Bacterii, infecții

What are Bacteria?







Bacteria are microscopic, single-cell organisms that live almost everywhere. Bacteria live in every climate and location on earth. Some are airborne while others live in water or soil. Bacteria live on and inside plants, animals, and people. The word "bacteria" has a negative connotation, but bacteria actually perform many vital functions for organisms and in the environment. For example, plants need bacteria in the soil in order to grow.


The vast majority of bacteria are harmless to people and some strains are even beneficial. In the human gastrointestinal tract, good bacteria aid in digestion and produce vitamins. They also help with immunity, making the body less hospitable to bad bacteria and other harmful pathogens. When considering all the strains of bacteria that exist, relatively few are capable of making people sick.



What Is a Bacterial Infection?







A bacterial infection is a proliferation of a harmful strain of bacteria on or inside the body. Bacteria can infect any area of the body. Pneumonia, meningitis, and food poisoning are just a few illnesses that may be caused by harmful bacteria. Bacteria come in three basic shapes: rod-shaped (bacilli), spherical (cocci), or helical (spirilla). Bacteria may also be classified as gram-positive or gram-negative. Gram-positive bacteria have a thick cell wall while gram-negative bacteria do not. Gram staining, bacterial culture with antibiotic sensitivity determination, and other tests are used to identify bacterial strains and help determine the appropriate course of treatment.



Bacteria vs. Virus







Bacteria and viruses are different types of pathogens, organisms that can cause disease. Bacteria are larger than viruses and are capable of reproducing on their own. Viruses are much smaller than bacteria and cannot reproduce on their own. Instead, viruses reproduce by infecting a host and using the host's DNA repair and replication systems to make copies of itself.


The symptoms of a bacterial or viral infection depend on the area of the body that is affected. Sometimes the symptoms of the two can be very similar. For example, runny nose, cough, headache, and fatigue can occur with the common cold (virus) and with a sinus infection (bacteria). A doctor may use the presence of other symptoms (such as fever or body aches), the length of the illness, and certain lab tests to determine if an illness is due to a virus, bacteria, or some other pathogen or disease process.



Bacterial Skin Infections







Bacterial skin infections are usually caused by gram-positive strains of Staphylococcus and Streptococcus or other organisms. Common bacterial skin infections include:


Cellulitis causes a painful, red infection that is usually warm to the touch. Cellulitis occurs most often on the legs, but it can appear anywhere on the body.






Folliculitis is an infection of the hair follicles that causes red, swollen bumps that look like pimples. Improperly treated pools or hot tubs can harbor bacteria that cause folliculitis.






Impetigo causes oozing sores, usually in preschool-aged children. The bullous form of impetigo causes large blisters while the non-bullous form has a yellow, crusted appearance.






Boils are deep skin infections that start in hair follicles. Boils are firm, red, tender bumps that progress until pus accumulates underneath the skin.




Bacterial skin infections are treated with oral or topical antibiotics depending on the strain causing the infection.



Foodborne Bacterial Infections







Bacterial infections are one cause of foodborne illness. Nausea, vomiting, diarrhea, fever, chills, and abdominal pain are common symptoms of food poisoning. Raw meat, fish, eggs, poultry, and unpasteurized dairy may harbor harmful bacteria that can cause illness. Unsanitary food preparation and handling can also encourage bacterial growth. Bacteria that cause food poisoning include:


Campylobacter jejuni (C. jejuni) is a diarrheal illness often accompanied by cramps and fever.






Clostridium botulinum (C. botulinum) is a potentially life-threatening bacterium that produces powerful neurotoxins.






Escherichia coli (E. coli) O157:H7 is a diarrheal (often bloody) illness that may be accompanied by nausea, vomiting, fever, and abdominal cramps.






Listeria monocytogenes (L. monocytogenes) causes fever, muscle aches, and diarrhea. Pregnant women, elderly individuals, infants, and those with weakened immune systems are most at risk for acquiring this infection.






Salmonella causes fever, diarrhea, and abdominal cramps. Symptoms typically last between 4 and 7 days.






Vibrio causes diarrhea when ingested, but it can also cause severe skin infections when it comes in contact with an open wound.






