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Question 1

Nosocomial infections هەوکردنی نەخۆشخانەکان
prevention & control methods

Answer 1

definition
> Nosocomial infection: An infection that occurs 48 to 72 hours after admission to the hospital or within a specified period (10-30 days) after discharge, provided that بە مەرجێک کە… at the time of admission there are no obvious signs نیشانە دیارەکان of infection and the disease has not been in its incubation period.
> Microbial infections that appear in the first 48 hours of a patient’s hospitalization are considered دادەنرێت community-acquired infections.
> Nosocomial infections can be acquired from the environment or caused by the patient’s internal flora.
> The World Health Organization (WHO) has recently replaced the HAI (Hospital Acquired Infections) with HCAI (Health Care Acquired Infections) to highlight the importance of infection control out of the hospital environment.

Question 2

Reasons for the importance of nosocomial infections

Answer 2

> Increase the length of stay of the patient in the hospital
Increases hospital costs for the patient.
Missed working days of patients
Reducing the quality use of hospital beds
Increased risk of personnel infection

Question 3

Factors contributing to nosocomial infections (susceptibility ئامادەیی and resistance)

Answer 3

In-patients are more susceptible and less resistant to infection than the healthy population. Some reasons:

> Existence of underlying disease
Use of immunosuppressive drugs, antibiotic therapy, etc.
Elimination نەهێشتنی of the body’s natural defense barriers (skin damage following injections, change in body flora following antibiotic therapy, etc.)
Increasing the number of invasive داگیرکەرەکان technical medical methods
Drug-resistant bacteria in hospitalized patients
Complex and long-term surgeries
Density of patients in the hospitals

Intensive care units یەکەکانی چاودێری چڕ , burns, oncology, organ transplants and stem cell transplants are more susceptible زیاتر ئامادەن to infection than other departments.

Question 4

where do the microbes come from?

Answer 4

> patient’s own flora
cross infection from medical personnel
cross infection from patient to patient
hospital environment ( inanimate objects):
air
water
dust
IV fluids & catheters
washbowls
bedpans
endoscopes
ventilators & respiratory equipment

Question 5

sources of infection

Answer 5

endogenous:
> patients own flora may invade patient’s tissue during some surgical operations or instrumental manipulations
> normal commensals of the skin, respiratory , GI, UG tract

exogenous:
>from another patient , staff member , environment in the hospital
> environmental sources: inanimate objects, air, water, food
> cross infection from: other patients, hospital staff(suffering from infections or asymptomatic carriers)

Question 6

Necessary conditions and factors to cause nosocomial infection

Answer 6

Three elements must be provided to transmit the infection in the hospital:
1- Source of infectious organisms: patients, personnel, sometimes visitors and objects
2- Susceptible host
3- Transmission route: common tools, airway, vector (mosquitoes and flies)

Question 7

(Reservoirs) Source of infectious organisms

Answer 7

> It is the place where the infectious agent can survive, grow and multiply and wait for it to be transmitted to the susceptible host.
Common reservoirs of infection include humans, animals, plants, soil & water.
Common reservoirs of infection in the hospital are: patients, medical personnel, equipment and environment

Question 8

Measures to reduce nosocomial infection reservoirs

Answer 8

> Patient bathing: Using soap and water to clean and remove discharge, drainage, sweat, or sediment from patients
Dressing materials: Change periodically and at the appropriate time contaminated and wet dressings
Contaminated needles: Insert syringes and cap-free needles into perforated-resistance containers (safety box).
Contaminated material: Use of impermeable bags
Cleaning surfaces: Cleaning and drying table surfaces near the patient’s bed with appropriate detergents and disinfectants
Surgical Wounds: Keep drainage tubes and drainage bags open
Drainage containers and bags: Regular replacement of drainage containers, the drainage system should be located at a lower level than the drainage site.

Question 9

microorganisms

Answer 9

> any pathogen, on occasion, can cause HAI
those that are able to survive in hospital invironment & develop resistance to antibiotics & disinfections: major cause
commensal bacteria: found in the normal flora of healthy people.
signifivant protective role by preventing colonization by pathogenic microorganisms.
some commensal bacteria may cause infection if the host is compromised.
eg. staphylococcus epidermidis ( cause of I.V. infection)
escherichia coli (cause of urinary infections).
pathogenic bacteria: they have greater virulence , and cause infections( spordic or epidemic) regardless of host status .

