Infectious Diseases Quiz

Diseases of the Urinary and Reproductive Systems (Genitourinary Tract)

• The genitourinary tract is comprised of two distinct systems: the urinary tract and the genital system (also known as the reproductive system).
• The urinary tract removes metabolic wastes from the blood through the kidneys, regulates bodily processes, and transports urine out of the body.
• The genital system functions mainly in reproduction.

The Urinary System

• The urinary tract consists of the kidneys, ureters, bladder, and urethra.
• Kidneys filter metabolic waste from blood.
• Ureters transport urine from kidneys to the bladder.
• The bladder stores urine.
• The urethra carries urine to the external environment.
• Pathogens can enter the urinary tract in some cases.

Urinary Tract Defenses

• Urine flushing action helps to remove pathogens.
• Desquamation, the sloughing of epithelial cells, helps remove microbes.
• Normal flora (helpful bacteria) in the urethra inhibits pathogenic bacteria growth.
• Antibacterial proteins like lysozyme, lactoferrin, and secretory IgA combat infection.

General Terms for Urinary Tract Infections (UTIs)

• Pyelonephritis: Kidney infection, can cause sepsis.
• Cystitis: Urinary bladder infection.
• Urethritis: Urethra inflammation.

Diagnosis

• Quantitative urine culture on blood and MacConkey agar.
• Quantification of urine by a calibrated pipette.
• Counting colonies to obtain CFU/mL.

Urine Specimen Types

• CCMS (Clean Catch, Mid-stream): Common method for specimen collection.
• Suprapubic aspirate: Urine sample collected directly from the bladder.
• Catheterized specimen: Direct collection of urine via catheter.

Screening Urine Specimens for Bacteria

• Dipstick method: Simple tests detecting leukocyte esterase and nitrates.
• Leukocyte esterase indicates presence of neutrophils-infection.
• Nitrites indicate presence of bacteria.

Urethritis due to Coliforms

• E. coli is a common gram-negative rod; often causing UTIs.
• Other coliforms (like Klebsiella, Enterobacter, Citrobacter) can also cause UTIs

Urethritis Disease

• Inflammatory response
• Painful urination, cloudy/pink (bloody) urine.
• Can lead to cystitis and nephritis (ascending infection).

Epidemiology of E. coli UTI

• The most common cause of UTIs is E. coli.
• Most UTIs are community-acquired.
• Nosocomial infections account for a significant number of UTIs (hospital setting).
• Catheterization is also a significant factor (hospital setting).

Diagnosis of E. coli UTI

• Standard urine culture.
• Gram negative.
• Lactose-fermenter

Treatment of E. coli UTI

• Antibiotic resistance is common, so susceptibility testing is important.
• Treatment with appropriate antibiotics.

Urethritis due to Enterococci

• Enterococcus species are opportunistic pathogens frequently causing UTIs.
• The second most common cause of UTIs.
• 10% of all UTIs, 16% nosocomial UTIs, are often Enterococcal infections.

Diagnosis of UTI due to Enterococci

• Culture on blood and MacConkey agar.
• Gamma-hemolytic and catalase positive.
• Lancefield Group D.
• Enterococci do not produce nitrate reductase.

Other Species causing Urethritis

• Klebisella sp.
• Staphylococcus aureus
• Other Staphylococcus sp
• Proteus sp
• Enterobacter sp
• Pseudomonas sp

Cystitis

• 95% of cases are E. coli infections in females.
• Symptoms include painful urgent urination (dysuria).
• Common in women due to anatomical factors (short urethra, proximity to anus, sexual intercourse).
• Poor hygiene is a significant factor.

Treatment of Cystitis

• Trimethoprim/sulfamethoxazole (TMP/SMX), quinolones, and ampicillin.

Pyelonephritis

• E. coli infection (75%).
• Symptoms include fever, back pain, and potentially impaired kidney function.
• Scar tissue can lead to permanent kidney damage.
• Can spread to the blood.

