Predictors of catheter-related gram-negative bacilli bacteraemia among cancer patients

Evaluation of the microbiological efficacy of cleaning agents for tracheostomy inner cannulas

PURPOSE

Biofilms are a significant cause of morbidity in patients with indwelling medical devices. Biofilms pose a potential risk with reusable inner cannulas by increasing the risk of infections. Effective decontamination is thus vital in decreasing bioburden. The current guidelines for cleaning inner cannulas are varied, with multiple techniques being recommended, which are not supported by strong evidence. This randomized, controlled, cross-over study attempted to enumerate the bacterial count of inner cannulas used in tracheostomy patients (n = 60) pre-and post-decontamination with detergent (A) or sterile water (B).

MATERIALS AND METHODS

The patients were randomly allocated to sequence A > B or B > A in 1:1 fashion. The saline flushing of the inner cannulas was plated on trypticase soy agar with 5 % sheep blood to enumerate the bacterial count.

RESULTS

The mean ratio [Log (CFU)post/Log (CFU)pre]A/[Log (CFU)post/Log (CFU)pre]B based on 53 samples was 0.918 ± 0.470, two-sided 90 % confidence interval (CI) 0.812, 1.024. The equivalence criterion was met as the mean ratio after cleaning fell within the equivalence region of 0.8 and 1.25.

CONCLUSION

This study demonstrated the microbiological efficacy of both detergent and sterile water in the decontamination of inner cannulas, and that sterile water was not less effective than detergent in reducing the bacterial load for safe re-use of inner cannulas. This has the potential to promote cost savings for patients with tracheostomy, both in the hospital and the community. The study findings may also be relevant in formulating tracheostomy care policies.

LEVEL OF EVIDENCE: 1

Central venous catheter-related infections in hematology and oncology: 2020 updated guidelines on diagnosis, management, and prevention by the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO)

Cancer patients frequently require central venous catheters for therapy and parenteral nutrition and are at high risk of central venous catheter-related infections (CRIs). Moreover, CRIs prolong hospitalization, cause an excess in resource utilization and treatment cost, often delay anti-cancer treatment, and are associated with a significant increase in mortality in cancer patients. We therefore summoned a panel of experts by the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO) and updated our previous guideline on CRIs in cancer patients. After conducting systematic literature searches on PubMed, Medline, and Cochrane databases, video- and meeting-based consensus discussions were held. In the presented guideline, we summarize recommendations on definition, diagnosis, management, and prevention of CRIs in cancer patients including the grading of strength of recommendations and the respective levels of evidence. This guideline supports clinicians and researchers alike in the evidence-based decision-making in the management of CRIs in cancer patients.

Infection of totally implantable venous access devices: A review of the literature

Totally implantable venous access devices, or ports, are essential in the therapeutic management of patients who require long-term intermittent intravenous therapy. Totally implantable venous access devices guarantee safe infusion of chemotherapy, blood transfusion, parenteral nutrition, as well as repeated blood samples. Minimizing the need for frequent vascular access, totally implantable venous access devices also improve the patient's quality of life. Nonetheless, totally implantable venous access devices are not free from complications. Among those, infection is the most relevant, affecting patients' morbidity and mortality-both in the hospital or outpatient setting-and increasing healthcare costs. Knowledge of pathogenesis and risk factors of totally implantable venous access device-related infections is crucial to prevent this condition by adopting proper insertion bundles and maintenance bundles based on the best available evidence. Early diagnosis and prompt treatment of infection are of paramount importance. As a totally implantable venous access device-related infection occurs, device removal or a conservative approach should be chosen in treating this complication. For both prevention and therapy, antimicrobial lock is a major matter of controversy and a promising field for future clinical studies. This article reviews current evidences in terms of epidemiology, pathogenesis and risk factors, diagnosis, prevention, and treatment of totally implantable venous access device-related infections.

The growing threat of multidrug-resistant Gram-negative infections in patients with hematologic malignancies

Prolonged neutropenia and chemotherapy-induced mucositis render patients with hematologic malignancies highly vulnerable to Gram-negative bacteremia. Unfortunately, multidrug-resistant (MDR) Gram-negative bacteria are increasingly encountered globally, and current guidelines for empirical antibiotic coverage in these patients may not adequately treat these bacteria. This expansion of resistance, coupled with traditional culturing techniques requiring 2-4 days for bacterial identification and antimicrobial susceptibility results, have grave implications for these immunocompromised hosts. This review characterizes the epidemiology, risk factors, resistance mechanisms, recommended treatments, and outcomes of the MDR Gram-negative bacteria that commonly cause infections in patients with hematologic malignancies. We also examine the infection prevention strategies in hematology patients, such as infection control practices, antimicrobial stewardship, and targeted decolonization. Finally, we assess the strategies to improve outcomes of the infected patients, including gastrointestinal screening to guide empirical antibiotic therapy, new rapid diagnostic tools for expeditious identification of MDR pathogens, and use of two new antimicrobial agents, ceftolozane/tazobactam and ceftazidime/avibactam.

Antibiotic-resistant gram-negative bacterial infections in patients with cancer

Patients with cancer are at high risk for infections caused by antibiotic resistant gram-negative bacteria. In this review, we summarize trends among the major pathogens and clinical syndromes associated with antibiotic resistant gram-negative bacterial infection in patients with malignancy, with special attention to carbapenem and expanded-spectrum β-lactam resistance in Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia--all major threats to our cancer patients. Optimal therapy for these antibiotic-resistant pathogens still remains to be determined.

Advances in prevention and management of central line-associated bloodstream infections in patients with cancer

Central lines, which are essential for treating cancer, are associated with at least 400,000 episodes of bloodstream infection in patients with cancer every year in the United States. Effective novel interventions for preventing and managing these infections include antimicrobial-coated catheters and antimicrobial lock solutions.

