Microbial Infections Respiratory and Digestive System

1. NURS 218 MICROBIOLOGY IN NURSING Microbial Infections Respiratory and Digestive System

2. Learning Outcomes After 2 hours of evocative lecture discussion, the students will be able to : • Review the structure and function of the respiratory and digestive system • Classify the microbial infections of the respiratory and digestive system between bacterial and viral causes • Identify the symptoms of each diseases. • Describes methods of transmission and treatment

3. OUTLINE • Overview of the Structure and Function of the Respiratory System • MICROBIAL DISEASES OF THE UPPER RESPIRATORY SYSTEM • Bacterial Disease of the Upper Respiratory System • Related Terminologies • Streptococcal Pharyngitis ( Strep Throat) • Scarlet Fever • Diphtheria • Otitis Media: • Viral Diseases of the Upper Respiratory System • Common Cold Microbial Disease of the Lower Respiratory System • Bacterial Diseases: • Pertussis (Whooping Cough) • Tuberculosis • Bacterial Pneumonias • Viral Diseases of the Lower Respiratory System

4. Microbial Infections of the Digestive System • Overview of the structures • Normal Microbiota of the Digestive System • Bacterial Disease of the Mouth • Dental Carries (Tooth Decay) • Periodontal Diseases • Bacterial disease of the Lower Digestive System • Staphylococcal Food Poisoning ( Staphylococcal Enterotoxicosis) • Typhoid Fever • Helicobacter Peptic Ulcer Disease • Peptic Ulcers • Bacterial Gastroenteritis • Viral Diseases of the Digestive System • Mumps • Hepatitis • Viral Gastroenteritis • Protozoan Diseases of the Digestive System • Amoebic Dysentery (Amoebiasis) • Giardiasis • Helminthic Diseases of the digestive System • Tapeworms • Pinworm Infestations

5. Microbial Infections of the Respiratory System

6. Overview of the Structure and Function of the Respiratory System The respiratory system is composed of two divisions: Upper Respiratory System consisting of: • Nose • Pharynx • and structures associated with them Lower Respiratory System consisting of: • Larynx • Trachea • Bronchial tubes and • Alveoli

7. MICROBIAL DISEASES OF THE UPPER RESPIRATORY SYSTEM • Related Terminologies: Pharyngitis • inflammation of the mucus membranes of the throat, or sore throat Laryngitis • infection of the larynx which affects the ability to speak Tonsillitis • inflammation of the tonsils Sinusitis • infection of a sinus involving heavy nasal discharges of mucus

8. Bacterial Disease of the Upper Respiratory System Streptococcal Pharyngitis ( Strep Throat ) • Caused by (GAS) group A streptococci • Pathogenicity is enhanced by resistance to phagocytosis • Also able to produce enzymes like: • streptokinase – lyse fibrin clots • Streptolysins – cytotoxic to tissue cells, red blood cells and protective leukocytes • Symptoms: inflamed mucous membranes of the throat • Treatment: penicillin

9. Scarlet Fever • Caused by erythrogenic toxin-producing strains of Streptococcus pyogenes • Symptoms: streptococcal exotoxin causes reddening of skin and tongue and peeling of affected skin • has been associated with streptococcal pharyngitis but might be accompanied with a streptococcal skin infection • Treatment: Penicillin

10. Diphtheria • Caused Corynebacterium diphtheriea • Symptoms: membranes forms in throat, cutaneous form also occurs • Treatment: Penicillin and antitoxin • Prevention: DtaP vaccine Otitis Media: • Complication of the common cold or of any infection of the nose or throat • also called infection of the middle ear or earache • Caused by: several agents especially Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenza • Symptoms: accumulation of pus in the middle ear builds up painful pressure on eardrum • Treatment: Broad-spectrum antibiotics • Prevention: Pneumococcal vaccine

11. Viral Diseases of the Upper Respiratory System Common Cold • About 50% are caused by rhinoviruses, 15-20% caused by coronavirus, 10% from other several viruses. • Symptoms: familiar symptoms of coughing, sneezing, runny nose • Treatment: supportive

12. Microbial Disease of the Lower Respiratory System ( Bacterial ) Pertussis (Whooping Cough) • Cause by bacterium Bordetella pertussis which is a small, obligately aerobic, gram-negative coccobacillus. • pertussis toxins that enters into the bloodstream is associated with systemic symptoms of the disease. • Catarrhal stage (initial stage): resembles a common cold • Paroxysmal stage: characterized by prolonged sieges of coughing; episodes occurring several times a day for 1-6 weeks • Convalescence stage: may last for months • irreversible damage to the brain occurs in infants who are less capable of coping with the effort of coughing to maintain an airway. • Prevention: DTP vaccine, Tdap for adolescents and adults • Treatment: antibiotics, most common erythromycin or other macrolides