Diagnosis of Pyelonephritis

• A supra-pubic aspirate can be collected from the bladder.

Treatment of Pyelonephritis

• Administration of antibiotics.
• 2/3-generation cephalosporins are often used.

Leptospirosis

• Leptospira interrogans.
• Spirochete bacteria; usually found in animal urine.
• An obligatory aerobe- needs oxygen to survive & replicate
• Zoonotic infection (spread from animals to humans).

Leptospirosis Disease

• Typically asymptomatic
• Phase 1 (Leptospiremic): Sudden high fever, headache, muscle aches, and chills.
• Phase 2 (Immune or Weil's Disease): kidney, liver, and other organ damage.
• Mortality (5-15%)

Epidemiology of Leptospirosis

• Animal urine in soil & water.
• Enters through a wound or abrasion- such as a cut or scrape on the skin.
• Risk to those who deal with or are in close contact with animals or water (e.g., farmers, those who swim or work around contaminated water).

Diagnosis of Leptospirosis

• Isolating pathogen from blood and CSF (cerebrospinal fluid)

Prevention of Leptospirosis

• Vaccination may be offered to people at high risk for exposure.
• Avoid water with animal contact.
• Clean wounds promptly and thoroughly.

Reproductive System Barriers

•  Ciliated epithelial cells
• Mucus Membranes
• Mucus + IgA
• Vaginal pH (low in women)
• Normal flora (many in women; mostly skin flora in men)

Diseases of the Genital Tract (STDs)

• Infectious agents increase fluid discharge in the male and female reproductive tract.
• Transmission of pathogens through genital fluids.
• Genital ulcer diseases may result in lesions.
• Infections can increase chance of HIV exposure due to open lesions.

Gonorrheal Urethritis

• Neisseria gonorrhoeae (gonococcus) is a gram-negative diplococci (in pairs) pyogenic (pus-forming) coccus.
• Diagnostic indicator: Gonococci in pairs with neutrophils.

Gonococcal Disease

• Sexually transmitted disease (STD).
• Purulent (pus) discharge
• Symptoms in females can include abnormal bleeding & pain.
• Many women are asymptomatic.
• Male symptoms: painful urination and discharge (pus).
• Untreated, leads to Pelvic Inflammatory Disease (PID) in women.

Pelvic Inflammatory Disease (PID)

• Infection of the pelvic organs (uterus, fallopian tubes, and ovaries) frequently linked to STDs.
• The infection can cause damage, including scarring preventing eggs from traveling and contributing to ectopic pregnancies.

Pharyngeal/Anal Gonorrhea, or Gonococcal Sepsis

• Pharyngeal (throat) or anal infections are extremely rare.
• Associated with systemic infections like arthritis, endocarditis, and meningitis.

Gonorrhea Virulence Factors

• Phase Variation: bacteria can turn genes coding for fimbrial proteins on & off according to the bacterium's circumstance.

Gonorrhea Diagnosis

• Gram stain: Gram-negative intracellular diplococci.
• Culture- fastidious bacterial strains require 5% CO2 incubation, Modified Thayer Martin agar plus antibiotics to inhibit normal flora.
• Other tests:
• DNA probe, or ELISA

Gonorrhea Treatment

• Floroquinolones (1 dose) or Ciprofloxacin/Ofloxacin.

Chlamydia trachomatis

• Obligate intracellular bacteria; complex life cycle.
• Has two forms: Elementary Body (EB)- infectious; Reticulate Body (RB)- noninfectious but metabolically active

Chlamydial Disease

• Urethritis (NOW most common bacterial STD in the U.S., now most common)
• Frequent coinfection.
• Asymptomatic (75%) in men & women
• often a clear discharge rather than purulent.
• No pus (neutrophil influx)
• Little pain or irritation.
• Pelvic Inflammatory Disease (PID) frequently in women
• Epididymitis frequently in men.

