Bacteremic complications of intravascular catheters colonized with Staphylococcus aureus

Management of Staphylococcus aureus Bloodstream Infections

Staphylococcus aureus bloodstream infections are associated with a high morbidity and mortality. Nevertheless, significance of a positive blood culture with this pathogen is often underestimated or findings are misinterpreted as contamination, which can result in inadequate diagnostic and therapeutic consequences. We here review and discuss current diagnostic and therapeutic key elements and open questions for the management of Staphylococcus aureus bloodstream infections.

Dwindling Utilization of Central Venous Catheter Tip Cultures: An Analysis of Sampling Trends and Clinical Utility at 128 US Hospitals, 2009-2014

At 128 US hospitals, from 2009-2014, a 17% decline occurred annually in central venous catheter tips sent for culture: a 6-fold decrease from blood culture sampling trends. The positive predictive value was low (23%). Tip culture use often does not conform to recommendations and offers limited independent treatment opportunities.

Expert consensus-based clinical practice guidelines management of intravascular catheters in the intensive care unit

The French Society of Intensive Care Medicine (SRLF), jointly with the French-Speaking Group of Paediatric Emergency Rooms and Intensive Care Units (GFRUP) and the French-Speaking Association of Paediatric Surgical Intensivists (ADARPEF), worked out guidelines for the management of central venous catheters (CVC), arterial catheters and dialysis catheters in intensive care unit. For adult patients: Using GRADE methodology, 36 recommendations for an improved catheter management were produced by the 22 experts. Recommendations regarding catheter-related infections’ prevention included the preferential use of subclavian central vein (GRADE 1), a one-step skin disinfection(GRADE 1) using 2% chlorhexidine (CHG)-alcohol (GRADE 1), and the implementation of a quality of care improvement program. Antiseptic- or antibiotic-impregnated CVC should likely not be used (GRADE 2, for children and adults). Catheter dressings should likely not be changed before the 7th day, except when the dressing gets detached, soiled or impregnated with blood (GRADE 2− adults). CHG dressings should likely be used (GRADE 2+). For adults and children, ultrasound guidance should be used to reduce mechanical complications in case of internal jugular access (GRADE 1), subclavian access (Grade 2) and femoral venous, arterial radial and femoral access (Expert opinion). For children, an ultrasound-guided supraclavicular approach of the brachiocephalic vein was recommended to reduce the number of attempts for cannulation and mechanical complications. Based on scarce publications on diagnostic and therapeutic strategies and on their experience (expert opinion), the panel proposed definitions, and therapeutic strategies.

Whole-genome sequencing to explore nosocomial transmission and virulence in neonatal methicillin-susceptible Staphylococcus aureus bacteremia

BACKGROUND

Neonatal Staphylococcus aureus (S. aureus) bacteremia is an important cause of morbidity and mortality. In this study, we examined whether methicillin-susceptible S. aureus (MSSA) transmission and genetic makeup contribute to the occurrence of neonatal S. aureus bacteremia.

METHODS

A retrospective, single-centre study was performed. All patients were included who suffered from S. aureus bacteremia in the neonatal intensive care unit (NICU), Erasmus MC-Sophia, Rotterdam, the Netherlands, between January 2011 and November 2017. Whole-genome sequencing (WGS) was used to characterize the S. aureus isolates, as was also done in comparison to reference genomes. Transmission was considered likely in case of genetically indistinguishable S. aureus isolates.

RESULTS

Excluding coagulase-negative staphylococci (CoNS), S. aureus was the most common cause of neonatal bacteremia. Twelve percent (n = 112) of all 926 positive blood cultures from neonates grew S. aureus. Based on core genome multilocus sequence typing (cgMLST), 12 clusters of genetically indistinguishable MSSA isolates were found, containing 33 isolates in total (2-4 isolates per cluster). In seven of these clusters, at least two of the identified MSSA isolates were collected within a time period of one month. Six virulence genes were present in 98-100% of all MSSA isolates. In comparison to S. aureus reference genomes, toxin genes encoding staphylococcal enterotoxin A (sea) and toxic shock syndrome toxin 1 (tsst-1) were present more often in the genomes of bacteremia isolates.

CONCLUSION

Transmission of MSSA is a contributing factor to the occurrence of S. aureus bacteremia in neonates. Sea and tsst-1 might play a role in neonatal S. aureus bacteremia.

