The new frontier of diagnostics: Molecular assays and their role in infection prevention and control.

Recent advances in technology over the last decade have propelled the microbiology laboratory into a pivotal role in infection prevention and control. The rapid adaptation of molecular technologies to the field of clinical microbiology now greatly influences infectious disease management and significantly impacts infection control practices. This review discusses recent developments in molecular techniques in the diagnosis of infectious diseases. It describes the basic concepts of molecular assays, discusses their advantages and limitations, and characterizes currently available commercial assays with respect to cost, interpretive requirements, and clinical utility.

Outbreak of Pantoea agglomerans Bloodstream Infections at an Oncology Clinic-Illinois, 2012-2013.

OBJECTIVE To determine the source of a healthcare-associated outbreak of Pantoea agglomerans bloodstream infections. DESIGN Epidemiologic investigation of the outbreak. SETTING Oncology clinic (clinic A). METHODS Cases were defined as Pantoea isolation from blood or catheter tip cultures of clinic A patients during July 2012-May 2013. Clinic A medical charts and laboratory records were reviewed; infection prevention practices and the facility's water system were evaluated. Environmental samples were collected for culture. Clinical and environmental P. agglomerans isolates were compared using pulsed-field gel electrophoresis. RESULTS Twelve cases were identified; median (range) age was 65 (41-78) years. All patients had malignant tumors and had received infusions at clinic A. Deficiencies in parenteral medication preparation and handling were identified (eg, placing infusates near sinks with potential for splash-back contamination). Facility inspection revealed substantial dead-end water piping and inadequate chlorine residual in tap water from multiple sinks, including the pharmacy clean room sink. P. agglomerans was isolated from composite surface swabs of 7 sinks and an ice machine; the pharmacy clean room sink isolate was indistinguishable by pulsed-field gel electrophoresis from 7 of 9 available patient isolates. CONCLUSIONS Exposure of locally prepared infusates to a contaminated pharmacy sink caused the outbreak. Improvements in parenteral medication preparation, including moving chemotherapy preparation offsite, along with terminal sink cleaning and water system remediation ended the outbreak. Greater awareness of recommended medication preparation and handling practices as well as further efforts to better define the contribution of contaminated sinks and plumbing deficiencies to healthcare-associated infections are needed. Infect Control Hosp Epidemiol 2017;38:314-319.

Acute hepatitis B outbreaks related to fingerstick blood glucose monitoring in two assisted living facilities.

OBJECTIVES: To establish the etiology for outbreaks of hepatitis B virus (HBV) infections at two assisted living facilities (ALFs) and devise appropriate control measures. DESIGN: Multisite outbreak investigations, retrospective cohort. SETTING: Two ALFs in Illinois. PARTICIPANTS: Facility A residents (n=120) and Facility B residents (n=105) and nursing staff (n=6). MEASUREMENTS: For Facility A, a retrospective cohort study to identify risk factors for HBV infection through serological testing of all residents and a medical record extraction. For Facility A and B, investigation of fingerstick blood glucose monitoring techniques. For Facility B, serological HBV testing of nurses and residents receiving fingerstick blood glucose monitoring. RESULTS: At Facility A, five confirmed acute, two probable acute, and one probable chronic HBV infections were identified in the 109 residents tested. All of the eight identified residents with HBV infection had diabetes mellitus. HBV deoxyribonucleic acid (DNA) sequences from the chronic and acute cases were identical. Transmission of HBV was associated with fingerstick blood glucose monitoring (relative risk (RR)=28.5, 95% confidence interval (CI)=1.6-498; P<.001) and insulin injections (RR=7.4, 95% CI=1.3-40.8; P=.03). At Facility B, seven of 21 residents (33.3%) receiving fingerstick blood glucose monitoring had evidence of recent HBV infection. CONCLUSION: Nurses probably transmitted HBV infection from resident to resident during fingerstick blood glucose monitoring in two separate ALFs, causing outbreaks. Awareness of the high risk for HBV transmission during procedures for the care of diabetes mellitus was limited. Following established infection control measures is critical to prevent spread of this highly contagious virus.

Outbreak of human adenovirus type 3 infection in a pediatric long-term care facility--Illinois, 2005.

