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1.
Rev Sci Instrum ; 95(3)2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38456758

ABSTRACT

Multigap cavities are used extensively in linear accelerators to achieve velocities up to a few percent of the speed of light, driving nuclear physics research around the world. Unlike for single-gap structures, there is no closed-form expression to calculate the output beam parameters from the cavity voltage and phase. To overcome this, we propose to use a method based on the integration of the first and second moments of the beam distribution through the axially symmetric time-dependent fields of the cavity. A beam-based calibration between the model's electric field scaling and the machine's rf amplitudes is presented, yielding a fast online energy change method, returning cavity amplitude and phase necessary for a desired output beam energy and energy spread. The method is validated with 23Na6+ beam energy measurements.

2.
J Hosp Infect ; 145: 59-64, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38141666

ABSTRACT

BACKGROUND: Mandatory mask-wearing policies were one of several measures employed to reduce hospital-acquired SARS-CoV-2 infection throughout the pandemic. Many nations have removed healthcare mask mandates, but there remains a risk of new SARS-CoV-2 variants or epidemics of other respiratory viruses. AIM: To demonstrate the impact of removing the healthcare mask mandate. METHODS: SARS-CoV-2 infections were analysed in a large teaching hospital for 40 weeks in 2022 using a controlled interrupted time-series design. The intervention was the removal of a staff/visitor surgical mask-wearing policy for the most wards at week 26 (intervention group) with a subset of specific wards retaining the mask policy (control group). The hospital-acquired SARS-CoV-2 infection rate was adjusted by the underlying community infection rate. FINDINGS: In the context of a surge in SARS-CoV-2 infection, removal of the mask mandate for staff/visitors was not associated with a statistically significant change in the rate of nosocomial SARS-CoV-2 infection in the intervention group (incidence rate ratio: 1.105; 95% confidence interval: 0.523-2.334; P = 0.79) and there was no post-intervention trend (1.013; 0.932-1.100; P = 0.76) to suggest a delayed effect. The control group also showed no immediate or delayed change in infection rate. CONCLUSION: No evidence was found that removal of a staff/visitor mask-wearing policy had a significant effect on the rate of hospital-acquired SARS-CoV-2 infection. This does not demonstrate that masks were ineffective through the pandemic, but provides some objective evidence to justify the removal of healthcare mask mandates once there was widespread immunity and reduced disease severity.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , COVID-19/prevention & control , SARS-CoV-2 , Pandemics/prevention & control , Masks , Hospitals
3.
JAC Antimicrob Resist ; 4(3): dlac055, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35756574

ABSTRACT

Background: ICUs are settings of high antifungal consumption. There are few data on prescribing practices in ICUs to guide antifungal stewardship implementation in this setting. Methods: An antifungal therapy (AFT) service evaluation (15 May-19 November 2019) across ICUs at three London hospitals, evaluating consumption, prescribing rationale, post-prescription review, de-escalation and final invasive fungal infection (IFI) diagnostic classification. Results: Overall, 6.4% of ICU admissions (305/4781) received AFT, accounting for 11.41 days of therapy/100 occupied bed days (DOT/100 OBD). The dominant prescribing mode was empirical (41% of consumption), followed by targeted (22%), prophylaxis (18%), pre-emptive (12%) and non-invasive (7%). Echinocandins were the most commonly prescribed drug class (4.59 DOT/100 OBD). In total, 217 patients received AFT for suspected or confirmed IFI; 12%, 10% and 23% were classified as possible, probable or proven IFI, respectively. Hence, in 55%, IFI was unlikely. Proven IFI (n = 50) was mostly invasive candidiasis (92%), of which 48% had been initiated on AFT empirically before yeast identification. Where on-site (1 → 3)-ß-d-glucan (BDG) testing was available (1 day turnaround), in those with suspected but unproven invasive candidiasis, median (IQR) AFT duration was 10 (7-15) days with a positive BDG (≥80 pg/mL) versus 8 (5-9) days with a negative BDG (<80 pg/mL). Post-prescription review occurred in 79% of prescribing episodes (median time to review 1 [0-3] day). Where suspected IFI was not confirmed, 38% episodes were stopped and 4% de-escalated within 5 days. Conclusions: Achieving a better balance between promptly treating IFI patients and avoiding inappropriate antifungal prescribing in the ICU requires timely post-prescription review by specialist multidisciplinary teams and improved, evidence-based-risk prescribing strategies incorporating rapid diagnostics to guide AFT start and stop decisions.

