Effects of the COVID-19 Pandemic on Incidence and Epidemiology of Catheter-Related Bacteremia, Spain.

We compared hospital-acquired catheter-related bacteremia (CRB) episodes diagnosed at acute care hospitals in Catalonia, Spain, during the COVID-19 pandemic in 2020 with those detected during 2007-2019. We compared the annual observed and predicted CRB rates by using the negative binomial regression model and calculated stratified annual root mean squared errors. A total of 10,030 episodes were diagnosed during 2007-2020. During 2020, the observed CRB incidence rate was 0.29/103 patient-days, whereas the predicted CRB rate was 0.14/103 patient-days. The root mean squared error was 0.153. Thus, a substantial increase in hospital-acquired CRB cases was observed during the COVID-19 pandemic in 2020 compared with the rate predicted from 2007-2019. The incidence rate was expected to increase by 1.07 (95% CI 1-1.15) for every 1,000 COVID-19-related hospital admissions. We recommend maintaining all CRB prevention efforts regardless of the coexistence of other challenges, such as the COVID-19 pandemic.

Trends in the epidemiology of catheter-related bloodstream infections; towards a paradigm shift, Spain, 2007 to 2019.

BackgroundCatheter-related bloodstream infections (CRBSI) are frequent healthcare-associated infections and an important cause of death.AimTo analyse changes in CRBSI epidemiology observed by the Infection Control Catalan Programme (VINCat).MethodsA cohort study including all hospital-acquired CRBSI episodes diagnosed at 55 hospitals (2007-2019) in Catalonia, Spain, was prospectively conducted. CRBSI incidence rates were adjusted per 1,000 patient days. To assess the CRBSI rate trend per year, negative binomial models were used, with the number of events as the dependent variable, and the year as the main independent variable. From each model, the annual rate of CRBSI diagnosed per 1,000 patient days and the incidence rate ratio (IRR) with its 95% confidence intervals (CI) were reported.ResultsDuring the study, 9,290 CRBSI episodes were diagnosed (mean annual incidence rate: 0.20 episodes/1,000 patient days). Patients' median age was 64.1 years; 36.6% (3,403/9,290) were female. In total, 73.7% (n = 6,845) of CRBSI occurred in non-intensive care unit (ICU) wards, 62.7% (n = 5,822) were related to central venous catheter (CVC), 24.1% (n = 2,236) to peripheral venous catheters (PVC) and 13.3% (n = 1,232) to peripherally-inserted central venous catheters (PICVC). Incidence rate fell over the study period (IRR: 0.94; 95%CI: 0.93-0.96), especially in the ICU (IRR: 0.88; 95%CI: 0.87-0.89). As a whole, while episodes of CVC CRBSI fell significantly (IRR: 0.88; 95%CI: 0.87-0.91), peripherally-inserted catheter CRBSI (PVC and PICVC) rose, especially in medical wards (IRR PICVC: 1.08; 95%CI: 1.05-1.11; IRR PVC: 1.03; 95% 1.00-1.05).ConclusionsOver the study, CRBSIs associated with CVC and diagnosed in ICUs decreased while episodes in conventional wards involving peripherally-inserted catheters increased. Hospitals should implement preventive measures in conventional wards.

Daptomycin Plus Fosfomycin Versus Daptomycin Alone for Methicillin-resistant Staphylococcus aureus Bacteremia and Endocarditis: A Randomized Clinical Trial.

BACKGROUND: We aimed to determine whether daptomycin plus fosfomycin provides higher treatment success than daptomycin alone for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and endocarditis. METHODS: A randomized (1:1) phase 3 superiority, open-label, and parallel group clinical trial of adult inpatients with MRSA bacteremia was conducted at 18 Spanish hospitals. Patients were randomly assigned to receive either 10 mg/kg of daptomycin intravenously daily plus 2 g of fosfomycin intravenously every 6 hours, or 10 mg/kg of daptomycin intravenously daily. Primary endpoint was treatment success 6 weeks after the end of therapy. RESULTS: Of 167 patients randomized, 155 completed the trial and were assessed for the primary endpoint. Treatment success at 6 weeks after the end of therapy was achieved in 40 of 74 patients who received daptomycin plus fosfomycin and in 34 of 81 patients who were given daptomycin alone (54.1% vs 42.0%; relative risk, 1.29 [95% confidence interval, .93-1.8]; P = .135). At 6 weeks, daptomycin plus fosfomycin was associated with lower microbiologic failure (0 vs 9 patients; P = .003) and lower complicated bacteremia (16.2% vs 32.1%; P = .022). Adverse events leading to treatment discontinuation occurred in 13 of 74 patients (17.6%) receiving daptomycin plus fosfomycin, and in 4 of 81 patients (4.9%) receiving daptomycin alone (P = .018). CONCLUSIONS: Daptomycin plus fosfomycin provided 12% higher rate of treatment success than daptomycin alone, but this difference did not reach statistical significance. This antibiotic combination prevented microbiological failure and complicated bacteremia, but it was more often associated with adverse events. CLINICAL TRIALS REGISTRATION: NCT01898338.

