HOSPITAL CROSS-INFECTIONHOSPITAL CROSS-INFECTION

DefinitionDefinition

Cross-infection: infection that spreads from person to person.

Auto-infection : is derived from the patient himself.

Types of Infection in Types of Infection in HospitalsHospitals

Infection contracted & developing outside hospital & requiring admission to hospital

( pneumonia )

Infection contracted outside hospital & becoming clinically apparent in hospital

( measles )

Infection contracted & developing inside hospital (wound infection)

Infection contracted in hospital but becoming clinically apparent after discharge

( typhoid fever )

Endogenous InfectionsEndogenous Infections

• The infecting organism is derived from the patient (U.T.I. & pulmonary infections in recumbent patients )

• The bacteriological detection of such infections by blood culture is needed in major cardiac surgery or transplantation.

Exogenous infectionsExogenous infections

• Acquired from other patients or from staff carriers (nurses, doctors, medical students)

•The organisms causing such infections are usually highly infectious & very resistant to many drugs.

Mechanisms of transmission Mechanisms of transmission of exogenous infectionsof exogenous infections

• Direct contact with : fomites, contaminated instruments, etc.

• Air-borne dust & droplets.

• Contaminated food & eating utensils.

Surgical wound infectionsSurgical wound infections More frequent in emergency operations where infected tissue is likely .

Lowest in special surgical units (orthopedic & cardiac units) where elective surgery is done.

Surgical infections may Surgical infections may be:be:

• Endogenous: ( transfer of Staph.. or Strep.via patient nose, or coliform bacilli via bowel ) during operation.

• Exogenous, derived from other patients, healthy staff carriers, visitors, etc.

We differentiate between infection occurring during an operation or post-operatively by site & extent of infection & the time firstly recognized.

Surgical wound Surgical wound infections may be infections may be

divided into :divided into :

Infection contracted in theatre during operation.

Infection contracted in wards after operation.

Theatre Wound InfectionsTheatre Wound Infections

Apparent within 3 days following the operation.

It depends on : Virulence of infecting organism. Depth & size of wound. Duration of operation. Presence of drainage tubes. Normal flora of site. Patient age.

Late localized symptoms & signs, suggest a deep, seated abscess .

Sources of theatre infectionSources of theatre infection • Healthy staff carriers.• Unsterile textile• Unsterile instruments.• Air - borne theatre dust.• Faulty dressing technique.• Faulty theatre design.

Theatre Wounds :Theatre Wounds :Modes of TransmissionModes of Transmission

Surgeons hands through minute holes in gloves, or dripping of sweat on the wound.

An apparatus near the wound, e.g: operation lamps or portable x-ray machine.

Bacteria in laden particles of theatre air

Ward Wound InfectionWard Wound Infection

Appears from the 4th day after operation.

Predisposal factors are: Blood or serum seeping through

drainage tubes soaking dressings Lengthy procedures (evacuation a

blood clot formed in the ward ) Loose dressings Burns dressings

Cont.

Factors causing cross-infection Too frequent dressings. Insufficient facilities for

aseptic techniques. Shortage of staff ( delay in

dressings before rounds or visits)

Rapid inspection of wounds by surgeons without full re-dressing

Investigation of Hospital Wound Investigation of Hospital Wound InfectionsInfections

o Isolate & type the infecting organism.

o Determine whether it is a theatre or ward infection.

o Swab patient nose & throat to look for an endogenous infection.

o Swab noses of staff & patients to determine source of infection if organisms isolated are similar.

o If not similar it is a waste of time to search for carriers.

Organisms Causing Hospital Organisms Causing Hospital InfectionInfection

◊ Staph. aureus: *Commonest cause of wound infections.

*Phage typing determines the

strain causing infection. *Reservoir is the anterior nares,

transferred by direct & indirect contact.

Staph.Staph. infections are: infections are:

• Wound infections .• Boils,pemphigus neonatorum, carbuncles.

• Enterocolitis.• Pneumonia.• Breast abscess.• U.T.I.

◊ Strept. pyogenes: Reservoir is the throat, transferred by close direct contact ( will not survive long on skin)

◊ Gram negative intestinal bacilli: E.coli, Proteus vulgaris, Pseudomonas & Klebsiella.

*Cause wound infection by auto-infection.

*The anterior urethra is colonized by E.coli, Pr. vulgaris & E. fecalis.

Cont.

*Bacteria can be driven into bladder during catheterization ( cystitis )

*Urinary infection due to Pseudomonas is carried by hands of attendants from urine bottles to bladder drainage apparatus

*In other coliform wound infections the source of infection is septic wounds, e.g: fecal fistulae & colostomies.

◊ ClostridiaClostridia: @Reservoir is feces of man, animals , soil. @Harmless if anaerobic atmosphere is

unavailable. @It causes gas gangrene

@Factors predisposing to infections are:-* Faulty sterilization of dressings &

ligatures.* Excessive damage of tissue.* Sepsis of wounds by other

organisms.

Prevention & Control ofPrevention & Control ofHospital Cross-InfectionsHospital Cross-Infections

a)Asepsis measures: • Aseptic techniques.• Proper sterilization • Strict “No Touch” techniques.• Strict personal hygiene.• Health education ( patients, nurses,other staff ) • Use of disinfectants in localized

sites.

b) Isolation facilities: b) Isolation facilities: Cubicles & single-bedded rooms , needed for carriers & high-risk patients ( extensive skin grafting & burns patients )

c) Invasive procedures : c) Invasive procedures : Care should be taken with cannulation, catheterization, anaethetic machines, respirators etc.

d) Personneld) Personnel : *Staff with respiratory or surface infections should be prevented from nursing, treating or cutting patients.

*In theatre, surgical staff must be properly gowned, masked & capped.

*Thorough scrubbing & glove wearing should be a habit whenever touching a wound even in the ward .

*Auxulary staff , eg: catering and household-staff should be screened to detect carriers & give treatment .

e) Ward & theatre design : e) Ward & theatre design :

*Wards should be designed with adequate space & proper ventilation.

*Theatres should be separated from wards. *Accessory rooms should be separate.

*Ventilation should be monitored with a positive pressure system & air should be filtered.

f) Antibiotic policy : f) Antibiotic policy :

*Antibiotics must be used with care. *Abuse may lead to production of drug

resistance & multiplication of resistant organisms.

*The use of wide-spectrum antibiotics as a

pre-medication in bowel surgery is not important ; enema has got the same advantage.

*The use of prophylactic antibiotics must be stopped to avoid emergence of resistant bacteria.

Cont.

@Treatment of surgical wounds in theatre by irrigation , spraying & dusting has proved ineffective in preventing wound infections.

@Adoption of a rotational antibiotic policy using different sets of antibiotics for successive periods is the best way to control hospital infections & prevent drug resistance.

g) Staff conduct : g) Staff conduct :

• Careful cleansing & disinfection of operation site.

• Careful use of sterile materials & instruments.

• Gentle handling of tissues to avoid damage that may reduce their resistance to bacteria.

h)h) Record keeping:Record keeping:

To detect source of infection & to

point where preventive measures had been broken, we should record and register in details the:-

1. Nature of operation.2. Staff involved in theatre & ward.3. State of wound each time dressed.4. The site, nature & extent of any

infection arising in the wound.

i) Administration: i) Administration:

• The clinical bacteriologist

should supervise services in the ward & theatre.

• He must be included as a member in administration of concerned hospital units e.g.: theatre , pharmacy, wards, sterilization , etc.