بسم اللة الرحمن الرحيم. Nosocomial Infection and Infection Control By Prof. Dr. Mohamed I. Bassyouni

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


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”


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!


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


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