|Year : 2018 | Volume
| Issue : 1 | Page : 14-21
Infection control in intensive care units
Department of Microbiology, Kasturba Medical College; Department of Infection Control and Management, Kasturba Hospital, Manipal, Karnataka, India
|Date of Web Publication||1-Feb-2018|
Dr. Chiranjay Mukhopadhyay
Department of Microbiology, Kasturba Medical College, Manipal - 576 104, Karnataka
Source of Support: None, Conflict of Interest: None
Infections acquired in the hospitals, especially in the intensive care unit (ICU) settings, ranging between 15% and 20%, may further lead to complications in >40% in critically ill patients. The order of incidence may vary in different settings, but the most usual causes are ventilator-associated pneumonia, intravascular catheter-associated bloodstream infection, catheter-associated urinary tract infection, posttraumatic intra-abdominal infection, and surgical site infection. These can be prevented by adequate and appropriate application of preventive strategies, which can be implemented strictly at the bedside. The basic norms for surveillance strategies, general preventive measures such as standard and isolation precautions and monitoring of antibiotic use should be followed without fail. Specific practical measures for ICU-related infections should be in place, and the monitoring of activities should be documented regularly as “bundle-care” in view of standardizing the practice, irrespective of place or person. Adequate attention, unfortunately, has not been paid for infection control measures in India for years. It is now mandatory that the essential practices are prioritized and integrated fully into regular hospital administrative procedure as a continuous process for improving quality health care.
Keywords: Handwashing, hospital-acquired infections, infection control, surveillance
|How to cite this article:|
Mukhopadhyay C. Infection control in intensive care units. Indian J Respir Care 2018;7:14-21
| Introduction|| |
Effective control of infection in the hospital, especially in the intensive care unit (ICU) set up, is always challenging; it not only demands adequate awareness and constant vigilance among the health-care workers (HCWs) but also needs a multidisciplinary approach to handle the management and control of infection in every patient. The WHO estimates that the rate of hospital-acquired infections (HAIs) is 7%–12% among hospitalized patients all over the world, where >1.4 million people had infection-related complications during their stay in the hospital at any time.,, The recent Centers for Disease Control report about HAI rates among National Acute Care Hospitals in USA (2014 data, published in 2016) informs us that there is a decrease in Central Line-Associated Bloodstream Infections (CLABSI) between 2008 and 2014, whereas no change was observed in overall Catheter-Associated Urinary Tract Infection between 2009 and 2014. It is also reported that there is 17% decrease in surgical site infection (SSI) related to 10 selected procedures, with special mention of 17% decrease in abdominal hysterectomy SSI, and 2% decrease in colon SSI in 6 years (2008–2014). The rate of hospital-onset Clostridium difficile infection has come down by 8% and hospital-associated methicillin-resistant Staphylococcus aureus (MRSA) bacteremia by 13% between 2011 and 2014. In 2011, there were an estimated 722,000 HAIs in USA acute care hospitals, out of which, about 75,000 patients died with HAIs occurred outside the ICUs. It has been predicted that appropriate steps to control and prevent HAIs in a variety of settings, by creating awareness among individual doctors and nurses may decrease some targeted HAIs (e.g., CLABSI) by >70%.
The burden of HAIs is more in the developing countries, with highest prevalence in the ICUs. A prospective, multicentric, and cohort surveillance study of device-associated infection as conducted by International Nosocomial Infection Control Consortium (INICC) in 55 ICUs of 8 developing countries including India revealed the overall rate of 14.7% HAIs corresponding to 22.5 infections/1000 ICU days. In 2007, the INICC conducted prospective surveillance from 12 ICUs in 7 different cities showed that the overall HAI incidence rate of 4.4% (9.06 infections per 1000 ICU days), where a total of 10,835 patients were studied for 52,518 days. Indian data on HAI during 2004–2012 showed that the HAI rates vary from 4.36% to 83.09% with infections per 1000 patient days ranging from 6.16 to 40.66. HAIs account for major causes of disability of the patient's functional aspects, economic burden, emotional suffering, and never the least, death among the hospitalized patients., The crude fatality rate in the INICC survey in India and other developing countries varies between 35.2% and 44.9%. The HAIs are mostly due to multidrug-resistant (MDR) hospital environmental flora, which demands the use of higher antibiotics for a longer duration. As a consequence, there is more chance of developing higher selection pressure and further development of resistance to reserved antibiotics, leading to increased length of stay for infected patients and increased chance of mortality. Moreover, use of higher-end antibiotics such as carbapenems, colistin, tigecycline, vancomycin, linezolid, and daptomycin to combat MDR HAIs increase the health-care cost immensely due to an increased need for isolation and the use of additional laboratory and diagnostic tools.
