Nosocomial infection and its surveillance

A patient with pneumonia visited a health care centre for
treatment and was admitted to the hospital. After 10
days of admission, this patient developed UTI. In this
case, all of the following could be the most probable
source of infection except:
a) Patient visitors
b) Hospital staffs
c) Hospital devices used in the process of treatment
d) His home place
Shyam Kumar Mishra

Nosocomial infection
Shyam Kumar Mishra
Assistant Professor,
Institute of Medicine
Shyam Kumar Mishra

Etymology
- In Greek, nosocomialis = hospital
Nosokomos (nosos = disease, komeo = to take care of)
• Related to hospital, so it is also termed as ‘Hospital
Acquired Infection (HAI)’
• Now, new term ‘’Health-care associated infection’’
Shyam Kumar Mishra

Nosocomial infection
Any clinically recognizable microbiologic disease that affects the
patients as a consequences of his being admitted to the hospital or
attending for treatment or acquired from hospital staff as a
consequence of their works whether or not the symptoms of disease
appear while the affected person is in the hospital (WHO).
A localized or systemic condition that results from adverse reaction
to the presence of an infectious agent(s) or its toxin(s) and that was
not present or incubating at the time of admission to the hospital.
(Center for Disease Control)
Shyam Kumar Mishra

• Those infections which are a result of treatment in a
hospital or hospital like setting but secondary to the
patients' original condition. Infections are considered
nosocomial if they first appear 48 hours or more after
hospital admission or within 30 days after discharge.
• For most bacterial nosocomial infections usually become
evident after 48 hours (i.e., the typical incubation period)
or more after admission. However, because the
incubation period varies with the type of pathogen and to
some extent with the patient's underlying condition, each
infection must be assessed individually for evidence that
links it to the hospitalization.Shyam Kumar Mishra

History
Dr. Ignaz Semmelweis
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Florence Nightingale
• At 1863 established the
importance principle of nursing,
hospital design and hygiene.
• Quoted remark in her book Notes
on Hospitals.
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Joseph Lister
Father of antiseptic surgery
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Even today,HAI has been the problem both in developed and
developing world. Its' explanation could be any one or more of the
following:
• Hospitals receive large numbers of sick people and whose immune
systems are often in a weakened state.
• Medical staff move from patient to patient without washing their
hands in-between, providing a way for pathogens to spread.
• Many medical procedures bypass the body’s natural protective
barriers.
• Unnecessary use of antimicrobial agents in hospitals creates
selection pressure for the emergence of resistant strains
• Other factors like hospitals age, infrastructure repairs and
renovations will create risks of airborne diseases caused by dust
and spores released during demolition and construction.
Shyam Kumar Mishra

Hospital
persons Hospital
person
Surgical
Procedures
Air
Food
Medication
Devices,
Drains,
Catheters
Water
Fomites
Insects
Patients’
normal flora
Visitors
Other patients
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Chain of infection
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Nosocomial infectionNosocomial infectionShyam Kumar Mishra

SOURCES OF HOSPITAL
INFECTIONS
A. Exogenous
- Other patients or personsor persons
(cross-infection)(cross-infection)
- Health care workers
- Hospital environment
. -. - Inanimate objectsInanimate objects
(fomites) vehicle(fomites) vehicle
Inanimate environment of the
hospital that acts as an important
source comprises
(a) Contaminated air, water, food
(b) Contaminated equipments and
instruments
(c) Soiled linen
(d) Hospital waste (Biomedical
waste)
B. EndogenousB. Endogenous
source is the normalsource is the normal
flora or colonizers offlora or colonizers of
skin and other epithelialskin and other epithelial
surfaces transient orsurfaces transient or
residentsresidents
Shyam Kumar Mishra

Factors influencing the nosocomial infections
A. The microbial factors
- Characteristics of microorganisms
- Amount of inoculum
- Virulence
- Bacterial resistance
B. Host factors :
Patient susceptibility, immune status, Underlying disease,
the extreme of life (old age, infancy).
Patients with chronic disease (Leukemia, DM, TB, Renal disease)
C. Environmental factors
Crowded conditions, contaminate objects, water ,food
D. Diagnostic and therapeutic intervention
E. Intensive care units
– Medical, surgical, neonatal, burn units
Shyam Kumar Mishra