Should central venous catheters be rapidly removed to treat Staphylococcus aureus related-catheter bloodstream infection (CR-BSI) in neonates and children? An 8-year period (2010-2017) retrospective analysis in a French University Hospital

Catheter-related bloodstream infection (CR-BSI) treatment is based on empiric antibiotherapy associated with or without catheter removal. The aim of this study was to compare the incidence of failures in neonates and children with Staphylococcus aureus CR-BSI with or without rapid catheter removal. Treatment failure was defined as the persistence of positive blood cultures, onset or aggravation of a local or systemic complication, or relapse. Fifty-four CR-BSI in 225 patients were analysed (33 and 21 conservative and non-conservative treatments) with three and 10 failures, respectively (P<0.002). Non-conservative treatment with rapid catheter removal seems to be associated with a significantly lower failure rate and should be recommended.

Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC)

Catheter-related bloodstream infections (CRBSI) constitute an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. The aim of these guidelines is to provide updated recommendations for the diagnosis and management of CRBSI in adults. Prevention of CRBSI is excluded. Experts in the field were designated by the two participating Societies (the Spanish Society of Infectious Diseases and Clinical Microbiology and [SEIMC] and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units [SEMICYUC]). Short-term peripheral venous catheters, non-tunneled and long-term central venous catheters, tunneled catheters and hemodialysis catheters are covered by these guidelines. The panel identified 39 key topics that were formulated in accordance with the PICO format. The strength of the recommendations and quality of the evidence were graded in accordance with ESCMID guidelines. Recommendations are made for the diagnosis of CRBSI with and without catheter removal and of tunnel infection. The document establishes the clinical situations in which a conservative diagnosis of CRBSI (diagnosis without catheter removal) is feasible. Recommendations are also made regarding empirical therapy, pathogen-specific treatment (coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus spp., Gram-negative bacilli, and Candida spp.), antibiotic lock therapy, diagnosis and management of suppurative thrombophlebitis and local complications.

A state of the art review on optimal practices to prevent, recognize, and manage complications associated with intravascular devices in the critically ill

Intravascular catheters are inserted into almost all critically ill patients. This review provides up-to-date insight into available knowledge on epidemiology and diagnosis of complications of central vein and arterial catheters in ICU. It discusses the optimal therapy of catheter-related infections and thrombosis. Prevention of complications is a multidisciplinary task that combines both improvement of the process of care and introduction of new technologies. We emphasize the main component of the prevention strategies that should be used in critical care and propose areas of future investigation in this field.

Efficacy of routine catheter tip culture in a neonatal intensive care unit

BACKGROUND

Routine catheter tip cultures are not recommended because some cases of colonization, such as with Staphylococcus aureus, can lead to subsequent bacteremia. To evaluate the safety of colonization without antimicrobial treatment, as well as the effectiveness of routine catheter tip cultures in the neonatal intensive care unit (NICU), we performed a retrospective data analysis in a Japanese community hospital.

METHODS

We reviewed all peripherally inserted central venous catheter tip culture results from the NICU ward between April 2012 and June 2017 and noted outcome (i.e. antimicrobial treatment or subsequent infection). We then performed a cost analysis for routine catheter tip culturing on patients who were symptom free during the study period.

RESULTS

Of the 93 positive cases in 80 patients from 1,051 catheter tip cultures, seven patients had suspected infection and were treated with antimicrobials. The other 73 symptom-free, positive patients had no subsequent or exacerbated symptoms indicative of an infection, and did not have antimicrobial treatment. The total cost for catheter tip culturing during the study period was ¥548 731. After excluding patients with symptoms of infection at the time of culture, the efficacy of routine catheter tip cultures on symptom-free patients was estimated to be zero.

CONCLUSION

Symptom-free colonization did not affect clinician management in this study, and all colonized patients without suspected infection were safely managed without antimicrobials. Furthermore, routine catheter tip culturing was not cost-effective; therefore, this practice may be no longer recommended in the NICU.

Low incidence of subsequent bacteraemia or fungaemia after removal of a colonized intravascular catheter tip

OBJECTIVES

We determined the frequency of subsequent bloodstream infection more than 2 days after removal of a catheter with positive tip cultures.

METHODS

We conducted a nationwide, observational study on intravascular catheter (IVC) tip cultures in Switzerland from 2008 to 2015 using data from the Swiss Antibiotic Resistance Surveillance System (ANRESIS). An IVC tip culture was included in the analysis if at least one microorganism could be cultivated from it. We excluded all data from patients with concurrent bacteraemia with the same microorganism identified 7 days before to 2 days after IVC removal. Subsequent bloodstream infection was defined as isolating (from blood cultures performed more than 2 days up to 7 days after catheter removal) the same microorganism as the one recovered from the IVC. Data on antibiotic therapy were not available in this surveillance study.

