Biomedical subjects

Denis Spelman

Publications and source records attributed to Denis Spelman.

17 recordsLinked to original sources

PubMed2006

Large outbreak of infection and colonization with gram-negative pathogens carrying the metallo- beta -lactamase gene blaIMP-4 at a 320-bed tertiary hospital in Australia.

A large outbreak of infection and colonization with multiple genera of gram-negative bacilli carrying the metallo- beta -lactamase gene bla(IMP-4) occurred in a 36-bed intensive care unit at a tertiary hospital in Australia. The organisms emerged rapidly, caused severe infections, and contributed to mortality. Controlling the spread of these organisms remains a challenge for all staff involved.

Adolescent↗

PubMed2006

Carriage of multiple subtypes of methicillin-resistant Staphylococcus aureus by intensive care unit patients.

OBJECTIVE: To determine how consistently patients are colonized with methicillin-resistant Staphylococcus aureus (MRSA) at various sites and how many subtypes can be carried simultaneously by a single patient. SETTING: A 28-bed Intensive care unit in a tertiary-care referral hospital. METHODS: A total of 1,181 patients were screened by culture of swab specimens obtained from the nose, throat, groin, and axilla on admission to the intensive care unit (ICU), twice weekly during their ICU stay, and at discharge. RESULTS: MRSA was isolated at least once from 224 patients. Of these isolates, 359 were selected from 32 patients to be subtyped using pulsed-field gel electrophoresis. The rate of compliance with collection of swab specimens was 79.9%. The combination of sites colonized varied frequently over time for many patients. Of patients who had swab specimens obtained twice in 1 day, 8.7% had discordant results from the 2 swab sets. No patient had a clinical isolate that was not of an identical subtype to an isolate from an anatomical site that was sampled for screening. Half the patients carried multiple subtypes during their stay, with up to 4 subtypes per patient. CONCLUSIONS: The findings of this study may indicate that these patients have been colonized with MRSA on more than one occasion, possibly because of multiple breaches in infection control procedure. In MRSA-colonized patients, anatomical sites were intermittently colonized and carriage of multiple subtypes was common. These findings indicate that MRSA carriage is not a fixed state but may vary over time.

Axilla↗

PubMed2006

Successful treatment and cerebrospinal fluid penetration of oral linezolid in a patient with coagulase-negative Staphylococcus ventriculitis.

OBJECTIVE: To describe a case of coagulase-negative Staphylococcus ventriculitis successfully treated with oral linezolid, for which good cerebrospinal fluid (CSF) penetration was observed. CASE SUMMARY: A 69-year-old man had an extraventricular drain inserted following a right cerebellar infarct. On day 6, the CSF culture was positive for coagulase-negative staphylococci; intravenous vancomycin 1 g daily was initiated to treat ventriculitis. A ventriculoperitoneal shunt, inserted on day 35 to manage communicating hydrocephalus, was subsequently removed as symptoms suggesting infection presented. Coagulase-negative Staphylococcus was isolated from shunt reservoir aspirate, and intrathecal vancomycin 10 mg daily was added to the treatment regimen. On day 61, vancomycin was stopped and oral linezolid 600 mg twice daily was started. Linezolid was discontinued 22 days later, with no evidence of ongoing infection. Four blood samples were collected around the seventh dose of linezolid and 5 CSF samples were collected on separate days during treatment. Linezolid concentrations were measured in plasma and CSF by HPLC. Using an ADAPT II maximum a priori Bayesian estimator module, a 2 compartment pharmacokinetic model was fitted to the plasma linezolid concentration data and CSF:predicted plasma concentration ratios (ranging from 0.27 to 1.02) were derived. All CSF concentrations exceeded the reported 90% minimum inhibitory concentration of 2 mg/L for linezolid against coagulase-negative staphylococci. DISCUSSION: Evidence of the effectiveness of linezolid against central nervous system infections is growing; however, limited data exist describing its CSF penetration. Oral linezolid exhibited good CSF penetration in this patient, which corresponded to positive clinical response. CONCLUSIONS: Oral linezolid may play a valuable role in the treatment of multiresistant gram-positive central nervous system infections.

Acetamides↗

PubMed2006

A binational cohort study of ventilator-associated pneumonia in Denmark and Australia.

