HOSPITAL ACQUIRED

INFECTIONSDr Khushdeep

Dr Imtiaz

Introduction & EtiologyHospital infection control

Introduction & Etiology• Definition• Criteria for hospital Acquired Infections• Impact on Economy & Health state• Factors affecting development HAIs• Sources of Infection• Modes of Infection• HAIs at different body sites• At extremes of age

• Hospitals bring together vulnerable hosts• Subject them to particular risks of

infection• Cause of morbidity and mortality• Limits effectiveness, adds greatly to cost

Hospital-acquired infection (HAI)

( nosocomial infection)• An infection acquired in hospital by a patient who

was admitted for a reason other than that infection .

or• An infection occurring in a patient in a hospital or

other health care facility in whom the infection was not present or incubating at the time of admission. This includes infections acquired in the hospital but appearing after discharge, and also occupational infections among staff of the facility

• ‘healthcare-associated infection’

Impact of HAI• Add to functional disability and emotional

stress• May lead to disabling conditions that reduce

the quality of life• One of the leading causes of death • Add to the imbalance between resource

allocation

• Significant cause of increased morbidity and mortality in hospitalized patients

• 80% of all hospital deaths are directly orindirectly related to HAIs (Hughes et al., 2005)

• Prevalence varies from 3.8% to 18.6% depending on the population surveyed and the definitions used (Jensen, 2008)

• Economic burden

Factors influencing development of HAI

• The microbial agent - resistance to antimicrobial agents - intrinsic virulence - amount of infective material.• Patient susceptibility - age - immune status - underlying disease - diagnostic and therapeutic interventions - extremes of life

• Environmental factors - Crowded conditions within the hospital - frequent transfers of patients from

one unit to another - concentration of patients highly

susceptible to infection in one area• Bacterial resistance - Through selection and exchange of

genetic resistance elements, antibiotics promote the emergence of multidrug resistant strains of bacteria

Source of the infecting organism

• Can be: - exogenous (equipment) - another patient ( cross infection ) - hospital staff - hospital environment - endogenous

Modes of Spread of Infection

1. By Contact:• Staff• Environment (including operation

theatre)• Equipment (including blood products)2. Air borne3. Water borne4. Food borne

1. Infection by contactFrom staff:• Resident (persistent over time and not readily

removed by hand washing)• Transient (recently acquired from another source)• Important microorganisms are - S. aureus - Klebsiella spp. - Serratia spp.

• Other less common organisms are - antibiotic resistant enterococci - C. difficile - Corynebacterium diphtheriae - candida albicans - RSV - Rhinoviruses

From the patient’s environment

• Becomes contaminated with bacteria carried by a patient

• Includes - VRE - MRSA - A. baumanii - P. aeruginosa - C. difficile

Infection in operating theater

• Most infections arise from the patient’s own flora

• The remainder are acquired mainly from staff in OT

• Ultraclean air – very low rates of clinical infection

• But - increased operative skills - prophylactic use of antibiotics may have played a part

From equipmentPatients with impaired immunity• Adhesive plaster contaminated with - Rizopus• Unsterile wooden tongue depressors- Rizopus• Bedpans and urinals - C. difficile - antibiotic resistant GNB• Rectal thermometers - salmonellae - enterococci

• Fiberoptic endoscopes - Salmonella spp. - P. aeruginosa - M. tuberculosis - H. pylori - hepatitis B ( rarely ) - HIV not been reported

Infection by inoculation• Infrequent in developed world - introduction of single-use disposable needles - satisfactory sterilization of surgical instruments• The prions – highly resistant• Risk of infections still persist in situations like: - transmitted by blood transfusion or tissue donation - accidental injury from contaminated sharp

instruments - contaminated blood - contaminated infusion fluids

Blood transfusion and tissue donation

• Risk of transmission of 3 most important agents - hepatitis B, C and HIV has been reduced• Other less common infections - Hepatitis D & G - syphilis - Cytomegalovirus - salmonellosis - Epstein-Barr virus - malaria - Parvovirus - trypanosomiasis - HTLV-1 - toxoplasmosis - Brucellosis - babesiosis - filariasis

Infection from accidental inoculation

• Tuberculosis of skin ( prosector’s wart )• Hepatitis B• Hepatitis C• HIV

Infection from contaminated infusion

fluid• TPN fluids such as protein hydrolysate with

or without dextrose, readily support the growth of organisms , particularly

- Klebsiella - Enterobacter - Candida spp.