4.
J Hosp Infect ; 111: 140-147, 2021 May.
Article in English | MEDLINE | ID: mdl-33581245

ABSTRACT

BACKGROUND: Novel rapid antimicrobial susceptibility testing (RAST) methods promise quicker de-escalation of broad-spectrum antibiotics. However, other behavioural and situational factors influencing antimicrobial prescription are not well known. AIM: To explore factors associated with optimal antimicrobial prescription in patients with Gram-negative bloodstream infection and to propose specific scenarios in which a rapid antimicrobial susceptibility result may help to optimize prescribing. METHODS: Exploratory survey (April-August 2018) in the UK and Spain using clinical case-related questions. Seniority, specialty and country of practice were recorded. Cases described patients with Gram-negative bloodstream infections, their empirical treatment and clinical course and the hypothetical RAST result. Respondents chose one of several options regarding antibiotic treatment management. Microbiologically optimal antibiotic choice (MOAC) was agreed by expert consensus beforehand. Responses were categorized as MOAC, request for support or sub-optimal choice. The relationship between the RAST result and the clinical course was defined as concordant (susceptible organism-clinical improvement; resistant organism-clinical deterioration) or as discordant otherwise. FINDINGS: A total of 426 respondents (UK: 332; Spain: 94) and 1494 answers were analysed. Multivariate analysis identified that requests for support were 87% less likely in Spain; that antimicrobial resistance and clinical deterioration were associated with both increased request for support (odds ratio (OR) 7.66 and OR 4.26, respectively) and MOAC (OR 2.08 and OR 2.06, respectively). A discordant clinical course was associated with 82% lower odds for MOAC. Out-of-hours results, seniority and specialty did not have an effect. CONCLUSION: Antimicrobial choice is influenced by each country's type of practice, clinical course and susceptibility results. Antimicrobial resistance was associated with increased optimal treatment, suggesting RAST may be less useful for step-down decisions in settings with low baseline resistance rates.


Subject(s)
Anti-Bacterial Agents , Gram-Negative Bacterial Infections , Practice Patterns, Physicians' , Prescriptions , Sepsis , Anti-Bacterial Agents/therapeutic use , Gram-Negative Bacterial Infections/drug therapy , Humans , Microbial Sensitivity Tests , Sepsis/drug therapy , Spain , Surveys and Questionnaires
6.
Clin Microbiol Infect ; 25(3): 380.e1-380.e7, 2019 Mar.
Article in English | MEDLINE | ID: mdl-29906594

ABSTRACT

OBJECTIVES: Rapid and accurate sexually transmitted infection diagnosis can reduce onward transmission and improve treatment efficacy. We evaluated the accuracy of a 15-minute run-time recombinase polymerase amplification-based prototype point-of-care test (TwistDx) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). METHODS: Prospective, multicentre study of symptomatic and asymptomatic patients attending three English sexual health clinics. Research samples provided were additional self-collected vulvovaginal swab (SCVS) (female participants) and first-catch urine (FCU) aliquot (female and male participants). Samples were processed blind to the comparator (routine clinic CT/NG nucleic acid amplification test (NAAT)) results. Discrepancies were resolved using Cepheid CT/NG GeneXpert. RESULTS: Both recombinase polymerase amplification and routine clinic NAAT results were available for 392 male and 395 female participants. CT positivity was 8.9% (35/392) (male FCU), 7.3% (29/395) (female FCU) and 7.1% (28/395) (SCVS). Corresponding NG positivity was 3.1% (12/392), 0.8% (3/395) and 0.8% (3/395). Specificity and positive predictive values were 100% for all sample types and both organisms, except male CT FCU (99.7% specificity (95% confidence interval (CI) 98.4-100.0; 356/357), 97.1% positive predictive value (95% CI 84.7-99.9; 33/34)). For CT, sensitivity was ≥94.3% for FCU and SCVS. CT sensitivity for female FCU was higher (100%; 95% CI, 88.1-100; 29/29) than for SCVS (96.4%; 95% CI, 81.7-99.9; 27/28). NG sensitivity and negative predictive values were 100% in FCU (male and female). CONCLUSIONS: This prototype test has excellent performance characteristics, comparable to currently used NAATs, and fulfils several World Health Organization ASSURED criteria. Its rapidity without loss of performance suggests that once further developed and commercialized, this test could positively affect clinical practice and public health.


