hospital acquired infections nosocomial

1. HOSPITAL ACQUIRED INFECTIONS

2. • Introduction
• Definition, Criteria for inclusion, Diseases included/ not included
• Epidemiology
• Source
• Site
• Mode of infection
• Microorganisms
• Reservoir & Transmission
• Recipient of infection
• Epidemiological markers
• Prevention
• Antimicrobial Resistance
• Hospital Acquired Infections Control Committee
Nosocomial Infections 2

3. HOSPITAL ACQUIRED/ NOSOCOMIAL INFECTIONS/
CROSS INFECTIONS
• Infections acquired during hospital care which are
not present or incubating at admission.
• Infections occurring more than 48 hours after
admission are usually considered nosocomial.
Nosocomial Infections 3

4. • Should encompass infections occurring in patients
receiving treatment in any health care setting.
• Infections acquired by staff or visitors to the hospital
or other health care setting.
4Nosocomial Infections

5. Criteria to be classified as Nosocomial Infections
– Not present at time of admission
– Not related to primary disease at time of
hospitalization
– New disorder developed in the patient following
hospitalization
Nosocomial Infections 5

6. Special situations
considered as
Nosocomial infections
1.Infection acquired in
hospital becoming
apparent after
discharge
2.Infection of neonate
from passage thru birth
canal
Special situations NOT
considered as
Nosocomial infections
1. Infections associated
with complication
2. Extension of infection
already present
3. Trans-placental
infection of neonate
Nosocomial Infections 6

7. • Important case of Mortality & Morbidity worldwide
• Prevalence survey - 8.7% of hospital patients. Higher
prevalence in EMRO and SEARO
– Study by WHO in 14 countries representing 4 WHO
Regions
• 25-40% in India
• 1.4 million people affected worldwide.
7Nosocomial Infections

8. Impact of Nosocomial infections
• May lead to disabling conditions - reduce QoL
• Leading causes of death.
• Economic costs –
– increased length of stay- overall increase- 8.2 days
(3 days for gynaec, 9.9- gen surg and 19.8- ortho)
– Indirect costs due to lost work.
– Increased use of drugs, need for isolation, and use
of additional diagnostic studies also contribute.
• Divert scarce funds to the management of potentially
preventable conditions.
Nosocomial Infections 8

9. • Impact of Nosocomial infections
– Mortality - ↑ 7 fold
– Patient cost - ↑ 3 fold
– Length of hospital stay - ↑ 11 days
Nosocomial Infections 9

10. Factors influencing development of HAI
1. Microbial agent
– Characteristics, including resistance to
antimicrobial agents, intrinsic virulence, and
amount (inoculum) of infective material.
2. Patient Susceptibility
– age, immune status, underlying disease, and
diagnostic and therapeutic interventions.
Nosocomial Infections 10

11. 3. Environmental factors
– Patients with infections or carriers – potential
sources of infection.
– Crowding, frequent transfers of patients, and
concentration of highly susceptible patients in
one area
4. Bacterial Resistance
Nosocomial Infections 11

12. Predetermining factors
• Patient factors
– Debility, Old age, trauma, Risky behaviour,
immuno-suppressive conditions, impaired gag
reflex
• Interventions
– Surgical incision, urinary catheters, IV devices,
anaesthetic ventilator
• Hospital Environment
– Overcrowding, lack of hygiene, cross infetions
Nosocomial Infections 12

13. Sources of Infection
• Exogenous
– Other patients, hospital staff, inanimate objects
• Endogenous
– Patients own flora which at the time of infection
• May invade patients tissues spontaneously
• May be introduced iatrogenically
–Surgical procedure
–Nursing care
–Instrumental manipulation
Nosocomial Infections 13

14. Infection Sites
14Nosocomial Infections

15. Type of
nosocomial
Infection
Simplified criteria
Surgical site
infection
Any purulent discharge, abscess, or spreading
cellulitis at the surgical site during the month
after operation
Urinary infection Positive urine culture (1 or 2 species) with at least
105 bacteria/ml, with or without clinical
symptoms
Respiratory
infection
Respiratory symp. with at least two signs:
— cough
— purulent sputum
— new infiltrate on CXR consistent with Infection
Vascular
catheter
Inflammation, lymphangitis or infection purulent
discharge at the insertion site of the catheter
Septicaemia Fever or rigours & at least one +ve blood culture15Nosocomial Infections