Sexually Transmitted Bacterial Infections







Many sexually transmitted diseases (STDs) are caused by harmful bacteria. Sometimes, these infections aren't associated with any symptoms but can still cause serious damage to the reproductive system. Common STDs caused by bacterial infections include:


Chlamydia is an infection in men and women caused by an organism called Chlamydia trachomatis. Chlamydia increases the risk of pelvic inflammatory disease (PID) in women.






Gonorrhea, also known as "clap" and "the drip," is caused by Neisseria gonorrhoeae. Men and women can be infected. Gonorrhea also increases the risk of pelvic inflammatory disease (PID) in women.






Syphilis can affect men and women and is caused by the bacteria Treponema pallidum. Untreated, syphilis is potentially very dangerous and can even be fatal.






Bacterial vaginosis, which causes an overgrowth of pathogenic bacteria in the vagina (the CDC does not consider this a STD; see second text reference).






Other Bacterial Infections







Harmful bacteria can affect almost any area of the body. Other types of bacterial infections include:


Bacterial meningitis is a severe infection of the meninges, the lining of the brain.






Otitis media is the official name for an infection or inflammation of the middle ear. Both bacteria and viruses can cause ear infections, which commonly occur in babies and small children.






Urinary tract infection (UTI) is a bacterial infection of the bladder, urethra, kidneys, or ureters.






Respiratory tract infections include sore throat, bronchitis, sinusitis, and pneumonia. Bacteria or viruses may be responsible for respiratory tract infections. Tuberculosis is a type of bacterial lower respiratory tract infection.






Antibiotics







Antibiotics are medications that fight bacterial infections. They work by disrupting the processes necessary for bacterial cell growth and proliferation. It's important to take antibiotics exactly as prescribed. Failure to do so could make a bacterial infection worse. Antibiotics don't treat viruses, but they're sometimes prescribed in viral illnesses to help prevent a "secondary bacterial infection." Secondary infections occur when someone is in a weakened or compromised state due to an existing illness.



Antibiotic Resistance







Overuse and misuse of antibiotics has led to a rise in antibiotic resistance. Antibiotic resistance occurs when bacteria are no longer sensitive to a medication that should eliminate an infection. Antibiotic-resistant bacterial infections are potentially very dangerous and increase the risk of death. About 2 million people in the U.S. suffer from antibiotic resistant infections each year and 23,000 die due to the condition. The CDC estimates 14,000 deaths alone are due to Clostridium difficile (C. difficile) infections that occur because of antibiotic suppression of other bacteria allow C.difficile to proliferate. Most deaths due to antibiotic resistant infections occur in hospitalized patients and those who are in nursing homes.



Good Bacteria and Probiotics







Beneficial bacteria live in the human gastrointestinal (GI) tract and play an important role in digestion and immunity. Most people know it's smart to eat yogurt after completing a course of antibiotics to repopulate the GI tract with helpful bacteria that were wiped out from the antibiotics.


Some studies have shown probiotics can shorten the duration of infectious diarrhea. They may also reduce the risk of developing diarrheal illness due to antibiotic use. Probiotics seem to reduce gas, bloating, and abdominal pain associated with irritable bowel syndrome (IBS). Ongoing research seeks to determine the types and dosages of bacteria that are most beneficial to human health.


What Is a Staph Infection? Symptoms, Pictures


Reviewed By: Physicians' Review Network (PRN)




Reviewed on 7/27/2016



What Is Staphylococcus?







Staphylococcus is a type of bacteria that can cause many types of infections in your body. Commonly referred to as Staph (pronounced "staff"), it is common bacteria found on most people's skin, and often it does not cause disease. More than 30 types of Staphylococci bacteria cause infections, but the most common type of Staph infection is caused by Staphylococcus aureus. If the bacteria gains access to the body, either through a wound on the skin or via the respiratory tract, it can cause serious infections.



Who Is at Risk for Staph Infections?







While anyone can get a Staph infection, some conditions put people at higher risk including:






What Are the Signs and Symptoms of a Staph Infection?







Symptoms of staphylococcal disease of the skin include pus-filled abscesses (also called boils or furuncles). Pain, swelling, and redness in the area of the infection is common, along with drainage of pus. If the staph infection is in the blood (called bacteremia or sepsis) symptoms can include fever, chills, and low blood pressure (hypotension).



What Types of Diseases Are Caused by Staph?







