HOSPITAL ACQUIRED INFECTIONSRosemary MwifiGiven Sishekano

OUTLINE Introduction Epidemiology Risk factors Microbiology of commonly implicated organisms Infection prevention and control measures Reducing Antimicrobial resistance Quiz References

INTRODUCTION Hospital acquired infections (HAI) are also known as nosocomial infections.• The word is derived from the Greek word nosokomeon meaning hospital. • Nosos = disease and • komeo=to take care of.

They are infections acquired by: patients in the hospital while they are receiving treatment for other conditions

or health workers in the health setting as they perform their duties.

HAI appear 48 hours or more after hospital admission, in a previously uninfected patient. Time is however relative depending on the infection.

EPIDEMIOLOGY A prevalence study conducted under WHO in 55hospitals of 14 countries in Europe, Eastern Mediterranean, South-east Asia and Western pacific showed an average of 8.7% hospital patients had nosocomial infections.

In South Africa, studies reflect an infection rate of nosocomial of 15% and an associated attributable mortality rate of 5%.

Nosocomial infections occur about 25% more in hospital patients in developing countries than in developed countries.

Developed countries are less likely to have more surgical wound/trauma due to less invasive surgical practices. They however experience more UTI’s.

RISK FACTORS (PATIENTS) Some patients present with risk factors upon arrival. Patients are at risk when they are at extremes of age due to poor immune defenses (very young or very old).

Patients with underlying chronic conditions that compromise their immune system; such as HIV, cancer, diabetes and renal failure.

Patients with trauma, or from road accidents may have cuts or burns are more susceptible as a result of skin breach.

Medication such as immunosuppressive, cytotoxic agents as well as steroids are known to put patients at risk of more infections.

RISK FACTORS (PATIENTS) While in hospital, more risk factors can arise. Skin may be breached after surgery or subsequent wound care . The use of indwelling devices such as urinary catheters, endotracheal tubes and other monitoring devices may be a route for entry of bacteria.

Certain drug therapy may increase the risks. E.g. broad spectrum antimicrobial agents, or unnecessary use of antibiotics in addition to fighting infections also reduce normal flora and leave the patient exposed to other infections.

Blood transfusions or parenteral therapy. Hospital staff infected with transmissible illnesses. The use of sharps such as needles, and IV devices.

RISK FACTORS (HEALTH CARE STAFF) The hands of health care workers are the highest risk factor especially in the absence of gloves when carrying out patient care duties.

White coats and other uniform. Student lab coats especially using the same coat for dissection, lab work and hospital.

The use of sharps, such as needles and IV needles.

SOURCES AND TRANSMISSION OF HAI Can be endogenous or exogenous. Contact; Colonisation or infection with multi-resistant organisms MRSA, Methicillin

Resistant Staphylococcus Aureus), etc Enteric diseases eg Human Rotavirus, Hepatitis A, Clostridium difficile Respiratory diseases, eg SARS, Bronchiolitis/RSV (also refer to Droplet Precautions) Skin infections

Direct contact from the hands/body of health care staff. This is from caring from various patients, and coming into contact with bodily fluids, catheters, administering medication or manipulating IV sites. (especially the moist, warm area under the watch strap).

Indirect contact from an object such as linen, doors,ward telephones or trolley handles. Improper use of gloves where health workers wear gloves continuously, offer cross

infection. Needles not disposed off properly are hazardous and may transmit blood borne viruses

such as HIV and Hepatitis.

SOURCES AND TRANSMISSION OF HAI Skin (both direct and indirect contact) Individuals may shed a lot of skin. Those with eczema or psoriasis are particularly more prone to shed while their skins are heavily colonised with Staphylococci.

Vehicles of transmission Food-borne transmission of gastrointestinal pathogens is rare unless kitchen hygiene is compromised.

Waterborne transmission occurs more as a result of birthing pools, hydrotherapy pools, air conditions, endoscopy washers disinfectants. These may be associated with environmental mycobacteria, environmental Gram negative bacilli as well as Legionella species.