In the European Prevalence of Infection in Intensive Care Study, increased mortality rate is independently associated with laboratory-confirmed bloodstream infection, pneumonia, and clinical sepsis., However, other additional predictors of mortality such as APACHE (acute physiology and chronic health evaluation)–II score >20, prolonged (>21 days) ICU stay, age >60 years, the presence of organ failure or hospital admission, and cancer as comorbidity also play a significant role. The scoring systems (most widely used APACHE II/III) are more suitable to predict mortality, rather than predicting HAIs. On the other hand, understaffing and overcrowding in ICUs, type of nutrition (for example, catheter-related bloodstream infection (CRBSI) is apparently associated with total parenteral nutrition in critically ill patients), mechanical ventilation, length of stay, and ratio of nurse to patient were found to be major independent contributors for HAIs. Cross-transmission was facilitated by understaffing and overcrowding, along with carriage of Gram-negative fecal flora, leading to outbreak.,,,,,,
| Microbiology of Infections in Intensive Care Units|| |
As microbiology and pathophysiology of infections are common, there is a continuous shift toward more resistant strains over years, which includes MRSA, vancomycin-resistant enterococci (VRE), extended-spectrum beta-lactamases (ESBLs), carbapenems-resistant Enterobacteriaceae (CRE), colistin-resistant acinetobacter, and fluconazole-resistant Candida spp. These pathogens play a major role in HAIs, especially in ICUs, but the factors responsible for this evaluation are yet to be understood fully. However, antibiotic pressure certainly plays a major role. Selective pressure due to prolonged antibiotic exposure constitutes an independent risk factor which determines the colonization and infection status of MDR organisms (MDROs) in ICUs. It has been well-emphasized in a study, where cephalosporin-based prophylaxis was given in 2,641 consecutive patients who had undergone heart surgery for over 5 years. Prolonged prophylaxis (>48 h), as compared to short-term prophylaxis, is not encouraged since it is not associated with decreased risk of SSI; it, on the other hand, is clearly associated with increased risk of colonization with MDROs.
| Classification of Intensive Care Unit Infections|| |
Infections in ICUs are always crucial and need to be classified for any surveillance program. A time cutoff of 48 h has generally been accepted to distinguish between community-acquired and HAIs from the practical point of view. However, it might not be always a “true” HAI if it develops after 48 h of ICU stay, since the causative microorganism may not belong to the ICU microbial ecology, rather imported by the patient as normal flora of his/her body. The “traditional” approach is challenged with the concept of “carrier state,” when genotypically similar strains grew repeatedly at any concentration from samples taken on admission and then afterward twice weekly from body sites such as throat or rectal swab taken for surveillance purpose to detect potentially pathogenic microorganisms (PPMs). On the other hand, clinical samples are collected from the superficial sites of suggestive infection and from internal organs which are normally sterile such as lower respiratory tract, blood, and bladder while diagnosing local infections or systemic infections, respectively. The HAI has been classified on the basis of carrier status and diagnostic cultures as follows:
Primary endogenous infections
This is the most frequent form of infection in the ICUs, with an incidence between 50% and 85%, that occurs usually early, during the 1st week of ICU stay.,,,,, These may consist of both normal and abnormal PPMs and may be imported in the ICUs during admission of the patient.
Secondary endogenous infections
These usually occur after 1 week of ICU stay by aerobic MDR Gram-negative bacilli and Gram-positive cocci, especially MRSA and VRE. It accounts for one-third of all ICU infections.,,,,, These PPMs are first colonized in the oropharynx, and subsequently, in the stomach and the intestine, which can be prevented by the topical applications of nonabsorbable antimicrobials.
These are approximately 15% of all ICU-acquired infections, which are caused by the abnormal hospital PPMs at any time during the patient's stay in the ICU.,,,,,Acinetobacter infection of lower respiratory tract of the patients is the typical example, especially when the patient is on long-standing ventilator care. Surveillance samples may be negative for the microorganisms, but they readily appear in the clinical samples. These type of infections are difficult to treat, rather more feasible to control by high level of hygiene.
