Saturday, February 25, 2006
Viral and serious bacterial infections in children
March 1, 2005
The Rochester criteria help physicians triage febrile children into high- and low-risk categories, depending on how likely they are to have a serious bacterial infection. The extent to which children with viral illness have a concomitant serious bacterial infection is not known, nor have any studies shown whether identifying a viral illness in febrile children reduces their risk of having a serious bacterial infection. Byington and colleagues examined whether children with viral illnesses are less likely to develop serious bacterial infections than children without viral illness.
This prospective study enrolled infants one to 90 days of age with temperatures of at least 38[degrees]C (100.4[degrees]F), testing them for respiratory viruses, including respiratory syncytial virus (RSV). All infants underwent a complete septic work-up. Infants were assigned Rochester classifications (high-risk or low-risk) and were subsequently classified as having serious bacterial infection based on bacterial culture results.
Viral testing was performed in 1,385 infants, 491 (35 percent) of whom had one or more viral infections. Of the 1,385 participants, 922 (67 percent) were classified as high-risk, and 456 (33 percent) were classified as low-risk; a determination could not be made in the remaining seven infants. Of the 1,385 infants, 131 (9.5 percent) had a serious bacterial infection. Of the 491 virally infected children, 21 (4.2 percent) had a serious bacterial infection compared with 110 (12.3 percent) of the 894 children who were not virally infected.
Bacterial meningitis occurred in six children without viruses and in none of the children with viral infections. When these findings were combined with the Rochester classifications, high-risk infants with viral infections were significantly less likely to have serious bacterial infections than high-risk infants without viral infections. The occurrence of serious bacterial infections was not significantly different in low-risk, virus-positive infants versus low-risk, virus-negative infants. High-risk virus-negative infants had a 13.67 greater occurrence of serious bacterial infections than low-risk, virus-positive infants.
RSV and enteroviruses were the most commonly identified viruses. The authors point out that technology to identify these viruses is readily available. Thus, viral testing could be used as an additional tool to triage febrile infants. Even high-risk infants who are virally infected are less likely to have bacteremia, urinary tract infection, or soft-tissue infection, whereas high-risk children without viral infection are 3.5 times more likely to have a serious bacterial infection.
CAROLINE WELLBERY, M.D.
Byington CL, et al. Serious bacterial infections in febrile infants 1 to 90 days old with and without viral infections. Pediatrics June 2004;113:1662-6.Article
Thursday, February 23, 2006
2,236% rise in MRSA-related deaths - UK
David Batty, health correspondent
Thursday February 23, 2006
The number of deaths linked to the superbug MRSA has risen by 2,236% in just over a decade, researchers said today.
Only 50 deaths in England and Wales were linked to MRSA (Methicillin-Resistant Staphylococcus Aureus) in 1993, compared with 1,168 in 2004, the Office for National Statistics said.
The number of MRSA-related deaths rose by more than one-fifth (22%) between 2003 and 2004, with the superbug mentioned on one out of every 500 death certificates. This does not mean MRSA was the cause of death, only that it contributed to it.
But 360 deaths were directly attributed to MRSA in 2004 - a 2,400% increase from 1993 when only 15 were caused by the superbug.
The figures come after the Department of Health admitted that hospitals in England were failing to meet the target to reduce MRSA rates by 50% by 2008. Specialist "hit squads" are to be sent into the 20 NHS trusts facing the biggest challenges in reducing infection rates.
The Patients Association said the figures were disappointing. Its chairman, Michael Summers, said: "It is clear that MRSA and hospital infections are winning the war in many of our wards."
Most of the deaths involving MRSA were in people aged over 85, and rates were higher among men than women. In men and women over 85 respectively, there were 543 and 258 deaths per million linked to MRSA in 2004, compared with 0.8 and 0.4 deaths per million in males and females under 45.
The superbug, which is resistant to conventional antibiotics, is linked to three out of every 1,000 deaths in NHS hospitals and nursing homes.
The figures also showed an almost 376% rise in the number of deaths linked to all types of Staphylococcus bacteria, including MRSA; from 432 in 1993 to 1,623 in 2004. The number of deaths directly attributed to all types of these infections increased by almost 352% from 156 in 1993 to 549 in 2004.
