Impact of an interventional bundle on complications associated with peripheral venous catheters in elderly patients.

PURPOSE: Elderly patients admitted to geriatrics departments often require peripheral venous catheters (PVC), which should be inserted and maintained following a series of preventive recommendations. Our objective was to evaluate the impact of a training bundle comprising measures aimed at reducing complications associated with the use of PVC in elderly patients admitted to a tertiary teaching hospital. METHODS: We performed a prospective study of patients who received a PVC within 24 h of admission to a geriatrics department. After a 10-month pre-interventional period, we implemented an educational and interventional bundle over a 9-month period. Follow-up was until catheter withdrawal. We analyzed and compared clinical and microbiological data between both study periods. RESULTS: A total of 344 patients (475 PVC) were included (pre-intervention period, 204 patients (285 PVC); post-intervention period, 140 patients (190 PVC)). No statistically significant differences in demographic characteristics were observed between the study periods. The colonization and phlebitis rates per 1000 admissions in both periods were, respectively, 36.7 vs. 24.3 (p = 0.198) and 81.5 vs. 65.1 (p = 0.457). The main reason for catheter withdrawal was obstruction/malfunctioning (33.3%). Obstruction rate was higher for those inserted in the hand than for those inserted at other sites (55.7% vs. 44.3%, p = 0.045). CONCLUSIONS: We found no statistically significant differences regarding phlebitis and catheter tip colonization rates. It is necessary to carry out randomized studies assessing the most cost-effective measure to reduce complications associated with PVC.

Infectious complications following major heart surgery from the day of the surgery to hospital discharge.

BACKGROUND: At some point in their lives, many people will require major heart surgery (MHS). Patients are generally older adults with various risk factors for infection. However, the incidence of infection after MHS is poorly known, as reported infection data are frequently biased due to different factors like the surgical procedure, postoperative timing, and infectious syndromes or etiologic agents, among others. In addition, most patient data are retrospectively obtained. PURPOSE AND METHODS: Data were prospectively collected regarding the incidence of all nosocomial infections produced from the time of surgery to hospital discharge in a cohort of 800 adults consecutively undergoing a MHS procedure. RESULTS: During postoperative hospitalization, 124 of the 800 participants developed one or more infections (15.5%): during their ICU stay in 68 patients (54.8%), during their stay on the general ward post ICU in 50 (40.3%), and during their stay in both wards in 6 (4.8%). The most common infections were pneumonia (related or not to mechanical ventilation), surgical site and bloodstream. As etiological agents, 193 pathogens were isolated: mostly Gram-negative bacilli (54.4%), followed by Gram-positive bacteria (30%), viruses (4.6%) and fungi (1.5%). In our cohort, all-cause mortality was recorded in 33 participants (4.1%) and 9 infection-related deaths (1.1%) were produced. Among subjects who developed infections, overall mortality was 13.7% and in those who did not, this was only 2.3%. CONCLUSION: Infection following MHS remains frequent and severe. Our data suggest that hospital-acquired infection studies should consider episodes of infection in all populations during their entire hospital stay and not only those related to specific clinical syndromes or acquired while the patient is in intensive care.

Endotracheal tubes coated with a broad-spectrum antibacterial ceragenin reduce bacterial biofilm in an in vitro bench top model.