16. 1. URINARY INFECTIONS
– Most common nosocomial infection
– 80% associated with indwelling bladder catheter
– Less morbidity than other nosocomial infections,
occasionally lead to bacteraemia and death.
– Bacteria responsible
• Escherichia coli
• Multi-resistant Klebsiella
Nosocomial Infections 16

17. 2. SURGICAL SITE INFECTIONS
• Incidence varies from 0.5 to 15%
• Considerable impact on hospital costs and
postoperative length of stay (3 and 20 addnl days)
• Infection is usually acquired during the operation:
– exogenously – from air, medical equipment,
surgeons and other staff),
– endogenously – from flora on the skin or in the
operative site or,
– rarely, from blood used in surgery.
Nosocomial Infections 17

18. • Infecting microorganisms – variable
• Risk factors
– Extent of contamination during the procedure (clean,
clean-contaminated, contaminated, dirty)
– patient’s general condition .
– quality of surgical technique,
– foreign bodies including drains,
– virulence of the microorganisms,
– concomitant infection at other sites,
– preoperative shaving,
– experience of the surgical team.
Nosocomial Infections 18

19. 3. NOSOCOMIAL PNEUMONIA
• Patients on ventilators in ICUs – rate of pneumonia is
3% per day.
• Microorganisms :
– Often endogenous (digestive system or nose and
throat),
– May be exogenous, often from contaminated
respiratory equipment.
Nosocomial Infections 19

20. • Patients with seizures or decreased level of
consciousness are at risk for nosocomial infection,
even if not intubated.
– Children – Viral bronchiolitis (RSV)
– Elderly – Influenza and secondary bacterial
pneumonia.
– Immuno-compromised – Legionella, Aspergillus
– High prevalence of TB, particularly MDR.
Nosocomial Infections 20

21. 4. NOSOCOMIAL BACTERAEMIA
• Approx. 5% of nosocomial inf.; high CFR (>50%).
• Incidence is increasing- multiresistant coagulase-
negative Staphylococcus and Candida spp.
• Infection may occur at
– skin entry site of the intravascular device, or
– in the sc path of the catheter (tunnel infection).
– Resident/ transient cutaneous flora is the source
• Main risk factors
– length of catheterization,
– level of asepsis at insertion, and
– continuing catheter care.
Nosocomial Infections 21

22. 5. OTHER NOSOCOMIAL INFECTIONS
• Skin and soft tissue infections: open sores (ulcers,
burns and bedsores).
• Gastroenteritis
– most common nosocomial infection in children
– Rotavirus in children, Clostridium difficile in adults
• Sinusitis and other enteric infections, infections of
the eye and conjunctiva.
• Endometritis and other infections of the
reproductive organs following childbirth.
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23. MICROORGANISMS
• BACTERIA
– Staph. aureus, Strep. pyogenes, Strep. Pneumoniae,
– Cl. Tetani, Enterococci, E. coli, Klebsiella, Pseudomonas
• VIRUS
– Hep B, C, D, HIV, Herpes, CMV
• Parasites
– Toxoplasma gond, E. histolytica
– Pneumocystis carinii, Cryptosporidium
• Fungi
– Aspergilus, Candida
Nosocomial Infections 23

24. MICROORGANISMS
• BACTERIA
– Most common nosocomial pathogens.
– Commensal bacteria
• Cutaneous coagulase negative staphylococci –
IV line infection
• Intestinal E. coli – most common cause of
urinary infection.
– Pathogenic Bacteria
24Nosocomial Infections

25. – Pathogenic bacteria
• Greater virulence; cause infections (sporadic or
epidemic) regardless of host status.
• Anaerobic Gram-positive rods (Clostridium)
cause gangrene.
• Gram-positive cocci:
– Staph aureus – lung, bone, heart and bloodstream
infections; frequently resistant to antibiotics;
– Beta-haemolytic streptococci.
Nosocomial Infections 25

26. • Enterobacteriacae (E. coli, Proteus, Klebsiella,
Enterobacter, Serratia marcescens),
– Colonize sites during catheter insertion, bladder
catheter, cannula insertion
– May be highly resistant.
• Pseudomonas sp. – in water and damp areas. May
colonize digestive tract of hospitalized patients.
• Legionella sp. – pneumonia through inhalation of
aerosols containing contaminated water (AC,
showers, therapeutic aerosols).
Nosocomial Infections 26

27. VIRUS
• Hepatitis B and C viruses
– (transfusions, dialysis, injections, endoscopy),
• RSV, Rotavirus, and Enteroviruses
– (hand-to-mouth contact and via faecal-oral route).
• Other viruses – CMV, HIV, Ebola, Influenza viruses,
HSV, Varicella-zoster virus.
Nosocomial Infections 27