The ONS said the steep rise in deaths linked to Staphylococcus bacteria could be due to improved recording of superbug infections, perhaps as a result of public and political concern.
Department figures showed that in the six-month period from April to September 2005, 3,580 cases of MRSA bloodstream infections were reported in England - up from 3,525 for the same period the previous year.
The government's chief nursing officer, Christine Beasley, said: "It is important to put this into context. These figures show that out of 12 million people that go in to hospital in a year about 360 of them probably die directly of MRSA, but it is unacceptable for anyone to die unnecessarily from infections.
"Many people who have MRSA are very, very sick people prone to infection and not all infections are avoidable, but we are ensuring that the NHS has good hand hygiene and clinical procedures to prevent the ones that are."
Tuesday, February 21, 2006
Discovery Could Disarm Flesh-Eating Bacteria
HealthDayBy Robert PreidtMonday, February 20, 2006
MONDAY, Feb. 20 (HealthDay News) -- Scientists say they've discovered a secret weapon wielded by the family of Streptococci bacteria that causes strep throat, toxic shock and, in rare cases, the "flesh-eating bacteria."
These "group A" Streptococcus bacteria use a specific enzyme to escape defensive nets set up by the body's immune system, researchers at the University of California, San Diego (UCSD) report.
The discovery could lead to new treatments for serious infections, the scientists say.
"These findings suggest a novel approach to treating serious Strep infections, such as flesh-eating disease, by assisting our body's own defense system," senior author Dr. Victor Nizet, associate professor of pediatrics at UCSD and an infectious diseases physician at Children's Hospital in San Diego, said in a prepared statement.
He and his colleagues studied the interaction between Strep bacteria and neutrophils, specialized white blood cells that play an important role in protecting the body against pathogenic microbes. Previous research found that neutrophils release "nets" composed of DNA and toxic compounds. These nets entrap and kill bacteria that have invaded the body.
But this study found that Strep bacteria release an enzyme that degrades these nets. This enables the Strep bacteria to escape the net and spread throughout the body. However, disabling the gene that creates this enzyme makes Strep bacteria vulnerable again to the nets.
"Deprived of this single enzyme, the mutant Strep strain was easily killed by human neutrophils. In addition, the mutant Strep bacteria no longer produced a spreading infection when injected into the skin of experimental mice," lead author John Buchanan, research scientist in the UCSD department of pediatrics, said in a prepared statement.
The findings appear in the Feb. 21 issue of the journal Current Biology.
Monday, February 20, 2006
Legislation Would Help Hospitals Curb Deadly Bacterial Infections
ANNAPOLIS — When Michael Bennett's 88-year-old father caught the flu in the winter of 2004, Bennett took him to the hospital, just to be safe. He has regretted the decision ever since.
"He was just feeling miserable. So I said 'OK, let's do it'," said Bennett, a resident of Pikesville. "It was the worse mistake I ever made."
He said the hospital was where flesh-eating bacteria got into his father's leg, which later had to be amputated, and where his father caught an antibiotic-resistant strain of bacteria that eventually killed him five months later.
"My father was tortured for months by these infections," said Bennett. "It was only when I got the medical records that I discovered what he had."
Bennett's is one of a growing number of stories of people who go to hospitals to get well but instead are infected with antibiotic-resistant bacteria. The stories have attracted the attention of Maryland lawmakers who see hospitals as the frontlines for fighting the spread of resistant bacteria and other illnesses.
Legislators have proposed two laws they hope will help make hospitals safer. One would require hospitals to publicly disclose the numbers of people who get an infection from being in the hospital. The other would require hospitals and nursing homes to screen patients for antibiotic-resistant bacteria and implement hygiene protocols to prevent the spread of those bacteria.
According to the Centers for Disease Control, about two million people every year contract infections in hospitals and of those, 90,000 die from them. Of the bacteria that cause those infections, 70 percent are resistant to at least one of the drugs used to treat them.
"It's a major, major problem in hospitals today," said Senator Paula Hollinger, D-Baltimore County. "We're on our last antibiotic and bacteria are resistant to it."
Hollinger, a former nurse, has proposed a law that would require hospitals and nursing homes to adhere to the hand washing and hygiene guidelines of the Society for Healthcare Epidemiology of America. It would also require hospitals and nursing facilities to screen patients for antibiotic-resistant bacteria when they first check in, using a protocol laid out in the guidelines.
