Microbiology Fundamentals A Clinical Approach Chapter 18 and 19

These carry blood to and from all regions of the body

blood vessels

Circulatory is considered what type of system? open or closed?

Closed

What blood vessel carries oxygenated blood away from the heart?

Arteries

What blood vessel carries deoxygenated blood back to the heart?

Veins

These are the smallest blood vessels that connect arteriols to venules and have only one layer of endothelium

capillaries

This system is closely related to cardiovasclar system, major source of immune cells and fluids. Has Lymph nodes at body sites like groin, neck, armpit, intestines, and spleen

Lymphatic System

What is bacteria growing and flourishing in the blood?

Septicemia (sepsis)

Cascading immune responses to septicemia resulting in decreased blood pressure

Septic shock

Which of the following terms refers to bacteria flourishing and growing in the bloodstream?

C. Septicemia

True or False: The cardiovascular and lymphatic systems, being "closed" systems, are always completely sterile.

False

•one of the greatest afflictions throughout human history:

-Dominant protozoan disease

•Threatens 40% of the world's population every year:

Malaria

•Signs and Symptoms:

-10-day incubation period, first symptoms are:

•Malaise, fatigue, vague aches, and nausea with or without diarrhea, chills, fever, and sweating

•Symptoms occur at 48- or 72-hour intervals, as the result of synchronous red-blood-cell rupture

Malaria

persistent fever, cough, and weakness for weeks without relief (specific type of Malaria)

Falciparum Malaria

What is the casuative agent for Malaria?

Plasmodium

What are two phases malarial parasite is divided into?

Asexual phase and Sexual phase

•Pathogenesis and Virulence Factors:

-Invasion of merozoites into RBCs leads to the release of fever-inducing chemicals into the bloodstream. Chills and fevers often occur in a cyclic pattern.

-Plasmodium also metabolizes glucose at a very high rate, leading to hypoglycemia in the human host.

-Damage to RBCs results in anemia.

-Accumulation of malarial products in the liver and the immune stimulation in the spleen can lead to enlargement of these organs.

Malaria

How is Malaria transmitted?

Anopheles mosquito

How is malaria prevented?

Long-term mosquito abatement and human chemoprophylaxis.

How is malaria treated?

Quinine

A spectrum of clinical signs and symptoms is associated with __

• The levels of virus in the blood

• The levels of T cells in the blood

Initial symptoms:

• Fatigue, diarrhea, weight loss, and neurological changes

• Opportunistic infections or neoplasms (cancer)

HIV

Causative agent for HIV

Retrovirus in the genus Lentivirus

What does the causative agent for HIV contain?

Reverse Transcriptase

•Pathogenesis and Virulence Factors:

-Viral life cycle:

•__________ enters a mucous membrane or the skin and travels to dendritic cells beneath the epithelium. Virus grows inside the dendritic cell and is shed without killing the cell.

•The virus is amplified by macrophages in the skin, lymph organs, bone marrow, and blood. It infects and destroys helper T4 and CD4 lymphocytes, monocytes, macrophages, and B lymphocytes.

•The virus docks to host cell surface receptors and induces cell fusion, creating syncytia.

HIV

How is HIV and Aids transmitted?

• Sexual intercourse or transfer of blood or blood products

• Babies can be infected before or during birth, or through breastfeeding.

Mode of transmission:

• Similar to the hepatitis B virus, except HIV does not survive long outside the host and is more sensitive to disinfectants.

• Virus is not transmitted through saliva.

How is HIV infection and AIDS diagnosed?

Antibodies

WHat are the 3 criteria for a diagnosis with aids?

CD$ cells below 200

CD$ cells account for fewer than 14 percent

One or more AIDS defining illnesses

How is HIV prevented?

-Avoidance of sexual contact with infected persons

•Abstaining from sex is an obvious prevention method.

•Sexually active individuals should consider that every partner is infected unless proven otherwise.

•Barrier protection should be used when having sex with anyone whose HIV status is not known with certainty to be negative.

-Avoiding intravenous drugs

-Pre-exposure prophylaxis

•Inflammation of the endocardium, or inner lining of the heart; this most often refers to an infection of the valves of the heart, the mitral valve, or the aortic valve

•Two variations of endocarditis, each with distinct groups of causative agents:

-Acute

-Subacute

Endocarditis

-Similar for both acute and subacute _________

-Fever, fatigue, joint pain, edema of feet, legs, and abdomen, weakness, anemia, abnormal heartbeat, and sometimes symptoms similar to those of a myocardial infarction:

•Symptoms of subacute endocarditis develop more slowly and are less pronounced than those of the acute disease.