Subject(s)
Chlamydia trachomatis/isolation & purification , Neisseria gonorrhoeae/isolation & purification , Nucleic Acid Amplification Techniques/standards , Point-of-Care Testing , Sexually Transmitted Diseases/diagnosis , Adolescent , Adult , Aged , Ambulatory Care Facilities , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Prospective Studies , Sensitivity and Specificity , Specimen Handling , Young Adult
7.
Clin Microbiol Infect ; 25(7): 865-871, 2019 Jul.
Article in English | MEDLINE | ID: mdl-30391581

ABSTRACT

OBJECTIVES: We conducted a cluster-randomized feasibility trial of 90-minute Chlamydia trachomatis tests and same day on-site treatment ('Test n Treat/TnT') in six technical colleges in London, England, to assess TnT uptake rates; follow-up rates; prevalence of C. trachomatis at baseline and 7 months; time to treatment; acceptability of TnT. METHODS: Participants completed questionnaires and provided genitourinary samples at baseline and 7 months. Participants were informed that baseline samples would not be tested for 7 months and were advised to get screened independently. Colleges were randomly allocated 1:1 to intervention (TnT) or control (no TnT). One month and 4 months post recruitment, participants at intervention colleges were texted invitations for on-site free C. trachomatis tests. A purposive sample of students who did/did not attend for screening were interviewed (n = 26). RESULTS: Five hundred and nine sexually active students were recruited: median age 17.9 years, 47% male, 50% black ethnicity, 55% reporting two or more sexual partners in the previous year. TnT uptake was 13% (33/259; 95% CI 8.9-17.4%) at 1 month and 10% (26/259; 6.7-14.4%) at 4 months with overall C. trachomatis positivity 5.1% (3/59; 1.1-14.2%). Follow-up at 7 months was 62% (317/509) for questionnaires and 52% (264/509) for samples. C. trachomatis prevalence was 6.2% (31/503) at baseline and 6.1% (16/264) at 7 months. Median time from test to treatment was 15 h. Interviews suggested low test uptake was associated with not feeling at risk, perceptions of stigma, and little knowledge of sexually transmitted infections (STIs). CONCLUSIONS: Despite high C. trachomatis rates at baseline and follow-up, uptake of testing was low. Like many countries, England urgently needs better sex education, including making STI testing routine/normal. Trial registration ISRCTN58038795.


Subject(s)
Chlamydia Infections/diagnosis , Chlamydia Infections/drug therapy , Chlamydia trachomatis/isolation & purification , Sexually Transmitted Diseases/diagnosis , Sexually Transmitted Diseases/drug therapy , Adolescent , Chlamydia Infections/epidemiology , Diagnostic Screening Programs , Ethnicity , Feasibility Studies , Female , Humans , London/epidemiology , Male , Prevalence , Risk Factors , Sexual Behavior , Sexual Partners , Sexually Transmitted Diseases/epidemiology , Students , Surveys and Questionnaires , Time-to-Treatment , Young Adult
8.
J Hosp Infect ; 101(3): 276-284, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30471317

ABSTRACT

BACKGROUND: During high-incidence influenza seasons, a robust infection prevention and control policy is imperative to reduce nosocomial transmission of influenza. AIM: To assess the impact of influenza point-of-care testing (POCT) in an emergency department (ED) and patient cohorting on an influenza ward on infection prevention and control and clinical outcomes. METHODS: Influenza POCT was operational in the study ED from 21st January 2018 and patient cohorting was operational on an influenza ward from 25th January 2018. A retrospective 'before-after' analysis was performed with pre-intervention defined as 1st November 2017 to 20th January 2018 and post-intervention defined as 21st January 2018 to 30th April 2018. The primary outcome was the rate of hospital-acquired influenza. Secondary outcomes included antiviral prescription and length of stay. The length of time that inpatients remained influenza-positive was estimated by polymerase chain reaction (PCR). FINDINGS: There were 654 inpatients with confirmed influenza during the 2017/18 influenza season: 223 pre- and 431 post-intervention. Post-intervention, there were fewer cases of hospital-acquired influenza per day (0.66 vs 0.95, P < 0.0001), median length of stay was shorter (5.5 vs 7.5 days, P = 0.005) and antiviral prescription was more frequent (80% vs 64.1%, P < 0.0001). Cohorting released 779 single rooms for use elsewhere in the trust. The fixed probability of being PCR-negative by the next day (P) was 0.14 [95% confidence interval (CI) 0.12-0.16] for immunocompetent patients. This implies that half of immunocompetent patients are PCR-negative by five days post-diagnosis (95% CI 5-6). CONCLUSION: Influenza POCT in an ED and patient cohorting on an influenza ward were associated with reduced nosocomial transmission of influenza and improved patient flow. A policy of retesting immunocompetent patients five days post-diagnosis could allow half of these patients to come out of respiratory isolation earlier.


