Neisseria gonorrhoeae vs Neisseria meningitidis Differences...

            Neisseria gonorrhoeae and Neisseria                                              meningitidis Difference

 keerthi Vasan R.

Neisseria meningitidis and Neisseria gonorrhoeae, are obligate human pathogens that cause distinctly different disease syndromes. They are both Gram negative diplococci, non-sporing, oxidase positive and difficult to differentiate on morphological and cultural characteristics.

 

What is Neisseria gonorrhoeae:

Gonorrhea is a sexually transmitted disease (STD) caused by infection with the Neisseria gonorrhoeae bacterium. N. gonorrhoeae infects the mucous membranes of the reproductive tract, including the cervix, uterus, and fallopian tubes in women, and the urethra in women and men. N. gonorrhoeae can also infect the mucous membranes of the mouth, throat, eyes, and rectum.

 

What is Neisseria meningitidis:

Meningococcal disease is caused by bacteria called Neisseria meningitidis. People with meningococcal disease spread the bacteria to others through close personal contact such as living together or kissing. A person with meningococcal disease needs immediate medical attention.

 

Genaral Characteristic:

Character	Neisseria gonorrhoeae	Neisseria meningitidis
Gram staining	Gram negative	Gram negative
Shape	Diplococci	Diplococci
Endospores	Non-sporing	Non-sporing
Grouping	Strains characterized by auxotyping which recognizes reqiurements for specific nutrients.	Serogroup is determined by its lipopolysaccharide capsular antigen.

 

Other Characteristic:

 

Character	Neisseria gonorrhoeae	Neisseria meningitidis
Commonly Called	Gonococcus	Meningococcus
Cell Morphology	Kidney shaped with apposing ends concave.	Semicircular diplococcus with flat apposing ends.
Capsule	Absent	Capsule is present which is anti-phagocytic and an important virulence factor.
Pili	Most often moves using one retracting pilus.	Most often move using four pili.
Movement	Movement of N. gonorrhoeae occurs at lower speed.	Movement of N. meningitidis occurs faster with a larger number of retracting pili.
Fastidious	Most fastidious among Neisseria spp.	Comparatively less fastidious.
Pathogen	It is always a pathogen.	It may or may not be pathogenic.
Form	Predominantly exist in intracellular form	Exist in both intra· and extracellular forms
Plasmids	Usually possess plasmids, coding for drug resistant genes.	Rarely have plasmids
Superbug	Considered as “superbug	Not considered as “superbug”

Human Infection:

 

Character	Neisseria gonorrhoeae	Neisseria meningitidis
Normal Flora	Not considered as normal flora.	Many normal individuals may harbor Neisseria meningitidis in the upper respiratory tract
Virulence Factors	Pili, IgA proteases and production of lipopolysaccharide endotoxin.	LPS capsule, IgA protease and iron utilizationfrom transferrin.
Disease	Male: urethritis, proctitis Female: endocervicitis, PID (contiguous spread), arthritis, proctitis Infants: ophthalmia neonatorum Otitis media Sinusitis Bronchitis and bronchopneumonia in elderly patients with COPD	Meningitis and meningococcemia
Portal of Entry	Genital	Respiratory
Related Conditions	N. gonorrhoeae can also cause conjunctivitis, pharyngitis, proctitis or urethritis, prostatitis, and orchitis.	Cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis.

Lab Diagnosis:

Character	Neisseria gonorrhoeae	Neisseria meningitidis
Specimens	Transport swab of endocervix, urethra, rectum, pharynx, conjunctiva, blood, joint fluid, aspirates from skin lesions.	Cerebrospinal fluid (CSF) and blood, swab skin lesions and nasopharynx.
Culture medium	Contain antimicrobials that inhibit the growth of organisms other than N. gonorrhoeae; typically vancomycin (inhibits Gram-positive bacteria), colistin (inhibits gram-negative bacteria including the commensal Neisseria spp.), trimethoprim (inhibits swarming of Proteus spp.) and nystatin or amphotericin B (antifungal agents).	Blood agar, trypticase soy agar, supplemented chocolate agar, and Mueller-Hinton agar.
Growth on Blood Agar	N. gonorrhoeae grow less well on blood agar than N. meningitidis.	N. meningitidis grow well on blood agar than N.  gonorrhoea
Growth Rate	Slower than Meningococcus	Slow
Sugar Fermentation	Produce acid from glucose only	Produce acid from glucose and maltose.
Maltose Fermentation	No	Yes
Nitrite Reduction	N. gonorrhoeae doesn’t reduce nitrites.	N. meningitidis can reduce nitrites in low concentrations.
Autolysis	May autolyse	Autolyse
Glutamylaminotransferase	Non-producer	Producer
Β-Lactamase Production	Common	Rare

Treatment:

Character	Neisseria gonorrhoeae	Neisseria meningitidis
Vaccines	No	Serogroup A, B, C, Y and W-135 meningococcal infections can be prevented by vaccines.
Antibiotics	Ceftriaxone  given as an injection  with oral azithromycin (Zithromax).	Rifampin, ciprofloxacin, and ceftriaxone
Prevalence and Mortality	N.gonorrhoeae infections have a high prevalence and low mortality.	N. meningitidis infections have a low prevalence and high mortality.