Vital Signs: Health Care-Associated Legionnaires' Disease Surveillance Data From 20 States and a Large Metropolitan Area-United States, 2015.

BACKGROUND: Legionnaires' disease, a severe pneumonia, is typically acquired through inhalation of aerosolized water containing Legionella bacteria. Legionella can grow in the complex water systems of buildings, including health care facilities. Effective water management programs could prevent the growth of Legionella in building water systems. METHODS: Using national surveillance data, Legionnaires' disease cases were characterized from the 21 jurisdictions (20 U.S. states and one large metropolitan area) that reported exposure information for ≥90% of 2015 Legionella infections. An assessment of whether cases were health care-associated was completed; definite health care association was defined as hospitalization or long-term care facility residence for the entire 10 days preceding symptom onset, and possible association was defined as any exposure to a health care facility for a portion of the 10 days preceding symptom onset. All other Legionnaires' disease cases were considered unrelated to health care. RESULTS: A total of 2,809 confirmed Legionnaires' disease cases were reported from the 21 jurisdictions, including 85 (3%) definite and 468 (17%) possible health care-associated cases. Among the 21 jurisdictions, 16 (76%) reported 1-21 definite health care-associated cases per jurisdiction. Among definite health care-associated cases, the majority (75, 88%) occurred in persons aged ≥60 years, and exposures occurred at 72 facilities (15 hospitals and 57 long-term care facilities). The case fatality rate was 25% for definite and 10% for possible health care-associated Legionnaires' disease. CONCLUSIONS AND IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: Exposure to Legionella from health care facility water systems can result in Legionnaires' disease. The high case fatality rate of health care-associated Legionnaires' disease highlights the importance of case prevention and response activities, including implementation of effective water management programs and timely case identification.

Chlorine dioxide inactivation of bacterial threat agents.

AIMS: To evaluate the efficacy of chlorine dioxide (ClO(2)) against seven species of bacterial threat (BT) agents in water. METHODS AND RESULTS: Two strains of Bacillus anthracis spores, Yersinia pestis, Francisella tularensis, Burkholderia pseudomallei, Burkholderia mallei and Brucella species were each inoculated into a ClO(2) solution with an initial concentration of 2.0 (spores only) and 0.25 mg l(-1) (all other bacteria) at pH 7 or 8, 5 or 25°C. At 0.25 mg l(-1) in potable water, six species were inactivated by at least three orders of magnitude within 10 min. Bacillus anthracis spores required up to 7 h at 5°C for the same inactivation with 2.0 mg l(-1) ClO(2). CONCLUSIONS: Typical ClO(2) doses used in water treatment facilities would be effective against all bacteria tested except B. anthracis spores that would require up to 7 h with the largest allowable dose of 2 mg l(-1) ClO(2). Other water treatment processes may be required in addition to ClO(2) disinfection for effective spore removal or inactivation. SIGNIFICANCE AND IMPACT OF STUDY: The data obtained from this study provide valuable information for water treatment facilities and public health officials in the event that a potable water supply is contaminated with these BT agents.

Chlorine disinfection of Francisella tularensis.

AIMS: To determine the range of free available chlorine (FAC) required for disinfection of the live vaccine strain (LVS) and wild-type strains of Francisella tularensis. METHODS AND RESULTS: Seven strains of planktonic F. tularensis were exposed to 0·5 mg·l(-1) FAC for two pH values, 7 and 8, at 5 and 25°C. LVS was inactivated 2 to 4 times more quickly than any of the wild-type F. tularensis strains at pH 8 and 5°C. CONCLUSIONS: Free available chlorine residual concentrations routinely maintained in drinking water distribution systems would require up to two hours to reduce all F. tularensis strains by 4 log10. LVS was inactivated most quickly of the tested strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This work provides contact time (CT) values that are useful for drinking water risk assessment and also suggests that LVS may not be a good surrogate in disinfection studies.

Pseudo-outbreak of Mycobacterium abscessus Infection Caused by laboratory contamination .

