Immune system:

• Phagocytes

• Inflammation

• Fever

• Complement

• Cytokines

Immune system:

• Specialized

lymphocytes

• T cells and B cells

• antibodies

Immune system:

Which are Innate?

1. 1st line

2. 2nd line

3. 3rd line

Immune system:

Which are Adaptive?

1. 1st line

2. 2nd line

3. 3rd line

1st line of defense:

1. Skin

2. Mucous membrane

1st line of defense:

1. Sebaceous (oil) glands

2. Sebum

3. Perspiration (Sweat)

4. Saliva

5. Mucus

6. Gastric juice

7. Vaginal secretions

1st line of defense: chemical factors

- consists of unsaturated fatty acids → inhibits pathogenic bacteria and fungi

- fatty acids + lactic acid → low pH of skin (pH3 – pH5)

- certain bacteria (Propionibacterium acnes) metabolize sebum and form fatty acids that cause inflammation associated with acne

1st line of defense: chemical factors

- flushes microbes from pores and surface of skin

- contains lysozyme (antimicrobial enzyme)

1st line of defense: chemical factors

- enzyme capable of degrading peptidoglycan in cell walls of Gram +ve bacteria and to a lesser extent Gram-ve bacteria

1st line of defense: chemical factors

– a protein that binds iron, a mineral that is required by all pathogens. Found in milk, saliva, tears and nasal secretions. Added to baby formulas.

1st line of defense: chemical factors

– an enzyme that catalyzes production of superoxide radicals (highly reactive forms of oxygen) toxic to bacteria. It is secreted from mammary, salivary, and other mucosal glands

1st line of defense: chemical factors

Vaginal secretions

- glycogen produced by vaginal epithelial cells broken down into lactic acid by Lactobacillus acidophilus → pH (?)

- cervical mucus has antimicrobial properties

Phagocytosis:

- attracted by chemokines

Phagocytosis:

- attached to microbes by receptors

Phagocytosis:

- extend pseudopodia around microbes

Phagocytosis:

- digest microbes with enzymes

Fever:

- substance that induces fever

- lipopolysaccharide (LPS) from Gram-ve bacteria

- cytokines (body) e.g. interleukin-1(IL-1)

3rd line of defense: adaptive immunity

• B cells

• Involves antibodies

• Extracellular pathogens

3rd line of defense: adaptive immunity

• T cells

• Direct killing

• Intracellular pathogens

Cells of adaptive immunity:

• Helper T (TH) cells

• Cytotoxic T (Tc) cells

Cells of adaptive immunity:

• produce antibodies

Cells of adaptive immunity:

• CD4+

• Secrete cytokines

• TH1 – support cell-mediated immune response (macrophage, Tc, NK)

• TH2 – support humoral response and activate B cells

Cells of adaptive immunity:

• CD8+

• Kill pathogen, virus-infected cells, tumour cells

Antigens:

require participation of helper T cells, as well as macrophages and B cells

Antigens:

require only B cells; usually polysaccharides (endotoxin LPS) found in cell walls of Gram-ve bacteria, bacterial flagella, bacterial capsules

Active vs. Passive Acquired immunity:

- Active- antigen enters the body naturally

- Passive- antibodies pass from the mother to the fetus via the placenta or to the infant via mother’s milk

Active vs. Passive Acquired immunity:

- Active- antigen is introduced in the form of a vaccine

- Passive- preformed antibodies in the immune serum are introduced by injection

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

- represent 90% of normal skin microbiota, coagulase-negative

➢Pathogenic only when skin barrier is broken; a healthcare-associated pathogen; produces biofilm on catheters

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

- carried in the nasal passages of 20% of the population, coagulase-positive; forms golden-yellow colonies

➢Produce damaging toxins to cause sepsis or enterotoxins to affect gastrointestinal(GI) tract

➢Avoids host defence by: secreting a protein to block chemotaxis of neutrophils to the infection site on the skin; secreting toxins that kill phagocytic cells; secreting proteins to neutralize the antimicrobial peptides.

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

- a type of impetigo

- Bullous impetigo

• Toxic shock syndrome (TSS)

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

• >80 immunological types according to the M protein

• Produce virulence factors

➢ Streptolysins that lyse RBCs and are toxic to neutrophils

➢ M proteins on GAS are located external to the cell wall; allow adherence and immune system avoidance

➢ Hyaluronidase: dissolves connective tissue

➢ Streptokinases: dissolve blood clots

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

infections of the hair follicles (pimples)

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

folliculitis of an eyelash

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

a type of abscess; localized region of pus surrounded by inflamed tissue

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

damage and inflammation of deep tissue from a spreading furuncle; usually presented with fever

Bacterial Diseases of the Skin - Staphylococcal Skin Infections:

contagious skin infection, crusting(non-bullous) sores, spread by autoinoculation (infection of surrounding areas)ed with fever