Chlamydia Epidemiology

• Sexual contact.
• Asymptomatic carriers spread infection.
• Infections cause increased HIV incidence.
• Recruitment of CD4 lymphs.
• Increased HIV targets.

Chlamydia Diagnosis

• DFA (Direct Fluorescent Antibody), Direct ELISA
• PCR (Polymerase Chain Reaction).
• If positive, screen for gonorrhea.

Chlamydia Treatment

• Doxycycline, Cefoxitin.

Ophthalmia neonatorum

• Eye infection in newborns.
• Transmission during birth via infected birth canal frequently with gonorrhea or chlamydia.

Syphilis

• Treponema pallidum (spirochete) – gram-negative; cannot be cultured
• Elicits little immune response.

Primary Syphilis

• Chancre (lesion)
• Fluid from the sore is infectious.
• Females often unaware (chancre inside cervix).
• Organisms replicate and disseminate to other organs via blood.

Secondary Syphilis

• Skin rash- infectious.
• Hair loss, malaise, mild fever.
• Heals in weeks or months.

Latent Syphilis

• Symptoms latent (absent) for years.
• Bacteria continue to spread to various body systems.

Tertiary Syphilis

• Can begin following years or decades of a latent period.
• Gummas, a granuloma-like lesion, form on skin and organs, causing severe organ damage.
• Cardiovascular complications are possible.
• Neurological complications.
• Death outcome

Congenital Syphilis

• Placental transfer can occur during pregnancy.
• Untreated infections can be very severe or deadly.
• May affect newborn’s development and organ function.

Epidemiology of Syphilis

• Sexual contact.
• Low transmission rates in some populations.
• Incidence has increased in other populations.

Syphilis Diagnosis

• Screening tests:
• Rapid Plasma Reagin (RPR) test.
• Venereal Disease Research Laboratory (VDRL).
• Antigen latex test
• Confirmatory tests:
• FTA-abs (fluorescent treponemal antibody-absorbed).

Syphilis Treatment

• Penicillin (Benzylpenicillin)- commonly administered long-acting penicillin injection, Doxycycline, or Tetracycline.

Soft Chancre

• Haemophilus ducreyi (small gram-negative rods; facultative anaerobe)
• Symptoms: Develop into papules, become pustules, ulcerate into larger lesions
• Lymphadenitis (buboes).

Soft Chancre Epidemiology

• Important in Asia, Africa, and Latin America; less common in the U.S.
• Chancres facilitate HIV transmission.

Diagnosis of Soft Chancre

• Culture on chocolate agar (fastidious).
• PCR for H. ducreyi, Treponema pallidum (syphilis) - or HSV1/2

Soft Chancre Treatment

• Erythromycin is used in the US due to resistance differences.
• Treatment determined by susceptibility testing

Bacterial Vaginosis (BV)

• Gardnerella vaginalis (an anaerobe; small pleomorphic gram-negative bacilli; common normal vaginal flora).

G. vaginalis Disease

• Malodorous discharge ("fishy odor"), itching.
• No vaginal epithelium inflammation
• Superinfection occurs due to pH changes or balance of normal flora disruption.
• Low birth weights in infants born to mothers with BV during pregnancy.

G. vaginalis Diagnosis

• Clue cells (diagnostic)
• Anaerobic culture

G. vaginalis Treatment

• Re-establish low vaginal pH (higher pH kills Lactobacillus)
• Metronidazole.

Human Immunodeficiency Virus (HIV)

• Retrovirus, Reverse transcriptase (RNA-DNA-Protein).
• Similar to Simian Immunodeficiency Virus (SIV) mutated from a zoonotic virus.
• Primarily an STD.
• HIV-1 and HIV-2 have been identified

Genital Herpes

• Herpes Simplex Virus (HSV) is usually subclinical and doesn't present with lesions during the primary infection.
• All subsequent outbreaks = genital lesions.
• Vesicular lesions
• Macrophages and lymphocytes are the main host cells
• Burning sensation
• latent infection- recurrences
• Virus over time in dorsal root ganglia.
• Chronic herpes may develop Encephalitis in some individuals
• Mortality rate 70% without treatment: but Acyclovir is good treatment.
• Neonatal herpes- crosses placental barrier and causes problems.

