Emily E. Sickbert-Bennett

Role of hospital surfaces in the transmission of emerging health care-associated pathogens: Norovirus, Clostridium difficile, and Acinetobacter species

Health care-associated infections (HAI) remain a major cause of patient morbidity and mortality. Although the main source of nosocomial pathogens is likely the patients endogenous flora, an estimated 20% to 40% of HAI have been attributed to cross infection via the hands of health care personnel, who have become contaminated from direct contact with the patient or indirectly by touching contaminated environmental surfaces. Multiple studies strongly suggest that environmental contamination plays an important role in the transmission of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus spp. More recently, evidence suggests that environmental contamination also plays a role in the nosocomial transmission of norovirus, Clostridium difficile, and Acinetobacter spp. All 3 pathogens survive for prolonged periods of time in the environment, and infections have been associated with frequent surface contamination in hospital rooms and health care worker hands. In some cases, the extent of patient-to-patient transmission has been found to be directly proportional to the level of environmental contamination. Improved cleaning/disinfection of environmental surfaces and hand hygiene have been shown to reduce the spread of all of these pathogens. Importantly, norovirus and C difficile are relatively resistant to the most common surface disinfectants and waterless alcohol-based antiseptics. Current hand hygiene guidelines and recommendations for surface cleaning/disinfection should be followed in managing outbreaks because of these emerging pathogens.

Outbreaks Associated with Contaminated Antiseptics and Disinfectants

The Centers for Disease Control and Prevention (CDC) has estimated that health care-associated infections account for an estimated 1.7 million infections, 99,000 deaths, and

Microbiology of ventilator-associated pneumonia compared with that of hospital-acquired pneumonia.

4.5 billion in excess health care costs annually (16). The key interventions used to control health care-associated infections include surveillance (27, 33), isolation of patients with communicable diseases (26) or multidrug-resistant pathogens (81), proper skin antisepsis prior to invasive procedures and hand hygiene by health care workers (12), and appropriate disinfection and sterilization of medical devices and environmental surfaces (73, 75, 79). Multiple nosocomial outbreaks have resulted from inadequate antisepsis or disinfection. Inadequate skin antisepsis may result from a lack of intrinsic antimicrobial activity of the antiseptic, a resistant pathogen, overdilution of the antiseptic, or the use of a contaminated antiseptic. The inadequate disinfection of medical devices or environmental surfaces may result from a lack of intrinsic antimicrobial activity of the disinfectant, an incorrect choice of a disinfectant, a resistant pathogen, overdilution of the disinfectant, an inadequate duration of disinfection, a lack of contact between the disinfectant and the microbes, or the use of a contaminated disinfectant. Editorials have noted that contaminated antiseptics and disinfectants have been the occasional vehicles of hospital infections for more than 50 years (20, 72, 76). This paper concisely reviews nosocomial outbreaks associated with the use of a microbiologically contaminated germicide and focuses on the currently recommended germicides.

A Multistate Outbreak of Serratia marcescens Bloodstream Infection Associated with Contaminated Intravenous Magnesium Sulfate from a Compounding Pharmacy

OBJECTIVE Nosocomial pneumonia is the leading cause of mortality attributed to nosocomial infection. Appropriate empirical therapy has been associated with improved survival, but data are limited regarding the etiologic agents of hospital-acquired pneumonia in nonventilated patients (HAP). This evaluation assessed whether the currently recommended empirical therapy is appropriate for both ventilator-associated pneumonia (VAP) and HAP by evaluating the infecting flora. DESIGN Prospectively collected hospitalwide surveillance data was obtained by infection control professionals using standard Centers for Disease Control and Prevention definitions. SETTING A tertiary care academic hospital. PATIENTS All patients admitted from 2000 through 2003. RESULTS A total of 588 episodes of pneumonia were reported in 556 patients: 327 episodes of VAP in 309 patients, and 261 episodes of HAP in 247 patients. The infecting flora in ventilated patients included gram-positive cocci (32.0% [oxacillin-susceptible Staphylococcus aureus {OSSA}, 9.25%; oxacillin-resistant Staphylococcus aureus {ORSA}, 17.75%]), gram-negative bacilli (59.0% (Pseudomonas aeruginosa, 17.50%; Stenotrophomonas maltophilia, 6.75%; Acinetobacter species, 7.75%), and miscellaneous pathogens (9.0%). The infecting flora in nonventilated patients included gram-positive cocci (42.59% [OSSA, 13.33%; ORSA, 20.37%]), gram-negative bacilli (39.63% [P. aeruginosa, 9.26%; S. maltophilia, 1.11%; Acinetobacter species, 3.33%), and miscellaneous pathogens (17.78%). CONCLUSIONS Our data demonstrated that patients with HAP, compared with those with VAP, had a similar frequency of infection with ORSA but less commonly had infections due to P. aeruginosa, Acinetobacter species, and S. maltophilia. However, the overall frequency of infection with these pathogens was sufficiently high to warrant the use of empirical therapy likely to be active against them. Our data supports using the currently recommended empirical therapy for both HAP and VAP.