BACKGROUND: Ventilator-associated pneumonia is one of the most common nosocomial infections, caused mainly by bacterial/fungal biofilm. Therefore, it is necessary to develop preventive strategies to avoid biofilm formation based on new compounds. OBJECTIVES: We performed an in vitro study to compare the efficacy of endotracheal tubes (ETTs) coated with the ceragenin CSA-131 and that of uncoated ETTs against the biofilm of clinical strains of Pseudomonas aeruginosa (PA), Escherichia coli (EC) and Staphylococcus aureus (SA). METHODS: We applied an in vitro bench top model using coated and uncoated ETTs that were treated with three different clinical strains of PA, EC and SA for 5 days. After exposure to biofilm, ETTs were analysed for cfu count by culture of sonicate and total number of cells by confocal laser scanning microscopy. RESULTS: The median (IQR) cfu/mL counts of PA, EC and SA in coated and uncoated ETTs were, respectively, as follows: 1.00 × 101 (0.0-3.3 × 102) versus 3.32 × 109 (6.6 × 108-3.8 × 109), P < 0.001; 0.0 (0.0-5.4 × 103) versus 1.32 × 106 (2.3 × 103-5.0 × 107), P < 0.001; and 8.1 × 105 (8.5 × 101-1.4 × 109) versus 2.7 × 108 (8.6 × 106-1.6 × 1011), P = 0.058. The median (IQR) total number of cells of PA, EC and SA in coated and non-coated ETTs were, respectively, as follows: 11.0 [5.5-not applicable (NA)] versus 87.9 (60.5-NA), P = 0.05; 9.1 (6.7-NA) versus 62.6 (42.0-NA), P = 0.05; and 97.7 (94.6-NA) versus 187.3 (43.9-NA), P = 0.827. CONCLUSIONS: We demonstrated significantly reduced biofilm formation in coated ETTs. However, the difference for SA was not statistically significant. Future clinical studies are needed to support our findings.

In Vitro Study To Evaluate the Bioactivity of Freezing a Heparin-Based Dalbavancin Lock Solution.

The use of dalbavancin as a catheter lock solution must be addressed in depth before implementation in clinical practice. We assessed whether a heparin-based dalbavancin lock solution could be frozen in single-dose vials for 6 months without affecting its bioactivity against biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). Over 6 months, we tested the bioactivity of a frozen solution of dalbavancin (≈1 mg/ml) plus heparin (60 IU) in terms of CFU counts and metabolic activity against biofilms of Staphylococcus aureus ATCC 43300 (MRSA) and Staphylococcus epidermidis ATCC 35984 (MRSE). The Anti-Xa assay was also performed to assess whether the anticoagulant activity of heparin was reduced under freezing. Every month, we compared the mean value of each variable with that obtained at baseline (before freezing, month 0) using both clinical criteria (values were within 25% of the baseline value) and statistical criteria (linear mixed models). At the end of the experiment (month 6), neither a clinically nor a statistically significant reduction in the bioactivity of dalbavancin-heparin solution was observed in terms of CFU counts and metabolic activity against biofilm of MRSA. Regarding MRSE, considering the clinical criteria, neither CFU counts nor metabolic activity decreased significantly. However, the reduction was statistically significant for all variables. Anti-Xa values (mean [standard deviation] international units per milliliter) for heparin in combination with dalbavancin were within 25% of the heparin-water value. A heparin-based dalbavancin lock solution can be frozen for up to 6 months with no effect on its bioactivity against MRSA and MRSE biofilms.

Selective digestive decontamination solution used as "lock therapy" prevents and eradicates bacterial biofilm in an in vitro bench-top model.

BACKGROUND: Most preventing measures for reducing ventilator-associated pneumonia (VAP) are based mainly on the decolonization of the internal surface of the endotracheal tubes (ETTs). However, it has been demonstrated that bacterial biofilm can also be formed on the external surface of ETTs. Our objective was to test in vitro the efficacy of selective digestive decontamination solution (SDDs) onto ETT to prevent biofilm formation and eradicate preformed biofilms of three different microorganisms of VAP. METHODS: We used an in vitro model in which we applied, at the subglottic space of ETT, biofilms of either P. aeruginosa ATCC 15442, or E. coli ATCC 25922, or S. aureus ATCC 29213, and the SDDs at the same time (prophylaxis) or after 72 h of biofilm forming (treatment). ETT were incubated during 5 days with a regimen of 2 h-locks. ETT fragments were analyzed by sonication and confocal laser scanning microscopy to calculate the percentage reduction of cfu and viable cells, respectively. RESULTS: Median (IQR) percentage reduction of live cells and cfu/ml counts after treatment were, respectively, 53.2% (39.4%-64.1%) and 100% (100%-100.0%) for P. aeruginosa, and 67.9% (46.7%-78.7%) and 100% (100%-100.0%) for E. coli. S. aureus presented a complete eradication by both methods. After prophylaxis, there were absence of live cells and cfu/ml counts for all microorganisms. CONCLUSIONS: SDDs used as "lock therapy" in the subglottic space is a promising prophylactic approach that could be used in combination with the oro-digestive decontamination procedure in the prevention of VAP.