28. PARASITES AND FUNGI
• Giardia lamblia – among adults or children.
• Opportunistic infections during extended antibiotic
treatment and severe immuno-suppression
– Candida albicans, Aspergillus spp., Cryptococcus
neoformans, Cryptosporidium.
• Environmental contamination – Aspergillus spp.
originate in dust and soil.
• Sarcoptes scabies (scabies) – repeated outbreaks in
health care facilities.
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29. RESERVOIRS & TRANSMISSION
1. Permanent or transient flora of the patient
(endogenous infection)
– Transmission to sites outside natural habitat (urinary
tract),
– damage to tissue (wound) or
– inappropriate antibiotic therapy that allows overgrowth (C.
difficile, yeast spp.)
• Gm -ve bacteria in GIT cause surgical site
infections after abdominal surgery or UTI in
catheterized patients.
29Nosocomial Infections

30. 2. Flora from another patient or member of
staff (exogenous cross-infection)
• through direct contact between patients (hands,
saliva droplets or other body fluids),
• in the air (droplets or dust contaminated by a
patient’s bacteria),
• via staff contaminated through patient care (hands,
clothes, nose and throat) who become transient or
permanent carriers,
• via objects contaminated by the patient (including
equipment), staff’s hands, visitors or other
environmental sources (e.g. water, other fluids,
food). Nosocomial Infections 30

31. 3. Flora from the health care environment (endemic
or epidemic exogenous environmental infections).
• in water, damp areas, and occasionally in sterile
products or disinfectants (Pseudomonas,
Acinetobacter, Mycobacterium)
• in linen, equipment & supplies used in care
• in food
• in fine dust and droplet nuclei generated by coughing
or speaking
– (bacteria smaller than 10 μm in diameter remain
in the air for several hours and can be inhaled in
the same way as fine dust).
Nosocomial Infections 31

32. RECIPIENT OF INFECTION
• Susceptible Patients
– Extremes of age — infancy and old age
– Chronic disease such as malignancy, DM, renal
failure, or AIDS
– Immunosuppressive drugs or irradiation
– Injuries to skin or mucous membranes bypass
natural defence mechanisms.
– Malnutrition
Nosocomial Infections 32

33. Wards of Hospital with higher prevalence of
Nosocomial infections
– Burns unit
– ICU & CCU
– Neonatology ward and NICU
– PNC ward
– Post Operative Surgical ward
– Oncology ward
– Haematology ward
– Stroke ward and PMR units (esp. UTI)
Nosocomial Infections 33

34. Modes of Infection
– Oral
– Airborne
– Injection
– Contact with equipment
Nosocomial Infections 34

35. Epidemiological markers for Nosocomial
Infections
• Definition :
– a test which establishes similarity or differences of
the organism
• Importance:
– To find source of infection
Nosocomial Infections 35

36. 1. Antibiogram/ Resistogram –
– S aureus, Salmonella, Pseudomonas, Proteus
2. Bio-typing
– H influenza, S aureus, Klebsiella, Proteus, E coli
3. Phage typing
– S aureus, Salmonella, Klebsiella, Pseudomonas
4. Sero-typing
– Campylobacter, Shigella, Ecoli, Pseudomonas
5. Serum Opacity Factor - Streptococci
6. Protein Markers - S aureus, H influenzae
7. RNA Electrophoresis - Rotavirus
8. Cytotoxicity Assay
9. Reverse phage typing - S aureus
10. Plasmid Profile - multiple organisms
Nosocomial Infections 36

37. Prevention of Nosocomial Infections
1. Risk Stratification
2. Reducing Person-to-person transmission
3. Preventing transmission from the environment
37Nosocomial Infections

38. Risk Stratification
38Nosocomial Infections

39. Reducing person-to-person transmission
1. Hand decontamination
– Minimal and Moderate Risk
• Hand-washing with non-antiseptic soap or rubbing with alcoholic
solution
– Surgical scrub (surgical care):
• surgical hand and forearm washing with antiseptic soap and
sufficient time and duration of contact (3–5 min).
2. Personal hygiene
– All staff must maintain good personal hygiene.
• Nails clean and kept short.
• Hair must be worn short or pinned up.
• Beard and moustaches must be kept trimmed short and clean.
Nosocomial Infections 39