Effectiveness of vancomycin plus cloxacillin compared with vancomycin, cloxacillin and daptomycin single therapies in the treatment of methicillin-resistant and methicillin-susceptible Staphylococcus aureus in a rabbit model of experimental endocarditis.

OBJECTIVES: To investigate if the addition of cloxacillin to vancomycin enhances the activity of both monotherapies for treating MSSA and MRSA experimental endocarditis (EE) in rabbits. METHODS: Vancomycin plus cloxacillin was compared with the respective monotherapies and daptomycin. In vitro time-kill studies were performed using standard (105 cfu) and high (108 cfu) inocula of five MRSA, one glycopeptide-intermediate (GISA) and five MSSA strains. One MSSA (MSSA-678) and one MRSA (MRSA-277) strain were selected to be used in the in vivo model. A human-like pharmacokinetics model was applied and the equivalents of cloxacillin 2 g/4 h IV and daptomycin 6 mg/kg/day IV were administered. To optimize vancomycin activity, dosage was adjusted to achieve an AUC/MIC ≥400. RESULTS: Daptomycin sterilized significantly more vegetations than cloxacillin (13/13, 100% versus 9/15, 60%; P = 0.02) and showed a trend of better activity than vancomycin (10/14, 71%; P = 0.09) and vancomycin plus cloxacillin (10/14, 71%; P = 0.09) against MSSA-678. Addition of cloxacillin to vancomycin (13/15, 87%) was significantly more effective than vancomycin (8/16, 50%; P = 0.05) and showed similar activity to daptomycin (13/18, 72%; P = 0.6) against MRSA-277. In all treatment arms, the bacterial isolates recovered from vegetations were re-tested and showed the same daptomycin susceptibility as the original strains. CONCLUSIONS: Vancomycin plus cloxacillin proved synergistic and bactericidal activity against MRSA. Daptomycin was the most efficacious option against MSSA and similar to vancomycin plus cloxacillin against MRSA. In settings with high MRSA prevalence, vancomycin plus cloxacillin might be a good alternative for empirical therapy of S. aureus IE.

Cloxacillin or fosfomycin plus daptomycin combinations are more active than cloxacillin monotherapy or combined with gentamicin against MSSA in a rabbit model of experimental endocarditis.

BACKGROUND: In vitro and in vivo activity of daptomycin alone or plus either cloxacillin or fosfomycin compared with cloxacillin alone and cloxacillin plus gentamicin were evaluated in a rabbit model of MSSA experimental endocarditis (EE). METHODS: Five MSSA strains were used in the in vitro time-kill studies at standard (105-106 cfu/mL) and high (108 cfu/mL) inocula. In the in vivo EE model, the following antibiotic combinations were evaluated: cloxacillin (2 g/4 h) alone or combined with gentamicin (1 mg/kg/8 h) or daptomycin (6 mg/kg once daily); and daptomycin (6 mg/kg/day) alone or combined with fosfomycin (2 g/6 h). RESULTS: At standard and high inocula, daptomycin plus fosfomycin or cloxacillin were bactericidal against 4/5 and 5/5 strains, respectively, while cloxacillin plus gentamicin was bactericidal against 3/5 strains at standard inocula but against none at high inocula. Fosfomycin, cloxacillin, gentamicin and daptomycin MIC/MBCs of the MSSA-678 strain used in the EE model were: 8/64, 0.25/0.5, 0.25/0.5 and 1/8 mg/L, respectively. Adding gentamicin to cloxacillin significantly reduced bacterial density in vegetations compared with cloxacillin monotherapy (P = 0.026). Adding fosfomycin or cloxacillin to daptomycin [10/11 (93%) and 8/11 (73%), respectively] significantly improved the efficacy of daptomycin in sterilizing vegetations [0/11 (0%), P < 0.001 for both combinations] and showed better activity than cloxacillin alone [0/10 (0%), P < 0.001 for both combinations] and cloxacillin plus gentamicin [3/10 (30%), P = 0.086 for cloxacillin plus daptomycin and P = 0.008 for fosfomycin plus daptomycin]. No recovered isolates showed increased daptomycin MIC. CONCLUSIONS: The addition of cloxacillin or fosfomycin to daptomycin is synergistic and rapidly bactericidal, showing better activity than cloxacillin plus gentamicin for treating MSSA EE, supporting their clinical use.

