Microbiology with diseases by body system;

1. Microbial cardiovascular and systemic disease

2. Cardiovascular system and septicemia
 Blood is normally axenic, it contains no microbes
 Septicemia refers to microbial infection of the blood which can
lead to septic shock
 Depending on the type of organism, blood infections are referred
to as:
 *Bacteremia (bacterial septicemia)
 Viremia
 Fungemia
 Parasitemia
Petechiae – sign of bacteremia

3.  Bacteria can release toxins from a site of infection into the blood
causing toxemia
 Exotoxins: i.e., neurotoxins (botulism/tetanus)
 Endotoxins: lipid A of LPS, which can lead to shock
 Severe form of toxemia with septic shock
 Streptococcal toxic-shock-like syndrome (TSLS)
 Streptococcus pyogenes
 From infections of skin/wound
 Staphylococcal toxic shock syndrome (TSS)
 Staphylococcus aureus
 From reproductive tract infections
Cardiovascular system and septicemia

4.  Bacterial septicemia can be associated with
 Infections of the skin/wound
 Surgical wounds
 Urinary tract infections
 Infected teeth
 Improperly sterilized kidney dialysis machines, ….
 Caused by opportunistic or nosocomial bacteria such as
 Escherichia coli, Pseudomonas aeruginosa, Neisseria meningitidis,
Haemophilus influenzae
 Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus
pyogenes
Cardiovascular system and septicemia

5.  Diagnosis of septicemia involves analysis of signs/symptoms
 Culturing bacteria from the blood
 In occult septicemia the exact bacterial cause is hidden
 Treatment involves
 Use of antimicrobial drugs
 Elimination of the initial site of infection (source of
septicemia)
 Intravenous fluid replacement/Antibodies against LPS
 Toxemia caused by Gram negative bacteria
Cardiovascular system and septicemia

6.  Blood and lymph can carry pathogens throughout the body to
cause systemic disease
 Bacterial
 Tularemia
 Plague
 Lyme disease
 Viral
 EBV (Epstein-Barr Virus)
 Cytomegalovirus
 Protozoan
 Toxoplasmosis
 Malaria
 Chaga’s disease
 Helminths
 Schistosomiasis
Microbial systemic disease

7. Bacterial systemic diseases - Tularemia
 Tularemia is a zoonotic disease caused by Francisella tularensis (Gram-
negative coccobacillus)
 Virulence (endotoxin and lipid
capsule – resists phagocytosis)
 Prevalence in animals as
intracellular parasite: from mammals
(rabbit ), to birds, fish, ticks, flies,
mosquitoes, mites
 Multiple mode of transmission
 bite of a tick
 contact with infected animal/animal
slaughter
 contaminated meat or water
 aerosols produced in the laboratory
Mortality rate: ~ 5% of untreated
patients

8. Bacterial systemic diseases - Tularemia
 Highly virulent organism
that causes
 Skin lesion (ulcer) and
swollen pus-filled lymph
nodes near the site of
infection, lymphangitis
 General symptoms may
last for months/years
 malaise, fatigue, joint
stiffness, myalgia
 Diagnosis/treatment
 Serological testing
 Antimicrobials
 Vaccine for people at risk
 Possible use of Francisella as bioterrorism weapon – nationally
notifiable disease (CDC)

9. Plague – Yersinia pestis (Enterobacteriaceae)
 Bubonic plague - bite of infected flea or direct contact with infected
animal
 Pneumonic plague - bacilli spread from the blood to the lungs or are
inhaled (airborne transmission)
 Plague has caused several pandemics
Xenopsylla
cheopis

10. Plague – Yersinia pestis
Bubo: painfully inflamed
lymph node
Darkening of dead tissues
 Plague has been called the “Black Death”
 Bubonic plague is fatal in ~50% of
cases if untreated
 Pneumonic plague is fatal in ~100%
of cases if untreated
 Urban living, rodent and flea
control, antibacterial drugs have
almost eliminated plague
 The disease is considered endemic
in states like California, Arizona,
Nevada
 Potential bioterrorism weapon:
deadly, progresses rapidly, spread
among people

11. Lyme disease (zoonosis)
 Caused by the spirochete
Borrelia burgdorferi
Gram negative
 Bull’s eye rash at the site of
infection
 Untreated patients can develop
severe arthritis

12. Lyme disease is transmitted by a deer tick (Ixodes)
 Deer tick: a 2-years life cycle

13. Lyme disease
 Increase in cases of Lyme
disease
 Diagnosis: detecting
antibodies against
Borrelia
 Antimicrobial drugs can
cure the Lyme disease
(first phase)
 Treatment of later
phases involves anti-
inflammatory drugs

14. Viral systemic diseases – Epstein Barr virus (EBV)
 HHV-4
 Implicated with several diseases, depending on the “relative vigor”
of a host’s cellular immune response

