بسم اللة الرحمن الرحيم. Nosocomial Infection and Infection Control By Prof. Dr....
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Transcript of بسم اللة الرحمن الرحيم. Nosocomial Infection and Infection Control By Prof. Dr....
بسم اللة الرحمن بسم اللة الرحمن الرحيمالرحيم
Nosocomial Infection and Nosocomial Infection and Infection ControlInfection Control
ByByProf. Dr. Mohamed I. Prof. Dr. Mohamed I.
BassyouniBassyouni
SummarySummary Sources of infection Transmission of Infection Patterns of Infection Outbreaks & Epidemiological typing Infection Control
◦ General Principles: Hospital & Community◦ Who’s who
Hospital-acquired infection◦ Syndromes◦ Rogues’ gallery◦ Control of Cross-Infection◦ Risks from Hospital Staff
Final words
INFECTIONINFECTIONDefinition Is entry into and
multiplication of an infectious agent (pathogen) in the tissues of the host resulting in tissue damage/injurious effects.
Subclinical – unapparent.Clinical – apparent. COLONIZATION The presence of microorganism in or
on a host with growth and multiplication but without tissue invasion.
foodsalmonellosis, campylobacter
Humans Animals(zoonoses)
Environment
clinical casee.g. measlestuberculosis
,
convalscent carriere.g. typhoid diphtheria hepatitis B
symptomless carrier e.g. typhoid, hepatitis
auto-infectione.g. UTIcandidiasis
clinical casee.g. rabies psittacosis
carriere.g. salmonella leptospirosis
vector-bornee.g. malaria Lyme disease plague
soile.g. tetanus
watercryptosporidiosis, giardia, choleraairborne
e.g. legionellosis
Sources of infectionSources of infectionWhere do patients get their infections from...?Where do patients get their infections from...?…in the community…in the community
Sources of infectionSources of infectionWhere do patients get their infections from...?Where do patients get their infections from...?…in the hospital…in the hospital
foodsalmonellosis
HumansCross-infection
Environment
clinical casee.g. chickenpoxstreptococcal pharyngitiswound infection
symptomless carriere.g. MRSA(Gentamicin-resistant) gent-resistant GNRs
auto-infection
e.g. some Staph aureus
wound infections
IVIe.g. Staph aureus,diphtheroids, staph epidermidis
ventilator e.g.Pseudomonas
air/dustStaph aureus , legionelladisinfectants, solutions etc
eg. Pseudomonas
endoscopese.g. mycobacteria
H. pylori
Humans
Transmission of InfectionTransmission of InfectionDefinitions of terms by exampleDefinitions of terms by example
Salmonella gastro-enteritis Reservoir
◦ more commonly animal gut flora
◦ less commonly human cases & carriers
Source or Vehicle◦ food from affected animals◦ contaminated food
Transmission of InfectionTransmission of InfectionDefinitions of terms by exampleDefinitions of terms by example
S. aureus wound infectionReservoir
◦ Human nose & skinSource or Vehicle
◦ Hands of health care workers
insert here
Patterns of InfectionPatterns of Infection
DefinitionsDefinitions
Sporadic ◦ rare infections, occurring now and then, without any
particular pattern e.g. gas gangrene, or Strep. pyogenes wound
infectionsEpidemic
◦ A sudden unexpected rise in number of infections caused by a particular pathogen
◦ Can range from the small scale e.g. a few individuals
◦ up to nationwide, e.g. The bovine spongiform encephalopathy (BSE) also
known as mad cow disease epidemic in UK
Patterns of InfectionPatterns of InfectionDefinitionsDefinitions
Outbreak ◦ commonly used to mean a limited epidemic, e.g. in
a hospital wardPandemic
◦ a world-wide epidemic◦ e.g. HIV or influenza
Endemic implies a constant significant number of infections indefinitely ◦ e.g. methicillin-resistant S. aureus is endemic to
many hospitals
e.g. an outbreak of salmonella gastro-enteritis
No. of new cases
Day
Epidemic infection or outbreak
Introduction of pathogen
followed by point source outbreak with abrupt start
outbreak sputters on due to limited human-to-
human spread
Patterns of InfectionExamples
Days
e.g. S. aureus wound infections in a hospital
Endemic infection continuous level of infection
predominantly due to human-to-human spread (cross-infection)
Patterns of InfectionPatterns of InfectionExamplesExamples
Outbreaks & Epidemiological Outbreaks & Epidemiological typingtyping