Ventilator-associated pneumonia

• Mortality rate : 6-14%• Risk factors include - events that increase colonization by

potential pathogens - those that facilitate aspiration of

oropharyngeal contents into the lower respiratory tract

- those that reduce host defence mechanisms in the lung and permit overgrowth of aspirated pathogens

Infection associated with indwelling medical devices

• The predominating bacteria are - CoNS, particularly S. epidermidis - S. aureus - Corynebacteria - Propionibacteria - Streptococci - Yeasts and filamentous fungi

Intravascular cannulae • Plastic cannulae vs. steel needles• May remain silent• Simple fever, septicemia or disseminated

infection• Rate of colonization depends on - site ( LL>UL) - fluid infused ( TPN ) - design of cannula - plastic used - aseptic precautions at insertion

Intravascular grafts:• Cardiac valve prosthesis• Patches of polymers• Grafts in vessels

Joint prosthesis:• A very serious and costly complication• Incidence has reduced to <2%• - prophylactic antibiotics• - ultraclean air• - incorporation of antibiotic in bone cement• Spectrum of organisms include - S. aureus - CoNS - Enterobacteria - Streptococci ( mainly enterococci ) - Fungal infection - rare

Cerebrospinal fluid shunts:• Infection may give rise to - systemic illness from bacteremia - ventriculitis - shunt blockage• S. epidermidis – most common infecting

agent

2. Air-borne spread• Effectiveness of this route depends on - number of microorganisms present - degree of dispersal - survival and retention of pathogenicity by

the microorganism in the air or environment - size of the infecting dose - local and general susceptibility of the

persons exposed • Bacteria, Virus, Fungus : all are culprits

Tuberculosis • Air borne spread can occur by transfer of

Very few microorganisms• Patients differ in ability to transmit TB• Only patients with smear positive pulmonary

tuberculosis are regarded as constituting an infection risk and require single room isolation

• Infectivity declines rapidly after effective treatment

• MDR TB in HIV patients

Pneumococcal infection• Most infection by S pneumoniae is

endogenous• Not customary to isolate patients • Diagnosed by Gram stain of sputum-

advisable to isolate patients for the first 24 h of treatment

• Protection of vulnerable patients with polyvalent vaccine becomes more important as resistance increases

Meningococcal infection• Uncommon• Isolation for first 48 h of treatment is advisable• Among staff, only those who have had close

contact with the patient need to be offered prophylactic antibiotics

Other bacteria:• S aureus• S pyogenes• P aeruginosa

Viral infection• Chicken pox• Measles• Influenza• Respiratory syncitial virus (RSV)• Small round structured viruses (SRSV) -

noroviruses

Fungal infection• Dispersal by spores – most filamentous

fungi• Only Aspergillus spp. have been shown to

be a significant cause of air borne infection - after cardiac surgery - in immunosuppressed patients• Phycomycetes – occasionally• Cryptococcus neoformans – no convincing

evidence

3. Infections associated with water

Legionnaires’ disease • The legionellaceae are widespread in water• Legionella pneumophila ( particularly serotype

1)• Water in equipment that delivers nebulized

spray• Hot water systems• Air cooling towers• Source of infection – environmental water• Person to person spread is unknown

Other bacteria:• Aeromonas hydrophila – pneumonia• Pseudomonas spp.• Burkholderia cepacia

4. Infection acquired from food

• Salmonella infections- poultry, eggs• Clostridium perfringens – meat• Can be a source of antibiotic-resistant

bacteria - P. aeruginosa - Escherichia coli - Klebsiella spp.