Herpes Epidemiology-

• Direct sexual contact
• 42 million infected in the U.S.
• 20% of genral population seropsoitive
• 500,000 new cases per year

Herpes Diagnosis

• Seeing lesions
• Serology
• PCR
• Virus culture

Herpes Treatment

• Acyclovir •Famiciclovir, Valcyclovir

Genital Warts (HPV)

• Human Papillomavirus (HPV) is over 100 serotypes
• A few strains are linked to cancers (Cervical, penile, anal, oropharyngeal cancer).
• HPV is the most common viral STI in the U.S.

HPV Disease

• Warts = Hyperplasia (finger-like projections).
• Prickle cells are infected & transformed.
• Majority of infections self-limiting
• Malignant cancers occur in some infected individuals. (Malignancy is infrequent).
• Cervical cancer is common: caused by HPV types 16 and 18.

HPV Epidemiology

• Sexually transmitted disease.
• 1 million new cases per year
• 70% Cervical cancer cases associated with HPV 16 and/or 18.
• Other high risk types (31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68).
• Intermediate risk (HPV 31, 33, 35).
• Low risk (HPV 6, 11 - most genital warts, 42, 43, 44)

HPV Diagnosis

• Serological typing.
• Pap smear
• Looking for nucleic acid of cancer-causing HPV.

HPV Treatment

• Imiquimod (Aldara) induces interferon
• Vaccination against cancer-causing strains and genital warts. • HPV types 6, 11, 16 and 18

Candidiasis (Yeast Infection)

• Candida albicans (a yeast, a dimorphic fungus).
• Thick, white, and cheesy discharge.
• Vulvovaginal candidiasis (VVC) or oral candidiasis (thrush).
• Frequently observed during pregnancy
• Often an opportunistic infection secondary to antimicrobial use.

Candidiasis Epidemiology

• Occurring in up to 75% of women.
• Contributed to by oral contraceptives and pregnancy, due to elevated glycogen levels in vaginal secretions.

Candidiasis Diagnosis

• Microscopic identification of yeast
• Germ tube tests.

Candidiasis Treatment

• Miconazole, clotrimazole (OTC).
• Prescription oral medication- Flucanozole.

Trichomoniasis

• Trichomonas vaginalis (anaerobic, flagellated protozoon).

Trichomoniasis Disease

• Itching (dysuria)
• Profuse green/yellow discharge.
• Foul-smelling, frothy discharge

Trichomoniasis Epidemiology

• 50% of infected cases are asymptomatic (in men).
• Need direct sexual contact.

Trichomoniasis Diagnosis

• Microscopic analysis (routine urine analysis); dysuria = frequent urination with painful sensation during passing urine.
• Undulating membrane, jerky motility.
• Direct ELISA.
• DNA probes

Trichomoniasis Treatment

• Metronidazole.

Diseases of the Digestive Tract

• Structures of the mouth.
• Normal flora of the mouth.
• Bacterial infections of the mouth.
• Gram stain results.
• Diseases.
• Epidemiology.
• Virulence factors.
• Key characteristics.

Dental Caries (Cavities)

• Key culprits: Streptococcus mutans, Streptococcus sobrinus, Scardovia wiggsiae
• Nursing bottle caries; early in childhood

Oral Micro-bial Community

• Saliva leaves protein on teeth to which normal flora (NF) adhere.
• NF make sticky polymers (like glucans or fructans).
• Secondary colonizers ferment sucrose resulting in acid production (leaches calcium from tooth enamel).
• Introduction of sugars can result in dentin breakdown.

Treatment of Caries

• Brushing and flossing.
• Alternative carbohydrates.
• Natural defenses: saliva-lysozyme, crevicular fluid, flushing, and phagocytic cells.
• Good dental hygiene practice.