RESULTS

Over the 8-year period, 15 033 positive IVC tip cultures were identified. Our study population comprised 12 513 episodes of positive IVC tip cultures without concurrent bacteraemia. The frequency of sBSI was 1.8% (n = 219). Subsequent bloodstream infections were more frequently detected after identification of C. albicans (10/113, 8.8%), S. marcescens (9/169, 5.3%), and S. aureus (30/623, 4.8%) on a catheter tip.

CONCLUSIONS

A very low incidence of subsequent bloodstream infection was observed if a microorganism was identified on a removed IVC tip without concurrent bacteraemia. The risk of subsequent bloodstream infection increased if C. albicans, S. aureus, or S. marcescens were identified in this context.

Should non-bacteraemic patients with a colonized catheter receive antimicrobial therapy?

OBJECTIVES

The impact of antimicrobial therapy on the outcomes of patients with colonized catheters and no bacteraemia has not been assessed. This study assessed whether targeted antibiotic therapy is related to a poor outcome in patients with positive cultures of blood drawn through a non-tunnelled central venous catheter (CVC) and without concomitant bacteraemia.

METHODS

This was a retrospective study involving adult patients with positive blood cultures drawn through a CVC and negative peripheral vein blood cultures. Patients were classified into two groups: those with clinical improvement and those with a poor outcome. These two groups were compared. The outcome was considered poor in the presence of one or more of the following: death, bacteraemia or other infection due to the same microorganism, and evidence of catheter-related bloodstream infection.

RESULTS

A total of 100 patients were included (31 with a poor outcome). The only independent predictors of a poor outcome were a McCabe and Jackson score of 1-2 and a median APACHE score of 5. No association was found between the use of targeted antimicrobial therapy and a poor outcome when its effect was adjusted for the rest of the variables.

CONCLUSIONS

This study showed that antimicrobial therapy was not associated with a poor outcome in non-bacteraemic patients with positive blood cultures drawn through a CVC.

Significance of the isolation of Staphylococcus aureus from a central venous catheter tip in the absence of concomitant bacteremia: a clinical approach

The optimal approach following the isolation of Staphylococcus aureus from an intravascular catheter tip in the absence of concomitant bacteremia remains unclear. We aimed to determine the rate of delayed complications in these patients. We performed a retrospective observational study (during the period 2002-2012) including patients with a catheter tip culture yielding S. aureus. Patients were followed up for ≥6 months. The primary endpoint was the occurrence of delayed staphylococcal complications (either bacteremia and/or metastatic distant infections). A total of 113 patients were included (75 % male, median age 61 years): 46 and 67 with negative and positive blood cultures, respectively. We found a lower rate of delayed staphylococcal complications in cases with no bacteremia within 48 h since catheter removal than in cases of confirmed S. aureus catheter-related bacteremia (0.0 % vs. 25.4 %; p-value < 0.001). In the group without bacteremia, there was a subgroup of 15 patients (32.6 %) who did not receive antimicrobial treatment. Again, delayed complications occurred less commonly in this subgroup of patients without bacteremia (0.0 % vs. 25.4 %; p-value = 0.033). In contrast to patients with S. aureus catheter-related bacteremia, no delayed infectious complications were observed in patients with an isolated catheter tip culture yielding S. aureus and negative blood cultures within 48 h of catheter removal. Futures studies are needed to assess if the therapeutic approach could be different for this group of patients.

How to use central venous catheter tip cultures

Central venous catheter (CVC) tip cultures are useful in the assessment of a patient with a potential catheter-related bloodstream infection (CRBSI). However, these results can be misleading particularly in the absence of concomitant peripheral and central line blood cultures. Catheter tip cultures should not be submitted to the laboratory unless CRBSI is suspected as the predictive value of culture results depends on the pretest probability of CRBSI. A positive CVC tip culture does not usually warrant further investigation or therapy (except in the case of Staphylococcus aureus and possibly Candida sp) while a negative catheter tip culture in isolation does not definitively exclude CRBSI. Clinicians can use alternative criteria for the diagnosis of CRBSI that do not require catheter tip cultures if necessary. Further research into the significance of CVC tip cultures in the absence of concomitant bacteraemia is required.