Staphylococcal scalded skin syndrome (SSS):

➢Caused by a staphylococcal exotoxins which leads to exfoliation 剝脫 (separation of the skin layer)

🞄Exfoliative toxin A: localized

🞄Exfoliative toxin B: circulates to distant sites

➢Pemphigus neonatorum: impetigo of the newborn

Staphylococcal scalded skin syndrome (SSS):

Fever, vomiting, shock, &organ failure caused by toxic shock syndrome toxin 1 (TSST-1) in blood

Group A streptococci (GAS):

➢ S. pyogenes infects the dermal layer of the skin with well demarcated boundaries, forms reddish patches with raised margins

➢ Causes local tissue destruction, or enters bloodstream to cause sepsis

➢ Sepsis is a serious condition in which the body responds improperly to an infection. The infection-fighting processes turn on the body, causing the organs to work poorly.

➢ Sepsis may progress to septic shock. This is a dramatic drop in blood pressure that can damage the lungs, kidneys, liver and other organs. When the damage is severe, it can lead to death.

➢ Early treatment of sepsis improves chances for survival.

Group A streptococci (GAS):

Caused by “Flesh-eating bacteria”

➢ Exotoxin A produced by S. pyogenes acts as a superantigen

Group A streptococci (GAS):

➢ Similar to staphylococcal toxic shock syndrome

• Pseudomonads aeruginosa: Gram- (?), aerobic rod

➢ Produces a bacterial pigment (pyocyanin); resulting in a blue-green pus

➢ Produces exo- and endotoxins

➢ Grows in biofilms, resistant to many antibiotics

➢ Opportunistic in burn patients

• Pseudomonas dermatitis

➢A self-limiting rash associated with swimming pools

• Otitis externa

Viral Diseases of the Skin:

• Mild disease contracted usually in childhood; causes pus- filled vesicles

• Caused by Herpesvirus Varicellovirus (A Varicella-zoster species, human herpesvirus)

• Transmitted via the respiratory route

Viral Diseases of the Skin - Herpes Simplex:

• ~90% of the population is infected; usually develop as cold sores or fever blisters: painful, short-lived vesicles at outer red margin of the lips (Not the cause of canker sores)

• remains latent in trigeminal nerve ganglia

• Outbreaks are triggered by the sun, stress, or hormonal changes

• Herpes gladiatorum: vesicles on the skin

• Herpetic whitlow: vesicles on the fingers

Viral Diseases of the Skin - Herpes Simplex:

• remains latent in sacral nerve ganglia near the spine

• Herpes encephalitis: virus spreads to the brain

• Infection is more serious (70% fatality rate if untreated)

• Treated with acyclovir

Viral Diseases of the Skin:

• Viral disease transmitted by the respiratory route, highly contagious

• Cold-like symptoms, macular rash on body, Koplik’s spots (Red spots on the oral mucosa opposite the molars)

• Encephalitis about 1 in 1,000 cases of measles victims;

• Subacute sclerosing panencephalitis, rare complication of measles (1 in 1,000,000), occurs 1 to 10 years after measles recovery

• Prevented by the MMR (measles, mumps, rubella) vaccine

• Children under 1 year old should not receive the vaccine (because it is not effective)

Viral Diseases of the Skin:

• Caused by Rubella virus

• Symptoms: Macular rash and light fever

• Transmitted via the respiratory route; 2 to 3 weeks incubation

• Congenital rubella syndrome: Birth defects associated with maternal infection including fetal damage, deafness, heart defects, mental retardation; 15% mortality

• Prevented by the MMR vaccine but not recommended for pregnant women

Bacterial Diseases of the Eyes:

• Caused by Neisseria gonorrhoeae

• Large amount of pus forms; ulceration of corneas results

• Untreated cases may lead to blindness

• Transmitted to a newborn’s eyes during passage through the birth canal

• Prevented by treating a newborn’s eyes with antibiotics

Bacterial Diseases of the Eyes:

• Caused by Chlamydia trachomatis

• Bacterium that grows as an obligate intracellular parasite

• Transmitted to a newborn’s eyes during passage through the birth canal

• Spread through swimming pool water

• Treated with tetracycline

Bacterial Diseases of the Eyes:

• Caused by some serotypes of Chlamydia trachomatis

• Leading cause of blindness worldwide

• Transmitted via hand contact or flies

• Infection causes permanent scarring; scars abrade cornea, causes blindness

• Secondary infections can also be a factor

• Oral azithromycin for treatment

Staphylococcal enterotoxicosis /Staphylococcal Food Poisoning

🞄 Fairly high resistance to heat

🞄 Vegetative cells can tolerate 60°C

🞄 Resistance to drying and radiation (survive on skin surface)

🞄 Resistance to osmotic pressure (grow in food)

Shigellosis (Bacillary Dysentery)

• Caused by a group of facultatively anaerobic gram-(?) rods of the genus Shigella, Shiga toxin

Salmonellosis(Salmonella Gastroenteritis)

• Caused by the Salmonella bacteria, e.g. Salmonella enterica

• Gram-(?), facultative anaerobic, non-endospore forming rods

Typhoid Fever

• Most virulent serotype of (?)

