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PYOGENIC COCCI Streptococcus Enterococcus Staphylococcus Neisseria

I. INTRODUCTION The Neisseria are Gram-negative diplococci approximately 0.6 to 0.8 mm in size The two pathogens in the genus Neisseria are Neisseria gonorrhoeae and Neisseria meningitidis

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"Of some significance in the..." Of some significance in the growth requirements of the 2 pathogens is a need for a CO2 enriched aerobic atmosphere These organisms are, therefore, capnophilic organisms

"The outer membrane of the..." The outer membrane of the pathogenic Neisseria contains lipooligosaccharide (LOS) and a series of proteins The LOS is analogous to the lipopolysaccharide (LPS) known as endotoxin in other Gram-negative organisms

"The lipid portion of the..." The lipid portion of the lipooligosaccharide is the principle bacterial toxin of the two pathogens in the genus

"Both of these species have..." Both of these species have pili They allow the organisms to adhere to the mucosal cell surfaces of the cervix, urethra, and nasopharynx

Laboratory Characteristics Nisengard says these organisms grow in chocolate agar Chocolate agar is heated blood agar that turns brown There is NO chocolate in chocolate agar

"Heating blood releases and denatures..." Heating blood releases and denatures many RBCs and serum proteins, making them more readily digestible to the bacteria These organisms also require other nutrients in the medium before they will grow

"Actually," Actually, N. meningitidis will grow on blood agar as well as the chocolate agar But N. gonorrhoeae will only grow on the chocolate agar

"All the neisserias are oxidase..." All the neisserias are oxidase positive The oxidase test tests for the oxidation of dimethylparaphenylene diamine Visually one sees a change from colorless to pink and then to dark purple The color change is seen in the colony itself Very few genera or species are oxidase positive

"SPECIES OXIDASE GROWTH PRODUCE" SPECIES OXIDASE GROWTH PRODUCE AT IgA 22OC PROTEASE N. meningitidis È – È N. gonorrhoeae È – È N. sicca È È – N. flavescens È È – N. subflava È È –

"FERMENTATIONS" FERMENTATIONS SPECIES GLUCOSE MALTOSE SUCROSE N. meningitidis È È – N. gonorrhoeae È – – N. sicca È È È N. flavescens – – – N. subflava È È V* * = variable

Neisseria gonorrhoeae

Gonococcal Infections The gonococci can cause several different infections Genital Gonorrhea is the most well known, but they can cause a pharyngitis, which is usually transmitted during oral sex

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Treatment of Gonococcal Infections Penicillin used to be the antibiotic of choice But many strains now produce penicillinase These are referred to as penicillinase producing Neisseria gonorrhoeae or PPNG Treatment of pharyngitis has been found to take longer than genital infections

Neisseria meningitidis

Meningococcal serology There are 9 serological types of meningococci based on capsular polysaccharides A few of these seem to be more involved in epidemic forms of meningitis than others There is also a noncapsular serotyping system based on proteins in the cell wall

Meningococcal infections N. meningitidis can exist in the nasopharynx of otherwise healthy humans Such individuals are called meningococcal carriers The meningococci are probably transferred by the respiratory route

"There are several forms of..." There are several forms of meningococcal disease that can range from a transient fever, to pharyngitis, to fulminant disease with death occurring within hours of the onset of clinical symptoms We’ve seen this occur around the country in the last couple of years

Treatment of Meningococcal Infections Penicillin is the treatment of choice

That’s it for Neisseria