OBJECTIVE: To investigate the cause(s) of an increased incidence of clinical cultures growing Mycobacterium abscessus at a hospital in Florida. DESIGN: Outbreak investigation. SETTING: University-affiliated, tertiary-care hospital. METHODS: A site visit was done during the first week of September 2006. We reviewed the medical records of patients from whom M. abscessus was recovered during the period from January 1, 2003, through June 30, 2006. We collected environmental samples from various sites and evaluated specimen processing procedures in the microbiology laboratory. Isolates of M. abscessus recovered from the environment and from 12 randomly selected patients who sought medical care in 2006 were compared by pulsed-field gel electrophoresis (PFGE). Follow-up case surveillance was continued through March 31, 2007. RESULTS: Specimens from 143 patients obtained from various anatomical sites grew M. abscessus on culture in 2005-2006, compared with specimens from 21 patients in 2003-2004. The 12 isolates from patients that were selected for molecular typing had indistinguishable PFGE patterns. Observations revealed no major breaches in the processing of mycobacterial specimens in the laboratory. Isolates grew only after prolonged incubation (mean +/- SD, 45 +/- 15 days) in test tubes containing diagonally oriented Middlebrook and Cohn 7H10 agar or Lowenstein-Jensen medium. Environmental samples obtained from the inside of the specimen incubator grew M. abscessus on culture. A test tube containing diagonally oriented, uninoculated Middlebrook and Cohn 7H10 agar that was incubated in the same incubator as clinical specimens grew M. abscessus with a PFGE pattern that matched the pattern of the patient isolates. Cases of M. abscessus infection decreased to baseline after the hospital changed suppliers of mycobacterial media and cleaned the incubator. CONCLUSIONS: Although the source was never confirmed, our investigation suggests that this was a pseudo-outbreak of M. abscessus infection that resulted from contamination of mycobacterial cultures during incubation. Our findings emphasize the need for guidance on the disinfection of specimen incubators.

Evaluation of a macrofoam swab protocol for the recovery of Bacillus anthracis spores from a steel surface.

A protocol to recover Bacillus anthracis spores from a steel surface using macrofoam swabs was evaluated for its accuracy, precision, reproducibility, and limit of detection. Macrofoam swabs recovered 31.7 to 49.1% of spores from 10-cm2 steel surfaces with a < or =32.7% coefficient of variation in sampling precision and reproducibility for inocula of > or =38 spores.

Methicillin-resistant Staphylococcus aureus sepsis associated with the transfusion of contaminated platelets: a case report.

BACKGROUND: Platelet transfusion-associated sepsis is usually due to donor skin flora introduced into the unit during phlebotomy. An unusual case of a platelet component contaminated with methicillin-resistant Staphylococcus aureus (MRSA) is reported. CASE REPORT: A 54-year-old man, terminally ill with progressive non-Hodgkin's lymphoma, developed fever and hypotension during a platelet transfusion. He was receiving multiple antibiotics, including vancomycin. Blood cultures taken soon after transfusion were negative. An aliquot taken from the platelet pool grew MRSA at a count of 1.6 x 10(8) CFUs per mL. One of the individual bags constituting the pool showed MRSA at a count of 5.1 x 10(8) CFUs per mL. The patient died soon after the platelet transfusion. This case was reported to the FDA and submitted to the BaCon Study. The identity of the isolate and its methicillin resistance were confirmed by the CDC as part of the BaCon Study protocol. The source of contamination of the implicated unit could not be established with certainty. CONCLUSION: The emergence of antimicrobial-resistant organisms poses additional challenges for the diagnosis and treatment of transfusion-associated sepsis. Measures to prevent or intercept the transfusion of contaminated platelets should be developed.

Pontiac fever due to Legionella micdadei from a whirlpool spa: possible role of bacterial endotoxin.

During January 1998, a cluster of illnesses occurred among hotel guests in Wisconsin. Ill persons had been exposed to the hotel's whirlpool spa and swimming pool. Symptoms included headache, fever, chills, myalgia, shortness of breath, and fatigue. A diagnosis of Pontiac fever was made, based on serologic evidence of acute infection with Legionella micdadei. High concentrations of heterotrophic bacteria were recovered from the spa, despite apparently high disinfectant levels. L. micdadei was isolated from the swimming pool filter and water from the spa after heat enrichment but not from pools and spas at nearby hotels. Water from hotel pools and spas was tested to determine endotoxin levels; water from the spa of the implicated hotel contained the highest concentration of endotoxin (14,400 endotoxin units/mL). Additional studies are needed to determine the role of endotoxin from legionellae or other bacteria in the pathogenesis of Pontiac fever.

Infection control in hemodialysis units.