Question 10

Bacteria:

Answer 10

most frequent (up to 80%) of nosocomial infectious agents. About 25 to 50 percent of all nosocomial infections are Gram-negative and 10 percent are Staphylococcal infections.

Question 11

bacteria:

Answer 11

1\ gram positive bacteria
2\ gram negative bacteria

Question 12

1\ gram positive bacteria

Answer 12

> staphylococus aureus:
bacteria that colonize the skin, nose and throat of patient and hospital staff. they cause a wide variety of lung , bone , heart and bloodstream infections and are frequently resistant to antibiotics.
in hospitals commonly 40+50% of s.aureus isolates are MRSA.
staph epidermidis & group D streptococci
streptococci: streptococcus hemplyticus & streptococcus pyogenes
clostridium tetani spores: survive in dust for very long time

Question 13

2\ gram negative bacteria

Answer 13

> in recent decades , enteric gram negative bacilli -> most important group of hospital pathogens
enterobacteriaceae:
( e.coli, proteus, klepsiella, enterobacter, serratia) may colonize sites when the host defences are compromised. they may also be highly antibiotic resistant.
pseudomonas spp:
-often isolated in water and damp areas. they may colonize the digestive tract of hospitalized patients.
- ability to survive & multiply at low temp
- resistance toward antibiotics & disinfectants

Question 14

viruses:

Answer 14

> HIV and Hepatitis B & C viruses :
transmitted through blood & blood products
viral diarrhea & chickenpox can be spread in hospitals
. cytomegalovirus, herpes virus, influenza , enteroviruses & arenaviruses can cause HAI

*Viral nosocomial infections are more important in children and infants, the elderly and those with chronic diseases.*More than 90% of viral hospital infections are respiratory and digestive viruses.

Question 15

fungi:

Answer 15

candida albicans , aspergillus , mucor

Fungal infections in the hospital have increased significantly during the last decade.*These infections are often opportunistic.

Question 16

protozoa:

Answer 16

entamoeba histolytica , plasmoida , toxoplasma gondii , pneumocystis carinii

Parasites, like fungi, are opportunistic and often develop after long-term antibiotic treatment or a weakened immune system.

Question 17

Modes of transmission

Answer 17

A-Contact transmission
B- Non-contact transmission

Question 18

A-Contact transmission: The most common way of transmission is nosocomial infection.

Answer 18

*Direct contact: The possibility of transmitting the infection is higher than indirect contact, but in practice it is less important in transmitting the infection between patients. Conversely, it is very important in transmitting infection between staff and patients. Example: MRSA and influenza
*Indirect contact: The most common way of transmitting nosocomial infections, through contamination of surfaces and objects, etc. The role of hospital staff in indirect transmission and contamination of clothing, patient sheets, needles, surgical supplies, etc. is very important.
*Contact with micro droplets: Large particles (more than 5 microns) released from the respiratory mucosa that are dispersed up to a distance of 1 meter. Discharge suction, bronchoscopy, chest physiotherapy can lead to the spread of droplets. Influenza, the coronaviruses that cause COVID- 19, and SARS, Mycoplasma, Streptococcus A, and Neisseria meningitis are transmitted this way.

Question 19

B- Non-contact transmission:

Answer 19

*Airborne transmission: by inhalation of droplet nuclei (less than 5 microns). TB bacillus, rubella virus, and varicella zoster and Aspergillus fungi are spread this way.
*Transmission from inanimate carriers: includes infections transmitted through food, water and blood products
*Transmission through living vectors: Transmission of infectious agents through mosquitoes, insects, mice and other rodents is not an important route of transmission in many countries, including Iran.

