The role of drinking water in the transmission of antimicrobial-resistant E. coli.

To determine whether drinking water contaminated with antimicrobial-resistant E. coli is associated with the carriage of resistant E. coli, selected households sending water samples to Ontario and Alberta laboratories in 2005-2006 were asked to participate in a cross-sectional study. Household members aged ≥12 years were asked to complete a questionnaire and to submit a rectal swab. In 878 individuals, 41% carried a resistant strain of E. coli and 28% carried a multidrug-resistant strain. The risk of carriage of resistant E. coli was 1·26 times higher for users of water contaminated with resistant E. coli. Other risk factors included international travel [prevalence ratio (PR) 1·33], having a child in nappies (PR 1·33), being male (PR 1·33), and frequent handling of raw red meats (PR 1·10). Protecting private water sources (e.g. by improving systems to test and treat them) may help slow the emergence of antimicrobial resistance in E. coli.

Carbapenemase-producing Enterobacterales in hospital drains in Southern Ontario, Canada.

BACKGROUND: Hospital drains may be an important reservoir for carbapenemase-producing Enterobacterales (CPE). AIM: To determine prevalence of CPE in hospital drains exposed to inpatients with CPE, relatedness of drain and patient CPE, and risk factors for drain contamination. METHODS: Sink and shower drains in patient rooms and communal shower rooms exposed to 310 inpatients with CPE colonization/infection were cultured at 10 hospitals. Using short- and long-read whole-genome sequencing, inpatient and corresponding drain CPE were compared. Risk factors for drain contamination were assessed using multi-level modelling. FINDINGS: Of 1209 exposed patient room and communal shower room drains, 53 (4%) yielded 62 CPE isolates in seven (70%) hospitals. Of 49 CPE isolates in patient room drains, four (8%) were linked to prior room occupants. Linked drain/room occupant pairs included Citrobacter freundii ST18 isolates separated by eight single nucleotide variants (SNVs), related blaKPC-containing IncN3-type plasmids (different species), related blaKPC-3-containing IncN-type plasmids (different species), and related blaOXA-48-containing IncL/M-type plasmids (different species). In one hospital, drain isolates from eight rooms on two units were Enterobacter hormaechei separated by 0-6 SNVs. Shower drains were more likely to be CPE-contaminated than hand hygiene (odds ratio: 3.45; 95% confidence interval: 1.66-7.16) or patient-use (13.0; 4.29-39.1) sink drains. Hand hygiene sink drains were more likely to be CPE-contaminated than patient-use sink drains (3.75; 1.17-12.0). CONCLUSION: Drain contamination was uncommon but widely dispersed. Drain CPE unrelated to patient exposure suggests contamination by undetected colonized patients or retrograde (drain-to-drain) contamination. Drain types had different contamination risks.

The buffering capacity of the internal phase of thylakoids and the magnitude of the pH changes inside under flashing light.

The buffering capacity inside thylakoids is determined and the magnitude of flash-induced pH changes inside is calibrated in the pH range from 6.4 to 8.1. The work is based on flash-induced absorption changes of neutral red in a chloroplast suspension in which the outer phase is strongly buffered by bovine serum albumin. It is shown that neutral red is bound inside thylakoids. The binding can be described by a simple isotherm with an apparent Km = 4 microM and satruation at 1 neutral red per 17 chlorophylls. The apparent pK of neutral red is shifted from 6.6 in solution to 7.25 when bound inside. It is demonstrated that neutral red is a clean indicator of pH changes inside, i.e. when properly used it shows no response to other events. Although bound it reports pH changes which occur in the internal osmolar (aqueous) volume of thylakoids. This is obvious from the influence of chemically very different buffers on the magnitude of the absorption changes of neutral red. These act in a manner proportional to their calculated buffering capacity in aqueous solution. The intrinsic buffering capacity of the internal phase is determined with the aid of these buffers, at pH 7.2 it is between 0.8 and 1 mM (at 60 mosM). The absence of large variations in the buffering capacity in the range from pH 6.4 to 8.1 suggests that proteinaceous groups are involved in addition to the lipids which may dominate the buffering capacity at lower pH. The magnitude of the internal pH change is arrpox. 0.6 (at pH 7.3) under stimulation of both photosystems with a short xenon flash of light.

Incorporating variations in the quality of individual randomized trials into meta-analysis.

