Gram-negative cocci Flashcards
Gram-negative cocci in pairs (some slightly elongated)
Causes upper respiratory tract infections, especially including otitis media and sinusitis in children (3rd most common cause)
Causes bronchitis or pneumonia in children and adults (in the top 3-4 of causes)
Moraxella catarrhalis
3rd most common cause of otitis media/sinusitis
Moraxella catarrhalis
Endotoxins
Resistance to complement
beta lactamase
moraxella catarrhalis
2 cause of meningitis
N. meningitis
1 cause of meningitis
S. pneumoniae
2 cause of meningitis, can cause secondary tissue necrosis (i.e., invasive)
Gram negative cocci in pairs
Neisseria meningitis
1 meningitis in school-age childeren and college students
epidemics in schools/day cares
Neisseria meningitis
Virulence factors:
Polysaccharide capsule (antiphagocytic)
Pili (attachment)
Porin proteins
Endotoxin
IgA protease
Disseminated Intravascular Coagulation
Neisseria meningitis
Gram negative cocci (pairs)
Gonorrhea
Pharyngitis
Rectal Infection
Neisseria gonorrhea
Beta lactamase
Pili
Porin proteins
Endotoxin
Neisseria gonorrhea
Requires enriched media
Beta lactamase test needed
Neisseria gonorrhea
Small, atypical gram negative
Obliagte intracellular parasite
Chlamydia trachomatis
infectious form; metabolically inactive; moderately resistant to harsh environment
(form of Chlamydia)
Elementary bodies
convert in RB
noninfectious; metabolically active
form of Chlamydia
Reticulate Bodies (RB)
Lipopolysaccharide
Major Outer Membrane Protein (MOMP) - important structural component of cell wall
Chlamydia trachomatis
Chlamydia reproduction?
EB enters host cell
EB converts to RB (inclusions)
RB replicates and produces EB
non-gonococcal urethritis
Chlamydia trachomatis
(a) Incubation 7-14 days
(b) Urethritis in male – may lead to epididymitis and infertility
(c) Cervicitis in female, usually asymptomatic – Often leads to salpingitis and infertility or acute pelvic inflammatory disease
(d) Often acquired concurrently with gonorrhea and persists after gonorrhea has been successfully treated
Chlamydia trachomatis
Inclusion conjunctivitis disease – a leading cause of blindness
Trachoma
Chlamydia trachomatis
involvement of inguinal lymph nodes.. what STI?
Lymphogranuloma venereum
Agent of pneumonias, bronchitis, sinusitis – usually asymptomatic or mild with persistent cough
Probable agent of atherosclerosis – inflammation of endothelium of blood vessels which then leads to plaque buildup
Chlamydia pneumoniae
Atypical bacterium – no cell wall, small, poorly staining
Etiological agent of “primary atypical pneumonia” (walking pneumonia)
Mycoplasma pneumoniae
Symptoms (after 1-3 weeks incubation): headache, malaise, cough (often paroxysmal), and less often chest discomfort
Sputum production may be scant; infiltration of lungs may be more extensive than clinical findings suggest
Pneumonia may progress from one lobe to another and may be bilateral (“walking pneumonia”)
Duration of illness: often more than a month
Epidemiology – occurs primarily in school age children and young adults, especially military (up to 50/1,000/year)
“primary atypical pneumonia” (walking pneumonia)
Mycoplasma pneumoniae
“Atypical” bacteria – small, coccobacilli, obligate intracellular parasites
Various species cause spotted fever or typhus
Rickettsia and Orientia species
Rocky Mountain Spotted Fever – Tick – Spotted Fever
Rickettsia Rickettsi
Epidemic typhus (classical typhus fever - louse)
Murine typhus (flea)
Scrub typhus (mite)
R. Rickettsii
R. typhus
O. tsutsugamushi
Transmitted by tick, mite, body louse, flea (species specific)
Clinical manifestations: abrupt onset (usually), fever (2-3 weeks), headache, severe deep muscle pain, and rash (no eschar from primary pathogens) (location not at site of entry)
Rickettsia and Orientia species
various types of Typhus
“Atypical” bacteria – small, coccobacilli, gram-negative but does not stain well
Obligate intracellular parasites with multi-stage developmental lifecycle
Biological threat agent
Etiologic Agent of Q Fever
Coxiella burnetti
Symptoms – high fever, headache, myalgias, arthralgias, cough, and involves multiple organs
Highly infectious/communicable via body fluids and aerosol to other animals and humans
Disease of numerous animals, especially sheep, goats, cattle
Q Fever
Coxiella burnetti
Acid-fast bacilli – large amounts of mycolic acids and lipids in cell wall impairs staining with aqueous stains
Mycobacterium tuberculosis and related mycobacteria
world’s leading infectious disease
TB
Mycobacterium tuberculosis
Highly communicable via aerosols or dust particles
Prevalent in AIDS patients, crowded populations (e.g. prisons), and street people
Mycobacterium tuberculosis
Bacteria are contained within tubercles
Mild and often asymptomatic (flu-like symptoms possible)
Spontaneous healing – calcified tubercles – occurs in about 75% to 90% of the cases
Primary tuberculosis
No true medical disease, just potential presence of live bacteria within tubercules
No clinical symptoms
No shedding of bacteria
Latent phase
The centers of the tubercles become necrotic and advance to form acellular masses of cheesy debris – caseous material. Ghon complex – combination of tubercles in the lung and caseation in lymph nodes
clinical disease
Secondary tuberculosis
Rapid failure of Cell Mediated Immunity may lead to disseminated miliary ___.
(lesions resembles grains of millet (bird seed))
TB
(1) Commonly recovered from AIDS patients
(2) May cause chronic pulmonary lesions and lymphadenitis
(3) Highly resistant to many of the traditional antituberculosis drugs
M. avium-intracellulare complex (MAI)(MAC)
MOTT
Mycobacteria other than ____ are collectively referred to as MOTT
M. tuberculosis
Gram-positive bacillus, aerobic, non-sporeforming (NSF)
Grows at refrigerator temperature
Source: soil, forage, animal feces
Listeria monocytogenes
Food poisoning (esp. cold cuts, unpasteurized cheeses); tolerates & grows in cold temperatures (e.g. refrigerated foods)
Intracellular pathogen
Miscarrage, stillbirth, neonatal infection
Encephalomeningitis
Listeria monocytogenes
Gram-positive bacillus, aerobic, non-sporeforming (NSF), pleomorphic
Etiologic agent of : Diphtheria
Corynebacterium diphtheriae
