Which component of hand washing is most important for removing microorganisms?

Hand Hygiene

Hand disinfection is the cornerstone of infection prevention, and many studies have demonstrated that alcohol-based hand rubs are to be preferred over handwashing with water and soap.17,18 However, the scientific evidence for this intervention is rather thin, as concluded in systemic reviews by Cochrane and the World Health Organization.17,18 After publication of these reviews some evidence has been added. One piece came from a recently published European multicenter study, in which a hand hygiene improvement program was implemented in 13 ICUs in eight countries.14 Based on 41 558 observations of hand hygiene opportunities by trained research nurses, hand hygiene adherence was, on average, 52% in the 6-month baseline period, and improved by 12% per month after implementation, reaching a plateau level of 77%. At the same time universal chlorhexidine body washing was implemented. The combination of these two interventions was associated with a weekly reduction of acquisition of carriage with either MRSA, VRE or ESBL of 3%, which mainly resulted from a reduction in acquisition of MRSA.14

Preparations for Hand Hygiene

Washing the hands with soap causes suspension and mechanical removal of microorganisms and dirt from the hands. Hand disinfection refers to the same process, but with the use of an antimicrobial product to kill or inhibit microorganisms. Table 40-3 compares properties of the various hand hygiene agents.

The cleansing activity of plain soap results from its detergent properties (Boyce et al, 2002). Hand washing with soap alone reduces bacterial colonization of the hands, but has no significant antimicrobial activity and is ineffective at removing pathogenic flora. Soaps containing antimicrobial agents are typically used in the NICU environment.

The antimicrobial activity of alcohol stems from its ability to denature proteins (Boyce et al, 2002). Because proteins are not readily denatured in the absence of water, solutions containing 50% to 80% alcohol are most effective (Boyce, 2000; Boyce et al, 2002). Alcohol has a rapid onset of action and reduces bacterial colonization, but has no residual activity. The efficacy of alcohol-based products is influenced by the type of alcohol used, concentration, contact time, volume used, and whether the hands are wet when the product is applied (Boyce et al, 2002; Mackintosh and Hoffman, 1984). When used in adequate amounts, alcohol is usually more effective than other hand hygiene products (Boyce, 2000; Boyce et al, 2002).

Chlorhexidine gluconate is a cationic bis-biguanide whose antimicrobial activity is caused by attachment and disruption of cytoplasmic membranes (Boyce et al, 2002). The onset of action is slower than the alcohol-based preparations; however, its major benefit is the persistent antimicrobial activity, which may last up to 6 hours after application (Boyce et al, 2002; Larson, 1995). Varying percentages of this product have been added to other hand hygiene preparations, especially the alcohol-based preparations, to confer greater residual activity.

Hexachlorophene is a bisphenol compound with bacteriostatic properties. Its activity is due to its ability to inactivate essential enzymes systems. It has good activity against S. aureus, but weak activity against gram-negative bacteria, fungi, and Mycobacterium tuberculosis. Hexachlorophene also has residual activity. Hexachlorophene was used for routine bathing of newborn infants until 1972, when the U.S. Food and Drug Administration (FDA) warned against its use because of an increased occurrence of cystic degeneration of the cerebral white matter in infants who had been bathed in the 3% solution (Shuman et al, 1975). This product should be considered only in term infants during a severe outbreak of S. aureus. Most experts recommend diluting the material 1:4 with water to decrease the risk of systemic absorption.

Iodine and iodophors penetrate the cell walls of organisms, impairing protein synthesis and altering the cellular membranes (Boyce et al, 2002). The amount of iodine present determines the level of antimicrobial activity. Combining iodine with polymers (i.e., povidone or poloxamer) increases the solubility, promotes sustained release of iodine, and decreases skin irritation. The activity of this product is affected by pH, exposure time, temperature, the presence of organic (blood or sputum) or inorganic material, and the concentration of iodine.

Prevention in Travelers

Prevention of RTIs in the traveler as in all individuals usually relies on behavioral changes (hand-washing or hand disinfection with alcohol-based liquid sanitizers and avoidance of close contact with sick individuals), vaccination, and rarely chemoprophylaxis (e.g., antiinfluenza medication during an outbreak) (Table 59.2).