SOURCES AND TRANSMISSION OF HAI Iatrogenic Contaminated drugs for administration Blood for transfusion Environmental Overcrowding Cleaning practices that are not adequate, appropriate, regular or not using appropriate chemicals.

Sterilization of objects that is inadequate.

SOURCES AND TRANSMISSION OF HAI Droplets Large droplets are larger than 5micrometers in size and fall onto surfaces within a 1-metre radius. Generated by coughing, sneezing, talking or from procedures such as bronchoscopy or suctioning. They are propelled into the air and may land on nasal mucosa or conjuctival mucosa.

Nasal secretions may contaminate health workers hands if they are ill, contaminating everything they touch from then on.

These include Bronchiolitis, Meningococcal infections Viral infections including influenza, mumps and rubella Small droplets are less than 5micrometers in diameter and are responsible for airborne transmission. These pathogens such as chicken pox virus, respiratory virus and Mycobacterium tuberculosis remain suspended in the air for long periods of time.

Contact precautions• Contact Precautions are

undertaken to reduce the risk of transmission of pathogenic micro-organisms by direct or indirect contact. Contact transmission can occur from:

• Skin to skin contact• A contaminated piece of

equipment• The client’s environment• Examples of pathogens

transmitted by this mode include:

• Deleted this by accident, please re-add these organisms here?

Airborne precautions• Airborne Precautions are

taken to reduce the risk of transmission of pathogenic micro-organisms through airborne particles. Airborne particles are smaller than droplet (less than 5 um) and remain suspended in the air for long periods of time. They are transmitted when susceptible people inhale contaminated air.

• Examples of conditions transmitted by airborne particles include:

• Pulmonary Tuberculosis• Measles• Varicella• Severe Acute Respiratory

Syndrome (SARS).

Droplet infections• Unlike air borne particles

that remain suspended in the air for extended periods, droplets are larger than 5um in size and fall onto surfaces within a 1-metre radius.

• Examples of conditions transmitted through droplets include:

• Bronchiolitis• Meningococcal infections• Viral infections including

influenza, mumps and rubella.

Skin precautions• As per Contact

Precautions scabies can be transmitted from skin to skin or from contaminated client environment or equipment to susceptible people. Due to the copious amounts of skin shedding and large number of mites present on the client and their surrounding environment extra precautions are required.

• This category of precautions is exclusive to:

• Crusted (formally called Norwegian Scabies) scabies.

COMMON INFECTIONS/ILLNESSES Urinary tract Infections (80%)

Esterichia coli Ventilator associated Pneumonia (3%)

Acetinobacter, Kleibsella, Staphylococcus Surgical site infections (0.5 to 15%)

Pseudomonas, Coagulase negative Staphylococci

Bloodstream infections; Staphylococcus Gastroenteritis; Clostridium defficile

Rotavirus

MICROBIOLOGY OF COMMON ORGANISMS Methicillin Resistant Staphylococcus aureus Vancomycin resistant Enterococci ESBL producing organisms Legionella Viruses Fungi: Candida albicans, Aspergillus

S. AUREUS(MRSA) Methicillin Resistant S. aureus(MRSA)

One of the most important Nosocomial pathogens worldwide.

It is resistant to methicillin and other members of the penicillinase-resistant penicillins

This is because it possesses a penicillin-binding protein 2a that has reduced affinity for binding to beta-lactam agents.

This protein is encoded by the mec A gene, which is carried by a large mobile element referred to as staphylococcal chromosome cassette(SCC) mec.

These are occasionally sensitive only to Vancomycin and Teicoplan

Vancomycin Intermediate Resistant S. aureus(VISA)

Resistance may occur due to prolonged exposure to vancomycin, renal failure requiring dialysis, invasive intravascular devices, and prior infection with MRSA.