Subject(s)
Cross Infection/diagnosis , Cross Infection/prevention & control , Disease Transmission, Infectious/prevention & control , Infection Control/methods , Influenza, Human/diagnosis , Influenza, Human/prevention & control , Point-of-Care Testing/organization & administration , Adult , Aged , Aged, 80 and over , Antiviral Agents/therapeutic use , Cross Infection/epidemiology , Cross Infection/transmission , Drug Utilization , Female , Humans , Incidence , Influenza, Human/epidemiology , Influenza, Human/transmission , Length of Stay , Male , Middle Aged , Retrospective Studies
9.
J Hosp Infect ; 101(3): 285-288, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30562558

ABSTRACT

The cobas Liat influenza A/B and respiratory syncytial virus (RSV) assay (Liat) was used in the adult emergency department of a large London hospital from 21st January 2018 to 14th April 2018. Influenza was detected in 308 of 1027 (30%) samples tested; influenza A in 157 (15.3%), influenza B in 149 (14.5%) and RSV in 28 (2.7%). When compared against Fast Track Diagnostics Respiratory Pathogens 21 multiplex polymerase chain reaction and Cepheid Xpert Xpress Flu/RSV assay, Liat performance for the detection of influenza A or B was: sensitivity 85% [95% confidence interval (CI) 76-92)], specificity 98% (95% CI 97-99), negative predictive value 94% (95% CI 92-96) and positive predictive value 95% (95% CI 91-97).


Subject(s)
Diagnostic Tests, Routine/methods , Emergency Service, Hospital , Influenza, Human/diagnosis , Point-of-Care Systems , Respiratory Syncytial Virus Infections/diagnosis , Adult , Humans , Incidence , Influenza A virus/isolation & purification , Influenza B virus/isolation & purification , London , Predictive Value of Tests , Respiratory Syncytial Viruses/isolation & purification , Retrospective Studies , Sensitivity and Specificity
10.
Eur J Clin Microbiol Infect Dis ; 36(5): 839-846, 2017 May.
Article in English | MEDLINE | ID: mdl-28025699

ABSTRACT

This study evaluates whether estimated multidrug resistance (MDR) levels are dependent on the design of the surveillance system when using routine microbiological data. We used antimicrobial resistance data from the Antibiotic Resistance and Prescribing in European Children (ARPEC) project. The MDR status of bloodstream isolates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was defined using European Centre for Disease Prevention and Control (ECDC)-endorsed standardised algorithms (non-susceptible to at least one agent in three or more antibiotic classes). Assessment of MDR status was based on specified combinations of antibiotic classes reportable as part of routine surveillance activities. The agreement between MDR status and resistance to specific pathogen-antibiotic class combinations (PACCs) was assessed. Based on all available antibiotic susceptibility testing, the proportion of MDR isolates was 31% for E. coli, 30% for K. pneumoniae and 28% for P. aeruginosa isolates. These proportions fell to 9, 14 and 25%, respectively, when based only on classes collected by current ECDC surveillance methods. Resistance percentages for specific PACCs were lower compared with MDR percentages, except for P. aeruginosa. Accordingly, MDR detection based on these had low sensitivity for E. coli (2-41%) and K. pneumoniae (21-85%). Estimates of MDR percentages for Gram-negative bacteria are strongly influenced by the antibiotic classes reported. When a complete set of results requested by the algorithm is not available, inclusion of classes frequently tested as part of routine clinical care greatly improves the detection of MDR. Resistance to individual PACCs should not be considered reflective of MDR percentages in Enterobacteriaceae.


