Clinical Microbiology Flashcards
Skin infections (a few examples) - Gram (+)
Staphylococcus Aureus Streptococcus Pyogenes Bacillus Anthracis and Bacillus Cereus Corynebacterium Diphtheriae Peptostreptococci and Enterococci Erysipelothrix Rhusiopathiae
Skin infections (a few examples) - Gram (-)
Escherichia Coli Neisseria Meningitidis Proteus sp. Pseudomonas Aeruginosa Francisella Tularensis Yersinia Pestis Treponema Carateum and Treponema Pertenue
Wounds infections (a few examples) - Gram (+)
Staphylococcus Aureus
Streptococcus Pyogenes
Enterococci and Peptostreptococci
Clostridium Tetani and Clostridium Perfringens
Wounds infections (a few examples) - Gram (-)
Escherichia Coli Proteus Klebsiella Pseudomonas Aeruginosa Pasteurella sp. Bacteroides sp..
Bacteria causing endogenous and mixed abdominal infections (a few examples):
Aerobic and Facultative bacteria
Escherichia Coli
Enterococci
α-haemolytic streptococci
Bacteria causing endogenous and mixed abdominal infections (a few examples):
Obligate Anaerobic Bacteria
Bacteroidaceae
Anaerobic Cocci
Bacteria causing Peritonitis (a few examples):
S. Pneumoniae (Children)
Group A Streptococci
Bacteroids
Infections causing Cholecystitis and Cholangitis (a few examples):
Pseudomonas aeruginosa
Clostridium perfringens
Actinomyces sp
Fungi: Candida Albicans
Diagnosis of Infectious Peritonitis:
Sampling form: Peritoneal fluid (lavage), Blood, Pus, Gall.
Detection: Gram staining, aerobic and anaerobic bacteria, cultivation, antibiogram
Diagnosis of Infectious Cholecystitis:
Sample from: Gall (invasive techniques E.g. duodenal sonda) High Contamination→Quantitative cultivation: Germ number 105/ml means infection.
Detection: Gram staining, aerobic and anaerobic bacteria, cultivation, antibiogram
Diagnosis of Infectious Cholangitis:
Sample from: Blood, Liver biopsy, Gall (with percutan-transhepatic choledochus (PTC) or from duodenum zonda)
Detection: Gram staining, aerobic and anaerobic bacteria, cultivation, antibiogram
Abdominal Infections:
Surgical Therapy for appendicitis needs and Prophylaxis :
Appendectomy - in surgical prophylaxis Metronidazole
Abdominal Infections:
Medical Therapy for Complications such as perforation or long lasting cystic obstruction and appendicitis needs
Combination: Lactamase- stabilising penicillins or 2. - 3. Generation cephalosporins or fluoroquinolon, together with Metronidazole or Aminoglycoside
Bacteria causing ophthalmic infections (a few examples) - Gram (+):
Staphylococcus Aureus
Streptococcus Pyogenes
Streptococcus Pneumoniae
Bacteria causing ophthalmic infections (a few examples) - Gram (-):
Chlamydia Trachomatis Neisseria Gonorrhoeae Haemophilus Influenzae and Haemophilus Aegyptius Pseudomonas Aeruginosa Moraxella Lacunata Enterobacteriaceae
Viruses causing ophthalmic infections (a few examples):
Coxsackie Virus Adenovirus Herpes Simplex Virus (HSV1) Cytomegalovirus Varicella Zoster Virus (HHV3)
Bacteria causing air-borne upper respiratory tract infections (a few examples) - Gram (+):
(Pharyngitis, tonsillitis, otitis, epiglotitis, sinusitis)
Streptococcus Pyogenes Streptococcus Pneumoniae Staphylococcus Aureus Streptococcus B, C, G Arcanobacterium Corynebacterium Haemolyticum Enterococci and Peptostreptococci
Bacteria causing air-borne Upper Respiratory Tract infections (a few examples) - Gram (-):
(Pharyngitis, tonsillitis, otitis, epiglottitis, sinusitis)
Haemophilus Influenzae Neisseria Meningitidis Klebsiella sp. Pseudomonas Aeruginosa Acinetobacter sp. Neisseria gonorrhoeae Moraxella catarrhalis Bacteroidaceae and Enterobacteriaceae (Treponema Vincentii Complex) Chlamydia Trachomatis D-K Chlamydia Pneumoniae Xanthomonas Maltophilia
Diagnosis of agents causing air-borne upper respiratory tract infections:
- Sputum specimens (and Blood) are cultured for bacteria, fungi and viruses.
