This document discusses gram negative cocci, specifically Neisseria gonorrhea and Neisseria meningitidis. It provides details on the morphology, identification, culture characteristics and growth patterns of various Neisseria species. Key points include that Neisseria are gram negative diplococci that are oxidase and catalase positive. Identification involves examining colony morphology on specialized media like modified Thayer Martin and examining carbohydrate oxidation patterns in tests like cysteine trypticase agar.

1. Gram Negative Cocci
Neisseria gonorrhea
Neisseria meningitidis
• Common pathogen in man
• 70% they are related with DNA homology

2. Genera and Species
Neisseria
- N. gonorrheae= Gonococci
Encapsulated and have plasmids
- N. meningitidis= Meningococci
Capsulated and don’t have plasmids
Other Neisseria spp. (rare cause of infection)
-N. cinerea N. sicca N. flavescens
-N. lactamica N. subflava N. elongate(bacillus, - catalase)
-N. polysarccharea N.mucosa

3. Genera and Species
Moraxella catarrhalis
- Formerly Branhamella Neisseria catarrhalis
Veillonella
- GIT, GUT and RT
Family Neisseriaceae Genera:
• Neisseria- prevalent pathogen
• Kingella
• Cikenella
• Simonsiella
• Alysiella

4. Morphology and Identification
A. Typical Neisseria
 Gram negative diplococci
 Non-motile and non-spore forming
Approximately 0.8 um in diameter
Individual cocci is KIDNEY/COFFEE BEAN SHAPED (except
elongate)
 In pairs, the flat or concave sides are adjacent
Cytochrome oxidase and catalase POSITIVE
 Non pathogenic is the normal flora of the URT
Obligate aerobe at the same time they need O₂ (that’s why
catalase +)

5. Morphology and Identification
B. Culture (BAP/CAP)
 On enriched medium in 48 to 72 hours= capnophilic
 Gonococci/Meningococci
- convex, glistening, elevated, mucoid colonies 1-5 mm in
diameter
- Transparent or opaque, non-pigmented, non-hemolytic
- Pathogenic Neisseria
- Very fastidious which requires BAP and CAP (iron, hemin,
coenzyme 1)
- Gonococci need cysteine for growth

6. Morphology and Identification
B.Culture
 N. flavescens, N. cinerea, N. subflava, N.
lactamica may have YELLOW pigmentation
N. sicca produces opaque, brittle, wrinkled
colonies
Moraxella catarrhalis produces nonpigmented or
PINKISH GRAY opaque colonies

7. Morphology and Identification
C. Growth/Biochemical Characteristics
Neisseria grow best under aerobic conditions
Some grow best in anaerobic environment
Most oxidize carbohydrates with acid but no gas
Produce oxidase and give (+) oxidase reaction
Atmospheric requirement: 5% CO₂ in CANDLE JAR

8. Morphology and Identification
C. Growth/Biochemical Characteristics
• Modified Thayer Martin, Lewis Martin, GC-Lect, New York City
• MTM: vancomycin, colistin, nystatin, trimethoprim
• ML: anisomycin and trimethoprim
• Contain antimicrobial drugs
 vancomycin: inhibits gram positive bacteria (3 ug/mL)
 lincomycin: alternative for vancomycin
 colistin: inhibits gram negative bacteria
 amphotericin B
 nystatin: inhibits fungi
 anisomycin: used in LM instead of nystatin
 trimethoprim: inhibits swarming of proteus

9. Growth on MTM, ML, NYC
• Positive growth
- N. gonorrheae
- N. meningitidis
- N. lactamica
• Variable growth
- N. cinerea
- N. polysaccahareae
• Negative growth
- N. sicca -N. flavescens
- N. subflava -N. elongate
- N. mucosa -Moraxella catarrhalis

10. Morphology and Identification
C. Growth/Biochemical Characteristics
 Catalase positive
 Oxidase test: a key test for ID
DARK PURPLE
Rapid test- filter paper soaked with tetra-methyl-
paraphenylene diamine hydrochloride
 Most oxidize carbohydrates producing acid but not gas
 CARBOHYDRATE PATTERNS means of distinguishing
them
Cysteine Trypticase Agar (CTA) add sugars:
Glucose, Maltose, Lactose, Sucrose

11. Results CTA Carbohydrates
SPECIES OXIDASE GLUCOSE MALTOSE LACTOSE SUCROSE
N.
Gonorrheae
+ + - - -
N.
Meningitidis
+ + + - -
N.
Lactamica
+ + + + -
N.
Catarrhalis
(DNAse
positive)
+ - - - -

12. Morphology and Identification
C. Growth/Biochemical Characteristics
 Inhibited by toxic constituents (Fatty acids &
Salts)
Rapidly killed by drying, sunlight, moist heat, and
many disinfectants
Produce autolytic enzymes results in:
Rapid swelling
Lysis in vitro at 25⁰C and at an alkaline or high
pH