• Catering faults most often responsible: - failure of staff to follow good practice - incomplete defrosting of frozen meats

and poultry - insufficient cooking of large amounts of

food - use of raw or insufficiently cooked egg

products - inadequate chilling and storage

Hospital Infections at various body sites

Urinary tract• 40-45% of nosocomial infections• Associated with - urethral catheterization - cystoscopy - transurethral prostatectomy• Route of infection is between the catheter

and the urethral wall

• Early infection is by local commensals - E. coli - CoNS - Enterococci• Later more resistant hospital associated GNB - Klebsiella - Proteus - Serratia - Pseudomonas may invade• Benign and symptomless in many patients• Some develop pyelonephritis, epididymoorchitis

Eye • Cornea is considered sterile• But conjunctiva is colonized - CoNS - Corynebacterium spp. - Propionibacterium spp.• Use of contact lenses, postoperative

infection

• Infection after cataract surgery has declined• Endophthalmitis- following surgery,

penetrating trauma• Keratoconjunctivitis caused by P.

aeruginosa• Epidemics caused by adenovirus type 8 –

speed by instruments, hands of staff• Hospital acquired bacterial conjunctivitis -in

neonatal units

GIT• Gastroenteritis:• most common nosocomial infection in

children - Rotavirus• Clostridium difficile - major cause in adults

Peritoneum • Peritonitis is one of the classical association

of surgery• Peritoneal dialysis is often complicated by

peritoneal infection by GNB• CAPD peritonitis has different spectrum of

etiologic agents and CoNS ( S. epidermidis ) account for about half the cases

• Patient motivation, good surgical technique, occlusive dressing

Nosocomial pneumonia• 15–20% of nosocomial infections • Almost all cases are caused by aspiration

of endogenous or hospital-acquired oropharyngeal (and occasionally gastric) flora

• associated with more deaths than infections at any other body site.

• Early-onset nosocomial pneumonia (within the first 4 days of hospitalization)

- Streptococcus pneumoniae - Haemophilus species• Late-onset pneumonias - S. aureus - P. aeruginosa - Enterobacter species - Klebsiella pneumoniae - Acinetobacter

Surgical site infections…• 0.5-15% of HAI• A cause of morbidity, prolonged hospital

stay• S.aureus ( MRSA )- dominating species

SSI…Predisposing factors - age over 60 years - long post operative stay - pre-existing infection at the site of the wound - underlying diseases-DM, immunosuppression,

irradiation, malnutritioninfection is usually acquired during the operation

itself; - either exogenously (e.g. from the air,

medical equipment, surgeons and other staff) - endogenously from the flora on the skin or in

the operative site ( predominantly ) - rarely, from blood used in surgery

…SSI• The main risk factors are - Extent of contamination during the

procedure (clean, clean-contaminated, contaminated, dirty)

- Presence of foreign bodies including drains - Virulence of the microorganisms, - Concomitant infection at other sites - Use of preoperative shaving - Experience of the surgical team

Burns • A suitable site for bacterial multiplication• S. aureus and P. aeruginosa -most common

isolates• Enterobacteria• Other gram negative bacilli such as acinetobacter• Bacteria reach burns mainly by indirect contact• Colonization without invasion is far more common

than invasive infection• Air borne infection is more important for S.

aureus than for GNB

Hospital Infections at extremes of life

How are these different…?

• Immunocompromised states• Hospital infection and infection control is

often neglected - Declining defenses - Multiple underlying chronic diseases - Long stay at hospitals• CAUTION: - Proteus , Providencia spp. - tuberculosis, influenza A virus - Salmonella infection - CDAD

Neonatal units• Underdeveloped defenses, lack of normal

flora (particularly in premature babies )• Ill babies require much handling by staff• CAUTION:

- MRSA - Klebsiella - P. aeruginosa - Serratia - S. epidermidis

Hospital acquired infections

Management and control

HAI control• Although eradication of HAI is impossible, a well-conducted

surveillance and prevention program may significantly reduce HAI and associated costs

• Identification of high risk population

• Identification of diseases at an early stage

• Treatment

• Environment

• Periodic surveillance

Surveillance

• Systematic observation and recording of diseases• An active ongoing process• Results can be used as an indicator of quality of

care

• Prospective surveillance is costly; therefore, point prevalence surveys point prevalence surveys are preferred for determining the magnitude of HAIs in countries with limited resources

Guidelines

• Identifying patients at risk• Observing hand hygiene• Standard precautions to reduce transmission

of infection• Strategies to reduce VAP, CR BSI, CAUTI• Designated infection control team(s)

*VAP: ventilator associated pneumonia*CRBSI: catheter related blood stream infection*CAUTI: catheter associated urinary tract infection