When people test positive for a resistant strain of bacteria, they would be separated from other patients, and special hygienic measures would be taken to keep the infection from moving to other patients and hospital workers.
The surveillance program would focus on two widespread and deadly strains of bacteria usually referred to as MRSA and VRE. A program similar to the one being proposed by Hollinger at the University of Pittsburg Medical Center was found to reduce MRSA infections in the medical center's intensive care unit by 90 percent.
MRSA is a strain of staphylococcus aureus that is resistant to a variety of powerful antibiotics, including methicillin and vancomycin. It is often found on the skin and in the noses of healthy people. But when it gets under the skin through scratches or surgical wounds it can cause boils and deep tissue infections that persist for months. Infections that get into the blood stream or the lungs can be fatal.
"MRSA is in every hospital in the United States, just lurking there," said Lisa McGiffert, senior policy analyst for Consumers Union, a New York-based consumer advocacy organization.
The other organism the program would focus on, VRE, is a bacterium typically found in the stomach that has evolved a resistance to vancomycin. Bennett said that his father's death certificate cited organ failure caused by VRE as the cause of death.
(Bennett declined to identify the Maryland hospital in which he believes his father contracted the bacteria. He says he is planning to sue the hospital.)
VRE is a hardy species that can travel from patient to patient on the hands of hospital workers, the method of transmission that experts say is the primary way disease spreads through hospitals.
Hollinger's bill would also require hospital workers to follow stringent hand-washing and hygiene guidelines. She said her nursing training emphasized hand hygiene as crucial to stemming the spread of microbes.
"The first rule was wash your hands, wash your hands, wash your hands," she said.
Failure to follow appropriate hand hygiene is the leading cause of the spread of antibiotic-resistant organisms, according to the CDC.
The principal of survival-of-the-fittest best describes how bacteria evolve resistance to antibiotics. Some bacteria are naturally resistant to antibiotics and thrive and multiply after their weaker competitors are killed.
Repeated and improper use of antibiotics is one of the major reasons for the development of resistance, according to experts. Taking antibiotics for a viral infection such as a cold or flu, for example, does nothing to fight the infection, and encourages the development of antibiotic-resistant strains of bacteria.
Sometimes patients improperly medicate themselves, taking antibiotic they were given for an earlier infection but did not finish - a behavior that also encourages antibiotic resistance. But doctors also contribute to the problem by bowing to pressure from patients and improperly prescribing antibiotics.
One study cited by the CDC found that doctors were over five times more likely to prescribe antibiotics to a child if they perceived that the child's parents expected the medication.
According to McGiffert the growing problem of antibiotic-resistance has cast some much needed light on the issue of the spread of disease in hospitals.
"This has been a problem in the health care system that has been hidden from the public," she said.
Consumers Union also supports a bill that would require Maryland hospitals to publicly disclose cases where people catch a disease while in the hospital. The information would be included on the hospital report cards that are already required by state law.
The bill's sponsor, Delegate Shane E. Pendergrass, D-Howard, said she learned from her father, a bacteriologist, that hospitals could be dangerous places.
He once told her when she was pregnant to get out of the hospital as quickly as possible after her baby was born to avoid infection.
Pendergrass said consumers need a way to find out how many people have caught diseases in a particular hospital.
"If you have a choice to go to a hospital that has infections and one that doesn't, which one would you go to?" she said. "It gives me as the consumer access to information about hospitals and a way to compare them."
Supporters of Pendergrass's bill, including the Maryland Hospital Association, believe it will encourage hospitals to adopted practices that reduce the spread of disease among health-care workers and patients.
"Hospitals look at how they compare to their peers," said Pageen Townsend, the senior vice president of the Maryland Hospital Association. "Nobody wants to be at the bottom."
Michael Bennett agrees that the public reporting measure would help people find out if their local hospital or nursing home has a problem and that it might encourage them to improve their hygiene practices. But reporting alone, he said, will not fix the problem.
In fact, he said one reason he does not disclose the name of the Maryland hospital where he says his father contracted the bacteria that killed him is that vilifying any one hospital would shift the focus away from a problem he thinks almost all U.S. hospitals need to face up to. He thinks the best way to fight the spread of disease is to implement the surveillance programs required by Senator Hollinger's bill.