IMPORTANT EXTRINSIC RISK FACTORS FOR MAJOR
NOSOCOMIAL INFECTIONS
INFECTIONS RISK FACTORS
Urinary tract Indwelling catheter
Duration of catheterization
Pneumonia Endotracheal tube
Mechanical ventilation
Thoracoabdominal surgery
Nasogastric tube
Surgical wound Pre operative stay
Preoperative shaving
Duration of surgery
Degree of wound contamination
Presence of foreign body
Primary bacteremia Intravascular cannula
Duration of cannulation
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Risk factors for HA-UTI
• Duration of catheterization
• Long hospital stay
• Diabetes
• Malnutrition
• Female sex
• Improper catheter care
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● Previous antibiotic exposure, particularly to third generation cephalosporins
● Reintubation or prolonged intubation
● Mechanical ventilation
● Age >70 years
● Chronic lung disease
● Decreased consciousness
● Chest surgery
● Presence of an nasogastric tube
Risk factors for HAP
Shyam Kumar Mishra

• Diabetes
• Over 60 years of age
• Long duration of the surgical procedure
• Pre-existing infection at the site of the wound
• Systemic corticosteroids or treatment with other immunosuppressive drugs
• Malnutrition
• Preoperative nasal carriage or colonization at other sites with S. aureus
• Presence of a remote focus of infection
• Duration of preoperative hospitalization
• Preoperative preparation, shaving of hair from the site
Risk factors for SSI
Shyam Kumar Mishra

Mortality rate due to Nosocomial
infection (Argentina, 2003)
Types of infection (%)
Urinary Tract Infection 5.0
Catheter-related Blood
stream infection
25.0
Ventilator-associated
Pneumonia
35.0
Rosenthal VD, Guzman S, Orellano PW. Am J Infect Control 2003;31:291-5.Shyam Kumar Mishra

Length of hospital stay due to
nosocomial infection
TYPES OF
INFECTION
EXTRA DAYS EXTRA COST
(US $)
Pneumonia 5.9 5683
Blood stream 7.4 3517
Surgical site 7.3 3152
Urinary tract 1.0 680
All 4.0 2100
Emori TG, Gaynes RP. Clin Microbiol Rev 1993;6:429-442.
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Agents OF HAIAgents OF HAI
Virtually all microorganisms can cause nosocomial infectionsVirtually all microorganisms can cause nosocomial infections
Bacteria is the most common cause of nosocomial infection
• BacteriaBacteria
• VirusesViruses
• FungiFungi
• ParasitesParasites
Gram-positive bacteriaGram-positive bacteria
Staphylococcus aureusStaphylococcus aureus
Staphylococcus epidermidisStaphylococcus epidermidis
Enterococcus faecalisEnterococcus faecalis
Gram-negativeGram-negative
EnterobacteriaceaeEnterobacteriaceae
Pseudomonas aeruginosaPseudomonas aeruginosa
Acinetobacter baumanniAcinetobacter baumanni
Mycobacterium tuberculosisMycobacterium tuberculosis
VirusVirus
HBV, HCV, HIVHBV, HCV, HIV
Others: CMV, rubella, varicella,Others: CMV, rubella, varicella,
SARS, Rota virusSARS, Rota virus
FungiFungi
CandidaCandida
AspergillusAspergillus
Shyam Kumar Mishra