•Abdominal or side pain is sometimes reported.

•Patient may look very ill and have petechiae over the upper half of the body and under the fingernails.

Endocarditis

•Most often the result of an overwhelming bloodstream challenge with bacteria:

-Certain bacteria have the ability to colonize normal heart valves. "Vegetations," or accumulations of bacteria on the valves, hamper their function. This can lead directly to cardiac malfunction and death.

-Alternatively, pieces of bacterial vegetation can break off and create emboli, or blockages in vital organs.

-Bacterial colonies prove a constant source of blood-borne bacteria.

Acute Endocarditis

What are the 4 bacteria that causes endocarditis?

Staphlococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Neisseria gonorrhoeae

How is acute endocarditis transmitted?

Parenteral

What is the causative agent for subacute endocarditis

Streptococcus sangulis, S. oralis, or S. mutans

How is subacute Endocarditis transmitted?

-Minor disruptions of skin or mucous membranes introduce bacteria into the bloodstream and lead to colonization:

•Rigorous tooth brushing

•Dental procedures

•Minor cuts and lacerations

-Bacteria are not transmitted from other people or the environment.

How is subacute endocarditis prevented?

Prophylactic antibiotic therapy

•Bacterium is injected by the bite of a flea, enters the lymph, and is filtered by a local lymph node.

•Infection causes inflammation and necrosis of the node, resulting in a swollen lesion called a bubo, usually in the groin or axilla.

•Incubation period lasts 2 - 8 days, ending with chills fever, headache, nausea weakness, and tenderness of the bubo.

•Mortality rates are greater than 15%.

Bubonic Plague

•Pneumonic and bubonic plague often progress to massive bacterial growth in the blood.

•Presence of bacteria in the blood results in disseminated intravascular coagulation, subcutaneous hemorrhage, and purpura, which may degenerate into necrosis and gangrene.

•Mortality rates, once the disease reaches this point, are 30 to 50%, with treatment and 100% without treatment.

•Because of the visible darkening of the skin, the plague has often been called "the black death."

Septicemia Plaque

What is the casuative agent for plague?

Yersinia Pestis

How is the plague transmitted?

Fleas

-Nonfatal, but often evolves into a slowly progressive syndrome that mimics neuromuscular and rheumatoid arthritis.

-Erythema migrans:

•An early symptom in 70% of cases

•A rash at the site of a tick bite looks like a bull's-eye with a raised erythematous ring that gradually spreads outward with a pale central region.

-Other early symptoms are fever, headache, stiff neck, and dizziness.

-If not treated or treated too late, the disease can advance to the second stage:

•Cardiac and neurological symptoms, such as facial palsy can develop.

-Third stage:

•Crippling arthritis

•Some people acquire chronic neurological complications that are severely disabling.

Lyme Disease

What is the causative agent for lyme disease?

Borrelia burgdorferi

•Pathogenesis and Virulence Factors:

-The bacterium is a master of immune evasion. It changes its surface antigens while it is in the tick and again after it has been transmitted to the mammalian host.

-Provokes a strong humoral immune response:

•Response is mainly ineffective because of the bacterium's ability to switch its antigens. It is possible that the immune response contributes to the pathology of the infection.

Lyme disease

How is lyme disease treated?

3-4 weeks of treatment with doxycycline and amoxicillin

-Often called "mono" or "the kissing disease"

-Can be caused by a number of bacteria or viruses

-Vast majority are caused by the Epstein-Barr virus (EBV), a member of the herpesvirus family

Infectious Mononucleosis

Signs and Symptoms:

After a 30 - 50 day incubation period:

• Sore throat

• High fever

• Cervical lymphadenopathy

• Gray-white exudate in the throat

• Skin rash

• Enlarged spleen and liver

• A notable sign is sudden leukocytosis, consisting initially of infected B cells and later T cells.

• Fatigue is a hallmark of the disease. Strong, cell-mediated response is decisive in controlling the disease.

Mono

How is mono transmitted?

Direct oral contact and contamination with saliva

What are the 6 areas of Upper Respiratory Tract?

Mouth, Nose, Nasal Cavity, Sinuses, Throat or pharyn, and epiglottis

What are the 4 areas of the lower respiratory tract?

Trachea, Bronchi, Bronchioles, and Alveoil

What are the 5 second and third line defenses?