Why type organisms ?◦ do you have an outbreak or just an increase in
endemic or sporadic infection ? e.g. S. aureus infections in surgical unit
◦ identification of the source or extent of outbreak may have legal importance, e.g. close down restaurant
◦ identification of more virulent strains,Typing methods show whether isolates same
or different◦ Biochemistry, Antibiogram, Phage typing,
Serotyping, Molecular methods
Infection ControlInfection ControlGeneral PrinciplesGeneral Principles
Remove reservoir or source of infection Interrupt transmission of infection Increase host resistance to infection
Infection Control Infection Control in the communityin the community
Remove reservoirs & sources◦ Human-to-human
Case finding & treatment e.g. TB
Contact tracing Sexually Transmitted Disease (STDs), diphtheria, TB,
meningitis
◦ Animals Culling of infected animals
E.g. TB, Brucella
◦ Environment Clean water, good housing
Infection Control Infection Control in the communityin the community
Interrupt transmission◦Human-to-human
avoid overcrowding changes in behaviour (e.g. safe sex) isolation of infectious cases (e.g. from
school, work)
◦Animals & Environment Food hygiene, vector control, animal
vaccination & treatment, “poop-scooping”
Infection Control Infection Control in the communityin the community
Increase host resistance◦Improved diet◦Vaccination◦Chemoprophylaxis
Meningitis, diphtheria, TB
Nosocomial InfectionsNosocomial Infections The National Nosocomial
Infections Surveillance System (NNIS) defines a nosocomial infection as a localized or systemic condition 1) that results from adverse reaction to the presence of an infectious agent(s) or its toxin(s) and 2) that was not present or incubating at the time of admission to the hospital.
Hospital-acquired InfectionHospital-acquired Infectionwhy worry?why worry?
10-15% of patients will get infected during a stay in hospital
Costs >£1 billion per year in UKA single large outbreak can cost thousand of
billionsEffects of nosocomial infection
◦ Increased mortality & morbidity◦ Prolonged hospital stay◦ Increased drugs bill◦ Increased staffing costs◦ Demoralising for staff & patients◦ Decreased public confidence in hospitals & doctors
Why is hospital-acquired infection different Why is hospital-acquired infection different from community-acquired infection?from community-acquired infection?
Many patients have impaired immunity◦ After anti-cancer chemotherapy◦ After transplants◦ Extremes of age
Many patients have impaired normal physiological defences◦ Breaches in skin◦ Implanted foreign bodies (biofilms)◦ Impaired phsyiology (Peristalsis, mucociliary escalator)
Many vulnerable patients in close proximity to each other for prolonged periods of time
Why is hospital-acquired infection different Why is hospital-acquired infection different from community-acquired infection ?from community-acquired infection ?
There is a distinct hospital flora◦ "ordinary" pathogens
e.g pnemococci, E. coli, S. aureus, can all cause disease both inside and outside hospital
◦ opportunists only cause infection in patients with impaired immunity e.g Serratia marsecens, Xanthomonas maltophilia, S.
epidermidis, Corynebacterium jeikeium
◦ multi-resistant bacteria overlap with previous groups selected for in a darwinian fashion by antibiotic usage in
hospitals include opportunists which are inherently multi-resistant (e.g.
Xanthomonas maltophilia) and multi-resistant varieties of common organisms, e.g. MRSA, gent-resistant E. coli
Infection Control Infection Control in hospitalin hospital
Remove reservoirs & sources◦Human-to-human
Discharge infectious patients, e.g. with MRSA
Treat & decontaminate patients
◦Environment Control of Legionella Ward hygiene & cleaning Hospital design
Infection Control Infection Control in hospitalin hospital
Interrupt transmission◦Human-to-human
Hand washing Ward routine (e.g. wet mopping) Aseptic technique Sterilisation & disinfection Isolation procedures
◦Environment Food hygiene, pest control, theatre
design
Infection Control Infection Control in hospitalin hospitalIncrease host resistance
◦Good nutrition [e.g. total parenteral nutrition (TPN) in Intensive Treatment Unit (ITU)].
