well water in Tripoli area. _______________________________________________________________ % of Aeromonas species showing haemolysis Erythrocytes hydrophila caviae veronii bv. Total sobria used (n=52) (n=93) (n=26) (n=170) _________________________________________________________ Human 67 34 88 53 Horse 62 30 88 49 Sheep 52 25 73 40 Camel 52 22 65 37 Mean value* 58 28 79 45 _________________________________________________________ * Mean value for the sum of all assays.
  23. 23. PCR Detection of Genes coding for virulence factors in Aeromonas act: Aeromonas Cytolytic Enterotoxin ast: Aeromonas hydrophila Isolate SSU Enterotoxin aer: Aerolysin alt: Aeromonas Extracellular Lipase
  24. 24. Genes coding for virulence factors in Aeromonas from Libya No (%) positive for No of Strains act ast aer lip ----------------------------------------------------------------------------------------------Aeromonas from: Children: - with diarrhea 12 0 0 10 (83) 0 - without diarrhea 12 0 0 10 (83) 0 Well water 11 4 (36) 6 (55) 9 (82) 0 Chicken 17 0 3 (18) 16 (94) 0 ---------------------------------------------------------------------------------------------Total 52 4 (8) 9 (17) 45 (87) 0
  25. 25. Antibiotic Sensitivity of Aeromonas Strains Isolated from Different Sources. ----------------------------------------------------------------------------------------------------% Resistance of Aeromonas from Antibiotic Children Water Chicken (62)* (40) (59) ----------------------------------------------------------------------------------------------------Amoxicillin + 97 93 100 clavulanic acid Chloramphenicol 6 0.0 12 Ciprofloxacin 0.0 0.0 2 Gentamicin 0.0 0.0 3 Kanamycin 3 0.0 9 Nalidixic acid 0.0 0.0 37 Tetracycline 11 5 58 Trimethoprim23 0.0 53 sulphamethoxazole -----------------------------------------------------------------------------------------------------

×