• Caused by (?) typhi

Helicobacter Peptic Ulcer

• People with blood type (?) are more susceptible

• Gastric cancer develops in about 3% of people infected with these bacteria

Helicobacter Peptic Ulcer, Treatment:

to kill the bacterium including amoxicillin (Amoxil), tinidazole (Tindamax), clarithromycin (Biaxin), metronidazole (Flagyl), tetracycline, levofloxacin.

Helicobacter Peptic Ulcer, Treatment:

to reduce stomach acid by blocking the action of the parts of cells that produce acid. These drugs include the prescription and over-the- counter medications omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), esomeprazole (Nexium) and pantoprazole (Protonix).

Helicobacter Peptic Ulcer, Treatment:

to reduce the amount of stomach acid released into your digestive tract, Antacids neutralize existing stomach acid and can provide rapid pain relief

Helicobacter Peptic Ulcer, Treatment:

that help protect the tissues that line your stomach and small intestine.Options include the prescription medications sucralfate (Carafate) and misoprostol (Cytotec).

Clostridium perfringens gastroenteritis

• Caused by Clostridium perfringens

🞄 Large, gram (?), endospore forming, obligate anaerobic rods

🞄 Human gas gangrene

• Grows in intestine and produce exotoxin ➔ diarrhea and abdominal pain

• Symptoms occur around 8-12 hours after ingestion

Hepatitis

• Single stranded RNA without envelope (grow in culture)

• Virus enters via oral route, then multiplies in the epithelial lining of the intestinal tract

• Virus spreads to liver, kidneys and spleen via blood

• Amount of virus excreted is greatest before symptoms appear and declines rapidly

• Virus survives for several days on surfaces as cutting boards and is resistant to chlorine

• Mollusks, such as oysters live in contaminated waters are a source of infection

• Jaundice and dark urine typical of liver infections

• Virus usually shed only during acute stage of disease, no chronic form

Hepatitis

• Diagnosis: Detection of IgM anti-HAV (appear 4 weeks after infection and disappear 3-4 months post-infection)

• Treatment

o No special treatment

o Give immune globulin prophylactically for high-risk cases

o HAV vaccination as childhood vaccination schedule

• High risk group: homosexual men and injecting drugs users

Hepatitis

o Larger, double stranded DNA with envelope

o Virus passes through an intermediate RNA stage resembling a retrovirus

• Transmitted by blood transfusions (50% HBV carriers are caused by carrier mother to born infants)

• Serum of HBV-infected patients: Dane particles, spherical particles and filamentous particles

• Virus also present in body fluid: blood, saliva, breast milk, semen (but not in blood-free feces and urine)

• May become chronic and high incidence of liver cancer or liver cirrhosis

Hepatitis

• Treatment:

o Antiviral medications including pegylated interferon alfa, entecavir (Baraclude), tenofovir (Viread), lamivudine(Epivir), adefovir (Hepsera) and telbivudine (Tyzeka)

Hepatitis

(single stranded RNA with envelope)

• Capable of genetic variation to evade the immune system ➔ complicate the search for effective vaccine

Hepatitis

• Acute (co-infection form) and chronic (super infection form)

Hepatitis

• Endemic in areas with poor sanitation

• Spread by food or water contaminated by cysts of amoeba Entamoeba histolytica

• Stomach acid can destroy trophozoites but does not affect the cysts

• Severe dysentery results, and feces with blood and mucus results

• Treatment: Metronidazole followed with paromomycin

• Upper respiratory infection, transmitted by respiratory route

• Characterized by local inflammation, fever, tonsillitis (often), enlarged lymph node

• Caused by Streptococcus pyogenes

o Gram positive, group A beta-hemolytic streptococci (GAS)

• When Streptococcus pyogenes causing streptococcal pharyngitis produces erythrogenic (reddening) toxin

oCauses the pinkish red skin rash (hypersensitive reaction to the circulating toxin) and high fever

oTongue: spotted, strawberry-like appearance (loses its upper membrane) and becomes very red and enlarged

• Begins with sore throat and fever followed by general malaise and swelling of the neck

• Caused by Corynebacterium diphtheriae

o Gram positive, non-endospore forming rod

o Plemorphic, club-shaped

o Forms a tough grayish membrane in the throat (fibrin dead tissue, block the passage of air to the lungs)

o Damages heart and kidneys(or other organs) ➔ fatal

▪ Antibiotics DO NOT neutralize the diphtheria toxin

▪ Antibioticsshould be used in conjunction with antitoxin which counteracts the diphtheria toxin