13. Tuberculosis • caused by Mycobacterium tuberculosis, a slender rod and obligate anearobe. • Poverty and poor socioeconomic conditions are breeding grounds for tuberculosis. • Early detection is vital • Initial symptoms are similar to those seen in other respiratory infections – it is important to look for: • Fever • Fatigue • Weight loss • Chest pain • Shortness of breath • Congestion with coughing

14. Two basic types of tuberculosis • Primary • Follows initial exposure to the pathogen • Secondary • Can occur years later • Treatment • Usually a triple therapy containing: • Isoniazid (INH) • Pyrazinamide (PZA) • Rifampicin (RFP) • All three are taken once a day for two months. • INH and RFP are taken for nine more months. • If the strain is drug-resistant, initial treatment includes ethambutol. • Compliance with the drug therapy is very important. • Compliance can be difficult because of side effects. • The drugs are very toxic. • Most serious is liver toxicity.

15. Bacterial Pneumonias • Applied to many pulmonary infections, most of which are caused by bacteria. • Typical Pneumonia – caused by streptococcus pneumoniae • Atypical Pneumonia – caused by other microorganisms including fungi, protozoa, viruses and other bacteria • Common Bacterial Pneumonia: • Pneumococcal pneumonia • caused by streptococcus pneumoniae • Symptoms: infected alveoli of lung fill with fluids with oxygen uptake • Reservoir: humans • treatment: penicillin, fluoroquinolones • Prevention: pneumococcal vaccine

16. Viral Diseases of the Lower Respiratory System • Incidence varies inversely with age. • Greatest in young children • Majority of acute viral infections are in the lower respiratory tract and caused by: • Influenza virus. • Respiratory syncytial virus. • Common characteristics of infection are: • Short incubation period of 1 to 4 days. • Transmission from person to person. • Transmission can be direct or indirect. • Direct – through droplets • Indirect – through hand transfer of contaminated secretions

17. Microbial Infections of the Digestive System

18. Overview of the structures • Digestive system structures divided into two groups • Gastrointestinal tract (GI tract) • The pathway from the mouth to the anus • Accessory digestive organs • Organs involved in grinding food or providing digestive secretions • The Gastrointestinal Tract • Digests food, absorbs nutrients and water into the blood, and eliminates waste • Components of the gastrointestinal tract • Mouth • Esophagus • Stomach • Small intestine • Large intestine (colon) • Rectum and anus

19. The Accessory Digestive Organs • Tongue and teeth • Salivary glands • Liver • Gallbladder • Pancreas

20. Normal Microbiota of the Digestive System • There are large numbers of bacteria that colonize the mouth. • The stomach and small intestine have few resident microorganisms. • Bacteria in the large intestine assist in degrading food and synthesizing vitamins • About 40% of fecal mass is microbial cells. • Esophagus, Stomach, Duodenum • These regions are almost free of microbes • Peristalsis and rapid transport of food helps prevent microbial colonization • Tongue and teeth • Viridans streptococci are most prevalent in this region • Lower small intestine and colon • Microbiota here are microbial antagonists • Mucous membrane prevents microbes entering the bloodstream

21. Bacterial Disease of the Mouth Dental Carries ( Tooth Decay) • Begins when tooth enamel and dentin are eroded and the pulp is exposed to bacterial infection. • Bacteria adhere to the teeth by the stick dextran, forming dental plaque • At the site of the plaque, the acid that is produced destroys the enamel. • This makes the gram-positive rods and filamentous bacteria to penetrate into the dentin and pulp. • Carries can be prevented by restricting ingestion of sucrose and by the physical removal of plaque.

22. Periodontal Diseases • Cementum and gingivitis – caused by streptococci, actinomycetes, and anaerobic gram-negative bacteria • Chronic gum disease (periodontitis) causes bone destruction and tooth loss • Periodontitis – occurs due to inflammatory response to a variety of bacteria growing on the gums • Often caused by Prevotella intermedia

23. Bacterial disease of the Lower Digestive System Staphyloccocal Food Poisoning ( Staphylococcal Enterotoxicosis) • Caused by the ingestion of an enterotoxin produced in improperly stored foods. • S. Aureus is inoculated into foods during preparation and the bacteria grow and produce enterotoxin in food stored at room temperature. • Boiling for 30 mins is not sufficient to denature the entoxin.

24. Typhoid Fever • Caused by salmonella typhi • Transmitted by contact with human feces • Fever and malaise occur after a 2-week incubation period. Symptoms may last 2-3 weeks. • S. typhi is harbored in the gallbladder or carriers. • Treatment: quinolones and cephalosphorins; vaccines are available for high-risk people. Helicobacter Peptic Ulcer Disease • Helicobacter pylori produces ammonia • this neutralizes stomach acid • The bacteria colonize the stomach mucosa and cause peptic ulcer disease.