- Enzyme-linked immunoassay methods can be used for detections of microbial antigens as well as antibodies.
- Detection of nucleotide fragments specific for the microbial antigen in question by DNA probe or polymerase chain reaction can offer a rapid diagnosis.
Diagnosis of agents causing air-borne upper respiratory tract infections:
Culture of nasal washings is usually sufficient in _____ with bronchiolitis.
Bacterial Diagnosis of agents causing air-borne upper respiratory tract infections:
Culture of nasal washings is usually sufficient in infants with bronchiolitis.
Diagnosis of agents causing air-borne upper respiratory tract infections:
_________ staining technique can be used for legionellosis.
Diagnosis of agents causing air-borne upper respiratory tract infections:
Fluorescent staining technique can be used for legionellosis.
Treatment of agents causing air-borne upper respiratory tract infections:
Symptomatic treatment is used for most viral infections. Bacterial pneumonias are treated with antibacterials.
Prevention of agents causing air-borne upper respiratory tract infections:
A Polysaccharide vaccine against 23 serotypes of Streptococcus pneumoniae is recommended for Individuals at high risk.
Viruses causing air-borne Respiratory Tract infections (a few examples):
(Pharyngitis, tonsillitis, otitis, epiglottitis, sinusitis and Pneumonia)
Rhinovirus Coronavirus Influenza and Parainfluenza Virus Adenovirus Respiratory Syncytial Virus Epstein-Barr Virus Cytomegalovirus Herpes Simplex Virus Coxsackie Virus Measles Virus Varicella Zoster Virus
A Common Fungi that colonize that Upper respiratory Tract and possibly causing Pharyngitis:
Candida Albicans
Normal flora of the oral cavity: Anaerobic Bacteria (a few examples)
Peptostreptococcus
Veillonella
Actinomyces
Fusobacterium
Normal flora of the oral cavity: Aerobic Bacteria (a few examples)
Streptococcus
Haemophilus
Neisseria
Normal flora of the oral cavity: Parasites (a few examples)
Entamoeba
Trichomonas
Infective agents causing Esophagitis (Could be Iatrogenic):
Candida Albicans
Cytomegalovirus
Herpes Simplex Virus
Normal flora of the Stomach: Bacteria (a few examples)
Lactobacillus Casei
Streptococcus spp.
Helicobacter Pylori
Normal flora of the Small Intestine: Bacteria (Most are) Anaerobes (a few examples)
Peptostreptococcus
Porphyromonas
Prevotella
Agents causing Infection of Small Intestine (Could be Iatrogenic):
Salmonella Typhi and Salmonella Enteritidis
Campylobacter Jejuni
Normal flora of the Colon: Bacteria (a few examples)
Bifidobacterium Eubacterium Bacteroides Fragilis Enterococcus Escherichia Coli
Agents causing Infection of Colon (Could be Iatrogenic):
Bacteroides Fragilis VRE Pseudomonas Aeruginosa Clostridium Difficile EHEC Shigella Dysenteriae Entamoeba Histolytica
Normal flora of the Colon: Fungi (a few examples)
Candida Spp.
