1. Bacteremia, Septicemia and Sepsis & Systemic Fungal Infections
Dr. Soha El-Hady
Prof. of Medical Microbiology & Immunology
Group A & B Wednesday 23/10/2019

2. Intended Learning Objectives (ILOs)
By the end of this lecture the student will be able to:
Define septicemia, bacteremia and systemic fungal infections.
List the commonest causative agents of septicemia and systemic fungal infections.
Compare between Gram-negative sepsis and Gram-positive sepsis.
Describe the pathogenesis of septicemia and primary systemic fungal infections.
Recognize clinical manifestations of septicemia and systemic fungal infections.
Outline the laboratory diagnostic approach of septicemia and systemic fungal infections.
Prof. Soha El-Hady

3. Bacteremia and Septicemia are closely related.
They are two separate conditions.
Prof. Soha El-Hady

4. Bacteremia
It is the presence of bacteria inside an individual’s blood.
In some situations, bacteremia doesn’t cause any symptom
For example, there are likely bacteria released locally into the bloodstream each time we brush our teeth.
Prof. Soha El-Hady

5. Or it may be due to severe infection and invasion of blood stream.
It may be part of natural history of a disease (part of pathogenesis) like what occurs in meningitis and typhoid fever
Or it may be due to severe infection and invasion of blood stream.
Prof. Soha El-Hady

6. The simple presence of bacteria in the blood is known as Bacteremia.
Bacteremia may be transient where small quantities of bacteria are in the blood or it can be sustained, where the bacteria persist and multiply in the bloodstream causing illness i.e. Septicemia
When it is associated with clinical manifestations due to organ dysfunction (manifested by a certain score) it is referred as sepsis.
Prof. Soha El-Hady

7. Prof. Soha El-Hady

8. Sepsis
Bacteremia
Prof. Soha El-Hady

9. (Release of bacterial toxins into the blood )
Toxemia
Toxemia:
When bacteria remain fixed at a site of infection but release toxins into the blood.
Toxemia is exotoxin
(Release of bacterial toxins into the blood )
Ex: diphtheria Release of bacterial toxins into the blood .
Prof. Soha El-Hady

10. Septicemia Septicemia:
An acute illness that is associated with the presence and persistence of pathogenic microorganisms or their toxins (endotoxins) in the blood
.it trigger Sepsis
Sepsis: life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis can progress to septic shock (if not managed early and properly).
Prof. Soha El-Hady

11. Prof. Soha El-Hady

12. Immunocompetent individuals rarely have septicaemia
Immunocompetent individuals rarely have septicaemia. Bacterial infections self-limited in these people
People with suppressed immune systems due to alcoholism , other drug abuse , malnutrition, stress, or HIV infection cannot effectively fight bacterial infection
Prof. Soha El-Hady

13. Septicemia, Bacteremia, and Toxemia
Bacteria in blood that is often harmless
Septicemia
microbial infection of the blood that produces illness
Toxemia
Release of bacterial toxins into the blood
Prof. Soha El-Hady

14. Prof. Soha El-Hady

15. Bacteremia Septicemia
S.N .
Bacteremia
Septicemia 1.
Bacteremia is the simple presence of bacteria in the blood.
Septicemia is the presence and multiplication of bacteria in the blood. 2.
Bacteremia is not as dangerous as Septicemia.
Septicemia is a potentially life-threatening infection. 3.
Less amount of bacteria are present in blood.
Large amounts of bacteria are present in the blood.
Prof. Soha El-Hady

16. Toxins are not produced. Toxins may be produced by bacteria.4.
This may occur through a wound or infection, or through a surgical procedure or injection.
It can arise from infections throughout the body, including infections in the lungs, abdomen, and urinary tract. 5.
Toxins are not produced.
Toxins may be produced by bacteria.
Prof. Soha El-Hady

17. Bacteremia usually causes no symptoms or it may produce mild fever. 6.
Bacteremia usually causes no symptoms or it may produce mild fever.
It shows symptoms like chills, fever, prostration, very fast respiration and/or heart rate. 7.
It can resolve without treatment.
Untreated septicemia can quickly progress to sepsis. 8.
Rapidly removed from the bloodstream by the immune system.
Antibiotics will be used to treat the bacterial infection that is causing septicemia.
Prof. Soha El-Hady