Antimicrobial resistance
1945 – Penicillin
1948 – Penicillin-resistant S.aureus
1959 – Methicillin
1960s - Beta lactamase enzyme, Temoniera (TEM)
1961 – Methicillin-resistant S. aureus
1983 - ESBL in Germany
1988 - Amp C Beta lactamase in Canada-Vancover
1990s – MBL
1996 - VISA in Japan reduced susceptibility to
Vancomycin in S. aureus
2002 – Vancomycin-resistant S.aureus
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Surveillance
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• Surveillance can be defined as the systematic, active on-
going observation of the occurrence and distribution of a
disease within a population and of the events that
increase or decrease the risk of the disease occurrence.
If the incidence, distribution and associations of a
disease are known, then resources can be targeted,
predisposing factors can be reduced or eliminated, and
the incidence of the disease reduced.
Shyam Kumar Mishra

Why surveillance???
• To reduce the incidence of HAI and thus to reduce the
associated morbidity, mortality, and costs.
– To assess magnitude of problem
– To monitor implementation of health programs
– To understand local epidemiology of the problem
– To assess changes in trend of disease or its distribution
– To identify specific groups at risk
– To enable predictions about pattern of occurrence of diseases
– To assess the impact of the programme intervention for control
of diseases
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SURVEILLANCE METHOD
ACTIVE PASSIVE
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Formal surveillance
(each patient to be assessed, often repeatedly, by trained staff)
(very expensive)
Therefore, surveillance is often done routinely by analysing
laboratory reports, or by informal ward visits, or by a
combination of the two.
However, laboratory reports are not always indicative of true
infection. Negative reports (or no report) do not always mean
infection is absent.
Nevertheless, active surveillance (case finding by the Infection
Control Nurse increased detection from approximately 25% of
defined infections to more than 85% in some studies.Shyam Kumar Mishra

Incidence and prevalence of
HAI
• The prevalence of HAI is the number of cases of active
HAI in a defined patient population either during a
specified period of time (the period prevalence) or at a
specified point in time (point prevalence).
• The incidence of HAI is the number of new cases of
disease that occur in the defined patient population
during a specified time period.
Shyam Kumar Mishra

Targeted surveillance
• Site-oriented surveillance
• Unit-oriented surveillance
• Priority-oriented surveillance
– Alert-condition surveillance
– Alert-organism surveillance
Shyam Kumar Mishra

Patient-based surveillance
a) Count HAI, assess risk factors, and monitor patient care
procedures and practices for adherence to infection
control principles
b) Requires ward rounds and discussion with caregivers
Laboratory-based surveillance
a) Detection is based solely on the findings of laboratory
studies of clinical specimens
Shyam Kumar Mishra

Prospective surveillance
a) Monitor patients during their hospitalization
b) For SSIs, also monitor during the post-discharge period
Retrospective surveillance
a) Identify infections via chart reviews after patient
discharge
Shyam Kumar Mishra

Risk-adjusted rates
a) Rates are controlled for variations in the distribution of
major risk factors associated with an event’s occurrence
b) Such rates allow inter- and intra-facility rate comparisons
Crude rates
a) Rates assume equal distribution of risk factors for all
events
b) Such rates cannot be used for inter-facility comparisons
Shyam Kumar Mishra

Data to collect
1. Demographic – name, date of birth, gender, hospital
identification number, admission date
2. Infection – onset date, site of infection, patient care
location of HAI onset
3. Risk factors – devices, procedures, other factors
associated with HAI
4. Laboratory – pathogens, antibiogram, serology,
pathology
5. Radiology/imaging – X-ray, CT scan, MRI, etc.
Shyam Kumar Mishra

Sources of data
1. Admission/discharge/transfer records, microbiology
laboratory records
2. Visits to patient wards for observation and discussion
with caregivers
3. Patient charts (paper or computerized) for case
confirmation
a) Laboratory and radiology/imaging results
b) Nursing and physician’s notes and consults
c) Admission diagnosis
d) History and physical examination findings
e) Records of diagnostic and surgical interventions
f) Temperature chart
g) Information on administration of antibiotics
Shyam Kumar Mishra

• Most infectious disease physicians,
infection preventionists and
epidemiologists agree that HAIs are
under-reported. Why?
Shyam Kumar Mishra

