Micro - Clinical Bacteriology (Gram - Misc) Flashcards
Pg. 139-142 Sections include: Gardnerella vaginalis Rickettsial diseases and vector-borne illness Chlamydiae Chlamydia trachomatis serotypes Mycoplasma pneumoniae
What is the functional limitation of Chlamydiae, and why?
They are obligate intracellular organisms that cause mucosal infections; Chalmydiae cannot make their own ATP; Think: “Chlamys = cloak (intracellular)”
What (broad) kind of infections does Chlamydiae cause?
Mucosal infections
What are the 2 forms of Chlamydiae? What is important to remember about the differing roles/characteristics of these two forms?
(1) Elementary body - Infectious, enters cell via endocytosis. Transforms into reticulate body (2) Reticulate body - Replicates in cell by fissure, recognizes into elementary bodies; Think: “Elementary = Enfectious, Enters cell, Endocytosis, Reticulate = Replicates once in cell”
What 4 diseases/conditions does Chlamydia trachomatis cause?
(1) Reactive arthritis (Reiter syndrome) (2) follicular Conjuctivitis (3) Nongonococcal urethritis (4) Pelvic inflammatory disease (PID)
Besides C. trachomatis, what are the other species of Chlamydiae? How are they transmitted? What disease/condition do they cause?
(1) C. pneumoniae (2) C. psittaci; Transmitted by aerosol; Atypical pneumonia
What are the treatment options for Chlamydiae infection? Which is favored, and why?
Azithromycin (favored because one-time treatment) or Doxycycline
What is a notable reservoir for Chlamydophila psittaci?
Avian
How is a lab diagnosis of Chlamydiae infection made?
Cytoplasmic inclusion seen on Giemsa or fluorescent antibody-stained smear
What is unusual about the Chlamydial cell wall?
Lacks muramic acid
What are the serotypes of Chlamydia trachomatis? List them based on similar presentations.
(1) Types A, B, and C (2) Types D-K (3) Types L1, L2, and L3
What disease/condition(s) do C. trachomatis serotypes A, B, and C cause, and where in the world?
Chronic infection, cause blindness due to follicular conjuctivitis in Africa; Think: “ABC = Africa, Blindness, (Conjuctivitis)/Chronic infection and D-K - everything else”
What disease/condition(s) do C. trachomatis serotypes D-K cause?
Urethritis/PID, ectopic pregnancy, neonatal pneumonia (staccato cough), or neonatal conjuctivitis
How can neonatal Chlamydial disease be acquired?
During passage through infected birth canal
What disease/condition(s) do C. trachomatis Types L1, L2, and L3 cause? What characterizes it? How is it treated?
Lymphogranuloma venereum; small , painless ulcers on genitals => swollen, painful inguinal lymph nodes that ulcerated (“buboes”); treat with doxycycline
What condition/disease does Mycoplasma pneumoniae classically cause? How does it present clinically and appear on X-ray?
Atypical “walking” pneumonia; Insidious onset, headache, nonproductive cough, diffuse interstitial infiltrate, X-ray looks worse than patient
With what immunological finding(s) and/or process(es) is Mycoplasma pneumoniae infection (Atypical “walking” pneumonia) associated? What can result from this/these immunological finding(s)?
High titer of cold agglutinins (IgM), which can agglutinate or lyse RBCs
On what type of agar is Mycoplasma pneumoniae grown?
Eaton’s agar
How is Mycoplasma pneumoniae infection treated? What antibiotic is ineffective, and why?
Macrolide, doxycycline, or Fluoraquinolone (Penicillin ineffective since Mycoplasma have no cell wall)
How do Mycoplasma pneumoniae appear on Gram stain, and why?
Not seen on Gram stain; No cell wall
What important content does Mycoplasma pneumonia contain is its membrane, and what role does this play?
Bacterial membrane contains sterols for stability
In what patient population is Mycoplasma pneumonia more common? In what populations/settings are frequent outbreaks seen?
Patients < 30 years of age; Frequent outbreaks in military recruits and prisons
What kind of organism is Gardnerella vaginalis, particularly in terms of morphology and gram stain?
A pleomorphic, gram-variable rod
What condition does Gardnerella vaginalis cause, and how does this condition present?
Causes Vaginosis, presenting as a gray vaginal discharge with a fishy smell but nonpainful (vs vaginitis)
With what is Gardnerella vaginalis associated? What is an important distinction to make with regards to this association?
