MMIC CASE 4 (2nd posting)

Particulars of patient
Name: Tong Wei Hong

Sex: Male

Age: 68 years

Clinical diagnosis
Complaints: Fever, chills, excessive phlegm, breathing problems

Diagnosis: Bronchitis

Possible Microorganisms	Description	Microscopy	Culture	Biochemical Tests
Streptococcus pneumoniae	- Gram-positive - Alpha-hemolytic diplococcus bacterium - Fermentative aerotolerant anaerobe - Members of the genus Streptococcus - Found in the nasopharynx - Major cause of pneumonia	Gram stain: Gram positive, lancet-shaped diplococcus (stained purple)	1) Blood agar plate (BAP) with added optochin antibiotic disk: alpha-hemolytic (green) colonies and a clear zone of inhibition around the disk	1) Catalase test: Catalase-negative
Haemophilus influenzae	-Non-motile gram-negative coccobacillus -Found in the upper respiratory system of humans -Major cause of lower respiratory tract infections, associated with pneumonia	Gram stain: Gram negative coccobacilli, with no specific arrangement (stained pink)	1) Chocolate agar (with factor X (heme) and factor V (NAD)): Flat, greyish-brown colonies colonies with diameters of 1-2mm	1) Catalase test: Catalase-positive 2) Oxidase test: Oxidase-positive
Moraxella catarrhalis	-Gram-negative, non-motile, aerobic, oxidase-positive diplococcus cocci -Produce beta-lactamase -Major cause of respiratory tract-associated infection, associated with bronchopneumonia	Gram stain: Gram negative kidney bean shaped diplococcus (stained pink)	1) Enriched media (e.g. Mueller-Hinton, modified Thayer-Martin): Non-pigmented or pinkish-grey opaque colonies 2) Chocolate blood agar: Opaque and non-hemolytic colonies being pushed along the surface of the agar like a hockey puck	1) Oxidase test: Oxidase-positive 2) Catalase test: Catalase-positive
Mycoplasma pneumoniae	-Small bacterium lacking a peptidoglycan cell wall -Member of the class Mollicutes -Uniform granular appearance	Nil	Nil	Nil
Chlamydia pneumoniae	-Small bacterium -Produces round, dense, glycogen-negative inclusion -Elementary bodies with pear-shaped appearance	Nil	Nil	Nil
Bordetella pertussis	-One of Bordetella species -Minute gram-negative, aerobic coccobacillus	Gram stain: Gram negative coccobacilli, with no specific arrangement (stained pink)	1) Enriched media- Bordet-Gengou medium (potato-blood-glycerol agar) or BCYE plate that contains penicillin G, using immunofluorescence staining: Mercury-drop colonies Small, faintly staining gram-negative rods	1) Urease test - Urease-negative 2) Nitrase test - Nitrase-negative 3) Citrate test - Citrate-negative 4) Oxidase test - Oxidase-positive

Possible Microorganisms	Serology	Others	Antibiotic Susceptibility Test	Treatment
Streptococcus pneumoniae	Nil	1) Bile solubility: Colonies soluble in bile 2) Capsule swelling test (Quellung reaction): Capsular swelling in the presence of antisera; Quellung reaction-positive	-Resistant to cephalosporins, macrolides (such as erythromycin), tetracycline, clindamycin and the quinolone -Susceptible to Vancomycin	Vancomycin in combination with β-lactam antibiotics
Haemophilus influenzae	Nil	Nil	Susceptible to ampicillin, cephalosporins, cefotaxime	Ampicillin (or amoxicillin) if β-lactamase-negative; cefotaxime (IV) or ceftriaxone
Moraxella catarrhalis	Nil	1) Deoxyribonuclease (DNase) test: Presence of DNase 2) Nitrate reduction test: Nitrate and nitrite levels are reduced.	Susceptible to trimethoprim-sulfamethoxazole, fluoroquinolones, cephalosporins, amoxicillin-clavulanic acid	Trimethoprim-sulfamethoxazole, amoxicillin-clavulanic acid, fluoroquinolones or cephalosporins
Mycoplasma pneumoniae	1) Complement-fixation test: Detects both IgG and IgM specific to M. pneumoniae. A four-fold rise in complement fixation titer during the acute and convalescent phases is indicative of a M. pneumoniae infection. 2) Hemagglutination test: Positive blood test for cold-hemagglutinins A titer of 1:64 or more indicates infection of M. pneumoniae 3) Enzyme immunoassay: Presence of M. pneumoniae specific IgM	Nil	Susceptible to Macrolide antibiotics, doxycyclin, second generation quinolones, tetracyclines, erthromycin	Macrolide antibiotics, doxycyclin, second generation quinolones, tetracyclines, erthromycin
Chlamydia pneumoniae	1) Direct Fluorescent Antibody Test: Detection of IgM or IgG antibodies – a fourfold rise in either the IgM or IgG titers Presence of proteins (antigens) from Chlamydia pneumoniae	Nil	Susceptible to macrolides, tetracycline, fluoroquinolones, erythromycin, clarithromycin	Macrolides, tetracycline, fluoroquinolones, erythromycin, clarithromycin
Bordetella pertussis	1) Direct Fluorescent Antibody (FA) Test: Presence of antibodies Presence of proteins (antigens) from Bordetella pertussis	Nil	Susceptible to erythromycin	Erythromycin

Pictures of Possible Microorganisms:

Streptococcus pneumoniae on blood agar showing alpha hemolysis (green zone surrounding colonies). Note: the zone of inhibition around a optochin disk.

Streptococcus pneumoniae gram stain of a film of sputum

Streptococcus pneumoniae - Quellung (capsular swelling) reaction

Gram stain of Haemophilus influenzae

Haemophilus influenzae on chocolate agar

Moraxella catarrhalis on chocolate agar

Moraxella catarrhalis on BAP

Gram stain of Moraxella catarrhalis

Electron micrograph of Mycoplasma pneumoniae

Chlamydial inclusions containing pear-shaped C. pneumoniae elementary bodies. EB, elementary body; FG, fatty globules; N, nucleus

Photomicrograph of Bordetella pertussis bacteria using gram staining technique

References
1. http://www.google.com/ > image search > "microorganism name"
2. http://en.wikipedia.org/wiki/Main_Page > "microorganism name"
3. http://www.textbookofbacteriology.net/ > S.pneumoniae
4. Geo.F.Brooks, Janet S.Butel, Stephen A. Morse. (2004). Jawetz, Melnick, & Adelberg's Medical Microbiology Twenty-third Edition. Singapore: The McGraw-Hill Companines, Inc

Dorothy Png
TG01
0503239F