• Caused ➔ slow-healing ulcerations covered by gray membrane

• Respiratory cases arise from contact with cutaneous diphtheria

• Caused by Bordetella pertussis

• Small, obligate aerobic gram-negative coccobacillus

• Virulent strain possesses a capsule

o Attaches to ciliated cells in the trachea, impeding their ciliary action, then destroys the cells, this prevents ciliary escalator system

• Produces several toxins

oTracheal cytotoxin, damages ciliated cells

oPertussis toxin, enters the blood stream, associated systemic symptoms of the disease

• Infectious disease caused by Mycobacterium tuberculosis (other cause: Mycobacterium bovis)

oSlender rod and obligate aerobe

oGrows slow and appear mold-like (20-hr generation time)

oStained by acid-fast (Mycolic acid) ➔ reflect large amount of lipid in cell wall (unusual) ➔ Survive for weeks in dried sputum and resistant to antiseptics and disinfectants as well as drying

Tuberculosis, Treatment:

isoniazid, rifampin, ethambutol, pyrazinamide

Tuberculosis, Treatment:

aminoglycosides, fluoroquinolones, para-aminosalicyclic acid

Pneumonia:

Streptococcus pneumoniae

Pneumonia:

Fungi, protozoa, viruses, other bacteria (slow onset, less chest pain and fever)

• Caused by Streptococcus pneumoniae

oGram positive, ovoid bacterium

oNo bacterial toxin is clearly related to the pathogenicity

• Symptoms: High fever, breathing difficulty, chest pain, sputum (rust-colored)

• Lungs appear reddish because blood vessels are dilated

• Infected alveoli of lungs filled with red blood cells, fluids and neutrophils; this interferes with oxygen uptake

• Prevention: Pneumococcal vaccine

• Aerobic and gram-negative rod

oFound in natural water, water of air-conditioning cooling towers, whirlpool spas, humidifiers, showers, decorative fountains, potting soil

• Transmitted by inhaling aerosols, not transmitted from human to human

• Symptoms: High fever (40.5 degree C), cough, general symptoms of pneumonia. Similar to Pontiac Fever

• Most common cause of viral respiratory diseases in infants

• Causes cell fusion (syncytium) in cell culture

• Symptoms: coughing, wheezing > 1 week , fevers occur when there are bacterial complication

• Treatment: palivizumab

• Chills, fever, headache and muscle aches (No intestinalsymptoms)

🞄 Virus consists of 8 separate RNA segments of different lengths enclosed by inner protein and outer lipid bilayer

• Antigenic shift: caused by major genetic recombination to evade most immunity (reassortment of RNA segments)

o Minor annual variations in the antigenic makeup: Antigenic drift, allow the virus to elude much hosts immunity

Prone to outbreak and pandemics

• 1% mortality; usually the very young and very old

• Multivalent vaccine for the most important strains

Treatment:

• The antiviral drugs oseltamivir (Tamiflu®), zanamivir (Relenza®), and peramivir (Rapivab®) significantly reduce the symptoms of influenza A if administered promptly.

• They are inhibitors of neuraminidase

• If taken within 24 hours of onset of influenza, these drugs slow replication. This action allows the immune system to be more effective, which shortens durations of symptoms and lowers the mortality rate.

• Coronaviruses are a large family of viruses, some cause illness in humans, and others cause illness in animals, such as bats, camels, and civets.

• The virus that causes Covid-19 is knownas SARS-CoV-2, enveloped virus, single-stranded RNA (+ sense)

• SARS-CoV-2 is a new strain of coronavirus that previously has not been identified in humans

• The most common symptoms of COVID-19 include fever, dry cough and fatigue.

• Some people who contracted the infection have only very mild or non-specific symptoms, while some may develop severe symptoms like shortness of breath, chest pain or confusion

• According to the World Health Organization, about 20% of the cases may develop serious illness with breathing difficulty.

• People of an older age or having underlying diseases (e.g. hypertension, heart and lung problems, diabetes, or cancer) are at a higher risk of deterioration into a serious condition.

Influenza

agglutination of red blood cells that occurs when viruses are mixed with them; Used for attachment to host cells before infection

🞄 Antibodies against the influenza virus are directed at these spikes

Influenza

Enzymatically help the virus separate from the infected cell as virus exits after intracellular

reproduction

🞄 Stimulate the formation of antibodies

• Also called endotoxin shock

• Endotoxins (lipopolysaccharides [LPS]) (cause a severe drop in blood pressure

• The most common treatment for sepsis caused by Gram-positive and Gram- negative bacteria is the use of antibiotics.