Resistance mechanism has yet to be clarified. Cell wall thickening has however been identified as a common feature of VISA. Experiments have shown that resistance may be caused by clogging of the thickened cell wall with vancomycin.

VISA remain susceptible to tetracyclines, Linezolid, Tigecycline and TMP/SMX

COAGULASE NEGATIVE STAPHYLOCOCCI. They are gram positive cocci, they mediate virulence by producing slime or glycocalyx to form a biofilm on intravascular catheters and prostheses.

Bacteria embedded in biofilm can cause serious systemic infections and are difficult to treat as most antibiotics are unable to penetrate or eradicate biofilms.

Multi-drug resistant strains are fast becoming major hospital pathogens.

Common resistance to quinolones, cephalosporins and vancomycin.

VANCOMYCIN RESISTANT ENTEROCOCCI(VRE) Enterococci are gram positive cocci, seen in pairs of short chains.

Forms part of the normal flora of the human intestines and female genital tract and are often found.

May cause infections, particularly in hospitalized and debilitated individuals.

Enterococci are intrinsically resistant to many antibiotics. In treatment, combinations of a cell wall active agent and an aminoglycoside is necessary for effective treatment.

Vancomycin or Teicoplanin is a glycopeptide that is often used to treat infections caused by enterococci.

VRES CONT… VREs are resistant to vancomycin, infections with VREs occur most commonly in hospitals.

This resistance is transferable, through mobile genetic elements carrying the van A(high level resistance) or van B(low level resistance) genes.

The potential mergence of vancomycin resistance in methicillin resistant staphylococcus or S. epidermis is a great threat.

GRAM NEGATIVE: ACINETOBACTOR, PSEUDOMONAS, ESBL PRODUCING ORGANISMS Acinebacter and pseudomonas are gram negative rods, commonly found

in soil and water. Acinebacter can also be found on skin of healthy people, especially

healthcare personnel. A. baumannii accounts for about 80% of all reported Acinebacter

infections. Infection with Pseudomonas and Acinebacter rarely occurs outside of

healthcare settings. Outbreaks typically occur in intensive care units and units that care for

seriously ill and debilitated individuals. These two are resistant to most commonly prescribed antibiotics. Decision on treatment should be made on a case-to-case basis after

culture and susceptibility results are available.

GRAM NEGATIVE: ACINETOBACTOR, PSEUDOMONAS, ESBL PRODUCING ORGANISMS CONT... Extended-spectrum beta-lactamases (ESBL) are enzymes that confer resistance to most beta-lactam antibiotics, including penicillins, cephalosporins, and the monobactam aztreonam. Infections with ESBL-producing organisms have been associated with poor outcomes.

Multi-drug resistant extended spectrum beta-lactamases are emerging as important nosocomial pathogens.

Klebsiella spp and more recently E. coli are the most commonly implicated organisms harbouring a variety of ESBL genotypes.

Several outbreaks of ESBL producing organisms has been reported worldwide.

Organisms producing ESBLs are able to hydrolyse the third generation cephalosporins

CONT… Through the production of different enzymes(TEM or SHV) coded for by different gene types.

More recently, CTX-M type ESBLs have been detected which preferentially hydrolises cefotaxime, although mutation can confer ceftazidime resistance activity.(these enzymes are sometimes referred to as cefotaximases.

The range of drugs used to treat ESBL producing organisms is restricted to the carbapenems.

CLOSTRIDIUM DEFFICILE It is a gram positive, rod shaped, sporeforming opportunistic pathogen.

Does not normally cause infection unless the normal intestinal flora is altered.

These alterations, most commonly due to antibiotic therapy, decrease the number of other colonising intestinal flora.

Most commonly associated antibiotics include; amoxicillin, cephalosporins, and clindamycin, though virtualy any antibiotic can be associated with C. defficile infection.

The severe diarrhoea and the lesions seen are due to and enterotoxin.