Associated with sexual activity, but not an STD
What pathogen causes Bacterial vaginosis? What characterizes/defines this condition?
Gardnerella vaginalis; Bacterial vaginosis is characterized by overgrowth of certain anaerobic bacteria in vagina
What pathogen causes Bacterial vaginosis? What microscopic finding suggests Bacterial vaginosis?
Gardnerella vaginalis; Clue cells (vaginal epithelial cells covered with bacteria) are visible under the microscope
How is Bacterial vaginitis due to Gardnerella vaginalis treated?
Metronidazole or (to treat anaerobic bacteria) clindamycin
What is a way to remember the histological finding, primary presentation, location, and pathogen associated with Bacteria vaginosis?
i don’t have a CLUE why I smell FISH in the VAGINA GARDEN = Clue cells, gray discharge with fishy smell, caused by Gardnerella vaginalis
What is the treatment for all Rickettsial disease and vector-borne illness?
Doxycycline
What finding separates Rickettsial infections from other tick-borne illnesses?
Rash in Rickettsial infections; No rash in non-Rickettsial infections
What pathogen causes Rocky Mountain spotted fever? What is its vector?
Rickettsia rickettsii, vector is tick
Where does Rocky Mountain spotted fever primarily occur? Again, what pathogen causes it?
Despite its name, disease occurs primarily in the South Atlantic states, especially North Carolina; Rickettsia rickettsii
Describe the rash seen in Rocky Mountain spotted fever.
Rash typically starts at wrists and ankles and then spreads to trunk, palms, and soles
What kind of growth/metabolic requirements does Rickettsia rickettsii have?
Rickettsiae are obligate intracellular organisms that need CoA and NAD+ because they cannot synthesize ATP
What are the kinds of Typhus caused by Rickettsial species? Which vector and Rickettsial species is associated with each?
(1) Endemic (fleas) - R. typhi (2) Epidemic (human body louse) - R. prowazekii
What kind of Typhus does R. prowazekii cause? How does the rash seen in this condition appear?
Epidemic typhus; Rash starts centrally and spread out, sparing palms and soles
What is the classic triad associated with Rocky Mountain spotted fever?
Headache, fever, rash (vasculitis);
What is the difference between the rashes seen in Rickettsial Rocky Mountain spotted fever versus Typhus?
Rickettsia rickettsii = Rash typically starts at wrists and ankles and then spreads to trunk, palms, and soles; R. prowazekii = Rash starts centrally and spreads out, sparing palms and soles; Think: “Rickettsii on the wRists, Typhus on the Trunk.”
What are the infections in which you see a palm and sole rash?
Palm and sole rash in seen in (1) Coxsackievirus A infection (hand, foot, and mouth disease) (2) Rocky Mountain Spotted Fever (3) Secondary Syphilis; Think: “you drive in CARS using your PALMS & SOLES”
What are pathogens that are related to Rickettsial pathogens but do not cause rash? What condition/disease does each cause?
(1) Ehrlichia - Ehrlichiosis (2) Anaplasma - Anaplasmosis (3) Coxiella burnettii - Q fever
What pathogen causes Ehrlichiosis? In what vector is this pathogen found? What characterizes Ehrlichiosis?
Ehrlichia; Tick; Monocytes with morula (berry-like inclusions) in cytoplasm
What pathogen causes Anaplasmosis? In what vector is this pathogen found? What characterizes Anaplasmosis?
Anaplasma; Tick; Granulocytes with morula in cytoplasm
What pathogen causes Q fever? How does it present? What is the source and mode of transmission of this pathogen? What is unique about this pathogen in contrast to related species?
Coxiella burnetii; Tick feces and cattle placenta release spores that are inhaled as aerosols (No arthopod vector); presents as pneumonia. Think: “Q fever is Queer because it has no rash or vector & its causative organism can survive outside in its endospore form. Not in the Rickettsia genus, but closely related.”
How does Q fever present?
Presents as pneumonia; Think: “Q fever is Queer because it has no rash or vector & its causative organism can survive outside in its endospore form. Not in the Rickettsia genus, but closely related.”
What is unique about Q fever (among other Rickettsial like diseases)?
Q fever = Queer because it has no rash or vector and its causative organism can survive outside in its endospore form
Again, what pathogen causes Q fever? How does it relate to the Rickettsial genus?
Coxiella burnettii; Not in the Rickettsia genus, but closely related