Infectious complications of hemodialysis include bacterial infections caused by contaminated water or equipment, other bacterial infections (including vascular access infections), and bloodborne viruses (primarily the hepatitis B and C viruses). Infections caused by contaminated water and equipment can be prevented by a well-designed water-treatment system, routine cleaning and disinfection of system components, and routine bacteriologic monitoring of dialysis water and dialysis fluid. Standard precautions with additional measures recommended specifically for dialysis centers will prevent transmission of bacteria and viruses from patient to patient. These precautions include routine use of gloves, handwashing, and cleaning and disinfection of the external surface of the dialysis machine and other environmental surfaces. In addition, preventing transmission of hepatitis B virus infection requires vaccination of susceptible patients and staff, avoiding dialyzer reuse, and use of a dedicated room, dialysis machine, and staff members when treating patients chronically infected with this virus.

Nosocomial outbreak of Microbacterium species bacteremia among cancer patients.

To date, only 6 sporadic Microbacterium species (formerly coryneform Centers for Disease Control and Prevention [CDC] groups A-4 and A-5) infections have been reported. The source, mode of transmission, morbidity, mortality, and potential for nosocomial transmission of Microbacterium species remain unknown. From 26 July through 14 August 1997, 8 episodes of coryneform CDC group A-5 symptomatic bacteremia occurred in 6 patients on the oncology ward at the Maine Medical Center. One patient died. All isolates were identified at CDC as Microbacterium species and had identical DNA banding patterns by pulsed-field gel electrophoresis. To assess risk factors for Microbacterium species infection, a retrospective cohort study was conducted. The presence of a central venous catheter was the strongest risk factor (6/6 vs. 22/48; relative risk, 3.2; P<.0001). This outbreak demonstrates significant Microbacterium species-associated morbidity and mortality in immunocompromised populations and confirms the potential for epidemic nosocomial transmission.

Serratia liquefaciens bloodstream infections from contamination of epoetin alfa at a hemodialysis center.

BACKGROUND: In a one month period, 10 Serratia liquefaciens bloodstream infections and 6 pyrogenic reactions occurred in outpatients at a hemodialysis center. METHODS: We performed a cohort study of all hemodialysis sessions on days that staff members reported S. liquefaciens bloodstream infections or pyrogenic reactions. We reviewed procedures and cultured samples of water, medications, soaps, and hand lotions and swabs from the hands of personnel. RESULTS: We analyzed 208 sessions involving 48 patients. In 12 sessions, patients had S. liquefaciens bloodstream infections, and in 8, patients had pyrogenic reactions without bloodstream infection. Sessions with infections or reactions were associated with higher median doses of epoetin alfa than the 188 other sessions (6500 vs. 4000 U, P=0.03) and were more common during afternoon or evening shifts than morning shifts (P=0.03). Sessions with infections or reactions were associated with doses of epoetin alfa of more than 4000 U (multivariate odds ratio, 4.0; 95 percent confidence interval, 1.3 to 12.3). A review of procedures revealed that preservative-free, single-use vials of epoetin alfa were punctured multiple times, and residual epoetin alfa from multiple vials was pooled and administered to patients. S. liquefaciens was isolated from pooled epoetin alfa, empty vials of epoetin alfa that had been pooled, antibacterial soap, and hand lotion. All the isolates were identical by pulsed-field gel electrophoresis. After the practice of pooling epoetin alfa was discontinued and the contaminated soap and lotion were replaced, no further S. liquefaciens bloodstream infections or pyrogenic reactions occurred at this hemodialysis facility. CONCLUSIONS: Puncturing single-use vials multiple times and pooling preservative-free epoetin alfa caused this outbreak of bloodstream infections in a hemodialysis unit. To prevent similar outbreaks, medical personnel should follow the manufacturer's guidelines for the use of preservative-free medications.

Control of vancomycin-resistant enterococcus in health care facilities in a region.