This enterotoxin has two components, toxin A which causes accumulation of fluid in the bowel lumen, toxin B which is cytotoxic and is thought to be primarily responsible for ulceration of the bowel wall.

LEGIONELLA PNEUMOPHILA Legionnaires' disease (LD) can be nosocomial, community acquired or

travel related. The source of Legionella infection is potable water systems that become

colonized by the microorganism (water heaters etc.). Prevention studies involved mainly hospital water systems. Different strategies have been suggested but none are fully successful:

engineering modifications, heating of water to temperatures above 59°C, heating and flushing the plumbing with hot water (80°C), water chlorination, silver-copper ionization of the water, UV-light disinfection of water, instant heating in order to avoid hot-water tanks and others.

It can cause two different forms of disease in humans: Legionnaire’s Disease, (incubation period: 2-10 days, multisystem illness that

involves the lungs, causing pneumonia, and can cause neurological symptoms, diarrhea and has a high mortality rate (up to 50%), and

Pontiac fever, with a shorter incubation period of 1-2 days, which is an acute, self-limited, influenza-like disease that does not cause pneumonia.

VIRUSES. Viruses have a long incubation period. Disease may not easily be linked to hospitalisation, unless if surveillance is conducted using epidemiological methods.

Viruses may cause both respiratory and GI disease including SARS and diarrhoea(commonly caused by Rotavirus in children)

Other diseases include measles, chicken pox etc. theses may require isolation of patients to avoid transmission to other patients.

Viruses such as Hep B and C, respiratory syncytial virus, CMG, HIV, HSV, VZV may be transmitted

FUNGI Aspergillus spp. Invasive aspergillosis has become a devastating opportunistic fungal infection among the immunocompromised hosts.

Commonly caused by Aspergillus fumigatus Can infect the lungs and other organs. Building dust is common source, hospital wards close to building sites should ensure the air is passed through special air handling units before admitting vulnerable patients.

Invasive aspergillosis commonly manifests as a lung infection and is almost always fatal

CANDIDA ALBICANS Candida albicans is an opportunistic fungal pathogen that is responsible for

candidiasis in human hosts. C. albicans grow in several different morphological forms, ranging from

unicellular budding yeast to true hyphae Typically, C. albicans live as harmless commensals in the gastrointestinal

and genitourinary tract and are found in over 70% of the population. Overgrowth of these organisms, however, will lead to disease, and it

usually occurs in immunocompromised individuals, such as HIV-infected victims, transplant recipients, chemotherapy patients, and low birth-weight babies.

INFECTION CONTROL MEASURES Measures practiced by health care personnel to prevent spread, transmission and acquisition of infection between clients, from health care providers to clients and from clients to health care providers.

Infection control measures are based on how an infectious agent is transmitted, they include:

The standard and Additional precautions.

STANDARD PRECAUTIONS Specific precautions designed to prevent harmful bacteria and viruses from infecting people who are providing first aid or health care.

They are a set of practices designed to prevent the transmission of HIV, Hepatitis B and other blood borne pathogens (bacteria and viruses).

Under SP, blood and other body fluids of all patients are considered potentially infectious.

STANDARD PRECAUTIONS Hand hygiene Personal protective equipment(PPE) Immunization Environmental sanitation Waste management Sharps management Decontamination

Hand hygiene• The most

important of the infection prevention and control strategies

• Cost-effective and practical measure to reduce the incidence of healthcare-associated infection and the spread of antimicrobial resistance across all settings. However,

PPEs• Specialized

clothing or equipment worn by an employee for protection against infectious materials

• These include:• Gloves• Aprons• Whitecoats• Gowns• Protective

eyewear• Face shields• Masks

Immunization• Immunization of

health care workers against infections like Hep B virus is one of the most importatant way infections are prevented from patients to Health care workers.

Waste + Sharps management

• Proper handling and disposal of needles.

• Taking precautions to prevent injury from scalpels, needles, and other sharp instruments.