40. 3. Clothing
– Working clothes
• Normally, clothes covered by a white coat.
• In special areas (burn or ICUs) : OT gown
– Shoes
• In aseptic units and in operating rooms, dedicated shoes.
– Caps
• In aseptic units, operating rooms, or performing selected invasive
procedures.
– Masks
• Cotton wool, gauze, or paper are ineffective.
• Paper masks with synthetic material for filtration effective barrier
against microorganisms.
– Gloves
• sterile gloves for surgery, care for immuno-compromised patients,
invasive procedures which enter body cavities.
40Nosocomial Infections

41. 4. Safe injection practices
– To prevent transmission of infections between patients
with injections:
• eliminate unnecessary injections
• use sterile needle and syringe
• use disposable needle and syringes, if possible
• prevent contamination of medications
• follow safe sharps disposal practices
41Nosocomial Infections

42. 5. Nursing practices
– Barrier Nursing
– Task Nursing
– Appropriate rotation on Duty
42Nosocomial Infections

43. Preventing transmission from the environment
– 90% of microorganisms present within “visible dirt”.
– Neither soap nor detergents have antimicrobial activity;
cleaning process depends essentially on mechanical action.
1. Cleaning of the hospital environment
2. Use of Hot/Superheated water
3. Disinfection of patient equipment
4. Sterilization
5. Structural Measures
43Nosocomial Infections

44. 1. Cleaning of the hospital environment
• Zone A:
– no patient contact.
– Normal domestic cleaning (e.g. administration, library).
• Zone B:
– care of patients who are not infected, and not highly susceptible,
– No Dry sweeping or vacuum cleaners are not recommended. Use
detergent solution.
• Zone C:
– infected patients (isolation wards).
– Clean with detergent/disinfectant solution, separate cleaning equipment.
• Zone D:
– highly-susceptible patients (protective isolation) or protected areas such
as OT, delivery rooms, ICUs, haemodialysis units.
– Clean with detergent/ disinfectant solution, separate cleaning equipment.
44Nosocomial Infections

45. 2. Use of hot/superheated water
45Nosocomial Infections

46. 3. Disinfection of patient equipment
Disinfection removes microorganisms without complete
sterilization to prevent transmission of organisms between
patients.
• Procedures must :
– meet criteria for killing of
organisms
– have a detergent effect
– act independently of
bacterial concentration,
hardness of water, or
presence of soap and
proteins (that inhibit some
disinfectants).
• To be acceptable:
– easy to use
– non-volatile
– not harmful to equipment,
staff or patients
– free from unpleasant
smells
– effective within a relatively
short time.
46Nosocomial Infections

47. Levels of Disinfection
– High-level disinfection (critical)
• destroy all microorganisms, except heavy contamination by
bacterial spores.
– Intermediate disinfection (semi-critical)
• inactivates M. tuberculosis, vegetative bacteria, most viruses and
fungi, but not necessarily kill bacterial spores.
– Low-level disinfection (non-critical)
• kill most bacteria, some viruses and some fungi, but cannot be
relied on for killing more resistant bacteria such as M. tuberculosis
or bacterial spores.
47Nosocomial Infections

48. 4. Sterilization
– Destruction of all microorganisms.
– Operationally defined as a decrease in microbial load by
10-6.
– Thermal sterilization
• Wet sterilization:
– water at 121°C for 30 min, or 134°C for 13 min in autoclave.
• Dry sterilization:
– exposure to 160°C for 120 min, or 170°C for 60 min; less reliable than
the wet process.
– Chemical sterilization
• Ethylene oxide, formaldehyde – (phased out)
• Peracetic acid instead.
48Nosocomial Infections

49. 5. Structural Measures
I. Building
• traffic flow to minimize exposure of high-risk patients and
facilitate patient transport
• adequate spatial separation of patients
• adequate number and type of isolation rooms
• appropriate access to handwashing facilities
• materials (e.g. carpets, floors) that can be adequately cleaned
• appropriate ventilation for isolation rooms and special patient
care areas (operating theatres, transplant units)
• preventing patient exposure to fungal spores with renovations
Nosocomial Infections 49

50. II. Air Flow
– Outdoor air inlets located high above ground level; away from
ventilation discharge outlets, incinerators, or boiler stacks.
– Within rooms, ceiling inlets and low wall outlets allow clean air to
move downward through the area toward the contaminated floor.
– Cooling towers and humidifiers should be regularly inspected and
cleaned – Legionella spp.
– Positive air pressure for areas which must be as clean as possible.
– Zoning of air systems may confine the air of a department to that
department alone.
Nosocomial Infections 50