◦Restore normal physiology as quickly as possible Remove lines, catheters ... etc
◦Vaccinate (e.g. hepatitis B)◦Correct underlying defects
E.g. control diabetes
◦Stimulate immunity (e.g. Granulocyte macrophage colony-stimulating factor GM-CSF)
Infection Control Infection Control who’s whowho’s who in hospitalin hospital
Infection Control DoctorMicrobiologist Infection Control Nurses Infection Control Committee
◦ Formulate policies waste disposal, theatre design, food hygiene ... etc
◦ Surveillance of infection◦ Management of outbreaks◦ Staff education◦ Power to close wards and even whole hospitals
The committee of a large hospital should have representatives from all the major departments which may be concerned with the control of infection.
It should:- 1- Discuss any problems brought to them by infection
control doctor, nurse or other members of the committee. 2- Take the responsibility for major decisions. 3- Be given reports on current problems and on incidence of
infection. 4-Arrange interdepartmental co-ordination and education in
the control of infection. 5- Introduce, maintain and when necessary modify policies. 6- Advise on the selection of equipment for the prevention
of infection (e.g. sharps disposal boxes, etc.). 7- Make recommendations to their committees.
Action at the time of an Action at the time of an Outbreak Outbreak of of InfectionInfection 1- Arrangements for the clinical care of patients. 2- Adequate channels for communication should be set up
and a decision made as to who will be responsible for the communication with the media.
3- Assessment of the situation should be made. 4- Isolation of infected patients. 5- Introduction of additional control of infection techniques in
affected wards, closure of a ward and thorough cleaning after discharge of the last patient before re-opening.
6- The allocation of beds. 7- An epidemiological survey should be undertaken to provide
evidence of time and place where infection was acquired. 8- Surveillance of contacts-who may be incubating the
disease ( this include clinical surveillance, laboratory screening and typing ).
9- Bacteriological search for source of infection; examination of all staff and patients for carriage to see whether the same phage type of S. aureus is isolated from all infections.
10- Survey of methods, equipment and buildings. 11- The infection control or occupational health nurse will
discuss the situation with the head of the departments to relieve anxieties and indicate any necessary procedures.
12- The requirement for assistance should be assessed at each meeting and advice sought as necessary.
Why do we need Why do we need Typing ?Typing ?1- Prompt and appropriate
treatment.2- Improved patient outcomes.3- Reduced length of hospital stays.4- Improved cost-effectiveness.5- Identify local outbreaks.6- Identify epidemic/endemic clones.7- Understand epidemiology of
diseases.8- Understand microbial evolution.
How to do Typing ?How to do Typing ?
1- Choose the microbial isolates which need typing.
2- Conditions for all isolates should be the same;
a- Same culture age and type. b- All of them should be processed
together. c- In the same media manufacturer batch. d- With the same reagent manufacturer
batch. e- In the same incubator.
The typing methodsThe typing methods PHENOTYPIC METHODS - Susceptibility testing the study of the different
antimicrobial agents. Dilution Susceptibility tests involves inoculating media
containing different concentrations of the drug broth or agar with lowest concentrations showing no
growth is the Minimal inhibitory concentration (MIC). If broth used tubes showing no growth can be subcultured
into drug-free medium, broth which microbe can’t be grown is the Minimal Bactericidal concentration (MBC).
Disk Diffusion Tests; disks impregnated with a specific drugs are placed on agar plates inoculated with the tested microbe. Drugs diffuses from the disk into the agar, establishing concentration gradient, we observe clear zones (no growth) around the disks.
Kirby-Bauer agar disk diffusion; Paper disks containing an antibiotic is placed on lawn of bacteria, then incubated overnight. The diameter of the zone inhibition is inversely related to MIC (used to establish interpretive breakpoints). Standardized for commonly isolated rapidly growing organisms.
E-test :- Strips containing a gradient of antibiotics are placed on lawn of bacteria and incubating overnight. MIC is determined at a point where a zone of inhibition intersects scale on strip. In general MIC quantitative result is better than qualitative result (sensitive or resistant) because it gives a wide range of results.
- Phage typing is the effect of different bacteriophages on the bacteria.
- Biochemical typing Is the effect of biochemical reaction from the bacteria.
Coagulase typing ( positive or negative ).
- Serological typing is the study of the different antigenic types of bacteria e.g. the most common serotypes of Neisseria meningitidis are A,B.C, W135 and Y.
GENOTYPING METHODS - Pulse filled Gel Electrophoresis (PFGE). Is the study of
the different filled bacterial DNA by cut it by enzymes making different bands for the bacteria.