Positive tip culture with Candida and negative blood culture: to treat or not to treat? A systematic review with meta-analysis

BACKGROUND

Invasive candidiasis is a major invasive fungal infection. It has high lethality, and even higher if not treated early. There is no consensus on antifungal treatment in patients with positive catheter tip culture for Candida spp. The objective of this study was to evaluate the impact of antifungal therapy and mortality of patients with positive culture for Candida spp. in catheter tip that have negative blood culture.

METHODS

The PubMed database was searched to identify articles related to Candida and catheter. Articles with adequate data were included.

RESULTS

Of 1208 studies initially screened, 5 met the selection criteria. All were retrospective studies. In all, 265 patients were evaluated for outcomes 'candidemia' and 'invasive candidiasis' and 158 for the outcome 'mortality.' Antifungal therapy had no impact on the development of invasive fungal disease (Odds ratio (OR) = 1.41; 95% confidence interval (CI) = 0.56-3.52). Also there was no benefit of therapy on mortality (OR = 1.02; 95% CI = 0.54-1.95).

CONCLUSION

Due to the poor quality of the studies no conclusion can be made. Randomized prospective studies are needed to better evaluate this therapeutic strategy.

Catheter-related and infusion-related sepsis

This article focuses on the pathogenesis, diagnosis, prevention, and management of infectious complications of intravascular cannulation and fluid infusion. Although continuous vascular access is one of the most essential modalities in modern-day medicine, there is a substantial and underappreciated potential for producing iatrogenic complications, the most important of which is blood-borne infection. Clinicians often fail to consider the diagnosis of infusion-related sepsis because clinical signs and symptoms are indistinguishable from bloodstream infections arising from other sites. Understanding and consideration of the risk factors predisposing patients to infusion-related infections may guide the development and implementation of control measures for prevention.

The risk of catheter-related bloodstream infection after withdrawal of colonized catheters is low

Most episodes of catheter-related bloodstream infection (C-RBSI) are documented before or at the time of catheter withdrawal. The risk of C-RBSI in the period after removing a colonized catheter in patients without bacteremia (late C-RBSI) is unknown. We assessed the risk of developing a late C-RBSI episode in an unselected population with positive catheter tip cultures and analyzed associated risk factors. We analyzed retrospectively all colonized catheter tips between 2003 and 2010 and matched them with blood cultures. C-RBSI episodes were classified as early C-RBSI (positive blood cultures were obtained ≤24 h after catheter withdrawal) or late C-RBSI (positive blood cultures were obtained ≥24 h after catheter withdrawal). We analyzed the risk factors associated with late C-RBSI episodes by comparison with a selected group of early C-RBSI episodes. We collected a total of 17,981 catheter tips: 4,533 (25.2 %) were colonized. Of them, 1,063 (23.5 %) were associated to early C-RBSI episodes and from the remaining 3,470, only 143 (4.1 %) were associated to late C-RBSI episodes. Then, they corresponded to 11.9 % of the total 1,206 C-RBSI episodes. After comparing early and late C-RBSI episodes, we found that late C-RBSI was significantly associated with the presence of methicillin-resistant Staphylococcus aureus (MRSA, p = 0.028) and with higher mortality (p = 0.030). According to our data, patients with colonized catheter tips had a 4.1 % risk of developing late C-RBSI, which was associated with higher crude mortality.

Delayed peripheral venous catheter-related Staphylococcus aureus bacteremia: onset ≥ 24 hours after catheter removal

Peripheral venous catheter (PVC)-associated bacteremia usually develops during the indwelling period. We present a review of 14 patients who developed delayed onset Staphylococcus aureus bacteremia (D-SAB), 1-6 days after PVC removal, and compare them to 29 patients with early onset PVC-related S. aureus bacteremia (E-SAB). At the time of removal, the catheter site exhibited inflammation in 8 (57.1%) cases. At SAB onset, PVC site inflammation developed in all patients. Compared to E-SAB, patients with D-SAB were more often aged ≥ 65 y (71.4% vs. 34.5%; p = 0.03) and on corticosteroids (35.7% vs. 6.9%; p = 0.02). D-SAB was more complicated with persistent (> 3 days) bacteremia (42.9% vs. 13.8%; p = 0.04), metastatic infections (35.7% vs. 6.9%; p = 0.02), and slightly higher mortality (21.4% vs. 10.3%; p = 0.3). Logistic regression revealed that the predictors of D-SAB were corticosteroids (odds ratio (OR) 2.10, 95% confidence intervals (CI) 1.16-58.61) and age ≥ 65 y (OR 1.63, 95% CI 1.12-23.30). These patients may have impaired local/systemic defenses that lead to D-SAB, or a blunted host response with delayed recognition.