Influenza, measles, diphtheria, pertussis, as well as pneumococcal and Hib-associated infections are vaccine-preventable diseases. All travelers should be up to date with antimeasles, antiinfluenza, antidiphtheria, and antipertussis vaccines (e.g., Tdap: tetanus, antidiphtheria, acellular pertussis vaccine). All children should be up to date with anti-H. influenzae b immunization (Hib) and pediatric pneumococcal polyvalent vaccine. All adults 65 years of age or older, or with certain indications, should be up to date for adult pneumococcal vaccination.28 All travelers should be up to date for immunization against influenza.4,29

Control measures for legionellosis are based on the application of guidelines for maintaining safe water systems in international tourist locations and cruise ships.30 The early recognition of outbreaks is exceedingly important in the management of individual cases of diseases such as legionellosis. The European Legionnaires' Disease Surveillance Network (ELDSNET) reports legionella cases diagnosed in patients who have been traveling within the likely incubation period of 2 weeks, together with geographic location of suspected source of transmission. Members of the group report cases of legionnaires disease to the coordinating center, which then notifies all members of any disease cluster. Other international global and regional surveillance networks, including GeoSentinel, TropNet, and EuroTravNet, play a pivotal role in early detection and public warning of travel-related epidemics.31,32

International health authorities may impose and have imposed public health interventions during worrisome outbreaks (e.g., H5N1 and H1N1 influenza, and SARS), including animal culling, travel restrictions, screening at airports and points of arrival and departure, and quarantine in efforts to limit the spread of respiratory infections.

Patient Education and Care of Driveline Exit Site

Patient and partner education and strict compliance to the standard care procedure in preventing driveline infections has been associated with a significantly reduced incidence of infections [73,74]. Hand and skin disinfection, exit site preparation, using maximal sterile barrier precautions such as antimicrobial dressing, and limiting the number of driveline manipulations are critical in the prevention of driveline infections [73,74]. Recently, the use of immobilizing devices, such as an abdominal binder, to minimize the risk of repeated microskin trauma was found to significantly decrease the risk of driveline infections [75,76]. However, despite the implementation of strict compliance to the standard insertion and care procedures, driveline infections are still frequently reported. This is probably due to less careful handling of drivelines by patients, or to increased stress on the driveline as the recovering VAD patient becomes more active [77].

Prevention of All Infections Through Promotion of Hand Hygiene (MRSA and MDR-GNR)

The most effective strategy to prevent infections with antibiotic-resistant bacteria is to adopt interventions likely to prevent all infections. Hand hygiene is thus central to any such program. Indeed, because newborns rapidly acquire their colonizing flora through exposure to their environment, hand disinfection is particularly important in the NICU.

Bacteria occupying the hands of health care workers are composed of two populations. The resident flora is relatively permanent and is made up of organisms of low pathogenic potential, particularly coagulase-negative staphylococci, diptheroids, and viridans streptococci.72 The transient population, composed of more dangerous microbes, colonizes the superficial layers of the dermis.72 Although contamination of caregiver hands by potentially pathogenic bacteria and fungi can occur with virtually any aspect of patient care, including contact with the patient's inanimate environment, selected frequently encountered activities, especially contact with respiratory secretions and diapers, are particularly prone to cause such contamination.73,74

Unlike the resident flora, bacteria composing the transient flora can be readily removed by hand hygiene. Even hand washing with nondisinfectant soap at least partially removes elements of the transient flora, probably largely through mechanical action. Use of a disinfectant, however, is required to reliably eradicate most of the transient flora. The compounds most commonly used for hospital disinfection are iodophors, chlorhexidine, and alcohol. All three agents have broad activity against Gram-positive and Gram-negative bacteria, fungi, and many viruses.72,75 Disinfectant-containing scrub brushes, traditionally employed in the past, are no longer recommended, because they promote skin breakdown, which, in turn, results in heavy bacterial growth on the hands. Iodophor and chlorhexidine hand disinfectants have a residual antibacterial effect that can last many hours when allowed to dry, but this requirement, if strictly applied, would occupy an inordinate amount of caregiver time.76 Alcohol-based disinfectants provide less residual activity, but they reduce hand bacterial concentrations rapidly,75 and they can be applied without a sink. These properties have rendered alcohol-based hand products the preferred agents for hand hygiene and prevention of nosocomial infections (NIs) in all areas of the hospital.72 Indeed, in a recent report from a Japanese NICU, promotion and use of alcohol-based hand disinfectant was the only intervention among several that was effective in reducing the presence of MRSA in the unit.18

Current standards require hand disinfection before and after contact with the patient or his or her immediate environment. Long nails (both artificial and natural) and hand jewelry should be avoided, because both can harbor a broad spectrum of potentially pathogenic microorganisms. Long nails in particular have been implicated in perpetuating nursery epidemics.77,78 Some authorities accept the use of gloves as a substitute for hand disinfection.74,79,80 Studies in the care of adults patients, however, have demonstrated that hands frequently can become contaminated during de-gloving,81 emphasizing the need to employ hand disinfection even with the use of gloves.

