3/13/2016 Learning Objectives Food 1.Use basic biochemical characteristics to identify Staphylococcus aureus 2.Understand what conditions in foods favor 5. aureus growth Chapter 16 AN INTRODUCTION 3.Recognize,from symptoms and time of onset,a case of foodborne illness caused by5.aureus Staphylococcus 4.Choose appropriate interventions(heat, aureus preservatives,and formulations)to prevent the growth of 5.aureus 5.Identify sources of 5.aureus 6.Understand the roles of staphylococcal enterotoxins in causing foodborne illness Outbreak Outbreak Flight of horror Flight of horror Flight left Alaska and passengers were served breakfast .80%of passengers had diarrhea Breakfast was an omelet with ham and .70%of passengers had vomiting cheese ·85%had nausea About 30 min after eating,a passenger The"discomfort bags"ran out rushed to the rear of the plane vomiting on passengers before reaching the toilet After landing,rectal swabs were done Most of the passengers streamed for the on some passengers and tested positive 4 available toilets for Staphylococcus aureus and its toxin 250 passengers with vomiting and diarrhea 5.aureus and toxin were also found in and only 4 toilets the ham and cheese
3/13/2016 1 Chapter 16 Staphylococcus aureus Learning Objectives 1. Use basic biochemical characteristics to identify Staphylococcus aureus 2. Understand what conditions in foods favor S. aureus growth 3. Recognize, from symptoms and time of onset, a case of foodborne illness caused by S. aureus 4. Choose appropriate interventions (heat, preservatives, and formulations) to prevent the growth of S. aureus 5. Identify sources of S. aureus 6. Understand the roles of staphylococcal enterotoxins in causing foodborne illness Outbreak Flight of horror • Flight left Alaska and passengers were served breakfast • Breakfast was an omelet with ham and cheese • About 30 min after eating, a passenger rushed to the rear of the plane vomiting on pg g assengers before reaching the toilet • Most of the passengers streamed for the 4 available toilets • 250 passengers with vomiting and diarrhea and only 4 toilets Outbreak Flight of horror • 80% of passengers had diarrhea • 70% of passengers had vomiting • 85% had nausea • The “discomfort bags” ran out • After landing, rectal swabs were done on d t t d iti some passengers and tested positive for Staphylococcus aureus and its toxin • S. aureus and toxin were also found in the ham and cheese
3/13/2016 Outbreak Outbreak Flight of horror Flesh-eating bacteria Meal had been prepared 14 h earlier Methicillin-resistant and held at room temperature 5.aureus (MRSA)are It was held at inadequate temperature usually hospital-acquired infections during flight and microwaved before These infections can also be acquired by serving food. When public health officials A family bought shredded barbecued shook hands with the head pork at a deli,heated in the microwave chef,they found a pus-filled and ate it boil on his hands 3-4 hours later,3 became ill with Guess what they found? vomiting and nausea Outbreak Outbreak Flesh-eating bacteria Flesh-eating bacteria Those who did not eat the pork did not The strain isolated was MRSA and become ill produced staphylococcal enterotoxin C Two were treated at the hospital Different and multiple isolates of 5. aureus were isolated from their stools the pork nasal swabs from three food handlers at the deli
3/13/2016 2 Outbreak Flight of horror • Meal had been prepared 14 h earlier and held at room temperature • It was held at inadequate temperature during flight and microwaved before serving • When public health officials shook hands with the head chef, they found a pus-filled boil on his hands • Guess what they found? Outbreak Flesh-eating bacteria • Methicillin-resistant S aureus S. aureus (MRSA) are usually hospital-acquired infections • These infections can also be acquired by food. • A family bought shredded barbecued pork at a deli heated in the microwave pork at a deli, heated in the microwave and ate it • 3-4 hours later, 3 became ill with vomiting and nausea Outbreak Flesh-eating bacteria • Those who did not eat the pork did not b ill become ill • Two were treated at the hospital • Different and multiple isolates of S. aureus were isolated from - their stools - the pork - nasal swabs from three food handlers at the deli Outbreak Flesh-eating bacteria • The strain isolated was MRSA and prod d t h l l duced staphylococcal ent ti ero oxin C
3/13/2016 Characteristics of the Organism Characteristics of the Organism Historical Aspects General Properties 1914,first link between 5.aureus and Golden yellow colonies foodborne illness Excretes a variety of compounds -Researchers found that drinking -Includes enterotoxins contaminated milk caused vomiting Toxins cause two human diseases and diarrhea toxic shock syndrome 1930-Dack and coworkers consumed fluids with 5.aureus that was isolated -staphylococcal food poisoning from cake and became ill with vomiting. abdominal pain and diarrhea Characteristics of the Organism Characteristics of the Organism Main agent of staphylococcal food Outbreaks are caused by foods in which poisoning the organism was killed but the toxin Caused by ingesting staphylococcal remained toxins that were previously produced in Staphylococcal toxin is not destroyed the food by heating or canning Intoxication-does not require that the bacteria infect the victim