18. Septicemia Causative organisms:
Gram-positive cocci: Staphylococci (thought to cause more than 50% of cases of sepsis), Streptococcus pyogenes and Streptococcus pneumoniae.
Gram-negative cocci: Neisseria meningitides.
Gram-positive bacilli: Clostridium causing gas gangrene, bacillus anthracis.
Gram-negative bacilli: as Escherichia coli, Salmonella spp., Pseudomonas aeruginosa, Klebsiellaspecies, Yersiniapestis and Bacteroides.
Fungi: Candida spp.
Prof. Soha El-Hady

19. Pathogenesis
Direct inoculation of bacteria into the blood during medical procedures
e.g. Prolonged peripheral and central inserted intravascular devices.
Through small abrasions in the respiratory or digestive tracts
Surgical wounds, Infected teeth and Urinary tract infections
Prof. Soha El-Hady

20. Gram-negative Sepsis or endotoxic shock:
is most likely to be caused by gram-negative bacteria as the cell walls of many Gram-negative bacteria contain endotoxins that are released upon lysis of the cell which develops septicemia.
Gram-Positive Sepsis:
One of the most common causes of sepsis which develops as a severe form of toxemia.
Both staphylococci and streptococci produce potent exotoxins that cause toxic shock syndrome.
Prof. Soha El-Hady

21. Gram-negative bacteria more often produce severe septicaemia.
Due to release of Endotoxin as the bacteria die activates various defensive reactions by the body
Prof. Soha El-Hady

22. A severe form of toxemia with septic shock in:
Staphylococcus Toxic shock syndrome:
It can occur in localized or wound infection caused by certain toxin producing strains of S. aureus.
It is caused by S.aureus strains producing TSST which acts as superantigen.
Toxic shock syndrome is characterized by hypotension ending in shock with multisystem organ failure.
Streptococcal toxic shock like syndrome
Prof. Soha El-Hady

23. Clinical manifestations:
Fever, chills, nausea, vomiting, diarrhea, malaise, shortness of breath, change in mental status, confusion and anxiety
When sepsis results in a drop-in blood pressure (shock) and dysfunction of at least one organ, it is considered to be septic shock.
Prof. Soha El-Hady

24. Prof. Soha El-Hady

25. “Laboratory diagnosis”
Prof. Soha El-Hady

26. Isolation of causative organism from blood using blood culture
Laboratory Diagnosis
Isolation of causative organism from
blood using blood culture
Prof. Soha El-Hady

27. Treatment Prolonged course of tetracycline and streptomycin.
Prevention:
Pasteurization of Milk.
Health education of farmers , slauterhouse workers.
Active immunization of animals with a virulent strains.
Prof. Soha El-Hady

28. Treatment
Treatment with antibiotics and IV fluids should start immediately (Before the Lab. results are out).
In case of toxic shock syndrome, in addition to antibiotics, therapy should include an antibiotic inhibitor of protein synthesis (e.g. clindamycin) to inhibit toxin synthesis.
Prof. Soha El-Hady

29. Systemic Mycoses
Systemic fungal infections are deep seated fungal infections that can be primary or opportunistic.
Prof. Soha El-Hady

30. Primary Systemic Mycoses
There are four dimorphic fungi causing primary systemic mycoses:
Histoplasma capsulatum (non capsulated).
Coccidioides immitis.
Blastomyses dermatitdis.
Paracoccidioides brasillensis.
Each one is geographically restricted to specific area of endemicity but Histoplasma capsulatum is global.
Prof. Soha El-Hady

31. Pathogenesis:
Infection of primary systemic mycoses is initiated in lungs following inhalation of conidia (No person to person transmission).
Following inhalation, arthroconidia changes into tissue form.
The host defenses are initiated by alveolar macrophages with initiation of granuloma formation.
Prof. Soha El-Hady

32. Healing is spontaneous with calcification of granuloma but some viable organisms may remain in granulomas.
Severe disseminated infections develop in minority of infected individuals particularly infants and immunocompromised.
Prof. Soha El-Hady

33. Clinical Picture Clinical presentation: Asymptomatic.
Flu like illness with fever, chills, myalgia, headache and non-productive cough.
Chronic pulmnoary disease.
Disseminated infection with high mortality rate in immunosuppressed patients (particularly in skin, brain and bones).
Prof. Soha El-Hady

34. Treatment Disseminated disease: IV amphotericin B
Prolonged course of tetracycline and streptomycin.
Prevention:
Pasteurization of Milk.
Health education of farmers , slauterhouse workers.
Active immunization of animals with a virulent strains.
Disseminated disease: IV amphotericin B
Prof. Soha El-Hady