• Antibiotics can worsen the condition by killing bacteria. The highest concentration of bacterial endotoxins during sepsis treatment is due to bacterial lysis caused by antibiotics, which causes the lipopolysaccharides (LPS) that constitute the cell wall of bacteria to be released into the environment.

• Treatment involves neutralizing the LPS components

• Potent exotoxins that cause toxic shock syndrome

• Hospital-acquired infections (Nosocomial infections)

o Enterococcus faecium and Enterococcus faecalis

▪ Inhabit the colon,Colonize wounds and the urinary tract

▪ Resistant to many antibiotics

o Group B streptococci (GBS)

▪ Streptococcus agalactiae

❖ Neonatalsepsis

o Caused by Streptococcus pyogenes

o Transmitted to the mother during childbirth

▪ Infects the uterus and progresses to an infection of the abdominal cavity (peritonitis)

▪ Treatment with oral antibiotics, e.g. clindamycin (Cleocin) or gentamicin (Gentasol)

Bacterial Infections of the Heart:

o Impairsthe function of the heart valves

o Alpha-hemolytic streptococci from an oral or tonsil infection

Bacterial Infections of the Heart:

o Caused by Staphylococcus aureus

• Caused by Bacillus anthracis

o Gram-positive, endospore-forming aerobic rod

• Found in soil

• Primarily affects grazing animals

• Spores introduced into the body are taken up by macrophages and germinate. Bacteria enter the bloodstream and release toxins

• Treated with an antibiotic such as ciprofloxacin (Cipro), doxycycline (Vibramycin)

• Vaccination of livestock

o Caused by Clostridium perfringens, a gram-positive, endospore-forming anaerobic rod

▪ Grows in necrotic tissue

▪ Produces toxins that move along muscle bundles

o Treatment includes antibiotics, surgical removal of necrotic tissue and/or use of

a hyperbaric chamber. The earlier gangrene is identified and treated, the better the chances for recovery.

o Caused by Rickettsia prowazekii

o Carried by the body louse: Pediculus humanus corporis

o Transmitted when louse feces are rubbed into the bite wound from the louse

o Prolonged fever and a rash of red spots due to subcutaneous hemorrhaging

o Treatment with tetracycline. A single dose of doxycycline has proved effective against epidemic typhus. Doxycycline also works quickly on other strains of the disease. For the best results, take it as soon as possible after the symptoms start. If there is allergic to doxycycline or if it does not work, doctors may choose another antibiotic such as ciprofloxacin (Cipro) and chloramphenicol.

• Tumor the of jaw

o Due to Epstein-Barr virus (human herpesvirus 4)

• Malaria suppresses the immune response to the virus

• Usually treated with a number of different chemotherapy drugs and a targeted immunotherapy drug called rituximab (Mabthera). The combination therapy is called chemoimmunotherapy. It can be very intensive lasting for several months.

Anthrax, Bacteria produce virulence factors:

binds the toxins to target cells, permitting their entry

Anthrax, Bacteria produce virulence factors:

causes local swelling and interferes with phagocytosis

Anthrax, Bacteria produce virulence factors:

targets and kills macrophages

Anthrax, Bacteria produce virulence factors:

that avoids an immune response

Anthrax:

o Endospores enter through a minor cut

o 20% mortality rate if untreated

Anthrax:

o Ingestion of undercooked, contaminated food

o 50% mortality rate

Anthrax:

o Inhalation of endospores

o Bacteria enter the bloodstream; infection progresses into septic shock

o Near 100% mortality rate

• Caused by Epstein-Barr virus

• Childhood infections are often asymptomatic

• Transmitted via saliva; incubation of 4 to 7 weeks

• Fever, sore throat, swollen lymph nodes, enlarged spleen

• Replicates in resting memory B cells

o Forms unusual lobed nuclei

o Produces heterophile antibodies, generally weak antibodies with multispecific activities

• No specific therapy available to treat infectious mononucleosis. Antibiotics do not work against viral infections. Treatment mainly involves taking care of oneself, such as getting enough rest, eating a healthy diet and drinking plenty of fluids. One may take over-the-counter pain relievers to treat a fever or sore throat.

• Remains latent in white blood cells

• Infected cells swell

o Form “owl’s eyes” inclusions

• May be asymptomatic or causes mild symptoms in adults. Ganciclovir (Cytovene) given intravenously, is the drug of choice for the treatment of CMV infection.

• Cytomegalic inclusion disease (CID)

o Transmitted across the placenta; causes mental retardation or hearing loss in newborns (neonates)

• Transmitted sexually, via blood, saliva, or transplanted tissue.

• Good hygiene and especially washing the hands thoroughly to prevent transmission of the illness. Healthy people who get infected by CMV normally don’t need a special therapy; the disease heals without treatment. But the virus stays in the body.

virus is injected into the skin through Aedes aegypti (mosquito) bites

• Fever, chills, headache, nausea, vomiting

• Jaundice due to liver damage. “Yellow” in the name refers to the jaundice that affects some patients.