"I'm not against public reporting, I just believe the effort needs to go to saving lives right off the bat," he said.
The Capital News Service Contributed to this report.
Friday, February 17, 2006
HU Researcher Develops Compounds to Control Bacteria
A method for controlling bacterial activity without antibiotics by interfering with their communication process has been developed by a young Hebrew University of Jerusalem researcher.
For his work, Adel Jabbour will be presented with a Kaye Innovation Award on June 6 during the 68th meeting of the Hebrew University Board of Governors. Jabbour, a Ph.D. student, conducted his work under the supervision of Prof. Morris Srebnik of the School of Pharmacy and Prof. Doron Steinberg of the Faculty of Dental Medicine. Also working on the project is graduate student Moshe Bronstein.
Most human and animal diseases are associated with bacteria that are assembled in “communities,” called biofilms, that attach themselves to many surfaces, such as live tissues, implants and teeth. Biofilm can also be found on artificial surfaces such as water pipes or air-conditioning ducts.
Only recently has it been discovered that the bacteria assembled in biofilms have a network of communication between them called “quorum sensing,” which controls their collective activity (or lack thereof). These sensing signals control the physiology and pathogenicity of the bacteria in the biofilms. A boron-based molecule that is produced by these bacteria, called auto inducer-2, controls the signals in this quorum sensing process.
Jabbour has succeeded in synthesizing modified chemical compounds, resembling the structure of the natural auto inducer-2, that can disrupt the signaling. By altering the molecular structure in these compounds, Jabbour was able to show that it is possible to control the quorum sensing responses in order to “deceive” the bacteria. The modified compounds distort the signaling that sets off the bacterial changes, making it possible to seriously hamper the bacterial action, or, if so desired, even enhance it (in those cases where the bacteria are beneficial).
Control over quorum sensing provides a promising avenue for future treatment of bacterial pathogenic activity without having to resort to antibiotic drugs with their accompanying disadvantages. On the other hand, enhancing quorum sensing could prove useful in agriculture, biotechnology and the food industry, where increasing bacterial activity would be beneficiary.
A U.S. patent has been filed based on the compounds developed by Jabbour, and further commercialization is being negotiated through the Hebrew University’s Yissum Research Development Company.
Jabbour, 32, lives in Upper Nazareth with his wife Banan, a pediatric resident in at Hadassah University Hospital-Ein Kerem. He is a graduate of St. Joseph High School in Nazareth and obtained his undergraduate degree in chemistry at the Hebrew University and his M.Sc. in pharmacy with honors from the HUSchool of Pharmacy. He is currently completing his Ph.D. studies at the School of Pharmacy and the Institute of Dental Sciences at the university under the supervision of Professors Srebnik and Steinberg.
Good’ Bacteria Could Save Patients from Infection by Deadlier Ones
Can it be that the stress on the use of antiseptics and antibiotics in hospitals is actually putting patients at a greater risk of suffering fatal bacterial infection?
Yes, argues Mark Spigelman, a visiting professor at the Sanford F. Kuvin Center for the Study of Infectious and Tropical Diseases at the Hebrew University of Jerusalem’s Faculty of Medicine. Prof. Spigelman points to a recent BBC report on the poor record of bacterial infections in patients (the worst in Europe) in British public hospitals, especially involving the deadly MRSA (methacillin resistant staphylococcus aureus) bacteria. Despite being around for 40 years, these bacteria are still basically found only in hospitals. The question Spigelman asks is why?
Spigelman, who is also a visiting professor at University College London, argues in an article appearing in the current online edition of the Annals of the Royal College of Surgeons of England that the stress on antibiotics and scrubbing with antiseptic soap may actually open an avenue for the more virulent forms of bacteria to attack patients. This is so because these “preventive” measures destroy beneficial bacteria, while at the same time the more “nasty” bacteria are often able to survive by adapting themselves to the pharmacological means used against them.
Since different strains of bacteria do not generally occupy the same surfaces, it would be better, argues Spigelman, to allow the harmless or “good” bacteria to live in the hospital environment, thus creating a kind of natural protection against the deadlier strains.
