Cost of bacteraemia caused by methicillin-resistant vs. methicillin-susceptible Staphylococcus aureus in Spain: a retrospective cohort study

A systematic review on the excess health risk of antibiotic-resistant bloodstream infections for six key pathogens in Europe

BACKGROUND

Antimicrobial resistance is a global threat, which requires novel intervention strategies, for which priority pathogens and settings need to be determined.

OBJECTIVES

We evaluated pathogen-specific excess health burden of drug-resistant bloodstream infections (BSIs) in Europe.

METHODS

A systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, and grey literature for the period January 1990 to May 2022.

STUDY ELIGIBILITY CRITERIA

Studies that reported burden data for six key drug-resistant pathogens: carbapenem-resistant (CR) Pseudomonas aeruginosa and Acinetobacter baumannii, third-generation cephalosporin or CR Escherichia coli and Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium. Excess health outcomes compared with drug-susceptible BSIs or uninfected patients. For MRSA and third-generation cephalosporin E. coli and K. pneumoniae BSIs, five or more European studies were identified. For all others, the search was extended to high-income countries.

PARTICIPANTS

Paediatric and adult patients diagnosed with drug-resistant BSI.

INTERVENTIONS

Not applicable.

ASSESSMENT OF RISK OF BIAS

An adapted version of the Joanna-Briggs Institute assessment tool.

METHODS OF DATA SYNTHESIS

Random-effect models were used to pool pathogen-specific burden estimates.

RESULTS

We screened 7154 titles, 1078 full-texts and found 56 studies on BSIs. Most studies compared outcomes of drug-resistant to drug-susceptible BSIs (46/56, 82.1%), and reported mortality (55/56 studies, 98.6%). The pooled crude estimate for excess all-cause mortality of drug-resistant versus drug-susceptible BSIs ranged from OR 1.31 (95% CI 1.03-1.68) for CR P. aeruginosa to OR 3.44 (95% CI 1.62-7.32) for CR K. pneumoniae. Pooled crude estimates comparing mortality to uninfected patients were available for vancomycin-resistant Enterococcus and MRSA BSIs (OR of 11.19 [95% CI 6.92-18.09] and OR 6.18 [95% CI 2.10-18.17], respectively).

CONCLUSIONS

Drug-resistant BSIs are associated with increased mortality, with the magnitude of the effect influenced by pathogen type and comparator. Future research should address crucial knowledge gaps in pathogen- and infection-specific burdens to guide development of novel interventions.

Cost and healthcare utilization of methicillin-resistant Staphylococcus aureus bacteremia estimated from linked antimicrobial resistance surveillance and hospital claims data in Japan

OBJECTIVE

To compare the incremental costs and healthcare utilization of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia with those of methicillin-susceptible S. aureus (MSSA) bacteremia.

DESIGN

Retrospective cohort study using data from April 2014 to March 2015.

SETTING

Antimicrobial resistance surveillance and hospital claims data from 16 Japanese hospitals.

PATIENTS

The study included 73 patients with S. aureus bacteremia: 23 with MRSA and 50 with MSSA.

METHODS

MRSA bacteremia was identified using blood cultures and drug-susceptibility tests. MRSA- and MSSA-related medical practices were evaluated. The costs were calculated and compared. All the medical costs were classified into empirical and definitive therapy periods and expressed in Japanese yen (JPY, 1 USD = 106 JPY). Additionally, costs at aggressive and passive bacterial test-performing facilities were compared.

RESULTS

No significant differences existed in MRSA-related resource use per patient episode between MRSA and MSSA bacteremia during empirical therapy. However, during definitive therapy, in MRSA bacteremia compared with MSSA bacteremia, this difference was higher. The average MRSA-related costs of empirical therapy for MRSA and MSSA were 13,380 and 9,140 JPY (126 and 86 USD) per patient, and for definitive therapy, they were 69,810 and 29,510 JPY (659 and 278 USD) per patient, respectively. No significant differences were noted. Conversely, the average examination costs during definitive therapy differed significantly: 9,740 vs 3,850 JPY (92 vs 36 USD), respectively (P = .0294). Furthermore, the incremental costs in aggressive facilities were lower for the definitive therapy period than those in passive facilities.

CONCLUSIONS

In the definitive therapy period, MRSA bacteremia had higher incremental costs and greater use of healthcare resources. In addition, the incremental costs in aggressive facilities were lower than those in passive facilities.

Evaluation of antibiotic treatment decisions in pediatric intensive care units in Saudi Arabia: A national survey

OBJECTIVE

To describe variables used by Saudi pediatric intensivists to make antibiotic-related decisions for children with suspected severe bacterial infections.

METHODS

We conducted a cross-sectional survey, which was developed using a multi-step methodological approach. The survey included 4 clinical scenarios of the most relevant bacterial infections in pediatric critical care (pneumonia, sepsis, meningitis and intra-abdominal infection). The potential determinants of antibiotic treatment duration addressed in all scenarios included clinical variables (patient characteristics, disease severity), laboratory infection markers, radiologic findings, and pathogens.

