1. NURS 218 MICROBIOLOGY IN NURSING
Microbial Infections of the Nervous System and Cardiovascular and lymphatic system

2. Learning Objectives
At the end of this lecture the students will be able to:
Recognize common microbial infections involving the nervous system the cardiovascular system
Identify specific pathogens that are responsible for the development of the disease in the specific system
Outline the various signs and symptoms
Describe the treatments involved.

3. OUTLINE Microbial Infections of the cardiovascular system
Microbial Infections of the Nervous System
MENINGITIS
PURULENT MENINGITIS
CHRONIC MENINGITIS
TETANUS (CLOSTRIDIUM TETANI)
BOTULISM (CLOSTRIDIUM BOTULINUM)
POLIOMYELITIS
RABIES
ARBORAL ENCEPHALITIS
Common Pathogens of the CNS
General Treatment
Microbial Infections of the cardiovascular system
Intravascular Infections
Infectious Endocarditis
Sepsis and Septic Shock
Gas Gangrene
Bacterial Infections:Plague
Brucellosis
Lyme Disease
Viral Infection
Epstein-Barr Virus Infection
Parasitic Infection
Malaria
Chag’s Disease
Filiariasis
Schistosomiasis

4. Microbial Infections of the Nervous System

5. COMMON PATHOGENS AND ROUTES FOR CNS INFECTIONS
CNS consists of the brain and the spinal cord & infections can be caused by:
Normal bacterial flora
Pathogens acquired through ingestion
Pathogens acquired during the birthing process
Contamination of shunts
Microbial infections of the CNS are infrequent have often have serious consequences.
In preantibiotic times, there were almost fatal

6. MENINGITIS
Initial symptoms are a triad of fever, headache and a stiff neck
Often followed by nausea and vomiting
eventually progress to convulsions and coma
many who survived an attack suffer some degree of neurological damage.
It can be caused by different types of pathogen: viruses, bacteria, fungi and protozoa

7. PURULENT MENINGITIS
Infection of the meninges ( the system of membranes which envelopes the central nervous system).
Usually caused by a bacterial infection
Characterized by fever, irritability, and various degrees of neurological dysfunction

8. CHRONIC MENINGITIS
Usually caused by Mycobacterium tuberculosis, fungi, or protozoan parasites.
Characterized by fever, headache, stiff neck and back, nausea, and vomiting

9. TETANUS (CLOSTRIDIUM TETANI)
Tetanus is caused by Clostridium tetani.
Gram-positive
Anaerobic
Rod shaped
Produces a terminal spore
Toxin produced by C. tetani is neurogenic

10. BOTULISM (CLOSTRIDIUM BOTULINUM)
Etiologic agent is Clostridium botulinum.
Gram-positive
Anaerobic
Spore-forming
Rod-shaped
Found naturally in soil and sediments of ponds and lakes.

11. POLIOMYELITIS
POLIOMYELITIS: Infection which destroys cells associated with the anterior the spinal cord, and brain stem.
Causes weakness or paralysis of muscle groups
& Can cause respiratory difficulties
Characterized by asymmetrical paralysis
ACUTE POLIOMYELITIS : Inflammatory infection of the peripheral nervous system (consists of the nerves and ganglia outside of the brain and the spinal cord)
Characterized by symmetrical paralysis
Can be caused by diphtheria toxin, enteric pathogens, cytomegalovirus, and Epstein-Barr virus

12. RABIES Rabies is an acute and fatal viral CNS infection.
Can affect all mammals
Transmitted by infected secretions (usually through a bite).
Prevention is the best cure.
Treatment consists of a course of injections.
Only beneficial if administered before the onset of symptoms
Mortality for rabies is 90%.

13. ARBORAL ENCEPHALITIS
Encephalitis – caused by mosquito-borne viruses ( arboviruses)
causes subclinical to severe symptoms including rapid death
Active cases – characterized by chills, headache, and fever.
As disease progress – mental confusion and coma
Survivors suffer from permanent neurological problems

14. COMMON PATHOGENS OF THE CNS
Acute meningitis usually caused by:
H. influenzae
Neiserria meningitidis
streptococcus pneumoniae
A vaccine is available to protect against H. influenzae.
Group B streptococci and E. coli often involved in meningitis in newborns
Acquired through the birthing process

15. Most common viral causes of acute CNS infections:
Enterovirus
Herpes simplex virus
HIV
Epstein-Barr virus
Also several arthropod-borne viruses
Deep fungal mycoses Cryptococcus neoformans and Coccidioides immitis

16. GENERAL TREATMENT OF CNS INFECTIONS
Bacterial and fungal infections require prompt and aggressive treatment.
Treatment periods vary depending on the type of infection.
10 days to 12 months for uncomplicated cases
Longer if the infection is caused by M. tuberculosis
Treatment of fungal infections can last for years.
Treatment of viral infections is mostly supportive.

17. INFECTIONS OF BLOOD AND CARDIOVASCULAR SYSTEM

18. Infections in the blood easily become systemic and systemic infections can have devastating effects on the patient.
Types:
Bacteremia
Viremia
Fungemia
Parasitemia
Pathogenic organisms growing in the blood can lead to major clinical conditions:
Sepsis & Septic shock

19. Why is this Important?
Infections in the blood easily become systemic and systemic infections can have devastating effects on the patient.