Identifying patient at risk

• Burns patients• Immunodeficient patients• Transplant recipients• Chronically debilitated patients• Major surgery• Ventilator support• Indwelling catheters• Prolonged ICU stay (>3 days)• Old age• Frequent blood transfusion

Isolation

• Keep the patient away from potential sources of infection

• Assess the need for isolation– Neutropenia and immunological disorder – Burns– Diarrhea– Skin rashes– Known communicable disease– Carriers of an epidemic strain of bacterium

• Identify the type of isolation– Protective isolation– Source isolation

• Isolation rooms should have:– Tight­f itting doors– Glass partitions for observation – Negative pressure (for source isolation) ventilation– Positive pressure (for protective isolation)

ventilation

Hand hygiene• Hands are the most common vehicle for

transmission of organisms

• Single most effective means of preventing the horizontal transmission of infections amonghospital patients and health care personnel

Hand hygiene

• During surgical hand preparation, all hand jewelries (e.g. rings, watches and bracelets) must be removed

• Finger nails should be trimmed

Standard precautions

• All cases• Gloves• Gown• Mask, eye protection/face shield• Shoe and head coverings• Patient care equipments• Avoid wearing long sleeves• House coats are discouraged and

wearing scrubs is encouraged

Transmission based precautions

• Patients known or suspected to have airborne, contact or droplet infections:

1. Isolate with negative pressure ventilation2. Respiratory protection3. Disposable N 95 respirator mask4. Limit transport of the patient

Specific strategies - specific nosocomial infections

1. Strategies to reduce VAP2. Strategies to reduce CRBSI3. Strategies to reduce UTI

Strategies to reduce UTI

• Catheters only for appropriate indications

• Closed drainage system• Unobstructed urine flow• Changing indwelling

catheters at fixed intervals is not recommended

• Remove the catheter when it is no longer needed

Strategies to reduce VAP• Avoid intubation whenever possible • Prefer oral intubations to nasal • Keep head elevated at 30° - 45° in the semi -

recumbent position• Daily oral care with chlorhexidine solution• Sedation-vacationSedation-vacation and readiness to intubate• Routine change of ventilator circuits is not

required• Prefer endotracheal tubes with a subglottic

suction port• Closed endotracheal suction systems are

better• Periodically drain and discard any

condensate

Strategies to reduce CRBSI

• Avoid femoral route for central venous cannulation, prefer upper extrimity

• Maximal sterile barrier precautions, and a sterile full-body drape while inserting CVCs

• Clean skin usually with 2% chlorhexidine with 70% ethanol

• Chlorhexidine/silver sulfadiazine or minocycline / rifampin- impregnated CVCs

• Ultrasound guided insertion• 2% chlorhexidine wash daily for skin cleansing

Environmental factors

1. Cleaning and disinfection2. Architecture and layout3. Organizational and administrative measures

Cleaning and disinfection

• Some pathogens can survive for long periods in the environment, particularly MRSA, VRE, Acinetobacter species

• High quality cleaning and disinfection of all patient care areas, bedrails, bedside tables, doorknobs and equipment

• Disinfectants or detergents that best meet the overall needs of the ICU should be used for routine cleaning and disinfection

• Surface cleaning (walls) twice weekly, floor cleaning 2 -3 times/day and terminal cleaning (patient bed area) after discharge or death

Architecture and layout

• Situated close to the operating theater and emergency department for easy accessibility, but should be away from the main ward areas

• Central air conditioning systems with appropriate filters, air should be filtered to 99% efficiency down to 5 μm5 μm

• Minimum of six total air changes per room per hour, with two air changes per hour composed of outside air

• Isolation facility should be with both negative and positive pressure ventilations

• Adequate space around beds is ideally 2.5- 3 m• Adequate number of washbasins with alcohol gel dispensers

Organisational and administrative measures

• Better patient to nurse ratio in the ICU• Controlling traffic flow to and from the unit to reduce

sources of contamination• Waste and sharp disposal policy• Education and training for ICU staff• ICU protocols and SOPs• Audit and surveillance of infections and infection control

practices• Infection control team (multidisciplinary approach)• Antibiotic stewardship• Vaccination of health care personnel