RESULTS

The response rate was 65% (55/85). Eight variables (immunodeficiency, 3 months of age, 2 or more organ dysfunctions, Pediatric Risk of Mortality III score >10, leukocytosis, elevated C-reactive protein [CRP], elevated erythrocyte sedimentation rate [ESR], and elevated procalcitonin [PCT]) were associated with prolonging antibiotic treatment duration for all 4 clinical scenarios, with a median increase ranging from 3.0 days (95% confidence interval [CI] 0.5, 3.5, leukocytosis) to 8.8 days (95% CI 5.5, 10.5, immunodeficiency). There were no variables that were consistently associated with shortening antibiotic duration across all scenarios. Lastly, the proportion of physicians who would continue antibiotics for ≥5 days despite a positive viral polymerase chain reaction test result was 67% for pneumonia, 85% for sepsis, 63% for meningitis, and 95% for intra-abdominal infections.

CONCLUSION

Antibiotic-related decisions for critically ill patients are complex and depend on several factors. Saudi pediatric intensivists will use prolonged courses of antibiotics for younger patients, patients with severe clinical picture, and patients with persistently elevated laboratory markers and hospital acquired infections, even when current literature and guidelines do not suggest such practices. Antimicrobial stewardship programs should include interventions to address these misconceptions to ensure the rational use of antibiotics in pediatric intensive care units.

Evaluating antimicrobial appropriateness in a tertiary care pediatric ICU in Saudi Arabia: a retrospective cohort study

Background

Inappropriate antibiotic utilization is associated with the emergence of antimicrobial resistance (AMR) and a decline in antibiotic susceptibility in many pathogenic organisms isolated in intensive care units. Antibiotic stewardship programs (ASPs) have been recommended as a strategy to reduce and delay the impact of AMR. A crucial step in ASPs is understanding antibiotic utilization practices and quantifying the problem of inappropriate antibiotic use to support a targeted solution. We aim to characterize antibiotic utilization and determine the appropriateness of antibiotic prescription in a tertiary care pediatric intensive care unit.

Methods

A retrospective cohort study was conducted at King Abdullah Specialized Children’s Hospital, Riyadh, Saudi Arabia, over a 6-month period. Days of therapy (DOT) and DOT per 1000 patient-days were used as measures of antibiotic consumption. The appropriateness of antibiotic use was assessed by two independent pediatric infectious disease physicians based on the Centers for Disease Control and Prevention 12-step Campaign to prevent antimicrobial resistance among hospitalized children.

Results

During the study period, 497 patients were admitted to the PICU, accounting for 3009 patient-days. A total of 274 antibiotic courses were administered over 2553 antibiotic days. Forty-eight percent of antibiotic courses were found to be nonadherent to at least 1 CDC step. The top reasons were inappropriate antibiotic choice (empirical or definitive) and inappropriate prophylaxis durations. Cefazolin and vancomycin contributed to the highest percentage of inappropriate DOTs.

Conclusions

Antibiotic consumption was high with significant inappropriate utilization. These data could inform decision-making in antimicrobial stewardship programs and strategies. The CDC steps provide a more objective tool and limit biases when assessing antibiotic appropriateness

Clinical and economic impact of methicillin-resistant Staphylococcus aureus: a multicentre study in China

Methicillin-resistant Staphylococcus aureus (MRSA) has become a serious threat to global health. In China, the proportion of S. aureus isolates that were MRSA was 44.6% in 2014. The clinical and economic impact of MRSA in China remains largely uninvestigated. This study aims to compare the differences in hospital costs, length of hospital stay, and hospital mortality rate between MRSA and methicillin-susceptible S. aureus (MSSA) colonization or infection and between MRSA cases and those without an S. aureus infection. A retrospective and multicentre study was conducted in four tertiary hospitals in China between 2013 and 2015. Inpatient characteristics and hospital costs were collected from electronic medical records. We conducted propensity score matching (PSM) to eliminate selection bias by balancing the potential confounding variables between the two groups. The main indicators included hospital costs, length of hospital stay, and hospital mortality rate. A total of 1,335 inpatients with MRSA, 1,397 with MSSA, and 33,606 without an S. aureus infection were included. PSM obtained 954 and 1,313 pairs between the MRSA and MSSA groups and between the MRSA and S. aureus-free groups, respectively. After PSM, MRSA colonization or infection is associated with an increased total hospital cost ranging from $3,220 to $9,606, an excess length of hospital stay of 6 days–14 days, and an attributable hospital mortality rate of 0–3.58%. Between the MRSA and MSSA groups, MRSA colonization or infection was significantly associated with a higher total hospital cost and longer length of hospital stay among survivors but not among non-survivors; however, there were no differences in the hospital mortality rate between these two groups. Between the MRSA and the S. aureus-free groups, MRSA colonization or infection was significantly associated with an increased total hospital cost, a prolonged length of hospital stay and a higher hospital mortality rate among both survivors and non-survivors. It is critical to quantify the clinical and economic impact of MRSA to justify resource allocation for the development of strategies to improve clinical outcomes and to reduce the economic burden.

Reevaluation of the impact of methicillin-resistance on outcomes in patients with Staphylococcus aureus bacteremia and endocarditis

BACKGROUND/AIMS

Methicillin-resistant Staphylococcus aureus (MRSA) is highly prevalent in hospitals, and has recently emerged in the community. The impact of methicillin-resistance on mortality and medical costs for patients with S. aureus bacteremia (SAB) requires reevaluation.

METHODS

We searched studies with SAB or endocarditis using electronic databases including Ovid-Medline, Embase-Medline, and Cochrane Library, as well as five local databases for published studies during the period January 2000 to September 2011.