T2Candida MR as a predictor of outcome in patients with suspected invasive candidiasis starting empirical antifungal treatment: a prospective pilot study.

Objectives: We assessed the potential role of T2Candida MR (T2MR) and serological biomarkers [ß-d-glucan (BDG) or Candida albicans germ tube antibodies (CAGTA)], alone or in combination with standard cultures, for identifying patients with suspected invasive candidiasis (IC), who may benefit from maintaining antifungal therapy. Methods: Prospective observational multicentre study including all adult patients receiving empirical antifungal therapy for suspected IC, from January to June 2017. CAGTA, BDG and T2MR were determined at baseline and at +2 and +4 days after enrolment. Primary endpoint was the diagnostic value of CAGTA, BDG and T2MR, alone or in combination with standard culture, to predict diagnosis of IC and/or mortality in the first 7 days after starting antifungal therapy (poor outcome). Results: Overall, 14/49 patients (28.6%) had a poor outcome (7 died within the first 7 days of antifungal therapy, whereas 7 ended with a diagnosis of IC). CAGTA [3/14 (21.4%) versus 8/35 (22.9%), P = 1] and BDG [8/14 (57.1%) versus 17/35 (48.6%), P = 0.75] results were similar in poor- and good-outcome patients. Conversely, a positive T2MR was associated with a higher risk of poor outcome [5/14 (35.7%) versus 0/35 (0.0%) P = 0.0001]. Specificity and positive predictive value of a positive T2MR for predicting poor outcome were both 100%, with a negative predictive value of 79.6%. After testing the combinations of biomarkers/standard cultures and T2MR/standard cultures, the combination of T2MR/standard cultures showed a high capacity to discriminate patients with poor outcome from those with good clinical evolution. Conclusions: T2MR may be of significant utility to identify patients who may benefit from maintaining antifungal therapy.

T2MR contributes to the very early diagnosis of complicated candidaemia. A prospective study.

Objectives: Diagnosis of complicated candidaemia represents a challenge for clinicians since early clinical manifestations may be non-specific and difficult to identify, thus precluding an appropriate treatment. Patients and methods: This was a multicentre prospective study for predicting complicated episodes in patients with bloodstream infection caused by Candida species, while assessing the value of follow-up blood cultures (BCs) and the persistence of positive results for T2Candida MR (T2MR) and blood ß-d-glucan (BDG) tests. Immediately after the first positive BC yielding Candida species, samples were obtained on days 0, +2, +4, +7 and +14, to simultaneously perform follow-up BC, T2MR and BDG. An episode of candidaemia was defined as 'complicated' when (i) it caused septic metastasis; and/or (ii) it was the cause of the patient's death. Results: From January to June 2017, 30 patients were enrolled in the study. Of these, nine (30%) had complicated candidaemia. Values of persistently positive samples for the prediction of complicated episodes for BCs, T2MR and BDG, respectively, were as follows: sensitivity (44.4%, 100%, 100%); specificity (76.1%, 76.1%, 38.9%); positive predictive value (PPV) (44.4%, 64.2%, 40.9%) and negative predictive value (NPV) (76.1%, 100%, 100%). In multivariate analysis, having a positive T2MR within the first 5 days was associated with an almost 37-fold higher risk of developing complicated candidaemia. Conclusions: The T2MR test performed in patients with proven candidaemia may be a better marker of complicated infection than follow-up BCs or BDG. It is possible that this test may change current clinical practice, influencing the length and type of antifungal therapy in this population.

Impact of a training program on adherence to recommendations for care of venous lines in internal medicine departments in Spain.