QuantiFERON-TB Gold In-Tube as a Confirmatory Test for Tuberculin Skin Test in Tuberculosis Contact Tracing: A Noninferiority Clinical Trial.

Background: Screening strategies based on interferon-γ release assays in tuberculosis contact tracing may reduce the need for preventive therapy without increasing subsequent active disease. Methods: We conducted an open-label, randomized trial to test the noninferiority of a 2-step strategy with the tuberculin skin test (TST) followed by QuantiFERON-TB Gold In-Tube (QFT-GIT) as a confirmatory test (the TST/QFT arm) to the standard TST-alone strategy (TST arm) for targeting preventive therapy in household contacts of patients with tuberculosis. Participants were followed for 24 months after randomization. The primary endpoint was the development of tuberculosis, with a noninferiority margin of 1.5 percentage points. Results: A total of 871 contacts were randomized. Four contacts in the TST arm and 2 in the TST/QFT arm developed tuberculosis. In the modified intention-to-treat analysis, this accounted for 0.99% in the TST arm and 0.51% in the TST/QFT arm (-0.48% difference; 97.5% confidence interval [CI], -1.86% to 0.90%); in the per-protocol analysis, the corresponding rates were 1.67% and 0.82% in the TST and TST/QFT arms, respectively (-0.85% difference; 97.5% CI, -3.14% to 1.43%). Of the 792 contacts analyzed, 65.3% in the TST arm and 42.2% in the TST/QFT arm were diagnosed with tuberculosis infection (23.1% difference; 95% CI, 16.4% to 30.0%). Conclusions: In low-incidence settings, screening household contacts with the TST and using QFT-GIT as a confirmatory test is not inferior to TST-alone for preventing active tuberculosis, allowing a safe reduction of preventive treatments. Clinical Trials Registration: NCT01223534.

The Combination of Daptomycin and Fosfomycin Has Synergistic, Potent, and Rapid Bactericidal Activity against Methicillin-Resistant Staphylococcus aureus in a Rabbit Model of Experimental Endocarditis.

We investigated whether the addition of fosfomycin or cloxacillin to daptomycin provides better outcomes in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) experimental aortic endocarditis in rabbits. Five MRSA strains were used to perform in vitro time-kill studies using standard (106) and high (108) inocula. Combined therapy was compared to daptomycin monotherapy treatment in the MRSA experimental endocarditis model. A human-like pharmacokinetics model was applied, and the equivalents of cloxacillin at 2 g/4 h, fosfomycin at 2 g/6 h, and daptomycin at 6 to 10 mg/kg/day were administered intravenously. A combination of daptomycin and either fosfomycin or cloxacillin was synergistic in the five strains tested at both inocula. A bactericidal effect was detected in four of five strains tested with both combinations. The MRSA-277 strain (vancomycin MIC, 2 µg/ml) was used for the experimental endocarditis model. Daptomycin plus fosfomycin significantly improved the efficacy of daptomycin monotherapy at 6 mg/kg/day in terms of both the proportion of sterile vegetations (100% versus 72%, P = 0.046) and the decrease in the density of bacteria within the vegetations (P = 0.025). Daptomycin plus fosfomycin was as effective as daptomycin monotherapy at 10 mg/kg/day (100% versus 93%, P = 1.00) and had activity similar to that of daptomycin plus cloxacillin when daptomycin was administered at 6 mg/kg/day (100% versus 88%, P = 0.48). Daptomycin nonsusceptibility was not detected in any of the isolates recovered from vegetations. In conclusion, for the treatment of MRSA experimental endocarditis, the combination of daptomycin plus fosfomycin showed synergistic and bactericidal activity.

