Sylvia Garcia-Houchins

Severe Eczema Vaccinatum in a Household Contact of a Smallpox Vaccinee

BACKGROUND We report the first confirmed case of eczema vaccinatum in the United States related to smallpox vaccination since routine vaccination was discontinued in 1972. A 28-month-old child with refractory atopic dermatitis developed eczema vaccinatum after exposure to his father, a member of the US military who had recently received smallpox vaccine. The father had a history of inactive eczema but reportedly reacted normally to the vaccine. The childs mother also developed contact vaccinia infection. METHODS Treatment of the child included vaccinia immune globulin administered intravenously, used for the first time in a pediatric patient; cidofovir, never previously used for human vaccinia infection; and ST-246, an investigational agent being studied for the treatment of orthopoxvirus infection. Serological response to vaccinia virus and viral DNA levels, correlated with clinical events, were utilized to monitor the course of disease and to guide therapy. Burn patient-type management was required, including skin grafts. RESULTS The child was discharged from the hospital after 48 days and has recovered with no apparent systemic sequelae or significant scarring. CONCLUSION This case illustrates the need for careful screening prior to administration of smallpox vaccine and awareness by clinicians of the ongoing vaccination program and the potential risk for severe adverse events related to vaccinia virus.

Management of outbreaks of methicillin-resistant Staphylococcus aureus infection in the neonatal intensive care unit : A consensus statement

OBJECTIVE In 2002, the Chicago Department of Public Health (CDPH; Chicago, Illinois) convened the Chicago-Area Neonatal MRSA Working Group (CANMWG) to discuss and compare approaches aimed at control of methicillin-resistant Staphylococcus aureus (MRSA) in neonatal intensive care units (NICUs). To better understand these issues on a regional level, the CDPH and the Evanston Department of Health and Human Services (EDHHS; Evanston, Illinois) began an investigation. DESIGN Survey to collect demographic, clinical, microbiologic, and epidemiologic data on individual cases and clusters of MRSA infection; an additional survey collected data on infection control practices. SETTING Level III NICUs at Chicago-area hospitals. PARTICIPANTS Neonates and healthcare workers associated with the level III NICUs. METHODS From June 2001 through September 2002, the participating hospitals reported all clusters of MRSA infection in their respective level III NICUs to the CDPH and the EDHHS. RESULTS Thirteen clusters of MRSA infection were detected in level III NICUs, and 149 MRSA-positive infants were reported. Infection control surveys showed that hospitals took different approaches for controlling MRSA colonization and infection in NICUs. CONCLUSION The CANMWG developed recommendations for the prevention and control of MRSA colonization and infection in the NICU and agreed that recommendations should expand to include future data generated by further studies. Continuing partnerships between hospital infection control personnel and public health professionals will be crucial in honing appropriate guidelines for effective approaches to the management and control of MRSA colonization and infection in NICUs.

Predictive factors for the development of central line-associated bloodstream infection due to gram-negative bacteria in intensive care unit patients after surgery.

OBJECTIVES To examine the relative proportions of central line-associated bloodstream infection (BSI) due to gram-negative bacteria and due to gram-positive bacteria among patients who had undergone surgery and patients who had not. The study also evaluated clinical predictive factors and unadjusted outcomes associated with central line-associated BSI caused by gram-negative bacteria in the postoperative period. DESIGN Observational, case-control study based on a retrospective review of medical records. SETTING University of Chicago Medical Center, a 500-bed tertiary care center located on Chicagos south side. PATIENTS Adult intensive care unit (ICU) patients who developed central line-associated BSI. RESULTS There were a total of 142 adult patients who met the Centers for Disease Control and Prevention National Nosocomial Infection Surveillance System definition for central line-associated BSI. Of those, 66 patients (46.5%) had infections due to gram-positive bacteria, 49 patients (34.5%) had infections due to gram-negative bacteria, 23 patients (16.2%) had infections due to yeast, and 4 patients (2.8%) had mixed infections. Patients who underwent surgery were more likely to develop central line-associated BSI due to gram-negative bacteria within 28 days of the surgery, compared with patients who had not had surgery recently (57.6% vs 27.3%; P= .002). On multivariable logistic regression analysis, diabetes mellitus (adjusted odds ratio [OR], 4.6 [95% CI, 1.2-18.1]; P= .03) and the presence of hypotension at the time of the first blood culture positive for a pathogen (adjusted OR, 9.8 [95% CI, 2.5-39.1]; P= .001) were found to be independently predictive of central line-associated BSI caused by gram-negative bacteria. Unadjusted outcomes were not different in the group with BSI due to gram-negative pathogens, compared to the group with BSI due to gram-positive pathogens. CONCLUSIONS Clinicians caring for critically ill patients after surgery should be especially concerned about the possibility of central line-associated BSI caused by gram-negative pathogens. The presence of diabetes and hypotension appear to be significant associated factors.