Periodontal Disease

• Inflammation and degeneration of structures that support teeth (gums and bone).
• Gingivitis (gum infection) occurs frequently, due to swelling, redness, and bleeding.
• Usually caused by anaerobes.

Acute Necrotizing Ulcerative Gingivitis (ANUG)

• Tissue damage due to an inflammatory response.
• Synergistic infection.
• Treponema vincentii, Prevotella intermedia, and Fusobacterium species (anaerobes).
• Causes rapid advancement into periodontal tissues.
• Symptoms: severe pain, bleeding, pseudomembrane formation and necrosis.
• Treatment: Debridement, oxidizing agents, and metronidazole for anaerobes.

Digestive Tract Defenses

• Mucus, secretory IgA, peristalsis, saliva (high acid), bile
• GALT, tonsils, adenoids, lymphoid tissue in esophagus, Peyer's patches, M cells, appendix, microbial antagonism.

The Digestive System

• Stomach, small intestine(Duodenum, Jejunum, Ileum), Normal Flora of the stomach and small intestines (Few microorganisms, High acid, Rapid food movements, Essentially no normal flora), Large intestine (Colon; 100 million organisms/ gram feces; 40% fecal mass, Multiple species, Almost all anaerobes) • Identifying stool pathogens is very difficult due to multiple species being mixed within the sample

Most common isolates in stool normal flora

• Facultative Gram-negative rods • E. coli, Proteus, Citrobacter, Enterobacter, Klebsiella • Gram-positive cocci • Enterococci (No growth on MacConkey.)

Selective and Differential Media in Stool Cultures

• Hecktoen- Enteric agar, MacConkey agar, Campylobacter agar , MacConkey sorbitol • Pathogens are non-lactose fermenters (can distinguish Salmonella from Shigellea.) • Normal flora are lactose fermenters. • Certain pathogens need special incubation conditions.

Terms to describe GI tract infections

• Diarrhea, dysentery, gastroenteritis, enterocolitis

Bacterial Diseases of the Digestive Tract

• Food intoxication (toxins cause symptoms. QUICK ONSET, typically 3-6 hours.)
• Food infection (organisms cause symptoms, usually 24-48 hours.)

Staphylococcal Food Poisoning

• Staphylococcus aureus; Enterotoxin-producing strains; Phage genes code for toxin; Superantigen.
• Symptoms are associated with a strong immune response.
• Usually self-limiting 24 hours

Foods at risk for Staph Food Poisoning

• Cream-filled products, dairy, salads (esp. with mayo), ham, meat, and meat products
• Bacteria can survive on food handler hands, nose, and skin; stable to heat/boiling

Staph Toxemia Diseases

• Toxemia
• Onset is quick: 3-6 hours
• Nausea and vomiting
• Emetic toxin- vomiting agent
• Diarrhea, chills
• Self-limiting: 24 hours

Staph Enterotoxin Virulence Factors

• 5 distinct enterotoxins commonly identified.
• SEA, SEB, SEC, SED, SEE are frequently seen

Staph Intoxication Diagnosis

• No detectible organism in food or stool, so the Staph enterotoxin must be tested
• Stool culture (if organism).
• Beta-hemolytic Golden Colored
• Catalase +, Coagulase +

Staph Food Poisoning Treatment

• Remove food
• Treat the carrier
• Often antibiotics are not helpful
• Prevention: Proper food handling and refrigeration, control of infected food handlers.

AAD (Antibiotic-Associated Diarrhea)

• Clostridium difficile (an anaerobe, gram-positive spore-former).
• Opportunistic pathogen that is usually in low numbers in the gut, but can proliferate in the bowel following antibacterial treatment (superinfection).

AAD Disease

• Disrupts normal gut flora causing pseudomembranous colitis
• Nearly 100% due to C. difficile
• Symptoms include severe diarrhea, bowel obstruction, and rarely death.
• Often nosocomial (hospital setting).