Normal flora of the Colon: Parasites (a few examples)
Blastocystis Chilomastix Endolimax Entamoeba Iodamoeba Trichomonas
Which Bacteria is able to synthesize Vitamin K and Biotin in the Colon? (For Extra Knowledge, Just one Example)
Escherichia Coli
Bacterial Pathogens of the faecal-oral route causing Bloody Diarrhea (a few examples):
Shigella EHEC Yersinia Enterocolitica Salmonella Campylobacter jejuni Aeromonas spc. Vibrio parahaemolyticus
Bacterial Pathogens of the faecal-oral route causing Watery Diarrhea (a few examples):
Shigella Vibrio Cholera ETEC, EIEC, EPEC Clostridium perfringens Clostridium difficile
Bacterial Pathogens of the faecal-oral route causing Typhoid fever (a few examples):
Salmonella Typhi Salmonella Paratyphi A, B Yersinia Enterocolitica Yersinia Pseudotuberculosis Campylobacter Fetus
Viral Pathogens of the faecal-oral route causing Diarrhea (a few examples):
Rotavirus Caliciviridae Flavivirus Orthomyxovirus Crimean-Congo Virus HHV-7
Protozoal Pathogens of the faecal-oral route causing Diarrhea (a few examples):
Entamoeba Histolytica Balantidium Coli Giardia Lamblia Cryptosporidium Blastocystis hominis
Helminth Pathogens of the faecal-oral route causing Diarrhea (a few examples):
Strongyloides Stercoralis
Normal Flora of the Anterior Urethra and Vagina - (a few examples):
Lactobacillus Casei Streptococcus spp. Staphylococcus Epidermidis Staphylococcus Saprophyticus Candida Albicans Ureaplasma spp.
The Most Important Microbial pathogens of the urinary tract :
Escherichia Coli Staphylococcus Saprophyticus Candida Albicans Neisseria Gonorrhoeae Chlamydia Trachomatis Ureaplasma spp.
Causative agents of Arthropod-borne Bacterial infections - (a few examples):
Rickettsia Prowazekii Rickettsia Rickettsii Coxiella Burnetii Francisella Tularensis Borrelia Burgdorferi Yersinia Pestis
Causative agents of Arthropod-borne Viral infections - (a few examples):
Togavirus (Alphavirus)
Flaviviruses (Dengue, Yellow Fever, West Nile)
Reovirus (Coltivirus )
Bunyaviruses (California Encephalitis +Rift Valley Fever)
Bacterial pathogens of food-poisoning and toxico-infections - Contaminated Milk (a few examples):
Salmonella Spp.
Campylobacter Jejuni
Yersinia Enterocolitica
Mycobacteria Tuberculosis
Bacterial pathogens of food-poisoning and toxico-infections - Contaminated Meat (a few examples):
Clostridium Perfringens
EHEC and EPEC
Campylobacter Jejuni
Yersinia Enterocolitica
Bacterial pathogens of food-poisoning and toxico-infections - Contaminated Rice (a few examples):
Bacillus Cereus
Bacterial pathogens of food-poisoning and toxico-infections - Contaminated Water (a few examples):
ETEC, EPEC and EIEC
Vibrio Cholerae
Zoonotic infections of Bacterial Origin (a few examples):
Anthrax: Bacillus Anthracis Typhus: Rickettsia Prowazekii Lyme disease: Borrelia Burgdorferi, Afzelii and Ganiri Leprosy: Mycobacterium Leprae Bubonic plague: Yersinia Pestis Q-Fever: Coxiella Burnetii Rabbit Fever: Francisella Tularensis Brucellosis: B. Suis, B. Melitensis, B. Abortus, B. Canis
Zoonotic infections of Viral Origin (a few examples):
Bird Flu: Influenza A virus Rabies: Rhabdovirus Lassa Virus Hantavirus Cardiovirus
Zoonotic infections of Parasitic Origin (a few examples):
Chagas disease: Trypanosoma Cruzi
Toxoplasmosis: Toxoplasma gondii
Leishmaniasis: Leishmania
Sleeping Sickness: Trypanosoma Brucei Gambiense
Zoonotic infections of Prion Origin (a few examples):
Mad Cow Disease/Creutzfeldt-Jakob disease (vCJD)
Most important bacteria causing Meningitis - Gram(+) (a few examples):
Streptococcus Pneumoniae
Streptococcus Agalactiae
Staphylococcus Aureus
Listeria Monocytogenes
Most important bacteria causing Meningitis - Gram(-) (a few examples):
Neisseria Meningitidis Haemophilus Influenzae Escherichia Coli Pseudomonas Aeruginosa Proteus
Most important bacteria causing Meningitis - Gram Intermediate (a few examples):
Mycobacterium Tuberculosis
Leptospira Interrogans
Most important bacteria causing Encephalitis - Gram(+) (a few examples):
Listeria Monocytogenes
Most important bacteria causing Encephalitis - Gram(-) (a few examples):
Borrelia Burgdorferi
Most important bacteria causing Encephalitis - Gram Intermediate (a few examples):
Rickettsia Prowazekii
Chlamydia Psittaci
What is the classical diagnostic triad of symptoms for Meningitis?