Comparison of hospitalwide surveillance and targeted intensive care unit surveillance of healthcare-associated infections.

BACKGROUND In contrast to pharmaceutical manufacturers, compounding pharmacies adhere to different quality-control standards, which may increase the likelihood of undetected outbreaks. In 2005, the Centers for Disease Control and Prevention received reports of cases of Serratia marcescens bloodstream infection occurring in patients who underwent cardiac surgical procedures in Los Angeles, California, and in New Jersey. An investigation was initiated to determine whether there was a common underlying cause. METHODS A matched case-control study was conducted in Los Angeles. Case record review and environmental testing were conducted in New Jersey. The Centers for Disease Control and Prevention performed a multistate case-finding investigation; isolates were compared using pulsed-field gel electrophoresis analysis. RESULTS Nationally distributed magnesium sulfate solution (MgSO(4)) from compounding pharmacy X was the only significant risk factor for S. marcescens bloodstream infection (odds ratio, 6.4; 95% confidence interval, 1.1-38.3) among 6 Los Angeles case patients and 18 control subjects. Five New Jersey case patients received MgSO(4) from a single lot produced by compounding pharmacy X; culture of samples from open and unopened 50-mL bags in this lot yielded S. marcescens. Seven additional case patients from 3 different states were identified. Isolates from all 18 case patients and from samples of MgSO(4) demonstrated indistinguishable pulsed-field gel electrophoresis patterns. Compounding pharmacy X voluntarily recalled the product. Neither the pharmacy nor the US Food and Drug Administration could identify a source of contamination in their investigations of compounding pharmacy X. CONCLUSIONS A multistate outbreak of S. marcescens bloodstream infection was linked to contaminated MgSO(4) distributed nationally by a compounding pharmacy. Health care personnel should take into account the different quality standards and regulation of compounded parenteral medications distributed in large quantities during investigations of outbreaks of bloodstream infection.

Compliance with isolation precautions at a university hospital.

OBJECTIVES To assess the surveillance coverage obtained with Centers for Disease Control and Prevention (CDC)-recommended surveillance of healthcare-associated infections (HAIs), which is focused on intensive care units (ICUs) and emphasizes device-related infections (ie, those associated with central venous catheters, ventilators, and/or urinary catheters), compared with the surveillance coverage achieved by comprehensive hospitalwide surveillance. In addition, we assessed whether the infection rates in step-down units more resemble those in wards or ICUs. METHODS Review of prospectively obtained, comprehensive hospitalwide surveillance data from 2004 through 2005 for an acute care tertiary care hospital with approximately 700 beds. Surveillance data was obtained by trained infection control professionals using standard CDC criteria for HAIs. RESULTS CDC-recommended ICU surveillance for catheter-related bloodstream infection (BSI) and ventilator-associated pneumonia would have detected only 87 (21.4%) of 407 catheter-related BSIs and only 66 (37.9%) of 174 respiratory tract infections that occurred in the medical and surgical services. Only 31 (34.8%) of 89 infections caused by methicillin-resistant Staphylococcus aureus and 7 (31.8%) of 22 infections caused by vancomycin-resistant Enterococcus occurred in our adult ICUs. CONCLUSIONS Rates of HAIs were highest in the ICUs, intermediate in step-down units, and lowest in the wards. The rates of infections in the step-down units were more similar to those in the wards than to those in the ICUs. To prevent HAIs, more comprehensive surveillance may be indicated.