An Outbreak of Fatal Fluoride Intoxication in a Long-Term Hemodialysis Unit

Long-term hemodialysis is the most common treatment for end-stage renal disease in the United States and was administered to more than 155 000 patients in 1991 [1]. Technologic developments in dialyzer membranes, dialysis machines, and vascular access have made hemodialysis routine, but the procedure remains potentially hazardous because of mechanical malfunctions and human error [2]. Serious adverse reactions have resulted, particularly from microbiological or chemical contamination of hemodialyzers and dialysate solutions [2-7]. Municipal water used to prepare dialysate must be purified to ensure that no contaminants remain that would be toxic to patients receiving dialysis. Reverse osmosis is the most common procedure to remove ions, but deionization systems, alone or after reverse osmosis, were used by nearly one half of the hemodialysis centers in the United States in 1991 [1]. Paradoxically, these deionization systems pose an additional hazard. When their ion exchange resin becomes exhausted, toxic ions previously removed from municipal water and bound to the resin may be displaced into the effluent stream of purified water [5, 6]. Johnson and Taves [8] found that high concentrations of fluoride could be released in this manner into effluent, but no cases of acute fluoride intoxication attributable to this mechanism have been reported. We recently investigated in a hemodialysis unit an outbreak of acute illness and death caused by fluoride intoxication. We describe the epidemiologic characteristics of the outbreak and the pattern of deionization system use that resulted in massive fluoride efflux from an exhausted resin. The Outbreak On 16 July 1993, several patients treated at a long-term hemodialysis unit became ill during or soon after hemodialysis. The predominant symptoms were severe pruritus, headache, nausea, and chest or back pain. One patient had cardiac arrest immediately after completion of dialysis. Patients continued to receive dialysis treatment until that afternoon, when the unit was notified that two other patients had had cardiac arrests after leaving the unit. Dialysis treatments were stopped during the third shift of patients, and patients who had received hemodialysis on 16 July were brought to the University of Chicago Hospital for evaluation. Those who had any symptoms were admitted to the hospital, and patients whose scheduled treatment had been interrupted resumed dialysis at the hospitals acute care dialysis unit. An investigation was then initiated. Methods Clinical and Epidemiologic Characteristics of the Patients We interviewed patients who received long-term hemodialysis treatment in the unit and reviewed their records to identify symptoms during the period 26 April to 16 July 1993, when a temporary water purification system was used. We considered that patients had severe hemodialysis-associated illness if within 5 hours after the start of dialysis either severe pruritus developed or cardiac arrest ensued, or if at least three of the following symptoms developed: burning or feverish feeling; headache; nausea or vomiting; syncope or near syncope; pain in the chest, back, or abdomen; or diarrhea. We reviewed medical and dialysis unit records to determine patient age, sex, primary underlying illness, results of physical examination and clinical laboratory tests, number of years of long-term hemodialysis, duration of the hemodialysis session on 15 or 16 July, hemodialysis blood flow rate, type of dialyzer, and dialyzer reuse. We considered that patients had cardiac disease if they had coronary artery disease, cardiomyopathy, valvular heart disease, or clinically significant electrocardiographic abnormalities such as bundle-branch block. For statistical analysis, we compared each continuous variable using the t-test and the Wilcoxon test, and proportions were compared using the Fisher exact test [9]. Dialysis Unit Design and Water Supply We surveyed the municipal water supply, dialysis water purification systems, types of dialyzers and dialysis machines, dialysate preparation, and dialyzer reprocessing procedures. We also reviewed records of daily municipal water treatment and periodic chemical analyses by the City of Chicago Department of Water during 7 June to 16 July 1993. Sample Collection and Analysis Blood specimens were collected on 16 July from all surviving patients who had had hemodialysis treatment that day. Complete blood count and routine blood chemistry testing were done. A portion of each sample was stored at 70C and later assayed for fluoride. Samples of purified water used for dialysate preparation were collected on 16 July 1993 for analysis of 18 chemicals for which maximum allowable levels were established by the Association for the Advancement of Medical Instrumentation [10]. Samples of municipal water, purified water used to prepare dialysate, acid concentrate, bicarbonate concentrate, and bicarbonate dialysate also