Despite the compelling logic underlying hand disinfection in the hospital setting, adherence to hand hygiene standards by health care workers generally has been abysmal, and surveys performed specifically in the NICU have recorded compliance rates as low as 22% to 28%.80,82 Recent experience both in and out of the NICU has made it clear that sustained improvement in hand hygiene among hospital workers will not occur unless a prolonged, ambitious, multifaceted effort is made.75 Uniformly, the most effective programs have been supported both administratively and financially by hospital officials and policy makers who have made it a visible, sustained priority for their institution. Personal investment and role modeling by attending staff are critical. Virtually every published program has incorporated regular hand hygiene audits over many months, frequently completed surreptitiously by unidentified observers, with immediate feedback to the staff in the targeted unit.75,83-86

Several recent studies have reported programs that have attempted to improve hand hygiene in the NICU setting and, secondarily, to reduce the incidence of NIs. Lam and colleagues83 instituted an aggressive program in a Hong Kong nursery in which step-by-step protocols were designed to improve hand hygiene during hands-on interventions. Adherence to hand hygiene was significantly improved and the incidence of NIs was reduced nearly in half, from 17.2 infections/100 admissions before the intervention to 9.0 infections/100 admissions afterward. A second program, in Geneva, Switzerland, employed an ambitious series of in-services and focus groups to similarly develop protocols regarding practices during direct patient care.84 Proper hand hygiene increased from 42% of opportunities to 55%, and the incidence of NIs among very low birth weight (VLBW) infants was reduced by one third—a benefit that persisted over a 9-month follow-up period. Taiwanese investigators86 achieved similar improvement in hand hygiene compliance and nosocomial infection rates by instituting a program using many of the same features, additionally establishing a schedule of financial penalties and awards for nursing staff according to their hand hygiene performance.

Other Approaches

Guidelines for the safe use of povidone iodine complexes

In 1985, a working group of the Federal German Medical Association issued a number of recommendations for the safe use of povidone iodine complexes [13]. They remain valid and can be summarized as follows:

The application of povidone iodine formulations cannot be recommended for surgical hand disinfection, since active iodine-free formulations are available.

The activity of povidone iodine in preoperative skin disinfection in adults is well proven.

Povidone iodine is appropriate for skin disinfection before an incision, a puncture, with use of intravenous or arterial catheters, and for the prophylaxis of iatrogenic Clostridia infections.

In the case of superficial wounds, povidone iodine can be applied occasionally or repeatedly in spite of increased iodine absorption through the broken skin surfaces.

Lavage of wound and body cavities with povidone iodine or its instillation is not indicated because of increased iodine absorption.

Routine body washing of patients in intensive care units is not cost-beneficial.

Vaginal administration of povidone iodine is not recommended.

Povidone iodine is contraindicated in premature babies and neonates; this also applies to prophylactic disinfection of the umbilical stump.

The clinical usefulness of povidone iodine in the treatment of burns is well proven.

Local mouth antiseptics serve no therapeutic purpose; this is also true for povidone iodine.

Postoperative Prophylaxis of Infection

Surgical patients are at especially high risk of HAI. Judicious preoperative antibiotic prophylaxis decreases the risk of infection, but this prophylaxis in the absence of other techniques will not accomplish much. Proper infection control practice cannot be emphasized enough. The use of fast-drying alcohol gels for hand disinfection improves compliance and can be used in the operating room and at the bedside. Care must be taken to use soap and water for hand disinfection when C. difficile toxin transmission is possible, as alcohol gels are ineffective in eradicating spores.

Surgery is invasive and surgical patients are often immunosuppressed owing to illness or injury;17,50 the surgical stress response augments the immunosuppression. Many standard interventions impair host defenses (see Table 76-1). Surgical care must minimize the possibility of iatrogenic infection, while supporting the patient until host defenses can recover.

Catheters and drains should be removed as soon as possible. Each time a natural epithelial barrier to infection (e.g. skin, respiratory tract mucosa, gut mucosa) is breached, a portal is created for potential invasion of the host by pathogens. Subcutaneous drains increase the risk of SSI.53 Prolonged central venous catheterization increases the risk of bacteremia; prolonged intubation and mechanical ventilation increase the risk of pneumonia. Moreover, prolonged urinary catheterization increases the risk of urinary tract infection. These devices should be removed as soon as feasible.54 Improved catheter designs and endotracheal tubes (e.g. silver impregnated tubes and tubes that aspirate subglottic secretions via an extra lumen) might decrease the risk of HAI further, but the best practice involves earliest possible discontinuation or avoidance of use altogether, if possible.

