Nosocomial Infections Epidemiology and key concepts. Nelly Hassan Ali ElDin Department of Cancer Epidemiology & Biostatistics. It is an infection acquired in a medical setting in the course of medical treatment. It meets the following criteria: 1 - Not found on admission
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Nosocomial Infections Epidemiology and key concepts
Nelly Hassan Ali ElDin
Cancer Epidemiology & Biostatistics
It is an infection acquired in a medical setting in the course of medical treatment. It meets the following criteria:
1 - Not found on admission
2 – Temporally associated with admission or a procedure at a health-care facility
3 – Was incubating at admission but related to a previous procedure or admission to same or other health-care facility.
It is an important public health problem because of their frequency, attributable morbidity and mortality and cost. In the USA and in Europe, approximately 5–10% of hospitalized patients develop an infection during their hospital stay. Higher incidence rates are reported in hospitals in developing countries.
In our hospital (National cancer Institute,), blood stream infections among pediatric patients accounted for 87.6/1000 discharges at 1999).Hospital acquired infection HAI contributed to 37.5% of these episodes.
Monthly incidence of febrile episodes and associated BSI rates per 1000 discharges in the pediatric inpatient units from January to December 1999
Increased morbidity (serious consequences and permanent disability )
The length of hospital stay is prolonged, on average by 5–10 days.
The risk of death approximately doubles in patients who acquire hospital infection.
Hospital-acquired infections are very expensive and contribute significantly to the escalating costs of health care. It has been argued that, even if moderately effective, a hospital infection control program is one of the most cost-effective and cost-beneficial preventative medical interventions currently available.
The use of uniform definition is crucial if data from one hospital are to be compared with those of another hospital (inter-hospital) or with an aggregated database (intra-hospital).
NI is a localized or systemic condition:
1- that results from adverse reaction to the presence of an infectiuos agent(s) or its toxins and
2- that was not present or incubating at the time of admission to the hospital.
For most bacterial NI, it become evident 48 hours or more (typical incubation period) after admission. Because the incubation period varies with type of pathogen, and extent of the underlying condition, each infection should be assessed individually for evidence that links it to hospitalization.
In superficial incisional surgical site infections (SSI) which involve only the skin or subcutaneuos tissues, it occurs within 30days after the operation.
In deep incisional SSI which involves deep soft tissues (fascia and muscles) and organ/space SSI which involves anatomic structures not opened or manipulated during operation, in both conditions; it occurs 30days of operation or within one year if an implant is present.
First (available information):
The information used to determine the presence and classification of an infection should be a combination of clinical findings, laboratory evidence and supportive data.
Clinical evidence is derived from direct observation of the infection site or review of other pertinent sources of data such as the patient’s chart or medical record.
Laboratory evidence includes results of cultures, antigens or antibody detection or microscopic examination.
Supportive data are derived from other diagnostic studies such as: X-ray, US, CT, MRI, BAL, Endoscopy, ..etc
Second, (a physician’s or surgeon’s diagnosis)
The diagnosis of infection by the surgeon or physician is derived from direct observation during a surgical operation, endoscopic examination or other diagnostic study or from clinical judgment. This diagnosis could be an acceptable criterion for an infection unless there is compelling evidence to the contrary.
For certain sites of infections, however, a physician’s clinical diagnosis in the absence of supportive data must be accompanied by initiation of appropriate or empirical antimicrobial therapy to satisfy the criterion.
There are two special situations in which an infection is considered nosocomial:
a) Infection that is aquired in the hospital but does not become evident until after hospital discharge.
b) Infection in a neonate that results from passage through the birth canal.
There are two special situations in which an infection is not considered nosocomial:
Infection that is associated with a complication or extension of infection already present on admission, unless a change in pathogen or symptoms strongly suggests the acquisition of new infection.
In an infant, an infection that is known or proved to have been acquired transpalcentally (e.g congenital rubella, toxoplasmosis) and become evident at or before 48 hours after birth
1) Colonization, which is the presence of microorganisms (on skin, mucous membranes, in open wounds or in execretions or secretions) that are not causing clinical signs or symptoms. .
