The Most Common Bacteria in Healthcare Associated Infections
Bacteria are the most common cause of healthcare-associated infections (HAIs). According to the CDC, the following bacteria are some of the most common organisms in healthcare settings.
1. Acinetobacter
Who’s at risk: extremely ill people; those with weakened immune systems, chronic lung disease, diabetes; hospitalized patients, especially those on a ventilator; patients with a prolonged hospital stay; those who have open wounds; any person with invasive devices (urinary catheters, feeding tubes, ventilators, IV catheters)
Transmission: person-to-person contact, contact with contaminated surfaces, wounds contaminated with dirt or debris
Symptoms: depend on body part that is affected – pneumonia symptoms include fever, chills or cough; wound infection symptoms include redness, increasing pain, pus discharging from the wound
Can cause: blood or lung infections, pneumonia, meningitis, urinary tract infections, skin or wound infections
2. Burkholderia cepacia
Who’s at risk: people with weakened immune systems or chronic lung diseases (such as cystic fibrosis)
Transmission: contaminated medications and medical devices, person-to-person contact, contact with contaminated surfaces, exposure to B. cepacia in the environment
Symptoms: rages from no symptoms to serious respiratory infections
Can cause: pneumonia
3. Clostridium difficile
Who’s at risk: older adults in hospitals or in long-term care facilities
Transmission: fecal-oral route; most commonly being transferred from an infection site to another patient by a healthcare provider’s hands
Symptoms: watery diarrhea three or more times a day for two or more days, fever, abdominal pain, tenderness
Can cause: life-threatening inflammation of the colon
4. Clostridium sordellii
Who’s at risk: patients with underlying medical conditions; women following the end of pregnancy
Transmission: unknown; similar species are spread from person-to-person and sometimes contaminated surfaces
Symptoms: nausea, vomiting, diarrhea, occasional abdominal pain without fever
Can cause: pneumonia, endocarditis, peritonitis, myonecrosis; severe cases lead to sepsis
5. Enterobacteriaceae (carbapenem-resistance)
Who’s at risk: patients receiving treatment for other conditions; patients whose care requires invasive medical devices; patients taking long courses of certain antibiotics
Transmission: person-to-person contact; contact with an infected device (such as a catheter or ventilator)
Symptoms: high fever, sepsis, septic shock, severe urinary tract infection
Can cause: bloodstream infections, wound infections, urinary tract infections, meningitis, pneumonia
6. Hepatitis A
Who it affects: people who share illegal drugs (injected or not); those with clotting-factor disorders (such as hemophilia); men who have sexual contact with other men; those who have oral-anal sexual contact with someone who has Hepatitis A
Transmission: person-to-person contact, contact with objects, food or drinks contaminated by the feces (or stool) of an infected person
Symptoms: fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, clay-colored bowel movements, jaundice
Can cause: acute liver failure
7. Hepatitis B
Who it affects: those who have unprotected sex with multiple sex partners or someone infected; those who share needles during IV drug use; men who have sex with other men
Transmission: spreads through contact with blood, semen or other bodily fluids from an infected person
Symptoms: not common; mild to severe symptoms if experienced include abdominal pain, dark urine, fever, joint pain, nausea and vomiting, weakness and fatigue (similar to Hepatitis A)
Can cause: acute infections leading to cirrhosis, liver cancer, liver failure
8. Hepatitis C (HCV)
Who’s at risk: current or former injection drug users; recipients of blood transfusions or solid organ transplants before July 1992 (when better testing of blood donors became available); those with HIV infection; chronic hemodialysis patients; children born to HCV-positive mothers
Transmission: contaminated syringes, needles or sharps; infected blood transfusions; organ transplants that have not undergone proper HCV screening
Symptoms: not common; mild to severe symptoms are similar to those for Hepatitis A and B
Can cause: chronic liver disease, cirrhosis, liver cancer, death
9. Human Immunodeficiency Virus (HIV /AIDS)
Who’s at risk: those who have unprotected sex; those with another STI; those who use IV drugs
Transmission: improper infection control procedures such as sterilization and disinfection; exchange of bodily fluids
Symptoms: fever, headache, muscle aches and joint pain, rash, sore throat, swollen lymph glands, mainly on the neck
Can cause: tuberculosis, cytomegalovirus (herpes virus), candidiasis (HIV-related infection), cryptococcal meningitis
10. Influenza
Who’s at risk: people over age 65; people with certain chronic medical conditions (such as asthma, diabetes or heart disease); pregnant women; young children
Transmission: spread mainly by droplets made when people with influenza cough, sneeze or talk
Symptoms: cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue
Can cause: pneumonia, bronchitis, sinus and ear infections
11. Klebsiella pneumoniae
