Bacteria
Revision as of 09:20, 7 March 2016 by Jensflorian (talk | contribs) (→Actinomycetes: Actinomyces encephalitis - images added)
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
Bacteria are single celled microorganisms, without a nucleus (prokaryotes), that can cause lots of morbidity and mortality. They are not infrequently seen by pathologists.
Actinobacteria
General
- A very large group of bacteria.
It includes:[1]
- Actinomycetes.
- Corynebacterium.
- Mycobacterium.
- Nocardia.
- Streptomyces.
Actinomycetes
General
- IUD needs to be removed if found on a pap test[2] - see gynecologic cytopathology.
- Gram-positive branching rods.
- Common in the tonsils.
- Part of the large Actinobacteria group.[1]
Notes:
- Mycete = fungus; these organisms have a fungus-like appearance.
- Also called pseudomycosis.
Gross
- Yellow granules.[3]
Microscopic
- Branching rods.
- Typically form pink/purple granules ("sulfur granule") that is surrounded by inflammatory cells (lymphocytes or neutrophils).
DDx:
- Nocardia.
Notes:
- Sulfur granule may be seen grossly - yellow.[3]
Images
Stains
- Gram +ve.
- AFB -ve.
- Nocardia +ve.
- PAS +ve.
- May be confused with a fungus!
- Grocott +ve.
Helicobacter pylori
- Commonly abbreviated H. pylori or HP.
General
- Gram-negative rods.[5]
- Causes gastritis - specifically Helicobacter gastritis.
- Associated with peptic ulcer disease, MALT lymphoma and gastric carcinoma.
Microscopy
Clostridium difficile
- Commonly C. difficile.
- Classic cause of pseudomembranous colitis.
General
- Gram positive bacillus.
One virulent strain is:[6][7] BI/NAP1.
- Deletion of tcdC locus.
- Resistant to fluoroquinolones (gatifloxacin and moxifloxacin).
Chlamydia trachomatis
- May be referred to as Chlamydia.
General
- Common.
- May cause lymphogranuloma venereum.
Note:
- Often co-exists with gonorrhea.
Microscopic
- Variable.
Lymphogranuloma venereum:
- See: Cat-scratch disease.
Mycobacterium tuberculosis
- Abbreviated TB.
General
- Causes tuberculosis.
- May mimic a malignancy.
- Strong association with HIV.
- TB has characteristics of Gram positive and Gram negative bacteria.[8]
Clinical
Classic features - pulmonary/systemic:
- Cough.
- Fever.
- Weight loss.
CNS manifestations:
- Tuberculoma (mass).
- Meningitis.
- Abscess.
Tests:
Treatment:
- Multiple drugs for a long time (months).
- Commonly used drugs: isoniazid, rifampin, pyrazinamide, and ethambutol.
Gross
Ghon complex
Consists of two components:[12][13]
- Peripheral focus - subpleural, calcified.
- Central focus - the hilar lymph node that drains the peripheral focus.
Image:
Microscopic
Features:
- Necrotizing granulomas with rod-shaped bacteria.
Note:
- May be non-necrotizing.
DDx:
Images:
- Tuberculosis - case 1 - several images (upmc.edu).
- Tuberculosis - case 2 - several images (upmc.edu).
- Tuberculosis - case 3 - several images (upmc.edu).
Stains
- Ziehl-Neelsen stain - red rod-shaped bacteria - key feature.
- Very small - must use 40x objective.
Image:
Molecular
- Can be diagnosed with PCR.
Mycobacterium leprae
General
- Causes leprosy.
Clinical:
- Nerve damage -> injuries -> disability.
Microscopic
Features:
- Granulomas with rod-shaped bacteria.
Stains
- Fite stain - red rod-shaped bacteria - key feature.
- Very small - must use 40x objective.
Images:
Mycobacterium avium complex
- Abbreviated MAC.
- Previously referred to as Mycobacterium avium-intracellulare, abbreviated MAI.
General
- Refers to an infection with both:[16]
- Mycobacterium avium
- Mycobacterium intracellulare.
Microscopic
Features:
- Small rod-shaped organisms - within histocytes.
- +/-Granulomas.
DDx:
- Tuberculosis.
- Whipple disease - esp. in the duodenum.
Stains
- AFB +ve.
Coxiella burnetii
General
- Causes: Q fever.
Features:
- Intracellular bacterium.
- Gram negative.
Clinical:
- Flu-like symptoms.
Microscopic
Features:
- Fibrin ring granuloma.
- Epithelioid macrophages (i.e. a granuloma) surrounding a thin pink (fibrin) ring.
DDx:[17]
- Infections (Coxiella burnetii, CMV, EBV + others).
- Drug reaction.
- Malignancy (e.g. Hodgkin lymphoma[18]).
Images:
Bartonella henselae
General
Causative agent in:
Microscopic
Features - bacillary angiomatosis:
- Similar to pyogenic granuloma - see pyogenic granuloma.
Features - cat-scratch disease:
- Stellate granulomas.
Stains
- Warthin-Starry stain +ve.
Image:
Lactobacillus
General
- Gram positive bacilli.
- Normal vaginal flora.
Microscopic
Features:
- Slender bacilli.