According to the criterion, ICU-acquired infections are only secondary endogenous and exogenous infections, whereas primary endogenous infections are usually imported by the patient while during admission.
| Surveillance of Infections in Intensive Care Units|| |
The surveillance has been recognized as the major component of infection control since late 1970s. It has been observed that there was a decrease in HAI rates on average 32% in hospitals with well-documented surveillance program in place over a 5-year period as compared with an increase of 18% in other hospitals without any such program. Epidemiological intervention following surveillance, control at the administrative level for medical devices used for critical patients as well as for the HCWs working in hospital setups, and also, control of biomedical engineering parameters are among others, the major distinct surveillance components in controlling HAIs HAIs [Table 1].
|Table 1: Elements of surveillance applied to infection control in Intensive Care Units|
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There can be total surveillance all over the hospital, which includes routine collection, tabulation, analysis, and circulation of data regarding the prevalence of HAIs in specified areas. Target-oriented surveillance usually is restricted to objectives on the priority basis as decided in the local settings, for example, control of the spread of MDR Gram-negative bacteria in developing countries, MRSA in the developed countries or reduction of the incidence of CRBSI or urinary tract infections, which are universal problem in every setting. Last but not the least, infection-specific surveillance targets toward particular types of infection-related events, for example, surveillance of outbreaks or generating antibiogram in the microbiology laboratory while formulating antibiotic policy in the hospital [Table 2]. There are a number of definite tools which are applied for infection control in ICU: Chart review, Laboratory Data, ICU Documents Review, Temperature, Antibiotics Review, Readmission, and Autopsy [Table 2]. The time required to implement these tools may vary according to the number of beds under surveillance.
|Table 2: Concepts and tools for surveillance of hospital acquired infections|
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In practical terms, optimal use of the resources in resource-limited settings, relentless monitoring of different infections, especially due to MDROs, to detect and control outbreaks are essential for both specific and emergency measures, which may further help design targeted programs to reduce number of HAIs.
Critical care bundle therapy
A “Bundle” is a structured way to improve patient care and outcomes by following straightforward, well-defined, checklist-based set of evidence-based practices and it is an essential part of surveillance for infection in ICUs. The bundles which are prepared as an objective, bedside practice-based approach with 3–5 elements in each have shown significant reduction in HAIs and improvement in patient outcomes. The Institute of Healthcare Improvement, USA has with the power of providing a reliable, best possible health care for patients without any chance of infection from the setting itself, only when executed with complete consistency. The bundles are derived from well-established practices. Failure of execution of bundles most often makes the treatment unreliable, at times idiosyncratic. There is a clear-cut impact of successfully implemented bundle if it is followed religiously and regularly as a continuous process. It is all or none, for example, “Yes, I completed the ENTIRE bundle” or “No, I did not complete the ENTIRE bundle.” There is no credit for partial completion (doing few steps for once or some days).
At least, there are two bundles which need to be implemented in all ICUs at the initial stage:
Central line maintenance bundle
The following steps may help prevent CLABSI: (1) Daily review of line necessity, (2) Hand hygiene before manipulation of the intravenous (IV) system, (3) Daily inspection of the insertion site, (4) Catheter-site care, and (5) Alcohol scrub of insertion hubs for 15 s before each use.
Ventilator-associated pneumonia is a well-encountered infection of lower respiratory tract, which may have a fatal outcome for the patients who are receiving mechanical ventilation, especially for longer duration. The ventilator bundles have following steps: (1) Elevation of the head end of the bed between 30° and 40°, (2) Mouth care with 1%–2% Chlorhexidine (6 h), (3) Subglottic aspiration 1–2 h, (4) Daily sedation vacation, (5) Daily assessment of readiness to wean, (6) Daily spontaneous breathing trial, (7) Peptic ulcer disease prophylaxis, and (8) Deep venous thrombosis prophylaxis.
