Neisseria and Chlamydia Ken B. Waites, M.D., F(AAM)

Objectives To review and discuss microbiological characteristics epidemiology virulence factors associated diseases laboratory detection Of: Neisseria meningitidis Neisseria gonorrhoeae Chlamydia trachomatis Chlamydophila pneumoniae Chlamydophila psittaci

Neisseria meningitidis

N. meningitidis Oxidase positive Gram-negative diplococci Capnophilic (5 - 7% CO 2 ) Non-motile Grows on chocolate & sheep blood agar

The Meningococcal Cell Wall

N. meningitidis Pathogenesis Polysaccharide capsule Lipopolysaccharide (endotoxin) IgA protease

Nasopharynx Blood CSF (50%)

N. meningitidis Serotypes 13 serogroups based on polysaccharide capsule antigens –A, B and C > 90% of cases globally –A - epidemics in developing countries –B, C, and Y – sporadic and outbreaks in developed countries

Colony Morphology

Oxidase Positive

N. meningitidis Carbohydrate Metabolism

U.S: Leading cause of bacterial meningitis in older children and young adults –Community -sporadic –Institutional- outbreaks Afflicts approx. 2,800 persons per yr. in U.S. 10 – 15% mortality 11-19% have permanent sequelae Invasive disease can be fatal within hours Worldwide: Only form of meningitis that causes epidemics N. meningitidis Epidemiology

Humans – only reservoir Spread by respiratory droplets or oral secretions Nasopharyngeal colonization ~ 10-15%

N. meningitidis Risk Factors Household contact of primary case or carrier Crowding (boarding schools, military camps) Socioeconomic status Exposure to tobacco smoke Recent viral upper respiratory infection Asplenia Properdin or terminal complement deficiency

Meningococcal Disease Meningitis Bacteremia Meningococcemia (sepsis) Purpura fulminans Waterhouse - Friderichsen Syndrome Respiratory tract infection Focal infection Chronic meningiococcemia

Meningococcal Meningitis Clinical Symptoms Headache Stiff neck Photophobia Altered mental status Fever Nausea, vomiting Petechial or purpuric rash Pneumonia

Petechiae Purpura

Waterhouse – Friderichsen Syndrome

Neisseria meningitidis It’s bad – don’t get it!

Meningococcal Meningitis Prognosis Associated with fatal outcome:  Shock  Purpuric rash  Low or normal WBC  Age ≥ 60 yrs  Coma 10% of those who recover  Permanent neurologic disability  Hearing loss  Limb loss

Prevention of Meningococcal Disease Chemoprophylaxis after exposure Vaccination –New conjugate vaccine licensed in 2005

Recommended for:  U.S. military personnel  Children yrs  Persons at risk during outbreak  Travel to high risk area  College students  Asplenia  Complement deficiencies  Laboratory workers Meningococcal Vaccine

Vaccine Limitations No protection against Serogroup B  Polysialic capsule not immunogenic Not useful in children < 2 yrs 2 vaccines now available in US –MPSV4 – persons yrs –MCV4 – persons 2-10 yrs & > 55 yrs New conjugate vaccine MCV4 may –Provide longer immunity –Reduce carriage

Epidemiology of Major STDs in USA

Neisseria gonorrhoeae

Neisseria gonorrhoeae Characteristics Kidney-shaped Nonmotile Gram-negative diplococci Require specialized medium & incubation conditions for growth

N. Gonorrhoeae Pathogenesis Venereal or vertical transmission Pili enhance attachment to cells Opacity (opa) proteins in outer membrane facilitate cell invasion Endotoxin Peptidoglycan - tissue toxin Intracellular location IgA protease Antigenic variation -no permanent immunity following infection Penicillin resistance - plasmid & chromosomal

N. Gonorrhoeae Detection Gram stain of urethral discharge in male –Gram-negative diplococci in PMNs Culture – necessary in females –very susceptible to cold stress & drying –oxidase positive –glucose utilization –Requires CO 2 Nucleic Acid Amplification Chocolate agar + antibiotics (Thayer-Martin)

N. Gonorrhoeae Diseases Cervical/urethral gonorrhoea –20-30% likelihood of transmission Asymptomatic carriage - women Complications –arthritis –pelvic inflammatory disease –infertility –proctitis –pharyngitis –ophthalmia neonatorum male urethritis

Ophthalmia neonatorum Neonatal gonococcal or chlamydial ocular infection Acquired by passage through infected birth canal

Neisseria gonorrhoeae Prevention No effective vaccine Use of condoms Education Silver nitrate or antimicrobial drops in neonate eyes

Chlamydiatrachomatis Chlamydia trachomatis

Chlamydia trachomatis Characteristics Obligate intracellular pathogens Lacks peptidoglycan Unique intracytoplasmic growth cycle Depend on host for ATP Growth within cytoplasmic inclusion –prevents phagolysosome fusion Stain with Giemsa 15 serovars

Chlamydia Life Cycle

Chlamydia trachomatis Pathogenesis Ocular Infections: PMNs  monocytes  macrophages  plasma cells  lymphoid follicles  fibrosis, scarring Genital Infections: organism attached to mucosal epithelium induces inflammation & discharge Not as pyogenic as N. gonorrhoeae

Chlamydia trachomatis Detection Cell culture, stain inclusions with monoclonal antibodies Nucleic acid amplification (method of choice) Antigen detection - cheaper than nucleic amplification but less sensitive

Ocular Trachoma 400 million children & adults worldwide C. trachomatis serovars A, B, Ba, C Most common in developing countries Follicular keratoconjunctivitis

Neonatal Infections due to C. trachomatis Inoculation at birth from infected mothers –Inclusion keratoconjunctivitis –Pneumonitis

C. trachomatis Genital Disease in Adults Cervicitis in women Non-gonococcal urethritis in men One of the most common STDs Complications: infertility, ectopic pregnancy, salpingitis Many women asymptomatic

Lymphogranuloma Venereum Caused by C. trachomatis serovars L1,L1,L3 Inguinal lymphatic involvement with obstruction Much less common than chlamydial urethritis

Prevention of C. trachomatis Infections No effective vaccine No protective immunity following infections Improve socioeconomic & hygiene conditions Education

Chlamydophila psittaci Disease of parrots & parakeets sometimes transmitted to humans Respiratory infection (pneumonitis) Serologic diagnosis Transmitted in bird droppings

Chlamydophila pneumoniae New species (1980s) Acute lower respiratory illness, pharyngitis, sinusitis Similar to mycoplasma Frequently asymptomatic Detected by PCR, cell culture, serology Diagnostic testing not widely available Relation to other chronic inflammatory conditions such as atherosclerosis and coronary artery disease?