Chapter 19B Flashcards
Name 7 G+ regular non spore forming rods
- Lactobacillus
- Listeria
- Erysipelothrix
- Kurthia
- Caryophanum
- Bronchotrix
- Renibacterium
The 7 are considered “regular” because
Regular because of uniform staining pattern and do not assume pleomorphic shapes
An emerging food borne pathogen
Listeria monocytogenes
L. monocytogenes is non _____
fastidious
L. monocytogenes is resistant to
cold, heat, salt, pH, and bile
L. monocytogenes is a contaminant of
unpasterurized dairy products and meats
______ is beta hemolytic
L. monocytogenes
L. monocytogenes is sensitive to
penicillin, ampicillin, and erythromycin
Name 4 gram +, irregular non spore forming rods
- Corynebacterium
- Mycobacterium
- Nocardia
- Propionibacterium
They are considered irregular because
- pleomorphic in shape
* stain unevenly
How many genera of Bacilli are G+, irregular, non spore forming
20 genera
Produce catalase, have mycolic acids, and have unique peptidoglycan
G+, irregular, non spore forming, rods
Corynebacterium diptheriae shape
curved rod that tapers at end
Corynebacterium diptheriae has thin spots in the cell walll that develop into ____, ____, and ____ shapes
club, filamentous, and swollen
C. diptheriae toxigenic strains produce exotoxin called
diphterotoxin
C. diphteriae has a high
morbidity and mortality rate in past but now there is an effective vaccine
How many cases of C. diphteriae in US
.01 cases per million
C. diphteriae is transmitted via
fomites, droplets, and contaminated milk
Portal of entry for C. diphteriae
upper respiratory tract
Aerotolerant, anaerobic, non toxigenic
Propionibacterium
Involved in infections of eye and joints
Propionibacterium
Propionibacterium is a resident of
pilosebaceous glands (P. acnes)
Propionibacterium is related to
acne vulgaris
Complex syndrome influenced by genetic hormonal factors as well as by epidermal structure
acne vulgaris
Acid - fast G+ bacilli
Mycobacterium
Describe Mycobacterium size
*about 50 spp
large amount of mycolic acid and waxes
Mycobacterium
strict aerobes
Mycobacterium
Slender filamentous rods
Mycobacterium
widely distributed, resistant to environmental conditions, and grow slowly
Mycobacterium
3 diseases caused by Mycobacterium
Tuberculosis
Leprosy
MOTT (Mycobacteria other than tuberculosis bacilli) - immunocompromised patients
M. tuberculosis are long thin rods that grow in
masses or cords
Cord factor of M. tuberculosis is involved in
virulence
Has No endotoxins or enzymes for infectiousness
M. tuberculosis
M. tuberculosis have ____ in cell wall
complex waxes
Susceptibility to M. tuberculosis due to: (6)
poverty bad nutrition poor hygiene low immune system lung damage genetics
Tubercules
TB bacillus inside macrophages with wall made of fibroblasts, lymphocytes, and neutrophils
Tuberculin
a skin test (cell mediated immune response)
Mantoux Test
M. tuberculosis mode of transmission (2):
fine droplets - cough, sneeze, expectoration
mucus and aerosols
M. tuberculosis minimum infectious dose
around 10 bacterial cells
How many people carry TB bacillus
1/3 of world population and 15 million Americans
Tuberculosis Bacillus is very resistant
survives up to 8 months in aerosols
TB: Humans are easily infected but
resistant to disease
Only ____ % of infected people actually develop clinical case of TB
5%
Untreated cases can last ______ with morbid episodes
a lifetime
85% of TB is in ____ but can be in other organs such as (lymph nodes, long bones, genital tract, brain, and meninges)
lungs
How many people die each year of TB
3 million
Texas has ___ national rate and RGV has ____ state rate for TB
2x and 2x
Biggest problem with TB in valley
drug resistance
4 Current drugs for TB
isoniazid, rifampin, pyrazinamine, and ethambutol
To avoid resistance therapy includes
2-3 drugs in combination
Some patients take up to
7-8 medications
How long do drugs take to kill bacilli ?
6 - 24 months
Vaccine is made of attenuated strain of M. bovis called
bacillus Calmet-Guerin (BCG)
______ % of vaccines give protection for several years
20 - 80%
Detection of TB
Acid-fast stain done for Mycobacterium spp
Test for TB is done in
sputum
________ shows bright red cells against blue back ground
Ziehl-Neelsen
_____ shows luminescence with a yellow green background
Fluorescence
What kind of media can TB be plated on? Name 2 of that kind
Egg-potato media
- Middlebrook 7H11
- Lowenstein Jensen media
How long will TB take to grow on egg-potato media?
8 weeks +
Latest technique for tb detection
PCR (gene amplification) - results in 24 hrs
M. leprae
causative agent of leprosy
strict parasite
M. leprae
Never grown on artificial media or human tissue culture
M. leprae
slowest growing bacterial species
M. leprae
Leprosy
chronic progressive disease of skin and nerves produced by M. leprae
Bacilli of leprosy are not
virulent
Bacilli of leprosy can be harbored through
lifetime
Incubation period for leprosy
2 -5 years or months to 40 years
What is unique about M. leprae
grown inside macrophages
2 natural resevoirs of leprosy bacillus
human body and armadillos
Leprosy: Predisposing factor for a defect in the regulation of
t cells
Leprosy causes
severe disfigurement - believed before as divine curse - lepers
Mechanism of transmission for leprosy
unknown! contact with leprotic? mechanical vectors? droplets? zoonosis (through armadillos)??
How many people have leprosy in the world?
In US?
15 million
2 - 3,000
How does one contract leprosy?
now believed that it is an immunological disorder that can be induced by the bacteria in immunocompromised people (5% of world population)
5 forms of leprosy
Tuberculoid leprosy (TT) Lepromatous leprosy (LL) Borderline tuberculoid (BT) Borderline (BB) Borderline lepromatous (BL)
Therapy for leprosy
a combined approach of Dapsone (DDS) and Rifampin
Vaccine for leprosy
currently under development by WHO
Mycobacterium avium complex (MAC)
Found in soil bacteria.
attacks AIDS patients
Has high drug resistance
3rd most common cause of death in AIDS patients
Mycobacterium avium complex (MAC)
Pulmonary infections by commensal mycobacteria (2)
M. kansasii (USA, UK)
M. fortuitum
Diseases by non commensal Mycobacteria (2)
M. marinum
M. scrofulaceum
M. marinum
Swimming pool granuloma
- affects elbows, knees, toes, fingers
M. scrofulaceum
Cervical lymph nodes
- found in Great Lakes region, Canada, and Japan
Tuberculin test
Protein of bacteria scratch skin
negative (0-5mm)
intermediate (5-9mm)
positive (>10 mm)
Prevention of tb
stay away from coughing people