Empiric Therapy With Carbapenem-Sparing Regimens for Bloodstream Infections due to Extended-Spectrum ß-Lactamase-Producing Enterobacteriaceae: Results From the INCREMENT Cohort.

BACKGROUND: There is little information about the efficacy of active alternative drugs to carbapenems except ß-lactam/ß-lactamase inhibitors for the treatment of bloodstream infections (BSIs) due to extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E). The objective of this study was to assess the outcomes of patients with BSI due to ESBL-E who received empiric therapy with such drugs (other active drugs [OADs]) or carbapenems. METHODS: A multinational retrospective cohort study of patients with BSI due to ESBL-E who received empiric treatment with OADs or carbapenems was performed. Cox regression including a propensity score for receiving OADs was performed to analyze 30-day all-cause mortality as main outcome. Clinical failure and length of stay were also analyzed. RESULTS: Overall, 335 patients were included; 249 received empiric carbapenems and 86 OADs. The most frequent OADs were aminoglycosides (43 patients) and fluoroquinolones (20 patients). Empiric therapy with OADs was not associated with mortality (hazard ratio [HR], 0.75; 95% confidence interval [CI], .38-1.48) in the Cox regression analysis. Propensity score-matched pairs, subgroups, and sensitivity analyses did not show different trends; specifically, the adjusted HR for aminoglycosides was 1.05 (95% CI, .51-2.16). OADs were neither associated with 14-day clinical failure (adjusted odds ratio, 0.62; 95% CI, .29-1.36) nor length of hospital stay. CONCLUSIONS: We were unable to show that empiric treatment with OAD was associated with a worse outcome compared with carbapenems. This information allows more options to be considered for empiric therapy, at least for some patients, depending on local susceptibility patterns of ESBL-E.

AUC/MIC Pharmacodynamic Target Is Not a Good Predictor of Vancomycin Efficacy in Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis.

The aim of this in vivo study was to compare the efficacy of vancomycin at standard doses (VAN-SD) to that of VAN at adjusted doses (VAN-AD) in achieving a VAN area under the curve/MIC ratio (AUC/MIC) of ≥400 against three methicillin-resistant Staphylococcus aureus (MRSA) strains with different microdilution VAN MICs in an experimental endocarditis model. The valve vegetation bacterial counts after 48 h of VAN therapy were compared, and no differences were observed between the two treatment groups for any of the three strains tested. Overall, for VAN-SD and VAN-AD, the rates of sterile vegetations were 15/45 (33.3%) and 21/49 (42.8%) (P = 0.343), while the medians (interquartile ranges [IQRs]) for log10 CFU/g of vegetation were 2 (0 to 6.9) and 2 (0 to 4.5) (P = 0.384), respectively. In conclusion, this VAN AUC/MIC pharmacodynamic target was not a good predictor of vancomycin efficacy in MRSA experimental endocarditis.

High vancomycin MICs predict the development of infective endocarditis in patients with catheter-related bacteraemia due to methicillin-resistant Staphylococcus aureus.

Background: It has been suggested that there is an increased risk of treatment failure in episodes of MRSA bloodstream infection (BSI) caused by strains with high vancomycin MICs. However, it is unknown if this phenomenon may also act as a risk factor for the development of infective endocarditis (IE). Methods: We analysed 207 episodes of catheter-related (CR)-BSI recruited from June 2008 to December 2009 within a prospective study on MRSA BSI in 21 Spanish hospitals. Vancomycin susceptibility was centrally tested. The impact of high vancomycin MIC values (≥1.5 mg/L by Etest) on the subsequent development of IE was investigated by Cox regression. Results: High vancomycin MIC values were observed in 46.9% of the isolates. Initial therapy consisted of vancomycin [99 episodes (44.7%)], daptomycin [25 (12.1%)], linezolid [18 (8.7%)] and other antistaphylococcal agents [16 (7.7%)]. Haematogenous complications occurred in 41 patients (19.8%), including 10 episodes complicated by IE. Early (48 h) and late (30 day) all-cause mortality were 3.4% and 25.1%, respectively. High vancomycin MIC isolates were more common among patients that developed IE compared with those free from this complication [90.9% (9/10) versus 44.7% (88/197); P = 0.007]. This association remained significant after adjusting for multiple confounders (including initial antibiotic therapy and catheter removal) in different models (minimum hazard ratio: 9.18; 95% CI: 1.16-72.78; P = 0.036). There were no differences in mortality according to vancomycin MIC values. Conclusions: Decreased susceptibility to vancomycin acted as a predictor of the development of IE complicating MRSA CR-BSI.