were collected on 16 July and assayed for fluoride concentration using an ion-selective electrode system (Orion Research, Cambridge, Massachusetts) [11]. Additional samples of purified water from each of the two sets of deionization tanks in the room (room 1) where sick patients had received hemodialysis treatment were collected on 17 July after approximately 1000 L of water had flowed through the systems when the dialysis machines were tested. These samples and dialysate collected from room 1 on 16 July were assayed by the Illinois Department of Public Health for fluoride and for toxic organic compounds by gas chromatography-mass spectrometry and by ultraviolet spectrometry. Postmortem serum specimens were obtained and assayed for fluoride by the Cook County Medical Examiners Office. Model Deionization System To confirm that sustained high levels of fluoride in effluent from the deionization system in the dialysis unit could have been released by operating the system after the resin was exhausted, a laboratory model of the system was constructed. An activated carbon tank and four newly regenerated deionization tanks were supplied by the water treatment contractor who maintained the system in the dialysis unit. The four tanks were arranged in series as follows: first, a cation resin tank containing sulfonated polystyrene (Amberlite IR-120 Plus, Rohm and Haas, Philadelphia, Pennsylvania) in position 1; next, an anion resin tank containing a type II quaternary ammonium resin (Amberlite IRA-410) in position 2; then two mixed-bed tanks containing both cation and anion resins in positions 3 and 4. This system was used to treat 27 500 L of municipal water, a volume estimated to be the same as that which flowed through each of the two sets of deionization tanks in room 1 from 26 April to 7 June 1993. A second deionization system was then constructed with newly regenerated tanks in positions 1, 2, and 4; the mixed-bed tank from position 4 in the first deionization system was moved into position 3, as had been done in the dialysis unit. The second deionization system was operated beyond exhaustion of the resins to simulate use from 7 June to 16 July 1993. During operation of the two model deionization systems, effluent was collected to measure fluoride concentration and resistivity, which decreases as electrolyte concentration increases. Results Clinical and Epidemiologic Characteristics of the Patients At the time of the outbreak, 56 patients were receiving long-term, high-flux hemodialysis. One half of the patients were treated on Monday, Wednesday, and Friday, and the other half were treated on Tuesday, Thursday, and Saturday. Twenty-one patients received at least a portion of their scheduled dialysis on 16 July before treatments were stopped. Nine of the 21 patients treated on 16 July and 3 of the 25 patients treated on 15 July were classified as cases. Review of dialysis unit records for the previous 12 weeks identified only 1 additional patient who met the case definition. That patient, who had a cardiac arrest on 9 June, was not considered to be part of this outbreak and thus we did not include him as a case-patient. Table 1 summarizes the characteristics of both the 12 patients classified as case-patients and the 20 patients not considered cases who were treated during the same shifts. Symptoms other than cardiac arrest began 1 to 3 hours after the start of hemodialysis in all cases and resolved by the next morning. Case-patients who reported pruritus described it as the most severe they had ever experienced. Diphenhydramine hydrochloride was taken by 5 patients, none of whom noted any relief. Pruritus lasted more than 6 hours in the surviving patients who became ill on 16 July and less than 3 hours in the three patients who became ill on 15 July. Table 1. Demographic Characteristics and Clinical Features of Patients Receiving Long-Term Hemodialysis Cardiac arrests occurred 4 to 6.5 hours after hemodialysis began. Antecedent symptoms were pruritus, vomiting, and/or chest pain in two patients and leg pain in the third. Emergency medical care records showed fatal ventricular fibrillation in all three patients; one was restored briefly to sinus rhythm by electrical cardioversion. All three had preexisting cardiac abnormalities: left bundle-branch block, right bundle-branch block and coronary artery disease, or mitral stenosis with atrial fibrillation. All six surviving patients who became ill on 16 July were hospitalized that evening. None had new abnormal findings on physical examination or complete blood count, and none had hyperkalemia. Three patients had low serum calcium concentrations of 7.8 to 8.3 mg/dL (1.95 to 2.54 mmol/L). Patients in the dialysis unit received high-flux dialysis in two treatment rooms using individual self-proportioning, volumetrically controlled ultrafiltration machines (COBE Centrysystem 3, COBE Laboratories, Lakewood, Colorado). The 12 patients who became ill received dialysis treatment for a mean of 2.8 0.7 hours (ra