Clinical significance of Candida colonization of intravascular catheters in the absence of documented candidemia

In order to assess the significance of Candida colonization of intravascular catheters (IVC) in patients without documented candidemia, we retrospectively reviewed all Candida-positive IVC tip cultures over a 4-year period. Cases were defined as those with a culture yielding ≥15 colony-forming units of Candida spp. that either did not have blood cultures (BC) taken or had concomitant BC negative for Candida. Patients were followed up until death or 8 months after discharge. Risk factors for poor outcome following IVC removal (death, candidemia, or Candida-related complication) were analyzed. We analyzed a total of 40 patients. Overall mortality was 40.0%, with no death directly attributed to Candida infection. Twenty-two patients received antifungal therapy at the time of IVC removal. Only 1 patient developed a metastatic complication (chorioretinitis) attributable to transient candidemia (2.5% of the global cohort and 3.7% among those with concomitant BC). There were no cases of subsequent candidemia. In the multivariate analysis, the use of antifungal therapy did not show any impact on the risk of poor outcome. The risk of invasive disease in patients with isolated IVC colonization by Candida seems to be low. Nevertheless, the initiation of systemic antifungal therapy should be carefully considered in such context.

Managing intravascular catheter-related infections in heart transplant patients: how far can we apply IDSA guidelines for immunocompromised patients?

PURPOSE OF REVIEW

This study discusses the applicability to heart transplant patients of recently issued guidelines on the diagnosis, management and prevention of catheter-related bloodstream infections (CR-BSIs). It also updates newly available information of possible interest to the care of heart transplant patients.

RECENT FINDINGS

Catheters remain the leading cause of early bloodstream infections in heart transplant patients. The cause of CR-BSI is mainly attributable to Gram-positive microorganisms. Very frequently, the origin of a bloodstream infection in a heart transplant patient with multiple catheters is not clear, and a precise diagnosis is required. Management without catheter removal may be undertaken when indicated. Empiric therapy should cover Gram-positive, multidrug resistant and Gram-negative bacteria along with Candida. Prolonged antibiotic treatment exceeding 14 days is recommended and should be continued up to 4-6 weeks in the case of Staphylococcus aureus. Prevention measures include education and training, maximal sterile barrier precautions during catheter insertion, a 2% chlorhexidine preparation for skin antisepsis, avoiding routine replacement of catheters and using antimicrobial/antiseptic impregnated short-term central vein catheters (CVCs) and chlorhexidine sponge dressings.

SUMMARY

Until confirmatory data are obtained, present guidelines for diagnosing, managing and preventing CR-BSI can be applied to heart transplant patients. We would nevertheless highlight that the additional precautions should be taken of broader empiric antimicrobial therapy followed by longer duration treatment in these patients.

Central venous catheter colonization with Staphylococcus aureus is not always an indication for antimicrobial therapy

Whether patients whose catheter tip grows Staphylococcus aureus but who have no concomitant bacteraemia should receive antimicrobials remains an unresolved issue. However, a proportion of patients with catheter tips colonized by S. aureus have no blood cultures taken because of low suspicion of sepsis and the meaning of this microbiological finding is unknown. We have analysed all catheter tips growing S. aureus during a 6-year period and have selected patients without blood cultures taken 7 days before or after central vascular catheter removal. Patient's evolution was classified into good and poor outcome. Poor outcome was defined as S. aureus infection within 3 months after catheter withdrawal or death in the same period with no obvious cause. Patients with good and poor outcomes were compared to assess whether antimicrobial therapy influenced evolution. Sixty-seven patients fulfilled our inclusion criteria and five (7.4%) had a poor outcome. The administration of early anti-staphylococcal therapy had no impact on the outcome of this population (p 0.99). The only factor independently associated with a poor outcome was the presence of clinical signs of sepsis when the catheter was removed (OR 20.8; 95% CI 2.0-206.1; p 0.009). Our data suggest that patients with central vascular catheter tips colonized with S. aureus should be closely monitored for signs and symptoms of ongoing infection, but if these are not present then antimicrobial therapy does not seem justified.