Development and validation of the INCREMENT-ESBL predictive score for mortality in patients with bloodstream infections due to extended-spectrum-ß-lactamase-producing Enterobacteriaceae.

Background: Bloodstream infections (BSIs) due to ESBL-producing Enterobacteriaceae (ESBL-E) are frequent yet outcome prediction rules for clinical use have not been developed. The objective was to define and validate a predictive risk score for 30 day mortality. Methods: A multinational retrospective cohort study including consecutive episodes of BSI due to ESBL-E was performed; cases were randomly assigned to a derivation cohort (DC) or a validation cohort (VC). The main outcome variable was all-cause 30 day mortality. A predictive score was developed using logistic regression coefficients for the DC, then tested in the VC. Results: The DC and VC included 622 and 328 episodes, respectively. The final multivariate logistic regression model for mortality in the DC included age >50 years (OR = 2.63; 95% CI: 1.18-5.85; 3 points), infection due to Klebsiella spp. (OR = 2.08; 95% CI: 1.21-3.58; 2 points), source other than urinary tract (OR = 3.6; 95% CI: 2.02-6.44; 3 points), fatal underlying disease (OR = 3.91; 95% CI: 2.24-6.80; 4 points), Pitt score >3 (OR = 3.04; 95 CI: 1.69-5.47; 3 points), severe sepsis or septic shock at presentation (OR = 4.8; 95% CI: 2.72-8.46; 4 points) and inappropriate early targeted therapy (OR = 2.47; 95% CI: 1.58-4.63; 2 points). The score showed an area under the receiver operating curve (AUROC) of 0.85 in the DC and 0.82 in the VC. Mortality rates for patients with scores of < 11 and ≥11 were 5.6% and 45.9%, respectively, in the DC, and 5.4% and 34.8% in the VC. Conclusions: We developed and validated an easy-to-collect predictive scoring model for all-cause 30 day mortality useful for identifying patients at high and low risk of mortality.

A Multinational, Preregistered Cohort Study of ß-Lactam/ß-Lactamase Inhibitor Combinations for Treatment of Bloodstream Infections Due to Extended-Spectrum-ß-Lactamase-Producing Enterobacteriaceae.

The spread of extended-spectrum-ß-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) is leading to increased carbapenem consumption. Alternatives to carbapenems need to be investigated. We investigated whether ß-lactam/ß-lactamase inhibitor (BLBLI) combinations are as effective as carbapenems in the treatment of bloodstream infections (BSI) due to ESBL-E. A multinational, retrospective cohort study was performed. Patients with monomicrobial BSI due to ESBL-E were studied; specific criteria were applied for inclusion of patients in the empirical-therapy (ET) cohort (ETC; 365 patients), targeted-therapy (TT) cohort (TTC; 601 patients), and global cohort (GC; 627 patients). The main outcome variables were cure/improvement rate at day 14 and all-cause 30-day mortality. Multivariate analysis, propensity scores (PS), and sensitivity analyses were used to control for confounding. The cure/improvement rates with BLBLIs and carbapenems were 80.0% and 78.9% in the ETC and 90.2% and 85.5% in the TTC, respectively. The 30-day mortality rates were 17.6% and 20% in the ETC and 9.8% and 13.9% in the TTC, respectively. The adjusted odds ratio (OR) (95% confidence interval [CI]) values for cure/improvement rate with ET with BLBLIs were 1.37 (0.69 to 2.76); for TT, they were 1.61 (0.58 to 4.86). Regarding 30-day mortality, the adjusted OR (95% CI) values were 0.55 (0.25 to 1.18) for ET and 0.59 (0.19 to 1.71) for TT. The results were consistent in all subgroups studied, in a stratified analysis according to quartiles of PS, in PS-matched cases, and in the GC. BLBLIs, if active in vitro, appear to be as effective as carbapenems for ET and TT of BSI due to ESLB-E regardless of the source and specific species. These data may help to avoid the overuse of carbapenems. (This study has been registered at ClinicalTrials.gov under registration no. NCT01764490.).