Infection Prevention in Burns Patients

• Burn wounds can provide optimal conditions for colonization, infection and transmission of pathogens

• Source of infection: staphylococcistaphylococci located deep within sweat glands and hair follicles

• Routine surveillance cultures: – Early identification of organisms– Monitor the effectiveness of current wound

treatment– Guide an appropriate antibiotic therapy– Weekly

• Stringent isolation guidelines• Antibiotic prophylaxis: role of topical antimicrobials > systemic

antibiotics

• Early enteral feeding: increases circulation to the bowel, thereby decreasing ischemia post injury and the translocation of bowel flora

• Human tetanus immunoglobulin (250 -500 IU)

Immuno-compromised andTransplant Patients

• Greatest risk of infection caused by airborne or waterborne microorganisms

• Neutropenic for prolonged periods (ANC < 500 cell/cumm)

• Opportunistic infectionsOpportunistic infections– Exogenous acquisition of a particularly virulent

pathogen, e.g. meningococcal meningitis or pneumococcal pneumonia

– Reactivation of an endogenous latent organism, eg, herpes zoster virus, Mycobacterium tuberculosis

– Endogenous invasion of a normally commensal or saprophytic organism

Post transplant period

1. During the first month after transplantation:– >95% of the infections are due to bacterial or candida

infection of the surgical wound, vascular access, endotracheal tube, or drainage catheters

2. During the period 1 -6 months after transplantation:1.Two classes of infection : Infections caused by

immunomodulatory viruses and infections caused by opportunistic pathogens such as Pneumocystis carinii, Listeria monocytogenes and Aspergillus species

• In the late period: 1.Cryptococcus neoformans, P. carinii and L.

monocytogenes

Monitoring of Infection Control

Antimicrobial Stewardship

• Multidisciplinary antimicrobial stewardship program • Antibiotic stewardship refers to a set of coordinated strategies

to improve the use of antimicrobial medications with the goal of enhancing patient health outcomes, reducing resistance to antibiotics, and decreasing unnecessary costs

• Infectious disease physician and a clinical pharmacist with infectious disease training

• Clinical microbiologist, an information system specialist, aninfection control professional and hospital epidemiologist

• Close collaboration between the antimicrobial stewardship team, microbiology lab, hospital pharmacy and infection control team

Goal• Reduce inappropriate use of antibiotics; use of appropriate

antibiotics based on C&S reports• Antimicrobial cycling to decrease antibiotic resistance (? use)• Routine use of combination therapy• Optimizing antibiotic dose taking into consideration pk/pd

characteristic• Early switch from parenteral to oral antibiotics• Decreasing duration of antibiotic use as per clinical guideline• Optimal use of microbiology lab is an essential ingredient of

any stewardship program

Conclusion • Nosocomial infections are widespread. They are important

contributors to morbidity and mortality

• They will become even more important as a public health problem with increasing economic and human impact because of:

- Increasing numbers and crowding of people - New microorganisms - Increasing bacterial resistance to antibiotics

• Prevention is better than control

Thank you

References• Guidelines for prevention of hospital acquired infections Yatin Mehta,

Abhinav Gupta, Subhash Todi, SN Myatra, D. P. Samaddar, Vijaya Patil, Pradip Kumar Bhattacharya, and Suresh Ramasubban; Indian J Crit Care Med. 2014 Mar; 18(3): 149–163.

• WHO guidelines on hand hygiene in health care: A summary. 2014. Mar 10• Maselli DJ, Restrepo MI. Strategies in the prevention of ventilator associated

pneumonia. Ther Adv Respir Dis. 2011;5:131–41. [PubMed: 21300737]• Guidelines for the prevention of intravascular catheter related infections;

http://www.cdc.gov/hicpac/pdf/guidelines/bsi guidelines 2011.pdf• Guidelines for prevention of catheter associated urinary tract infections;

http://www.cdc.gov/hicpac/pdf/CAUTI/CAUTIguideline2009final.pdf .• Malhotra S, Sharma S, Hans C; Prevalence of Hospital Acquired Infections in

a tertiary care hospital in India; Department of Microbiology, PGIMER and Dr RML Hospital New Delhi; International Invention Journal of Medicine and Medical Sciences (ISSN: 2408-7246) Vol. 1(7) pp. 91-94, July, 2014