2) Inflammation, which is a condition that results from tissue response to injury or stimulation by noninfectious agnets such as chemicals.
There are two additional points that are important to understand regarding the definition of NI:
Fisrt) the preventability of an infection is not a consideration when determining whether it is nosocomial.
For example, preventing the development of nosocomial C. difficle pseudomembraneous colitis after extensive antibiotic treatment may not be possible (i.e inevitable in some immunocompromised patients)
Another example some would argue that neonatal infections acquired during vaginal delivery are inevitable and, therefore, should not be counted as nosocomial.
However, these neonatal infections are nosocomial, they can be identified as maternally acquired, and the analysis of their incidence can be dissiminated to obestetricians for interventional strategies (i.e preventable).
Second), surveillance definitions are not intended to define clinical disease for the purpose of making therapeutic decisions. Some true infections (HIV infection) will, therefore, be missed while other conditions (asymptomatic bacteruria) may erroneously be counted as infections.
There are three principal goals for hospital infection control and prevention programs:
Protect the patients
Protect the health care workers, visitors, and others in the healthcare environment.
Accomplish the previous two goals in a cost effective and cost efficient manner, whenever possible.
The provision of an effective infection control program (ICP) is a key to the quality and a reflection of the overall standard of care provided by the health care institution.
Major differences among countries in their health care resources and organization, and medical cultures explain the diversity of approaches to the organization of hospital hygiene and infection control programs.
The growth in ICP has been paralleled by the establishment and growth of a number of professional and governmental organizations which focus on NI prevention and control such as (APIC, SHEA, CDC, HICPAC).
In the majority of countries ICP, typically operates on two levels: an executive body – the infection control team(ICT)– and an advisory body to the hospital management – the infection control committee(ICC)– which adopts the ‘legislative’ role of policy making.
The hospital ICC is charged with the responsibility for the planning, evaluation of evidenced-based practice and implementation, prioritization and resource allocation of all matters relating to infection control.
The ICC must have a reporting relationship directly to either administration or the medical staff to promote ICP visibility and effectiveness. The ICC should meet regularly (monthly) according to local need
The membership of the hospital ICC should reflect the spectrum of clinical services and administrative arrangements of the health care facility. As a minimum, the committee should include:
It comprises the infection control doctor ICD and infection control nurse ICN. The ICT is responsible for the day-to-day running of ICPs. It is important that all hospitals should have an ICT. The optimal structure of ICT will vary with needs and resources of the facility. The ICT must have the authority to manage an effective ICP. In large hospitals, this usually means a direct reporting relationship with senior administration
The role of ICT is to:
Ensure that an effective ICP has been planned, co-ordinate its implementation, and evaluate the impact of such measures.
It is important to ensure that there is a 24-hour access to the ICT for advice on infection prevention and control which would include both medical and nursing advice.
The infection control physician should be a medically qualified senior staff of the facility who is interested in and who spends the majority of his time involved in hospital infection control.
He could be a medical microbiologist, an epidemiologist or infectious disease physician
Irrespective of his professional background, the ICD should have the interest, knowledge and experience in different aspects of infection control.
An ICN or practitioner is a registered nurse with an additional academic education and practical training which enables her to act as a specialist advisor in all aspects relating to infection control.
The ICN is usually the only full-time practitioner in the ICT and therefore takes the key role in day-to-day infection control activities with the ICD providing the leading role
The role and responsibilities of the ICN are summarized as follows:
Infection control is a quality management function
Quality is defined by its attributes: effectiveness, efficiency, optimality, acceptability, legitimacy, and equity. Quality is also the relationship of structure, process and outcome.
Quality is “hassle elimination”
Quality is the result of planning, monitoring (through measurement) and improvement (through team effort)..
Improvements in quality are achieved by understanding processes, and variations and are supported by teamwork and scientific approach