• Endemic in tropical areas

• No specific antiviral drugs; attenuated vaccine available.

• Use insect repellent, wear long-sleeved shirts and long pants.

transmitted by A. aegypti

• Endemic to the Caribbean and tropical environments

• Asymptomatic and mild to severe bleeding and organ impairment

• No animal reservoir

• No vaccine or effective drug treatment. Rest as much as possible. Take acetaminophen (known as paracetamol outside US) to control fever and relieve pain. Drink plenty of fluids to stay hydrated.

o Caused by the Ebolavirus

o Reservoir is the cave-dwelling fruit bat

o Spread by contact with infected body fluids

o Damages blood vessel walls and interferes with coagulation.

▪ Blood leaks into surrounding tissue.

o Mortality rate of 90%

o U.S. Food and Drug Administration approved Inmazeb (atoltivimab, maftivimab, and odesivimab-ebgn), a mixture of three monoclonal

antibodies, as treatment for Zaire ebolavirus infection in adult and pediatric patients.

Other Diseases and Epstein-Barr Virus include?

1. Multiple sclerosis

2. Hodgkin’s lymphoma

3. Nasopharyngeal cancer

• Gram-negative aerobic bacteria; normal throat microbiota

• Can enter the bloodstream

• Pathogenicity due to capsule antigen type b

• Occurs mostly in children (6 months to 4 years)

• Prevented by the Hib vaccine

• Accounts for 45% of bacterial meningitis cases; 6% mortality

• Ceftriaxone is one of the most commonly used antibiotics. Ampicillin may sometimes be used. Corticosteroids may be used to fight inflammation, especially in children. Unvaccinated people in close contact with people with H influenzae meningitis should be given antibiotics to prevent infection.

• Gram-negative aerobic cocci with a capsule

oSix serotypes associated with the disease

• Forty percent of people are healthy nasopharyngeal carriers

• Begins as a throat infection, rash, and bacteremia

• Mortality of 9-12% with antibiotic therapy; 80% without

• Outbreaks common in dorms and military barracks

• Vaccination protects vs serogroups A, C, Y, and W, but not B

• Gram-positive encapsulated diplococcus

• Seventy percent of people are healthy nasopharyngeal carriers

• Also causes pneumonia and otitis media

• Most common in children (1 month to 4 years)

• Mortality: 8% in children, 22% in the elderly

• Prevented by conjugated vaccine.

• Requires immediate treatment with antibiotics. Delays in implementing treatment are not acceptable. Penicillin, with vancomycin (or chloramphenicol) being a reasonable alternative in patients allergic to penicillin

• Diagnosed from bodily fluids with the direct fluorescent-antibody (DFA) test

• Postexposure prophylaxis (PEP): vaccine plus immune globulin

o Human diploid cell vaccine (HDCV)

o Human rabies immune globulin (RIG)

• Treatment- Once a rabies infection is established, there’s no effective treatment. Though a small number of people have survived rabies, the disease usually causes death. For that reason, if you think you’ve been exposed to rabies, you must get a series of shots to prevent the infection from taking hold.

• Japanese encephalitis

o Found in the Far East and South Asia

o One percent show symptoms, but there is a 20-30% mortality in those with symptoms

• Diagnosed by ELISA tests (to identify IgM antibodies)

• Prevention: controlling mosquitoes

Cryptococcus neoformans Meningitis

• Soil fungus associated with pigeon and chicken droppings

African Trypanosomiasis

• Parasite evades antibodies through antigenic variation

o Difficult for vaccine development

• Treated with eflornithine: crosses the blood-brain barrier; blocks an enzyme necessary for the parasite

• Unlike bacteria and viruses, prion diseases are irreversible and can not be overcome by the body’s immune system. There are no drugs for the treatment of prion diseases.

• Prions are difficult to destroy via standard methods

Bacterial Diseases of the Urinary System:

oAn inflammation of the urinary bladder

Bacterial Diseases of the Urinary System:

oAn inflammation of one or both kidneys

Bacterial Diseases of the Urinary System:

oA disease of animals, can be passed to human and causes severe kidney or liver disease

• Inflammation of the bladder; the most common site of UTI and is usually mild and uncomplicated

• More common in women due to the short and straight urethra and its close proximity to vagina and anus → increased possibility of bacteria contamination

• In adult male, incomplete bladder emptying and urinary stasis commonly caused by benign prostatic hyperplasia (BPH) can contribute to UTI development

Mode of Spread of Infection:

• Ascending infection:

o the most common

o ascends from urethra → bladder → kidneys

• Haematogenous: via blood stream

• Descending infection: (rare)

• Difference between signs and symptoms

• a sign is a manifestation of disease that the physician(doctor) perceives. Symptoms represent the complaints of the patient

Diagnosis

• A urine sample with more than 1,000 colony forming units (CFU) per millilitre of a single species indicates cystitis.