25. Peptic Ulcers • Epidemiology • Fecal-oral transmission is likely • Stress may worsen ulcer symptoms • Diagnosis, treatment, and prevention • Diagnosis based on X-ray exam to identify ulcers and presence of H. pylori in clinical specimens • Treat with antimicrobials and drugs that inhibit stomach acid • Prevent by avoidance of fecal-oral transmission

26. Bacterial Gastroenteritis • Inflammation of stomach or intestines caused by bacteria • Associated with contaminated food or water and poor living conditions • General features • Similar manifestations despite different causative agents • Nausea, vomiting, diarrhea, abdominal pain, and cramps • Dysentery produces loose, frequent stool containing mucus and blood

27. Viral Diseases of the Digestive System Mumps • Mumps virus enters and exits the body through the respiratory tract • 16-18 days after exposure, inflammation of the parotid glands occurs with fever, and pain during swallowing • 4-7 days later, orchitis may occur • After onset of the symptoms, the virus is found in the blood, saliva, and urine • A measles, mumps, rubella (MMR) vaccine is available as prevention

28. Hepatitis • Known as inflammation of the liver • Symptoms include loss of appetite, malaise, fever and jaundice. • Viral causes: hepatitis viruses, Epstein-Barr virus (EBV) and cytomegalovirus (CMV). • Hepatitis A • caused by hepatitis A • HAV is ingested in contaminated food or water, grows in the cells of the intestinal mucosa and spreads to the liver, kidneys, and spleen in the blood • The virus is eliminated with feces • Incubation period is 2-6 weeks; period of disease is 2-21 days, recovery is complete in 4-6 weeks. • A vaccine is available; passive immunization can provide temporary protection

29. Hepatitis B • cause by Hepatitis B virus (HBV), frequently serious • Transmitted by blood transfusions, contaminated syringes, saliva, sweat, breast milk and semen • Before blood is being used for transfusions, it is being tested for HBsAG. • Average incubation period – 3 months; recovery usually complete, but some patients develop a chronic infection or become carriers • A vaccine is available against HBsAg. • Hepatitis C • cause by Hepatitis C Virus (HCV) transmitted via blood. • Incubation period is 2-22 weeks; usually mild, but some patients develop chronic hepatitis • Blood is tested for HCV antibodies before being used in transfusions.

30. Hepatitis D (Delta Hepatitis) • Caused by Hepatitis D virus (HDV) which has a circular strand of RNA and uses HBsAg as a coat. Hepatitis E • Caused by Hepatitis E virus (HEV) • Spreads by the fecal-oral route

31. Viral Gastroenteritis • Most often caused by a rotavirus or norovirus • incubation period is 2-3 days; • Diarrhea lasts up to 1 week. • Signs and symptoms • Similar to bacterial gastroenteritis • Pathogens and pathogenesis • Caused by noroviruses and rotaviruses • Epidemiology • More cases occur in winter • Diagnosis, treatment, and prevention • Treatment is based on fluid and electrolyte replacement • Vaccine for rotavirus exists

32. Protozoan Diseases of the Digestive System Amoebic Dysentery (Amoebiasis) • Caused by Entamoeba Histolytica growing in the large intestine. • Amoeba feeds on red blood cells and GI tract tissues. • Severe infections results in abscesses. • Signs and symptoms • Luminal amebiasis is asymptomatic • Invasive amebic dysentery causes severe diarrhea, colitis, appendicitis • Invasive extraintestinal amebiasis causes necrotic lesions in various organs

33. Giardiasis • Signs and symptoms • Often asymptomatic • Diarrhea and associated symptoms can last up to four weeks • Pathogen and pathogenesis • Caused by Giardia intestinalis • G. intestinalis interferes with intestinal absorption, causing flatus • Epidemiology • Infection results from ingesting cysts in contaminated water • Hikers and campers are at particular risk • Diagnosis, treatment, and prevention • Diagnosed by microscopic observation of Giardia in stool • Treat with metronidazole (adults) or furazolidone (children)

34. Helminthic Diseases of the digestive System Tapeworms • Contracted by the consumption of undercooked beef, pork, or fish containing encysted larvae. • The scolex attaches to the intestinal mucosa of humans (the definitive host) and matures into an adult tapeworm • Eggs are shed in the feces and must be ingested by an intermediate host • Adult tapeworms can be undiagnosed in a human. • Neurocysticerosis in human occurs when the pork tapeworm larvae encyst in humans.

35. Pinworm Infestations • Pinworms are nematodes • Long, thin, unsegmented, cylindrical helminth • Signs and symptoms • Perianal itching, irritability, decreased appetite • One-third of cases are asymptomatic • Pathogen and infestation • Caused by Enterobiusvermicularis • Females deposit eggs in the perianal region at night • Eggs can be dislodged and spread the disease • Epidemiology • Infections commonly occur in children • Enterobiusis the most common parasitic worm in the U.S. • Diagnosis, treatment, and prevention • Diagnosis based on identification of eggs or adult pinworms • Treatment with anti-helminthic drugs • Prevention requires strict personal hygiene