Control and prevention of infections in intensive care units
Prevention plays a major role in the control of infections in ICUs, which can be implemented through various guidelines. However, the main approaches are schematized as follows:First, the potential sources of pathogens which may be responsible for transmitting infection from one patient to another, or to HCWs need to be identified and controlled, and the techniques to prevent cross-contamination such as proper cleaning, disinfection, and maintenance of various equipment or devices need to be documented and practiced; second, for selected group of patients, who need surgical antibiotic prophylaxis or empirical therapy guidelines need to be in place and strictly in use; third, appropriate strategies to restrict the use of higher antibiotics and prevent the emergence of MDROs need to be implemented and followed up at regular interval to check the effectiveness. Added to this, some more measures which are specifically targeted to curb the infections in ICUs are listed below:
It has been documented that >50% patients while being admitted in ICUs have already been colonized with the potential pathogens that are responsible for infection in due course subsequently. A prospective observational study from a tertiary care center from the southern part of India showed that there were 4.28% MRSA, 18.58% ESBL Enterobacteriaceae, and 2.65% VRE asymptomatic carriers among 210 newly admitted adult patients; among them, 14.28% had monobacterial carrier stage. Although surgical admissions were more at risk (5.03 times; 95% CI: 1.3–19.6; P = 0.023) than medical, and 55.5% MRSA carriers, 61.9% ESBL Enterobacteriaceae carriers, and 100% VRE carriers underwent invasive procedures including surgery, IV or urinary catheterization, there was no evidence of infection due to their colonization status. However, some patients may acquire the infection from the hospital environment. Microorganisms can be transmitted by air-borne, tiny droplets or large-particle droplets, or by direct contact. Patients who are detected as colonizer or carrier of MDROs through active surveillance are isolated, either by nurse cohorting or contact isolation, so that the potential pathogens are not transmitted to other patients. The responsibility lies with the HCWs, who need to wear gown and gloves and wash their hands for all 5 moments as recommended by the WHO at the bedside as a mandatory practice to prevent transmission to other patients, especially to the patient who is designated to be on contact precautions. Airborne infection isolation rooms are set at the negative pressure (> −2.5 Pa) with >12 air exchanges per hour for airborne disease patients to prevent transmission of airborne microorganisms from the room to the adjacent rooms or corridors. Protective environment rooms housing severely neutropenic patients are set at the positive pressure (> +2.5 Pa) with >12 air exchanges per hour so that the airborne pathogens are not able to come from adjacent rooms, spaces, or corridors to contaminate the airspace occupied by such high-risk patients. It may further be enforced by self-closing doors, which may help maintain the correct pressure difference.
Ignaz Semmelweis, the obstetrician from Vienna >150 years ago, used chlorinated lime water as the first ever example of systemic hand disinfection while examining patients and showed a dramatic reduction of mortality related to puerperal fever. Since then, routine hand washing before and after patient contact remains the most important infection control measure., Transmission of exogenous Staphylococcus or other potential pathogens, especially in the ICUs where patient care necessitates frequent contact, by the hands of HCWs is well-documented.,,,,, Higher contamination was documented with handling of the body fluid secretions, respiratory care, maintaining devices, or in any such occasions where the sequence of patient care is interrupted. Standard precautions like hand hygiene, wearing gloves, mask, protective gears, and gowns should be mandatory requirements in any hospital setting [Table 3]. Appropriate hand disinfection before patient care may reduce 68 CFU of bacterial load, independent of the types of care provided and the location of the hospital. ICUs all over the world have always had a low-level compliance with hand hygiene, hardly exceeding 40%; lame excuses given are higher priority work over required hand-wash procedures, less time, inconvenient approach to hand wash facility, allergy or intolerance to hand-hygiene solutions, lack of leadership from administration, etc.
Alcohol-based hand rubs using antimicrobial agents such as chlorhexidine, instead of hand washing with alcohol and soap reduces the rate of HAIs more efficiently., Gloves must be used for any anticipated contact with blood or body fluids, mucous membrane, nonintact skin, secretions, and moist body substances of all patients. Gloves should be changed between contacts with the patients; in addition, gowns and masks may protect mucous membranes of the eyes, nose, and mouth from splashes or sprays of blood, body fluid secretions, and excretions during procedures and patient care activity [Table 3].
In addition to standard precautions, there were other precautions such as airborne, contact, droplet to prevent transmission of microorganisms. The droplet nuclei with <5 μm in size may remain suspended in the air for long periods and can travel long distance in patients with pulmonary tuberculosis, varicella and disseminated zoster, acute viral hemorrhagic fever, H1N1 influenza, or measles. These patients should be placed in a private room with negative air pressure. High-efficiency masks such as N-95 standard are required for HCWs or visitors, and also for the patient during transport outside the specified room.
When the infective microorganisms can be transmitted by larger particles (>5 μm in size) during coughing, sneezing and talking, or during invasive procedures such as bronchoscopy, pleural tap, endotracheal or tracheal aspiration, and suctioning, droplet precaution needs to be adopted. There are cases with Haemophilus influenzae type B, meningococci, MDR pneumococci or any other MDROs in respiratory tract (e.g., MRSA, ESBLs, CRE), pharyngeal diphtheria, mycoplasma pneumonia, and some viral diseases such as Adeno, Influenza, Mumps, Parvo B-19, and Rubella, where the microorganisms may be inhaled or can be deposited on the mucous membrane of host's eyes, nose, and mouth. However, a HCW must wear a mask when he/she comes in contact within 60 cm to 1 m of any such patient.
