22 Key Pathogens: Diseases, Symptoms, and Prevention
Posted on Feb 11, 2025 in Microbiology
Salmonella enteritidis
- Genus/Species: Salmonella enteritidis
- Disease: Salmonellosis (food poisoning)
- Symptoms: Fever, stomach cramps, diarrhea
- Virulence Factors: Invades intestinal cells, produces enterotoxins
- Mechanism: Enterotoxins disrupt ion transport, causing diarrhea
- Treatment: Rehydration; Ciprofloxacin or Azithromycin in severe cases
- Prevention: Cook poultry thoroughly, practice good hand hygiene
- Break Chain: Destroy animal reservoirs, inspect food products
Geobacillus stearothermophilus
- Genus/Species: Geobacillus stearothermophilus
- Notes: Non-pathogenic; used as a sterilization indicator
Staphylococcus aureus
- Genus/Species: Staphylococcus aureus
- Diseases: Skin infections, pneumonia, food poisoning
- Symptoms: Boils, abscesses, vomiting, diarrhea, fever
- Virulence Factors: Protein A, alpha-toxin, biofilm formation
- Mechanism: Alpha-toxin lyses host cells; Protein A binds antibodies, evading phagocytosis
- Treatment: Methicillin (for non-resistant strains); Vancomycin (for MRSA)
- Prevention: Maintain good hygiene, practice proper wound care
- Break Chain: Quarantine carriers; enforce strict hand hygiene
Mycobacterium tuberculosis
- Genus/Species: Mycobacterium tuberculosis
- Disease: Tuberculosis (TB)
- Symptoms: Persistent cough, fever, weight loss
- Virulence Factors: Survives in macrophages, mycolic acid resists immune attack
- Mechanism: Inhibits phagosome-lysosome fusion, evades destruction
- Treatment: Multi-drug therapy (isoniazid, rifampin, pyrazinamide, ethambutol)
- Prevention: BCG vaccine, early detection and treatment
- Break Chain: Quarantine infected individuals, increase herd immunity
Influenza Virus
- Genus/Species: Influenzavirus A/B/C (e.g., H1N1)
- Disease: Influenza (flu)
- Symptoms: Fever, cough, sore throat, body aches
- Virulence Factors: Hemagglutinin (HA), Neuraminidase (NA)
- Mechanism: HA enables viral entry; NA facilitates virus release
- Treatment: Tamiflu (oseltamivir), Relenza (zanamivir)
- Prevention: Vaccination, practice good hygiene
- Break Chain: Stay home when sick, cover coughs and sneezes
Streptococcus mutans
- Genus/Species: Streptococcus mutans
- Disease: Dental caries (cavities)
- Symptoms: Tooth decay, pain
- Virulence Factors: Biofilm formation, lactic acid production
- Mechanism: Lactic acid erodes enamel, causing cavities
- Treatment: Removal of decayed material, fillings
- Prevention: Maintain good oral hygiene, limit sugar intake
- Break Chain: Regular dental care and check-ups
Vibrio cholerae
- Genus/Species: Vibrio cholerae
- Disease: Cholera
- Symptoms: Severe watery diarrhea, dehydration
- Virulence Factors: Cholera toxin
- Mechanism: Toxin ADP-ribosylates G proteins, increasing cAMP, disrupting ion transport
- Treatment: Oral rehydration, antibiotics (in severe cases)
- Prevention: Clean water supply, proper sanitation
- Break Chain: Public health campaigns, treat sewage effectively
Corynebacterium diphtheriae
- Genus/Species: Corynebacterium diphtheriae
- Disease: Diphtheria
- Symptoms: Nasal discharge, fever, pseudomembrane formation
- Virulence Factors: Diphtheria toxin inhibits protein synthesis
- Mechanism: Toxin halts host protein synthesis, causing cell death
- Treatment: Antitoxin, penicillin, erythromycin
- Prevention: DTaP vaccine
- Break Chain: Vaccination, quarantine carriers
Clostridium tetani
- Genus/Species: Clostridium tetani
- Disease: Tetanus
- Symptoms: Muscle stiffness, spasms, lockjaw