• Place waste in a bag and tie it.

• Place in second bag and tie again (double bag technique)

• Place all sharps (used needles) in sharps container.

• Wash hands after removing gloves.

Decontamination

• Reprocessing of reusable medical equipment and instruments

• Keeping aseptic non-touch technique asceptic.

Environmental sanitation

• Routine environmental cleaning

ADDITIONAL PRECAUTIONS Additional Precautions refer to IPAC interventions (e.g., PPE, accommodation, additional environmental cleaning) to be used in addition to Routine Practices to protect staff and patients/residents by interrupting transmission of suspected or identified infectious agents. they are based on the mode of transmission (e.g., direct or indirect contact, airborne or droplet). There are three categories of Additional Precautions:

Contact Precautions Droplet Precautions Airborne Precautions

ANTI-MICROBIAL SUSCEPTIBILITY TESTING Two methods arused: 1. Disc diffusion method(Kirby-baur

test)

Commonly used agar: Mueller Hinton

agar

2. Broth dilution method

REDUCING ANTIMICROBIAL RESISTANCEReduce inappropriate use of antibiotics;Routine use of combination therapyOptimizing antibiotic dose taking into consideration pk/pd characteristicOptimal use of microbiology lab is an essential ingredient of any stewardship programIsolation of patients with antimicrobial resistance.Restrictive antibiotic use as below.Antimicrobial cycling to decrease antibiotic resistancePrescription follow up.

Antimicrobial Stewardship team

1. Leadership commitment:

Dedicate necessary

human, financial, and IT

resources

2. Accountability:

Appoint a single leader

responsible for program

outcomes. 3. Drug expertise:

Appoint a single pharmacist leader to support

improved prescribing.

4. Action: Take at least one prescribing

improvement action

5. Tracking: Monitor

prescribing and antibiotic resistance patterns.

CONCLUSION Nosocomial infections are widespread. They are important contributors to morbidity and mortality They are becoming even more important as a public health problem with increasing economic and human impact because of: Increasing numbers and overcrowding of people New microorganisms Increasing bacterial resistance to antibiotics

Prevention is better than control Antimicrobial resistance raises a new threat against humanity. Proper measures need to be put in place in order to win the war against anti microbial resistance.

QUIZ 1. _________ and _________ are the most common causes of infection in

hospitals A. Bacterial and fungal B. Staphylococci and E.coli C. Staphylococci and P.aeruginosa D. E.coli and P.aeroginosa

2. ______________ is the most commonly acquired hospital infection. A. Surgical wound infection B. Urinary tract infection C. Respiratory tract infection D. Infectious diarrhea

MCQ3. Standard precautions do not include:A. Washing handas before and after patient contactB. Appropriate handling of contaminated clinical wasteC. Use of asceptic techniqueD. Use of gloves and gowns at all times4. Which mode of transmission does not require the use of additional precautionsE. Airborne transmissionF. Bloodborne transmissionG. Droplet transmissionH. Contact transmission

REFERENCES Shetty, N. Tang,J.W. Andrews, J. (2009). Infectious diseases. Oxford, UK:

Blackwell publishing. Duse, A. (2005). Infection control in developing countries with particular

emphasis on South Africa. The Southern African journal of epidemiology and infection, Volume 20(2), 37-41.

Brink, A. Feldman, C. Duse, A. et al. (2006). Guideline for the management of nosocomial infections in South Africa . The Southern African journal of epidemiology and infection, Volume 21(4), 152-160.

WHO(2002). Prevention of hospital-acquired infections, a practical guide(2nd edition)

Yatin Mehta, Abhinav Gupta, Subhash Todi, SN Myatra, D. P. Samaddar, Vijaya Patil, Pradip Kumar Bhattacharya, and Suresh Ramasubban(2014). Guidelines for prevention of hospital acquired infections. Indian J Crit Care Med. 2014 Mar; 18(3): 149–163.