An Outbreak of Gram-Negative Bacteremia Traced to Contaminated O-Rings in Reprocessed Dialyzers

Reprocessing of hemodialyzers has become a common practice in the United States because of decreased costs, improved biocompatibility, and fewer patient symptoms [1-3]. Reuse generally has been safe, but pyrogenic reactions and bacteremia occasionally have occurred [4-11]. These problems have been attributed to improper disinfection procedures [4, 7, 9] or inadequate potency of the solution used to disinfect the dialyzer [5-7, 9]. Treated water used to prepare dialysate and rinse dialyzers has been implicated as the reservoir for organisms causing bacteremia [4, 9, 11], but the exact means by which bacteria from the treated water reach the bloodstream of patients has not been elucidated. We investigated a cluster of cases of gram-negative bacteremia in patients receiving long-term hemodialysis at our institution. Using epidemiologic and laboratory studies, we identified the mechanism by which bacteria were transmitted from treated water to the bloodstream of patients receiving hemodialysis treatment. Methods Hemodialysis Unit The outpatient hemodialysis unit at the University of Chicago Hospital was opened in July 1985 in a building separate from the hospital. At the time of the outbreak, approximately 130 patients were receiving long-term hemodialysis treatment there. The unit operated three shifts per day, 6 days per week, and administered approximately 390 hemodialysis treatments per week. In September 1987, the center introduced high-flux dialysis, and in October 1987 the unit began a program of dialyzer reuse. Reprocessing was done by an automated procedure (Renatron; Minntech, Minneapolis, Minnesota) using a hydrogen peroxide-peracetic acid germicide (Renalin, Minntech). The long-term hemodialysis unit has two rooms for patient treatment and a separate room for the water treatment system, supplies, and dialyzer reprocessing. The main treatment room contains 16 stations, and the other treatment room (annex) contains 3 stations. The use of high-flux dialysis increased dramatically during March 1988, so that at the time of the investigation in July 1988, approximately 50% of all patients at the center were receiving high-flux dialysis. Recovery of Pseudomonas cepacia from blood culture specimens taken during dialysis on 30 June 1988 from 2 patients receiving long-term hemodialysis prompted an investigation that continued from July 1988 to April 1989. Case Definition and Case Detection A case was defined as an episode of primary gram-negative bacteremia occurring in a patient receiving long-term hemodialysis. To detect cases, results of all blood culture specimens from patients receiving long-term hemodialysis were reviewed retrospectively for the period 1 July 1987 to 30 June 1988 and then prospectively through April 1989. Blood Cultures Specimens for blood culture were obtained during hemodialysis from the venous return port after it was wiped with an iodophor antiseptic and then with 70% alcohol. Specimens were inoculated into an enrichment medium (Bactec, NR660; Becton-Dickinson Diagnostic Instrument Systems, Towson, Maryland). All organisms isolated were identified by an automated method (AutoMicrobic Systems; Vitek, Hazelwood, Missouri), confirmed by conventional biochemical methods, and tested for susceptibility to antimicrobial agents using a broth microdilution method. Matched-Pair Study We did a casecontrol study to identify risk factors for the development of primary gram-negative bacteremia. For each case, a matched control of the same sex and closest age was selected from among patients having outpatient hemodialysis on the same day who did not have signs or symptoms of gram-negative bacteremia. Medical records were reviewed to identify underlying renal disease; years on long-term dialysis; type of dialyzer (high-flux or conventional); type of vascular access; dialysis shift, station number, and location; dialysis machine; number of times dialyzer had been reused; dialyzer reprocessing technician; and recent antibiotic use. Data were analyzed using the McNemar chi-square test and the Wilcoxon signed-rank test. Evaluation of the Hemodialysis Unit and Hemodialyzers Techniques used to disinfect water-distribution lines and hemodialysis machines, to reprocess dialyzers, and to dialyze patients were observed to determine compliance with written procedures. The results of cultures routinely done each month to monitor treated water were reviewed, and, during the first 3 months of the investigation, additional 100-mL samples of treated water were cultured weekly from seven sites throughout the water-distribution system. Total bacterial counts were determined using a standard membrane filter technique [12]. On 7 July 1988 and 18 October 1988, cultures were taken of moist environmental surfaces and of antiseptics and solutions used in the dialysis unit for hemodialysis and dialyzer reprocessing. Serial volumes (1, 0.1, and 0.01 mL) of solution were plated