Subject(s)
Bacteremia/epidemiology , Drug Resistance, Multiple, Bacterial , Epidemiological Monitoring , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/isolation & purification , Gram-Negative Bacterial Infections/epidemiology , Bacteremia/microbiology , Europe/epidemiology , Gram-Negative Bacterial Infections/microbiology , Humans , Microbial Sensitivity Tests , Prevalence
11.
Clin Microbiol Infect ; 22 Suppl 4: S63-81, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27460910

ABSTRACT

In 2009 the first European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guideline for diagnosing Clostridium difficile infection (CDI) was launched. Since then newer tests for diagnosing CDI have become available, especially nucleic acid amplification tests. The main objectives of this update of the guidance document are to summarize the currently available evidence concerning laboratory diagnosis of CDI and to formulate and revise recommendations to optimize CDI testing. This update is essential to improve the diagnosis of CDI and to improve uniformity in CDI diagnosis for surveillance purposes among Europe. An electronic search for literature concerning the laboratory diagnosis of CDI was performed. Studies evaluating a commercial laboratory test compared to a reference test were also included in a meta-analysis. The commercial tests that were evaluated included enzyme immunoassays (EIAs) detecting glutamate dehydrogenase, EIAs detecting toxins A and B and nucleic acid amplification tests. Recommendations were formulated by an executive committee, and the strength of recommendations and quality of evidence were graded using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system. No single commercial test can be used as a stand-alone test for diagnosing CDI as a result of inadequate positive predictive values at low CDI prevalence. Therefore, the use of a two-step algorithm is recommended. Samples without free toxin detected by toxins A and B EIA but with positive glutamate dehydrogenase EIA, nucleic acid amplification test or toxigenic culture results need clinical evaluation to discern CDI from asymptomatic carriage.


Subject(s)
Clostridioides difficile/isolation & purification , Clostridium Infections/diagnosis , European Union/organization & administration , Societies, Medical/organization & administration , Algorithms , Bacterial Toxins/metabolism , Clostridioides difficile/genetics , Clostridioides difficile/metabolism , Clostridium Infections/microbiology , DNA, Bacterial/genetics , Early Diagnosis , Humans , Population Surveillance , Practice Guidelines as Topic , Reagent Kits, Diagnostic , Sensitivity and Specificity
12.
Eur J Clin Microbiol Infect Dis ; 35(2): 251-9, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26661400

ABSTRACT

Clostridium difficile infection (CDI) is associated with high mortality. Reducing incidence is a priority for patients, clinicians, the National Health Service (NHS) and Public Health England alike. In June 2012, fidaxomicin (FDX) was launched for the treatment of adults with CDI. The objective of this evaluation was to collect robust real-world data to understand the effectiveness of FDX in routine practice. In seven hospitals introducing FDX between July 2012 and July 2013, data were collected retrospectively from medical records on CDI episodes occurring 12 months before/after the introduction of FDX. All hospitalised patients aged ≥18 years with primary CDI (diarrhoea with presence of toxin A/B without a previous CDI in the previous 3 months) were included. Recurrence was defined as in-patient diarrhoea re-emergence requiring treatment any time within 3 months after the first episode. Each hospital had a different protocol for the use of FDX. In hospitals A and B, where FDX was used first line for all primary and recurrent episodes, the recurrence rate reduced from 10.6 % to 3.1 % and from 16.3 % to 3.1 %, with a significant difference in 28-day mortality from 18.2 % to 3.1 % (p < 0.05) and 17.3 % to 6.3 % (p < 0.05) for hospitals A and B, respectively. In hospitals using FDX in selected patients only, the changes in recurrence rates and mortality were less marked. The pattern of adoption of FDX appears to affect its impact on CDI outcome, with maximum reduction in recurrence and all-cause mortality where it is used as first-line treatment.