The objective was to determine the incidence and prognosis of ventilator-associated pneumonia (VAP) in intensive care units (ICUs) in Melbourne (29-bed ICU), Australia and Aarhus and Aalborg (22-bed unit and 8-bed ICU, respectively), Denmark and to characterize participating ICUs with regard to prevalence of nosocomial type bacterial pathogens, antibiotic resistance and antibiotic consumption. In this prospective cohort study 25 patients in Melbourne and 32 patients in Aarhus + Aalborg had a first episode of VAP. The incidence of VAP per 1000 ventilator d was 6.2 in Melbourne and 9.5 in Aarhus + Aalborg. Case fatality during hospital admission was 28% and 59%, respectively (unadjusted odds ratio (OR) 0.3, 95% confidence interval (CI) 0.1-0.8). OR adjusted for age and APACHE II score was 0.2 (95% CI 0.1-1.0). Nosocomial type pathogens including methicillin resistant Staphylococcus aureus were more prevalent in Melbourne, and antibiotic consumption per VAP patient was 35% higher in Melbourne than in Aarhus + Aalborg. To judge from the present data, there seems to be a complicated interrelationship between prognosis on the 1 hand and antibiotic consumption and resistance on the other. A more favourable prognosis was found in Melbourne, where levels of antibiotic consumption and antimicrobial resistance were higher than in Aarhus + Aalborg.

APACHE↗

PubMed2006

Cost-effectiveness of a post-splenectomy registry for prevention of sepsis in the asplenic.

BACKGROUND: Overwhelming, sometimes fatal infections represent a lifelong risk after surgical removal of the spleen, or in patients who develop hyposplenism as a consequence of illnesses. This risk may be reduced by all or a combination of vaccination, antibiotic prophylaxis and education. We aimed to determine if a registry approach to delivering these interventions would be cost effective using our own experience and published data. METHOD: The decision model compared a cohort of 1,000 people covered by a registry to a cohort of 1,000 people with no registry. The impact of the registry was assessed in terms of achieved rates of vaccination, chemoprophylaxis and education, consequent outcomes of overwhelming post-splenectomy infection (OPSI) and mortality (years of life lived). The cost-effectiveness of the registry compared with no registry was estimated in terms of additional cost per case of OPSI avoided and as additional cost per life year gained. RESULTS: In the first two years, the additional cost of the registry was dollar 152,611 per case of OPSI avoided or dollar 205,931 per life year gained. After this initial registration period the cost-effectiveness improves over time, such that over the cohort lifetime a post-splenectomy register is associated with an additional cost of dollar 105,159 per case of OPSI avoided or dollar 16,113 per life year gained. CONCLUSION: A registry-based approach is likely to prove cost effective in terms of mortality and rates of OPSI avoided.

Antibiotic Prophylaxis↗

PubMed2006

Heteroresistance to colistin in multidrug-resistant Acinetobacter baumannii.

Multidrug-resistant Acinetobacter baumannii has emerged as a significant clinical problem worldwide and colistin is being used increasingly as "salvage" therapy. MICs of colistin against A. baumannii indicate its significant activity. However, resistance to colistin in A. baumannii has been reported recently. Clonotypes of 16 clinical A. baumannii isolates and ATCC 19606 were determined by pulsed-field gel electrophoresis (PFGE), and colistin MICs were measured. The time-kill kinetics of colistin against A. baumannii ATCC 19606 and clinical isolate 6 were investigated, and population analysis profiles (PAPs) were conducted. Resistance development was investigated by serial passaging with or without exposure to colistin. Five different PFGE banding patterns were found in the clinical isolates. MICs of colistin against all isolates were within 0.25 to 2 microg/ml. Colistin showed early concentration-dependent killing, but bacterial regrowth was observed at 24 h. PAPs revealed that heteroresistance to colistin occurred in 15 of the 16 clinical isolates. Subpopulations (<0.1% from inocula of 10(8) to 10(9) CFU/ml) of ATCC 19606, and most clinical isolates grew in the presence of colistin 3 to 10 microg/ml. Four successive passages of ATCC 19606 in broth containing colistin (up to 200 microg/ml) substantially increased the proportion of the resistant subpopulations able to grow in the presence of colistin at 10 microg/ml from 0.000023 to 100%; even after 16 passages in colistin-free broth, the proportion only decreased to 2.1%. This represents the first demonstration of heterogeneous colistin-resistant A. baumannii in "colistin-susceptible" clinical isolates. Our findings give a strong warning that colistin-resistant A. baumannii may be observed more frequently due to potential suboptimal dosage regimens recommended in the product information of some products of colistin methanesulfonate.