15. EBV and infectious mononucleosis
 EBV is transmitted via saliva, enters the blood and infects B cells,
which become enlarged with lobed nuclei
 Cytotoxic T cells kill infected B cells
 Signs and symptoms: fever, sore throat, fatigue,
enlarged lymph nods and spleen
 Diagnosis: detecting antibody against EBV
 Recover of most patients in few weeks without
specific therapy
 EBV can become latent in the oropharynx: life
long infection which rarely cause disease

16. Cytomegalovirus (CMV) – Herpes virus
 Most people infected with CMV are asymptomatic
 CMV remains in a latent state in various cells
 Complications in
 Immunocompromised patients
 May develop pneumonia, blindness,
 CMV mononucleosis
 Fetuses (may be teratogenic)/newborns
 ~7.5% of neonates infected with CMV
 Bodily secretions carry CMV (saliva, mucous, milk, urine, feces,
semen, vaginal secretions) – it would require a large exchange of
secretions

17. Cytomegalovirus (CMV) – herpes virus
 CMV infections is one of the most common infections in humans
 Transmission usually occurs via
 Sexual intercourse
 Prenatal infection
 Vaginal birth
 Blood transfusion
 Organ transplants
 Diagnosis/Treatment involve
 Owl’s eye appearance of enlarged cells, detection of CMV and
antibodies against CMV
 Interferons, anti CMV immunoglobulins, fomivirsen against
replication of CMV in retinal cells. There is no vaccine against
CMV

18. Protozoan diseases – Toxoplasmosis
 Toxoplasma gondii
 Nucleated cells of wild and
domesticated mammals, birds
 Immunocompromised patients can develop the disease
 Fever, inflammation of several organs, spastic paralysis,
blindness, encephalitis, and death
 Transplacental infections – (first-trimester at higher risk) can cause
spontaneous abortion, mental retardation, blindness, or microcephaly
 Healthy individuals (mostly
asymptomatic)
 Infection normally resolves
without treatment

19.  Humans become infected
when ingesting undercooked
contaminated meat
 Serological detection and
microscopic identification in
tissue samples
 Treatment with a combination
of drugs in AIDS patients,
pregnant women, newborns
Wash fruits and vegetables, eat well
cooked meat!!!
Protozoan diseases – Toxoplasmosis
 Definitive host

20. Malaria is transmitted by
Anopheles mosquito
 Plasmodium species, including
P. falciparum (blackwater
fever)/P. vivax (chronic
malaria)
 Malarial paroxysms: cycles of
fever-chills correlate with
period of erythrocyte lysis
 Anemia and jaundice
(liver/eyes)

21. Protozoan diseases - Malaria
Ring-stage - trophozoites
within red blood cells
 Microscopic examination of blood smears allows diagnosis of
malaria
 Serological tests for specific diagnosis
 Treatment and supportive
measures
 Antimalarial drugs
 Anti-fever medication
 Blood transfusions
 Alternative methods involve
 Limiting contact with mosquitos
carrying Plasmodium
 Malaria vaccines (development
and testing in progress)

22. Protozoan diseases - Malaria
 Malaria is endemic throughout the tropics and subtropics, where
Anopheles breeds
 Mosquito eradication programs eliminated the disease in
Countries like US
 Over 500 million people
are infected
 1-3 million people die
annually

23. Chagas’ disease – American trypanosomiasis
 Caused by Trypanosoma cruzi
 Transmitted with the feces of the bloodsucking “kissing bug”
 Major reservoirs: opossum and armadillos though most mammals,
including humans, can carry the parasite
 ~ 1% of infected humans
develop early stages (general
symptoms)
 Intermediate asymptomatic
(chronic) stage for up to ~ 20
years
 Heart failure during final
symptomatic stage
 Clusters of parasites in the
heart muscle tissue
Trypomastigotes (infective) circulating
in the blood are ingested by the kissing
bug

24. Chagas’ disease – American trypanosomiasis
 The disease is endemic in Central and South America
 Affects 8-15 million people
 Thousands die each
year, including children
 Early stages can be treated
but not late stages
 No vaccine exists for
Chagas’s disease
 Prevention involves measures that protect against bugs: mud
replaced with concrete/brick, insecticides …..

25. Schistosomiasis is caused by blood flukes
 Genus
Schistosoma
 The larval stage
cercaria burrows
into the skin
 Feeding on blood,
matures, mates, and
releases eggs
 Eggs lodge in
tissues causing
damage to several
organs

26.  Treatment/control: drugs that kill the
worm in the body, sewage treatment,
and snail suppression
Egg of Schistosoma mansoni
 Diagnosis: identification of eggs -
shape of the egg and location of the
spines - in stool or urine samples
 WHO (World Health Organization) estimates that over 250 million
people are infected worldwide – Asia, Africa, South America
Schistosomiasis is caused by blood flukes
Scarlike tissue surrounds the egg