Transcript EPIDEMIOLOGY OF NOSOCOMIAL INFECTIONS

EPIDEMIOLOGY OF NOSOCOMIAL
INFECTIONS (NCIs) PART-1
Dr. A.K.AVASARALA MBBS, M.D.
PROFESSOR & HEAD
DEPT OF COMMUNITY MEDICINE &
EPIDEMIOLOGY
PRATHIMA INSTITUTE OF MEDICAL
SCIENCES, KARIMNAGAR, A.P..
INDIA: +91505417
[email protected]
DEFINITION
• Nosocomial infection is
an infection that is not
present or incubating
when a patient is
admitted to a hospital
LEARNING OBJECTIVES
LEARNER SHOULD LEARN
1. PUBLIC HEALTH IMPACT OF
HOSPITAL ACQUIRED INFECTIONS.
2. EPIDEMIOLOGY, PREVENTION,
SURVEILLANCE AND CONTROL
STRATEGIES
3. INDIAN SITUATION OF THE PROBLEM
PERFORMANCE OBJECTIVES
LEARNER SHOULD BE ABLE TO
1. Estimate the extent and nature of nosocomial
infections in his hospital
2. Identify the changes in the incidence of
nosocomial infections and the pathogens that
cause them.
3. Provide his hospital with comparative data on
nosocomial infection rates.
4. Develop efficient and effective data collection,
management and analysis methods for his
hospital.
5. Conduct collaborative research studies on
nosocomial infections in his hospital.
TYPES BY ORIGIN
1.Endogenous:
Caused by the organisms that are
present as part of normal flora of
the patient
2. Exogenous:
caused by organisms acquiring by
exposure to hospital personnel,
medical devices or hospital
environment
TYPES OF NCI BY SITE
1. Urinary tract infections (UTI)
2. Surgical wound infections
(SWI)
3. Lower respiratory infections
(LRI)
4. Blood stream infections (BSI)
EPIDEMIOLOGICAL INTERACTION
Intrinsic host susceptibility
Age, Poor nutritional status,
Co morbidity, severity of
underlying disease
Agent factors
varieties of organisms
Institutional and human
Reservoirs & their
virulence
Environmental factors
hospital location,
diagn procedures,
immunosuppressive,
chemotherapy, antibiotics,
med & surgical devices,
exposure to infected patients
or health workers,
asymptomatic carriers
DISEASE BURDEN
• 5-10% in developed countries
• 10-30% IN DEVELOPING COUNTRIES
• Rates vary between countries, within
the country, within the districts and
sometimes even within the hospital
itself, due to
1) complex mix of the patients
2) aggressive treatment
3) local practices
INDIAN SCENARIO
HOSPITAL INFECTION
SOCIETY (HIS), INDIA
• Ten to 30 per cent of patients
admitted to hospitals and
nursing homes in India, acquire
nosocomial infection as against
an impressive five per cent in
the West, according to member
of HIS, Rita Dutta – Mumbai.
HINDUJA, HOSPITAL
Dr F D Dastur, Director, Medical
education, P D Hinduja, Hospital:
“nosocomial control programme is at
a nascent stage in Indian hospitals,
with some yet to establish a central
sterilization and supply department
(CSSD) and appoint an infection
control nurse”
ASIAN HEART INSTITUTE (AHI)
Dr Vijay D Silva, director, critical care,
Asian Heart Institute (AHI):
“Suggestions to strengthen the
infection control programme is turned
down by the management of most
hospitals as spending on infection
control does not generate revenue.”
INCIDENCE
• Average Incidence - 5% to 10%, but
maybe up to 28% in ICU
• Urinary Tract Infection - usually
catheter related -28%
• Surgical Site Infection or wound
infection -19%
• Pneumonia -17%
• Blood Stream infection - 7% to 16%
INCIDENCE
• Depends upon
1. Average level of patient risk
depends upon intrinsic host
factors and extrinsic
environment factors
2. Sensitivity &specificity of
surveillance programmes
AGE RANKS OF NCIs
Ranks in
infants
Ranks in
children
Ranks in
adults
1) SKIN
2) LRI
3) BSI
4) UTI
5) SWI
1) SKIN
2) LRI
3) BSI
4) UTI
5) SWI
1) UTI
2) LRI
3) SWI
4) BSI
PEDIATRIC INFECTIONS
• Epidemiology is Unique
• Rates of infection by site and
pathogen differ from those reported
in adults
• Pathogen distribution is also
different – S. aureus in children and
E. Coli in adults
• Pediatric viral URI&LRI far exceeds
that caused by bacterial ones.