Bacteremic complications of intravascular catheter tip colonization with Gram-negative micro-organisms in patients without preceding bacteremia

Although Gram-negative micro-organisms are frequently associated with catheter-related bloodstream infections, the prognostic value and clinical implication of a positive catheter tip culture with Gram-negative micro-organisms without preceding bacteremia remains unclear. We determined the outcomes of patients with intravascular catheters colonized with these micro-organisms, without preceding positive blood cultures, and identified risk factors for the development of subsequent Gram-negative bacteremia. All patients with positive intravascular catheter tip cultures with Gram-negative micro-organisms at the University Medical Center, Utrecht, The Netherlands, between 2005 and 2009, were retrospectively studied. Patients with Gram-negative bacteremia within 48 h before catheter removal were excluded. The main outcome measure was bacteremia with Gram-negative micro-organisms. Other endpoints were length of the hospital stay, in-hospital mortality, secondary complications of Gram-negative bacteremia, and duration of intensive care admission. A total of 280 catheters from 248 patients were colonized with Gram-negative micro-organisms. Sixty-seven cases were excluded because of preceding positive blood cultures, leaving 213 catheter tips from 181 patients for analysis. In 40 (19%) cases, subsequent Gram-negative bacteremia developed. In multivariate analysis, arterial catheters were independently associated with subsequent Gram-negative bacteremia (odds ratio [OR] = 5.00, 95% confidence interval [CI]: 1.20–20.92), as was selective decontamination of the digestive tract (SDD) (OR = 2.47, 95% CI: 1.07–5.69). Gram-negative bacteremia in patients who received SDD was predominantly caused by cefotaxime (part of the SDD)-resistant organisms. Mortality was significantly higher in the group with subsequent Gram-negative bacteremia (35% versus 20%, OR = 2.12, 95% CI: 1.00–4.49). Patients with a catheter tip colonized with Gram-negative micro-organisms had a high chance of subsequent Gram-negative bacteremia from any cause. This may be clinically relevant, as starting antibiotic treatment pre-emptively in high-risk patients with Gram-negative micro-organisms cultured from arterial intravenous catheters may be beneficial.

Bloodstream infection after positive catheter cultures: what are the risks in the intensive care unit when catheters are routinely cultured on removal?

OBJECTIVES

The aim of the study was to assess whether an isolated positive catheter culture is predictive of a subsequent bloodstream infection in intensive care unit patients.

DESIGN

Retrospective clinical study between 2000 and 2007.

SETTING

Intensive care unit of a university hospital.

SUBJECTS

All arterial, central venous, and dialysis catheters yielding selected pathogenic microorganisms from isolated positive catheter cultures. Positive catheter culture was defined by a catheter tip culture performed with the Brun-Buisson technique yielding ≥103 colony-forming units/mL; isolated positive catheter culture by a positive catheter culture without concomitant bloodstream infection due to the microorganism of the positive catheter culture evidenced within 48 hrs before or after catheter removal; and subsequent bloodstream infection by a bloodstream infection developing between 48 hrs and 30 days after catheter removal and due to a selected pathogenic microorganism of an isolated positive catheter culture. Active antibiotic therapy was active if at least one of the antibiotics administered was effective against the selected pathogenic microorganism of the positive catheter culture.

INTERVENTION

None.

MEASUREMENT AND MAIN RESULTS

The end point of the study was the ratio of the number of subsequent bloodstream infections to that of selected pathogenic microorganisms isolated from positive catheter culture 30 days after catheter removal. A total of 138 isolated positive catheter cultures for 149 selected pathogenic micro-organisms was included in the study. Only two cases (1.3%) of subsequent bloodstream infection were evidenced, one resulting from Escherichia coli and the other from Staphylococcus epidermidis. The incidence of subsequent bloodstream infection did not differ with regard to the presence or absence of active antibiotics at catheter removal: zero of 23 vs. two of 121 (p = 1), respectively.

CONCLUSIONS

Our results suggest that the risk of subsequent bloodstream infection in intensive care unit patients when the Brun-Buisson technique is used to define isolated positive catheter culture is low.