1) Nuchal rigidity
2) Sudden High fever
3) Altered Mental status
What type of Meningitis is presented along with rapidly-spreading petechial rash?
“Meningococcal” Meningitis (i.e. meningitis caused by the bacteria Neisseria meningitidis)
Meningitis - Sample taking? What is Checked?
CSF is examined for WBCs, RBCs, protein content and glucose level.
How can we tell based on the CSF-WBC what type (Bacterial/Viral) of Meningitis ?
The type of white blood cell predominantly present predicts whether meningitis is due to bacterial or viral infection.
(Lymphocytes = Viral and Neutrophills =Bacteria)
How can we tell based on the CSF-Glucose what type (Bacterial/Viral) of Meningitis ?
Bacterial: CSF glucose to serum glucose ratio is < 0.4 .
Viral: CSF glucose to serum glucose ratio is 1~
Apart from CSF-Glucose and CSF-WBC, What other more specific diagnostic Lab test are possible for Meningitis?
Microbiological culture, Latex agglutination, PCR (Especially after antibiotics), Limulus lysate test for Gram Negative (Endotoxin Sensitive).
Meningitis - Principles of Treatment and Initial Response
Medical Emergency: Empiric antibiotics even before LP. Prednisone (corticosteroid) reduces rates of mortality, severe hearing loss and neurological sequelae.
Bacteria causing Pneumonia - Gram(+) (a few examples):
Streptococcus pneumoniae Staphylococcus aureus Peptostreptococcus sp. Streptococcus pyogenes Enterococcus sp. Actinomyces sp. Nocardia sp. Bacillus anthracis
Bacteria causing Pneumonia - Gram(-) (a few examples):
Haemophilus influenzae Bacteroidaceae Legionella sp. Klebsiella pneumoniae Enterobacteriaceae Pseudomonas aeruginosa Moraxella catarrhalis Francisella tularensis Yersinia pestis.
Bacteria causing Pneumonia - Gram Intermediate (a few examples):
Mycoplasma pneumoniae Chlamydia Pneumoniae Chlamydia Psittaci Coxiella burnetii Mycobacterium sp.
Bacteria causing Whooping cough: (a few examples):
Bordetella Pertussis
Bordatella Parapertussis
Bacteria causing Tuberculosis: (a few examples):
Mycobacterium Tuberculosis
Mycobacterium Bovis
Mycobacterium Africanum
Diagnostic Measures of Lower Respiratory Tract Bacterial Infections:
Sample from secretions of pus.
Microscopy, Culture, Serology, PCR.
Bacterial exotoxins and the Related diseases:
Superantigens of S. Aureus and S. Pyogenes
Toxic shock syndrome: Superantigens bridge the MHC class II protein on antigen presenting cells with the T cell receptor on the surface of T cells with a particular Vβ chain
Bacterial exotoxins and the Related diseases:
Heat labile toxin of E.coli
Gastroenteritis:
Bind and activate guanylate cyclase, which leads to ↑cGMP. This leads to the loss of electrolytes and water from intestinal cells.