CONSEQUENCES OF
NOSOCOMIAL INFECTIONS
1. Prolongation of hospital stay:
Varies by site, greatest with pneumonias
and wound infections
2. Additional morbidity
3. Mortality increases - in order - LRI, BSI,
UTI
4. Long-term physical &neurological
consequences
5. Direct patient costs increasedEscalation of the cost of care
ECONOMICS OF NCIS
• Extra cost of NCI consequences
• Bed,
• Intensive care unit stay,
• Hematological, biochemical,
microbiological and radiological tests,
• Antibiotics & other drugs,
• Extra surgical procedures
• Working hours
COMMON BACTERIAL
AGENTS
Pseudomonas
(9%)
aeruginosa
Enterococcus (10%)
Coag-neg staphylococcl
(11%)
E-coli
(12%)
Staphylococcus aureus
(13%)
Other
(45%)
KASTURBA MEDICAL COLLEGE, MANGALORE
• Drug resistance was more common with
MRSA nosocomial strains.
• All MRSA strains were resistant to penicillin
and sensitive (73.8 percent), ciprofloxacin
(78.6 percent) gentamicin (84.7 percent) and
trimethoprim-sulphamethoxazole (95.7
percent).
• Bhat KG; Bhat MV
• Department of Microbiology, Kasturba Medical
College, Light House Hill Road, Mangalore 575001, India
• Prevalence of nosocomial infections due to
methicillin resistant staphylococcus aureus in
Mangalore, India
• Biomedicine. 1997; 17(1): 17-20
CHRISTIAN MEDICAL COLLEGE,
VELLORE
• Says Dr J Kang, professor of
microbiology at CMC:
“ While MRSA is the troublemaker in
most cases, at Vellore nosocomial
infection due to MRSA is only five per
cent because of genotyping.”
FUNGI
• Due to increased antibiotic use &host
susceptibility
• Candida species– most common, causing
BSI (38% mortality)
• Changing bacterial & fungal spectrum in
the hospital reflects the increased use,
particularly of the newer antibiotics
• Development of resistance (MRSA, VRE,
MDRTB)
• Overcrowding & understaffing of nursing
units increased the rates of infections
(MRSA colonization)
VIRUSES
•
•
•
•
•
CMV, HERPES SIMPLEX
V-Z VIRUSES
HEPATITIS VIRUSES- A, B ,C
HIV
INFLUENZA, PARA INFLUENZA,
R.S.VIRUS, ROTAVIRUS
EPIDEMIOLOGY OF VIRAL
INFECTIONS
• Mostly affects Resp &
Gastrointestinal tracts (90%)
whereas bacterial infections attack
these systems to about 15% only.
• Pediatric viral URI & LRI far
exceeds that caused by bacterial
ones.
PLACE DISTRIBUTION
ICU RISK
•
•
•
•
PROLONGED ICU STAY
MECHANICAL VENTILATION
TRAUMA
URINARY CATHETER,VASCULAR
CATHETER
• STRESS ULCER PROPHYLAXIS
•
•
•
•
•
•
•
•
•
RISK FACTORS
Malnutrition
Sex (females with UTI)
Extremes of age
Infections at remote site
Use of antibiotics, H2 blockers,
sedatives
Diabetes, Renal Failure and causes of
immunosuppression
Altered mental status
Surgery
ICU setting, endotracheal intubation
with mechanical ventilation
MODES OF TRANSMISSION
•
•
BY CONTACT
1) Direct - between Patients and between
patient care personnel
2) Indirect - contaminated inanimate objects
in environment (Endoscopes etc)
3) Droplet infections by large aerosols
B) THRO COMMON VEHICE like Food, Blood &
blood products, Diagnostic reagents,
Medications
C) AIRBORNE e.g. legionellosis, aspergillosis
D) VECTORBORNE – by flies
UTI
• Contribute to one third of NCI s
• 80% due to catheter
• 5-10% due to urinary tract
manipulation
• Prolongs hospital stay by 1-2 days
BACTERIURIA (BU)
• PERIURETHRAL COLONIZATION
WITH POTENTIAL PATHOGENS
INCREASES BU BY THREE FOLD
• LATE CATHETERIZATION
INCREASES BU
RISK FACTORS FOR BU
• DURATION OF CATHETRIZATION
• MICROBIAL COLONIZATION
• NO PRIOR ANTIBIOTIC USE
• FEMALE GENDER
• DIABETES MELITUS
• ABNORMAL SERUM CREATININE
• FAILURE TO USE URINOMETER (DRIP CHAMBER)
CATHETER & UTI
• Presence of catheter leads to
increased incidence of Bacteriuria
• Short term catheter use (urinary
output measurement, surgery )
increase BU by 15%
Long term catheter use (retention,
obstruction, incontinence) increases
BU by 90%
CATHETER USE COMPLICATIONS
• MORE SEEN IN MEN (BACTEREMIA DUE
TO UTI 15%)
• SHORT TERM USE - EVERS,
SYMPTOMATIC UTI, BACTEREMIA
• LONG TERM CATHETER USE - ABOVE +
CATHETER OBSTRUCTION, URINARY
STONES, PERIURINARY INFECTIONS,
RENAL FAILURE, BLADDER CANCER
SURGICAL WOUND INFECTIONS
(SWI)
Incidence varies from 1.5 to 13 per
100 operations.