To test his hypothesis, Spigelman suggests experimenting with antibiotic-free hospitals in which harmless bacteria would be free to exist and there would be no environmental “incentive” for the more virulent strains to develop. Any patients needing antibiotics would be transferred to hospitals where they are in use. Doctors in the antibiotic-free hospitals would not enter and treat patients in antibiotic-using hospitals.
Along the same lines, he suggests that when doctors finish washing their hands with antiseptics, they might plunge their hands into a solutions saturated with harmless bacteria – for example “bioactive yoghurt.” The same approach, perhaps, should be applied to patients’ tissues that are to be exposed to surgery.
Admitting that his ideas may sound absurd to some, the fact is that MRSA has become widespread in hospitals – including in Israel as well as the UK -- where the most advanced antibiotics and most rigorous antiseptic measures are taken. One must ask, says Spigelman, “why more of the same does not seem to be working?” The approach he suggests is that “we ought to begin treating the cause and not the consequence of this disease.”
Thursday, February 16, 2006
Bacteria hone in on shopping carts - survey
SEOUL (Reuters) -
Shopping cart handles are the most bacteria-infested items among some commonly used objects while doorknobs on public bathrooms are not as bad as might be expected, according to a survey conducted in South Korea.
The Korea Consumer Protection Board tested six items that are commonly handled by the public and ran tests for their bacteria content.
Shopping cart handles led the way with 1,100 colony-forming units of bacteria per 1.55 sq inches followed by a mouse used on computers in Internet cafes, which had an average of 690 colony-forming units.
"The reason that shopping cart handles had so much bacteria is because the area is larger than the others and people have more space to place their hands," Kwon Young-il, an official at the consumer body, said by telephone.
Hand straps on buses were next with 380 units, followed by bathroom doorknobs at 340.
Rounding out the list were elevator buttons at 130 colony-forming units and hand straps on subways at 86.
The report released this week said washing hands with soap removes almost all of the bacteria.
Saturday, February 11, 2006
What is Bacterial Vaginosis?
Bacterial vaginosis or vaginitis is an inflammation which occurs in the vagina and includes several strains of germ that cause bacterial vaginosis yeast infections and trichomoniasis. Many women mistakenly believe that yeast infections are the most common type of vaginal infection but bacterial vaginosis is the most frequently occurring vaginal infection affecting from 10 percent to 64 percent of the female population at any given time.
Although treatment is available which quickly cures bacterial vaginosis, if left untreated bacterial vaginosis may increase a woman's risk of pelvic inflammatory disease (PID), endometritis, cervicitis, pregnancy complications, and post-operative infections among other health conditions.
Bacterial vaginosis occurs most during the reproductive years although women of all ages are susceptible to this infection that affects the vagina, urethra, bladder, and skin in the genital area.
What Causes Bacterial Vaginosis?
Primary causes of bacterial vaginosis include an overgrowth of anaerobic bacteria and the Gardnerella organism.
The healthy vagina includes a small amount of these bacteria and organisms. When the vaginal balance is disrupted by the overgrowth of these bacteria another protective bacterium -- lactobacilli is unable to adequately perform its normal function. Lactobacilli normally provides a natural disinfectant (similar to hydrogen peroxide) which helps maintain the healthy and normal balance of microorganisms in the vagina.
E. coli which is a normal inhabitant of the rectum can cause bacterial vaginitis if it is spread to the vaginal area. Other factors which may contribute include hot weather, poor health, poor hygiene, use of an intrauterine device (IUD) for birth control, and routine vaginal douching.
Risk of bacterial vaginosis increases with menopause, and in women with diabetes, as well as women whose resistance is lowered due to other conditions.
A report published in Women's Health Weekly indicates that multiple sex partners may increase a woman's risk of bacterial vaginosis although African-American women with only one partner still have a high prevalence of infection.
What are the Symptoms of Bacterial Vaginosis?
The most obvious sign of bacterial infection is an unpleasant foul, often fishy odor. Itching and/or burning sometimes accompany bacterial infections, but are not a required symptom for a diagnosis of bacterial vaginosis.
Many times women are unaware they are infected until they are diagnosed during a routine pelvic exam and Pap smear. It is important that you don't use vaginal douches during the few days preceding your visit to your gynecologist as douching can hide signs of infection and may make bacterial vaginosis infections worse.