Ertapenem for the treatment of bloodstream infections due to ESBL-producing Enterobacteriaceae: a multinational pre-registered cohort study.

OBJECTIVES: Data about the efficacy of ertapenem for the treatment of bloodstream infections (BSI) due to ESBL-producing Enterobacteriaceae (ESBL-E) are limited. We compared the clinical efficacy of ertapenem and other carbapenems in monomicrobial BSI due to ESBL-E. METHODS: A multinational retrospective cohort study (INCREMENT project) was performed (ClinicalTrials.gov identifier: NCT01764490). Patients given monotherapy with ertapenem or other carbapenems were compared. Empirical and targeted therapies were analysed. Propensity scores were used to control for confounding; sensitivity analyses were performed in subgroups. The outcome variables were cure/improvement rate at day 14 and all-cause 30 day mortality. RESULTS: The empirical therapy cohort (ETC) and the targeted therapy cohort (TTC) included 195 and 509 patients, respectively. Cure/improvement rates were 90.6% with ertapenem and 75.5% with other carbapenems (P = 0.06) in the ETC and 89.8% and 82.6% (P = 0.02) in the TTC, respectively; 30 day mortality rates were 3.1% and 23.3% (P = 0.01) in the ETC and 9.3% and 17.1% (P = 0.01) in the TTC, respectively. Adjusted ORs (95% CI) for cure/improvement with empirical and targeted ertapenem were 1.87 (0.24-20.08; P = 0.58) and 1.04 (0.44-2.50; P = 0.92), respectively. For the propensity-matched cohorts it was 1.18 (0.43-3.29; P = 0.74). Regarding 30 day mortality, the adjusted HR (95% CI) for targeted ertapenem was 0.93 (0.43-2.03; P = 0.86) and for the propensity-matched cohorts it was 1.05 (0.46-2.44; P = 0.90). Sensitivity analyses were consistent except for patients with severe sepsis/septic shock, which showed a non-significant trend favouring other carbapenems. CONCLUSIONS: Ertapenem appears as effective as other carbapenems for empirical and targeted therapy of BSI due to ESBL-E, but further studies are needed for patients with severe sepsis/septic shock.

Prevalence of methicillin-resistant Staphylococcus aureus colonization in HIV-infected patients in Barcelona, Spain: a cross-sectional study.

BACKGROUND: Colonization by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been found to be markedly more common in HIV-infected individuals in the USA. Studies evaluating the prevalence MRSA colonization in HIV-infected populations in Europe are scarce. The aim of this study was to investigate the prevalence of MRSA colonization in a cohort of HIV-infected patients in Barcelona, Spain. METHODS: Nasal and pharyngeal S. aureus carriage was assessed in a random sample of 190 patients from an outpatient HIV clinic. Nasal and pharyngeal swab specimens were obtained for staphylococcal culture from 190 and 110 patients respectively. All MRSA isolates were screened for Panton-Valentine leukocidin (PVL) genes by PCR. Molecular characterization of MRSA isolates was performed by multilocus sequence typing. Data related to HIV infection, healthcare exposure, and previously described risk factors for MRSA were collected from medical records and a questionnaire administered to each patient. RESULTS: The patients' characteristics were as follows: male, 83 %; median (IQR) age, 45 (39-49) years; intravenous drug users, 39 %; men who have sex with men, 32 %; heterosexual, 26 %; CD4 count, 528/µL (IQR 351-740); on antiretroviral therapy, 96 %; and undetectable plasma viral load, 80 %. Sixty-five patients (34 %) were colonized by S. aureus. MRSA colonization was found in 1 % and 2 % of nasal and pharyngeal samples respectively. No PVL positive MRSA strains were detected and all the MRSA isolates belonged to typical hospital-acquired clones. CONCLUSIONS: Our data suggest that CA-MRSA colonization is not currently a problem in HIV-infected individuals in our area.

Methicillin-resistant Staphylococcus aureus (MRSA) catheter-related bacteraemia in haemodialysis patients.