Subject(s)
Aminoglycosides/therapeutic use , Anti-Bacterial Agents/therapeutic use , Clostridioides difficile/drug effects , Clostridium Infections/drug therapy , Clostridium Infections/mortality , Adult , Aged , Aged, 80 and over , Clostridium Infections/microbiology , Diarrhea/microbiology , England , Female , Fidaxomicin , Humans , Male , Middle Aged , Mortality , Patient Readmission/statistics & numerical data , Recurrence , Retrospective Studies , Secondary Care , Secondary Care Centers
13.
Clin Microbiol Infect ; 20(10): O609-18, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24422878

ABSTRACT

A series of extensively drug-resistant isolates of Pseudomonas aeruginosa from two outbreaks in UK hospitals were characterized by whole genome sequencing (WGS). Although these isolates were resistant to antibiotics other than colistin, we confirmed that they are still sensitive to disinfectants. The sequencing confirmed that isolates in the larger outbreak were serotype O12, and also revealed that they belonged to sequence type ST111, which is a major epidemic strain of P. aeruginosa throughout Europe. As this is the first reported sequence of an ST111 strain, the genome was examined in depth, focusing particularly on antibiotic resistance and potential virulence genes, and on the reported regions of genome plasticity. High degrees of sequence similarity were discovered between outbreak isolates collected from recently infected patients, isolates from sinks, an isolate from the sewer, and a historical isolate, suggesting that the ST111 strain has been endemic in the hospital for many years. The ability to translate easily from outbreak investigation to detailed genome biology by use of the same data demonstrates the flexibility of WGS application in a clinical setting.


Subject(s)
Cross Infection/microbiology , Drug Resistance, Bacterial , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/genetics , Sequence Analysis, DNA/methods , Anti-Bacterial Agents/pharmacology , Cross Infection/epidemiology , Disease Outbreaks , Drug Resistance, Bacterial/drug effects , Genome, Bacterial , Humans , Phylogeny , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/isolation & purification , Serotyping , Sewage/microbiology , United Kingdom/epidemiology
15.
J Hosp Infect ; 82(1): 19-24, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22841682

ABSTRACT

BACKGROUND: Multidrug-resistant Pseudomonas aeruginosa (MDR-P) expressing VIM-metallo-beta-lactamase is an emerging infection control problem. The source of many such infections is unclear, though there are reports of hospital outbreaks of P. aeruginosa related to environmental contamination, including tap water. AIM: We describe two outbreaks of MDR-P, sensitive only to colistin, in order to highlight the potential for hospital waste-water systems to harbour this organism. METHODS: The outbreaks were investigated by a combination of descriptive epidemiology, inspection and microbiological sampling of the environment, and molecular strain typing. FINDINGS: The outbreaks occurred in two English hospitals; each involved a distinct genotype of MDR-P. One outbreak was hospital-wide, involving 85 patients, and the other was limited to four cases in one specialized medical unit. Extensive environmental sampling in each outbreak yielded MDR-P only from the waste-water systems. Inspection of the environment and estates records revealed many factors that may have contributed to contamination of clinical areas, including faulty sink, shower and toilet design, clean items stored near sluices, and frequent blockages and leaks from waste pipes. Blockages were due to paper towels, patient wipes, or improper use of bedpan macerators. Control measures included replacing sinks and toilets with easier-to-clean models less prone to splashback, educating staff to reduce blockages and inappropriate storage, reviewing cleaning protocols, and reducing shower flow rates to reduce flooding. These measures were followed by significant reductions in cases. CONCLUSION: The outbreaks highlight the potential of hospital waste systems to act as a reservoir of MDR-P and other nosocomial pathogens.


Subject(s)
Disease Outbreaks , Drug Resistance, Multiple, Bacterial , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/isolation & purification , Wastewater/microbiology , Anti-Bacterial Agents/pharmacology , Hospitals , Humans , Microbial Sensitivity Tests , Molecular Typing , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/classification
16.
J Hosp Infect ; 76(1): 18-22, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20638749

ABSTRACT

Commonly used immunoassays have limitations as stand-alone tests for the diagnosis of Clostridium difficile infection (CDI). In particular, the specificity of these assays means that these tests generate a relatively large number of false-positive results. We introduced a two-stage regimen for CDI as routine. Unformed stool samples received in our laboratory were initially tested with a Meridian Premier enzyme immunoassay (EIA) and positive samples were retested with reference testing methods (toxigenic culture and cell cytotoxicity assay). Clinicians received diagnostically useful information on the day that the sample arrived in the laboratory, with definitive negative and provisional positive results made available. We reviewed the first 3643 unformed stool specimens of which 158/3643 (4.3%) were provisionally positive by EIA. Of the 158 samples that were EIA positive, 119 were confirmed as being positive by at least one of the reference methods, giving a positive predictive value in this population of 75% (95% confidence interval: 67.6-81.7%). Comparison of the optical density values of the EIA lying between true and false-positive results suggests that the introduction of a second cut-off value would improve diagnostics. A test with two cut-offs would give the following results: 'positive', 'negative' and 'indeterminate result, please perform confirmatory test'. This algorithm was a simple and cost-effective method to immediately improve diagnostics, but there is an urgent need for further research in laboratory diagnosis for CDI.


