UNUSUAL BACTERIAL PATHOGENS-MYCOBACTERIUM, MYCOPLASMAS, RICKETTSIAS, CHLAMYDIAS, SPIROCHETES, AND VIBRIOS
Mycobacterium tuberculosis (causative organism)
One third of the world’s population is infected with Mycobacterium tuberculosis
Small, aerobic, non-motile bacillus
Waxy lipid (mycolic acid) in cell wall, acid fast stain
Mycolic acid protects them against lysis once phagocytized
Waxy prevents desiccation, airborne transmission
Skin test to screen people. Positive indicates past infection or vaccination.
Tuberculosis = Disease
Not very virulent (5% exposed get disease)
Latent TB = Do not feel sick, asymptomatic, not infectious, positive TB test. Bacteria can become active so must treat with antibiotics (6-9 months)
TB Disease = Bacteria is active and dividing, transmitting bacteria. Signs and symptoms bad cough (3 weeks or more), chest pain, coughing up blood/sputum, weakness or fatigue, weight loss, no appetite, chills, fever, night sweats.
Kills 50% of infected if not treated
Drug resistance an issue because antibiotic regimen is long
Vaccine not used in US (low number or cases), 66% of cases in the U.S. are foreign born persons
Leading killer of HIV/AIDS patients
Mycoplasma pneumoniae (causative organism)
Lack cell walls, variety of shapes
Have sterols in cell membrane
Smallest, free-living microbe
Adhesin attaches it to lining of respiratory tract
Attachment decreases cilia motion, decreases mucus removal
Eventually kills epithelial cells
Atypical or walking pneumonia = Disease
Most common form of pneumonia kids ages 5-15
Occurs throughout the year; not seasonal
2 million cases per year in the US
1-4-week incubation period
Signs and symptoms fever, malaise, headache, sore throat, persistent unproductive cough (may last several weeks)
Transmitted via respiratory droplets (nasal)
Difficult to diagnose via staining
Rickettsia rickettsia (causative organism)
Obligate, intracellular parasite
Non-motile
Aerobe
American dog tick and rocky mountain wood tick are vector and reservoir bacteria in salivary glands
Rocky mountain spotted fever = Disease
1 week incubation period
Signs and symptoms fever, headache, chills, muscle pain, nausea, vomiting
90% get a spotty, non-itchy rash on trunk, appendages, palms and soles
50% of rash patients get subcutaneous hemorrhages called petechiae
Severe cases organ systems fail; 5% die
Chlamydia trachomatis (causative organism)
Non-motile
Obligate, intracellular parasites
No cell wall
Chlamydia = Disease
Most common reportable STD in U.S. (over 1.7 million cases per year)
Transmitted by unprotected sex and to babies via the birth canal
Chlamydia is known as a “silent” disease because about three quarters of infected women and about half of infected men have no signs or symptoms. If symptoms do occur, they usually appear within one to three weeks after infection
Women signs and symptoms abnormal vaginal discharge or a burning sensation when urinating. PID, infertility
Men signs and symptoms discharge from their penis or a burning sensation when urinating, burning and itching around the opening of the penis, infertility
Chlamydial infection in the rectum, throats
Treponema pallidum (causative organism)
Spirochete
Can’t be cultured
Glycocalyx
Syphilis = Disease
Approximately 115,000 cases per year in U.S.
Transmitted by unprotected sex and to babies (via the placenta)
PRIMARY SYPHILIS-Chancre small, painless, ulcer-like lesion 10-90 days (average 21) after infected at the portal of entry, Chancres lasts 3-6 weeks then disappear.
SECONDARY SYPHILIS-Signs and symptoms sore throat, headache, mild fever, malaise, muscle pain, widespread rash including palms and soles; persists for months.
LATENT SYPHILIS-Clinically inactive, most do not advance beyond this.
TERTIARY OR LATE SYPHILIS-15% of people with untreated syphilis get this; 10-30 years after infection. Dementia, blindness, paralysis, heart failure, gummas (rubbery painfully swollen lesions) on bones, nervous tissue, skin.
CONGENTIAL SYPHILIS-Mother to fetus (mom in latent), premature delivery, low birth weight, still birth, cataracts, deafness, seizures, death.
Borrelia burgdorferi (causative organism)
Spirochete
Transmission via deer tick (vector) bite, tick must stay attached 36-48 hours to transmit
Lyme disease = Disease
30,000 cases per year in the U.S.
Signs and symptoms expanding bullseye rash (12 inches or more) at site of infection within 3-30 days post tick bite (average 7 days) for 70%-80% of patients. Rash lasts several weeks. Other signs and symptoms malaise, headache, stiff neck, fatigue, fever, chills.
Neurological and cardiac issues in 10% of patients
Can lead to arthritis
Vibrio cholera (causative organism)
Vibrio (slightly curved bacillus)
Gram negative
Produced an exotoxin (enterotoxin) causes severe fluid and electrolyte loss
Oxidase positive
Motile
Cholera = Disease
Recent outbreaks in Africa, SE Asia, Haiti
Seven pandemics since 1800
3-5 million cases per year worldwide 100,000 deaths
Transmitted fecal-oral ingest contaminated food/water, often poor sewage treatment
Incubation period few hours to 5 days (2-3 days average)
Signs and symptoms abrupt, watery mucus diarrhea (rice water stool), vomiting, rapid heart rate, low blood pressure, thirst, muscle cramps. one liter of fluid lost per hour.
5% get severe disease dehydration/shock/death
No vaccine in the U.S. but there are 2 vaccines used in other countries
Campylobacter jejuni (causative organism)
Gram negative
Produced an exotoxin (enterotoxin)
Vibrio (slightly curved bacillus)
Oxidase positive
Motile
Normal flora of gastrointestinal tract of birds
Campylobacteriosis = Disease
2.5 million per yr. in US
Undercooked meat and poultry, unpasteurized dairy products
Incubation period 2-5 days
Signs and symptoms diarrhea (may be bloody), cramping, abdominal pain, fever, nausea, vomiting
50% raw chicken in contaminated. One drop of raw chicken juice has enough bacteria to cause illness
Self-limiting, usually resolves in 7 days
Proper food prep, cook thoroughly, pasteurize dairy products