Shaping The Future — Microbial Diseases (Nervous System, Reproductive Tract, Skin)

A comprehensive set of Q&A flashcards covering nervous system infections, sepsis, reproductive tract infections, and skin/mkin infections based on the lecture notes.

What are the three main components of the nervous system?

Brain, spinal cord, and a network of nerves throughout the body.

What are the two subdivisions of the nervous system?

Central nervous system (CNS) and Peripheral nervous system (PNS).

What are the meninges of the CNS and their order from outer to inner?

Dura mater (outer), arachnoid membrane (middle), pia mater (inner).

What space lies between the arachnoid and pia mater and what fills it?

Subarachnoid space, filled with cerebrospinal fluid (CSF).

What is the CSF composition?

Water, proteins, glucose, sodium, and chloride.

What are the main functions of CSF?

Protects the brain & spinal cord, supplies nutrition, and circulates waste.

How can CSF samples be collected?

Lumbar puncture (LP) and ventricular tap (rare).

List four routes by which microorganisms can enter the nervous system.

Skull or backbone fractures, medical procedures, along peripheral nerves, and via blood or lymph.

What is meningitis?

Inflammatory response to infection of the meninges; bacterial meningitis is usually more serious than viral.

What is encephalitis?

Swelling of the brain usually caused by a viral infection.

What is Kernig’s sign a sign of?

Meningeal irritation; a positive Kernig’s sign.

Name common initial symptoms of bacterial meningitis.

Fever, severe headache, stiff neck; may also include nausea, vomiting, seizures, and coma.

For CSF laboratory analysis, how many sterile bottles are used and which bottle is reserved for bacteriology?

Three bottles (1, 2, 3); bottle 3 is used for bacteriological examination to avoid contamination.

List the CSF laboratory procedures used for diagnosis.

Visual appearance, microscopy (cell counts, Gram stain, Ziehl-Neelsen), negative staining, wet prep, culture, biochemical analysis, antigen/antibody detection tests.

What are common methods to detect pathogens in CSF?

Culture, Gram stain, Ziehl-Neelsen stain, negative staining, wet prep, antigen/antibody tests, and PCR for nucleic acids.

Which vaccines help prevent meningitis caused by certain pathogens?

Hib vaccine (Haemophilus influenzae type b), pneumococcal vaccines PCV13/PPSV23, meningococcal vaccines.

Haemophilus influenzae meningitis characteristics and risk group.

Gram-negative aerobic bacteria; Type b capsule; primarily affects children 6 months–4 years; Hib vaccine prevents it.

Neisseria meningitidis meningitis features and transmission.

Gram-negative diplococci; transmitted via respiratory droplets; nasopharyngeal carriers; prevented by meningococcal vaccines.

Streptococcus pneumoniae meningitis features?

Gram-positive diplococci; a common cause of meningitis and pneumonia; vaccination with PCV13/PPSV23 helps prevent.

Listeria monocytogenes meningitis risk groups and transmission.

Foodborne; affects pregnant women, elderly, and immunocompromised individuals.

Tetanus toxin mechanism?

Tetanospasmin blocks the relaxation pathway in muscles, causing sustained contractions.

Botulism toxin mechanism?

Botulinum toxin blocks acetylcholine release at neuromuscular junctions, causing flaccid paralysis.

Rabies transmission and pathogenesis?

Transmitted by bite of an infected animal; virus travels from muscle to CNS causing encephalitis.

Rabies prophylaxis options?

Pre-exposure vaccine (HDCV); Post-exposure vaccination plus rabies immune globulin (RIG).

Arboviral encephalitis prevention?

Vector control and vaccines for some arboviruses (e.g., Japanese encephalitis virus).

Cryptococcus neoformans meningitis risk and treatment.

Fungal meningitis; common in immunocompromised; inhaled and disseminates to CNS; mortality ~30% untreated; treatment includes amphotericin B and flucytosine.

African trypanosomiasis (sleeping sickness) causative agent and transmission.

Trypanosoma brucei gambiense and rhodesiense; transmitted by the tsetse fly.

Naegleria fowleri entry route?

Infection via the nasal passage during swimming; causes primary amebic meningoencephalitis (PAM).

Transmissible Spongiform Encephalopathies (TSEs) cause and transmission?

Prion diseases; misfolded proteins; can be transmitted via contaminated meat, transplantation, or inherited; examples include scrapie, CJD, Kuru, BSE.

What is sepsis?

A whole-body inflammatory state associated with infection; diagnosed when infection is present with two or more criteria (e.g., abnormal temperature, tachycardia, tachypnea, abnormal WBC).

Bacteremia vs septicemia difference?

Bacteremia is the presence of viable bacteria in the bloodstream; septicemia is when bacteria multiply and produce toxins, potentially life-threatening.

Pathophysiology of sepsis?

Endotoxin (LPS) or Gram-positive components trigger CD14/Toll-like receptor signaling; macrophages release TNF-α and IL-1; prostaglandins, tissue factor; coagulation cascade activation.

Blood culture collection guidelines?

