Molecular investigation of bacterial communities on the inner and outer surfaces of peripheral venous catheters

Short Peripheral Venous Catheters Contamination and the Dangers of Bloodstream Infection in Portugal: An Analytic Study

Peripheral venous catheters (PVCs) are the most used vascular access devices in the world. However, failure rates remain considerably high, with complications such as PVC-related infections posing significant threats to patients’ well-being. In Portugal, studies evaluating the contamination of these vascular medical devices and characterizing the associated microorganisms are scarce and lack insight into potential virulence factors. To address this gap, we analyzed 110 PVC tips collected in a large tertiary hospital in Portugal. Experiments followed Maki et al.’s semi-quantitative method for microbiological diagnosis. Staphylococcus spp. were subsequently studied for the antimicrobial susceptibility profile by disc diffusion method and based on the cefoxitin phenotype, were further classified into strains resistant to methicillin. Screening for the mecA gene was also done by a polymerase chain reaction and minimum inhibitory concentration (MIC)-vancomycin as determined by E-test, proteolytic and hemolytic activity on skimmed milk 1% plate and blood agar, respectively. The biofilm formation was evaluated on microplate reading through iodonitrotetrazolium chloride 95% (INT). Overall, 30% of PVCs were contaminated, and the most prevalent genus was Staphylococcus spp., 48.8%. This genus presented resistance to penicillin (91%), erythromycin (82%), ciprofloxacin (64%), and cefoxitin (59%). Thus, 59% of strains were considered resistant to methicillin; however, we detected the mecA gene in 82% of the isolates tested. Regarding the virulence factors, 36.4% presented α-hemolysis and 22.7% β-hemolysis, 63.6% presented a positive result for the production of proteases, and 63.6% presented a biofilm formation capacity. Nearly 36.4% were simultaneously resistant to methicillin and showed expression of proteases and/or hemolysins, biofilm formation, and the MIC to vancomycin were greater than 2 µg/mL. Conclusion: PVCs were mainly contaminated with Staphylococcus spp., with high pathogenicity and resistance to antibiotics. The production of virulence factors strengthens the attachment and the permanence to the catheter’s lumen. Quality improvement initiatives are needed to mitigate such results and enhance the quality and safety of the care provided in this field.

Circulating Microbial Cell-Free DNA in Health and Disease

Human blood contains low biomass of circulating microbial cell-free DNA (cfmDNA) that predominantly originates from bacteria. Numerous studies have detected circulating cfmDNA in patients with infectious and non-infectious diseases, and in healthy individuals. Remarkable differences were found in the microbial composition of healthy subjects and patients compared to cohorts with various diseases or even patients with diversified prognoses, implying that these alterations may be associated with disease development. Although the function of circulating cfmDNA needs to be elucidated (whether it acts as a bystander of dysbiosis or a key player in disease development), several studies have demonstrated its potential as a non-invasive biomarker that may improve diagnosis and treatment efficacy. The origin of circulating cfmDNA is still the subject of much deliberation, but studies have identified members of various microbiome niches, including the gut, oral cavity, airways, and skin. Further studies investigating the origin and function of circulating cfmDNA are needed. Moreover, low-biomass microbiome studies are prone to contamination, therefore stringent negative experimental control reactions and decontamination frameworks are advised in order to detect genuine circulating cfmDNA.

Compliance assessment regarding the PVC management on normal wards of a university hospital

Objective

The risk of peripheral venous catheter (PVC) infections in inpatients is often underestimated, even if it is lower than that for central venous catheters. Guidelines for the prevention of PVC-associated infections describe the evidence-based management of PVCs. The aims of this study were the development of standardized methods for compliance assessment regarding PVC management and the evaluation of self-reported knowledge and implementations among healthcare providers regarding PVC care.

Method

We developed a checklist based on the recommendation of the Commission of Hospital Hygiene and Infection Prevention at the Robert Koch Institute (KRINKO) Berlin for the standardized evaluation of PVC management. The following parameters were collected and evaluated: condition of the puncture site, condition of the bandage, presence of an extension set, presence of a plug, and documentation. The checklist was applied in 14 normal wards in 2019. After feedback of the ward staff on the results, it was applied again in 2020 in the same wards. For retrospective data analysis, we used a newly developed PVC-quality index. After the second evaluation in 2020, we carried out an anonymous survey among the healthcare providers.

Results

The evaluation of 627 indwelling PVCs showed a significant increase in compliance related to the presence of an extension set (p=0.049) and documentation (p<0.001) in the 2nd year. The quality index increased in 12 out of 14 wards. The participants of the survey were aware of the in-house standard "Prevention of vascular catheter-associated infections", with a mean score of 4.98 on a Likert scale (1=not aware, 7=completely aware). The main barrier to implementation of the preventive measures was the time factor. Survey participants were more aware of PVC placement than PVC care.