RESULTS

A total of 2,841 studies were identified, 62 of which involved 17,563 adult subjects and were selected as eligible. A significant increase in overall mortality associated with MRSA, compared to that with methicillin-susceptible S. aureus (MSSA), was evidenced by an odds ratio (OR) of 1.95 (95% confidence interval [CI], 1.73 to 2.21; p < 0.01). In 13 endocarditis studies, MRSA increased the risk of mortality, with an OR of 2.65 (95% CI, 1.46 to 4.80). When three studies, which compared mortality rates between CA-MRSA and CA-MSSA, were combined, the risk of methicillin-resistance increased 3.23-fold compared to MSSA (95% CI, 1.25 to 8.34). The length of hospital stay in the MRSA group was 10 days longer than that in the MSSA group (95% CI, 3.36 to 16.70). Of six studies that reported medical costs, two were included in the analysis, which estimated medical costs to be $9,954.58 (95% CI, 8,951.99 to 10,957.17).

CONCLUSION

MRSA is still associated with increased mortality, longer hospital stays and medical costs, compared with MSSA in SAB in studies published since the year 2000.

Economic burden of antibiotic resistance in ESKAPE organisms: a systematic review

Background

Antibiotic resistance (ABR) is one of the biggest threats to global health. Infections by ESKAPE (Enterococcus, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. coli) organisms are the leading cause of healthcare-acquired infections worldwide. ABR in ESKAPE organisms is usually associated with significant higher morbidity, mortality, as well as economic burden. Directing attention towards the ESKAPE organisms can help us to better combat the wide challenge of ABR, especially multi-drug resistance (MDR).

Objective

This study aims to systematically review and evaluate the evidence of the economic consequences of ABR or MDR ESKAPE organisms compared with susceptible cases or control patients without infection/colonization in order to determine the impact of ABR on economic burden.

Methods

Both English-language databases and Chinese-language databases up to 16 January, 2019 were searched to identify relevant studies assessing the economic burden of ABR. Studies reported hospital costs (charges) or antibiotic cost during the entire hospitalization and during the period before/after culture among patients with ABR or MDR ESKAPE organisms were included. The costs were converted into 2015 United States Dollars. Disagreements were resolved by a third reviewer.

Results

Of 13,693 studies identified, 83 eligible studies were included in our review. The most studied organism was S. aureus, followed by Enterococcus, A. baumannii, E. coli, E. coli or/and K. pneumoniae, P. aeruginosa, and K. pneumoniae. There were 71 studies on total hospital cost or charge, 12 on antibiotic cost, 11 on hospital cost or charge after culture, 4 on ICU cost, 2 on hospital cost or charge before culture, and 2 on total direct and indirect cost. In general, ABR or MDR ESKAPE organisms are significantly associated with higher economic burden than those with susceptible organisms or those without infection or colonization. Nonetheless, there were no differences in a few studies between the two groups on total hospital cost or charge (16 studies), antibiotic cost (one study), hospital cost before culture (one study), hospital cost after culture (one study). Even, one reported that costs associated with MSSA infection were higher than the costs for similar MRSA cases.

Conclusions

ABR in ESKAPE organisms is not always, but usually, associated with significantly higher economic burden. The results without significant differences may lack statistical power to detect a significant association. In addition, study design which controls for severity of illness and same empirical antibiotic therapy in the two groups would be expected to bias the study towards a similar, even negative result. The review also highlights key areas where further research is needed.

Impact of Early Cannulation Grafts on Quality and Cost of Care for Patients With End-Stage Renal Disease

BACKGROUND

The annual cost of care associated with end-stage renal disease (ESRD) per patient on hemodialysis is approaching $100,000, with nearly $42 billion in national spend per year. Early cannulation arteriovenous grafts (ECAVGs) help decrease the use of central venous catheters (CVCs), thus potentially decreasing the cost of care. However, a formal financial analysis that also includes the cost of CVC-related complications and secondary interventions has not been completed. The purpose of this project is to evaluate the overall financial costs associated with ECAVGs on patients with ESRD during a one-year period.

METHODS

Access modality, complications, secondary interventions, hospital outcomes, and cost of care were determined for 397 sequential patients who underwent access creation between July 2014 and October 2018. A detailed financial analysis was completed, including an evaluation of implant, supplies, medications, laboratories, labor, and other direct costs. All variables were measured at the time of the index procedure, 30 days, 90 days, 180 days, 270 days, and one year.

RESULTS

There were 131 patients who underwent arteriovenous fistula (AVF) and 266 who underwent ECAVG for dialysis access. The average cost of care was $17,523 for AVF and $5,894 for ECAVG at one year (P < 0.01). Fewer CVC-related complications and secondary interventions associated with ECAVGs saved $11,630 per patient with ESRD, primarily in the form of supply costs. Fewer CVCs in the patients receiving ECAVGs led to an additional $1,083 decrease in cost associated with sepsis reduction at one year. A subsequent decrease in length of stay and ICU utilization led to an additional $2.0 million decrease in annual cost of care for patients with ESRD.

CONCLUSIONS

The use of ECAVGs has significant cost savings over using an AVF and CVC for urgent-start dialysis in patients with ESRD. This cost savings is secondary to decreased CVC-related complications and fewer secondary interventions. Significant national savings are possible with appropriate use of ECAVGs in patients with ESRD.

