Neisseria spp. and Moraxella

Gram-negative diplococci (kidney bean shaped)

Almost always

-Neisseria gonorrhoeae

-Neisseria meningitidis

(PLUS Moraxella)

Mnemonic: “Nice Morons”

Neisseria identification

• Gram-negative cocci

  • Diplo, kidney-bean shape

  • Often clustered and intracellular

  • Two beans flat sides together

• Colonies are usually oxidase positive

Neisseria rapid tests

• Direct fluorescent antibody

• DNA probes

• MALDI-TOF

• DNA sequencing

• Antigenic tests

Moraxella catarrhalis lab testing

• Specimen

  • Exudate from infected area

  • Or swab

• Methods

  • Culture (identification in culture is similar to Neisseria)

Neisseria gonorrhoeae

• Only ferments glucose (lab test)

• Always a pathogen

• Isolated from urethra, cervix, rectum, pharynx

• Sometimes isolated from CSF, joints, skin

• Transmitted primarily by sexual contact

• Causes localized infection

• “Gonococcus” or “GC”

• Rarely lethal

• Killed rapidly in blood

• Very fastidious

• Not encapsulated

• Humans are the only known reservoir

Neisseria meningitidis

• Ferments glucose and maltose (lab test)

• Can be commensal

• Isolated from nasopharynx, blood, CSF

• Colonizes nasopharynx

• Transmitted by direct contact with respiratory secretions

• Causes systematic infection

• “Meningococcus”

• Life threatening

• Multiples rapidly in blood

• Not as fastidious-grows on sheep blood agar

• Capsules present

• Nasopharynx of human is the most common reservoir

Similarities of Neisseria gonorrhoeae and meningitidis

• Gram-negative diplococci

• Have pili for attachment to the host cells

• Aerobic 

• Prefer or require increased CO2 for growth

• Optimal growth at 35-7 degrees C in moist environment

• Fastidious (sensitive to drying and temperature)

• Non-motile

• Affinity for mucous membranes

Moraxella catarrhalis

• Gram-negative diplococci

• Not fastidious

• Normal microbiome upper respiratory tract

• Otitis media in children

• Sinusitis-all ages

• Pneumonia and bronchitis in immunocompromised persons

• Is the 2nd most common bacterial cause of COPD exacerbations after non-typeable Haemophilus influenzae

N. gonorrhoeae transmission and disease states

• Gonorrhea is an acute pyogenic infection of the mucosa-vaginal/urethrall, anal, pharyngeal

• N. gonorrhoeae can cause pharyngitis, suppurative arthritis, and ophthalmitis in newborns

• Can cause or be a co-infecting agent in pelvic inflammatory disease

• Has pili that helps bacteria to attach and infect male urethra

N. meningitidis transmission and disease states

• Nasopharynx of humans is the only reservoir

• Spread by respiratory droplets

• 5-15% of teenagers and young adults are carriers

• Outbreaks in closed populations such as frat houses, military barracks, dorms

• Menintisis-”medical emergency”

• Fever, headache, neck stiffness, photophobia, irritability

Gram-positive cocci

Think: Staph + Strep + Enterococcus

-Staphylococcus

-Streptococcus

-Enterococcus

Gram-negatice cocci

-Neisseria gonorrhoeae

-Neisseria meningitidis

Gram-positive bacilli

-Bacillus

-Clostridium

-Listeria

-Corynebacterium

Mnemonic: “Big Cats Love Cheese”