Preventing Staphylococcus aureus bacteremia and sepsis in patients with Staphylococcus aureus colonization of intravascular catheters: a retrospective multicenter study and meta-analysis

Two previous studies in tertiary care hospitals identified Staphylococcus aureus colonization of intravascular (IV) catheters as a strong predictor of subsequent S. aureus bacteremia (SAB), even in the absence of clinical signs of systemic infection. Bacteremia was effectively prevented by timely antibiotic therapy. We conducted this study to corroborate the validity of these findings in non-university hospitals.Using the laboratory information management systems of the clinical microbiology departments in 6 Dutch hospitals, we identified patients who had IV catheters from which S. aureus was cultured between January 1, 2003, and December 31, 2008. Patients with demonstrated SAB between 7 days before catheter removal and 24 hours after catheter removal were excluded. We extracted clinical and demographic patient data from the patients' medical records. The primary risk factor was initiation of anti-staphylococcal antibiotic therapy within 24 hours, and the primary endpoint was SAB >24 hours after IV catheter removal. Subsequently, we performed a systematic review and meta-analysis of all observational studies evaluating the effect of antibiotic therapy for S. aureus IV catheter tip colonization.In the current study, 18 of the 192 included patients developed subsequent SAB, which was associated with not receiving antibiotic therapy within 24 hours (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.1-15.6) and with documented exit-site infection (OR, 3.3; 95% CI, 1.2-9.3). When we combined these results with results of a previous study in a university hospital, a third risk factor was also associated with subsequent SAB, namely corticosteroid therapy (OR, 2.9; 95% CI, 1.3-6.3). We identified 3 other studies, in addition to the present study, in a systematic review. In the meta-analysis of these studies, antibiotic therapy yielded an absolute risk reduction of 13.6% for subsequent SAB. The number needed to treat to prevent 1 episode of SAB was 7.4.We conclude that early initiation of antibiotic therapy for IV catheters colonized with S. aureus prevents subsequent SAB.

Candidemic complications in patients with intravascular catheters colonized with Candida species: an indication for preemptive antifungal therapy?

BACKGROUND

The impact of Candida-colonized catheter tips in patients without candidemia is unclear.

METHODS

A retrospective study of patients with tip cultures positive for Candida was conducted over an 8-year period, to determine the outcomes in patients with Candida cultured from an intravascular catheter tip in the absence of preceding Candida-positive blood cultures. The primary outcome measure was definite candidemia. Secondary outcomes included possible candidemia and in-hospital mortality. A possible candidemia was defined as clinical signs and symptoms of invasive candidiasis without explanation other than a candidemia, but with negative blood cultures.

RESULTS

Sixty-eight cultures from 64 patients were included in the study. Definite candidemia developed in three cases (4%) and possible candidemia developed in five cases (7%). In-hospital mortality was significantly increased in patients with definite or possible candidemia (63% vs. 22%, p=0.028). Risk factors for the development of definite or possible candidemia were catheter time in situ >8 days (odds ratio (OR) 6.0, 95% confidence interval (CI) 1.1-32.9) and abdominal surgery (OR 6.0, 95% CI 1.1-32.4).

CONCLUSIONS

Intravascular catheter tip colonization in patients without preceding blood cultures with Candida is associated with candidemia in from 4% of patients (definite candidemia) up to 12% of patients (definite and possible candidemia combined). Considering the adverse prognosis associated with delayed treatment of candidemia, preemptive treatment based on catheter tip cultures might outweigh the disadvantages of costs and side effects of antifungal therapy.

Prospective, randomised study of selective versus routine culture of vascular catheter tips: patient outcome, antibiotic use and laboratory workload

In order to assess the value of vascular catheter tip culture in patients with negative blood cultures, all tip samples from hospitalised patients were prospectively randomised (1:1) to two different routines for processing catheters: culture of all tips (routine A) vs culture only of tips from patients with concomitant bacteraemia or fungaemia (routine B). Over a nine-month period, 426 catheters from 318 patients were randomly assigned to routine A and 429 catheters from 322 patients to routine B (n=40 [corrected] patients). We compared the outcome and costs from both groups. No statistically significant differences were found with respect to demographic data, mortality, hospital stay or antimicrobial use. In non-bacteraemic/fungaemic cases (N=517), days on antimicrobial therapy after catheter withdrawal were significantly higher in patients from group A [10.0 days (interquartile range, IQR): 6.0-14.0] vs 8.0 days (IQR: 4.7-12.2), P=0.03], as was the number of daily defined doses (DDDs) of antimicrobials [10.8 DDDs (IQR: 2.4-26.9) vs 7.5 DDDs (IQR: 1.5-20.0), P=0.03]. Median antimicrobial cost per treated patient was significantly higher in group A: €222.30 (IQR: €20.30-€1,030.60) vs €109.10 (IQR: €10.90-€653.20), P=0.05. If all vascular catheter tips were processed according to routine B, the microbiology laboratory workload would decrease by 77% for the total number of catheters processed. Microbiology laboratories should not routinely culture catheter tips in patients without bacteraemia or fungaemia.

