1 Chlamydia and Spirochetes Nicole Luke-Marshall, Ph.D. [email protected] February 19, 2014 MIC 301 Today’s Lecture Topics 1. Chlamydia § Chlamydia trachomatis – causative agent of STI chlamydia 2. Spirochetes § Treponema pallidum – causative agent of STI syphilis § Borrelia burgdorferi – causative agent of Lyme disesase But 1st, a brief overview of Sexually Transmitted Infections (STIs)… STIs § Sexually transmitted infections (STIs) (also known as sexually transmitted diseases (STDs) or venereal diseases (VD)) are infections that are commonly spread from person to person through unprotected intimate contact. § While in the past, these illnesses have mostly been referred to as STDs or VD, the term STI has become preferred: a person may be ‘infected’ and may potentially infect others without showing signs of ‘disease’. § STIs can affect males and females of all ages and backgrounds who are engaging in sexual contact, including vaginal, oral, and anal sex. § Some STIs can also be transmitted via the sharing of needles (IVDA, medical, tattoo) as well as through childbirth or breastfeeding. STIs Today § ~20 million new STI infections reported annually in the US (CDC). § > 1 million people acquire a STI every day worldwide (WHO) § STIs often give no warning signs or symptoms. You can get infected and infect a sexual partner without knowing it and serious complications can progress silently and cause irreversible damage before you ever recognize a problem. § The true incidence of STIs is vastly under-estimated. o Although cases of chlamydia, syphilis and gonorrhea are reported to health departments, other STIs (including HPV and genital herpes) are not. o Also, a large proportion of infections are asymptomatic. § "STIs are one of the most critical health challenges facing the nation today.” Centers for Disease Control and Prevention (CDC), 2011. • Young adults between the ages of 15 to 24 represent only 25% of the sexually active population but account for nearly half of all STI diagnoses each year. • Every day in the U.S. it’s estimated ~12,000 15 to 24 year olds contract a STI! o A female is four times more likely to contract an STI than she is to become pregnant following unprotected sex. Sexually transmitted infections (STIs) cannot live long enough on a toilet seat to be transmissible.2 Chlamydia trachomatis Disease: Chlamydia Chlamydia 1. Chlamydiae are obligate intracellular bacteria § depend on the host cell for survival and replication 2. The Chlamydiae consist of 3 species; all cause human disease: § C. trachomatis – causes ocular and genital infections § C. pneumoniae – causes outbreaks of respiratory tract infections, spreads from person to person § C. psittaci – transmitted from infected birds or animals to humans through the respiratory tract, causes an influenza-like illness called psittacosis Chlamydia trachomatis Four important points to remember: 1. Chlamydia (STI) and trachoma (eye disease) are caused by the Gram-negative bacteria Chlamydia trachomatis. 2. C. trachomatis is naturally found living only inside human cells. 3. One of the most common treatable STIs worldwide (>95 million cases/yr) o The most reported communicable disease in the US (>1.3 million cases/yr) 4. The single most important infectious agent associated with blindness o Approximately 600 million worldwide suffer C. trachomatis eye infections and 20 million are blinded as a result of the infection. Chlamydia trachomatis are intracellular bacteria. Colored transmission electron micrograph (TEM) of Chlamydia trachomatis (pink/black) inside a cell (brown/). These bacteria live only inside cells. Chlamydia Transmission and Prevalence § Chlamydia can be transmitted during vaginal, anal, or oral sex, and can be passed from an infected mother to her baby during childbirth § Chlamydia infection is the most common STI in the US • Although >1.3 million US cases per year are reported, it is estimated that > 3 million people are actually infected due to a high incidence of asymptomatic infections. § Chlamydia is known as the "Silent Epidemic" because in ~75% of cases in women it may not cause any symptoms • Of those who have an asymptomatic infection that is not detected, ~50% will develop pelvic inflammatory disease (PID) • PID can cause scarring inside the reproductive organs, which cause serious complications, including chronic pelvic pain, infertility, ectopic (tubal) pregnancy. Symptoms of Chlamydia Infection Symptoms in MEN: § As many as 1 in 4 men with chlamydia have no symptoms. § Chlamydia may produce symptoms similar to gonorrhea and may include: o Burning sensation during urination o Discharge from the penis or rectum o Testicular tenderness or pain o Rectal discharge or pain3 Symptoms of Chlamydia Infection Symptoms in WOMEN: § As many as 3 in 4 women with chlamydia have no symptoms. § Symptoms that may occur in women include: o Burning sensation during urination o Painful sexual intercourse o Vaginal discharge or bleeding after intercourse o Rectal discharge or pain o Abdominal or lower back pain o Liver inflammation similar to hepatitis o Symptoms of pelvic inflammatory disease (PID) 1. Generic term for inflammation of the uterus, fallopian tubes, &/or ovaries that leads to scar formation on nearby tissues and organs 2. Bacteria ascend the reproductive tract infecting and causing inflammation of the uterus, fallopian tubes, and ovaries and destroy the mucosa 3. PID-scarring often causes permanent damage • Ectopic pregnancy and other dangerous pregnancy complications • Severe, chronic abdominal and pelvic pain 4. Infertility • PID directly responsible for 100,000 cases sterility per yr in U.S. • 12-20% of women become sterile after 1 episode (50% after 3) Pelvic Inflammatory Disease (PID) Complications of Chlamydia Infection § Untreated chlamydial infections can cause serious reproductive and other health problems with both short-term and long-term consequences. o PID (women): Chlamydia causes 250,000 - 500,000 PID cases/year in the US o sterility (men and women) o blindness (men, women, infants) o lymphogranuloma venereum, an infection of