BACKGROUND: Human adenovirus type 3 (HAdV-3) causes severe respiratory illness in children, but outbreaks in long-term care facilities have not been frequently reported. We describe an outbreak of HAdV-3 infection in a long-term care facility for children with severe neurologic impairment, where only 3 of 63 residents were ambulatory. METHODS: A clinical case of HAdV-3 was defined as fever (temperature, > or = 38.0 degrees C) and either a worsening of respiratory symptoms or conjunctivitis in a resident, with illness onset from June through August 2005. We reviewed medical records; conducted surveillance for fever, conjunctivitis, and respiratory symptoms; and collected nasopharyngeal and conjunctival specimens from symptomatic residents. Specimens were cultured in HAdV-permissive cell lines or were analyzed by HAdV-specific polymerase chain reaction assay. RESULTS: Thirty-five (56%) of 63 residents had illnesses that met the case definition; 17 patients (49%) were admitted to intensive care units, and 2 (6%) died. Patients were hospitalized in the intensive care unit for a total of 233 patient-days. Illness onset dates ranged from 1 June through 24 August 2005. Thirty-two patients (91%) had respiratory infection, and 3 (9%) had conjunctivitis. HAdV was identified by culture or PCR in 20 patients. Nine isolates were characterized as HAdV-3 genome type a2. CONCLUSIONS: Considering the limited mobility of residents and their reliance on respiratory care, transmission of HAdV-3 infection during this outbreak likely occurred through respiratory care provided by staff. In environments where patients with susceptible underlying conditions reside, HAdV infection should be considered when patients are identified with worsening respiratory disease, and rapid diagnostic tests for HAdV infection should be readily available to help identify and curtail the spread of this pathogen.

Multicenter intervention program to increase adherence to hand hygiene recommendations and glove use and to reduce the incidence of antimicrobial resistance.

OBJECTIVE: To determine whether a multimodal intervention could improve adherence to hand hygiene and glove use recommendations and decrease the incidence of antimicrobial resistance in different types of healthcare facilities. DESIGN: Prospective, observational study performed from October 1, 1999, through December 31, 2002. We monitored adherence to hand hygiene and glove use recommendations and the incidence of antimicrobial-resistant bacteria among isolates from clinical cultures. We evaluated trends in and predictors for adherence and preferential use of alcohol-based hand rubs, using multivariable analyses. SETTING: Three intervention hospitals (a 660-bed acute and long-term care hospital, a 120-bed community hospital, and a 600-bed public teaching hospital) and a control hospital (a 700-bed university teaching hospital).Intervention. At the intervention hospitals, we introduced or increased the availability of alcohol-based hand rub, initiated an interactive education program, and developed a poster campaign; at the control hospital, we only increased the availability of alcohol-based hand rub. RESULTS: We observed 6,948 hand hygiene opportunities. The frequency of hand hygiene performance or glove use significantly increased during the study period at the intervention hospitals but not at the control hospital; the maximum quarterly frequency of hand hygiene performance or glove use at intervention hospitals (74%, 80%, and 77%) was higher than that at the control hospital (59%). By multivariable analysis, preferential use of alcohol-based hand rubs rather than soap and water for hand hygiene was more likely among workers at intervention hospitals compared with nonintervention hospitals (adjusted odds ratio, 4.6 [95% confidence interval, 3.3-6.4]) and more likely among physicians (adjusted odds ratio, 1.4 [95% confidence interval, 1.2-1.8]) than among nurses at intervention hospitals. A significantly reduced incidence of antimicrobial-resistant bacteria among isolates from clinical culture was found at a single intervention hospital, which had the greatest increase in the frequency of hand hygiene performance. CONCLUSIONS: During a 3-year period, a multimodal intervention program increased adherence to hand hygiene recommendations, especially to the use of alcohol-based hand rubs. In one hospital, a concomitant reduction was found in the incidence of antimicrobial-resistant bacteria among isolates from clinical cultures.

Chlorhexidine gluconate to cleanse patients in a medical intensive care unit: the effectiveness of source control to reduce the bioburden of vancomycin-resistant enterococci.

