Question

15.Explain the clinical and laboratory finding of bacterial disease including Lyme disease, Streptococcal, Syphilis and Mycoplasma.

Answer 1

1.Lyme disease:-

  

Lyme disease is transmitted to humans by the bites of infected ticks of the genus Ixodes. In the United States, ticks of concern are usually of the Ixodes scapularis type, and must be attached for at least 36 hours before the bacteria can spread. In Europe ticks of the Ixodes ricinus type may spread the bacteria more quickly. In North America, Borrelia burgdorferi and Borrelia mayonii are the cause. In Europe and Asia, the bacteria Borrelia afzelii and Borrelia garinii are also causes of the disease. The disease does not appear to be transmissible between people, by other animals, or through food.Diagnosis is based upon a combination of symptoms, history of tick exposure, and possibly testing for specific antibodies in the blood. Blood tests are often negative in the early stages of the disease. Testing of individual ticks is not typically useful.

Prevention includes efforts to prevent tick bites such as by wearing clothing to cover the arms and legs, and using DEET-based insect repellents.Using pesticides to reduce tick numbers may also be effective.Ticks can be removed using tweezers. If the removed tick was full of blood, a single dose of doxycycline may be used to prevent development of infection, but is not generally recommended since development of infection is rare.If an infection develops, a number of antibiotics are effective, including doxycycline, amoxicillin, and cefuroxime. Standard treatment usually lasts for two or three weeks.Some people develop a fever and muscle and joint pains from treatment which may last for one or two days. In those who develop persistent symptoms, long-term antibiotic therapy has not been found to be useful.

Lyme disease is the most common disease spread by ticks in the Northern Hemisphere.It is estimated to affect 300,000 people a year in the United States and 65,000 people a year in Europe. Infections are most common in the spring and early summer. Lyme disease was diagnosed as a separate condition for the first time in 1975 in Old Lyme, Connecticut. It was originally mistaken for juvenile rheumatoid arthritis. The bacterium involved was first described in 1981 by Willy Burgdorfer. Chronic symptoms following treatment are well described and are known as "post-treatment Lyme disease syndrome" (PTLDS). PTLDS is different from chronic Lyme disease; a term no longer supported by the scientific community and used in different ways by different groups.Some healthcare providers claim that PTLDS is caused by persistent infection, but this is not believed to be true because no evidence of persistent infection can be found after standard treatment. A vaccine for Lyme disease was marketed in the United States between 1998 and 2002, but was withdrawn from the market due to poor sales.Research is ongoing to develop new vaccines.

In the absence of an EM rash or history of tick exposure, Lyme diagnosis depends on laboratory confirmation. The bacteria that cause Lyme disease are difficult to observe directly in body tissues and also difficult and too time-consuming to grow in the laboratory. The most widely used tests look instead for presence of antibodies against those bacteria in the blood. A positive antibody test result does not by itself prove active infection, but can confirm an infection that is suspected because of symptoms, objective findings, and history of tick exposure in a person. Because as many as 5-20% of the normal population have antibodies against Lyme, people without history and symptoms suggestive of Lyme disease should not be tested for Lyme antibodies: a positive result would likely be false, possibly causing unnecessary treatment.

In some cases, when history, signs, and symptoms are strongly suggestive of early disseminated Lyme disease, empiric treatment may be started and reevaluated as laboratory test results become available.

2.streptococcal:-

Group A streptococcal disease (GAS) is caused by a bacteria called Streptococcus pyogenes, group A.

Most often, group A streptococcal infections are mild illnesses such as “strep throat” or impetigo.

Sometimes, the bacteria invade the lungs, blood, or spread along the layers of tissue that surround muscle. These infections are called invasive group A streptococcal (iGAS) disease and are very serious, even life-threatening.

Streptococcal bacteria are highly contagious. They can spread through airborne droplets when someone with the infection coughs or sneezes, or through shared food or drinks. You can also pick up the bacteria from a doorknob or other surface and transfer them to your nose, mouth or eyes.

3.syphills:-

Syphilis is a sexually transmitted infection (STI) caused by a type of bacteria known as Treponema pallidum.

The first sign of syphilis is a small, painless sore. It can appear on the sexual organs, rectum, or inside the mouth. This sore is called a chancre. People often fail to notice it right away.

Syphilis can be challenging to diagnose. Someone can have it without showing any symptoms for years. However, the earlier syphilis is discovered, the better. Syphilis that remains untreated for a long time can cause major damage to important organs, like the heart and brain.

Syphilis is only spread through direct contact with syphilitic chancres. It can’t be transmitted by sharing a toilet with another person, wearing another person’s clothing, or using another person’s eating utensils.

The four stages of syphilis are:

-primary
-secondary
-latent
-tertiary
Syphilis is most infectious in the first two stages.

When syphilis is in the hidden, or latent, stage, the disease remains active but often with no symptoms. Tertiary syphilis is the most destructive to health.

Primary and secondary syphilis are easy to treat with a penicillin injection. Penicillin is one of the most widely used antibiotics and is usually effective in treating syphilis. People who are allergic to penicillin will likely be treated with a different antibiotic, such as:

-doxycycline
-azithromycin
-ceftriaxone
If you have neurosyphilis, you’ll get daily doses of penicillin intravenously. This will often require a brief hospital stay. Unfortunately, the damage caused by late syphilis can’t be reversed. The bacteria can be killed, but treatment will most likely focus on easing pain and discomfort.

During treatment, make sure to avoid sexual contact until all sores on your body are healed and your doctor tells you it’s safe to resume sex. If you’re sexually active, your partner should be treated as well. Don’t resume sexual activity until you and your partner have completed treatment.

4.mycoplasma:-

Mycoplasma (plural mycoplsasmas or mycoplasmata) is a genus of bacteria that lack a cell wall around their cell membranes.This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis (like the beta-lactam antibiotics). They can be parasitic or saprotrophic. Several species are pathogenic in humans, including M. pneumoniae, which is an important cause of "walking" pneumonia and other respiratory disorders, and M. genitalium, which is believed to be involved in pelvic inflammatory diseases. Mycoplasma species are the smallest bacterial cells yet discovered,can survive without oxygen, and come in various shapes. For example, M. genitalium is flask-shaped (about 300 x 600 nm), while M. pneumoniae is more elongated (about 100 x 1000 nm). Hundreds of mycoplasma species infect animals.

Mycoplasma species are often found in research laboratories as contaminants in cell culture. Mycoplasmal cell culture contamination occurs due to contamination from individuals or contaminated cell culture medium ingredients. Mycoplasma cells are physically small – less than 1 µm, so are difficult to detect with a conventional microscope.

Mycoplasmae may induce cellular changes, including chromosome aberrations, changes in metabolism and cell growth. Severe Mycoplasma infections may destroy a cell line. Detection techniques include DNA probe, enzyme immunoassays, PCR, plating on sensitive agar and staining with a DNA stain including DAPI or Hoechst.