Bacterial exotoxins and the Related diseases:
Anthrax toxins of Bacillus anthracis
Anthrax:
EF + PA: increase in target cell cAMP level, localized edema; LF + PA: death of target cells and experimental animals
Bacterial exotoxins and the Related diseases:
Bordetella adenylate cyclase and Pertussis
Lymphocytosis and Bronchial Cell Death:
Increase in target cell cAMP level
Bacterial exotoxins and the Related diseases:
Botulinum toxin of Clostridium botulinum
Flaccid paralysis:
Decrease in peripheral, presynaptic acetylcholine release
Bacterial exotoxins and the Related diseases:
Cholera toxin of Vibrio cholerae
Cholera - Secretory Diarrhea:
Activation of adenylate cyclase, increase in cAMP level
Bacterial exotoxins and the Related diseases:
Diphtheria toxin of Corynebacterium Diphtheriae
Diphtheria - Pharyngeal Pseudomembranes:
Inhibition of protein synthesis
Bacterial exotoxins and the Related diseases:
Pseudomonas exotoxin A of Pseudomonas aeruginosa
Similar to Diphtheria - Pharyngeal Pseudomembranes:
Inhibition of protein synthesis
Bacterial exotoxins and the Related diseases:
Shiga toxin of Shigella Dysenteriae
Shigellosis:
Inhibition of protein synthesis and Cell Death
Bacterial exotoxins and the Related diseases:
Tetanus toxin of Clostridium tetani
Tetanus, Opisthotonus:
Decrease in neurotransmitter release from inhibitory neurons, spastic paralysis
Septic shock - Microbiologic Diagnosis
Diagnosis is made by culturing local infections thought to be the source of microbemia and by culturing the blood.
Septic shock - Prevention and Treatment
Treatment consists of high-dose intravenous broad-spectrum antimicrobial agents, intravenous fluids, supplemental oxygen therapy, mechanical ventilation, hemodialysis, and transfusions of blood products and clotting factors, as needed.
Endocarditis - Microbiologic Diagnosis
Infective endocarditis is diagnosed through blood cultures
Endocarditis - Prevention
Antimicrobial prophylaxis is administered to patients with defective heart valves who are undergoing dental and other procedures known to produce bacteremia.
Endocarditis - Treatment
Prolonged intravenous treatment with bactericidal antibiotics to eradicate bacteria within the protective clot. Surgical replacement of infected valves may be required to cure prosthetic valve infections.
Blood cultures - Initial Importance in Diagnosis
Most clinical laboratories will give a preliminary report of a negative culture if no growth is detected after 4 days of incubation. A final negative report is made if there is no growth after 7 days of incubation.
Blood cultures - What should be done if the patient has received antimicrobial agents before sampling?
The Clinical Laboratory can add penicillinase to remove β-lactam antibiotics, use an antimicrobial removal device or special resin bottle to remove or inactivate the antimicrobial agent, or prolong blood incubation for 2 weeks to improve the chances of obtaining a positive culture.
Blood cultures - What should be done If infective endocarditis is suspected?
Blood culture bottles should be incubated for 2 weeks to allow growth of slow-growing or fastidious microorganisms.
Blood cultures - What should be done If fungemia is suspected?
Special media and techniques are used to grow fungi
Blood cultures - What should be done If central venous catheter infection is suspected?
Blood should be drawn both from the line and from a peripheral vein, and the results of quantitative cultures compared. If the catheter blood culture has a 10-fold greater count than the peripheral blood culture or has more than 100 CFU/ml, the catheter is probably infected.
Serum Procalcitonin is a definite indication of a _______ Infection.
Serum Procalcitonin is a definite indication of a Bacterial Infection.
Serum Leukocytosis and CRP elevation is an initial indication of an _______ .
