Chapter 125. Health Care– Associated Infections (Part 9) docx

Health Care– Associated Infections Part 9 Tuberculosis Important measures for the control of tuberculosis Chap.. exposed to infectious patients before isolation.. Inhalation of spores

Chapter 125 Health Care– Associated Infections

(Part 9)

Tuberculosis

Important measures for the control of tuberculosis (Chap 158) include prompt recognition, isolation, and treatment of cases; recognition of atypical presentations (e.g., lower-lobe infiltrates without cavitation); use of negative-pressure, 100% exhaust, private isolation rooms with closed doors and 6–12 or more air changes per hour; use of N95 "respirators" (approved by the National Institute for Occupational Safety and Health) by caregivers entering isolation rooms; possible use of high-efficiency particulate air filter units and/or ultraviolet lights for disinfecting air when other engineering controls are not feasible or reliable; and follow-up skin-testing of susceptible personnel who have been

exposed to infectious patients before isolation The use of new serologic tests, rather than skin tests, in the diagnosis of latent tuberculosis for infection control purposes is being studied

Group a Streptococcal Infections

The potential for an outbreak of group A streptococcal infection (Chap 130) should be considered when even a single nosocomial case occurs Most outbreaks involve surgical wounds and are due to the presence of an asymptomatic carrier in the operating room Investigation can be confounded by carriage at extrapharyngeal sites such as the rectum and vagina Health care workers in whom carriage has been linked to nosocomial transmission of group A streptococci are removed from the patient-care setting and are not permitted to return until carriage has been eliminated by antimicrobial therapy

Fungal Infections

Fungal spores are common in the environment, particularly on dusty surfaces When dusty areas are disturbed during hospital repairs or renovation, the spores become airborne Inhalation of spores by immunosuppressed (especially neutropenic) patients creates a risk of pulmonary and/or paranasal sinus infection

and disseminated aspergillosis (Chap 197) Routine surveillance among

neutropenic patients for infections with filamentous fungi, such as Aspergillus and

Fusarium, helps hospitals to determine whether they are facing unduly extensive

environmental risks As a matter of routine, hospitals should inspect and clean air-handling equipment, review all planned renovations with infection-control personnel and subsequently construct appropriate barriers, remove immunosuppressed patients from renovation sites, and consider the use of high-efficiency particulate air intake filters for rooms housing immunosuppressed patients

Legionellosis

Nosocomial Legionella pneumonia (Chap 141) is most often due to

contamination of potable water and predominantly affects immunosuppressed patients, particularly those receiving glucocorticoid medication The risk varies greatly within and among geographic regions, depending on the extent of hospital hot-water contamination and on specific hospital practices (e.g., inappropriate use

of nonsterile water in respiratory therapy equipment) Laboratory-based

surveillance for nosocomial Legionella should be performed, and a diagnosis of

legionellosis should probably be considered more often than it is If cases are detected, environmental samples (e.g., tap water) should be cultured If cultures

yield Legionella and if typing of clinical and environmental isolates reveals a

correlation, eradication measures should be pursued An alternative approach is to

periodically culture tap water in wards housing high-risk patients If Legionella is

found, a concerted effort should be made to culture samples from all patients with

nosocomial pneumonia for Legionella

Antibiotic-Resistant Bacteria

Control of antibiotic resistance, particularly in outbreaks (Table 125-3), depends on close laboratory surveillance, with early detection of problems; on aggressive reinforcement of routine asepsis (e.g., hand hygiene); on implementation of barrier precautions for all colonized and/or infected patients; on use of patient-surveillance cultures to more fully ascertain the extent of patient colonization; and on timely initiation of an epidemiologic investigation when rates increase Colonized personnel who are implicated in nosocomial transmission and patients who pose a threat may be decontaminated In a few ICUs, selective decontamination of patients has been used successfully as a temporary emergency control measure for outbreaks of infection due to gram-negative bacilli Other promising ICU control measures include daily bathing of patients with chlorhexidine and enforcement of environmental cleaning; in recent trials, each of these measures reduced cross-transmission of VRE The value of "search-and-destroy" methods—i.e., the use of active surveillance cultures to detect and isolate

the "resistance iceberg" of patients colonized with methicillin-resistant S aureus

(MRSA) or VRE—in non-outbreak settings has been controversial but is credited with elimination of nosocomial MRSA in the Netherlands and Denmark