What is the Treatment for Bacterial Vaginosis?
The good news is that treatment is relatively simple and effective once proper diagnosis is made. Treatment usually consists of three to seven nights of Cleocin 2% vaginal cream. Oral antibiotic treatment is sometimes prescribed and may be available if you request it from your physician. Although your symptoms may disappear before you finish your medication it's important that you complete your medication exactly as directed by your physician.
Tips for Vaginal Infection Prevention
Always wipe from front to back after bowel movements to prevent E. coli from the rectum from entering the vagina.
Douching is never a good idea. Douching may disrupt the fragile balance of natural organisms in the vagina which may lead to bacterial or yeast infection and may also cause the spread of infection up into the reproductive tract where it can do damage.
Keep the vaginal area clean and dry. Wash before and after sex with an antibacterial cleanser and thoroughly dry the vaginal area to prevent moisture from creating a breeding ground for bacteria.
Avoid tight clothing and always wear white cotton panties that help absorb moisture and allow air to circulate.
Avoid scented or treated toilet paper personal hygiene products perfumes spermicides and harsh soaps or detergents if the vaginal area is irritated.
Practice safe sex! Always use condoms to prevent STDs or other vaginal infections unless you are in a long-term monogamous relationship.
Diaphragms cervical caps and medication applicators should be thoroughly cleaned after each use.
Remember if you experience signs of a vaginal infection it is important that diagnosis is made by a physician -- most vaginal infections are not yeast infections! Self-treatment with over-the-counter (OTC) remedies for yeast infections will not cure a bacterial infection and may increase your risk of complications.
Monday, February 06, 2006
Clarithromycin-resistant genotypes and eradication of Helicobacter pylori
Ann Intern Med. 2006 Jan 17;144(2):140-1.
Clarithromycin-resistant genotypes and eradication of Helicobacter pylori.
De Francesco V, Margiotta M, Zullo A, Hassan C, Troiani L, Burattini O, Stella F, Di Leo A, Russo F, Marangi S, Monno R, Stoppino V, Morini S, Panella C, Ierardi E.
Ospedali Riuniti and University of Foggia, Foggia, Italy.
Three point mutations (A2143G, A2142G, and A2142C) have been involved in Helicobacter pylori clarithromycin resistance.
To compare the eradication rates among the different point mutations and the efficacy of triple therapy and a sequential regimen according to genotypic resistance.
Post hoc subgroup study from a multicenter, randomized trial.
Two hospitals in central and southern Italy between January and December 2001.
156 patients with H. pylori infection.
Real-time polymerase chain reaction for assessing clarithromycin resistance; histology, rapid urease test, and 13C-urea breath test at entry and after 4 to 6 weeks. I
7-day triple therapy (20 mg of rabeprazole, 500 mg of clarithromycin, and 1 g of amoxicillin) in 75 patients or a 10-day sequential regimen (20 mg of rabeprazole plus 1 g of amoxicillin for 5 days and 20 mg of rabeprazole, 500 mg of clarithromycin, and 500 mg of tinidazole for the remaining 5 days) in 81 patients. All drugs were given twice daily.
Helicobacter pylori infection was eradicated in 11 of 23 patients (48%) with the A2143G mutation and in 14 of 15 patients (93%) with either A2142G or A2142C strains (difference, 45 percentage points [95% CI, 15 to 65 percentage points]; P = 0.004). The sequential regimen achieved a higher cure rate than triple therapy in A2143G mutate strains (difference, 49 percentage points [CI, 8 to 72 percentage points]; P = 0.024).
The post hoc substudy design may require further confirmation. Other limitations are the accessibility to the tool and the cost of investigations (70 euros per patient).
The A2143G mutation seemed to be associated with a very low eradication rate. The sequential regimen achieved a higher cure rate than standard therapy even in patients with these strains.
Randomized Controlled Trial
[PubMed - indexed for MEDLINE]
Wednesday, February 01, 2006
Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs. But, TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal. TB disease was once the leading cause of death in the United States.
TB is spread through the air from one person to another. The bacteria are put into the air when a person with active TB disease of the lungs or throat coughs or sneezes. People nearby may breathe in these bacteria and become infected.