Serum Leukocytosis and CRP elevation is an initial indication of an Infection
In case of Transient Bacteremia blood sample should be taken from the patient at :
The beginning of the fever
In case of Continuous Bacteremia blood sample should be taken from the patient at :
Blood can be taken at any time
How blood should be taken for Blood culture from an Adult?
10-20 ml
How blood should be taken for Blood culture from an child?
1-2 ml
How many times do we need to sample blood for blood cultures? and from which vessels?
3 Times and from the Peripheral Veins
What pathogens require a special Blood culture mixtures?
Fungi and Mycobacteria
Liquid media for Anaerobic culture - Methods of Environment Production for Anaerobes
Before inoculation, O2 is eliminated from media by means of boiling. After inoculation, media are sealed by means of sterile wax or Vaseline.
Gas-pack jar (Compartment) - Methods of Environment Production for Anaerobes
Cultivation of Anaerobic microbes by - Placing a Gas Pack in the Jar that releases H2 and CO2, a Catalyst in the cell produces Water from O2 and H2 thus ultimately eliminating the Oxygen in the sealed Jar.
Anaerostate (Compartment) - Methods of Environment Production for Anaerobes
Cultivation of Anaerobic microbes by - Air Expulsion by Pressure Cylinder, Air Aspiration and Filling or Anaerocult that produces the Correct Gas mixture.
Biological method - Fortner-technique: Environment Production for Anaerobes
Growing Anaerobes and Aerobes together on Blood agar - Anaerobe over consume the Oxygen allowing for an Anaerobic environment for the other Anaerobe.
Chemical method - Liquid media for Anaerobic culture
Thioglycolate broth allows for reduction of Oxygen to water in the tube. Aerobes will culture the top of the liquid (Contact with air) anaerobe the bottom.
Types of metabolism preformed by aerobic and anaerobic bacteria?
Aerobic bacteria - Respiration
Anaerobic bacteria - Fermentation
Enterally acquired Parasitic infections - Indirect (fecal-oral) - give a few examples:
Entamoeba Histolytica Giardia lamblia Enterobius vermicularis Balantidium coli Ascaris lumbricoides Toxocara spp. Trichuris trichiura
Enterally acquired Parasitic infections - direct (venereal) - give a few examples:
Entamoeba Histolytica
Enterally acquired Parasitic infections - Contaminated Meat - give a few examples:
Taenia saginata
Taenia solium
Diphyllobothrium latum (Fish)
Enterally acquired Parasitic infections - Contaminated Eggs - give a few examples:
Echinococcus granulosus and multilocularis
Hymenolepis nana
What are the Microscopical Diagnostic Measures for Enterally acquired Parasitic infections?
Wet mount
Permanent stains
Stool concentrates
What are the Serologic Diagnostic Measures for Enterally acquired Parasitic infections?
ELISA: Antibody response or Antigen detection
What are the Nucleic acid hybridization Diagnostic Measures for Enterally acquired Parasitic infections?
Restriction Endonuclease and PCR
What are the Unique options for Diagnosis of Enterally acquired Parasitic infections?
Animal inoculation and Culture
Causative agents associated with arthropod-borne Parasitic infections - Protozoa (few examples):
Plasmodium spp: Anopheles mosquito Toxoplasma gondii: Fecal-oral route, carnivorism Leishmania species: Phlebotomus sandfly Trypanosoma cruzi: Reduviid bug Trypanosoma brucei: Tsetse fly
Causative agents associated with arthropod-borne Parasitic infections - Helminths (few examples):
Wuchereria bancrofti: Mosquito
Loa loa: Chrysops fly
Onchocerca volvulus: Simulium black fly
Dirofilaria immitis: Mosquito
Plasmodium spp - Diagnostic Procedure
Blood Sample Microscopic examination (Giemsa stain) or acridine orange fluorescent stain:
●Thin film
●Thick film
Leishmania Donovani- Diagnostic Procedure
Bone Marrow Aspirate Microscopic examination (Giemsa stain), Culture, Serology (antibody).