BACKGROUND: In late 1996, vancomycin-resistant enterococci were first detected in the Siouxland region of Iowa, Nebraska, and South Dakota. A task force was created, and in 1997 the assistance of the Centers for Disease Control and Prevention was sought in assessing the prevalence of vancomycin-resistant enterococci in the region's facilities and implementing recommendations for screening, infection control, and education at all 32 health care facilities in the region. METHODS: The infection-control intervention was evaluated in October 1998 and October 1999. We performed point-prevalence surveys, conducted a case-control study of gastrointestinal colonization with vancomycin-resistant enterococci, and compared infection-control practices and screening policies for vancomycin-resistant enterococci at the acute care and long-term care facilities in the Siouxland region. RESULTS: Perianal-swab samples were obtained from 1954 of 2196 eligible patients (89 percent) in 1998 and 1820 of 2049 eligible patients (89 percent) in 1999. The overall prevalence of vancomycin-resistant enterococci at 30 facilities that participated in all three years of the study decreased from 2.2 percent in 1997 to 1.4 percent in 1998 and to 0.5 percent in 1999 (P<0.001 by chi-square test for trend). The number of facilities that had had at least one patient with vancomycin-resistant enterococci declined from 15 in 1997 to 10 in 1998 to only 5 in 1999. At both acute care and long-term care facilities, the risk factors for colonization with vancomycin-resistant enterococci were prior hospitalization and treatment with antimicrobial agents. Most of the long-term care facilities screened for vancomycin-resistant enterococci (26 of 28 in 1998 [93 percent] and 23 of 25 in 1999 [92 percent]) and had infection-control policies to prevent the transmission of vancomycin-resistant enterococci (22 of 25 [88 percent] in 1999). All four acute care facilities had screening and infection-control policies for vancomycin-resistant enterococci in 1998 and 1999. CONCLUSIONS: An active infection-control intervention, which includes the obtaining of surveillance cultures and the isolation of infected patients, can reduce or eliminate the transmission of vancomycin-resistant enterococci in the health care facilities of a region.

Evaluation of a reporting system for bacterial contamination of blood components in the United States.

BACKGROUND: The transfusion of blood components contaminated with bacteria may have serious clinical consequences, but few data are available on the incidence of these events. A national effort to assess the frequency of blood component bacterial contamination associated with transfusion reaction (the BaCon Study) was initiated to better estimate their occurrence. STUDY DESIGN AND METHODS: Standard reporting criteria, data collection forms, and a standardized reporting protocol were developed in collaboration with the American Red Cross, AABB, and the Department of Defense. Episodes reported to the BaCon Study were compared with those reported to the FDA's national reporting systems to estimate the extent to which all serious reactions associated with bacterial contamination were captured. RESULTS: During the first 2 years, 38 episodes meeting study criteria were reported; 21 were laboratory-confirmed. The estimated proportion of episodes reported to the BaCon Study (i.e., completeness of coverage) was lower than that reported to the FDA during the same period (0.33 vs. 0.68), but the positive predictive value was higher (0.66 vs.0.28). CONCLUSION: Despite the complexity of obtaining reports from a large number of United States hospitals and transfusion centers, the feasibility and usefulness of the BaCon Study were shown. This study was the only national study in the United States to monitor adverse clinical events associated with bacterial contamination of blood components. By building on hospital-based reporting of transfusion-related adverse events, the BaCon Study serves as a model for the study of other complications associated with blood and blood components.

Transfusion-transmitted bacterial infection in the United States, 1998 through 2000.

BACKGROUND: Bacterial contamination of blood components can result in transfusion-transmitted infection, but the risk is not established. STUDY DESIGN AND METHODS: Suspected cases of transfusion-transmitted bacteremia were reported to the CDC by participating blood collection facilities and transfusion services affiliated with the American Red Cross, AABB, or Department of Defense blood programs from 1998 through 2000. A case was defined as any transfusion reaction meeting clinical criteria in which the same organism species was cultured from a blood component and from recipient blood, with the organism pair confirmed as identical by molecular typing. RESULTS: There were 34 cases and 9 deaths. The rate of transfusion-transmitted bacteremia (in events/million units) was 9.98 for single-donor platelets, 10.64 for pooled platelets, and 0.21 for RBC units; for fatal reactions, the rates were 1.94, 2.22, and 0.13, respectively. Patients at greatest risk for death received components containing gram-negative organisms (OR, 7.5; 95% CI, 1.3-64.2; p = 0.009). CONCLUSION: Bacterial contamination of blood is an important cause of transfusion-transmitted infection; infection risk from platelet transfusion is higher compared with that from RBCs, and, overall, the risk of infection from bacterial contamination now may exceed that from viral agents. Recipients of components containing gram-negative organisms are at highest risk for transfusion-related death. The results of this study may help direct efforts to improve transfusion-related patient safety.