BACKGROUND: Historically, methods of interrupting pathogen transmission have focused on improving health care workers' adherence to recommended infection control practices. An adjunctive approach may be to use source control (eg, to decontaminate patients' skin). METHODS: We performed a prospective sequential-group single-arm clinical trial in a teaching hospital's medical intensive care unit from October 2002 to December 2003. We bathed or cleansed 1787 patients and assessed them for acquisition of vancomycin-resistant enterococci (VRE). We performed a nested study of 86 patients with VRE colonization and obtained culture specimens from 758 environmental surfaces and 529 health care workers' hands. All patients were cleansed daily with the procedure specific to the study period as follows: period 1, soap and water baths; period 2, cleansing with cloths saturated with 2% chlorhexidine gluconate; and period 3, cloth cleansing without chlorhexidine. We measured colonization of patient skin by VRE, health care worker hand or environmental surface contamination by VRE, and patient acquisition of VRE rectal colonization. RESULTS: Compared with soap and water baths, cleansing patients with chlorhexidine-saturated cloths resulted in 2.5 log(10) less colonies of VRE on patients' skin and less VRE contamination of health care workers' hands (risk ratio [RR], 0.6; 95% confidence interval [CI], 0.4-0.8) and environmental surfaces (RR, 0.3; 95% CI, 0.2-0.5). The incidence of VRE acquisition decreased from 26 colonizations per 1000 patient-days to 9 per 1000 patient-days (RR, 0.4; 95% CI, 0.1-0.9). For all measures, effectiveness of cleansing with nonmedicated cloths was similar to that of soap and water baths. CONCLUSION: Cleansing patients with chlorhexidine-saturated cloths is a simple, effective strategy to reduce VRE contamination of patients' skin, the environment, and health care workers' hands and to decrease patient acquisition of VRE.

Computer algorithms to detect bloodstream infections.

We compared manual and computer-assisted bloodstream infection surveillance for adult inpatients at two hospitals. We identified hospital-acquired, primary, central-venous catheter (CVC)-associated bloodstream infections by using five methods: retrospective, manual record review by investigators; prospective, manual review by infection control professionals; positive blood culture plus manual CVC determination; computer algorithms; and computer algorithms and manual CVC determination. We calculated sensitivity, specificity, predictive values, plus the kappa statistic (kappa) between investigator review and other methods, and we correlated infection rates for seven units. The kappa value was 0.37 for infection control review, 0.48 for positive blood culture plus manual CVC determination, 0.49 for computer algorithm, and 0.73 for computer algorithm plus manual CVC determination. Unit-specific infection rates, per 1,000 patient days, were 1.0-12.5 by investigator review and 1.4-10.2 by computer algorithm (correlation r = 0.91, p = 0.004). Automated bloodstream infection surveillance with electronic data is an accurate alternative to surveillance with manually collected data.

Unnecessary use of central venous catheters: the need to look outside the intensive care unit.

We developed criteria for justifiable CVC use and evaluated CVC use in a public hospital. Unjustified CVC-days were more common for non-ICU patients compared with ICU patients. Also, insertion-site dressings were less likely to be intact on non-ICU patients. Interventions to reduce CVC-associated bloodstream infections should include non-ICU patients.

Impact of ring wearing on hand contamination and comparison of hand hygiene agents in a hospital.

We determined risk factors for hand contamination and compared the efficacy of 3 randomly allocated hand hygiene agents in a group of surgical intensive care unit nurses. We cultured samples of one of the subjects' hands before and samples of the other hand after hand hygiene was performed. Ring wearing was associated with 10-fold higher median skin organism counts; contamination with Staphylococcus aureus, gram-negative bacilli, or Candida species; and a stepwise increased risk of contamination with any transient organism as the number of rings worn increased (odds ratio [OR] for 1 ring worn, 2.6; OR for >1 ring worn, 4.6). Compared with use of plain soap and water, hand contamination with any transient organism was significantly less likely after use of an alcohol-based hand rub (OR, 0.3; 95% confidence interval [CI], 0.1-0.8) but not after use of a medicated hand wipe (OR, 0.9; 95% CI, 0.5-1.6). Ring wearing increased the frequency of hand contamination with potential nosocomial pathogens. Use of an alcohol-based hand rub resulted in significantly less frequent hand contamination.

Adherence with hand hygiene: does number of sinks matter?

We observed adherence with hand hygiene in 14 units at 4 hospitals with varying sink-to-bed ratios (range, 1:1 to 1:6). Adherence was less than 50% in all units and there was no significant trend toward improved hand hygiene with increased sink-to-bed ratios.