• Complement

• Antimicrobial peptides

• Chemocytokines

• Macrophages

• Secretory IgA

Signs and Symptoms:

• Pain

• Inflammation of the throat

• Reddened and/or swollen mucosa

• Swollen tonsils

• Foul-smelling breath

• White packets visible on the walls of the throat (streptococcal disease)

• Sore throats caused by bacteria are more painful than those caused by viruses, and more likely to be accompanied by fever, headache, and nausea.

Pharyngitis

What two bacteria are most serious cases of Pharyngitis

• Streptococcus pyogenes

• Fusobacterium necrophorum

What disease can Pharyngitis cause when invading the bloodstream happens?

Lemierre's syndrome

What antibiotic is Pharyngitis: fusobacterium necrophorum sensitive to?

Penicillin

What is the first choice drug for Pharyngitis: fusobacterium necrophorum?

Clindamycin

• Gram-positive coccus that grows in chains

• Does not form endospores

• Nonmotile

• Does not form capsules

• Facultative anaerobe that ferments a variety of sugars

Does not produce catalase:

Peroxidase system allows for its survival in the presence of oxygen.

What type of pharyngitis?

Streptococcus Pyogenes

Virulence Factors:

• Specialized polysaccharides protect the bacterium from being dissolved by lysozyme.

• Lipoteichoic acid: contributes to the adherence of the cell wall to the epithelial cells of the pharynx

• M protein: resists phagocytosis, contributes to adherence

• Hyaluronic acid capsule: contributes to adhesiveness

Pharyngitis Streptoccus Pyogenes

Streptolysin O and streptolysin S:

• Cause beta-hemolysis of sheep blood agar

• Injure cells and tissues

Extracellular Toxins

• Responsible for the bright red rash

• Induces fever

• Only lysogenic strains of S. pyogenes that contain genes from a temperate bacteriophage can synthesize this toxin.

Erythrogenic Toxin

-Culturing: of pharyngeal swab specimens

• Plated on sheep blood agar

• S. pyogenes causes beta-hemolysis

• Distinguish from beta-hemolytic group B streptococci and enterococci

• Bacitracin disc test

How many types under Rhinoviruses?

99 Serotypes

What is the treatment for Causative agent for sinusitis?

• Various viruses

• Various bacteria, often a mixed infection

• Various fungi

• Allergies, structural abnormalities are common noninfectious causes

What is the treatment for Sinusitis?

Broad-spectrum antibiotics for bacterial infection and antifungals for fungal infection

•Viral infections of the upper ear lead to inflammation of eustachian tubes, buildup of fluid, and bacterial multiplication in the fluid.

Acute Otitis Media

Causative agents:

• Mixed infection of viruses and bacteria

• Mixed biofilm of bacteria in chronic otitis media

Prevention:

• Prevnar

• Hib

Treatment:

• "Watchful waiting"

• Antibiotics

• Tympanic membrane tubes

Acute Otitis Media

How do you prevent Acute Otitis Media?

Prevnar and Hib

•Causative Agent: Bordetella pertussis

•Transmission: Droplet contact

Whopping Cough

How is whooping cough prevented

• DTaP vaccine, antibiotic treatment for contacts

• Vaccine does not provide lifelong immunity

• Many outbreaks today due to lack of vaccination, booster

What are the 3 stages for whooping cough

• Incubation phase: 3 - 21 days

• Catarrhal stage: characterized by runny nose, 1-2 weeks

• Paroxysmal stage: bouts of severe coughing (paroxysm)

• Recovery phase: susceptible to other respiratory infection

How is whooping cough treated?

Azithromycin

What is a reemerging diease?

Tuberculosis

-Minimum infectious dose is about 10 bacterial cells

-Bacteria multiply inside macrophages

-Escape leads to cell-mediated attack on bacteria

-Tubercle formation in lungs

-Neutrophils release enzymes causing necrotic caseous lesions that heal by calcification

-T cell action seen in tuberculin reaction

Primary Tuberculosis

-Infection outside of the lungs:

•Regional lymph nodes

•Kidneys (renal tuberculosis)

•Long bones

•Genital tract (genital tuberculosis)

•Brain and meninges (tubercular meningitis)

-Immunosuppressed patients, young children

-Untreated tubercular meningitis has a 30 - 50% mortality rate.

Extrapulmonary Tuberculosis

-Live bacteria can remain dormant, then reactivate

-Chronic tuberculosis: tubercles expand

-Severe symptoms develop: "consumption"

•Violent coughing with greenish or bloody sputum

•Low-grade fever

•Anorexia, weight loss

•Extreme fatigue, night sweats

•Chest pain

-Untreated secondary disease has a 60% mortality rate.