Adults: 10–20 mL per culture bottle; children: 1–4 mL; collect from two separate venipuncture sites; obtain before starting antibiotics.

Blood culture media types?

Aerobic vials (enriched TSB, SPS, resins, O2), Anaerobic vials (plus CO2/N2), Pediatric vials, and Myco/F Lytic vials for fungi/mycobacteria.

Types of blood culture systems?

Conventional, Semiautomatic (BACTEC), and Automatic (BacT/Alert).

Common contaminants in blood cultures?

Coagulase-negative staphylococci (CONS), Bacillus spp., Corynebacterium spp., Propionibacterium acnes; Bacillus anthracis must be ruled out.

Normal skin microbiota?

Staphylococcus epidermidis, Propionibacterium acnes, Micrococci, and Yeasts.

Exanthem vs Enanthem?

Exanthem is a skin rash; Enanthem is a rash on mucous membranes (e.g., mouth, throat).

Common skin lesion terms?

Vesicle (small blister), Bulla (large blister), Macule (color change without elevation), Papule (raised spot).

Staphylococcal skin infections and toxins?

Staph epidermidis and Staph aureus; toxins include leukocidin and exfoliative toxin; cause impetigo, scalded skin syndrome, toxic shock syndrome.

Impetigo and scalded skin syndrome etiologies?

Often caused by Staphylococcus aureus and/or Streptococcus pyogenes.

GAS virulence factor?

M proteins are a major virulence factor of Streptococcus pyogenes.

Invasive GAS infections?

Cellulitis and Necrotizing Fasciitis; require prompt surgical and aggressive antibiotic therapy.

Pseudomonas skin infections?

Pseudomonas aeruginosa; produces pyocyanin (blue-green pigment); dermatitis, otitis externa, post-burn infections.

Wound infections common causes?

Pasteurella multocida (animal bites), Bartonella henselae (cat scratch disease), MRSA, VRE and anaerobes.

Lab diagnosis of wound infections?

Specimens (swabs, pus, fluids, skin scrapes); Gram stain; culture on blood agar (aerobic/anaerobic), chocolate agar (CO2), MacConkey/CLED; Sabouraud for fungi.

Acne pathogenesis and treatment?

Propionibacterium acnes involvement; treatments include isotretinoin, antibiotics, benzoyl peroxide, blue light therapy.

HPV and genital warts?

Genital warts are caused by Human Papillomaviruses (HPV); vaccines exist for certain strains.

Measles key features and vaccine?

Measles: macular rash and Koplik's spots; vaccine available and highly effective.

Rubella risks and vaccine?

Rubella ('German measles') can cause congenital rubella syndrome; prevented by the MMR vaccine.

Varicella Zoster virus characteristics?

Causes chickenpox and shingles; latency in dorsal root ganglia; reactivation causes shingles.

Smallpox and Monkeypox?

Smallpox eradicated; vaccines can provide cross-protection against monkeypox; vaccines and public health measures important.

Trichomonas vaginalis infection?

Trichomoniasis; transmitted sexually; diagnosed by microscopy, culture, or stained smear; treated with metronidazole.

Candidiasis overview?

Caused by Candida albicans; can affect mouth (thrush), genital tract, skin, and invasive infections; treated with azoles (e.g., fluconazole) or topical antifungals.

Bacterial vaginosis (BV)?

Gardnerella vaginalis and anaerobes; 'fishy' discharge; clue cells; treated with metronidazole.

Gonorrhea?

Neisseria gonorrhoeae; often asymptomatic in females, painful urination/discharge in males; diagnosis via Gram-negative intracellular diplococci and Thayer-Martin culture; treatment with ceftriaxone.

Nongonococcal urethritis (NGU) etiologies?

Chlamydia trachomatis, Mycoplasma hominis, and Ureaplasma urealyticum; treated with appropriate antibiotics.

Lymphogranuloma venereum (LGV) cause and treatment?

Chlamydia trachomatis serotypes L1-L3; treated with doxycycline.

Syphilis diagnosis and treatment?

Treponema pallidum; diagnosed by direct methods (darkfield) or serology (VDRL/RPR, ELISA, FTA-ABS, TPHA); treated with penicillin.

Genital herpes—agent and treatment?

Herpes simplex virus type 2 (HSV-2); treated with antivirals such as acyclovir, valacyclovir, or famciclovir.

Genital warts—cause and prevention?

HPV; vaccines available for some HPV strains.

Herpes zoster (VZV) characteristics?

Varicella-Zoster virus; latency in sensory nerves; reactivation causes shingles with localized painful rash.

Measles complications?

Encephalitis and, rarely, SSPE (subacute sclerosing panencephalitis).

Rubella congenital risk?

Congenital Rubella Syndrome can cause heart defects, deafness, and developmental issues.

Cutaneous mycoses pathogens?

Trichophyton, Epidermophyton, Microsporum; diagnosed by KOH mount and culture; treated with griseofulvin (oral) and topical antifungals.

Candida infections treatment options?

Antifungals such as fluconazole or topical azoles (e.g., clotrimazole) depending on site.