Prevention of transmission of multidrug-resistant organisms during catheter exchange using antimicrobial catheters

Exchanging a central venous catheter (CVC) over a guide wire for a fresh uncoated CVC in the presence of bacteremia can result in cross-infection of the newly exchanged CVC. A recent retrospective clinical study showed that exchanging a catheter over a guide wire in the presence of bacteremia using an antimicrobial minocycline-rifampin (M/R) catheter may improve outcomes. To expand on this, we developed an in vitro cross-contamination model of exchange to evaluate the efficacy of different antimicrobial CVCs in preventing cross-contamination of multidrug-resistant organisms during exchange. Uncoated CVCs were allowed to form biofilm by methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. After 24 h, the biofilm-colonized CVCs were placed in a glass tube containing bovine calf serum plus Mueller-Hinton broth, and each catheter was exchanged over a guide wire for a fresh uncoated or an M/R-, chlorhexidine-silver sulfadiazine (CHX/SS)-, or chlorhexidine-M/R (CHX-M/R)-coated CVC. Cross-contamination of exchanged catheters was enumerated by sonication and quantitative plating methods. The exchange of M/R CVCs completely prevented cross-contamination by MRSA biofilms compared to control exchanged CVCs (P<0.0001). Exchange with CHX/SS CVCs reduced but did not completely prevent cross-contamination by MRSA (P=0.005). Exchange with CHX-M/R CVCs completely prevented cross-contamination by MRSA, P. aeruginosa, and C. albicans biofilms (P<0.0001). Furthermore, CHX-M/R CVCs were superior to M/R CVCs against P. aeruginosa and C. albicans (P=0.003) and were superior to CHX/SS CVCs against MRSA and P. aeruginosa (P=0.01). In conclusion, exchange with the novel CHX-M/R CVC was the only exchange effective in completely and concurrently preventing cross-contamination from bacteria and Candida.

Risk factors influencing mortality related to Stenotrophomonas maltophilia infection in hematology-oncology patients

Stenotrophomonas maltophilia infection is of concern in patients with cancer. Antibiotics active against S. maltophilia are rarely used in the treatment of febrile neutropenia, making it important to identify the factors influencing mortality in cancer patients with S. maltophilia infection. The objective of this study was to analyze the clinical characteristics and outcomes of cancer and hemopathic patients with S. maltophilia infection and assess the factors influencing the mortality. The microbiology laboratory records of Erciyes University, Faculty of Medicine Hospital were reviewed to retrospectively identify patients with S. maltophilia infection between January 2007 and June 2011. A total of 38 patients (25 male, 13 female) were eligible for the study. The median age of the patients was 53 years. The underlying disease was hematological malignancy and disorders in 76.3 % (29 cases), solid tumors in 15.8 % (six cases), aplastic anemia in 7.9 % (three cases), while 18.4 % (seven cases) were hematopoietic stem cell transplantation (HSCT) recipients. An indwelling central venous catheter was used in 32 cases (84.2 %). Twenty-seven patients (71.1 %) were neutropenic at the onset of infection. Nine patients (23.7 %) were receiving corticosteroid therapy. The overall 14-day mortality rate was 50 %. Three of the patients received empirical antibacterial treatment, and three HSCT recipients received trimethoprim-sulfamethoxazole prophylaxis, which is active against S. maltophilia. Severe sepsis (OR 13.24, 95 % confidence interval (CI) 1.62-108.57) and the duration of the treatment (OR 0.73, 95 % CI 0.60-0.90) were related to death based on logistic regression analysis findings. In immunocompromised hematology-oncology patients with severe sepsis, S. maltophilia should be considered as a possible cause of infection, and should be given effective empirical antibiotic treatment immediately; the antimicrobial spectrum may be narrowed according to results of antibiotic susceptibility test.

Distribution of pathogens in central line-associated bloodstream infections among patients with and without neutropenia following chemotherapy: evidence for a proposed modification to the current surveillance definition

OBJECTIVE

Many bloodstream infections (BSIs) occurring in patients with febrile neutropenia following cytotoxic chemotherapy are due to translocation of intestinal microbiota. However, these infections meet the National Healthcare Safety Network (NHSN) definition of central line-associated BSIs (CLABSIs). We sought to determine the differences in the microbiology of NHSN-defined CLABSIs in patients with and without neutropenia and, using these data, to propose a modification of the CLABSI definition.

DESIGN

Retrospective review.

SETTING

Two large university hospitals over 18 months.

METHODS

All hospital-acquired BSIs occurring in patients with central venous catheters in place were classified using the NHSN CLABSI definition. Patients with postchemotherapy neutropenia (500 neutrophils/mm(3) or lower) at the time of blood culture were considered neutropenic. Pathogens overrepresented in the neutropenic group were identified to inform development of a modified CLABSI definition.

RESULTS

Organisms that were more commonly observed in the neutropenic group compared with the nonneutropenic group included Escherichia coli (22.7% vs 2.5%; P < .001) but not other Enterobacteriaceae, Enterococcus faecium (18.2% vs 6.1%; P = .002), and streptococci (18.2% vs 0%; P < .001). Application of a modified CLABSI definition (removing BSI with enterococci, streptococci, or E. coli) excluded 33 of 66 neutropenic CLABSIs and decreased the CLABSI rate in one study hospital with large transplant and oncology populations from 2.12 to 1.79 cases per 1,000 line-days.

CONCLUSIONS

Common gastrointestinal organisms were more common in the neutropenia group, suggesting that many BSIs meeting the NHSN criteria for CLABSI in the setting of neutropenia may represent translocation of gut organisms. These findings support modification of the NHSN CLABSI definition.