Acinetobacter Infections↗

PubMed2005

Staphylococcus aureus endocarditis: a consequence of medical progress.

CONTEXT: The global significance of infective endocarditis (IE) caused by Staphylococcus aureus is unknown. OBJECTIVES: To document the international emergence of health care-associated S aureus IE and methicillin-resistant S aureus (MRSA) IE and to evaluate regional variation in patients with S aureus IE. DESIGN, SETTING, AND PARTICIPANTS: Prospective observational cohort study set in 39 medical centers in 16 countries. Participants were a population of 1779 patients with definite IE as defined by Duke criteria who were enrolled in the International Collaboration on Endocarditis-Prospective Cohort Study from June 2000 to December 2003. MAIN OUTCOME MEASURE: In-hospital mortality. RESULTS: S aureus was the most common pathogen among the 1779 cases of definite IE in the International Collaboration on Endocarditis Prospective-Cohort Study (558 patients, 31.4%). Health care-associated infection was the most common form of S aureus IE (218 patients, 39.1%), accounting for 25.9% (Australia/New Zealand) to 54.2% (Brazil) of cases. Most patients with health care-associated S aureus IE (131 patients, 60.1%) acquired the infection outside of the hospital. MRSA IE was more common in the United States (37.2%) and Brazil (37.5%) than in Europe/Middle East (23.7%) and Australia/New Zealand (15.5%, P<.001). Persistent bacteremia was independently associated with MRSA IE (odds ratio, 6.2; 95% confidence interval, 2.9-13.2). Patients in the United States were most likely to be hemodialysis dependent, to have diabetes, to have a presumed intravascular device source, to receive vancomycin, to be infected with MRSA, and to have persistent bacteremia (P<.001 for all comparisons). CONCLUSIONS: S aureus is the leading cause of IE in many regions of the world. Characteristics of patients with S aureus IE vary significantly by region. Further studies are required to determine the causes of regional variation.

Cross Infection↗

PubMed2005

Bacterial contamination of tissue allografts - experiences of the donor tissue bank of Victoria.

The aim of this study is to report the experience of the Donor Tissue Bank of Victoria with bacteria isolated from musculoskeletal, skin and cardiac allografts retrieved from cadaveric donors. The results of all quality control samples for bacterial culture, taken during retrieval and processing of allografts at the DTBV for a 12 month period, were extracted and analysed. It was found that 15.7% of skin, 15.1% of heart valves and 5.8% of musculoskeletal samples had positive culture results. The number and types of organisms isolated varied with tissue type. The most commonly isolated organisms were Staphylococcus species (including S. aureus). The identity of the isolate and the number of positive specimens from the same donor were considerations in the decision concerning the suitability of tissue for subsequent implantation.

Australia↗

PubMed2004

Surgical-site infection rates and risk factor analysis in coronary artery bypass graft surgery.

BACKGROUND: The Victorian Infection Control Surveillance Project (VICSP) is a multicenter collaborative surveillance project established by infection control practitioners. Five public hospitals contributed data for patients undergoing coronary artery bypass graft (CABG) surgery. OBJECTIVE: To determine the aggregate and comparative interhospital surgical-site infection (SSI) rates for patients undergoing CABG surgery and the risk factors for SSI in this patient group. METHOD: Each institution used standardized definitions of SSI, risk adjustment, and reporting methodology according to the National Nosocomial Infections Surveillance System of the Centers for Disease Control and Prevention. Data on potential risk factors were prospectively collected. RESULTS: For 4,474 patients undergoing CABG surgery, the aggregate SSI rate was 7.8 infections per 100 procedures (95% confidence interval [CI95], 7.0-8.5), with individual institutions ranging between 4.5 and 10.7 infections per 100 procedures. Multivariate risk factor analysis demonstrated age (odds ratio [OR], 1.02; CI95, 1.01-1.04; P < .001), obesity (OR, 1.8; CI95, 1.4-2.3; P < .001), and diabetes mellitus (OR, 1.6; CI95, 1.2-2.1; P < .001) as independent predictors of SSI. Three hundred thirty-four organisms were isolated from 296 SSIs. Of the total SSIs, methicillin-resistant Staphylococcus aureus was isolated from 32%, methicillin-sensitive S. aureus from 24%, gram-negative bacilli (eg, Enterobacter and Escherichia coli) from 18%, and miscellaneous organisms from the remainder. CONCLUSION: We documented aggregate and comparative SSI rates among five Victorian public hospitals performing CABG surgery and defined specific independent risk factors for SSI. VICSP data offer opportunities for targeted interventions to reduce SSI following cardiac surgery.