Patterns of cross-resistance and collateral sensitivity between clinical antibiotics and natural antimicrobials

Bacteria interact with a multitude of other organisms, many of which produce antimicrobials. Selection for resistance to these antimicrobials has the potential to result in resistance to clinical antibiotics when active compounds target the same bacterial pathways. The possibility of such cross-resistance between natural antimicrobials and antibiotics has to our knowledge received very little attention. The antimicrobial activity of extracts from seaweeds, known to be prolific producers of antimicrobials, is here tested against Staphylococcus aureus isolates with varied clinical antibiotic resistance profiles. An overall effect consistent with cross-resistance is demonstrated, with multidrug-resistant S. aureus strains being on average more resistant to seaweed extracts. This pattern could potentially indicate that evolution of resistance to antimicrobials in the natural environment could lead to resistance against clinical antibiotics. However, patterns of antimicrobial activity of individual seaweed extracts vary considerably and include collateral sensitivity, where increased resistance to a particular antibiotic is associated with decreased resistance to a particular seaweed extract. Our correlation-based methods allow the identification of antimicrobial extracts bearing most promise for downstream active compound identification and pharmacological testing.

Staphylococcus aureus bloodstream infections in Latin America: results of a multinational prospective cohort study

Background

Substantial heterogeneity in the epidemiology and management of Staphylococcus aureus bacteraemia (SAB) occurs in Latin America. We conducted a prospective cohort study in 24 hospitals from nine Latin American countries.

Objectives

To assess the clinical impact of SAB in Latin America.

Patients and methods

We evaluated differences in the 30 day attributable mortality among patients with SAB due to MRSA compared with MSSA involving 84 days of follow-up. Adjusted relative risks were calculated using a generalized linear model.

Results

A total of 1030 patients were included. MRSA accounted for 44.7% of cases with a heterogeneous geographical distribution. MRSA infection was associated with higher 30 day attributable mortality [25% (78 of 312) versus 13.2% (48 of 363), adjusted RR: 1.94, 95% CI: 1.38-2.73, P < 0.001] compared with MSSA in the multivariable analysis based on investigators' assessment, but not in a per-protocol analysis [13% (35 of 270) versus 8.1% (28 of 347), adjusted RR: 1.10, 95% CI: 0.75-1.60, P = 0.616] or in a sensitivity analysis using 30 day all-cause mortality [36% (132 of 367) versus 27.8% (123 of 442), adjusted RR: 1.09, 95% CI: 0.96-1.23, P = 0.179]. MRSA infection was not associated with increased length of hospital stay. Only 49% of MSSA bloodstream infections (BSI) received treatment with β-lactams, but appropriate definitive treatment was not associated with lower mortality (adjusted RR: 0.93, 95% CI: 0.70-1.23, P = 0.602).

Conclusions

MRSA-BSIs in Latin America are not associated with higher 30 day mortality or longer length of stay compared with MSSA. Management of MSSA-BSIs was not optimal, but appropriate definitive therapy did not appear to influence mortality.

Disease Burden, Characteristics, and Outcomes of Methicillin-Resistant Staphylococcus aureus Bloodstream Infection in Hong Kong

We aimed to describe disease burden, characteristics, and outcomes of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) in Hong Kong. A retrospective, observational study was conducted in 26 Hong Kong public hospitals between January 2010 and December 2012. The primary outcome measures were 30-day mortality rate and infection-related hospital cost. Of 1133 patients reviewed, 727 (64.17%) were male, 1075 (94.88%) had health care-associated community-onset and 44 (3.88%) had hospital-onset MRSA infection. The mean age of patients was 76 (SD = 15) years, including 172 (15.18%) aged 20 to 59 years and 961 (84.8%) aged ≥60 years. The annual incidence rates in age groups of 20 to 59 years and ≥60 years were 0.96 to 1.148 per 100 000 and 22.7 to 24.8 per 100 000, respectively. The 30-day mortality was 367 (32.39%). Older patients (>79 years), chronic lung disease, and prior hospitalization were associated with increased mortality. The mean cost was US$10 565 (SD = 11 649; US$1 = HK$7.8). MRSA BSI was a significant burden in Hong Kong.

Cost Attributable to Nosocomial Bacteremia. Analysis According to Microorganism and Antimicrobial Sensitivity in a University Hospital in Barcelona

AIM

To calculate the incremental cost of nosocomial bacteremia caused by the most common organisms, classified by their antimicrobial susceptibility.

METHODS

We selected patients who developed nosocomial bacteremia caused by Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, or Pseudomonas aeruginosa. These microorganisms were analyzed because of their high prevalence and they frequently present multidrug resistance. A control group consisted of patients classified within the same all-patient refined-diagnosis related group without bacteremia. Our hospital has an established cost accounting system (full-costing) that uses activity-based criteria to analyze cost distribution. A logistic regression model was fitted to estimate the probability of developing bacteremia for each admission (propensity score) and was used for propensity score matching adjustment. Subsequently, the propensity score was included in an econometric model to adjust the incremental cost of patients who developed bacteremia, as well as differences in this cost, depending on whether the microorganism was multidrug-resistant or multidrug-sensitive.

RESULTS

A total of 571 admissions with bacteremia matched the inclusion criteria and 82,022 were included in the control group. The mean cost was € 25,891 for admissions with bacteremia and € 6,750 for those without bacteremia. The mean incremental cost was estimated at € 15,151 (CI, € 11,570 to € 18,733). Multidrug-resistant P. aeruginosa bacteremia had the highest mean incremental cost, € 44,709 (CI, € 34,559 to € 54,859). Antimicrobial-susceptible E. coli nosocomial bacteremia had the lowest mean incremental cost, € 10,481 (CI, € 8,752 to € 12,210). Despite their lower cost, episodes of antimicrobial-susceptible E. coli nosocomial bacteremia had a major impact due to their high frequency.