• It can be classified as
1. Superficial incisional SWI
2. Deep incisional SWI and
3. Organ/Space SWI.
EPIDEMIOLOGY OF SWI
• HOST FACTORS
OLD AGE
• OBESITY
• CURRENT INFECTION AT ANOTHER
SITE
• PROLONGED POST OPERATIVE
HOSPITALIZATION
•
SOURCES OF INFECTION
1. DIRECT INOCULATION FROM
PATIENT’S FLORA
2. CONTAMINATED HOST TISSUES
3. HANDS OF SURGEONS
4. AIRBORNE TRANSMISSION
5. POST- OPERATIVE DRAINS/CATHETERS
LOWER RESPIRATORY INFECTIONS
(LRI)
MOSTLY SEEN IN ICU
RISK FACTORS
1.
2.
3.
4.
5.
6.
7.
8.
9.
TRACHEOSTOMY,
ENDOTRACHEAL INTUBATION, VENTILATOR,
CONTAMINATED AEROSOLS, BAD EQIPPMENT,
CONDENSATE IN VENTILATOR TUBING,
ANTIBIOTICS,
SURGERY,
OLD AGE ,
COPD,
IMMUNO SUPPRESSION
LOGISTIC REGRESSION OF
CONTRIBUTING FACTORS
• TIME FROM ADMISSION TO PNEUMONIA
+++++++
• PROLONGED HOSPITAL STAY +++++
• NASOGASTRIC INTUBATION +++
• AGE ++
• PRIOR USE OF MECHANICAL
VENTILATORS++
• POST TRACHEOSTOMY STATUS++
• IMMUNOSSUPPRESSION OR
LEUKOPENIA++
• NEOPLASTIC DISEASE +
COHORT STUDY
• ON PNEUMONIA PATIENTS WITH
VENTILATORS
• ATTRIBUTABLE RISK 27%
• DEATH RISK 2%
• LRI IS DIRECTLY RELATED TO THE
LENGTH OF STAY
RISK FACTORS FOR
DIARRHEAS
•
1.
2.
3.
4.
5.
BY CLOSTRIDIUM DIFFICILE
OLD AGE
SEVERE UNDERLYING DISEASE
HOSPITALISATION FOR >1 WEEK
LONG STAY IN ICU
PRIOR ANTIBIOTICS
BLOOD STREAM INFECTIONS
(BSI)
• PRIMARY = ISOLATION OF BACTERIAL
BLOOD PATHOGEN IN THE ABSENCE OF
INFECTION AT ANOTHER SITE
• SECONDARY = WHEN BACTERIA ARE
ISOLATED FROM THE BLOOD DURING
AN INFECTION WITH THE SAME
ORGANISM AT ANOTHER SITE i.e. UTI,
SWI OR LRI
BACTEREMIA (BSI)
BSI ARE INCREASING PRIMARILY DUE TO
INCREASE IN INFECTIONS WITH GM+VE
BACTERIA & FUNGI
MOST COMMON IN NEONATES IN HIGH
RISK NURSERIES
MORTALITY RATE FOR NOSOCOMIAL
BACTEREMIA IS HIGHER THAN FOR
COMMUNITY ACQUIRED BACTEREMIA
SOURCES OF BSI
• IV CATHETERS, INTRINSIC IV FLUID
CONTAMINATION
• MULTIDOSE PARENTERAL MEDICATION
VIALS
• VASCULAR CATHETER RELATED
INFECTIONS, CONTAMINATED
ANTISEPTICS, CONTAMINATED HANDS OF
HEALTH CARE WORKERS
• AUTOINFECTION FOLLOWING
HEMATOGENOUS SEEDLING - RISK
INCREASES WITH LONGER DURATION >72
HOURS