Secondary Tuberculosis

What strain do you get of tuberculosis that causes an infection from unpasteurized milk?

M. Bovis

Is there any vaccine for Tuberculosis?

No

-Inflammatory condition of the lungs in which fluid fills the alveoli

•Have appropriate characteristics that allow them to penetrate and survive in the lower respiratory tract

•Avoid phagocytosis or avoid being killed once inside phagocytes

Pneumonia

What are the 7 causes of Community Acquired Pneumonia?

•Streptococcus pneumoniae

-40% of community-acquired bacterial cases

•Legionella

-Less common

-Causes serious disease

•Haemophilus influenzae

-Once a major cause

-HIB vaccine reduced its incidence

•Mycoplasma pneumoniae and Chlamydophila pneumoniae:

-Walking pneumonia

•Histoplasma capsulatum: fungus

•Hantavirus

•Pneumonia can be a secondary effect of influenza.

Legionella come from what?

Water

What is walking oneumoniae?

Mycoplasma pneumoniae and Chlamydophila

-Pneumococcus

-Small, gram-positive flattened coccus, often appearing in pairs

-Factors that favor the ability of the bacterium to cause disease:

•Old age

•The season

•Underlying viral respiratory disease

•Diabetes

•Chronic abuse of alcohol or narcotics

Vaccination encouraged with PPSV23

What type of pneumoniae?

Streptococcus oneumoniae

-Weakly gram-negative bacterium that ranges from coccus to filaments

-Able to survive and persist in natural habitats

-Widely distributed in tap water, cooling towers, spas, ponds, and other fresh water

•Resistant to chlorine

•Can live in association with free-living amoebas

-Released during aerosol formation and carried long distances

Legionella nemophila

-Mycoplasma and Chlamydophila

•Transmitted by aerosol droplets among people in confined to close living quarters.

•Family, students, the military

-"Walking pneumonia"

•Lack of acute illness in most patients

Atypical pneumonias

-1993: cluster of unusual cases of severe lung edema among healthy young adults in the Four Corners area

-Bunyaviridae family: enveloped virus

-Associated with the presence of mice in close proximity with humans

•Transmitted via airborne dust contaminated with urine, feces, or saliva of infected rodents

-Localized outbreak in 2012 in Yosemite

Hantavirus

-Endemically distributed in all continents except Australia

-Highest incidence in eastern and central U.S.

-Grows most abundantly in moist soils high in nitrogen content, especially those supplemented with bird droppings

-Extremely widespread distribution measured by injecting fungal extract under the skin

Histoplasma capsulatum

-Discovered in 1909

-Agent of pneumocystitis pneumonia

-One of the most frequent opportunistic infections in AIDS patients

-Likely transmitted through the inhalation of spores

-Traditional antifungal drugs are ineffective against Pneumocystitis pneumonia because of the chemical makeup of the organism's cell wall.

Pneumocystits Jiroveci

•Up to 1% of hospitalized or institutionalized people experience pneumonia:

-Mortality rate: 30 - 50%

-Most frequent causes:

•Pseudomonas aeruginosa

•Acinetobacter baumanii

•Streptococcus pneumoniae

•Klebsiella pneumoniae

•S. aureus: HAP caused by MRSA

•Many are polymicrobial in origin

Healthcare-Associated Penumonia

Presence of virus in the blood

Viremia

Presence of fungi in the blood

Fungemia

Bacteremia

presence of bacteria in the blood

Malaria caused by _____ and ______ are subject to relapses

Plasmodium vivax and P. Ovale

What are the 4 species that are the causative agent for Malaria?

P. Malariae, P. vivax. P. falciparum, and P. ovale

How is Malarie spread?

Anopheles Mosquito

What are disease has symptoms of levels of virus in the blood and levels of t cells in the blood

HIV

What is the causative agent for HIV?

Retrovirus in the genus Lentivirus

This detects several different anti-HIV antibodies and can rule out false positive results

Western Blot

What heart disease has these symptoms? -Fever, fatigue, joint pain, edema of feet, legs, and abdomen, weakness, anemia, abnormal heartbeat, and sometimes symptoms similar to those of a myocardial infarction:

They also have lesions and nodes

Endocarditis

What is a symptom of an enlarged spleen for what heart condition?

Endocarditis

What are the 4 causative agents for acute endocarditis?

Staphylococcus aureus

Streptococcus pyogenes

Streptococcus pneumoniae

Neisseria gonorrhoeae

What are the causative agents for subacute endocarditis?

Streptococci sanguis, S. oralis, or S. mutans