- Virulence Factors: Tetanospasmin toxin blocks inhibitory neurotransmitters
- Mechanism: Sustained muscle contractions
- Treatment: Antitoxin, wound care, metronidazole
- Prevention: DTaP vaccine
- Break Chain: Proper wound care, vaccination
Bordetella pertussis
- Genus/Species: Bordetella pertussis
- Disease: Whooping cough
- Symptoms: Severe coughing fits
- Virulence Factors: Pertussis toxin disrupts immune signaling
- Mechanism: Toxin increases cAMP, damaging immune cells
- Treatment: Erythromycin
- Prevention: DTaP vaccine
- Break Chain: Quarantine carriers, increase vaccination rates
Rubeola Virus
- Genus/Species: Measles morbillivirus
- Disease: Measles
- Symptoms: Fever, cough, rash; complications can include pneumonia and encephalitis
- Virulence Factors: Fusion proteins enable virus-cell fusion
- Mechanism: Targets dendritic and T cells, suppresses immunity
- Treatment: Supportive care (hydration, fever management)
- Prevention: MMR vaccine
- Break Chain: Quarantine, vaccination programs
Mumps Virus
- Genus/Species: Mumps orthorubulavirus
- Disease: Mumps
- Symptoms: Salivary gland swelling, fever, muscle aches
- Virulence Factors: Immune evasion
- Mechanism: Infects glandular epithelial cells, causing inflammation
- Treatment: Supportive care (rest, hydration)
- Prevention: MMR vaccine
- Break Chain: Vaccination, isolate cases
Borrelia burgdorferi
- Genus/Species: Borrelia burgdorferi
- Disease: Lyme disease
- Symptoms: Bullseye rash, joint pain, neurological issues
- Virulence Factors: Outer surface protein variation
- Mechanism: Evades immunity via antigenic variation
- Treatment: Antibiotics (doxycycline, amoxicillin)
- Prevention: Avoid tick bites, use tick repellents
- Break Chain: Control tick populations, public education
Helicobacter pylori
- Genus/Species: Helicobacter pylori
- Disease: Gastritis, peptic ulcers
- Symptoms: Abdominal pain, bloating, nausea
- Virulence Factors: Urease enzyme, adhesins
- Mechanism: Urease neutralizes stomach acid, adhesins enable colonization
- Treatment: Triple therapy: Amoxicillin, clarithromycin, proton pump inhibitor
- Prevention: Practice food safety and good hygiene
- Break Chain: Sanitation, education on proper food handling
Clostridium perfringens
- Genus/Species: Clostridium perfringens
- Disease: Gas gangrene, food poisoning
- Symptoms: Tissue necrosis, diarrhea (in cases of food poisoning)
- Virulence Factors: Alpha-toxin, gas production in tissues
- Mechanism: Alpha-toxin disrupts cell membranes, immune response
- Treatment: Antibiotics, surgical debridement (for gas gangrene); supportive care (for food poisoning)
- Prevention: Proper wound care, proper food handling
- Break Chain: Sanitation, wound management
Mycobacterium leprae
- Genus/Species: Mycobacterium leprae
- Disease: Leprosy (Hansen’s disease)
- Symptoms: Skin lesions, nerve damage, loss of sensation
- Virulence Factors: Survives in macrophages, slow growth rate
- Mechanism: Evades immunity by residing in macrophages, causing chronic inflammation
- Treatment: Multidrug therapy (dapsone, rifampin, clofazimine)
- Prevention: Early detection, reduce disease reservoirs
- Break Chain: Quarantine infected individuals, early treatment
Chlamydia trachomatis
- Genus/Species: Chlamydia trachomatis
- Disease: Chlamydia (STI)
- Symptoms: Often asymptomatic; urethritis, cervicitis, pelvic inflammatory disease (PID)
- Virulence Factors: Intracellular survival, outer membrane proteins for attachment
- Mechanism: Enters cells via endocytosis, evades immune detection, damages cells
