Microbiology: rickettsia, chlamydia and mycoplasma

how can C.trachomatis and C.psittaci can bbe differentiated on the biasis of?

-C.trachiomatis strains are sensitive to sulfonamide and produce iodine staining glycogen-like material in the inclusion body -C.psittaci strains are resistant to sulfonamide and its inclusions do not stain with iodine

what is Mycoplasmas? characteristics, shape, origin

-lack cell wall free-living (not intracellular) -coccoid, filamentous or cocci in chains -found in human, animals, soil, and plants -stable in ordinary culture media because of the presence of sterol in the cytoplasmic membrane -most species are aerobes or facultative anaerobes -few species require anaerobic conditions for initial isolation

is mycoplasm aerobic or anaerobic?

-most species are aerobes or facultative anaerobes -few species require anaerobic conditions for initial isolation

what are the general characteristics of rickettsia?

-pleomorphic coccobacilli, -they possess a three-layered cell wall associated with other gram-negative bacteria, -some have an extracellular slime layer, -the stain poorly in gram staining technique, but are better observed in preparations stained by Giemsa (tissue will be blue and the bac will be red(basic fusion))or macchiavello methods -can be cultivated in the yolk sac of embryonated eggs, in the lab animals, in ceratin arthropods, and in some tissue culture. -they divide by transverse division -suseptible to heat, drying, chemicals and antibiotics.

prevention of Chlymidia?

-vaccine for trachoma(trial) -prevention of Psittacosis is dependant on preventing avian infection -erythromycin or tetracycline drops prevent chlamydial conjuctivities

how to diagnose rickettsia?

1- stain tissue 2-serological tests, -indirect immunofluorescence -latex agglutination -elisa -weil felix reaction: the polysaccharide of 3 proteus strains (OX-19, OX-2 AND OX-K) agglutinate antibodies produced from rickettsia infection

what is the diagnosis of chlamydia trachomatis?

1-cell culture systems: intracytoplasmic inclusions can be identified in infected cell culture by staining with -Giemsa -macchiovello -Gimenez -iodine 2-fluorescent antibody tests 3-monoclonal antibodies 4-PCR

what is the lab diagnosis of M.pneumonia?

1-on blood agar they produce beta hemolysis. all other species (M.hominis) exhibit alfa or gamma hemolysis 2-they can reduce tetrazolium salts. the area under the colonies appears pink 3-colonies flooded with sheep erythrocytes and then stained. the erythrocytes coat the colonies of M.pneumonia but not those of other species

what do most mycoplasmas need for optimum growth?

30-36 °c in alkaline medium

what is the reproductive cycle of chlamydiae?

the environmental stable infectious particle is a small cell (elementary body EB) about 0.3 micrometer diameter, the EB have high affinity for host epithelial cells and rapidly enter them, EB are usually seen attached near the base of microvilli where they are subsequently engulfed by host cell, shortly after entery host the EB will be reorganized into bigger cell called RETICULATE BODY RB measuring 0.5-1 micometer within the membrane-bound vacuole RB grows in size and divides repeatedly by binary fission. finally the entire vacuole become filled with EB derived from RB to form a cytoplasmic inclusion. the newly formed EBs may be liberated from the host cell to infect new cells . the cycle takes 24-48 h

what is weil felix reaction?

the polysaccharide of 3 proteus strains (OX-19, OX-2 AND OX-K) agglutinate antibodies produced from rickettsia infection

how do colonies appear in agar?

transparent to the naked eye. wuth hand lens or microscope reveals a colony with a dense central area and a transparent periphery (look like fried egg)

how to control rickettsia?

use of repellents and personal hygiene, since it is a self limiting disease and occur frequently, vaccination programs have met with little success.

what is M.pneumoniae?

Mycoplasmas disease causes atypical pneumonia in human, may infect animals and cause lung inflammation and mastitis

why is mycoplasm stable in ordinary culture media?

because of the presence of sterol in the cytoplasmic membrane

why is chlamydiaceae known as energy parasite?

because they depend on host energy source

what is orientia tsutsugamushi?cause, transmissionand symptoms

cause scrub typhus, transmitted by mites, cause rash and enlargement of spleen

what is rickettsia prowazeckii? cause and transmission

cause typhus fever and transmitted by louse , was an epidemic disease

what is the shape of rickettsia?

coccobacili

what is the shape of chlamydiaceae?

coccoid

What is Chlamydia trachomatis?

disease causing - ocular diseases: trachoma and inclusion conjunctivitis which affects infants and adults. it could be complicated into neonatal pneumonia -male genital tract disease: urethritis. causative agent of >50% of non-gonoccal urethritis(NGU). -female genital tract disease infection of endocervix and pelvic inflammation disease result in infertility, premature birth, and still birth

treatment of M.pneumonia?

erythromycin and tetracycline are effective in the treatment of mycoplasma pneumonia erythromycin is preffered fore children because of the risk of staining immature teeth if tetracycline is used for a prolonged time formalin killed vaccine and live vaccine are currently being evaluated

what is chlamydophila psittaci? origin, cause and trabsnission

found in birds and other domestic and wild animals, causes psittacosis: an infection occurs in avian and mammalian but only avian strains can transmit to human, pets and wild birds transmit the sign of disease, infected birds show no clinical signs of disease

how to stain rickettsia?

giemsa stain or macchiavello method

how is the membrane of rickettsia?

have 3 layer cell wall associated with other gram negative bacteria and some possess extracellular slime layer

how is the outer layer of chlamydiaceae?

have no peptidoglycan layer but have an outer membrane composed of a single layer of protein

what is rickettsia susceptible of?

heat, drying, chemicals and the antibiotics

chlamydiae grow in where?

in cultures of a variety of eukaryotic cell line

where do chlamydiae proliferate?

in embryonated eggs, particularly in the yolk sac

where can rickettsia be cultivated

in the yolk sac of embryonated eggs, in lab animals, in certain arthropods and in some tissue cultures

what is chlalmydiaceae?

it is the family of bacteria belonging to phylum chlamydiae, order of chlamydiales, and include two genera: chlamydia and chlamydophila, gram-negative, non-motile, coccoid in shape, intracellular parasites with a life cycle

How is the C.psittaci in human?

it is usually asymptomatic. but atypical pneumonia may develop, after incubation of 1-3 weeks they can develop chills, fever, headache, persistent cough. Symptoms subside in less than 2 weeks

what are the general characteristicts of rickettsiaceae?

mainly diplococcus but can be rod-shaped or coccoid gram-negative obligatory intracellular (need host) intimately associated with arthropod hosts no flagella or endospore no member of the fam has yet been cultivated in cell-free media include the genera rickettsia and orienta

how is the laboratory cultivation in the mycoplasmas?

need basal medium of meat infusion and peptone supplemented with horse serum , thalium acetate and antibiotics.

what is the family of rickettsia?

rickettsiaceae

how do rickettsia divide?

tansverse division

What is the treatment for rickettsia?

tetracycline or chloramphenicol, drug of choice

treatment of chlymidia

tetracycline(choice) , erythromycine(alternative), sulfisoxazole(alternative to tetracycline for pregnant women) for incomplicated infection (tetracycline) but alternative amoxicillin or aqueous penicillin G