Subject(s)
Bacteriological Techniques/methods , Clostridioides difficile/isolation & purification , Enterocolitis, Pseudomembranous/diagnosis , Aged , Aged, 80 and over , Algorithms , Cell Culture Techniques , Cell Survival , Feces/microbiology , Humans , Immunoenzyme Techniques/methods , Predictive Value of Tests
17.
Acta Paediatr ; 99(11): 1691-4, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20528798

ABSTRACT

OBJECTIVE: Meticillin-resistant staphylococcus aureus (MRSA) colonization on neonatal units is a common and important clinical problem. Effectiveness of polymerase chain reaction (PCR) for detecting MRSA nasal colonization of infants was evaluated and compared to culture-based methods. The effect of skin decolonization in affected infants was studied. METHODS: Paired nasal swabs were collected from infants in our neonatal unit over a 12-month period (September 2007-2008). Colonization with MRSA was determined with a commercially available PCR method and compared to culture. RESULTS: A total of 696 paired nasal swabs were taken. Three infants were colonized at the beginning and were included. There were positive PCRs in 12 infants. Five infants cultured MRSA from a nasal swab at the same time. No infants were culture-positive when PCR was negative (sensitivity 100%, specificity 99% compared to culture). PCR results were available within 24 h. Five infants were PCR+ and isolated meticillin-sensitive Staphylococcus aureus. This organism gave a false-positive PCR result. Two infants transferred in on broad-spectrum antibiotics were PCR+ and negative by culture. Decolonization led to negative nasal PCR and culture in 4/5 infants to discharge. CONCLUSIONS: PCR methods are sensitive and specific for detection of MRSA colonization in newborn infants of all gestations with results 1-2 days before culture.


Subject(s)
Methicillin-Resistant Staphylococcus aureus/isolation & purification , Nasal Mucosa/microbiology , Polymerase Chain Reaction/methods , Staphylococcal Infections/diagnosis , Colony Count, Microbial , Culture Techniques/methods , Female , Gestational Age , Humans , Infant, Newborn , Infant, Premature , Infant, Premature, Diseases/diagnosis , Intensive Care Units, Neonatal , Male , Methicillin-Resistant Staphylococcus aureus/drug effects , Sensitivity and Specificity
20.
Clin Infect Dis ; 42(12): 1719-25, 2006 Jun 15.
Article in English | MEDLINE | ID: mdl-16705578

ABSTRACT

BACKGROUND: Hyperlactatemia is an important and common complication of severe malaria. We investigated changes in fluid compartment volumes in patients with severe malaria and control patients with the use of bioimpedence analysis. METHODS: We estimated extracellular water and total body water volumes in a total of 180 children: 56 with severe malaria, 94 with moderate malaria, 24 with respiratory tract infection, and 6 with severe diarrhea. RESULTS: There was a mean (+/-SD) decrease in total body water volume of 17+/-24 mL/kg (or 3% of total body water volume) in patients with severe malaria. This compares with a mean (+/-SD) decrease in total body water volume of 33+/-28 mL/kg (or 6% of total body water volume) in patients with severe diarrhea. There was no increase in extracellular water volume in patients with severe malaria, suggesting no significant intravascular volume depletion in patients with severe malaria. There was no relationship between lactatemia and any changes in fluid compartment volumes. CONCLUSIONS: The changes in fluid volumes that were observed are unlikely to be of physiological significance in the pathophysiology of severe malaria.


Subject(s)
Acidosis, Lactic/etiology , Dehydration/complications , Malaria, Falciparum/complications , Antimalarials/therapeutic use , Child , Child, Preschool , Diarrhea/complications , Female , Gabon , Humans , Infant , Malaria, Falciparum/drug therapy , Male , Quinine/therapeutic use , Respiratory Tract Infections/complications
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