Who’s at risk: premature infants and infants in the neonatal intensive care unit; patients with ventilators, intravenous catheters; patients taking long courses of certain antibiotics; patients requiring invasive medical devices, urinary catheters, ventilators
Transmission: person-to-person contact or contamination of medical devices
Symptoms: sharp head pain, nausea, dizziness, impaired memory
Can cause: pneumonia, bloodstream infections, wound or surgical site infections, meningitis, urinary tract infections, upper respiratory tract infections, osteomyelitis
12. Methicillin-resistant Staphylococcus aureus (MRSA)
Who’s at risk: people who have been in hospitals or other health-care settings, such as nursing homes and dialysis centers
Transmission: direct contact usually through an open wound or contaminated hands
Symptoms: small, red bump, pimple or boil can appear on skin; area may be tender, swollen, warm or filled with pus
Can cause: life-threatening bloodstream infections, pneumonia, surgical site infections
13. Mycobacterium abscessus
Who’s at risk: people with open wounds or those who receive injections without appropriate skin disinfection
Transmission: infected equipment or material in invasive medical procedures, or when contaminated substances are injected into a patient
Symptoms: infected skin is usually red, warm, tender, swollen and / or painful; infected areas can also develop boils or pus-filled vesicles; other signs include fever, chills, muscle aches
Can cause: infections of the skin (or soft tissue under the skin), lungs
14. Mycobacterium tuberculosis
Who’s at risk: people with medical conditions that weaken the immune system; people in facilities where TB disease is very common
Transmission: airborne; close contact with people who have infectious tuberculosis; bacteria are put into the air when a person with a TB disease of the lungs or throat coughs, sneezes, speaks or sings
Symptoms: a bad cough lasting 3 weeks or longer, pain in the chest, coughing up blood or sputum (mucus from deep inside the lungs)
Can cause: tuberculosis
15. Norovirus
Who’s at risk: the elderly, young children, people with other medical illnesses
Transmission: person-to-person contact
Symptoms: diarrhea, vomiting, nausea, stomach pain, fever, headache, body aches, symptoms of dehydration
Can cause: acute gastroenteritis
16. Pseudomonas aeruginosa
Who’s at risk: those with weakened immune systems, patients with catheters or ventilators, patients with wounds from surgery or burns; those with a prolonged hospital stay
Transmission: person-to-person contact, contamination of medical equipment
Symptoms: depend on infection location – blood: fever, chills, fatigue, muscle pains; lungs: chills, fever, difficulty breathing; skin: itchy rash, bleeding ulcers; ear: swelling, ear pain, itching inside ear
Can cause: pneumonia, sepsis, burn wound infections, meningitis
17. Staphylococcus aureus (Staph)
Who’s at risk: people with underlying health conditions (such as HIV/AIDS, cancer, respiratory illness), patients who are currently or have recently been hospitalized, patients using invasive devices (urinary catheters, feeding tubes, IV catheters)
Transmission: improper hygiene
Symptoms: collection of pus, such as a boil or abscess; area is typically tender or painful and may be reddened and swollen
Can cause: pneumonia, endocarditis, osteomyelitis
18. Stenotrophomonas maltophilia
Who’s at risk: patients requiring catheters, breathing tubes, and IV fluids
Transmission: use of hospital appliances such as catheters, IV lines and breathing tubes in immunocompromised people
Symptoms: vary depending on infection- urinary tract: burning during urination, cloudy or bloody urine; blood infection: increased heart rate, fever, increased respiratory rate
Can cause: pneumonia, urinary tract infections, sepsis, pulmonary infections
19. Vancomycin-intermediate Staphylococcus aureus (VISA) and Vancomycin-resistant Staphylococcus aureus (VRSA)
Who’s at risk: those with underlying health conditions (such as diabetes, kidney disease); patients with devices going into their bodies (such as catheters), patients with previous infections with methicillin-resistant Staphylococcus aureus, and those with recent exposure to vancomycin and other antimicrobial agents
Transmission: person-to-person, touching contaminated surfaces or materials
Symptoms: skin infections, abscesses
Can cause: pneumonia, endocarditis, osteomyelitis, sepsis, infection of the heart valve
20. Vancomycin-resistant Enterococci (VRE)
Who’s at risk: people who are hospitalized; people with weakened immune systems; people who have undergone surgical procedures such as chest or abdominal surgery; people who have been previously treated with antibiotic vancomycin or another antibiotic for an extended period of time
Transmission: person-to-person contact, touching contaminated surfaces
Symptoms: depend on infection location- wound infection: skin may be red or tender; urinary tract infection: back pain, burning sensation when urinating; diarrhea, fatigue, fever and chills
Can cause: infections of the urinary tract, bloodstream, or of wounds associated with catheters or surgical procedures
Learn how to reduce your risk of a Healthcare Associated Infection.