• A positive urine test for leukocyte esterase (LE)suggests there are white blood cells in the urine caused by a urinary tract infection

• Treatment

The preferred antimicrobial agents for therapy of acute simple cystitis are nitrofurantoin monohydrate/macrocrystals, trimethoprim-sulfamethoxazole, fosfomycin, and pivmecillinam.Nitrofurantoin usually clears cystitis quickly.A fluoroquinolone is often successful if there is drug resistance. Pyridium (Phenazopyridine) is a pain reliever for UTI and is used to treat pain or burning, increased urination, and increased to urinate.

• Drink plenty of water

Infection of one of the upper urinary tracts or both left and right urinary tracts (ureter, renal pelvis, and kidney interstitium); most commonly caused by bacteria

• Usually a result of bacterial infection ascending from the lower tract

• Urinary obstruction and urinary reflux from the bladder are the 2 most common underlying risk factors

• E. coli, Proteus and Pseudomonas are the commonly associated microorganisms

Signs and Symptoms:

• Acute onset

• Fever, chills

• UTIsymptoms

• Haematuria; turbid urine

• Flank or groin pain

• Nausea and vomiting

• Zoonotic disease that causes severe kidney or liver disease

• Usual causative agents: Spirochete Leptospira interrogans

• Symptoms:

o Headaches, muscular aches, chills, fever

o Complication: kidney failure

• Transmission: Urine-contaminated water orsoil

• Diagnosis: Serological tests

• Treatment:

o Antibiotic, e.g. Doxycycline or penicillin, which should be given early in the course of the disease.

o Intravenous antibiotics may be required for persons with more severe symptoms.

• Most common reportable communicable in US

• Causative agent: Neisseria gonorrhoeae (Gram -ve)

• Anal gonorrhea, pharyngeal gonorrhea

• Attaches to oral or urogenital mucosa by fimbriae

o Opa protein variant of gonococcus binds to the receptor on CD4+T cells of the host’s urinary and reproductive tracts

o This inhibits the development of an immunological memory response againstthe gonococcus

• Also known as non-specific urethritis

• Causative agents:

o Chlamydia trachomatis

o Myoplasma hominis

o Ureaplasma urealyticum

• Symptoms: painful urination and watery discharge. In women, possible complications, such as Pelvic inflammatory disease (PID).

• Diagnosis: Polymerase chain reaction(PCR)

• Treatment: Doxycycline taken twice a day for 7 days and azithromycin taken just once as a single dose

• Collective term for any extensive bacterial infection of the female pelvic organs (uterus, cervix, uterine tubes, ovaries)

• Causative agents:

o N. gonorrhoeae C. trachomatis

• Symptoms: Chronic abdominal pain; possible infertility

• Diagnosis: Signs and symptoms in association with gonorrheal or chlamydial infections

• Treatment: Cefoxitin, a second-generation cephalosporin, in combination with probenecid and doxycycline

• Causative agent: Treponema pallidum

• Loses infectiveness outside mammalian host within a short time

• T. pallidum, no virulence factors such as toxins, but produces lipoproteins that induce inflammatory immune response

o Invades mucosa or through skin breaks

o Organism enters bloodstream and invades deeper tissues

• Transmitted by sexual contact via syphilitic infections of the genitals or other body parts

• Incubation: averages 3 weeks

• Progresses through 4 stages

• Treatment:

o The preferred treatment at all stages is a single injection of penicillin. In case of penicillin allergy, another antibiotic or penicillin desensitization is recommended. Additional doses for syphilis >1 year.

Syphilis:

o Chancre (sore) at site of infection

o Painless, with exudate of serum forms in centre

o Fluid is highly infectious

o Then lesions disappear

o Women: cervix

o Men: urethra

Syphilis:

o Skin and mucosal rashes, especially visible on palms and soles

o Lesions of the rash contain spirochetes, very infectious

o Usually resolve within 3 months

Syphilis:

o Fetal death or birth defects,Neurological damage

• Causative agents: herpes simplex virus type 2 (human herpes virus 2, or HSV –2)

• Symptoms:

o painful vesicles on genitals, burning sensation

o Painful urination

o Vesicles healed after couple of weeks

• Neonatal herpes transmitted to fetus or newborns

• Recurrences from viruses latent in nerves

• Caused by virus: human papillomaviruses (HPV)

• Symptoms: Wartsin genital area

o transmitted sexually

o Some are large, resembling cauliflower

• Diagnosis: Microscopic appearance of infected cells, PCR

• Treatment: Podofilox cream; imiquimod (Aldara, Zyclara) cream, Sinecatechins (Veregen) cream, Trichloroacetic acid to burn off genital warts

