Infection acquired while in hospital

1
Introduction

Infection acquired while in hospital
Hospital infection


Infection acquired in the community 8-16
of hospital patients acquire infections while
in hospital
Hospital acquired infections are referred as
nosocomial infections Hospital staff
are at risk from diseases such as tuberculosis or
hepatitis
2
Types of hospital acquired infectios
1-
Surgical site infection (SSI)

2-
Urinary tract infection (Catheter-related
infection)
3- Respiratory tract infection (Ventilator-related
infection) 4- Blood stream
infection

5-
Gastrointestinal infection


6- Others


3
The infection cycle
Source Of Infection
Mode Of Transmission
The
Suscptible Host
SOURCE OF INFECTION It is the place
from which the infectious agents directly
gain access to the susceptible host
4
Source of infection
Endogenous Exogenous
The organisms belong to The
organisms are derived species of the normal
from a source other than
human flora
the effected host


5
Endogenous
source
Nares Skin
Oropharynx GIT S.
aureus Coagulase negative S. pneumonia
Enterobacteriace
staphylococci
Enterococci
Cl.
difficile
Candida
6
Exogenous source Persons

Patients
Attendants Nurses
Doctors Hospital environment



Air Water
Disinfectants Towels
Istruments



Cannulae Renal dialysis machine
Endoscopes Blood and its products


7
Mode Of Transmission
Direct
Contact Indirect

Common vehicle
Droplet Air-born

Droplet nuclei
Vector-born House flies

8
Contact transmission
Patient
---------- Patient a- Direct


Healthcare worker --------- Patient
Healthcare worker
Patient
---------------- Patient b- Indirect


Inadequately decontaminated

Patient -------------------- Patient

instruments c- Common Vehicle
Ventilator , Dialysis machine

9
Air-born transmission Droplet
Droplet nuclei
short distance
long distance
Source------------Victims
Source-------------Victims

Less than 5 um in diameter

Produced from evaporated droplets

Remain suspended for long periods e.g
Group A streptococci e.g-M.
tuberculosis
10
Vector-born transmission Biological
vectors e.g- Mechanical transmission of
salmonella by house flies
11
self infection
Self infection Infected/colonized
other patient
Patient or staff member
or member of staff Cross infection
12


Environmental infection

air
Dust
Water
ventilators
Food
washbowls
urinals
Intravenous fluid equipment
Disinfectants
Solutions
13
Combination
Air/dust
Staph. sepsis
Nose
Self-infection
Wound infection
Hospital environment
contaminated with
hospital S. aureus
Via hands of a nurse
Wound infection
3rd. patient environmental infection

2nd. patient Cross infection
1st. Index case
14
Susceptible Host

Hospitalized patients are at high risk infections
due to
Intrinsic factors Extrinsic
factors
Surgical Advanced age
Irrational antibiotics

infection Loss of skin integrity
Inadequate sterilization
Malnutrition
Preparation of patient

Obesity Type of
procedure


Advanced age
Indwelling urinary

UTI Female
catheterization
Severity of the disease


15
Factors governing the occurrence of
hospital infection
The organism

Type
Virulence Dose Duration of exposure
The patient

General host defences
Local host defenses
Age
Intact skin or
mucosa Nature
of the disease Local
immunoglobulin A Control of
hospital infection

Sterilization Disinfection of contaminated
items Disposal of
infected rubbish or linen
Aseptic
techniques in the operating theater and the wards
The education of in
hospital hygiene

16

• Important nosocomial infection pathogens
  
• Methicillin-resistant Staphylococcus aureus
  (MRSA)
• Methicillin-resistant
  coagulase-negative staphylococci
  
• 
  
  
• 
  
  
• Vancomycin-resistant
  enterococci (VRE)
  
• 
  
  
• 
  
  
• Penicillin-resistant
  pneumococci

17
Surgical wound
infection Causative
organisms


Streptococcus pyogenes



aureus

Staphylococcus

epidermidis
Gram negative
bacilli E. coli , Klebsiella ,
Pseudomonas , Proteus
Anaerobic
streptococci .
Clostridia (Cl.
Tetani , Cl. Welchii) Bacteroids
Anaerobic organisms
18
Prevention of surgical wound infection

Adequate sterilization

Sterile operating room

Surgical discipline
Preparation of
the patient
Proper surgical technique
Post-operative wound care

Proper use of antibiotics

19
Investigation of an outbreak of surgical wound
infection
Typing the infecting organism


The same surgical room


The same surgical team




Number of the isolated organisms


20
Infection control program
Hospital committee for I C
Infection control

organization
Infection control team

To
improve the quality of patient care Goal


To reduce the cost of
patient care
To control and prevent nosocomial
infection Objectives


To minimize of cross infection in hospitals
21
Elements of Infection Control program
1- surveillance and reporting

a- Patient infection




pre-employment screening
b- Healthcare workers infection Follow-up
of employment

Exposure to communicable diseases c-
Equipment, procedures and practices


d- Hospital environment


Notification e- Communicable
diseases Data collection

Analyses and reporting
22
2- Control and prevention


a- Teaching and
consulting

I C
polices and procedures b- Administrative
activities

Delegate
responsibilities
to I C team members

Antibiotic policy
c- Special studies
Study of risk factors


Cost-effectiveness studies
23

• Anaerobic infections
• 
  Characteristics of anaerobic infection
  
  
• A foul odour pus
  
  
• 
  Abscesses of Lung
  
• Tend to form closed-space lesions
  
  
• 
  Abscesses of
  brain
• 
  
  
• 
  Reduced blood supply
• Favoured by
  Necrotic tissues
  
• 
  Low oxidation-reduction potential
• 
  Special collection methods
  
• It is essential to use
  Transport media
• 
  Sensitive techniques and media
  
• 
  
  
• Mixed infection is common
  
  

24
Classification of anaerobic bacteria
Spore-forming
Clostridium species

Bacteroides
Gm-negative bacilli


Fusobacterium

Actinomyces Non spore-forming Gm-positive
bacilli Eubacterium

Lactobacilli
Gm-positive cocci
Peptostreptococci
Gm-negative cocci Veillonella
25

• Sites of important anaerobic infections
• Necrotizing pneumonia
  lung abscess
• 
  
• Central nervous system
  brain abscess
• Intra-abdominal and pelvic abscesses
  
• 
  
  
• 
  intrauterine abscess
• Genital infections
  
  
• pelvic
  abscess
• Mouth
  periodontal
  infections
• 
  
• Upper respiratory tract
  sinusitis and otitis media
• 
  
  

26

• Diagnosis of anaerobic infections
• 
  Aspirates
• Collection and transport of specimens
  
  
• 
  Tissues specimens
• Direct microscopic examination
  
  
• 
  
• Culture methods Anaerobic
  conditions
  
• 
  Gm-staining reactions
• Biochemical reactions
  
• Growth is identified by Gas-liquid
  chromatography
• 
  Specific antibodies , fluorescent
  antibodies
• DNA hybridization
  techniques

27
Antimicrobials for anaerobic infections
Clindamycin
Metronidazole
Chloramphenicol
Penicillin in high doses