Pseudomonas
General
- Gram-negative bacteria.
- Common pathogenic Pseudomonas aeruginosa.
- Community-acquired bronchopneumonia.
Gross
- Green nail.
Images:
Sarcina
Main article: Sarcina
See also
References
- ↑ 1.0 1.1 Ventura, M.; Canchaya, C.; Tauch, A.; Chandra, G.; Fitzgerald, GF.; Chater, KF.; van Sinderen, D. (Sep 2007). "Genomics of Actinobacteria: tracing the evolutionary history of an ancient phylum.". Microbiol Mol Biol Rev 71 (3): 495-548. doi:10.1128/MMBR.00005-07. PMC 2168647. PMID 17804669. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2168647/.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 446. ISBN 978-0781765275.
- ↑ 3.0 3.1 3.2 URL: http://pathmicro.med.sc.edu/mycology/mycology-2.htm. Accessed on: 14 September 2011.
- ↑ URL: http://pathology.class.kmu.edu.tw/ch05/Slide42.htm . Accessed on: 14 September 2011.
- ↑ Mobley, HLT.; Mendz, GL.; Hazell, SL.; Andersen, LP.; Wadström, T.. Basic Bacteriology and Culture. PMID 21290743. http://www.ncbi.nlm.nih.gov/books/NBK2444/.
- ↑ URL: http://www.medpagetoday.com/InfectiousDisease/PublicHealth/2254. Accessed on: 15 August 2011.
- ↑ McDonald, LC.; Killgore, GE.; Thompson, A.; Owens, RC.; Kazakova, SV.; Sambol, SP.; Johnson, S.; Gerding, DN. (Dec 2005). "An epidemic, toxin gene-variant strain of Clostridium difficile.". N Engl J Med 353 (23): 2433-41. doi:10.1056/NEJMoa051590. PMID 16322603.
- ↑ Fu, LM.; Fu-Liu, CS. (2002). "Is Mycobacterium tuberculosis a closer relative to Gram-positive or Gram-negative bacterial pathogens?". Tuberculosis (Edinb) 82 (2-3): 85-90. PMID 12356459.
- ↑ Kawakami, S.; Kawamura, Y.; Nishiyama, K.; Hatanaka, H.; Fujisaki, R.; Ono, Y.; Miyazawa, Y.; Nishiya, H. (Dec 2012). "Case of Mycobacterium tuberculosis meningitis: Gram staining as a useful initial diagnostic clue for tuberculous meningitis.". J Infect Chemother 18 (6): 931-6. doi:10.1007/s10156-012-0382-y. PMID 22476652.
- ↑ Atsukawa, Y.; Kawakami, S.; Asahara, M.; Ishigaki, S.; Tanaka, T.; Ono, Y.; Nishiya, H.; Fujisaki, R. et al. (Aug 2011). "The usefulness of changing focus during examination using Gram staining as initial diagnostic clue for infective tuberculosis.". J Infect Chemother 17 (4): 571-4. doi:10.1007/s10156-011-0216-3. PMID 21327691.
- ↑ Fu, LM.; Fu-Liu, CS. (2002). "Genome comparison of Mycobacterium tuberculosis and other bacteria.". OMICS 6 (2): 199-206. doi:10.1089/153623102760092797. PMID 12143965.
- ↑ Rose, Alan G. (2008). Atlas of Gross Pathology with Histologic Correlation (1st ed.). Cambridge University Press. pp. 112. ISBN 978-0521868792.
- ↑ URL: http://pathhsw5m54.ucsf.edu/case32/image324.html. Accessed on: 27 February 2012.
- ↑ URL: http://www.medscape.com/viewarticle/576467_2. Accessed on: 2 January 2012.
- ↑ URL: http://www.meddean.luc.edu/lumen/MedEd/orfpath/bfsrinf.htm. Accessed on: 1 April 2012.
- ↑ Turenne, CY.; Wallace, R.; Behr, MA. (Apr 2007). "Mycobacterium avium in the postgenomic era.". Clin Microbiol Rev 20 (2): 205-29. doi:10.1128/CMR.00036-06. PMC 1865596. PMID 17428883. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1865596/.
- ↑ Tjwa M, De Hertogh G, Neuville B, Roskams T, Nevens F, Van Steenbergen W (2001). "Hepatic fibrin-ring granulomas in granulomatous hepatitis: report of four cases and review of the literature". Acta Clin Belg 56 (6): 341–8. PMID 11881318.
- ↑ de Bayser L, Roblot P, Ramassamy A, Silvain C, Levillain P, Becq-Giraudon B (July 1993). "Hepatic fibrin-ring granulomas in giant cell arteritis". Gastroenterology 105 (1): 272–3. PMID 8514044.
- ↑ 19.0 19.1 Barankin, B.; Levy, J. (Oct 2012). "Dermacase. Can you identify this condition? Pseudomonas aeruginosa infection.". Can Fam Physician 58 (10): 1103-4. PMID 23064921.
- ↑ Hengge, UR.; Bardeli, V. (Mar 2009). "Images in clinical medicine. Green nails.". N Engl J Med 360 (11): 1125. doi:10.1056/NEJMicm0706497. PMID 19279344.