BACKGROUND: The aim of the study was to determine clinical and microbiological differences between patients with methicillin-resistant Staphylococcus aureus (MRSA) catheter-related bacteraemia (CRB) undergoing or not undergoing haemodialysis, and to compare outcomes. METHODS: Prospective multicentre study conducted at 21 Spanish hospitals of patients with MRSA bacteraemia diagnosed between June 2008 and December 2009. Patients with MRSA-CRB were selected. Data of patients on haemodialysis (HD-CRB) and those not on haemodialysis (non-HD-CRB) were compared. RESULTS: Among 579 episodes of MRSA bacteraemia, 218 (37.7%) were CRB. Thirty-four (15.6%) were HD-CRB and 184 (84.4%) non-HD-CRB. All HD-CRB patients acquired the infection at dialysis centres, while in 85.3% of the non-HD-CRB group the infection was nosocomial (p < .001). There were no differences in age, gender or severity of bacteraemia (Pitt score); comorbidities (Charlson score ≥ 4) were higher in the HD-CRB group than in the non-HD-CRB group (73.5% vs. 46.2%, p = .003). Although there were no differences in VAN-MIC ≥ 1.5 mg/L according to microdilution, using the E-test a higher rate of VAN-MIC ≥ 1.5 mg/L was observed in HD-CRB than in non-HD-CRB patients (63.3% vs. 44.1%, p = .051). Vancomycin was more frequently administered in the HD-CRB group than in the non-HD-CRB group (82.3% vs. 42.4%, p = <.001) and therefore the appropriate empirical therapy was significantly higher in HD-CRB group (91.2% vs. 73.9%, p = .029). There were no differences with regard to catheter removal (79.4% vs. 84.2%, p = .555, respectively). No significant differences in mortality rate were observed between both groups (Overall mortality: 11.8% vs. 27.2%, p = .081, respectively), but there was a trend towards a higher recurrence rate in HD-CRB group (8.8% vs. 2.2%, p = .076). CONCLUSIONS: In our multicentre study, ambulatory patients in chronic haemodialysis represented a significant proportion of cases of MRSA catheter-related bacteraemia. Although haemodialysis patients with MRSA catheter-related bacteraemia had significantly more comorbidities and higher proportion of strains with reduced vancomycin susceptibility than non-haemodialysis patients, overall mortality between both groups was similar.

Diagnosis and treatment of bacteremia and endocarditis due to Staphylococcus aureus. A clinical guideline from the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC).

Both bacteremia and infective endocarditis caused by Staphylococcus aureus are common and severe diseases. The prognosis may darken not infrequently, especially in the presence of intracardiac devices or methicillin-resistance. Indeed, the optimization of the antimicrobial therapy is a key step in the outcome of these infections. The high rates of treatment failure and the increasing interest in the influence of vancomycin susceptibility in the outcome of infections caused by both methicillin-susceptible and -resistant isolates has led to the research of novel therapeutic schemes. Specifically, the interest raised in recent years on the new antimicrobials with activity against methicillin-resistant staphylococci has been also extended to infections caused by susceptible strains, which still carry the most important burden of infection. Recent clinical and experimental research has focused in the activity of new combinations of antimicrobials, their indication and role still being debatable. Also, the impact of an appropriate empirical antimicrobial treatment has acquired relevance in recent years. Finally, it is noteworthy the impact of the implementation of a systematic bundle of measures for improving the outcome. The aim of this clinical guideline is to provide an ensemble of recommendations in order to improve the treatment and prognosis of bacteremia and infective endocarditis caused by S. aureus, in accordance to the latest evidence published.

Executive summary of the diagnosis and treatment of bacteremia and endocarditis due to Staphylococcus aureus. A clinical guideline from the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC).

Bacteremia and infective endocarditis caused by Staphylococcus aureus are common and severe diseases. Optimization of treatment is fundamental in the prognosis of these infections. The high rates of treatment failure and the increasing interest in the influence of vancomycin susceptibility in the outcome of infections caused by both methicillin-susceptible and -resistant isolates have led to research on novel therapeutic schemes. The interest in the new antimicrobials with activity against methicillin-resistant staphylococci has been extended to susceptible strains, which still carry the most important burden of infection. New combinations of antimicrobials have been investigated in experimental and clinical studies, but their role is still being debated. Also, the appropriateness of the initial empirical therapy has acquired relevance in recent years. The aim of this guideline is to update the 2009 guidelines and to provide an ensemble of recommendations in order to improve the treatment of staphylococcal bacteremia and infective endocarditis, in accordance with the latest published evidence.