However, not everyone infected with TB bacteria becomes sick. People who are not sick have what is called latent TB infection. People who have latent TB infection do not feel sick, do not have any symptoms, and cannot spread TB to others. But, some people with latent TB infection go on to get TB disease.
People with active TB disease can be treated and cured if they seek medical help. Even better, people with latent TB infection can take medicine so that they will not develop active TB disease.
Starting in the 1940s, scientists discovered the first of several medicines now used to treat TB. As a result, TB slowly began to decrease in the United States. But in the 1970s and early 1980s, the country let its guard down and TB control efforts were neglected. As a result, between 1985 and 1992, the number of TB cases increased. However, with increased funding and attention to the TB problem, we have had a steady decline in the number of persons with TB since 1992. But TB is still a problem; more than 14,000 cases were reported in 2003 in the United States.
This booklet answers common questions about TB. Please ask your doctor or nurse if you have other questions about latent TB infection or TB disease.
TB is spread through the air from one person to another. The bacteria are put into the air when a person with active TB disease of the lungs or throat coughs or sneezes. People nearby may breathe in these bacteria and become infected.
When a person breathes in TB bacteria, the bacteria can settle in the lungs and begin to grow. From there, they can move through the blood to other parts of the body, such as the kidney, spine, and brain.
TB in the lungs or throat can be infectious. This means that the bacteria can be spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious.
People with active TB disease are most likely to spread it to people they spend time with every day. This includes family members, friends, and coworkers.
In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. The bacteria become inactive, but they remain alive in the body and can become active later. This is called latent TB infection. People with latent TB infection
have no symptoms
don't feel sick
can't spread TB to others
usually have a positive skin test reaction
can develop active TB disease if they do not receive treatment for latent TB infection
Many people who have latent TB infection never develop active TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have weak immune systems, the bacteria become active and cause TB disease.
TB bacteria become active if the immune system can't stop them from growing. The active bacteria begin to multiply in the body and cause active TB disease. The bacteria attack the body and destroy tissue. If this occurs in the lungs, the bacteria can actually create a hole in the lung. Some people develop active TB disease soon after becoming infected, before their immune system can fight the TB bacteria. Other people may get sick later, when their immune system becomes weak for another reason.
Babies and young children often have weak immune systems. People infected with HIV, the virus that causes AIDS, have very weak immune systems. Other people can have weak immune systems, too, especially people with any of these conditions:
cancer of the head or neck
leukemia or Hodgkin's disease
severe kidney disease
low body weight
certain medical treatments (such as corticosteroid treatment or organ transplants)
specialized treatment for rheumatoid arthritis or Crohn’s disease
Symptoms of TB depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs. TB in the lungs may cause symptoms such as
a bad cough that lasts 3 weeks or longer
pain in the chest
coughing up blood or sputum (phlegm from deep inside the lungs)
Other symptoms of active TB disease are
weakness or fatigue
sweating at night
You have spent time with a person known to have active TB disease or suspected to have active TB disease; or
You have HIV infection or another condition that puts you at high risk for active TB disease; or
You think you might have active TB disease; or
You are from a country where active TB disease is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia); or
You live somewhere in the United States that active TB disease is more common such as a homeless shelter, migrant farm camp, prison or jail, and some nursing homes); or
You inject illegal drugs.
The TB skin test
The TB skin test may be used to find out if you have TB infection. You can get a skin test at the health department or at your doctor's office. A health care worker will inject a small amount of testing fluid (called tuberculin or PPD) just under the skin on the under side of the forearm. After 2 or 3 days, you must return to have your skin test read by the health care worker. You may have a swelling where the tuberculin was injected. The health care worker will measure this swelling and tell you if your reaction to the test is positive or negative. A positive reaction usually means that you have been infected by someone with active TB disease.
If you have recently spent time with and been exposed to someone with active TB disease, your TB skin test reaction may not be positive yet. You may need a second skin test 8 to 10 weeks after the last time you spent time with the person. This is because it can take several weeks after infection for your immune system to react to the TB skin test. If your reaction to the second test is negative, you probably do not have latent TB infection.