A high percentage of venous lines (VLs) are placed in non-ICU patients, particularly those treated in the internal medicine department (IMD). We assessed adherence to VL care after a training program aimed at nurses and clinicians attending patients admitted to Spanish IMDs. We performed a multicenter prospective observational point prevalence study in 14 Spanish IMDs in 2013 and 2016. We included all adult patients (> 18 years) admitted to IMDs on the study day and reviewed nursing records for patients with VL in place before and after a 1-year training program during 2015. Answers from an interview with head nurses of the IMDs regarding commonly used practices in the daily management of VLs were also compared. A total of 638 and 693 patients were seen during each period, respectively, and 530 and 598 patients had ≥ 1 VL implanted (83.1 vs. 86.3%). Catheters were considered unnecessary in 12.8 and 15.0% of cases (p = 0.28). Daily recording of the need for catheter use increased from 43.8 to 71.8% (p < 0.001). Furthermore, daily monitoring of the insertion site remained very frequent (94.4 vs. 92.2%; p = 0.16). The date of insertion was recorded in 86.3 and 85.5% of cases (p = 0.73), and no combination of closed connectors with open caps increased from 74.8 to 90.3% (p < 0.001). Overall, head nurses' knowledge improved in 4 out of 14 recommendations assessed (28.6%). A simple and easy program for training on management of VLs in Spanish IMDs was associated with improved quality of care.

Eradication of P. aeruginosa biofilm in endotracheal tubes based on lock therapy: results from an in vitro study.

BACKGROUND: Despite the several strategies available for the management of biofilm-associated ventilator-associated pneumonia, data regarding the efficacy of applying antibiotics to the subglottic space (SS) are scarce. We created an in vitro model to assess the efficacy of antibiotic lock therapy (ALT) applied in the SS for eradication of Pseudomonas aeruginosa biofilm in endotracheal tubes (ETTs). METHODS: We applied 2 h of ALT to a P. aeruginosa biofilm in ETTs using a single dose (SD) and a 5-day therapy model (5D). We used sterile saline lock therapy (SLT) as the positive control. We compared colony count and the percentage of live cells between both models. RESULTS: The median (IQR) cfu counts/ml and percentage of live cells in the SD-ALT and SD-SLT groups were, respectively, 3.12 × 105 (9.7 × 104-0) vs. 8.16 × 107 (7.0 × 107-0) (p = 0.05) and 53.2% (50.9%-57.2%) vs. 91.5% (87.3%-93.9%) (p < 0.001). The median (IQR) cfu counts/ml and percentage of live cells in the 5D-ALT and 5D-SLT groups were, respectively, 0 (0-0) vs. 3.2 × 107 (2.32 × 107-0) (p = 0.03) and 40.6% (36.6%-60.0%) vs. 90.3% (84.8%-93.9%) (p < 0.001). CONCLUSION: We demonstrated a statistically significant decrease in the viability of P. aeruginosa biofilm after application of 5D-ALT in the SS. Future clinical studies to assess ALT in patients under mechanical ventilation are needed.

Quality of the aetiological diagnosis of ventilator-associated pneumonia in Spain in the opinion of intensive care specialists and microbiologists.

INTRODUCTION: Current guidelines for the microbiological diagnosis of ventilator-associated pneumonia (VAP) are imprecise. Based on data provided by intensive care specialists (ICS) and microbiologists, this study defines the clinical practices and microbiological techniques currently used for an aetiological diagnosis of VAP and pinpoints deficiencies. METHODS: Eighty hospitals in the national health network with intensive care and microbiology departments were sent two questionnaires, one for each department, in order to collect data on VAP diagnosis for the previous year. RESULTS: Out of the 80 hospitals, 35 (43.8%) hospitals participated. These included 673 ICU beds, 32,020 ICU admissions, 173,820 ICU days stay, and generated 27,048 lower respiratory tract specimens in the year. A third of the hospitals (35%) had a microbiology department available 24/7. Most samples (83%) were tracheal aspirates. Gram stain results were immediately reported in around half (47%) of the hospitals. Quantification was made in 75% of hospitals. Molecular techniques and direct susceptibility testing were performed in 12% and one institution, respectively. Mean turnaround time for a microbiological report was 1.7 (SD; 0.7), and 2.2 (SD; 0.6) days for a negative and positive result, respectively. Telephone/in-person information was offered by 65% of the hospitals. Most (89%) ICS considered microbiological information as very useful. No written procedures were available in half the ICUs. CONCLUSIONS: Both ICS and microbiologists agreed that present guidelines for the diagnosis of VAP could be much improved, and that a new set of consensus guidelines is urgently required. A need for guidelines to be more effectively implemented was also identified in order to improve outcomes in patients with VAP.

