Neisseria Species and Moraxella catarrhalis Overview

Neisseriaceae

Family including Neisseria, Kingella, Eikenella, Simonsiella, Alysiella.

Neisseria

Aerobic, capnophilic, gram-negative diplococci.

N. elongata

Catalase-negative, rod-shaped Neisseria species.

N. bacilliformis

Catalase-negative, rod-shaped Neisseria species.

N. weaveri

Catalase-positive, rod-shaped Neisseria species.

Normal flora

Non-pathogenic bacteria in upper respiratory, urogenital tracts.

N. meningitidis

Commensal inhabitant, can cause meningitis.

N. gonorrhoeae

Primary pathogen causing gonorrhea, only human host.

Gonorrhea

Acute pyogenic infection of urogenital tract, pharynx.

Disseminated infections

Less common infections from N. gonorrhoeae.

Public health issue

Gonorrhea is nationally reportable STD.

Chlamydia

Most reported STD, gonorrhea is second.

Ceftriaxone

Injectable cephalosporin for gonorrhea treatment.

Azithromycin

Oral antibiotic used in dual therapy.

Pili

Aid attachment, prevent phagocytosis, exchange genetic material.

Colony types

Five types: T1-T2 virulent, T3-T5 non-virulent.

Capsule

Virulence factor preventing phagocytosis.

Outer membrane proteins

Cause antigenic variation, useless antibody production.

Porin proteins

Major outer membrane proteins for nutrient transport.

por A and por B

Genes expressed in N. meningitidis, only por B in N. gonorrhoeae.

Sex pili

Transfer antibiotic resistance genes between bacteria.

Acute pyogenic infection

Infection characterized by pus formation.

Conjunctiva infection

Eye infection caused by N. gonorrhoeae.

Neisseria gonorrhoeae

Causative agent of gonorrhea, a sexually transmitted infection.

Virulence Factors

Characteristics that enhance pathogen's ability to cause disease.

Protein II (Opa)

Facilitates adherence to phagocytic and epithelial cells.

Protein III (Rmp)

Blocks host serum bactericidal action against Neisseria.

Lipooligosaccharides (LOS)

Major virulence factor, mediates tissue damage.

IgA protease

Cleaves IgA at mucosal surfaces, aiding infection.

Primary Infection Sites

Urethra, endocervix, anal canal, pharynx, conjunctiva.

Incubation Period

2 to 7 days before symptoms appear.

Male Symptoms

Dysuria, purulent discharge, often symptomatic.

Complications in Males

Epididymitis, urethral stricture, prostatitis.

Female Symptoms

Burning urination, vaginal discharge, abdominal pain.

Asymptomatic Females

50% of infections show no symptoms.

Complications in Females

Pelvic inflammatory disease, sterility, ectopic pregnancy.

Disseminated Gonococcal Disease

Acute form with fever, chills, and skin lesions.

Gonococcal Arthritis

Result of disseminated gonococcal bacteremia.

Ophthalmia Neonatorum

Eye infection in newborns from infected mothers.

Extragenital Infections

Includes pharyngitis and anorectal infections.

Anorectal Infection Rate

30%-60% of women with genital infection concurrent.

Laboratory Diagnosis

Requires specific media for isolation of Neisseria.

Specimen Collection

Proper techniques for urethral and endocervical samples.

Treatment for Neonates

Antimicrobial eye drops to prevent infection.

Pharyngitis Symptoms

Chief complaint in oropharyngeal infections.

Neisseria gonorrhoeae

Bacterial pathogen causing gonorrhea in humans.

Susceptibility to Drying

Neisseria is sensitive to drying and cold temperatures.

Direct Inoculation

Transfer to room temperature plate if possible.

Transport Media

Transgrow, JEMBEC, Amies used for specimen transport.

Capnophilic Atmosphere

Special media requiring increased CO2 levels.

Plating Time

Specimens should be plated within 6 hours.

Selective Media

Chocolate agar with inhibitors for unwanted flora.

Colony Morphology

Small, gray to tan, translucent colonies observed.

Incubation Temperature

Culture media incubated at 35°C with CO2.

Incubation Duration

Incubate for up to 72 hours.

Candle Extinction Jar

Used to maintain humidity during incubation.

BioBag CO2

Environmental chamber for CO2 incubation.

Gram-negative Intracellular Diplococci

Diagnostic feature in male urethral discharge.

Polymorphonuclear Neutrophils (PMN)

>5 PMN suggests nongonococcal urethritis.

Vaginal Commensal Microbiota

Resembles gonococci, complicating diagnosis in women.

Direct Gram Stain

Used to identify N. gonorrhoeae in specimens.

Oxidase Test

Identifies oxidase-positive bacteria using specific reagents.

Positive Oxidase Reaction

Purple color develops within 10 seconds.

Subculture Requirement

Colonies must be subcultured before oxidase testing.

Definitive Identification

Multiple methods used to confirm N. gonorrhoeae.

Demographic Profile

Consider patient demographics for testing methods.

Sensitivity and Specificity

Choose methods based on test accuracy.

Definitive Identification

Process of accurately identifying microorganisms.

Cystine Trypticase Agar (CTA)

Medium for traditional Neisseria identification.

Carbohydrate Utilization Test

Tests organism's ability to ferment carbohydrates.

Phenol Red

pH indicator used in carbohydrate tests.

Acid Production

Result of carbohydrate fermentation in tests.

N. gonorrhoeae

Only ferments glucose in carbohydrate tests.

Rapid Tests

Provide results in 2-4 hours for identification.

Preformed Enzymes

Enzymes present before bacterial growth in tests.

Weak Acid Production

Issue with some N. gonorrhoeae strains.

Misidentification

Incorrectly identifying N. subflava as N. meningitidis.

Chromogenic Methods

Detect enzymes producing colored end products.

Selective Media

Inhibits nonpathogenic species to avoid false positives.

Multitest Methods

Combines enzyme tests with biochemical tests.

N. meningitidis

Ferments glucose and maltose in tests.

Coagglutination

Uses monoclonal antibodies for identifying N. gonorrhoeae.

Fluorescent Antibody Testing

Uses fluorescent tags for pathogen identification.

MALDI-TOF MS

Identifies pathogens by unique protein signatures.

Ionization Process

Vaporizes proteins for mass spectrometry analysis.

Nucleic Acid Assays

Rapid tests for detecting genetic material.

False Positives

Incorrect positive results due to contamination.

Nonamplified Probe Test

Marginally sensitive compared to cervical culture.

Low Prevalence Populations

Non-culture methods unsuitable for children or abuse cases.

Selective Gonococcal Media

Cultures specimens for accurate gonococcus identification.

Biochemical Procedures

Two different tests recommended for definitive ID.

Nucleic Acid Assays

Tests detecting DNA or RNA in samples.

Advantages

Benefits of nucleic acid assays include rapid results.

Sensitivity

Ability to detect low levels of target nucleic acids.

Urine Samples

Nucleic acid assays can utilize urine for testing.

Nonamplified Probe Test

Marginally more sensitive than cervical culture.

FDA Approval

Not approved for pharyngeal or rectal specimens.

Susceptibility Testing

Recovery of organisms for testing is not possible.

Children and Sexual Abuse Cases

Nucleic acid assays cannot be used in these cases.

False Positives

Result from laboratory cross-contamination of nucleic acids.