QuantiFERON®-TB Gold (QFT) is a blood test used to find out if you are infected with TB bacteria. The QFT measures the response to TB proteins when they are mixed with a small amount of blood. Currently, few health departments offer the QFT. If your health department does offer the QFT, only one visit is required, at which time your blood is drawn for the test.
Latent TB Infections
How can I get tested for TB?
What if I have a positive test for TB?
What if I have been vaccinated with BCG?
If I have latent TB infection, how can I keep from developing active TB disease?
What if I have HIV infection?
Active TB Disease
How is active TB disease treated?
What are the side effects of medicines for TB?
Why do I need to take TB medicine regularly?
How can I remember to take my TB medicine?
What is directly observed therapy?
How can I keep from spreading TB?
What is multidrug-resistant TB?
Active TB disease – an illness in which TB bacteria are multiplying and attacking different parts of the body. The symptoms of active TB disease include weakness, weight loss, fever, no appetite, chills, and sweating at night. Other symptoms of active TB disease depend on where in the body the bacteria are growing. If active TB disease is in the lungs (pulmonary TB), the symptoms may include a bad cough, pain in the chest, and coughing up blood. A person with active TB disease may be infectious and spread TB to others.
BCG – a vaccine for TB named after the French scientists who developed it, Calmette and Guérin. BCG is not widely used in the United States, but it is often given to infants and small children in other countries where TB is common.
Chest x-ray – a picture of the inside of your chest. A chest x-ray is made by exposing a film to x-rays that pass through your chest. A doctor can look at this film to see whether TB bacteria have damaged your lungs.
Contact – a person who has spent time with a person with infectious TB.
Culture – a test to see whether there are TB bacteria in your phlegm or other body fluids. This test can take 2 to 4 weeks in most laboratories.
Directly observed therapy (DOT) – a way of helping patients take their medicine for TB. If you get DOT, you will meet with a health care worker every day or several times a week. You will meet at a place you both agree on. This can be the TB clinic, your home or work, or any other convenient location. You will take your medicine while the health care worker watches.
Extrapulmonary TB – active TB disease in any part of the body other than the lungs (for example, the kidney, spine, brain, or lymph nodes).
HIV infection – infection with the human immunodeficiency virus, the virus that causes AIDS (acquired immunodeficiency syndrome). A person with both latent TB infection and HIV infection is at very high risk for active TB disease.
INH or isoniazid – a medicine used to prevent active TB disease in people who have latent TB infection. INH is also one of the four medicines often used to treat active TB disease.
Latent TB infection – a condition in which TB bacteria are alive but inactive in the body. People with latent TB infection have no symptoms, don't feel sick, can't spread TB to others, and usually have a positive skin test reaction. But they may develop active TB disease if they do not receive treatment for latent TB infection.
Multidrug-resistant TB (MDR TB) –active TB disease caused by bacteria resistant to two or more of the most important medicines: INH and RIF.
Mycobacterium tuberculosis – bacteria that cause latent TB infection and active TB disease.
Negative – usually refers to a test result. If you have a negative TB skin test reaction, you probably do not have TB infection.
Positive – usually refers to a test result. If you have a positive TB skin test reaction, you probably have TB infection.
Pulmonary TB – active TB disease that occurs in the lungs, usually producing a cough that lasts 3 weeks or longer. Most active TB disease is pulmonary.
QuantiFERON-TB® Gold (QFT) – a blood test used to find out if you are infected with TB bacteria. The QFT measures the response to TB proteins when they are mixed with a small amount of blood.
Resistant bacteria – bacteria that can no longer be killed by a certain medicine.
Smear – a test to see whether there are TB bacteria in your phlegm. To do this test, lab workers smear the phlegm on a glass slide, stain the slide with a special stain, and look for any TB bacteria on the slide. This test usually takes 1 day to get the results.
Sputum – phlegm coughed up from deep inside the lungs. Sputum is examined for TB bacteria using a smear; part of the sputum can also be used to do a culture.
TB skin test – a test that is often used to detect latent TB infection. A liquid called tuberculin is injected under the skin on the lower part of your arm. If you have a positive reaction to this test, you probably have latent TB infection.
Tuberculin or PPD – a liquid that is injected under the skin on the lower part of your arm during a TB skin test. If you have latent TB infection, you will probably have a positive reaction to the tuberculin.
Centers for Disease Control