Vascular catheter colonization: surveillance based on culture of needleless connectors.

BACKGROUND: Superficial culture has a high negative predictive value in the assessment of catheter tip colonization (CC) and catheter-related bloodstream infection (C-RBSI). However, the process of hub culture requires the hubs to be swabbed, and this carries a risk of dislodging the biofilm. At present, most catheter hubs are closed by needleless connectors (NCs) that are periodically replaced. Our objective was to compare the yield of SC (skin + hub culture) with that of skin + NC culture in the assessment of CC and C-RBSI. METHODS: During 5 months, we included the patients on the Major Heart Surgery ICU when a central venous catheter (CVC) remained in place ≥7 days after insertion. SCs were taken simultaneously when the NC was withdrawn and processed by the semi-quantitative method, even when the catheter was not removed. All catheter tips were cultured. All NCs belonging to a single catheter lumen were individually flushed with 100 µl of brain-heart infusion (BHI) broth. We considered the lumen to be colonized when ≥1 NC culture from the lumen flush was positive. We collected a total of 60 catheters. RESULTS: The overall CC rate was 15.0 %, and we confirmed two episodes of C-RBSI. The validity values after the comparison of SCs with skin + NC culture for prediction of CC were the following: sensitivity 66.7 % vs. 77.8 %, and negative predictive value 93.6 % vs. 93.1 %. The sensitivity and negative predictive value for prediction of C-RBSI was 100 % for both SC and skin + NC culture. CONCLUSION: The combination of skin and flushed NC culture can be an alternative to conventional SC for ruling out CC and C-RBSI.

Assessment of central venous catheter colonization using surveillance culture of withdrawn connectors and insertion site skin.

BACKGROUND: Culture of catheter hubs and skin surrounding the catheter entry site has a negative predictive value for catheter tip colonization. However, manipulation of the hub for culture requires the hubs to be swabbed, introducing potential dislodging of biofilm and subsequent migration of microorganisms. Hubs are usually closed with needleless connectors (NCs), which are replaced regularly. Our objective was to evaluate whether culture of flushed withdrawn NCs is an alternative to hub culture when investigating central venous catheter colonization. METHODS: The study population comprised 49 intensive care unit patients whose central venous catheters had been in place for at least 7 days. Cultures of NCs and skin were obtained weekly. RESULTS: We included 82 catheters with more than 7 days' indwelling time. The catheter tip colonization rate was 18.3% (15/82). Analysis of skin and NC cultures revealed a 92.5% negative predictive value for catheter colonization. Three episodes of catheter-related bloodstream infection (C-RBSI) occurred in patients with colonized catheters. CONCLUSION: Surveillance of NC and skin cultures could help to identify patients at risk for C-RBSI.

Cultures of Needleless Connectors Are Useful for Ruling Out Central Venous Catheter Colonization.

Semiquantitative cultures of skin surrounding intravascular catheter entry sites and catheter hubs have high negative predictive values for catheter tip colonization. However, culturing samples from the inner side of the hub requires the catheter to be manipulated, thus increasing the risk of migration of microorganisms into the bloodstream. Today, hubs are closed using needleless connectors (NCs). Cultures of NCs could predict catheter colonization. Our objective was to compare the yield of NC sonicate cultures for prediction of catheter colonization with that of hub cultures. For 6 months, we prospectively collected all short-term central lines and systems removed from patients admitted to the cardiac surgery postoperative care unit, irrespective of the reason for withdrawal. Hub cultures were obtained immediately before withdrawal and were cultured using a semiquantitative method. Catheter tips were cultured using the roll-plate technique and sonication, and NCs were cultured using a semiquantitative technique after sonication. We considered NCs to be colonized when ≥1 culture was positive. We collected a total of 75 central systems. The catheter colonization rate was 10.7%. The rates for hub and NC colonization were 6.7% and 12.0%, respectively. The validity values for hubs and NCs for prediction of catheter colonization were as follows: sensitivity, 25.0% and 87.5%; specificity, 95.5% and 97.0%; positive predictive value, 40.0% and 77.8%; negative predictive value, 91.4% and 98.5%; validity index, 88.0% and 96.0%, respectively. Cultures of closed NCs can be used to rule out catheter tip colonization and are superior to hub cultures in ruling out short-term central venous catheter colonization.