on blood agar and incubated for 48 hours at 35 C, and growth was assessed quantitatively. Swab samples were plated on blood agar and assessed semi-quantitatively. All isolated organisms were identified using a commercially available kit (API test-strips; Analylab Products, Inc., Plainview, New York) or by conventional biochemical methods. When available, hemodialyzers (associated with patients who had bacteremia) were examined and cultured. Dialysis and blood pathway fluids were cultured using standard membrane filter techniques and were assayed for the presence of Renalin using Renalin residual test strips (Renal Systems, Inc.; Minneapolis, Minnesota). Screw-top headers (when present) were removed, and the fiber-bundle ends and header O-rings were cultured by impression onto blood agar. During 7 July to 6 September, 47 dialyzers used in patients without bacteremia were similarly cultured and assayed for Renalin concentration. O-Ring Contamination To determine whether O-rings were adequately decontaminated during reprocessing, O-rings from Hemoflow F-80 hemodialyzers (Fresenius AG; Bad Homburg, Germany) Figure 1 were deliberately contaminated by being dipped in a bacterial suspension and were then replaced in dialyzers that were reprocessed. Strains of bacteria used in these experiments were the isolates of P. cepacia, Xanthomonas maltophilia, Citrobacter freundii, Enterobacter cloacae, and Acinetobacter calcoaceticus var. anitratus from patients receiving hemodialysis who had gram-negative bacteremia. Bacterial concentrations ranged from 102 to 105 colony-forming units (CFU)/mL. After the dialyzers had been disinfected with Renalin and stored for 48 hours, sterile saline was flushed through the blood and dialysis compartments and was then cultured quantitatively by plating 0.1-, 1.0-, and 10-mL aliquots onto blood agar. Also, O-rings were removed and cultured by impression onto blood agar. Growth was assessed semi-quantitatively at 48 hours as light when a faint or partial outline of a ring was visible, moderate when a complete circle was present with bleeding onto the surrounding agar, and heavy when a lawn of growth was present. Dialyzers showing persistent bacterial contamination after initial disinfection were processed a second time using the standard method. Several dialyzers with positive cultures after a second attempted disinfection were disinfected a third time with the additional step of removing the O-rings, dipping them in Renalin, and replacing them in the header before reuse. Figure 1. Schematic representation of the Hemoflow F-80 dialyzer. Simulated Dialysis Simulated hemodialysis was done after F-80 dialyzer O-rings were contaminated by dipping them in a suspension of 104 to 105 CFU/mL of bacteria. Dialyzers were reprocessed and stored at room temperature for 48 hours. To simulate dialysis, each dialyzer was connected to a dialysis machine, and 800 mL of sterile saline was circulated through the blood compartment, whereas 600 mL of bicarbonate solution was circulated through the dialysis compartment. This simulation was continued for approximately 20 minutes for each dialyzer. The saline circulating through the blood pathway was cultured, the dialyzers were then disconnected, and the O-rings were cultured. Next, these dialyzers were reprocessed with the additional step of removing the O-ring and dipping it in Renalin before automated reprocessed. The O-rings were replaced, and the dialyzer was reprocessed by the automated method. After storage at room temperature for 48 hours, the dialyzers again were used for simulated dialysis, and cultures were repeated. Results Description of Cases During January to October 1988, 12 episodes of primary gram-negative bacteremia were identified in 11 patients receiving long-term hemodialysis (Table 1). One episode was caused by two different organisms, and the pathogens in the 12 episodes were P. cepacia (6 episodes), X. maltophilia (4 episodes), C. freundii (1 episode), Acinetobacter calcoaceticus var. anitratus (1 episode), and E. cloacae (1 episode). During the course of the outbreak, gram-negative bacteremia occurred at a rate of about 0.77 episodes per 1000 hemodialysis sessions. Table 1. Characteristics of Patients Receiving Long-Term Hemodialysis in Whom Primary Gram-Negative Bacteremia Developed The most common clinical manifestations of bacteremia were chills (11 episodes) and temperature greater than 37.5 C (8 episodes). In 11 episodes, symptoms began about 30 minutes to 3 hours after the start of treatment. In the remaining episode, chills began shortly after the patient had completed treatment and left the dialysis unit. Intravenous antibiotic treatment was administered for 11 episodes, and 3 episodes required that the patient be admitted to the hospital. All of the patients recovered, including one who received no treatment for X. maltophilia bacteremia. One patient had bacteremia first with C. freundii and then 6 weeks later with P. cepacia. Pseudomonas cepacia bacteremia was documented