Meta-analysis is a method of synthesizing evidence from multiple sources. It has been increasingly applied to combine results from randomized trials of therapeutic strategies. Unfortunately there is often variation in the quality of the trials that are included in meta-analyses, limiting the value of combining the results in an overview. This variation in quality can lead to both bias and reduction in precision of the estimate of the therapy's effectiveness. There are a number of methods for quantifying the quality of trials including the detailed Chalmers system and simple scales. The nature of the relationship between these quality scores and the true estimate of effectiveness is unknown at this time. We discuss four methods of incorporating quality into meta-analysis: threshold score as inclusion/exclusion criterion, use of quality score as a weight in statistical pooling, visual plot of effect size against quality score and sequential combination of trial results based on quality score. The last method permits an examination of the relation between quality and both bias and precision on the pooled estimates. We conclude that while it is possible to incorporate the effect of variation of quality of individual trials into overviews, this issue requires more study.

Exposure rates to patients' blood for surgical personnel.

BACKGROUND: Surgical personnel are at risk of contracting blood-borne diseases through exposure to patients' blood. Exposure rates for each surgical subspecialty have not been previously reported. The purpose of this study was to determine the rates of exposure to patients' blood for operating room personnel. METHODS: The study was conducted at Yale-New Haven Hospital, a level I trauma center and tertiary care hospital. During a 3-month period, exposed personnel were interviewed by a study nurse immediately after a cutaneous exposure to blood or after a sharp injury. RESULTS: During 2292 surgical procedures, 70 sharp injuries and 168 cutaneous exposures to blood were reported. The combined exposure rate (skin contact and sharp injury) was 10.4 per 100 procedures (95% confidence interval, 9.1 to 11.6) and ranged from 21.2 for general surgery to 3.3 for pediatric surgery (goodness-of-fit chi-squared, p < 0.001). The combined exposure rates were also significantly different among types of surgery and ranged from 18 for laparotomies to 4.3 for craniotomies (chi-squared, p < 0.001). The overall sharp injury rate was 3.1 per 100 procedures (95% confidence interval, 2.3 to 3.8) and ranged from 4.3 for general surgery to 1.3 for vascular surgery. CONCLUSIONS: The rate of exposure to blood for operating room personnel, which differ from prior studies, was 10.4 per 100 procedures and was highest for general surgical procedures. The differences in rates among studies might be attributable to different surgical technique, dissimilar case-mix, or different research methods relating to definition or ascertainment of exposure.

Multidrug-resistant enterococci: a threat to the surgical patient.

The enterococcus has become an important nosocomial pathogen, reported by the National Nosocomial Infections Surveillance System as the third most common pathogen associated with blood-stream infections and the second most commonly isolated pathogen overall. It is now more frequently recognized as a cause of superinfection in the surgical patient, as the possible result of the frequent use of ineffective antimicrobials for prophylaxis and treatment. Both of these findings are due, in part, to the intrinsic antimicrobial resistance of the enterococci. Of greater concern is the ready ability of this organism to acquire resistance traits. During the past 5 years, the appearance and rapid dissemination of strains with high-level resistance to vancomycin, ampicillin, gentamicin, and streptomycin have been reported; in some cases, no effective antimicrobial therapy was available to patients infected with these strains. Enterococci, in addition to their intrinsic and acquired tolerance to beta-lactams, have acquired the ability to inactivate penicillin and ampicillin via beta-lactamase production. Prompt recognition of such multiresistant enterococci, the implementation of effective infection control precautions, and rational use of antimicrobials may limit or even prevent the spread of such strains in the hospital setting.

Parenteral nutrition in cancer patients undergoing chemotherapy: a meta-analysis.

Despite numerous controlled clinical trials, the indications for parenteral nutritional support of cancer patients undergoing chemotherapy remain controversial. The results of the published trials have therefore been subjected to meta-analysis. The pooled data show that total parenteral nutrition (TPN) has a detrimental effect: best estimates associate TPN use with trends to decreased survival (relative risk 0.81; 95% confidence limits [CL] 0.62, 1.0) and poorer tumor response (odds ratio 0.68; 95% CL 0.40, 1.1), with a significant increase in infectious complications (odds ratio 4.1; 95% CL 2.4, 6.9), and no clinically significant effect on gastrointestinal or hematologic toxicity (data not amenable to quantitative analysis). The increased risk of infection persists when catheter-related septicemia is excluded, suggesting that TPN itself may increase susceptibility to infection. In summary, for the patients in trials to date, TPN was associated with net harm. Routine use of TPN in patients undergoing chemotherapy should be strongly discouraged, and trials involving specific groups of patients or modifications in TPN should be undertaken with caution.

A survey of physician's attitudes regarding management of severe group A streptococcal infections.