Impact of four sequential measures on the prevention of ventilator-associated pneumonia in cardiac surgery patients.

INTRODUCTION: Ventilator-associated pneumonia (VAP) is the most frequent infection in patients admitted to intensive care units. METHODS: We compared rates of VAP, days on mechanical ventilation (MV), and cost of antimicrobial agents before and during implementation. RESULTS: We collected data from 401 patients before the intervention and from 1,534 patients during the intervention. Both groups were comparable. No significant differences in EuroSCORE were observed between the patients of both periods (6.4 versus 6.3; P = 0.7). The rates of VAP (episodes/1,000 days of ventilation) were, respectively, 23.9 versus 13.5 (P = 0.005). Mean number of days of MV/1,000 days of stay was 507 versus 375 (P = 0.001), and the cost of antimicrobial therapy (Euros/1,000 days of stay) was €70,612 versus €52,775 (P = 0.10). The main effect of sequential application of preventive measures in time achieved a relative-rate reduction of VAP of 41% (IRR, 0.41; 95% CI, 0.28 to 0.62). The mortality rate before and during the intervention was 13.0% and 10.2%, respectively. CONCLUSIONS: A sequentially applied bundle of four preventive measures reduces VAP rates, days of MV, and the cost of antimicrobial therapy in patients admitted to the major heart surgery ICU. TRIAL REGISTRATION: Clinical Trials.gov: NCT02060045. Registered 4 February 2014.

Addressing catheter lock therapy: Does heparin reduce the bioactivity of dalbavancin when together in solution during freezing?

INTRODUCTION: The possible use of dalbavancin as a catheter lock solution was previously demonstrated by our study group. However, it was needed to assess whether heparin could affect dalbavancin bioactivity during freezing storage. METHODS: We tested the bioactivity of a dalbavancin+heparin (DH) vs. dalbavancin (D) against Staphylococcal biofilms comparing DH median value of cfu counts and metabolic activity with that obtained for D before and during storage under freezing up to 6 months. RESULTS: Despite there was a slight decrease in the median percentage reduction of metabolic activity at month 3 in Staphylococcus epidermidis between DH and D (97.6 vs. 100, p=0.037), considering the clinical criteria, no significant reduction in any of the variables tested was observed at the end of the experiment between D and DH solutions. CONCLUSION: The addition of heparin to a dalbavancin lock solution did not affect its bioactivity against staphylococcal biofilms irrespective of its preservation time under freezing.

Impact of the COVID-19 pandemic on the incidence and the epidemiology of catheter-related bloodstream infection two years later.

Introduction: The COVID-19 pandemic increased catheter-related bloodstream infections (C-RBSI), but its subsequent impact has not been adequately described. Our hospital has already depicted the effects of the COVID-19 pandemic in the first wave. However, we still do not know whether C-RBSI rates and aetiology are similar to those described before the COVID-19 pandemic. We aimed to evaluate the impact of the COVID-19 pandemic on the evolution of C-RBSI in a large tertiary teaching hospital two years later. Material and methods: We prospectively collected all confirmed C-RBSI episodes in a clinical microbiology laboratory database by matching blood cultures and catheter tip cultures with the isolation of the same microorganism (s). We compared our C-RBSI incidence rates and aetiology from 2018 to 2023. C-RBSI was defined as bacteremia or fungemia in a patient with clinical manifestations of infection and no other apparent source except the catheter. Results: During the study period, we collected 556 C-RBSI episodes. C-RBSI incidence rate per 1000 admissions each year was as follows: 2018: 2.2; 2019: 1.7; 2020: 3.29; 2021: 2.92; 2022: 2.69. and 2023: 2.01. Mainly, C-RBSI episodes occurring in critical care units each year were, respectively: 2018: 57 (54.8 %), 2019: 38 (45.2 %), 2020: 89 (63.6 %), 2021: 69 (60.5 %), 2022: 58 (50.9 %) and 2023 (61.4 %). The distribution of microorganisms showed an increase in Gram-negative episodes after the pandemic. Conclusion: Our study shows an increase in the incidence rate of C-RBSI during the COVID-19 pandemic, with a discrete decrease after that. C-RBSI episodes were mainly caused by coagulase-negative Staphylococci but with a rise in Gram-negative bacilli.