Question 20

General epidemiology of nosocomial infections

Answer 20

The four most common and important types of nosocomial infections (80% of nosocomial infections) are:
Urinary tract infections
Surgical site infections
Respiratory infections
Blood infection

Other Nosocomial Infections: These include many areas prone to infection that can lead to nosocomial infections if the right context is provided, for example:
Open wounds (ulcers, burns and pressure sores): facilitate the accumulation of bacteria and cause systemic infection
Gastrointestinal inflammation: The most common nosocomial infection in children (rotavirus is a major pathogen). Clostridium difficile is the leading cause of nosocomial gastrointestinal inflammation in adults in developed countries
Inflammation of the sinuses and other internal infections, eye infections and conjunctivitis
Inflammation of the endometrium and other infections of the genitals following the birth of a baby

Question 21

common nasocomial infections
> UTI:

Answer 21

• most common HAI (%40 of nosocomia infections)
• usually associated with catheterization or instrumentation of urethra , bladder or kidneys
• e.g\ e.coli , klebsiella , proteus , serratia , pseudomonoas , candida albicans

Question 22

> pneumonia (respiratory infections):

Answer 22

• leading cause of mortality in patients suffering from HAI
• during aspiration in unconscious patients & pulmonary ventilation
  -e.g\ staph.aureus , klebsiella , enterobacter , serratia , proteus , pseudomonas , acinetobacter , legionella , e.cole

Question 23

> wound & skin sepsis:

Answer 23

• follow surgical procedure where causative agent are introduced into the tissue during operations
• higher in elderly patients
• manifest within a week of surgery
• non-surgical wounds due ti burns bed sores.
  -e.g\ staph aureus , pseudomonas aeruginosa , e.coli , proteus , enterococci

Question 24

> gastrointestinal infections:

Answer 24

• food poisoning due to salmonella, shigella sonnei
• enterotoxic manifestation due to staphylococcal contamination of cooked food
• diarhhea due to e.coli

Question 25

> bacteremia & septicemia:

Answer 25

-bacterial invasion of bloodstream in various HAIs
- mostly caused by infected intravenous cannulae
- gram negative bacilli: common pathogens

Question 26

> tetanus:

Answer 26

-inadequate attention to aseptic precautions during surgery
- use of contaminated dressing or improperly sterilized dressings
- improper disinfection of site of intramuscular injection
- inadequate care while cutting umbilical cord of new-born

Question 27

Epidemiology at the international level

Answer 27

> The frequency of the number of patients is not known precisely due to the difficulty of collecting data.
In developing countries the problem is bigger and larger (lack of surveillance system).
According to WHO estimates, the prevalence of infection due to health care in developed countries is 5.1-11.6%.
According to the CDC, 250,000 bloodstream infections occur annually following vascular catheterization in the United States, resulting in 15-25% of deaths.
The prevalence of nosocomial infections in developing countries is estimated at 5-20%. Which is 19 times higher in the use of invasive devices, more than double in the ICU and 3-20 times more common in neonatal infections comparing to developed countries.
According to the International Nosocomial Infection Control Consortium (INICC) from 30 countries in Asia, Africa, Europe and the Americas, the prevalence of drug resistance in many microorganisms is very high, with 84.1% drug-resistant Staphylococcus aureus, 76% ceftazidime-Ceftriaxone resistant Klebsiella pneumoniae and 78% piperacillin-resistant Pseudomonas aeruginosa.

Question 28

Epidemiology of nosocomial infections in Iran

Answer 28

> Establishment of nosocomial infection surveillance system in the country since 2006 (1385 solar year) and mandatory reporting of four types of nosocomial infections to relevant health centers.
In total, 57082 cases of infections have been reported to the Center for Disease Control during a 4-year period of 2007-2009, and based on this, the frequency of nosocomial infections was between 02%-5.7%.
Among the reported infections, urinary tract infections were the most common (28.9%) followed by pneumonia (28%), surgical infection (26.8%) and blood infection (16.4%).
The frequency of deaths attributed to nosocomial infections during the above period is estimated to be 14.8%.
The results of the assessment of the status of the surveillance system show that reporting in hospitals across the country is still low and the calculated frequency is far from the expected frequency of the Ministry of Health (10-15%).