Efficacy and safety of fosfomycin plus imipenem as rescue therapy for complicated bacteremia and endocarditis due to methicillin-resistant Staphylococcus aureus: a multicenter clinical trial.

BACKGROUND: There is an urgent need for alternative rescue therapies in invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA). We assessed the clinical efficacy and safety of the combination of fosfomycin and imipenem as rescue therapy for MRSA infective endocarditis and complicated bacteremia. METHODS: The trial was conducted between 2001 and 2010 in 3 Spanish hospitals. Adult patients with complicated MRSA bacteremia or endocarditis requiring rescue therapy were eligible for the study. Treatment with fosfomycin (2 g/6 hours IV) plus imipenem (1 g/6 hours IV) was started and monitored. The primary efficacy endpoints were percentage of sterile blood cultures at 72 hours and clinical success rate assessed at the test-of-cure visit (45 days after the end of therapy). RESULTS: The combination was administered in 12 patients with endocarditis, 2 with vascular graft infection, and 2 with complicated bacteremia. Therapy had previously failed with vancomycin in 9 patients, daptomycin in 2, and sequential antibiotics in 5. Blood cultures were negative 72 hours after the first dose of the combination in all cases. The success rate was 69%, and only 1 of 5 deaths was related to the MRSA infection. Although the combination was safe in most patients (94%), a patient with liver cirrhosis died of multiorgan failure secondary to sodium overload. There were no episodes of breakthrough bacteremia or relapse. CONCLUSIONS: Fosfomycin plus imipenem was an effective and safe combination when used as rescue therapy for complicated MRSA bloodstream infections and deserves further clinical evaluation as initial therapy in these infections.

Genomic analysis of Staphylococcus aureus isolates from bacteremia reveals genetic features associated with the COVID-19 pandemic.

Genomic analyses of bacterial isolates are effective to compare the prevalence of antibiotic resistance genes and virulence determinants in different contexts. This study provides a comprehensive genomic description of 339 Staphylococcus aureus strains isolated from patients with bacteremia (2014-2022). Nosocomial acquisition accounted for 56.6% of cases, with vascular catheters being the main infection source (31.8%). Fatality (27.4%), persistent bacteremia (19.5%), and septic emboli (24.2%) were documented. During the COVID-19 pandemic, S. aureus bacteremia episodes increased by 140%. Genetic features in pandemic isolates revealed higher prevalence of methicillin (mecA) and macrolide (msrA and mphC) resistance genes. Additionally, genes encoding clumping factors A and B, involved in fibrinogen binding, were more prevalent. This was linked to extensive macrolide use in COVID-19 accessory therapy and elevated fibrinogen levels in SARS-CoV-2 infection. These findings highlight S. aureus adaptation to COVID-19 selective pressures and the value of whole-genome sequencing in molecular epidemiology studies.

Prevalence and Risk Factors for Colonization by Multidrug-Resistant Microorganisms among Long-Term Travelers and Recently Arrived Migrants.

Multidrug-resistant (MDR) bacteria have become one of the most important health problems. We aimed to assess whether international travel may facilitate their spread through the colonization of asymptomatic travelers. A cross-sectional study was conducted (November 2018 to February 2022). Pharyngeal and rectal swabs were obtained from long-term travelers and recently arrived migrants from non-European countries, and an epidemiological survey was performed. Colonization by Gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA) was determined by chromogenic media and MALDI-TOF-MS. Resistance mechanisms were determined by the biochip-based molecular biology technique. Risk factors for colonization were assessed by logistic regression. In total, 122 participants were included: 59 (48.4%) recently arrived migrants and 63 (51.6%) long-term travelers. After their trip, 14 (11.5%) participants-5 (8.5%) migrants and 9 (14.3%) travelers-had rectal colonization by one MDR bacterium. Escherichia coli carrying the extended-spectrum beta-lactamase (ESBL) CTX-M-15 was the most frequent. No participants were colonized by MRSA or carbapenemase-producing Enterobacteriaceae. The only risk factor independently associated with MDR bacterial colonization was previous hospital attention [OR, 95% CI: 10.16 (2.06-50.06)]. The risk of colonization by MDR bacteria among recently arrived migrants and long-term travelers is similar in both groups and independently associated with previous hospital attention.