Transfusion-related sepsis due to Serratia liquefaciens in the United States.

BACKGROUND: Severe, often fatal, transfusion reactions due to bacterial contamination of blood components continue to occur. Serratia liquefaciens, an unusual human pathogen, is a recently recognized potential cause of transfusion-related sepsis. CASE REPORTS: Five episodes of transfusion-related sepsis and endotoxic shock due to S. liquefaciens were reported to the CDC from July 1992 through January 1999. One episode has been described. The remaining four, all fatal, are described here: three associated with RBC transfusion and one associated with transfusion of platelets. In each instance, the source of contamination could not be found. The implicated units tended to be older (mean RBC age 28 days), and visual discoloration was noted in each RBC unit, although usually in retrospect. CONCLUSION: S. liquefaciens is an increasingly recognized cause of transfusion-related sepsis and is associated with a high mortality rate. S. liquefaciens can contaminate both RBCs and platelets, but the mechanism(s) of contamination remain unknown. Increased attention to pretransfusion visual inspection may avert the transfusion of some S. liquefaciens-contaminated RBC units. However, more sensitive rapid diagnostic tests are needed to further reduce the risk of transfusion-related sepsis and endotoxic shock.

Enterobacter cloacae bloodstream infections traced to contaminated human albumin.

In August 1996, a patient in Kansas developed an Enterobacter cloacae bloodstream infection (BSI) shortly after receiving Albuminar, a brand of human albumin. Albuminar contamination was suspected. A case-control study of patients with primary gram-negative bacterial BSIs showed that patients with E. cloacae BSIs were significantly more likely than patients with non-E. cloacae gram-negative BSIs to have received Albuminar within 3 days of developing their BSIs (3 of 5 vs. 0 of 9; OR, undefined; P=.03). The E. cloacae isolate from the Kansas patient was found by pulsed-field gel electrophoresis to be identical to the isolate from the patient's Albuminar vial, to isolates from 2 previously unopened Albuminar vials, and to an isolate from a Wisconsin patient who had received Albuminar. A worldwide recall of approximately 116,000 Albuminar vials took place. This multistate outbreak was detected because of clinical astuteness and prompt reporting. Combined epidemiological and laboratory approaches are valuable when investigating potentially contaminated blood components and plasma derivatives.

An outbreak of gram-negative bacteremia in hemodialysis patients traced to hemodialysis machine waste drain ports.

OBJECTIVE: To investigate an outbreak of gram-negative bacteremias at a hemodialysis center (December 1, 1996-January 31, 1997). DESIGN: Retrospective cohort study. Reviewed infection control practices and maintenance and disinfection procedures for the water system and dialysis machines. Performed cultures of the water and dialysis machines, including the waste-handling option (WHO), a drain port designed to dispose of saline used to flush the dialyzer before patient use. Compared isolates by pulsed-field gel electrophoresis. SETTING: A hemodialysis center in Maryland. RESULTS: 94 patients received dialysis on 27 machines; 10 (11%) of the patients had gram-negative bacteremias. Pathogens causing these infections were Enterobacter cloacae (n = 6), Pseudomonas aeruginosa (n = 4), and Escherichia coli (n = 2); two patients had polymicrobial bacteremia. Factors associated with development of gram-negative bacteremias were receiving dialysis via a central venous catheter (CVC) rather than via an arterio-venous shunt (all 10 infected patients had CVCs compared to 31 of 84 uninfected patients, relative risk [RR] undefined; P<.001) or dialysis on any of three particular dialysis machines (7 of 10 infected patients were exposed to the three machines compared to 20 of 84 uninfected patients, RR = 5.8; P = .005). E cloacae, P aeruginosa, or both organisms were grown from cultures obtained from several dialysis machines. WHO valves, which prevent backflow from the drain to dialysis bloodlines, were faulty in 8 (31%) of 26 machines, including 2 of 3 machines epidemiologically linked to case-patients. Pulsed-field gel electrophoresis patterns of available dialysis machine and patient E cloacae isolates were identical. CONCLUSIONS: Our study suggests that WHO ports with incompetent valves and resultant backflow were a source of cross-contamination of dialysis bloodlines and patients' CVCs. Replacement of faulty WHO valves and enhanced disinfection of dialysis machines terminated the outbreak.