Primary Staphylococcus aureus urinary tract infection: the role of undetected hematogenous seeding of the urinary tract

Staphylococcus aureus (SA) bacteriuria may accompany SA bacteremia, but primary SA urinary tract infection (UTI) may also occur. Our clinical observation of SA UTIs following intravenous catheter-related phlebitis lead us to review hematogenous and ascending route-related risk factors in patients with primary SA UTIs. The charts from all patients with SA UTIs over a 1.5-year period were reviewed for concurrent or recent hospitalization, intravenous catheterization, and for known UTI risk factors. Patients with concurrent SA bacteremia were excluded. Patients with Escherichia coli UTIs during the same period were included as controls. Twenty cases of primary SA UTI were compared with 43 E. coli UTI cases and they did not differ in age, diabetes mellitus, prostatic hypertrophy, previous UTI, or other urinary tract (UT) abnormality. However, cases were more likely than controls to have had recent or concurrent hospitalization, UT catheterization, and history of recent phlebitis. In multivariate analysis, UT catheterization and recent hospitalization retained significant association with SA UTI. Similar results were shown for the methicillin-resistant SA UTI subgroup. Even though UT catheterization is the main predisposing factor for primary SA UTI, some cases may be mediated through unrecognized preceding bacteremia related to intravascular device exposure or other healthcare-related factors.

Development of bacteraemia or fungaemia after removal of colonized central venous catheters in patients with negative concomitant blood cultures

There are limited data on the clinical significance of positive central venous catheter (CVC) tip cultures associated with concomitant negative blood cultures performed at the time of CVC removal. A retrospective cohort study of all patients who yielded isolated positive CVC tip cultures was conducted in a tertiary-care hospital with 2200 beds during a 10-year period. All patients with isolated positive CVC tip cultures were observed for the development of subsequent bacteraemia or fungaemia between 2 and 28 days after CVC removal. An isolated positive CVC tip culture was defined as a case in which (i) a CVC tip culture yielded > or = 15 colonies using a semiquantitative culture method and (ii) at least two sets of blood samples revealed no organism at, or close to, the time of CVC removal (48 h before to 48 h after CVC removal). During the study period, 312 patients with isolated positive CVC cultures were enrolled. Eight (2.6%; 95% CI 1.2-5.1) of the 312 patients yielding isolated bacterial or fungal CVC tip cultures developed subsequent bloodstream infection (BSI) caused by the same species as that isolated from the tip culture (Staphylococcus aureus, 1: Enterococcus spp.; 2: Pseudomonas aeruginosa; and 3: Candida spp.). Among 125 patients from whose CVC tips the above four organisms were grown, seven (12.3%) of 57 patients who did not receive appropriate antibiotic therapy within 48 h after CVC removal subsequently developed BSI, but only one (1.5%) of 68 patients who did receive appropriate therapy developed BSI (OR 0.11, p 0.02).

Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 Update by the Infectious Diseases Society of America

These updated guidelines replace the previous management guidelines published in 2001. The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them.

Staphylococcus aureus bacteraemia of unknown primary source: where do we stand?

There is no generally held definition of Staphylococcus aureus bacteraemia (SAB) of unknown source. For this paper, we consider it to occur when one or more positive blood cultures obtained from a patient grows S. aureus and the origin of the bacteraemia is uncertain after history, physical examination, chest radiography and any further investigations provoked by clinical findings. The incidence of SAB appears to be rising, particularly community-acquired (CA), but also hospital- or healthcare-acquired (HA). Major drivers appear to be intravenous drug use and increasing use of indwelling intravascular devices. There is an increasing prevalence of meticillin-resistant S. aureus (MRSA), both CA and HA. There is increasing hospital acquisition of MRSA that is phenotypically like CA strains, and there is increasing community-based treatment of HA infection. Metastatic infection is a risk of SAB. Infective endocarditis (IE) is a longstanding dreaded concern of SAB. Transoesophageal echocardiography appears to be a superior modality of recognising IE in the context of SAB and can guide the duration of therapy. Prosthetic joints and heart valves are at particular risk of haematogenous seeding from SAB. Implications of the rise of CA-MRSA in terms of metastatic infection warrant further study.