CONCLUSIONS

Adjustment of hospital cost according to the organism causing bacteremia and antibiotic sensitivity could improve prevention strategies and allow their prioritization according to their overall impact and costs. Infection reduction is a strategy to reduce resistance.

Antimicrobial susceptibility among important pathogens collected as part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) in Spain, 2004-2014

Here we report in vitro activity data from the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) for tigecycline and comparators against Gram-positive and Gram-negative organisms collected from 27 medical centres in Spain between 2004 and 2014. Minimum inhibitory concentrations (MICs) were determined according to the broth microdilution methodology of the Clinical and Laboratory Standards Institute (CLSI) and susceptibility were determined according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) interpretive criteria. Susceptibility was >97% for all antimicrobials tested against Enterococcus faecalis, and >98% of Enterococcus faecium tested were susceptible to tigecycline, linezolid and vancomycin. A total of 34.1% (1071/3143) of Staphylococcus aureus were meticillin-resistant S. aureus (MRSA), and all MRSA were susceptible to tigecycline and vancomycin. Among the Streptococcus pneumoniae, 5.2% (74/1430) were penicillin-resistant and all isolates were susceptible to linezolid and vancomycin. Among the Enterobacteriaceae, 17.1% (542/3167) of Escherichia coli, 2.8% (19/682) of Klebsiella oxytoca and 19.0% (441/2327) of Klebsiella pneumoniae isolates produced extend-spectrum β-lactamases (ESBLs). Against ESBL-producing E. coli and K. pneumoniae, susceptibility was highest for meropenem, amikacin and tigecycline with rates of >92% and >80%, respectively. Among the Acinetobacter baumannii, susceptibility ranged between 23.5% for levofloxacin and 51.4% for amikacin, and an MIC90 of 2mg/L was observed for tigecycline. In conclusion, monitoring of antimicrobial susceptibility among organisms such as S. aureus, Enterobacteriaceae and A. baumannii is of continuing importance as a guide to clinicians. Depending on the organism to be treated, carbapenems, linezolid, vancomycin and tigecycline continue to be active in Spain.

Cost Analysis of an Intervention to Prevent Methicillin-Resistant Staphylococcus Aureus (MRSA) Transmission

INTRODUCTION

Our objective was to assess the cost implications of a vertical MRSA prevention program that led to a reduction in MRSA bacteremia.

METHODS

We performed a matched historical cohort study and cost analysis in a single hospital in Israel for the years 2005-2011. The cost of MRSA bacteremia was calculated as total hospital cost for patients admitted with bacteremia and for patients with hospital-acquired bacteremia, the difference in cost compared to matched controls. The cost of prevention was calculated as the sum of the cost of microbiology tests, single-use equipment used for patients in isolation, and infection control personnel.

RESULTS

An average of 20,000 patients were screened yearly. The cost of prevention was $208,100 per year, with the major contributor being laboratory cost. We calculated that our intervention averted 34 cases of bacteremia yearly: 17 presenting on admission and 17 acquired in the hospital. The average cost of a case admitted with bacteremia was $14,500, and the net cost attributable to nosocomial bacteremia was $9,400. Antibiotics contributed only 0.4% of the total disease management cost. When the annual cost of averted cases of bacteremia and that of prevention were compared, the intervention resulted in annual cost savings of $199,600.

CONCLUSIONS

A vertical MRSA prevention program targeted at high-risk patients, which was highly effective in preventing bacteremia, is cost saving. These results suggest that allocating resources to targeted prevention efforts might be beneficial even in a single institution in a high incidence country.

Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) at ambient freshwater beaches

Methicillin-resistant Staphylococcus aureus (MRSA) are a threat to human health worldwide, and although detected at marine beaches, they have been largely unstudied at freshwater beaches. Genes indicating S. aureus (SA; femA) and methicillin resistance (mecA) were detected at 11 and 12 of 13 US Great Lakes beaches and in 18% or 27% of 287 recreational water samples, respectively. Eight beaches had mecA+femA (potential MRSA) detections. During an intensive study, higher bather numbers, staphylococci concentrations, and femA detections were found in samples collected after noon than before noon. Local population density, beach cloud cover, and beach wave height were significantly correlated with SA or MRSA detection frequency. The Panton-Valentine leukocidin gene, associated with community-acquired MRSA, was detected in 12 out of 27 potential MRSA samples. The femA gene was detected less frequently at beaches that met US enterococci criteria or EU enterococci 'excellent' recreational water quality, but was not related to Escherichia coli-defined criteria. Escherichia coli is often the only indicator used to determine water quality at US beaches, given the economic and healthcare burden that can be associated with infections caused by SA and MRSA, monitoring of recreational waters for non-fecal bacteria such as staphylococci and/or SA may be warranted.