Staphylococcus causes many different types of infections. Most of the infections cause localized inflammation or pockets of infection known as abscesses. Superficial skin infections such as impetigo (a crusting of the skin) or cellulitis (an infection of the skin layers) are the most common. Breastfeeding women can get a staph infection of the breast called mastitis, which can release bacteria into the mother's milk. Staph bacteria in the lungs can cause pneumonia. When a Staph infection gets into the bone it can cause osteomyelitis. Staph infection in the blood can also infect the heart or heart valves (endocarditis). If the Staph infection gets into the bloodstream it can spread to other organs and cause severe and life-threatening infections (bacteremia or sepsis). Sepsis can lead to shock or multi-organ failure, which can rapidly lead to death.



What Is Antibiotic-Resistant Staph aureus?







Methicillin-resistant Staphylococcus aureus, or MRSA, is a type of staph resistant to antibiotics, including methicillin, penicillin, amoxicillin, and oxacillin. MRSA is considered a type of "superbug," because it has become resistant to antibiotics commonly used to treat it. MRSA has been found to cause illness in hospitals, nursing homes, prisons and other health facilities called (health-care-associated MRSA or HA-MRSA). It has also caused infections outside of healthcare facilities, called community-associated MRSA (CA-MRSA).



What Are Complications of Staph Infections?







Skin infections with Staph bacteria can cause a serious condition called scalded skin syndrome, which is seen more often in children, but can occur in adults as well. The infection causes a breakdown of the upper layers of the skin, which blisters and sloughs off (just like a severe burn). When the infection covers a large surface area of the body, the result can be fatal. Scalded skin syndrome is treated with intravenous antibiotics and fluids to prevent dehydration.



What Is Staph Food Poisoning?







People can get Staph food poisoning by eating foods contaminated with the Staphylococcus aureus (S. aureus) bacterium. The bacterium releases a toxin into the foods, causing a rapid onset of severe nausea and vomiting. It may also cause fever. Foods most associated with Staphylococcus food poisoning are eggs, meats, poultry, salads (egg, tuna, chicken, potato, macaroni), cream-filled baked goods, and dairy products.



How Are Staph Infections Diagnosed?







A doctor may diagnose a minor staphylococcal skin infection by examination of the skin and lab tests are not usually needed. Serious Staph infections of the blood, pneumonia, or endocarditis (inflammation of the inner chambers of the heart) usually require cultures (samples of blood, pus, or tissues grown in the lab to confirm the presence of the Staphylococcus bacterium). Once the Staph bacteria is confirmed, another test called a sensitivity test can be run to see which antibiotics will kill the bacteria.



What Does Staphylococcus aureus Bacteria Look Like?







Under the power of a highly magnified microscope, Staphylococcus aureus appears as small, round organisms arranged in clusters (like clusters of grapes). There are thread-like connections between the round bacterium made of "biofilm." This biofilm helps protect the bacteria and increases its chances of causing infections.



How Are Staph Infections Treated?







Treatment for Staph infections depends on the location and severity of the infection. Minor skin infections can be treated with topical antibiotic ointments, or oral antibiotics. Abscesses are generally treated with incision and drainage or surgery. More severe infections in large areas of the skin, other body organs, or the bloodstream are generally treated with intravenous antibiotics. MRSA infections may be resistant to many antibiotics.



Can Staph Infections Be Prevented?







There is no vaccine currently available to prevent Staphylococcus aureus. Preventing Staph remains the best defense against contracting an infection. Ways to help manage risk factors for contracting Staph and MRSA are discussed on the following slides.



Staph Prevention Tip #1







Cover all skin Staph infections with clean, dry bandages. This is especially important if the wounds are producing pus and draining, because the pus may contain MRSA, which can spread to others.



Staph Prevention Tip #2







Proper hygiene is important. Wash hands diligently, avoid close contact with infected individuals, and carefully clean all skin scrapes, cuts, and wounds to reduce the chances of them becoming infected with Staph. If you have Staph, make sure all people in close contact with you wash their hands frequently, especially if they change your bandages or touch the infected wound.



Staph Prevention Tip #3







Do not share personal items that may have come in contact with the infected wound. Items such as towels, razors, bed linens, or clothing should not be shared. Wash all bedding and clothing in hot water, and dry in a hot dryer to help kill Staph bacteria.



Staph Prevention Tip #4







Handle and prepare food safely to help decrease the risk of Staphylococcal food poisoning:


Wash hands thoroughly with soap and water before handling and preparing food.