Adult↗

PubMed2004

Methicillin-resistant Staphylococcus aureus and beyond: what's new in the world of the golden staph?

Methicillin-resistant Staphylococcus aureus (MRSA) continues to plague our hospitals. With the appearance of isolates that are resistant to vancomycin, now, more than ever, we must direct our efforts to controlling its development and spread. New antimicrobials have become available for treatment, but may only be a short-term answer. Our efforts towards control must be directed towards infection control measures such as improved hand hygiene with user-friendly products, such as alcohol-based hand disinfectants. Intranasal mupirocin may have a place in prevention of surgical site infection, although this role has not yet been clearly defined. Other areas where MRSA control may be effected include prudent controlled use of antibiotics, including surgical prophylaxis.

Humans↗

PubMed2003

Current best practices and guidelines. Assessment and management of complications in infective endocarditis.

The most important complications of endocarditis are congestive heart failure, paravalvular abscess formation, and embolism, especially stroke. In addition, endocarditis may be complicated by septic arthritis, vertebral osteomyelitis, pericarditis, metastatic abscesses and an array of renal problems ranging from immune-complex glomerulonephritis to renal abscesses. Adverse reactions associated with medical treatment of endocarditis can also result in significant complications such as ototoxicity and nephrotoxicity, skin rashes, and serum sickness. This review focuses on the cardiac, embolic, neurologic and renal complications of endocarditis and discusses how these complications influence the clinical management of individual cases in daily practice.

Embolism↗

PubMed2003

HCMV DNA detection and quantitation in the plasma and PBL of lung transplant recipients: COBAS Amplicor HCMV monitor test versus in-house quantitative HCMV PCR.

BACKGROUND: Human cytomegalovirus (HCMV) reactivation may cause severe disease in immunosuppressed patients. Quantitation of HCMV viral load in the blood has been shown to be important in predicting for HCMV disease, however the particular blood compartment that should be tested, plasma versus peripheral blood leukocytes (PBL), has been subject to debate. OBJECTIVES: To simultaneously compare HCMV viral loads in the PBL using an in-house quantitative HCMV polymerase chain reaction (PCR) assay and in the plasma using the commercially available COBAS Amplicor HCMV monitor test, in a cohort of lung transplant recipients (LTR). STUDY DESIGN: Sequential paired plasma and PBL samples were collected (n=98) from a total of 21 LTR during the first 6 months post lung transplantation. HCMV viral loads were assessed in the PBL using an in-house quantitative HCMV PCR assay and the plasma using the COBAS Amplicor HCMV monitor test. HCMV disease in LTR was defined as histopathologically proven HCMV pneumonitis. RESULTS: HCMV deoxyribonucleic acid (DNA) was detected in 39/98 (40%) of total samples with excellent agreement between the two strategies. HCMV was detected in both the plasma and PBL in 38/39 (97%) of HCMV positive samples. HCMV viral loads were higher in patients with HCMV pneumonitis in both the PBL and plasma compared to patients without HCMV pneumonitis. Greater than 10-fold increases in HCMV DNA levels had a sensitivity of 88% and a specificity of 73% in the plasma for HCMV pneumonitis and a positive and negative predictive value of 70 and 89%, respectively. Greater that 10-fold increases in HCMV DNA levels in the PBL had a sensitivity of 88% and a specificity of 64%, for HCMV pneumonitis and a positive and negative predictive value of 64 and 88%, respectively. CONCLUSIONS: Acknowledging the difference in assay methods used for HCMV DNA quantitation, the in-house PCR PBL assay and the COBAS Amplicor HCMV monitor plasma assay predicted equally well for HCMV pneumonitis in LTR.

Cytomegalovirus↗

PubMed2003

Acquisition of methicillin-resistant Staphylococcus aureus in a large intensive care unit.