Economic features of antibiotic resistance: the case of methicillin-resistant Staphylococcus aureus

This paper analyses and updates the economic information regarding methicillin-resistant Staphylococcus aureus (MRSA), including information that has been previously reviewed by other authors, and new information, for the purpose of facilitating health management and clinical decisions. The analysed articles reveal great disparity in the economic burden on MRSA patients; this is mainly due to the diversity of the designs of the studies, as well as the variability of the patients and the differences in health care systems. Regarding prophylactic strategies, the studies do not provide conclusive results that could unambiguously orientate health management. The studies addressing treatments noted that linezolid seems to be a cost-effective treatment for MRSA, mostly because it is associated with a shorter length of stay (LOS) in hospital. However, important variables such as antimicrobial susceptibility, infection type and resistance emergence should be included in these analyses before a conclusion is reached regarding which treatment is the best (most efficient). The reviewed studies found that rapid MRSA detection, using molecular techniques, is an efficient technique to control MRSA. As a general conclusion, the management of MRSA infections implicates important economic costs for hospitals, as they result in higher direct costs and longer LOS than those related to methicillin-susceptible S. aureus (MSSA) patients or MRSA-free patients; there is wide variability in those increased costs, depending on different variables. Moreover, the research reveals a lack of studies on other related topics, such as the economic implications of changes in MRSA epidemiology (community patients and lineages associated with farm animals).

Infections, antibiotic treatment and mortality in patients admitted to ICUs in countries considered to have high levels of antibiotic resistance compared to those with low levels

Background

Antimicrobial resistance is an increasing concern in ICUs worldwide. Infection with an antibiotic resistant (ABR) strain of an organism is associated with greater mortality than infection with the non-resistant strain, but there are few data assessing whether being admitted to an intensive care unit (ICU) with high levels of antimicrobial resistance is associated with a worse outcome than being admitted to an ICU with low rates of resistance. The aim of this study was, therefore, to compare the characteristics of infections and antibiotic treatments and patient outcomes in patients admitted to ICUs in countries considered as having high levels of antibiotic resistance and those admitted to ICUs in countries considered as having low levels of antibiotic resistance.

Methods

Data from the large, international EPIC II one-day point prevalence study on infections in patients hospitalized in ICUs were used. For the current study, we compared the data obtained from patients from two groups of countries: countries with reported MRSA rates of ≥ 25% (highABR: Greece, Israel, Italy, Malta, Portugal, Spain, and Turkey) and countries with MRSA rates of < 5% (lowABR: Denmark, Finland, Netherlands, Norway, and Sweden).

Results

On the study day, 1187/2204 (53.9%) patients in the HighABR ICUs were infected and 255/558 (45.7%) in the LowABR ICUs (P < 0.01). Patients in the HighABR ICUs were more severely ill than those in the LowABR ICUs, as reflected by a higher SAPS II score (35.6 vs 32.7, P < 0.05) and had longer median ICU (12 days vs 5 days) and hospital (24 days vs 16 days) lengths of stay. They also had higher crude ICU (20.0% vs 15.4%) and hospital (27.0% vs 21.5%) mortality rates (both P < 0.05). However, after multivariable adjustment and matched pair analysis there were no differences in ICU or hospital mortality rates between High or LowABR ICU patients overall or among those with infections.

Conclusions

Being hospitalized in an ICU in a region with high levels of antimicrobial resistance is not associated per se with a worse outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-513) contains supplementary material, which is available to authorized users.

Daily bathing with chlorhexidine-based soap and the prevention of Staphylococcus aureus transmission and infection

OBJECTIVE

Determine whether daily bathing with chlorhexidine-based soap decreased methicillin-resistant Staphylococcus aureus (MRSA) transmission and intensive care unit (ICU)-acquired S. aureus infection among ICU patients.

DESIGN

Prospective pre-post-intervention study with control unit.

SETTING

A 1,250-bed tertiary care teaching hospital.

PATIENTS

Medical and surgical ICU patients.

METHODS

Active surveillance for MRSA colonization was performed in both ICUs. In June 2005, a chlorhexidine bathing protocol was implemented in the surgical ICU. Changes in S. aureus transmission and infection rate before and after implementation were analyzed using time-series methodology.

RESULTS

The intervention unit had a 20.68% decrease in MRSA acquisition after institution of the bathing protocol (12.64 cases per 1,000 patient-days at risk before the intervention vs 10.03 cases per 1,000 patient-days at risk after the intervention; β, -2.62 [95% confidence interval (CI), -5.19 to -0.04]; P = .046). There was no significant change in MRSA acquisition in the control ICU during the study period (10.97 cases per 1,000 patient-days at risk before June 2005 vs 11.33 cases per 1,000 patient-days at risk after June 2005; β, -11.10 [95% CI, -37.40 to 15.19]; P = .40). There was a 20.77% decrease in all S. aureus (including MRSA) acquisition in the intervention ICU from 2002 through 2007 (19.73 cases per 1,000 patient-days at risk before the intervention to 15.63 cases per 1,000 patient-days at risk after the intervention [95% CI, -7.25 to -0.95]; P = .012)]. The incidence of ICU-acquired MRSA infections decreased by 41.37% in the intervention ICU (1.96 infections per 1,000 patient-days at risk before the intervention vs 1.15 infections per 1,000 patient-days at risk after the intervention; P = .001).

CONCLUSIONS

Institution of daily chlorhexidine bathing in an ICU resulted in a decrease in the transmission of S. aureus, including MRSA. These data support the use of routine daily chlorhexidine baths to decrease rates of S. aureus transmission and infection.

Combined use of the BinaxNOW Staphylococcus aureus test with the Clearview PBP2a assay for the early detection of methicillin-resistant S. aureus from positive blood cultures

The use of combination 2 novel immunochromatographic assays for same-day detection of methicillin-resistant Staphylococcus aureus (MRSA) from positive blood cultures was evaluated. Compared to the standard culture methods, the BinaxNOW® S. aureus test demonstrated 98.7% sensitivity and 100% specificity in correctly identifying S. aureus. The sensitivity and specificity of the Clearview® PBP2a assay in differentiating MRSA from methicillin-susceptible S. aureus were 97.1% and 100%.