If you have wounds, skin infections, or a nose or eye infection, do not prepare or serve food to others.






Clean and sanitize kitchens and all dining areas.






Keep hot foods hot (over 140 F) and cold foods cold (40 F or under).






Refrigerate any food that is to be stored as soon as possible.






Staph Prevention Tip #5







The risk of developing toxic shock syndrome (a rare, life-threatening illness caused by toxins secreted by Staph bacteria and associated with tampon use, especially when tampons are not changed frequently) in menstruating women can be reduced by:


Changing tampons every 4 to 8 hours






Using low-absorbency tampons






Alternating tampon use with sanitary pads






Staph Prevention Tip #6







If you have a Staph or MRSA infection, tell your doctor or any health care provider you visit so they can take the proper protective precautions.



Staph Infection Prognosis







When mild and promptly treated with antibiotics, the prognosis for recovery from a Staph infection is excellent. However, a MRSA infection can have an entirely different outlook. MRSA infections, when mild and found in otherwise healthy individuals have a relatively good prognosis. MRSA infections in chronically or severely ill people, the elderly, newborns, or other people with compromised immune systems may be life-threatening or fatal.



Staph Infection At A Glance







Staphylococcus, is bacteria that can cause many types of infections.






Staphylococcus can cause diseases such as abscesses, impetigo, food poisoning, cellulitis, mastitis, scalded skin syndrome, and toxic shock syndrome.






MRSA, or methicillin-resistant Staphylococcus aureus, is a type of Staph infection resistant to many different antibiotics.






Staph infections are treated with topical, oral, or intravenous antibiotics, depending upon the type and severity of the infection.






MRSA Infection: Causes, Symptoms, and Treatment


Reviewed By: Physicians' Review Network (PRN)




Reviewed on 5/3/2016



What is MRSA?







Methicillin-resistant Staphylococcus aureus (MRSA) are shown in this scanning electron microscope picture. Strains of these bacteria (commonly termed "staph") may cause infection in almost any part or organ system in humans. MRSA strains are further characterized as superbugs because MRSA strains are resistant to many different antibiotics



Symptoms of a MRSA Skin Infection







Initially, MRSA infections in the skin resemble minor skin infections; they appear as a red bump, pimple, or boil on the skin that may be painful, swollen, or warm to the touch. Occasionally, these infections may open and have pus drain from the area. Although most MRSA skin infections are mild, some progress and spread further into the skin and to other areas or organ systems.



Is It MRSA, a Spider Bite, or Something Different?







Bug bites, insect bites, spider bites, rashes, and stings are often difficult to distinguish from MRSA infections because they have similar appearances or symptoms. However, if the person never viewed a spider or other entity causing the lesion, there is a good chance the skin lesion may be caused by MRSA, especially if the lesion area spreads or does not start getting better after about two to three days of treatment with common antibiotics.



MRSA Skin Infection and Cellulitis







Often, the first indication of MRSA infection is a spread of the infection into the surrounding skin, producing skin that is pink or reddish and often is warm, tender, and swollen. Such an infected skin area is termed cellulitis and represents infection spread into deeper skin layers. Cellulitis can rapidly advance (over a few hours) in some individuals.



MRSA Skin Infection: Abscess







MRSA may be somewhat contained by the body by attempting to wall off the invading bacteria by making a pocket of pus surrounded by cells trying to kill or stop the MRSA from advancing. This deeper skin infection is termed an abscess and can spread like cellulitis in some instances. Abscesses usually require drainage (sometimes done with warm compresses, sometimes with a needle, while others require surgical drainage) and antibiotics; your doctor should be consulted as you should not attempt to treat MRSA infections by yourself.



How Do People Catch MRSA?







MRSA is easily spread to other individuals by people with the organisms on their skin. Usually, either skin-to-skin contact or contact with towels, razors, or even doorknobs or benches can transfer MRSA to another person. Some people, termed carriers, have MRSA strains on their body but have no symptoms; however, these people can still transfer MRSA to others by direct and indirect contact (towels or clothing that carriers have used).



Who Can Get MRSA?







Some individuals are at higher risk to get MRSA than others. People who have a chronic medical condition (for example, cancer, HIV, or any immune depression), the elderly, individuals in hospitals, or those who have had recent surgery are at higher risk for MRSA infections.