Is central venous catheter tips' colonization with multi-drug resistant Acinetobacter baumannii a predictor for bacteremia?

Healthcare Equipment and Personnel Reservoirs of Carbapenem-Resistant Acinetobacter baumannii Epidemic Clones in Intensive Care Units in a Tunisian Hospital

Carbapenem-resistant Acinetobacter baumannii (CRAB) strains can cause severe and difficult-to-treat infections in patients with compromised general health. CRAB strains disseminate rapidly in nosocomial settings by patient-to-patient contact, through medical devices and inanimate reservoirs. The occurrence of CRAB in patients residing in the intensive care units (ICUs) of the Sahloul University hospital in Sousse, Tunisia is high. The objective of the current study was to determine whether the surfaces of items present in five ICU wards and the medical personnel there operating could serve as reservoirs for CRAB strains. Furthermore, CRAB isolates from patients residing in the ICUs during the sampling campaign were analyzed for genome comparison with isolates from the ICUs environment. Overall, 206 items were screened for CRAB presence and 27 (14%) were contaminated with a CRAB isolate. The items were located in several areas of three ICUs. Eight of the 54 (15%) screened people working in the wards were colonized by CRAB on the hands. Patients residing in the ICUs were infected with CRAB strains sharing extensive genomic similarity with strains recovered in the nosocomial environment. The strains belonged to three sub-clades of the internationally disseminated clone (ST2). A clone emerging in the Mediterranean basin (ST85) was detected as well. The strains were OXA-23 or NDM-1 producers and were also pan-aminoglycoside resistant due to the presence of the armA gene. Hygiene measures are urgent to be implemented in the Sahloul hospital to avoid further spread of difficult-to-treat CRAB strains and preserve health of patients and personnel operating in the ICU wards.

Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options

Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.

Increased risk of catheter-related infection in critically ill patients given catecholamine inotropes during continuous renal replacement therapy

INTRODUCTION

Previous in vitro studies have shown that catecholamine inotropes are potent stimulators of bacterial growth and biofilm formation on catheter surfaces. This study aimed to investigate the effects of administering catecholamine inotropes during continuous renal replacement therapy (CRRT) on catheter-related infections in critically ill patients.

METHODS

This single-center retrospective cohort study included patients requiring CRRT in an intensive care unit from 2016 to 2017, who were divided into those who received and did not receive catecholamine inotropes for ≥24 h (catecholamine and control groups, respectively). The primary endpoint was catheter-related infection, including catheter-related colonization (CRCOL) and catheter-related bloodstream infection (CRBSI).

FINDINGS

We included 235 patients with 297 dialysis catheters. The catecholamine group had higher proportions of cardiovascular disease (p = 0.002), shock (p < 0.001), mechanical ventilation (p < 0.001), and antibiotic use (p = 0.013). There was no significant between-group difference in the CRBSI incidence (5.742 vs. 3.143 events/1000 catheter-days; p = 0.205). However, the CRCOL incidence was significantly higher in the catecholamine group than in the control group (6.221 vs. 0.898 events/1000 catheter-days; p = 0.006). The prominent pathogenic bacteria were gram-negative bacteria. After adjusting for confounding factors in multivariate logistic models, catecholamine inotropes (OR: 3.575, 95% CI: 1.422-9.912, p = 0.008) and immunosuppression (OR: 2.980, 95% CI: 1.137-7.812, p = 0.026) were independently associated with a higher risk of catheter-related infections.

DISCUSSION

We observed a similar incidence of catheter-related infection with that in other CRRT patients. Using catecholamine inotropes in those patients increased CRCOL risk, which is consistent with previous in vitro studies. Our findings suggest that catecholamine inotropes is an independent risk factor for catheter-related infections in critically ill patients undergoing CRRT.

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.

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.

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.

Clinical significance of multidrug-resistant Acinetobacter baumannii isolated from central venous catheter tip cultures in patients without concomitant bacteremia

BACKGROUND

The purpose of this study was to examine the clinical implications of a positive central venous catheter (CVC) tip culture with multidrug-resistant Acinetobacter baumannii (MRAB) in patients without concurrent bacteremia.

METHODS

This retrospective, multicenter study was conducted in 9 teaching hospitals in the Republic of Korea from May 2008 to April 2012. Study subjects included adult patients (aged ≥ 18 y) who yielded an MRAB-positive CVC tip culture without concurrent MRAB bacteremia. All patients were observed for the development of subsequent MRAB bacteremia for 6 months after CVC removal. Multivariable Firth logistic regression analysis was performed to determine predictors independently associated with subsequent MRAB bacteremia.

RESULTS

During the study period, subsequent MRAB bacteremia was observed in 18.8% of patients (21/112). Of the 112 patients, 23 (20.5%) did not show systemic inflammatory response syndrome (SIRS). None of the 23 patients without SIRS presented with subsequent MRAB bacteremia. Multivariable logistic regression analysis showed that prior administration of carbapenems (odds ratio (OR) 7.04, 95% confidence interval (CI) 1.43-34.77) or corticosteroids (OR 6.67, 95% CI 1.19-37.44), and C-reactive protein ≥ 40 mg/l (OR 18.11, 95% CI 2.22-148.07) were positive predictive factors. Prior acquisition of MRAB at a site other than the catheter (OR 0.10, 95% CI 0.03-0.39) was a negative predictive factor for developing MRAB bacteremia.

CONCLUSIONS

Our results suggest that patients with a CVC tip colonized with MRAB should be closely monitored for signs and symptoms of subsequent MRAB bacteremia.