Scabies diagnosis and treatment?

Sarcoptes scabiei; diagnosed clinically or by skin scrapings; treated with topical permethrin or lindane.

What are the three main components of the nervous system?

Brain, spinal cord, and a network of nerves throughout the body.

What are the two subdivisions of the nervous system?

Central nervous system (CNS) and Peripheral nervous system (PNS).

What are the meninges of the CNS and their order from outer to inner?

Dura mater (outer), arachnoid membrane (middle), pia mater (inner).

What space lies between the arachnoid and pia mater and what fills it?

Subarachnoid space, filled with cerebrospinal fluid (CSF).

What is the CSF composition?

Water, proteins, glucose, sodium, and chloride.

What are the main functions of CSF?

Protects the brain & spinal cord, supplies nutrition, and circulates waste.

How can CSF samples be collected?

Lumbar puncture (LP) and ventricular tap (rare).

List four routes by which microorganisms can enter the nervous system.

Skull or backbone fractures, medical procedures, along peripheral nerves, and via blood or lymph.

What is meningitis?

Inflammatory response to infection of the meninges; bacterial meningitis is usually more serious than viral.

What is encephalitis?

Swelling of the brain usually caused by a viral infection.

What is Kernig’s sign a sign of?

Meningeal irritation; a positive Kernig’s sign.

Name common initial symptoms of bacterial meningitis.

Fever, severe headache, stiff neck; may also include nausea, vomiting, seizures, and coma.

For CSF laboratory analysis, how many sterile bottles are used and which bottle is reserved for bacteriology?

Three bottles (1, 2, 3); bottle 3 is used for bacteriological examination to avoid contamination.

List the CSF laboratory procedures used for diagnosis.

Visual appearance, microscopy (cell counts, Gram stain, Ziehl-Neelsen), negative staining, wet prep, culture, biochemical analysis, antigen/antibody detection tests.

What are common methods to detect pathogens in CSF?

Culture, Gram stain, Ziehl-Neelsen stain, negative staining, wet prep, antigen/antibody tests, and PCR for nucleic acids.

Which vaccines help prevent meningitis caused by certain pathogens?

Hib vaccine (Haemophilus influenzae type b), pneumococcal vaccines PCV13/PPSV23, meningococcal vaccines.

Haemophilus influenzae meningitis characteristics and risk group.

Gram-negative aerobic bacteria; Type b capsule; primarily affects children 6 months–4 years; Hib vaccine prevents it.

Neisseria meningitidis meningitis features and transmission.

Gram-negative diplococci; transmitted via respiratory droplets; nasopharyngeal carriers; prevented by meningococcal vaccines.

Streptococcus pneumoniae meningitis features?

Gram-positive diplococci; a common cause of meningitis and pneumonia; vaccination with PCV13/PPSV23 helps prevent.

Listeria monocytogenes meningitis risk groups and transmission.

Foodborne; affects pregnant women, elderly, and immunocompromised individuals.

Tetanus toxin mechanism?

Tetanospasmin blocks the relaxation pathway in muscles, causing sustained contractions.

Botulism toxin mechanism?

Botulinum toxin blocks acetylcholine release at neuromuscular junctions, causing flaccid paralysis.

Rabies transmission and pathogenesis?

Transmitted by bite of an infected animal; virus travels from muscle to CNS causing encephalitis.

Rabies prophylaxis options?

Pre-exposure vaccine (HDCV); Post-exposure vaccination plus rabies immune globulin (RIG).

Arboviral encephalitis prevention?

Vector control and vaccines for some arboviruses (e.g., Japanese encephalitis virus).

Cryptococcus neoformans meningitis risk and treatment.

Fungal meningitis; common in immunocompromised; inhaled and disseminates to CNS; mortality \~30% untreated; treatment includes amphotericin B and flucytosine.

African trypanosomiasis (sleeping sickness) causative agent and transmission.

Trypanosoma brucei gambiense and rhodesiense; transmitted by the tsetse fly.

Naegleria fowleri entry route?

Infection via the nasal passage during swimming; causes primary amebic meningoencephalitis (PAM).

Transmissible Spongiform Encephalopathies (TSEs) cause and transmission?

Prion diseases; misfolded proteins; can be transmitted via contaminated meat, transplantation, or inherited; examples include scrapie, CJD, Kuru, BSE.

What is sepsis?

A whole-body inflammatory state associated with infection; diagnosed when infection is present with two or more criteria (e.g., abnormal temperature, tachycardia, tachypnea, abnormal WBC).

Bacteremia vs septicemia difference?

Bacteremia is the presence of viable bacteria in the bloodstream; septicemia is when bacteria multiply and produce toxins, potentially life-threatening.

Pathophysiology of sepsis?

Endotoxin (LPS) or Gram-positive components trigger CD14/Toll-like receptor signaling; macrophages release TNF-α and IL-1; prostaglandins, tissue factor; coagulation cascade activation.

Blood culture collection guidelines?

Adults: 10–20 mL per culture bottle; children: 1–4 mL; collect from two separate venipuncture sites; obtain before starting antibiotics.