20. OVERVIEW
Systemic nature of blood infections requires aggressive treatment.
Blood has access to the entire body:
Can carry pathogens from one location to another.
Presence of circulating pathogens is a natural progression of an infection:
These are quickly removed from the blood by host defenses.
In some cases pathogens in the blood reflect a serious, uncontrollable infection.

21. Depending on type of organism blood infections are classified as:
Bacteremia
Viremia
Fungemia
Parasitemia
Pathogenic organisms growing in the blood can lead to major clinical conditions:
Sepsis
Septic shock
Bacteremia and fungemia can also be caused by pathogens growing inside or outside of intravenous devices.

22. INTRAVASCULAR INFECTIONS
INTRAVASCULAR INFECTIONS-arise when pathogens enter the blood and damage the structures of cardiovascular system
Endocarditis – infection of the heart
Thrombophlebitis – infection in the veins
Endoarteritis – infection of the arteries
Most commonly caused by bacteria
Fungi are sometimes involved.
Infections of the cardiovascular are very dangerous & Can be fatal
Commonly produce shedding of organisms into the blood.

23. INFECTIOUS ENDOCARDITIS
Once referred to as bacterial endocarditis
Now known that organisms other than bacteria can cause it
Infection affects the heart valves
Can also develop on the septa of the heart and cardiac shunts.
Infectious endocarditis classified in two ways:
Acute – high fever and toxicity
Can result in death within few days or weeks
Subacute – low fever, weight loss, and night sweats
Death can take weeks to months

24. INFECTIOUS ENDOCARDITIS

25. Complications from infectious endocarditis:
Risk of congestive heart failure
Rupture of the chordae tendineae (group of tough, tendinous strands in the heart )
Perforation of the valves
Kidney damage
Blood is found in urine.

26. SEPSIS AND SEPTIC SHOCK
SEPSIS AND SEPTIC SHOCK- both result from the progression of bacteremia
Gram-positive and Gram-negative bacteria can be responsible
Fungi, protozoa, and viruses can also be the cause
Sepsis – an infection which causes a host response including: sepsis causing altered blood flow to organs causing reduced urine ; changes in mental status; Development of hypotension
Multiorgan failure and death.

27. GAS GANGRENE Gangrene caused by Clostridium perfringens.
Tissue necrosis resulting from an obstructed blood supply.
Bacteria responsible for the infection release gases.
Usually associated with deep tissue wounds.
Movement of the affected area causes snap, crackle, and popping sounds , a foul smell
Infection is accompanied by high fever, massive tissue destruction, shock, and blackened skin.
If not treated, gas gangrene is lethal.

28. BACTERIAL INFECTIONS OF THE BLOOD: PLAGUE
Vector-transmitted to humans.
Most explosively virulent bacterial infection ever known.
Spreads from lymph nodes to blood
From there can spread to the lungs
Referred to as pneumonic plague
Bacteria multiply very rapidly in lymph nodes
Produces a bubo
From bubo, bacteria spread rapidly into the blood.

29. PLAGUE: Pathogenesis

30. BRUCELLOSIS
Brucella enters the host through cuts in the skin, contact with mucous membranes, inhalation; Ingestion
Zoonotic infection which involves infection of the reproductive tract.
Transmission to humans is by:
Occupational contact
Ingesting contaminated animal products
Chronic illness in humans
Can last for weeks or months
Causes fever, night sweats, and weight loss
Cyclic pattern of symptoms – undulant fever

31. LYME DISEASE Transmitted to humans by Ixodes tick.
Caused by the spirochete Borrelia burgdorferi
Gram-negative
Requires specialized medium for growth
Involves ticks, mice, and deer
Humans are incidentally involved
Acute Lyme disease characterized by:
Fever
Migratory bull’s-eye rash
Muscular and joint pain
Often meningeal irritation
Deer are host for the final stages

32. LYME DISEASE: Pathogenesis

33. VIRAL INFECTIONS OF THE BLOOD
Viruses can be found in the blood – viremia.
Some viruses use blood cells as their hosts.
CYTOMEGALOVIRUS- is a herpes viral genus of the Herpesviruses group
ARBOVIRUSES- a group of viruses that are transmitted by arthropod vectors & infections in blood are classified as fever infections.
Dengue fever & Yellow fever: arbovirus attacks the liver and vector for both are mosquitoes.

34. EPSTEIN-BARR VIRUS INFECTION
EPSTEIN-BARR VIRUS- human herpesvirus, a cancer-causing virus of the herpes family, which includes herpes simplex virus1 and 2, and is one of the most common viruses in humans.

35. PARASITIC INFECTIONS OF THE BLOOD
There are several important and dangerous parasitic infections of the blood:
Malaria
Trypanosomiasis
Filariasis
Toxoplasmosis
Schistosomiasis

37. Malaria

39. CHAGAS’ DISEASE/ Trypanosomiasis
American form of trypanosomiasis.
Caused by the flagellate protozoan Trypanosoma cruzi.

40. FILARIASIS
Caused by thread-like filarial nematodes (roundworms) family known as "filariae
Tissue changes seen in elephantiasis are often irreversible.
Enlarging of the extremities may be ameliorated through the use of pressure bandages.
Control of the vector helps prevent infection.

41. Schistosomiasis
Schistosomiasis also known as bilharzia, bilharziosis or snail fever) is a parasitic disease caused by several species of tremotodes ("flukes")
a parasitic worm of the genus Schistosoma