Question 29

Preventive measures and control of nosocomial infections

Answer 29

Primary prevention: Aiming to prevent infection in patients and health workers. The most important measures in this regard include:
> Health education: at regular intervals for all groups including staff, patients and visitors.
> Hand hygiene: One of the simple but important ways to prevent nosocomial infections. An important universal action is setting up the: Save lives: clean Your Hands public agreement by 168 countries in 2009, according to which all medical centers are required to use alcoholic solutions for hand washing.
> Isolation of patients: with the aim of preventing the transmission of microorganisms from patients to others
> Standard precautions: In order to prevent staff and patients from contact with infectious agents of blood and body excreta, including the use of personal protective equipment (gloves, goggles, masks), necessary precautions in the use of needles and other sharp objects, respiratory hygiene (presentation By the CDC after the occurrence of SARS in 2003)
> Precautions based on the mode of transmission: In addition to standard precautions, including contact precautions (direct and indirect, such as the use of gown and gloves), droplet precautions (protective mask in contact with less than 1 meter), airborne precautions (negative pressure isolation room) and protected environment (cell transplant patients).
> Safe Injections: Measures to increase staff awareness and skills in sharp and winning tools, use of AD syringes, use of safety box
Vaccination of staff: with hepatitis B vaccine, dT, MMR and influenza
> Environmental health measures: design of operating room wards and facilities, air quality and ventilation, water supply, waste disposal, laundry, etc. by the hospital’s environmental health unit

Question 30

Preventive measures and control of nosocomial infections

Answer 30

Secondary prevention: includes two main steps:
> Early diagnosis and treatment of nosocomial infections in patients: by the nosocomial infection surveillance system
> Early detection of occupational exposure: such as needle stick, blood or discharge contact based on employee reports. At present, staff exposure to the three causes of hepatitis C, B and HIV infections is being followed up and treated.
> In these cases, the hospital infection control team is required to report the date and time of contact, type of substance and severity of contact, vaccination status and antibody titer of the exposed person and the source person at appropriate intervals and prophylactic vaccination, medication or immunoglobulin used.
> Prevention of antibiotic resistance: Rational use of antibiotics (choosing the right type of antibiotic, dose and appropriate duration of treatment) is one of the most important ways to prevent antibiotic resistance.
> Actions in a Nosocomial Infection Outbreak: An outbreak means an unexpected increase in a known nosocomial infection or a new infection in a hospital.
> Outbreaks appear to be identified by physicians, nurses, laboratories, or care systems
> The next step includes determining the type of outbreak, identifying the sources and reservoirs of the outbreak, and designing and implementing control measures by the hospital infection control team.

Question 31

Urinary tract infections(UTI)

Answer 31

Effective measures in prevention:
> Avoid urinary catheterization except in compulsory indications
> Limit the duration of drainage
> Maintain proper disinfection function during urinary catheter insertion and other invasive urological procedures such as cystoscopy, urodynamic test, cystography
> Hygienic hand washing before catheter insertion and use of sterile gloves during procedure
> Clean the perineal area with a disinfectant solution before inserting the catheter
> non-traumatic insertion of urinary catheter using a suitable lubricant
> Maintain a closed drainage system with rapid use of the urine bag after catheter placement

Question 32

Surgical wound infections (surgical site infections)

Answer 32

Factors affecting the recurrence of surgical wound infection:
> Surgical technique
> Background of endogenous wound infection during surgery (e.g., clean or infected)
> Duration of surgery
> Patient’s previous condition
> Operating room environment
> Release of organisms by the operating room team

Question 33

Nosocomial infections of the respiratory system

Answer 33

Appropriate preventive measures to reduce cases of ventilator-induced pneumonia in the intensive care unit:
> Proper disinfection and care when using pipes, respirators and humidifiers
> Regular replacement of machine pipes
> Sterile tracheal suction

Appropriate preventive measures in internal departments:
> Limited medication in case of impaired consciousness (analgesics and narcotics)
> Proper position of patients in a coma to limit the possibility of aspiration
> Avoid oral feeding in patients who do not swallow normally
> Special care for neutropenic or transplant patients

Question 34

Infections caused by intravascular instruments

Answer 34

These infections are more common in intensive care units. Key activities for all vascular catheters:
> Avoid catheterization unless there is a medical indication
> Maintain a high level of disinfection during catheter insertion and care
> Restrictions on the use of catheters, and the minimum possible time if used
> Prepare liquids disinfectiously
> Staff training for catheter placement and care