OBJECTIVES: To determine the prevalence of MRSA colonization on admission to the ICU and the incidence of MRSA colonization in the ICU. DESIGN: Prospective cohort study. SETTING: University hospital. PARTICIPANTS: Patients admitted to the ICU in 2000-2001. METHODS: Patients were screened for MRSA with nose, throat, groin, and axilla swabs on admission and discharge. MRSA acquisition was defined as a negative admission screen and a positive discharge screen. Risk factors analyzed included previous wards/current unit, gender, age, and length of stay prior to and in the ICU. Univariate and multivariate analyses were performed using logistic regression. RESULTS: Of screened patients, 6.8% were MRSA colonized on admission to the ICU. Some patients (11.4%) became newly colonized during their stay in the ICU. Factors that remained significant in the multivariate analysis of MRSA colonization on admission were previous admission to various wards and length of stay prior to ICU admission of more than 3 days. In the multivariate analysis of MRSA acquisition in the ICU, being a trauma patient and length of stay in the ICU greater than 2 days remained significant Thirty-six percent of patients had both admission and discharge swabs taken. This percentage increased in the presence of a supervisory nurse. CONCLUSION: Significant acquisition of MRSA occurs in the ICU of our hospital, with trauma patients at increased risk. Patients who had been on the cardiothoracic ward prior to the ICU had a lower risk of MRSA colonization on admission. Presence of a supervisory nurse improved compliance with screening

Adolescent↗

PubMed2003

Use of pulsed-field gel electrophoresis in infection control issues concerning Burkholderia cepacia.

There was concern that nosocomial person-to-person transmission of Burkholderia cepacia had occurred when two patients with cystic fibrosis shared a bathroom. Pulsed-field gel electrophoresis demonstrated that the two isolates were unrelated. Subsequent testing of 34 stored isolates of B. cepacia demonstrated that no particular clone predominated in our hospital.

Burkholderia Infections↗

PubMed2003

Risk factors for new detection of vancomycin-resistant enterococci in acute-care hospitals that employ strict infection control procedures.

Accurate assessment of the risk factors for colonization with vancomycin-resistant enterococci (VRE) among high-risk patients is often confounded by nosocomial VRE transmission. We undertook a 15-month prospective cohort study of adults admitted to high-risk units (hematology, renal, transplant, and intensive care) in three teaching hospitals that used identical strict infection control and isolation procedures for VRE to minimize nosocomial spread. Rectal swab specimens for culture were regularly obtained, and the results were compared with patient demographic factors and antibiotic exposure data. Compliance with screening was defined as "optimal" (100% compliance) or "acceptable" (minor protocol violations were allowed, but a negative rectal swab specimen culture was required within 1 week of becoming colonized with VRE). Colonization with VRE was detected in 1.56% (66 of 4,215) of admissions (0.45% at admission and 0.83% after admission; the acquisition time was uncertain for 0.28%), representing 1.91% of patients. No patients developed infection with VRE. The subsequent rate of new acquisition of VRE was 1.4/1,000 patient days. Renal units had the highest rate (3.23/1,000 patient days; 95% confidence interval [CI], 1.54 to 6.77/1,000 patient days). vanB Enterococcus faecium was the most common species (71%), but other species included vanB Enterococcus faecalis (21%), vanA E. faecium (6%), and vanA E. faecalis (2%). The majority of isolates were nonclonal by pulsed-field gel electrophoresis analysis. Multivariate analysis of risk factors in patients with an acceptable screening suggested that being managed by a renal unit (hazard ratio [HR] compared to the results for patients managed in an intensive care unit, 4.6; 95% CI, 1.2 to 17.0 [P = 0.02]) and recent administration of either ticarcillin-clavulanic acid (HR, 3.6; 95% CI, 1.1 to 11.6 [P = 0.03]) or carbapenems (HR, 2.8; 95% CI, 1.0, 8.0 [P = 0.05]), but not vancomycin or broad-spectrum cephalosporins, were associated with acquisition of VRE. The relatively low rates of colonization with VRE, the polyclonal nature of most isolates, and the possible association with the use of broad-spectrum antibiotics are consistent with either the endogenous emergence of VRE or the amplification of previously undetectable colonization with VRE among high-risk patients managed under conditions in which the risk of nosocomial acquisition was minimized.

Adult↗

PubMed2002

Current best practices and guidelines. Assessment and management of complications in infective endocarditis.

Abscess↗

PubMed2002

Clinical, microbiological, and economic benefit of a change in antibiotic prophylaxis for cardiac surgery.

Vancomycin and rifampicin replaced cephazolin as antibiotic prophylaxis for coronary artery bypass surgery at our institution. Following this intervention, there was a significant decrease (P < .001) in the surgical-site infection rate from 10.5 (95% confidence interval, 8.2 to 13.3) to 4.9 (95% confidence interval, 3.2 to 7.1) infections per 100 procedures. An estimated $576,655 (Australian) was saved between two 12-month periods.

Administration, Oral↗