51. – Microbiology laboratories : use special unidirectional airflow hoods to
handle microbial cultures.
– Pharmacies : Hoods to prevent airborne contamination of sterile fluids
when containers are opened – when adding antibiotic to sterile IVF.
– ICUs : laminar flow units used in the treatment of immunosuppressed
patients.
– Operating theatres : unidirectional clean airflow system with a
minimum an air speed of at least 0.25 m/s, ensures instrument
sterility throughout the procedure.
Nosocomial Infections 51

52. III. Waste
• Includes all waste generated by health care establishments,
research facilities, and laboratories.
• 10–25% hazardous, and may create some health risks
– Guidelines
 Segregation at source.
 General health care waste in stream of domestic refuse.
 Sharps to be collected at source in puncture-proof containers
with fitted covers → chemical treatment / shredding
 Microbiological laboratory waste sterilized by autoclaving → red
bags → autoclaving.
 Anatomical and contaminated combustible wastes → yellow bag
→ incineration
 Liquid wastes to be disinfected and discharged into drains
Nosocomial Infections 52

53. Preventive Measures
1. Hygiene : hand washing, water & food sanitation
2. Disinfection : clothes, bedsheets
3. Disposal of hospital waste
4. Good infrastructure – ventialtion, temperature
5. Judicious use of IV Fluids, antibiotics
6. Intellectual use of instrumentation
7. Chemoprophylaxis in specific situations
8. Isolation of immuno-suppressed/compromised
9. Screening and vaccination of staff
10. Infection control committee
Nosocomial Infections 53

54. Surveillance
• Collection of data
– Date of admission, duration of infection,
length of stay, Culture & sensitivity
• Analysis of data
– Incidence = Prevalence x LA
LN – INTN
LA = Mean length of hospital stay for all patients
LN = Mean length of hospital stay for patients with
nosocomial infections
INTN = Mean interval from admission to first nosocomial
infetion
Nosocomial Infections 54

55. Infection Control Precautions
55Nosocomial Infections

56. • Standard precautions for all patients
– Wash hands promptly after contact with infective material
– Use no touch technique wherever possible
– Wear gloves when in contact with blood, body fluids, secretions,
excretions, mucous membranes and contaminated items
– Wash hands immediately after removing gloves
– All sharps should be handled with extreme care
– Clean up spills of infective material promptly
– Ensure that patient-care equipment, supplies and linen
contaminated with infective material is either discarded, or
disinfected or sterilized between each patient use
– Ensure appropriate waste handling
– If no washing machine is available for linen soiled with infective
material, the linen can be boiled.
56Nosocomial Infections

57. • Additional precautions for specific modes of transmission
– Airborne precautions (droplet nuclei <5 μm)
(Tb, V-Z, measles)
• individual room with adequate ventilation – negative pressure;
door closed; at least six air exchanges/hour
• staff wearing high-efficiency masks in room
• patient to stay in room.
– Droplet precautions (droplet nuclei >5 μm)
(bacterial meningitis, diphtheria, RSV)
• individual room for the patient, if available
• mask for health care workers
• restricted circulation for the patient; patient wears a surgical mask if
leaving the room.
57Nosocomial Infections

58. – Contact precautions
• individual room for the patient if available;
• staff wear gloves on entering the room; a gown for patient contact
or contact with contaminated surfaces or material
• wash hands before and after contact with the patient, and on
leaving the room
• restrict patient movement outside the room
• appropriate environmental and equipment cleaning, disinfection,
and sterilization.
58Nosocomial Infections

59. Antimicrobial Resistance
• Discovery of sulfonamides and penicillin in the mid-20th
century → 1950 and 1970, “golden age” of antimicrobial
discovery
↓
• overuse and misuse
↓
• many microorganisms have become resistant to different
(sometimes nearly all) antimicrobial agents.
↓
• Resistant bacteria may cause increased morbidity and death,
particularly immunocompromised.
59Nosocomial Infections

60. • Continuous use of antimicrobial agents → selection pressure
→ emergence, multiplication, and spread of resistant strains.
• Inappropriate and uncontrolled use
– overprescribing, administration of suboptimal doses,
insufficient duration of treatment, misdiagnosis,
underdosing due to shortage of antibiotics.
• Nosocomial infections are often caused by antibiotic- resistant
organisms
60Nosocomial Infections

61. Alexander Fleming
“Penicillin” Nobel Lecture, 1945
"The time may come
when penicillin can be
bought by anyone in
the shops. Then there
is the danger that the
ignorant man may
easily underdose
himself and by
exposing his microbes
to non‐lethal
quantities of the drug
make them resistant.”
61Nosocomial Infections