Intravenous immunoglobulins (IVIG) use in the management of streptococcal toxic shock syndrome remains highly controversial. To evaluate the current management of severe group A streptococcal infections and the feasibility of a randomized controlled trial comparing immunoglobulins versus placebo for streptococcal toxic shock syndrome and/or necrotizing fasciitis, a 32-question mail and web-based survey of Canadian infectious disease specialists was conducted between December 2003 and February 2004. Overall, 172 respondents (90.5%) recommended immunoglobulins as adjunctive treatment of streptococcal toxic shock compared to 67 (35.3%) for fasciitis without toxic shock and 93 (48.9%) for invasive group A streptococcal infections with hypotension. A considerable proportion of respondents agreed that a randomized clinical trial in streptococcal toxic shock (70.1%, 131/187) and necrotizing fasciitis without toxic shock (88.2%, 162/186) would be ethical. From these, a great majority would be willing to enroll patients in a trial comparing IVIG to placebo for streptococcal toxic shock (125/131, 95.4%) and necrotizing fasciitis without shock (152/162, 93.8%). These initial results clearly demonstrate ambivalence in the utilization of intravenous immunoglobulins (IVIG) in invasive group A streptococcal infections in Canada and emphasize the need for further clinical data on immunoglobulin use in streptococcal toxic shock syndrome. They also demonstrate that, although the majority of physicians recommend immunoglobulins, there is important variability between physician recommendations with regard to the indications of use, dose, and time of administration.

Decreased prevalence of virulence factors among ciprofloxacin-resistant uropathogenic Escherichia coli isolates.

Ciprofloxacin resistance was identified in 18% and 6% of consecutively collected, clinically significant urinary tract isolates of Escherichia coli from inpatients and outpatients, respectively. In comparison to ciprofloxacin-susceptible isolates, there were fewer resistant isolates that expressed beta-hemolysis (outpatient, 9% versus 87%, P < 0.0001; inpatient, 4% versus 76%, P < 0.0001) and that had a papEF genotype, genes encoding P fimbriae (outpatient, 30% versus 70%, P = 0.0004; inpatient, 26% versus 70%, P < 0.0001).

Vancomycin-resistant enterococci.

Over the last 2 decades, enterococci, formerly viewed as organisms of minimal clinical impact, have emerged as important hospital-acquired pathogens in immunosuppressed patients and intensive care units (ICUs). Vancomycin resistance in enterococci is increasing steadily. Vancomycin-resistant enterococci (VRE) composed 26% of nosocomial enterococci in 1999, a 47% increase from 1994 to 1998. More that 25% of ICU enterococci are resistant to vancomycin. Antimicrobial therapy is problematic for all VRE, but particularly when bactericidal activity is necessary. Quinipristin-dalfopristin and linezolid are 2 new approved antimicrobials for the treatment of recalcitrant infections caused byVRE. Control of the transmission of VRE, although successful in preventing infections, is neither simple nor inexpensive, and VRE has become endemic in many hospitals. However, endemicity poses serious risks to the health of current and future patients, and of itself, is expensive. Data on the cost-effectiveness of VRE prevention programs are currently lacking and urgently needed; however, because the added cost of a single VRE infection far exceeds those of gowns, gloves, and screening, it seems likely that such control programs represent significant cost savings for those hospitals willing to undertake them.

Mechanisms of glove tears and sharp injuries among surgical personnel.

OBJECTIVE: --The development of strategies to prevent exposure to blood for operating room personnel has been hampered by a lack of knowledge about the specific mechanisms of exposure. The purpose of this study was to classify the mechanisms of glove tears and sharp injuries in the operating room. DESIGN: --During a 3-month period, a nurse interviewed operating room personnel immediately after a glove tear or sharp injury had occurred. SETTING: --Yale-New Haven (Conn) Hospital is a tertiary care teaching hospital. RESULTS: --There were 249 glove tears and 70 sharp injuries. Visible skin contact with the patient's blood occurred in 156 glove tears (63%). The mechanism causing the tear could be identified in only 81 (33%). For 230 glove tears (92%), personnel were wearing single gloves. Of 70 sharp injuries, 47 (67%) were caused by needles and usually occurred during suturing. The following three mechanisms accounted for 40 sharp injuries (57%): (1) hands injured while stationary and holding an instrument, 11 (16%)-a position of risk not previously identified; (2) hands injured while retracting tissue, 12 (17%); and (3) injuries caused by sharp instruments not being used, 17 (24%). Instrument passage caused only four sharp injuries (6%). CONCLUSIONS: --The majority of glove tears have an unknown mechanism, and alteration in the manufacture or number of gloves worn may be helpful in reducing cutaneous blood exposures. The identification of specific mechanisms of sharp injuries should lead to effective strategies to prevent exposure to the human immunodeficiency virus and other blood-borne pathogens in the operating room.