AAD Virulence Factors

• Toxin A – diarrhea
• Toxin B – cytotoxin, destroys cells
• Substance that inhibits bowel motility.

AAD Diagnosis

• Anaerobic Culture
• ELISA for Toxin A & B

AAD Treatment

• Antibiotics (metronizadole) for anaerobes.

Bacillus cereus Food Poisoning

• Bacillus cereus (gram-positive rod spore-former).
• Caused by two different toxins, linked to meat and vegetables; linked to rice
• Quick onset (typically within 6 hours), self-limiting.
• May cause either diarrhea or nausea & vomiting.

Clostridium perfringens Food Poisoning

• Clostridium perfringens (gram-positive rod spore-former).
• Enterotoxin (associated with sporulation); Quick onset (self-limiting, 2-3 days).
• Spores contaminate meat.
• Problems only due to canning industry defects; toxin is polypeptide.
• Spores often survive food processing, resulting in toxin production during subsequent growth within the food if the food is undercooked.

Vibrio cholerae Food Poisoning

• Vibrio cholerae (gram-negative, curved rod).
• Cholera toxin.
• Causes severe watery diarrhea (1 liter/hour) and vomiting, but fatality rate has lessened with medical interventions.
• Requires higher bacterial inoculum (1x10^8 bacteria.)
• Can colonize crustaceans and seafood

Cholera Epidemiology

• Commonly seen in Southern U.S. and requires a high inoculum.
• Often found in brackish water.
• Commonly found in food at restaurants (like sushi).

Cholera Toxin Virulence Factor

• A-B subunit toxin
• A subunit is the enzymatic active portion that ADP-ribosylates the host’s cellular protein, then changes intestinal cells into water-secreting cells: causing extreme water loss.
• B subunit binds to the target cells.

Cholera Diagnosis

• Characteristics of rice water stools.
• Culture. (Detection of bacterial strains in the culture.)

Cholera Treatment

• Fluid replacement therapy (oral rehydration).
• Antibiotics (tetracycline)

Shigella Species

• Shigella dysenteriae (gram-negative rod), uncommon in the US; international disease.
• Severe bloody diarrhea. Rapid onset, and self-limiting course (3-5 days)
• Toxins: heat-labile exotoxin, enterotoxin, endotoxin (LPS).

Salmonella Infection

• Salmonella Enterica serotype (not Typhi) is a gram-negative rod, intracellular, and has 2000 serovars linked to animal infections.
• Common symptoms include fever, abdominal cramps, and diarrhea.
• Onset can occur 12-36 hours before symptoms, lasting 3-5 days
• Bacteremia (occasional septicemia): bacteria entering the blood. May be shed for 6 months.

Salmonella Enterica Epidemiology

• Contamination in various raw meats and eggs.
• Inadequate heating during processing can allow bacteria to survive.

Salmonella Enterica Virulence Factors

• Intracellular life
• Attachment to cells.
• Serotypes infect specific animals.

Salmonella Enterica Diagnosis

• Culture using non-lactose-fermenting media (NLF) requiring MacConkey & Hektoen-Enteric agar.
• Serotyping (by O antigen).
• Susceptibility testing.

Pathogenic strains of Escherichia coli

• Lactose fermenters; magenta-pink on lactose-MacConkey agar, orange-salmon on Hektoen-Enteric agar.
• Includes strains EPEC, EIEC, EHEC, & ETEC.

Enteropathogenic E. coli (EPEC)

• Infantile diarrhea—mild chronic disease
• No toxins; intimately associated with the gut epithelium

Enteroinvasive strains (EIEC)

• Contaminated food/water, in poor hygiene areas
• Severely invades intestinal tissue; blood and mucus in the stool
• Increased symptom severity (e.g. more severe than EPEC).