Review of Fungal Outbreaks and Infection Prevention in Healthcare Settings During Construction and Renovation

Compliance with isolation precautions recommended by the Centers for Disease Control and Prevention (CDC) was evaluated in 3 hospital-wide observational surveys. The compliance rate, by type of isolation, was as follows: droplet transmission, 100% (4 observations); airborne transmission, 61.5% (13 observations); contact isolation, 73.3% (165 observations); and protective isolation, 73.6% (72 observations). As with hand hygiene, there is suboptimal compliance with recommended isolation precautions.

Utility of International Classification of Diseases, Ninth Revision, Clinical Modification Codes for Communicable Disease Surveillance

Hospital construction and renovation activities are an ever-constant phenomenon in healthcare facilities, causing dust contamination and possible dispersal of fungal spores. We reviewed fungal outbreaks that occurred during construction and renovation over the last 4 decades as well as current infection prevention strategies and control measures. Fungal outbreaks still occur in healthcare settings, especially among patients with hematological malignancies and those who are immunocompromised. The causative pathogens of these outbreaks were usually Aspergillus species, but Zygomycetes and other fungi were occasionally reported. Aspergillus most commonly caused pulmonary infection. The overall mortality of construction/renovation-associated fungal infection was approximately 50%. The minimal concentration of fungal spores by air sampling for acquisition of fungal infections remains to be determined. Performing infection control risk assessments and implementing the recommended control measures is essential to prevent healthcare-associated fungal outbreaks during construction and renovation.

Effectiveness of ultraviolet devices and hydrogen peroxide systems for terminal room decontamination: Focus on clinical trials.

International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes have been proposed as a method of public health surveillance and are widely used in public health and clinical research. However, ICD-9-CM codes have been found to have variable accuracy for both health-care billing and disease classification, and they have never been comprehensively validated for use in public health surveillance. Therefore, the authors undertook a comprehensive analysis of the positive predictive values (PPVs) of ICD-9-CM codes for communicable diseases in 6 North Carolina health-care systems for the year 2003. Stratified random samples of patient charts with ICD-9-CM diagnoses for communicable diseases were reviewed and evaluated for their concordance with the Centers for Disease Control and Prevention surveillance case definitions. Semi-Bayesian hierarchical regression techniques were employed on the ensemble of disease-specific PPVs in order to reduce the overall mean squared error. The authors found that for the majority for diseases with higher incidence and straightforward laboratory-based diagnoses, the PPVs were high (>80%), with the important exception of tuberculosis, which had a PPV of 28.6% (95% uncertainty interval: 15.6, 46.5).

Completeness of Communicable Disease Reporting, North Carolina, USA, 1995–1997 and 2000–2006

Over the last decade, substantial scientific evidence has accumulated that indicates contamination of environmental surfaces in hospital rooms plays an important role in the transmission of key health care–associated pathogens (eg, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Clostridium difficile, Acinetobacter spp). For example, a patient admitted to a room previously occupied by a patient colonized or infected with one of these pathogens has a higher risk for acquiring one of these pathogens than a patient admitted to a room whose previous occupant was not colonized or infected. This risk is not surprising because multiple studies have demonstrated that surfaces in hospital rooms are poorly cleaned during terminal cleaning. To reduce surface contamination after terminal cleaning, no touch methods of room disinfection have been developed. This article will review the no touch methods, ultraviolet light devices, and hydrogen peroxide systems, with a focus on clinical trials which have used patient colonization or infection as an outcome. Multiple studies have demonstrated that ultraviolet light devices and hydrogen peroxide systems have been shown to inactivate microbes experimentally plated on carrier materials and placed in hospital rooms and to decontaminate surfaces in hospital rooms naturally contaminated with multidrug-resistant pathogens. A growing number of clinical studies have demonstrated that ultraviolet devices and hydrogen peroxide systems when used for terminal disinfection can reduce colonization or health care–associated infections in patients admitted to these hospital rooms.