Gram Negative Cocci & Spirochetes

Neisseria species characteristics

GNC

Non-motile, non-spore forming

Oxidase +

Most are Catalase + and can't reduce nitrates

Neisseria identification

GNC in pairs, aka diplococci

"coffee bean" shaped

Neisseria growth factors

Prefer aerobic environments with increased CO2 & humidity

Incubate @35-37 Celsius

Require CHOC or GC plates

Detection of Neisseria

1. Nucleic Acid Probes

2. Agglutination tests

N. gonorrhoeae habitat

Unknown; never normal flora in humans

N. gonorrhoeae significance

STI through sexual contact with infected mucosal surfaces

DGI

Pharyngitis

Ophthalmia neonatorum

N. gonorrhoeae Lab ID

GS: GNDC

Requires special media, CHOC

Small, convex, grayish colonies

Oxidase & Catalase +

*Superoxl +

Utilizes glucose

Moraxella catarrhalis habitat

Normal flora of URT and GU tracts

Moraxella catarrhalis significance

is a contaminant in the lab, sometimes causes OI's

Moraxella catarrhalis Lab ID

morphology is similar to Neisseria - GNDC

Oxidase +

Catalase +

Assacharolytic & reduces nitrates

Spirochetes characteristics

small, Gram-negative coil-shaped organisms, motile, difficult to culture, must use special stains, diagnosis made by serological tests

Treponema general characteristics

Coil-shaped bacteria does not stain well or at all

Treponema Infections

T. pallidum subsp. pallidum - Venereal syphilis

T. pallidum subsp. pertenue - Yaws

T. pallidum subsp. endemicum - endemic venereal syphilis

T. pallidum subsp. carateum - Pinta

Primary Syphilis

Appearance of a large, painless chancre at the site of exposure, highly infectious

Secondary Syphilis

6-6months after the appearance of a chancre, widespread rash, and condyloma latum present

Tertiary Syphilis

5-30yrs after primary syphilis, damage to CNS and heart, gummata

Latent Syphilis

no symptoms but the infection is still present

Congenital Syphilis

Syphilis Diagnosis/Testing

serological testing, clinical symptoms, dark-field microscopy

Non-treponemal tests = RPR & VDRL

Treponemal test = TPI (standard), FTA-Ab, MHA-TP

Borrelia infectons

Lyme Disease - B. burgdorferi

Relapsing Fever - B. recurrentis & B. hermsii

Borrelia significance

Transmitted through a bite from an Ixodes tick; tick must be attached for 36-48 hours

Borrelia Lab ID

culture may be possible on Kelly's medium, patient history and serological testing are preferred, EIA, immunoassays, Western Blot

Lyme Disease: Stage 1

lesion & rash at the site of the bite, lymphadenopathy possible

Lyme Disease: Stage 2

Enters the blood and infects CNS, joints, heart, and liver

Lyme Disease: Stage 3

Chronic stage

Neurological issues, skin lesions, and arthritis

Relapsing Fever

caused by B.recurrentis & B.hermsii; recurrent high fever, delirium, and muscle aches

Relapsing Fever Lab ID

Thick & thin blood smears to examine spirochetes, Kelly's medium, serological testing, PCR

N. meningitidis habitat

colonizes the oropharyngeal & nasopharyngeal mucus membranes; often carried asymptomatically

N. meningitidis significance

Meningitis & Bacteremia, sinusitis, pneumonia, etc.

N. meningitidis virulence

Pili, polysaccharide capsule, endotoxins, IgA protease

N. meningitidis Lab ID

GS: intra & extracellular GNDC

Medium, round, grayish mucoid colonies on BAP, CHOC, and GC media

Oxidase & Catalase +

*Superoxl -

Utilizes glucose & maltose

Other Neisseria species habitat

Normal flora of URT & GU tract

Other Neisseria species' significance

OIs: Endocarditis, Meningitis, Bacteremia

Other Neisseria species Lab ID

Not fastidious organisms, most grow on nutrient agar

Leptospira habitat

obligate aerobes that are excreted in the urine of dogs and rodents

Leptospira significance

Leptospirosis

*septicemic phase

*Hepatic, Renal, and CNS involvement

* Weil's disease