Enterohemorrhagic strains (EHEC)

• Serious outbreaks frequently associated with shigella-like disease.
• Produces Shiga toxin, a non-invasive toxin
• O157:H7 strain.
• Destroys epithelial lining (intimin).
• Delivers Shiga toxin.
• Hemolytic Uremic Syndrome (HUS; acute kidney failure)

How to Identify EHEC

• Looks like normal flora E. coli.
• Use special MacConkey sorbitol plate.
• O157:H7 = Sorbitol Non-fermenter.

Hemolytic Uremic Syndrome

• Inflammation of the colon (often preceding hemorrhagic colitis)
• Kidney damage; destroys kidney function.

Enterotoxigenic E. coli (ETEC)

• Cholera-like diseases, particularly common in travelers
• Non-invasive cholera toxin.

Campylobacter Gastroenteritis

• Campylobacter jejuni (curved gram-negative rods)
• Microaerophilic (requires low oxygen concentrations for respiration).
• Optimal temperature = 42°C.

Campylobacter Disease

• Inflammatory bowel disease (e.g., gastroenteritis).
• Abdominal pain, diarrhea, and dysentery.
• Fever; Recovery in 1 week; can last months.

Campylobacter Epidemiology

• Most common bacterial cause of gastroenteritis in people (U.S.).
• 2 million cases yearly
• Animals & humans, specifically poultry and cattle
• Via feces in milk or environment

Guillain-Barre Syndrome

• 20-40% incidence rate; temporary acute paralysis
• Surface molecule of bacteria resembles nerve tissue lipid causing an autoimmune attack.
• Possible death.

Campylobacter Diagnosis

• Blood agar plus antibiotics to inhibit normal flora, incubate at 42°C.
• Look for growth.
• Part of routine stool culture.

Yersiniosis

• Yersinia enterocolitica (gram-negative intracellular bacteria; grows at 4°C).
• Diarrhea, fever, and headache are common.
• Frequently misdiagnosed as appendicitis.

Helicobacter pylori

• Curved gram-negative rod; potent urease enzyme.
• Bacteria attach to stomach lining causing inflammation.
• Chronic inflammatory disease (ulcers), some links to stomach cancer.

Helicobacter pylori Epidemiology

• Common infection (30-50% of world population).
• Can contribute to gastric & duodenal ulcers (15-20%).
• Individuals with Type O blood type are more susceptible to its effects.
• Emotional stress may also contribute to infection

Helicobacter pylori Treatment

• Antibiotics
• Bismuth (Pepto-Bismol) to halt ulceration; ulcers need to heal afterward.

Helicobacter pylori Diagnosis

• Endoscopy (stomach biopsy-staining)

Listeria monocytogenes

• Foodborne transmission (commonly in ground beef; chicken & turkey carcasses, lunch meat, hot dogs, and unpasteurized dairy).
• Grows well in refrigerators.
• Infection of the fetus.
• Organism crosses the placenta causing a congenital infection of the fetus involving meningitis

Viral Causes of Digestive Diseases

• Mumps, • Rotavirus, • Norovirus, • Hepatitis A, • Hepatitis B, • Hepatitis C, • Hepatitis D (co-infections with HBV), Hepatitis E (HEV), Hepatitis F (HFV), Hepatitis G (HGV).

Parasitic Causes of Digestive Diseases

• Common helminths (worms), such as Ascaris lumbricoides, Necator americanus (hookworm), Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm), Diphyllobothrium latum (fish tapeworm/fish worm).
• Symptoms can sometimes be subtle- few physical symptoms.
• Sometimes eggs or parasite segments are found in stool, blood tests may show elevated eosinophils (a type of white blood cell).
• Treatment can involve anti-helminthic drugs.

Respiratory Tract Review

• Barriers to infection • Normal flora of the lower respiratory tract • Bacterial causes of lower respiratory tract infections • Gram stain result • Epidemiology • Virulence factors • Viral causes of LRT disease and descriptions • Fungal causes of LRT disease

Test your knowledge of urinary tract infections, whooping cough, and influenza. This quiz covers symptoms, epidemiology, and characteristics of various infectious agents. Perfect for students studying microbiology or health sciences!