Neisseria gonorrhoeae: Drug Resistant Gonorrhea

Gonorrhea is a sexually transmitted disease (STD) caused by infection with the bacterium Neisseria gonorrhoeae. One of the most frequently reported infectious disease in the world, it has developed resistance to nearly all antibiotics used for treatment over the last 80 years. An estimated 820,000 infections occur in the US each year.

The Pathogen

Neisseria gonorrhoeae is a Gram negative, diplococcus shaped bacterium, that only colonizes humans. It is never present in normal flora, but has a high prevelance for disease with low mortality. N. gonorrhoeae infections start by the bacteria attaching to epithelial cells. The bacteria then penetrates the cell and multiplies inside. Bacterium inside the human cells produce an endotoxin called LOS, of which it can make many different types, that triggers an intense inflammatory response thoguht to be responsible for most of the symptoms of gonorrhea. The release of the LOS toxin does attract neutrophils who feed on the bacteria, but N. gonorrhoeae can survive inside the neutrophil. LOS can be released in "blebs", fragments of the bacteria's outer membrane released while the bacteria grows.

Gonorrhea the Disease

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N. gonorrhoeae infects and grows rapidly in mucous membranes, especially in the reproductive tract (cervix, uterus, fallopian tubes, rectum, and the urethra) but also the mucus membranes in the mouth, throat, and eyes. The bacteria is spread through sexual contact (vaginal, anal, and oral), or from mother to child at birth. Gonorrhea infections can happen to any sexually active person, but sometimes are asymptomatic, leading to up to 1/2 of all infections going unreported. Left untreated, gonorrhea infections can lead to serious health problems. Women whose infection spreads to the uterus or fallopian tubes causes pelvic inflammatory disease (PID), which can lead to chronic pelvic pain, internal abcesses, infertility, and ectopic pregnancies. Infected men who go untreated are at risk of epididymitis, which can lead to infertility. Untreated gonorrhea can also spread into the bloodstream and cause disseminated gonoccal infection (DGI), a potentially life threatening condition characterized by arthritus, tenosynovitis, and dermatitis. Gonorrhea infections also increase the risk of getting HIV and spreading HIV to others.

Antibiotic Resistant Gonorrhea

Gonorrhea has developed resistance to many antibiotics used for treatment, including sulfonamides, penicillins, tetracycline, and ciprofloxacin. 30% of reported infections are resistant to at least one drug. In 2006 there were 5 recommended treatment options, but now there is only one treatment option remaining due to resistance to the antibiotics that we used to use for treatment. The current (and last available) treatment is a dual aproach of azithromycin and ceftriaxone, but resistance is already being reported for both drugs. In Japan in 2008, a strain of gonorrhea was found to be resistant to all reccomended antibiotics, indicating that soon we will be without a treatment option.

 

Smarter than your average cocci 

Gonoccoci are known for "stealing" sialic acid from human cells and using it as a disguise from immune cells, who have sialic acid receptors. When immune cells interact with sialic acid coated bacteria, the immune response is dampened, allowing the bacteria a foothold into the body. CHARM Investigators have now discovered that gonorrhea doesn't need the sialic acid afterall, it has it's own protein that can bind the sialic acid receptors.

Read the article from Evolutionary Applications
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