- Polymerase Chain Reaction (PCR) is the study of different targets (genes) in bacterial DNA.
Hospital-acquired InfectionHospital-acquired InfectionSyndromesSyndromes
Nosocomial UTI◦~30% of hospital infections◦Usually catheter associated
Asymptomatic colonisation common
◦Treatment of clinical infection often requires catheter removal BUT only under antibiotic cover!
Hospital-acquired InfectionHospital-acquired InfectionSyndromesSyndromes
Chest infection ◦ ~20% of nosocomial infections◦ Gram-negative pneumonia
Problem in critically ill & immunocompromised patients◦ Legionellosis
Vigilance is necessary for early detection of outbreaks Control by
raising the hot water temp regular cleaning & inspection of water & air-cooling systems
Hospital-acquired InfectionHospital-acquired InfectionSyndromesSyndromes
Wound Infections ◦~20% of nosocomial infections◦Rates vary depending on whether
“clean” or “dirty” surgeryBlood-stream Infections
◦~30% of nosocomial infections◦Especially device-associated
infection◦Treatment: remove the foreign body
Hospital-acquired InfectionHospital-acquired InfectionRogues galleryRogues gallery
Methcillin-resistant Staphylococcus aureus◦ MRSA◦ Infection Requires vancomycin treatment◦ Colonisation requires isolation, decontamination
with mupirocin and betadineVancomycin-resistant enterococci
◦ VRE, includes E. faecalis and E. faecium◦ Low grade pathogens◦ If also multi-drug resistant treatment can be
difficult E. faecium but not E. faecalis treatable with
quinupristin & dalfopristin (Synercid)
Hospital-acquired InfectionHospital-acquired InfectionRogues’ galleryRogues’ gallery
Clostridium difficile◦ Causes Antibiotic-associated colitis◦ Can cause outbreaks in hospitals◦ Patients should be isolated
Gentamicin-resistant GNRs◦ Require treatment with expensive drugs such as
amikacin and imipenem◦ Patients should be isolated◦ Can cause outbreaks e.g. on oncology wards or in
ITUFungal infection
◦ Aspergillus fumigatus and Candida albicans can cause nosocomial outbreaks
Control of Cross-Control of Cross-Infection Infection
Handwashing is paramount!◦ even for Consultants!◦ wash your hands before
& after examining patients, especially if you look at undressed wounds
◦ Alcoholic hand rubs may provide a convenient alternative to soap and water, especially where sinks are in short supply or during an outbreak
Control of Cross-Infection Control of Cross-Infection Isolation of infectious patients
◦ whenever you admit or assess a patient think: does this patient need to be isolated?
◦ general precautions Side-room isolation (or cohort nursing or isolation ward) Hand-washing on entry & exit Use of aprons and gloves
◦ consult microbiologist or infection control nurse for advice infection control manual for isolation protocols
contains advice on meningitis, D&V, open TB, MRSA, hepatitis, HIV, and lots more besides - everything from Lassa to lice!!
Prophylaxis◦ e.g. of contacts of chickenpox, diphtheria, meningitis
•
•
Risks from Hospital StaffRisks from Hospital Staff
Take Care Of Yourself!◦ Your first responsibility is to your patients not your
colleagues Do not work if you have diarrhoea, or a flu-like illness, a sore
throat, or if you may be incubating a viral illness such as measles, rubella, chickenpox!
Be Considerate To Lab Staff!◦ Don't send specimens to the lab without proper packing,
leaking and / or blood-stained specimens are not acceptable!!!
◦ Label hazardous specimens
SummarySummary Sources of infection Transmission of Infection Patterns of Infection Outbreaks & Epidemiological typing Infection Control
◦ General Principles: Hospital & Community◦ Who’s who
Hospital-acquired infection◦ Syndromes◦ Rogues’ gallery◦ Control of Cross-Infection◦ Risks from Hospital Staff
...and some final words on ...and some final words on Hospital Infection Control...Hospital Infection Control... An extract from the
work book of Dr Fester, aged 24 and a half, newly qualified house officer...
50 lines as punishment for poor hand hygiene
I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients I promise to wash my hands between patients...
file:///C:/Users/User/Documents/authorGEN%20Projects/3.%20prevention1_infcontrol/aP%20Lite%20Flash/index.html
Thanks