If suitable isolation room or a private room is unavailable in any hospital, the patient for airborne or droplet precautions may be cared for in cohort with another patient infected with the same organism. However, like airborne precautions, special air handling and ventilation are not necessary in case of droplet precaution. Few PPMs such as MRSA, VRE, ESBLs, CRE, or C. difficile can be transmitted by direct physical contact or indirect contact with the patient's environment. It is mandatory for the HCWs that they should wear gloves and gowns and discard them properly before leaving the room. Systematic hand hygiene measures should be strictly maintained before and after the examination or procedure. Patient care devices such as stethoscopes, blood pressure cuffs, and knee hammer should be rigorously cleaned and disinfected before being used on another patient. If the patient is immunocompromised or severely neutropenic, separate isolation room facility in a private room with filtered air instilled in positive pressure should be provided. However, due to lack of proper infrastructure in overcrowded hospitals in the developing countries, even shifting the patient to the corner of the ward or ICU with strict barrier nursing practice may suffice the requirement. Patients who are readmitted to the same hospital or are transferred from other hospital are possibly carrying and transmitting MDROs. These patients should be screened on admission and be segregated in isolation if they have any infection with PPMs during readmission.
Control of antimicrobial uses
The misuse of antimicrobial agents is one of the major determinants in the evolution of MDR strains in the hospital settings. Several strategies such as optimal use of the antimicrobial agents, strict implementation of antibiotic policy, removal or restriction of higher/reserve antibiotics from routine use as empirical agents, use of antimicrobial agents in combination, and cycling of the antibiotics have been tried to curb the misuse of the antimicrobial agents and control the emergence of resistance. However, it is already established that selection of antimicrobial agents is crucial at the bedside. There is always definitive therapy for proven infections, which is determined according to the antimicrobial sensitivity report. In few selective occasions, there is prophylaxis for specific infections, which is uniformly standardized all over the world. In case of empirical therapy for suspicion of infection, which constitutes the large majority of cases, there is always a chance of misuse of antibiotics, unless there is a local antibiotic policy in place. It may be essential in a few occasions, considering the high mortality and morbidity associated with nosocomial infection with MDROs that early empirical broad-spectrum antimicrobial coverage for critically ill patients needs to be started. However, every empirical therapy should be guided by hospital antibiotic policy, prepared on the basis of local antibiotic susceptibility data, and has to be reevaluated based on the initial culture results and clinical response of the patients after 48–72 h. In a study with patients suffering from pneumonia, either community or hospital-acquired, it is found that the mortality rate of patients receiving inadequate treatment (52%) was significantly higher than that for those receiving adequate treatment (12%). Guidelines for systematic evaluation of fever in critically ill patients to recognize nosocomial infection at the earliest along with implementation of antibiotic policy reduce cost and mortality of the patients in medical and surgical ICUs. It is essential to have a good knowledge of the total epidemiology and resistance profile of the hospital and community pathogens, and to have a multidisciplinary approach, which includes clinical microbiologists and experts in Infectious Diseases and Infection Control to solve the challenging cases.
Attitudes of health-care workers toward infection control
It has been emphasized that control of the HAIs is mainly related to teamwork and leadership. Moreover, there should be effective communication in place and guidelines to be followed to improve patient care. However, implementation is difficult in clinical practice, since most guidelines, requirements, and measures are unpopular with HCWs, who have to practice them at the bedside. It depends on the quality of a successful leader or the “Champion,” where an organized team under a leadership brings the changes through interaction and communication on daily basis. It is not as easy as it sounds and it is probably because noncompliance is connected with the yearning of human being for liberty. Noncompliance as related to several aspects of human behavior may include the false perception of an impending risk, or the underestimation of individual responsibility in the epidemiology of the institution, or passive attitudes regarding the increased complexity of the process of care, nor the least, the negative impact of the socioeconomic constraints that are responsible for understaffing.
| Conclusion|| |
It is estimated that more than one-third of HAIs are acquired in various ICUs, which roughly accounts for a crude incidence of 15%–40% of all hospital admissions. Although infection is not always the single most cause for mortality for patients in ICUs, it is definitely associated with increased length of stay and excessive hospital cost.,,, An improved knowledge of clinical epidemiology, microbial etiology, and pathophysiology of the disease will help understand the concepts of infection control, and thereby, the right use of antibiotics. In developing countries, where rapid turnover of workforce, lack of structured ICUs, and inadequate awareness of infection control practices are predominant, prevention of HAIs in the ICUs to provide better health care is always a challenge. Infection control in an ICU or in a hospital can never be stand-alone actions; rather it should be a part of everyday flow of work, where HCWs must be focused on it as part of their essential duty, for the patients and for themselves as well.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]