35. The four endemic mycoses
Histoplasma
Capsulatum
Coccidioides immitis
(Valley fever)
Blastomyces dermatidis
Paracoccidioidis
brasillensis
Ecology
Alkaline soil
Soil enriched with bird or bat feces
Alkaline desert sand
Unknown, might be associated with rotting wood
unknown
Geographical distribution
Global
Endemic in some areas of united states and Central Africa
Some areas in United States and South America
Some areas in the United States
Some areas in Central and South America
Prof. Soha El-Hady

36. Specific points in clinical picture
Tissue form
Oval yeast, intracellular in macrophages as it interferes with phagocytic killing
spherules that contain endospores.
The spherules have thick double refractile wall
Thick walled yeasts with broad based single buds
Large multiply budding yeast
Specific points in clinical picture
Histoplasma is phagocytosed by alveolar macrophages and neutrophils which circulate in blood so splenomegaly is often. Thick blood smears and blood culture is extremely useful in diagnosis
A number of extrapulmonary
Sites Might be involved by hematogenous
spread. Most frequent involved organs are skin, bones and joints
Less likely to be resolved than histoplasma and coccidioides
Prof. Soha El-Hady

37. Opportunistic Mycoses
They are caused by endogenous or exogenous organisms of low virulence in debilitated compromised hosts.
The severity of infection is directly proportional to the degree of immunosuppression.
Prof. Soha El-Hady

38. Causative organisms: Candida spp. Cryptococcus neoformans.
Aspergillus spp.
Mucor, Rhizopus, Absidia.
Pneumocystis jirovocii.
Prof. Soha El-Hady

39. Candida species Clinical picture: Bloodstream infections:
Occurs in patients with indwelling catheter.
Infections are manifested by fever.
Deposition and growth of candida may occur at any site in the body in patients with compromised innate phagocytic defenses especially the kidney, skin (macro-nodular lesions) eyes, meninges and heart.
Candidal endocarditis is frequently associated with deposition and growth of yeast and pseudo-hyphae on prosthetic heart valves.
Broncho-pulmonary infections.
Esophagitis and gastritis.
Prof. Soha El-Hady

40. Laboratory Diagnosis G
Isolation of Candida from blood using blood culture.
Candida antigen assay in blood.
Prof. Soha El-Hady

41. Treatment IV amphotericin B.
Prolonged course of tetracycline and streptomycin.
Prevention:
Pasteurization of Milk.
Health education of farmers , slauterhouse workers.
Active immunization of animals with a virulent strains.
Prof. Soha El-Hady

42. Summary
Prof. Soha El-Hady

43. Bacteremia is the simple presence of bacteria in the blood.
Bacteremia may be transient where small quantities of bacteria are in the blood or it can be sustained, where the bacteria persist and multiply in the bloodstream causing illness i.e. Septicemia
When it is associated with clinical manifestations due to organ dysfunction it is referred as sepsis.
Prof. Soha El-Hady

44. (Release of bacterial toxins into the blood )
Toxemia: When bacteria remain fixed at a site of infection but release toxins into the blood.
Toxemia is exotoxin
(Release of bacterial toxins into the blood )
Septicemia: is An acute illness that is associated with the presence and persistence of pathogenic microorganisms or their toxins (endotoxins) in the blood .It trigger Sepsis
Sepsis: life-threatening organ dysfunction. Sepsis can progress to septic shock.
Group A Tuseday 19/12/2017 & Group B Wednesday 20/12/2017

45. Group A Tuseday 19/12/2017 & Group B Wednesday 20/12/2017
Bacteremia
Bacteria in blood that is often harmless
Septicemia
microbial infection of the blood that produces illness
Toxemia
Release of bacterial toxins into the blood
Group A Tuseday 19/12/2017 & Group B Wednesday 20/12/2017

46. Group A Tuseday 19/12/2017 & Group B Wednesday 20/12/2017
Septicemia :is most likely to be caused by gram-negative bacteria due to release of endotoxins upon lysis of the cell.
Toxemia: is most likely to be caused by gram-positive bacteria due to release of exotoxins.
Group A Tuseday 19/12/2017 & Group B Wednesday 20/12/2017

47. Which one of the following is the main virulence factor responsible for sepsis (septic shock) caused by Gram negative bacteria?
Bacterial endotoxin
Lecithinase (alpha toxin)
Polypeptide capsule
Polysaccharide capsule
Toxic shock syndrome toxin

48. On line evaluation
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50. Thank You
Prof. Soha El-Hady