Staphylococcus aureus Bacteremia at 5 US Academic Medical Centers, 2008–2011: Significant Geographic Variation in Community-Onset Infections

BACKGROUND The incidence of community-onset (CO) methicillin-resistant Staphylococcus aureus (MRSA) bacteremia rose from the late 1990s through the 2000s. However, hospital-onset (HO) MRSA rates have recently declined in the United States and Europe. METHODS Data were abstracted from infection prevention databases between 1 January 2008 and 31 December 2011 at 5 US academic medical centers to determine the number of single-patient blood cultures positive for MRSA and methicillin-susceptible S. aureus (MSSA) per calendar year, stratified into CO and HO infections. RESULTS Across the 5 centers, 4171 episodes of bacteremia were identified. Center A (Los Angeles, California) experienced a significant decline in CO-MRSA bacteremia rates (from a peak in 2009 of 0.42 to 0.18 per 1000 patient-days in 2011 [P = .005]), whereas CO-MSSA rates remained stable. Centers B (San Francisco, California), D (Chicago, Illinois), and E (Raleigh-Durham, North Carolina) experienced a stable incidence of CO-MRSA and CO-MSSA bacteremia. In contrast, at center C (New York, New York), the incidence of CO-MRSA increased >3-fold (from 0.11 to 0.34 cases per 1000 patient-days [P < .001]). At most of the sites, HO-MRSA decreased and HO-MSSA rates were stable. USA300 accounted for 52% (104/202) of genotyped MRSA isolates overall, but this varied by center, ranging from 35% to 80%. CONCLUSIONS CO-MRSA rates and the contribution of USA300 MRSA varied dramatically across diverse geographical areas in the United States. Enhanced infection control efforts are unlikely to account for such variation in CO infection rates. Bioecological and clinical explanations for geographical differences in CO-MRSA bacteremia rates merit further study.

Clostridium difficile outbreak strain BI is highly endemic in Chicago area hospitals.