Impact of antimicrobial multidrug resistance on inpatient care cost: an evaluation of the evidence

This article evaluates the in-hospital costs attributable to antimicrobial multidrug resistance, defined as the difference in averaged costs of the patients infected with a multidrug-resistant (MDR) versus a non-MDR organism. PubMed and Scopus databases were searched to identify relevant studies. Twenty four studies were included: four on carbapenem-resistant or MDR Gram negative nonfermenters, eight on extended-spectrum b-lactamase-producing Enterobacteriaceae and 12 on methicillin-resistant Staphylococcus aureus. In two studies on carbapenem-resistant nonfermenters, the attributable mean hospital charges were US$58,457 and 85,299, respectively. The attributable mean total costs were US$4484 in a study referring to MDR Acinetobacter baumannii, while that varied from US$1584 to 30,093 among studies on extended-spectrum b-lactamase-producing Enterobacteriaceae. With respect to methicillin-resistant S. aureus, the attributable mean total costs varied from US$1014 to 40,090. The in-hospital costs attributable to multidrug resistance are alarmingly high, justifying the application of strict infection control measures in medical institutions with increased rate of MDR infections.

Controlled multicenter evaluation of a bacteriophage-based method for rapid detection of Staphylococcus aureus in positive blood cultures

Staphylococci are a frequent cause of bloodstream infections (BSIs). Appropriate antibiotic treatment for BSIs may be delayed because conventional laboratory testing methods take 48 to 72 h to identify and characterize isolates from positive blood cultures. We evaluated a novel assay based on bacteriophage amplification that identifies Staphylococcus aureus and differentiates between methicillin-susceptible and methicillin-resistant S. aureus (MSSA and MRSA, respectively) in samples taken directly from signal-positive Bactec blood culture bottles within 24 h of positive signal, with results available within 5 h. The performance of the MicroPhage KeyPath MRSA/MSSA blood culture test was compared to conventional identification and susceptibility testing methods. At four sites, we collectively tested a total of 1,165 specimens, of which 1,116 were included in our analysis. Compared to standard methods, the KeyPath MRSA/MSSA blood culture test demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 91.8%, 98.3%, 96.3%, and 96.1%, respectively, for correctly identifying S. aureus. Of those correctly identified as S. aureus (n = 334), 99.1% were correctly categorized as either MSSA or MRSA. Analysis of a subset of the data revealed that the KeyPath MRSA/MSSA blood culture test delivered results a median of 30 h sooner than conventional methods (a median of 46.9 h versus a median of 16.9 h). Although the sensitivity of the test in detecting S. aureus-positive samples is not high, its accuracy in determining methicillin resistance and susceptibility among positives is very high. These characteristics may enable earlier implementation of appropriate antibiotic treatment for many S. aureus BSI patients.

Impact of acute kidney injury on mortality and medical costs in patients with meticillin-resistant Staphylococcus aureus bacteraemia: a retrospective, multicentre observational study

BACKGROUND

Despite the frequent occurrence of acute kidney injury (AKI) associated with meticillin-resistant Staphylococcus aureus (MRSA) infection during treatment, the adverse impact of renal injury on clinical and economic outcomes has not been evaluated.

AIM

To study the clinical and economic burdens of MRSA bacteraemia and the impact of AKI occurring during treatment on outcomes.

METHODS

Medical records of patients hospitalized for MRSA bacteraemia between March 2010 and February 2011 in eight hospitals in Korea were reviewed retrospectively to evaluate the risk factors for AKI and mortality. Direct medical costs per patient of MRSA bacteraemia during treatment were estimated from the medical resources consumed.

FINDINGS

In all, 335 patients were identified to have MRSA bacteraemia. AKI occurred in 135 patients (40.3%) during first-line antibiotic therapy. Independent risk factors for AKI were male sex, underlying renal disease, intra-abdominal and central venous catheter infection, and increase in Pitt bacteraemia score. Seventy-seven (23.0%) patients died during the study period. Underlying solid tumour, high Pitt bacteraemia score, and occurrence of AKI were independent risk factors for mortality. The mean total medical cost per MRSA patient was estimated as South Korean Won 5,435,361 (US$4,906), and occurrence of AKI and ICU admission were identified as independent predictors of increased direct medical costs. Compared with patients who retained their baseline renal function, patients with AKI had a 45% increase in medical costs.

CONCLUSIONS

Patients who developed AKI showed significantly higher mortality rate and greater direct medical costs compared with patients who retained baseline renal function.

Healthcare-associated Staphylococcus aureus bloodstream infection: length of stay, attributable mortality, and additional direct costs