Production of biofilm by Staphylococcus aureus: Association with infective endocarditis?

OBJECTIVES: Staphylococcus aureus is a well-known biofilm-producing pathogen that is capable of causing chronic infections owing to its ability to resist antibiotic treatment and obstruct the immune response. However, the possible association between high biofilm production and infective endocarditis (IE) has not been assessed. Our objective was to compare production of biofilm by S. aureus strains isolated from patients with bacteremia and IE, catheter-related bloodstream infection (C-RBSI), or non-device associated bacteremia. METHODS: We isolated 260 S. aureus strains from the blood of patients with bacteremia who were diagnosed during hospital admission between 2012 and 2015. Patients were divided into 3 groups according to whether they had IE, C-RBSI, or non-device associated bacteremia. Biofilm production was measured in terms of biomass and metabolic activity using the crystal violet and XTT assays, respectively. High biomass and metabolic activity rates (based on tertile ranks classification) were compared between the 3 groups. RESULTS: The high biomass and metabolic activity rates of each group were 41.9% and 37.2% for IE, 32.5% and 35.0%, for C-RBSI, and 29.0% and 33.3% for non-device associated bacteremia (p=0.325 and p=0.885, respectively). CONCLUSIONS: High biomass and metabolic activity levels for S. aureus isolates from IE were similar to those of S. aureus isolates from C-RBSI or non-device associated bacteremia.

Production of biofilm by Staphylococcus aureus: Association with infective endocarditis?

OBJECTIVES: Staphylococcus aureus is a well-known biofilm-producing pathogen that is capable of causing chronic infections owing to its ability to resist antibiotic treatment and obstruct the immune response. However, the possible association between high biofilm production and infective endocarditis (IE) has not been assessed. Our objective was to compare production of biofilm by S. aureus strains isolated from patients with bacteremia and IE, catheter-related bloodstream infection (C-RBSI), or non-device associated bacteremia. METHODS: We isolated 260 S. aureus strains from the blood of patients with bacteremia who were diagnosed during hospital admission between 2012 and 2015. Patients were divided into 3 groups according to whether they had IE, C-RBSI, or non-device associated bacteremia. Biofilm production was measured in terms of biomass and metabolic activity using the crystal violet and XTT assays, respectively. High biomass and metabolic activity rates (based on tertile ranks classification) were compared between the 3 groups. RESULTS: The high biomass and metabolic activity rates of each group were 41.9% and 37.2% for IE, 32.5% and 35.0%, for C-RBSI, and 29.0% and 33.3% for non-device associated bacteremia (p=0.325 and p=0.885, respectively). CONCLUSIONS: High biomass and metabolic activity levels for S. aureus isolates from IE were similar to those of S. aureus isolates from C-RBSI or non-device associated bacteremia.

How should microbiology laboratories interpret cultures of the sonicate of closed needleless connectors?

INTRODUCTION: Our objective was to determine whether there is a cut-off in the needleless connectors' (NCs) cultures that when combined with skin cultures it was as efficient as conventional superficial cultures to rule-out catheter colonization (CC) and catheter-related bloodstream infection (CRBSI). METHODS: During 10 months, we collected samples and then we analyzed the validity values of skin+NCs cultures for CC and CRBSI considering the best cut-off showing at least >90% of specificity to have a high negative predictive value using a ROC curve. RESULTS: We collected a total of 167 catheters. The optimal cut-off of NCs culture was 1000cfu/NC. The validity values for CC and CRBSI combining skin cultures and NCs cultures using the selected cut-off were, respectively: S, 42.9%/16.7%; SP, 83.6%/75.8%; PPV, 27.3%/2.5%; and NPV, 91.0%/96.0%. CONCLUSIONS: The combination of skin cultures and quantitative NCs cultures could be used for ruling-out CC and CRBSI.