OBJECTIVE Describe the clinical and molecular epidemiology of incident Clostridium difficile infection (CDI) cases in Chicago area acute healthcare facilities (HCFs). DESIGN AND SETTING Laboratory, clinical, and epidemiologic information was collected for patients with incident CDI who were admitted to acute HCFs in February 2009. Stool cultures and restriction endonuclease analysis typing of the recovered C. difficile isolates was performed. PATIENTS Two hundred sixty-three patients from 25 acute HCFs. RESULTS Acute HCF rates ranged from 2 to 7 patients with CDI per 10,000 patient-days. The crude mortality rate was 8%, with 20 deaths occurring in patients with CDI. Forty-two (16%) patients had complications from CDI, including 4 patients who required partial, subtotal, or total colectomy, 3 of whom died. C. difficile was isolated and typed from 129 of 178 available stool specimens. The BI strain was identified in 79 (61%) isolates. Of patients discharged to long-term care who had their isolate typed, 36 (67%) had BI-associated CDI. CONCLUSIONS Severe disease was common and crude mortality was substantial among patients with CDI in Chicago area acute HCFs in February 2009. The outbreak-associated BI strain was the predominant endemic strain identified, accounting for nearly two-thirds of cases. Focal HCF outbreaks were not reported, despite the presence of the BI strain. Transfer of patients between acute and long-term HCFs may have contributed to the high incidence of BI cases in this investigation.

Bacterial colonization and succession in a newly opened hospital

Patients share their microbiota with their rooms and with nursing staff, and this shapes the microbial ecology of the hospital environment. A new hospital teems with life Lax et al. conducted a yearlong survey of the bacterial diversity associated with the patients, staff, and built surfaces in a newly opened hospital. They found that the bacterial communities on patient skin strongly resembled those found in their rooms. The authors demonstrated that the patient skin microbial communities were shaped by a diversity of clinical and environmental factors during hospitalization. They found little effect of intravenous or oral antibiotic treatment on the skin microbiota of patients. The microorganisms that inhabit hospitals may influence patient recovery and outcome, although the complexity and diversity of these bacterial communities can confound our ability to focus on potential pathogens in isolation. To develop a community-level understanding of how microorganisms colonize and move through the hospital environment, we characterized the bacterial dynamics among hospital surfaces, patients, and staff over the course of 1 year as a new hospital became operational. The bacteria in patient rooms, particularly on bedrails, consistently resembled the skin microbiota of the patient occupying the room. Bacterial communities on patients and room surfaces became increasingly similar over the course of a patient’s stay. Temporal correlations in community structure demonstrated that patients initially acquired room-associated taxa that predated their stay but that their own microbial signatures began to influence the room community structure over time. The α- and β-diversity of patient skin samples were only weakly or nonsignificantly associated with clinical factors such as chemotherapy, antibiotic usage, and surgical recovery, and no factor except for ambulatory status affected microbial similarity between the microbiotas of a patient and their room. Metagenomic analyses revealed that genes conferring antimicrobial resistance were consistently more abundant on room surfaces than on the skin of the patients inhabiting those rooms. In addition, persistent unique genotypes of Staphylococcus and Propionibacterium were identified. Dynamic Bayesian network analysis suggested that hospital staff were more likely to be a source of bacteria on the skin of patients than the reverse but that there were no universal patterns of transmission across patient rooms.

An Outbreak of Bloodstream Infections Arising from Hemodialysis Equipment

An outbreak of 29 cases of bloodstream infection by 16 pathogens occurred during 8 months at two chronic hemodialysis centers. Consequences included 21 hospital admissions and removal of 23 dialysis catheters. An epidemiologic investigation comparing case-patients with uninfected controls showed that risk was significantly (P < .05) associated with having a catheter for vascular access; receiving treatment on a Monday, Wednesday, Friday schedule; and receiving treatment on one heavily contaminated dialysis machine. Culture studies and mock trials showed that bloodstream pathogens were present in a recently installed, commercially marketed attachment for disposal of spent priming saline and could enter blood line tubing directly or indirectly during dialyzer priming and tubing assembly. The outbreak was halted by measures directed at the attachment. Investigation of this problem demonstrated that microbial overgrowth in the attachment caused bloodstream infections and underscores the importance of microbiologic considerations in the design and use of hemodialysis equipment.

Influenza Among Afebrile and Vaccinated Healthcare Workers

Among healthcare workers with influenza, half were afebrile. There was no significant difference in the rate of fever among individuals with influenza who had been previously vaccinated compared with those who had not been vaccinated (55% vs 39%; P = .33).