Post-discharge surveillance often poses
considerable logistic problems and may
add further expense to surveillance
activities.
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• Surveillance without action should be abandoned.
• Perform follow-up surveillance to monitor for
improvement following changes (“close the loop”).
SurveillanceSurveillance
ReviewReview
DisseminationDissemination
ActionAction
Shyam Kumar Mishra

Two components of sampling
1. From persons engaged within the hospital
– Doctor
– Nurses
– Ward attendant etc.
2. Environmental samples:
– water
– air sample
– I.V. catheters
– I.V.fluids
– Sutures used in the hospital
Other suspected objects
– floors
– walls
– surfaces
– sanitary, basins, sinks etc.
Shyam Kumar Mishra

EPIDEMIOLOGICAL MARKERS FOR NOSOCOMIAL INFECTION
• Biotyping
• Antibiogram
• Serotyping
• Bacteriophage typing
• Bacteriocin typing
• Dienes phenomenon
• Bettelheim reaction (colony incompatibility)
Shyam Kumar Mishra

• Plasmid analysis
• RFLP
• PCR-RFLP
• DNA/DNA hybridization
• DNA/RNA hybridization
• Pulse field gel electrophoresis
• Randomly amplified polymorphic DNA (RAPD)
• LCR
• Ribotyping
• Spoligotyping
• MLST
• Cloning
• Sequencing
Shyam Kumar Mishra

Prevention of Nosocomial
infections
 There is a Nosocomial infection control committee
(NICC) which includes:
Matron
Physician
Surgeon
Administrator
Microbiologist
Medical laboratory technologist
Pharmacist
House-keeping staff
Shyam Kumar Mishra

 Periodical training of staffs regarding
nosocomial infection control
 Immunizations for the staffs; PEPs
 Microbial monitoring of hospital:
Periodical exposure of culture plates/
swabbing (wards, ICUs, Operation theatre)
 Carrier detection: Microbial culture of
Nasal Swab, Hand Swab, Masks & gowns of
Surgeons, Physicians, Nurses and other
Staffs involved in Patient CareShyam Kumar Mishra

 Much attention needs to be paid to
Multidrug resistant (MDR) isolates.
 Status of MDR bacterial isolates should be
disseminated through scientific
conferences, newsletters, journals and
personal communication.
 Hospital infection control guidelines should
be prepared to investigate and control
nosocomial infections.
Shyam Kumar Mishra

Use of color-coded containers for
segregation of laboratory and hospital wastes
Proper disposal of hospital waste products
Hospital building must meet ISO standard
(Ventilation, Water, Waste)
Shyam Kumar Mishra

Role of Microbiologist
• Developing guidelines for appropriate collection,
transport and handling of specimens.
• Ensuring that the laboratory practice meet appropriate
standards.
• Ensuring safe laboratory practice to prevent infections in
staff
• Perform AST of clinical isolates
• Monitor sterilization, disinfection procedures /
environment where necessary
• Timely communicate results to Infection Prevention
Committee
• Epidemiological typing of hospital microorganisms
• Follow Antibiotic stewardship
Shyam Kumar Mishra

• Antimicrobial stewardship refers to coordinated
interventions designed to improve and measure
the appropriate use of antimicrobials by
promoting the selection of the optimal
antimicrobial drug regimen, dose, duration of
therapy, and route of administration.
Shyam Kumar Mishra

Infection Prevention (IP)
“Infection prevention largely depends on
placing the barriers between a susceptible
host and microorganisms”
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HAND WASHING
“Hand washing is the most practical
procedure for preventing cross-
contamination (person to person). Hand
washing may be the single most
important procedure for preventing
infection.”
Global handwashing Day
(15th October)
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1. Wash your hands when they are dirty and
BEFORE eating
2. DO NOT cough into your hand
3. DO NOT sneeze into your hands
4. Above all, DO NOT put your fingers into
your eyes, nose or mouth
Shyam Kumar Mishra

HAND WASHING TECHNIQUE
Source: World Health Organization. Regional Office for Western Pacific.
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SIR WILLIAM OSLER-
“Soap, Water and common sense are the
best disinfectants in the hospital.”
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Nosocomial infection and its surveillance

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