Conclusion

The PVC quality index is a valuable tool for the assessment of compliance regarding PVC management in daily practice. Feedback from the ward staff on the results of compliance assessment improves PVC management, but the outcome is very heterogeneous.

Blood microbiota composition in Iranian pre-diabetic and type 2 diabetic patients

BACKGROUND

Type 2 diabetes as the most prevalent metabolic disorder, is one of the major causes of morbidity and mortality worldwide. Recent studies suggest that body microbiota may play a role in developing metabolic disorders including type 2 diabetes. The objective of the present study was to investigate the blood microbiota composition in Iranian pre-diabetic and type 2 diabetic patients compared to healthy individuals.

METHODS

Blood samples were taken after 12-h fasting from 90 participants, 30 healthy individuals, 30 type 2 diabetes patients and 30 pre-diabetic participants. The buffy coat layer separated by centrifugation at 800 and DNA was extracted using a column-based method. Composition and load of blood microbiota was evaluated by real-time PCR method using genus specific 16S rRNA primers.

RESULTS

The load of Akkermansia, and Faecalibacterium was higher in normal volunteers compared to pre-diabetic and type 2 diabetes group (p< 0.05).The load of Bifidobacterium was higher in normal volunteers compared to type 2 diabetes patients (p= 0.02).In contrast, the load of Lactobacillus and Escherichia coli was higher in pre-diabetics and type 2 diabetes patients compared to normal volunteers (p< 0.05).The load of Bacteroides fragilis was not statistically different between studied groups but it was higher in males compared to female group (p= 0.04). the load of other bacteria was not significantly different between male and female participants.

CONCLUSION

There is difference between microbiota composition in white blood cells of pre-diabetic and type 2 diabetes patients compared to healthy people. Determination of blood microbiota pattern may have a role in diagnosis and preventive of type 2 diabetes in a certain population. For more clarification about correlation between blood microbiota and type 2 diabetes, larger studies with more participants in different ethnical populations is suggested.

Antibacterial plasticizers based on bio-based engineering elastomers for medical PVC: synthesis, characterization and properties

Antibacterial plasticizers for medical PVC have been synthesized by the modification of bio-based engineering elastomers with a quaternary ammonium salt. PVC blended with such plasticizers showed good antibacterial properties and biocompatibility.

Blood Microbiota and Circulating Microbial Metabolites in Diabetes and Cardiovascular Disease

Diabetes and cardiovascular disease (CVD) have evolved as the leading cause of mortality and morbidity worldwide. In addition to traditional risk factors, recent studies have established that the human microbiota, particularly gut bacteria, plays a role in the development of diabetes and CVD. Although the presence of microbes in blood has been known for centuries, mounting evidence in this metagenomic era provides new insights into the role of the blood microbiota in the pathogenesis of non-infectious diseases such as diabetes and CVD. We highlight the origin and physiology of the blood microbiota and circulating microbial metabolites in relation to the etiology and progression of diabetes and CVD. We also discuss translational perspectives targeting the blood microbiota in the diagnosis and treatment of diabetes and CVD.

Skin colonization at peripheral intravenous catheter insertion sites increases the risk of catheter colonization and infection

BACKGROUND

Peripheral intravenous catheters (PIVCs) break the skin barrier, and preinsertion antiseptic disinfection and sterile dressings are used to reduce risk of catheter-related bloodstream infection (CRBSI). In this study, the impact of PIVC skin site colonization on tip colonization and the development of CRBSI was investigated.

METHODS

A total of 137 patients' PIVC skin site swabs and paired PIVC tips were collected at catheter removal, cultured, and bacterial species and clonality were identified.

RESULTS

Of 137 patients, 45 (33%) had colonized skin sites and/or PIVC tips. Of 16 patients with paired colonization of both the skin site and PIVC tips, 11 (69%) were colonized with the same bacterial species. Of these, 77% were clonally related, including 1 identical clone of Pseudomonas aeruginosa in a patient with systemic infection and the same organism identified in blood culture.

CONCLUSIONS

The results demonstrate that opportunistic pathogen colonization at the skin site poses a significant risk for PIVC colonization and CRBSI. Further research is needed to improve current preinsertion antiseptic disinfection of PIVC skin site and the sterile insertion procedure to potentially reduce PIVC colonization and infection risk.

Clinical Features of Bloodstream Infections Associated with Peripheral Versus Central Venous Catheters

Introduction

This study aimed to compare the clinical characteristics and prognoses of central venous catheter-associated bloodstream infections (CVC-BSIs) with peripheral venous catheter-associated BSIs (PVC-BSIs).

Methods

This retrospective observational study was conducted between April 2011 and March 2013 at a teaching hospital in Tokyo, Japan. Adult patients who developed CVC-BSIs and PVC-BSIs more than 2 days after admission were included. Patients with both CVC-BSIs and PVC-BSIs were excluded. Clinical characteristics of patients with CVC-BSIs and PVC-BSIs were obtained from medical records, and 30-day all-cause mortality was measured as the clinical outcome.