This study aimed to determine the excess length of stay, extra expenditures, and attributable mortality to healthcare-associated S. aureus bloodstream infection (BSI) at a teaching hospital in central Brazil. The study design was a matched (1:1) case-control. Cases were defined as patients >13 years old, with a healthcare-associated S. aureus BSI. Controls included patients without an S. aureus BSI, who were matched to cases by gender, age (± 7 years), morbidity, and underlying disease. Data were collected from medical records and from the Brazilian National Hospital Information System (Sistema de Informações Hospitalares do Sistema Único de Saúde - SIH/SUS). A Wilcoxon rank sum test was performed to compare length of stay and costs between cases and controls. Differences in mortality between cases and controls were compared using McNemar's tests. The Mantel-Haenzel stratified analysis was performed to compare invasive device utilization. Data analyses were conducted using Epi Info 6.0 and Statistical Package for Social Sciences (SPSS 13.0). 84 case-control pairs matched by gender, age, admission period, morbidity, and underlying disease were analyzed. The mean lengths of hospital stay were 48.3 and 16.2 days for cases and controls, respectively (p<0.01), yielding an excess hospital stay among cases of 32.1 days. The excess mortality among cases compared to controls that was attributable to S. aureus bloodstream infection was 45.2%. Cases had a higher risk of dying compared to controls (OR 7.3, 95% CI 3.1-21.1). Overall costs of hospitalization (SIH/SUS) reached US$ 123,065 for cases versus US$ 40,247 for controls (p<0.01). The cost of antimicrobial therapy was 6.7 fold higher for cases compared to controls. Healthcare-associated S. aureus BSI was associated with statistically significant increases in length of hospitalization, attributable mortality, and economic burden. Implementation of measures to minimize the risk of healthcare-associated bacterial infections is essential.

Costs of healthcare- and community-associated infections with antimicrobial-resistant versus antimicrobial-susceptible organisms

OBJECTIVE

We compared differences in the hospital charges, length of hospital stay, and mortality between patients with healthcare- and community-associated bloodstream infections, urinary tract infections, and pneumonia due to antimicrobial-resistant versus -susceptible bacterial strains.

METHODS

A retrospective analysis of an electronic database compiled from laboratory, pharmacy, surgery, financial, and patient location and device utilization sources was undertaken on 5699 inpatients who developed healthcare- or community-associated infections between 2006 and 2008 from 4 hospitals (1 community, 1 pediatric, 2 tertiary/quaternary care) in Manhattan. The main outcome measures were hospital charges, length of stay, and mortality among patients with antimicrobial-resistant and -susceptible infections caused by Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii.

RESULTS

Controlling for multiple confounders using linear regression and nearest neighbor matching based on propensity score estimates, resistant healthcare- and community-associated infections, when compared with susceptible strains of the same organism, were associated with significantly higher charges ($15,626; confidence interval [CI], $4339-$26,913 and $25,573; CI, $9331-$41,816, respectively) and longer hospital stays for community-associated infections (3.3; CI, 1.5-5.4). Patients with resistant healthcare-associated infections also had a significantly higher death rate (0.04; CI, 0.01-0.08).

CONCLUSIONS

With careful matching of patients infected with the same organism, antimicrobial resistance was associated with higher charges, length of stay, and death rates. The difference in estimates after accounting for censoring for death highlight divergent social and hospital incentives in reducing patient risk for antimicrobial resistant infections.

Optimizing delivery of care for patients with MRSA infection: focus on transitions of care

Staphylococcus aureus is among the most prevalent pathogens isolated from hospitalized patients; those infected with methicillin-resistant strains have longer hospital stays and higher total costs compared with those infected by methicillin-susceptible strains. A multidisciplinary team of health care providers, including hospitalists and other hospital-based physicians, clinical pharmacists, infectious disease specialists, infection control professionals, and case managers, is key to improving treatment and outcomes in these patients. Optimizing transitions of care for hospitalized patients with S aureus infections can improve quality and reduce total costs of care. Hospital length of stay can be shortened by initiating timely, appropriate empiric therapy and by transitioning suitable patients to outpatient antimicrobial therapy. The number of hospitalizations can be reduced by identifying patients who are suitable candidates for initial outpatient antimicrobial therapy. Consistent with good antimicrobial stewardship, the risk of resistance can be minimized by de-escalating empiric therapy to a more narrow-spectrum agent once culture and susceptibility testing results are known. There are several antimicrobial agents available for the management of S aureus infections, including methicillin-resistant S aureus. Consideration of these agents' characteristics may facilitate optimal transition of patients through health care settings.

Pharmaco-economic evaluation of antibiotic therapy strategies in DRG-based healthcare systems - a new approach

The cost of treatments especially in conditions where multiresistant bacteria are involved are a major issue in times where in most developed countries in the world payment systems based on diagnoses-related-groups (DRG) are in place. There is great evidence that especially the length of stay in hospital (LOS), the time in the intensive care unit (ICU-days) and the hours of mechanical ventilation (HMV) are major cost drivers.

While established methods of pharmacoeconomical analyses focus on the efficiency of drugs from healthcare system perspective, these data are often not sufficient for improving treatment strategies in a given hospital context.

We developed a system that allows the analysis of patients with severe infections on the basis of routine data that is also used for reimbursement. These data contain a lot of information concerning the clinical conditions. By using the ICD-coding we developed an algorithm which allows the detection of patients with infections and gives information on the potential financial outcome of these patients. By using the analysis it is possible to identify subsets of infections and the patient records that had a potentially negative DRG-result, i.e. the costs are higher than the reimbursement. When identified the patient records undergo a peer review, where the clinical situation and the antibiotic therapy are reviewed by medical experts. In case simulations it is possible to find out if a different therapeutic approach, e.g. by different choices in initial (empirical) antibiotic treatment would have caused other outcomes.

Data driven analyses together with peer reviews of patient records are a useful tool to examine antibiotic treatment strategies and to establish changes that again can be reviewed on a regular basis. Doing this a continous improvement process can be established in hospitals which can lead to a better balance of clinical and economical outcomes in patients with severe infections. Moreover these analyses are helpful in assessing the literature on economical benefits of new therapies.