Although cumbersome and therefore not popular, topical antiseptics and antibiotics appear to decrease the risk of HAI in seriously ill, high-risk patients. Data demonstrate that topical 0.12% chlorhexidine mouthwash (a bactericidal, viricidal and fungicidal antiseptic) applied to the oropharynx and the exposed surface of the endotracheal tube decreases the incidence of postoperative pneumonia.55 Selective digestive decontamination (SDD),56 described in various forms nearly two decades ago, utilizes an oral paste of multiple antibiotics, enteral administration of the same antimicrobial agents by gavage and sometimes a short course of intravenous antibiotics. Infection rates are reduced unequivocally,52 and this practice has been widely adopted in some centers in Europe. However, out of concern for the potential promotion of antibiotic resistance, SDD has not gained acceptance in many other regions of the world. SDD has only recently been acknowledged, along with the ongoing controversy over its safety and efficacy, in the latest version of the Surviving Sepsis Campaign's International Guidelines for the Management of Severe Sepsis and Septic Shock.19 Daily bathing with chlorhexidine has been demonstrated among critically ill patients to have demonstrable effect on the rate of central line-associated bloodstream infection (CLABSI) caused by organisms commonly associated with skin colonization, as well as acquisition of multidrug-resistant organisms.57 However, this widely accepted horizontal strategy for infection control has been called into question in light of the contrasting results of a recently published single-center cluster randomized controlled trial of daily chlorhexidine bathing.58

Prophylaxis of fungal infections is controversial. Although surgical patients are immunosuppressed and are frequently exposed to antibiotics, invasive fungal infections are unusual. Although Candida spp. are frequently isolated from the peritoneal fluid of patients with peritonitis, specific antifungal therapy is generally not indicated unless Candida spp. are isolated in pure culture from blood, from peritoneal fluid or from an abscess. Fungemia can be associated with indwelling central venous catheters, but on the rare occasion when fungemia complicates surgery (solid organ transplant patients excepted), the patient is usually debilitated from a protracted serious illness and has already been exposed to multiple courses of antibiotics. Neither prophylactic nor empiric antifungal therapy is recommended for patients with community-acquired intra-abdominal infection, but rather should be directed by intra-abdominal cultures obtained at the time of surgery. However, empiric therapy can be considered in patients at high risk for disseminated candidiasis (e.g. steroid use, neutropenia and other immunocompromised states, gastro-duodenal or small bowel source of infection).59-61 Care should be taken to minimize overuse and tailor antifungals according to culture results, as widespread use of fluconazole has been associated with the emergence of azole-resistant strains of Candida, especially C. krusei.62

5.2 Nanoparticle Antibacterial Hand Gel

In these studies, researchers tried to find a better approach than what is currently available for use regarding hand antimicrobial effects. Hand antisepsis is a necessary procedure for all health professionals, sometimes multiple times a day. There is a deep and well-established correlation between hand antisepsis and infection rates. However, compliance with hand disinfection is often low, partially because of unwanted effects such as skin irritation (Kampf and Löffler, 2010). Therefore, we can see how easily hand gels that have a lasting antimicrobial effect can directly affect patient care. Two very similar studies were conducted starting in 2008 (Madigan Army Medical Center, 2008) and 2009 (Henry M. Jackson Foundation for the Advancement of Military Medicine, 2009) in which the antimicrobial effect of a silver nanoparticle gel was assessed. A report of the results was published in 2011 (Schlicher, 2011).

In the first study, in addition to the silver nanoparticle solution, an alcohol hand gel was used as control. Apart from the alcohol and nanosilver gels, in the second study they also used a combination gel that contained both alcohol and nanosilver particles in the formulation. The second trial was more complete and took into consideration the results of the first one. Therefore, we based our analysis on it. In this study, 53 patients were recruited. After subjects used one of the three gel formulations (alcohol, nanoparticle, or mixed), bacterial counts were obtained after 1 min for evaluation of immediate effect and after 30 min for evaluation of permanent effect. After obtaining bacterial counts, a questionnaire was given, addressing gel acceptability, providing information about the subjective perception of the product by users.

Despite the hypothesis, the alcohol-based gel could reduce colony forming units with greater ease in the short period. Regarding persistent efficacy, still no statistically significant difference between the three gel options existed. This finding contradicted a previous finding by the first study, where the nanoparticle gel showed to be better (considering 10 min as the time span for permanent effect). Therefore, according to the new findings brought by the second trial, there were no advantages in using one gel over another when trying to achieve a persistent effect in microorganism count after 30 min. On top of that, in the subjective analysis, users preferred the alcohol-based gel group, followed by the mixed solution, and last of all the silver gel. User confidence in the product, consideration of repeating the use, and recommending the nanogel also followed the same pattern, with the alcohol gel being superior.

Viral pathogens

Nosocomial viral infections can be a significant problem for neonates [132]. Introduction of common viral pathogens into the NICU can be associated with (1) admission of infants from the community, (2) health care workers who work while ill or infectious, and (3) visitors.