• Prevention:

o Use condoms

o Vaccination against HPV strains

o Gardasil and Cervarix

• Opportunistic infections

o Protozoal (e.g. Pneumocystis, Toxoplasma)

o Bacterial (e.g. Mycobacterium, Treponema)

o Fungal (e.g. Candida, Cryptococcus, Histoplasma)

o Viral (e.g. Cytomegalovirus, Herpes simplex virus)

• Malignancies

• Neurological symptoms: aseptic meningitis, myelopathies, neuropathies, AIDS dementia complex

• Causative agent: Candida albicans and other Candida speciese.g.C glabrata

• Most common cause of vaginitis and vulvovaginitis

• Grows on mucosa of mouth, intestinal tract, and genitourinary tract

• Symptoms: Severe vaginal itching, yeasty odor, yellow discharge

• Diagnosis: microscopic and culture • Treatment: IV echinocandin (caspofungin, micafungin, or anidulafungin), fluconazole, amphotericin B, & other antifungal drugs

• Causative agent: Trichomonas vaginalis

• Found in vagina in female and urethra in men

• Transmission: Sexually transmitted

• Symptoms:

• In female, vaginal infection causes irritation and profuse greenish yellow frothy discharge.

• In male, itching or irritation inside the penis, burning sensation after urination or ejaculation, or discharge from the penis

• Diagnosis: microscopic identification of protozoan, DNA probeDNA, monoclonal antibodies

• Treatment: Metronidazole

HIV AND AIDS:

(1)Binding to molecules on the host CD4 cell surface

(2)Fusion: HIV viral envelope fuses with the CD4 cell membrane, and then

(3) Reverse transcription: HIV uses a reverse transcriptase enzyme to convert its RNA into DNA.

(4)Integration: HIV enters the host CD4 cell's nucleus, where it uses its integrase to insert its viral DNA into the host DNA.

(5)Replication: HIV uses the machinery inside the CD4 cell to create proteins, the building blocks for more HIV.

(6)Assembly: the new HIV RNA and HIV proteins move to the surface of the cell and form immature (noninfectious) HIV.

(7)Budding: This immature HIV forces its way out of the host CD4 cell. HIV protease breaks up the long protein chains in the immature virus , creating the mature and now infectious virus, ready to infect other CD4 cells.

Ways of HIV transmission:

1. Sexual contact

2. Contact with blood, semen, pre-seminal fluid, vaginal fluids, rectal fluids

3. Breast milk

4. Transplacental infection of fetus

5. Blood-contaminated needles

HIV & AIDS Prevention:

1. Use condom properly during each sexual contact

2. Maintain a mutually monogamous relationship with an uninfected partner

3. Avoid sharing needles

4. Pre-exposure prophylaxis(PrEP)

5. Early treatment

Nosocomical pneumonia or hospital-acquired pneumonia (HAP) is defined as pneumonia that occurs (?) after hospital admission and not incubating at the admission time.

Ventilator-associated pneumonia (VAP) represents a significant sub-set of HAP occurring in intensive care units (ICUs) and is defined as pneumonia that occurs (?) after tracheal intubation and is thought to affect 10% to 20% patients receiving mechanical ventilation for more than 48 hours

Nosocomical surgical site infections (SSIs)

Postoperative wound infection can occur from the first day onwards to many years after an operation but commonly occurs between the (?) days after surgery.

Nosocomical surgical site infections (SSIs)

The most common of these bacteria is?

Nosocomical urinary tract infections (UTIs)

Most CAUTIs derive from the patient's own colonic flora and the commonest infecting organism is?

Antibiotic Resistant Bacteria:

- This strain of the common "staph" bacteria causes infections in different parts of the body including the skin, lungs, and other areas

- Resistant to certain antibiotics called beta-lactams, e.g. methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin

- Intravenous vancomycin

Controlling the spread of antibiotic resistance bacteria:

1. Hand hygiene

2. Contact precautions

3. Tracking the incidence and frequency of certain antimicrobial-resistant pathogens

4. Screening of high-risk patients with active surveillance

5. Improving antibiotic prescribing/stewardship

6. Developing new drugs and diagnostic tests

COMMUNITY ACQUIRED INFECTIONS (CAIs):

For infection to occur, we need?

1. susceptible host

2. pathogen

3. mode of transmission

GENERAL APPROACHES IN PREVENTIONAND CONTROL OF CAIs:

sterilization and disinfestation

GENERAL APPROACHES IN PREVENTIONAND CONTROL OF CAIs:

preventing breeding of vectors

GENERAL APPROACHES IN PREVENTIONAND CONTROL OF CAIs:

1. Measures targeting the susceptible host

2. Vaccination

3. Chemoprophylaxis

4. Maintaining a healthy lifestyle

5. Limiting exposure to reservoirs of infection