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Foodborne illnesses in developing countries

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Foodborne illnesses in developing countries

  1. 1. Pathogens-Associated with Foodborne Illnesses in Developing Countries Prof. Khalifa Sifaw Ghenghesh Dept. of Microbiology and Immunology, Faculty of Medicine, Tripoli University, Tripoli Libya
  2. 2. Introduction National surveillance programs for pathogens associated with foodborne illnesses generally do not exist in most developing countries despite the substantial burden of disease. Most estimates of incidence in developing countries are from laboratory-based surveillance of pathogens responsible for diarrhea.
  3. 3. Pathogens-associated with foodborne illnesses  Bacterial:  Bacillus cereus  Campylobacter sp.  Clostridium botulinum  Clostridium perfringens  Diarrheagenic Escherichia coli: E. coli O157:H7  Listeria monocytogenes  Salmonella sp.  Shigella sp.  Staphylococcus aureus  Vibrio cholerae  Yersinia sp.  Viral:  Hepatitis A  Norovirus  Rotavirus  Parasitic:  Entamoeba histolytica  Giardia lamblia  Cryptosporidium sp.
  4. 4. Salmonella S. typhi and S. paratyphi  Typhoid fever Non-typhoid Salmonella  Salmonellosis  > 2,000 named serotypes (serovars). Based on iso-enzymes, rRNA sequences, and DNA hybridization, it is generally accepted now that there is only a single species of Salmonella > S. enterica  > S. enterica serotype Typhimurium  Most common: S. Enteritidis > in developed countries S. Typhimurium S. Heidelberg?
  5. 5. Shigella Shigellosis 4 Major O Antigenic Groups: Serogroup A = Sh. dysenteriae Serogroup B = Sh. flexneri Serogroup C = Sh. boydii Serogroup D = Sh. sonnei :
  6. 6. Campylobacter Campylobacteriosis:  > 16 species C. jejuni and C. coli
  7. 7. Salmonella, Shigella and Campylobacter in Developing Countries
  8. 8. Isolation rates of Salmonella, Shigella and Campylobacter from diarrhea specimens from children in selected developing countries                Argentina Bangladesh Brazil Egypt Guatemala Indonesia Jordan Kuwait Lao PDR Libya Pakistan Saudi Arabia Thailand Tunis Zimbabwe Isolation rate (%) Salmonella Shigella Campylobacter 2.4 8.5 3.2 1.8 9.2 17.4 2.2 6.2 5.4 7 5 7 NA 9.8 12.1 2.5 4.2 0.4 3.9 8.3 5.6 24 4 7 0.6 16.8 4.4 11 5.7 6.3 6.6 6.2 17.3 10.5 17.1 NA 12 13 13 2.4 4.1 4.7 5.4 13.5 1.3
  9. 9. Distribution of Salmonella serotypes:  S. Typhimurium  S. Enteritidis  Other serotypes: Differs from one country to another
  10. 10. Salmonella Serotypes Isolated from Diarrheic Faeces in Tripoli (1975-1980) S. Wien S. Muenchen S. Typhimurium Salmonella Serotypes Isolated from Children with Diarrhea in Tripoli (1992-1993) S. Saintpaul S. Muenchen Salmonella Serotypes Isolated from Children with Diarrhea in Zliten (2000-2001) S. Heidelberg S. Enteritids
  11. 11. Distribution of Shigella groups:  Sh. flexneri Distribution of Campylobacter species:  C. jejuni and C. coli are the two main species isolated in developing countries.  Similar to observations in developed countries, the isolation rate of C. jejuni exceeds that of C. coli.
  12. 12. Age of Infection:  Most commonly isolated from <2-year-old children with diarrhea.  Shigella? Polymicrobial Infections:  Campylobacter > common Isolation in Healthy Children:  Campylobacter > common  Shigella > rare
  13. 13. Seasonal Variation:  Contrary to developed countries, diarrhea due to Salmonella, Shigella or Campylobacter, has no seasonal preference in developing countries.  Lack of seasonal preference may be due to: lack of extreme temperature variation lack of adequate surveillance for epidemics. Association with travelers' diarrhea:  Travel to a developing country is a risk factor for acquiring Salmonella-, Shigella- or Campylobacterassociated diarrhea.  The diarrhea is more severe, and strains are associated with antibiotic resistance.
  14. 14. Antibiotic resistance in Salmonella, Shigella and Campylobacter isolates:  Resistance is high in developing countries.  Salmonella and Campylobacter enteritis are selflimiting diseases, and antimicrobial therapy is not generally recommended.  Shigella Patients respond to antibiotics. disease duration diminished.
  15. 15. Resistance of Salmonella species isolated from children with diarrhoea in Zliten (2000- 2001) to antibiotics Antibiotic No. (%) resistant: (n=23) --------------------------------------------------------------------------------Ampicillin 23 (100) Amoxicillin+calvulanic acid 22 (95.7) Cefoxitin 20 (87) Gentamicin 18 (78.3) Doxycycline 21 (91.3) Chloramphenicol 22 (95.7) Nalidixic acid 1 (4.3) Norfloxacin 0 (0.0) Trimethoprim-sulphamehtoxazole 1 (4.3) _________________________________________________
  16. 16. Sources of Salmonella, Shigella and Campylobacter Shigella and S. Typhi: Man is the only reservoir. Campylobacter and non-typhoid Salmonella:  Animals products: Chicken eggs Meat Dairy products Others:
  17. 17. Total bacterial and coliform counts and pathogenic bacteria isolated from ice cream sold in Tripoli—Libya Ice cream Bacteria Open Packed Total (n = 111) (n = 49) (n = 160) --------------------------------------------------------------------------------------------------E. coli 7 (6)a 3 (6) 10 (6) Salmonella sp. 7 (6) 1 (2) 8 (5) Shigella sp. Absent Absent Absent Aeromonas sp. 20 (18) 10 (20) 30 (19) S. aureus 41 (37) 19 (39) 60 (38) L. moncytogenes 7 (6) Absent 7 (4) --------------------------------------------------------------------------------------------------a No. (%) positive.
  18. 18. Bacteria isolated from the houseflies collected in Misurata - Libya Collection site: Bacteria Central Hospital City streets Abattoir All (n=50)a (n=50) (n=50) (n=150) ----------------------------------------------------------------------------------------------------------------Escherichia coli 21 (42)b 21 (42) 16 (32) 58 (38.7) Salmonella sp. 0 (0) 3 (6) 1 (2) 4 (2.7) Shigella sonnei 0 (0) 0 (0) 1 (2) 1 (0.7) Yersinia enterocolitica 0 (0) 2 (4) 1 (2) 3 (2.0) Edwardsiella tarda 0 (0) 2 (4) 1 (2) 3 (2.0) Aeromonas sp. 1 (2) 10 (20) 5 (10) 16 (10.7) Pseudomonas sp. 48 (96) 18 (36) 17 (34) 78 (52) Pasteurella sp. 0 (0) 1 (2) 2 (4) 3 (2.0) Staphylococcus sp. 10 (20) 6 (12) 8 (16) 24 (16.0) Streptococcus sp. 12 (24) 11 (22) 9 (18) 32 (21.3) --------------------------------------------------------------------------------------------------------------a No. of flies investigated b No (%) positive

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