3/13/2016 3 Characteristics of the Organism Historical Aspects • 1914 fi t li k b t 1914, first link between S . aureus and foodborne illness - Researchers found that drinking contaminated milk caused vomiting and diarrhea • 1930 – Dack and coworkers consumed fluids with S. aureus that was isolated from cake and became ill with vomiting, abdominal pain and diarrhea Characteristics of the Organism General Properties • Golden yellow colonies • Excretes a variety of compounds - Includes enterotoxins • Toxins cause two human diseases - toxic shock syndrome - staphylococcal food poisoning Characteristics of the Organism • Main agent of staphylococcal food poi i son ng • Caused by ingesting staphylococcal toxins that were previously produced in the food • Intoxication – does not require that the bacteria infect the victim Characteristics of the Organism • Outbreaks are caused by foods in which th i kill d b t th t i the organism was killed but the toxin remained • Staphylococcal toxin is not destroyed by heating or canning
3/13/2016 Characteristics of the Organism Wall teichoic acid (WTA)of to partially mediate the binding Sources of Staphylococcal Food Contamination People are the main reservoir of 5. aureus Humans are natural carriers that spread 5.aureus to food and to other people Nose is the main colonization site but also occurs on the skin Characteristics of the Organism Characteristics of the Organism ·Spreads by Direct contact Conditions associated with outbreaks -Skin fragments inadequate refrigeration -Respiratory droplets preparing foods too far in advance -poor personal hygiene Most food poisoning is traced by to those preparing the food inadequate cooking or heating of food Contamination may also occur via prolonged use of warming plates contaminated kitchen utensils and food wehen serving foods preparation equipment and surfaces
3/13/2016 4 Characteristics of the Organism Sources of Staphylococcal Food C t i ti Contamination • People are the main reservoir of S. aureus • Humans are natural carriers that spread S aureus S. aureus to food and to other people • Nose is the main colonization site but also occurs on the skin Wall teichoic acid (WTA) of S. aureus seems to partially mediate the binding Characteristics of the Organism • Spreads by - Direct contact - Skin fragments - Respiratory droplets • Most food poisoning is traced by to those prepar those prepar ng the food ing the food • Contamination may also occur via contaminated kitchen utensils and food preparation equipment and surfaces Characteristics of the Organism • Conditions associated with outbreaks - inad f equate refrigeration - preparing foods too far in advance - poor personal hygiene - inadequate cooking or heating of food - prolonged use of warming plates wehen serving foods
3/13/2016 Characteristics of the Organism Characteristics of the Organism Animals may also be sources 5.aureus is present in many food types -Mastitis(infection of cow teats)is a -Various meat products serious problem for the dairy -Various fish products industry Bovine mastitis is the single most -Assorted cream pies costly agricultural disease in the US Tuna pot pies -Mastitis is a public health concern as Deli salads bacteria can contaminate milk and Bacterial load is usually low<100 CFU/g dairy products Bacteria can grow to>106 CFU/g Controlled by strict hygiene Characteristics of the Organism Characteristics of the Organism Resistance to Adverse Environmental As there are so many human and animal Conditions reservoirs,controlling staphylococcal infections is challenging Unique resistance to inhibitors ·Grows with high salt Grows with low water activity of 0.86 under aerobic conditions (anaerobic 0.90) cured meats -puddings -sauces
3/13/2016 5 Characteristics of the Organism • Animals may also be sources - Mastitis (infection of cow teats) is a seri bl f th d i ious problem for the dairy industry - Bovine mastitis is the single most costly agricultural disease in the US - Mastitis is a public health concern as bacteria can contaminate milk and dairy products - Controlled by strict hygiene Characteristics of the Organism • S. aureus is present in many food types - Various meat products - Various fish products - Assorted cream pies - Tuna pot pies - Deli salads • Bacterial load is usually low < 100 CFU/g • Bacteria can grow to > 106 CFU / g Characteristics of the Organism • As there are so many human and animal reservoi t lli t h l l irs, controlling staphylococcal infections is challenging Characteristics of the Organism Resistance to Adverse Environmental Conditions • Unique resistance to inhibitors • Grows with high salt • Grows with low water activity of 0.86 under aerobic conditions (anaerobic 0.90) Mannitol Salt Agar - cured meats - puddings - sauces Mannitol Salt Agar