- Treatment: Azithromycin, doxycycline
- Prevention: Practice safe sex (e.g., condom use)
- Break Chain: Promote regular STI screening and education
Neisseria gonorrhoeae
- Genus/Species: Neisseria gonorrhoeae
- Disease: Gonorrhea (STI)
- Symptoms: Urethral discharge, painful urination (in men); asymptomatic or PID (in women)
- Virulence Factors: Pili for attachment, antigenic variation
- Mechanism: Pili enable adherence; antigenic variation prevents immune recognition
- Treatment: Combination therapy (ceftriaxone and azithromycin)
- Prevention: Practice safe sex, get tested for STIs
- Break Chain: Increase education, improve access to treatment
Treponema pallidum
- Genus/Species: Treponema pallidum
- Disease: Syphilis (STI)
- Symptoms: Chancre sores (primary), rash and fever (secondary), neurological damage (tertiary)
- Virulence Factors: Immune evasion, tissue invasion
- Mechanism: Disseminates through tissues, antigenic variation evades immunity
- Treatment: Penicillin (intramuscular injection)
- Prevention: Practice safe sex
- Break Chain: Promote STI education and access to treatment
Human Papillomavirus (HPV)
- Genus/Species: Papillomavirus (e.g., HPV 16, HPV 18)
- Disease: Genital warts, cervical and other cancers
- Symptoms: Genital warts, often asymptomatic in early cancer stages
- Virulence Factors: Integration into host DNA, oncoproteins E6/E7 inactivate p53 and Rb
- Mechanism: E6/E7 disrupt tumor suppression, causing malignancy
- Treatment: Topical treatments, cryotherapy (for warts); surgery, radiation, chemotherapy (for cancer)
- Prevention: HPV vaccination (e.g., Gardasil)
- Break Chain: Vaccination, practice safe sex
Herpes Simplex Virus Type 2 (HSV-2)
- Genus/Species: Human alphaherpesvirus 2
- Disease: Genital herpes
- Symptoms: Painful blisters/sores, fever, body aches
- Virulence Factors: Establishes latency in nerve cells
- Mechanism: Viral DNA persists in neurons, reactivates periodically
- Treatment: Antivirals (acyclovir, valacyclovir) reduce outbreaks
- Prevention: Practice safe sex, use condoms
- Break Chain: Increase awareness, improve access to antivirals
Human Immunodeficiency Virus (HIV)
- Genus/Species: Lentivirus (HIV-1, HIV-2)
- Disease: Acquired immunodeficiency syndrome (AIDS)
- Symptoms: Fever, fatigue, weight loss, opportunistic infections
- Virulence Factors: Targets CD4+ T cells, integrates into genome
- Mechanism: Infects/destroys CD4+ T cells, crippling immune function
- Treatment: Antiretroviral therapy (ART) suppresses replication
- Prevention: Practice safe sex, use PrEP, avoid needle sharing
- Break Chain: Promote testing and preventive education
Listeria monocytogenes
- Genus/Species: Listeria monocytogenes
- Disease: Listeriosis
- Symptoms: Fever, stiff neck, confusion, muscle aches
- Virulence Factors: Listeriolysin O (phagosome escape), intracellular motility (actin polymerization)
- Mechanism: Invades host cells, spreads intracellularly
- Treatment: Antibiotics (ampicillin, gentamicin)
- Prevention: Proper food handling, avoid unpasteurized dairy
- Break Chain: Enhance food safety measures
Prions
- Disease: Creutzfeldt-Jakob disease (CJD), variant CJD, mad cow disease
- Symptoms: Neurological decline, dementia, loss of coordination
- Virulence Factors: Misfolded proteins induce misfolding in normal prions
- Mechanism: Protein aggregates disrupt brain function
- Treatment: None currently effective
- Prevention: Avoid contaminated tissue; use stringent sterilization protocols
- Break Chain: Strict controls on tissue handling