Prevention of influenza and pneumococcal pneumonia in Canadian long-term care facilities: how are we doing?

BACKGROUND: Influenza and pneumococcal pneumonia are serious health problems among elderly people and a major cause of death in long-term care facilities. We describe the results of serial surveys of vaccination coverage and influenza outbreak management in Canadian long-term care facilities over the last decade. METHODS: Cross-sectional surveys consisting of questionnaires mailed to all Canadian residential long-term care facilities for elderly people in 1991 and to a random sample of respondents in 1995 and 1999. RESULTS: The response rates were 83% (430/515) in 1995 and 75% (380/506) in 1999. In 1999 the mean reported rates of influenza vaccination were 83% among residents and 35% among staff, and the mean rate of pneumococcal vaccination among residents was 71%; all 3 rates were significantly higher than those in 1991. The rates were also higher in facilities with an infection control practitioner than in those without such an individual (88% v. 82% for influenza vaccination among residents [p < 0.001], 42% v. 35% for influenza vaccination among staff [p = 0.008] and 75% v. 63% for pneumococcal vaccination among residents [p < 0.001]). Obtaining consent for vaccination on admission to the facility was associated with higher influenza and pneumococcal vaccination rates among residents (p = 0.04 and p < 0.001 respectively). Facilities with higher influenza vaccination rates among residents and staff reported lower rates of influenza outbreaks (p = 0.08 and 0.03 respectively). Despite recommendations from the National Advisory Committee on Immunization, only 50% of the facilities had policies for amantadine prophylaxis during influenza A outbreaks. Amantadine was judged effective in controlling 76% of the influenza A outbreaks and was discontinued because of side effects in 3% of the residents. INTERPRETATION: Influenza and pneumococcal vaccination rates among residents and staff in Canadian long-term care facilities have increased over the last decade but remain suboptimal. Vaccination of residents and staff against influenza is associated with a reduced risk of influenza outbreaks. Amantadine is effective in controlling influenza outbreaks in long-term care facilities.

Prospective evaluation of risk factors for bloodstream infection in patients receiving home infusion therapy.

BACKGROUND: Intravenous therapy in the outpatient and home settings is commonplace for many diseases and nutritional disorders. Few data are available on the rate of and risk factors for bloodstream infection among patients receiving such therapy. OBJECTIVE: To determine rates of and risk factors for bloodstream infection among patients receiving home infusion therapy. DESIGN: Prospective, observational cohort study. SETTING: Cleveland, Ohio, and Toronto, Ontario, Canada. PATIENTS: Patients receiving home infusion therapy through a central or midline catheter. MEASUREMENTS: Primary laboratory-confirmed bloodstream infection. RESULTS: Among 827 patients (988 catheters), the most common diagnoses were infections other than HIV (67%), cancer (24%), nutritional and digestive disease (17%), heart disease (14%), receipt of bone marrow or solid organ transplants (11%), and HIV infection (7%). Sixty-nine bloodstream infections occurred during 69,532 catheter-days (0.99 infections per 1000 days). In a Cox regression model with time-dependent covariates, independent risk factors for bloodstream infection were recent receipt of a bone marrow transplant (hazard ratio, 5.8 [95% CI, 3.0 to 11.3]), receipt of total parenteral nutrition (hazard ratio, 4.1 [CI, 2.3 to 7.2]), receipt of therapy outside the home (for example, in an outpatient clinic or physician's office) (hazard ratio, 3.6 [CI, 2.2 to 5.9]), use of a multilumen catheter (hazard ratio, 2.8 [CI, 1.7 to 4.7]), and previous bloodstream infection (hazard ratio, 2.5 [CI, 1.5 to 4.2]). Rates of bloodstream infection per 1000 catheter-days varied from 0.16 for patients with none of these 5 risk factors to 6.77 for patients with 3 or more risk factors. Centrally inserted venous catheters were associated with a higher risk than implanted ports were, but the difference was not statistically significant. CONCLUSION: Bloodstream infections seem to be infrequent among outpatients receiving infusions through central and midline catheters. However, the rate of infection increases with bone marrow transplantation, parenteral nutrition, infusion therapy in a hospital clinic or physician's office, and use of multilumen catheters. Compared with implanted ports or peripherally inserted catheters, centrally inserted venous catheters may confer greater risk for bloodstream infection.