Results

We enrolled 124 PVC-BSI cases and 110 CVC-BSI cases. Median age, age-adjusted Charlson score, Sequential Organ Failure Assessment score, sex, and ward type at BSI onset did not differ significantly between the two groups. The median duration of catheter indwelling was significantly shorter in the PVC-BSI group than in the CVC-BSI group. Staphylococcus aureus and Gram-negative bacilli infections were more frequent and coagulase-negative staphylococci (CNS) and Candida spp. infections were less frequent in the PVC-BSI group than in the CVC-BSI group. The prevalence of oxacillin resistance among causative S. aureus and CNS, 30-day all-cause mortality, and appropriateness of empirical and definitive antimicrobial therapies did not differ significantly between the two groups.

Conclusion

The pathogen species distribution varies between PVC-BSIs and CVC-BSIs. However, all-cause mortality does not differ between the two groups. PVCs are not safer than CVCs with respect to BSIs; therefore, it is necessary to use similar precautions relevant to CVC use in order to avoid unnecessary use of PVCs.

Accepted but Unacceptable: Peripheral IV Catheter Failure

Peripheral intravenous (IV) catheter insertion, the most common invasive hospital procedure performed worldwide, is associated with a variety of complications and an unacceptably high overall failure rate of 35% to 50% in even the best of hands. Catheter failure is costly to patients, caregivers, and the health care system. Although advances have been made, analysis of the mechanisms underlying the persistent high rate of peripheral IV failure reveals opportunities for improvement.

Short-term Peripheral Venous Catheter-Related Bloodstream Infections: A Systematic Review

Short-term peripheral venous catheters (PVCs) are commonly used in healthcare settings. To determine the magnitude of bloodstream infections (BSIs) related to their use, PubMed, article bibliographies, and the authors' library were searched for pertinent articles. The incidence of PVC-related BSIs was 0.18% among 85063 PVCs. Short-term PVCs accounted for a mean of 6.3% and 23% of nosocomial BSIs and nosocomial catheter-related BSIs, respectively. Prolonged dwell time and catheter insertion under emergent conditions increased risk of PVC-related bloodstream infection (PVCR-BSI). If approximately 200 million PVCs are successfully inserted into adult patients each year in the United States, there may be many PVCR-BSIs occurring yearly. Clinicians should obtain blood cultures in patients with evidence of PVC infection and systemic symptomatology such as fever, carefully inspect the PVC insertion site in bacteremic or fungemic patients, and remove PVCs associated with localized infection with or without associated BSI.

Non-culture based diagnostics for intravascular catheter related bloodstream infections

INTRODUCTION

intravascular catheter related bloodstream infection (IVC-BSI) is a leading cause of nosocomial infections and associated with significant morbidity and mortality. Early detection and adequate treatment of causative pathogens is critical for a favourable outcome. However, it takes significant time to receive microbiological results due to the current reference diagnostic method's reliance on microbial growth. Areas covered: This review discusses culture and non-culture based techniques for the diagnosis of non IVC-BSI and IVC-BSI, including molecular methods and biomarkers. Different diagnostic strategies are evaluated and the potential of new generation of diagnostic assays highlighted. Expert commentary: The development of additional diagnostic methods has potential to beneficially supplement conventional culture diagnosis, and molecular techniques have particular potential to fulfil this need. They would also contribute significant new knowledge on the bacterial species present on catheters that are generally missed by diagnosis using traditionally culture-dependent methods. Advances in molecular strategies, together with new biomarkers, might lead to the development of faster, more sensitive and cheaper technologies and instruments. This review aims to provide a platform for the further development of IVCBSI diagnostic techniques.

Accepted but unacceptable: peripheral IV catheter failure

Peripheral intravenous (IV) catheter insertion, the most common invasive hospital procedure performed worldwide, is associated with a variety of complications and an unacceptably high overall failure rate of 35% to 50% in even the best of hands. Catheter failure is costly to patients, caregivers, and the health care system. Although advances have been made, analysis of the mechanisms underlying the persistent high rate of peripheral IV failure reveals opportunities for improvement.

Molecular Comparison of Bacterial Communities on Peripheral Intravenous Catheters and Matched Skin Swabs

Skin bacteria at peripheral intravenous catheter (PIVC) insertion sites pose a serious risk of microbial migration and subsequent colonisation of PIVCs, and the development of catheter related bloodstream infections (CRBSIs). Common skin bacteria are often associated with CRBSIs, therefore the bacterial communities at PIVC skin sites are likely to have major implications for PIVC colonisation. This study aimed to determine the bacterial community structures on skin at PIVC insertion sites and to compare the diversity with associated PIVCs. A total of 10 PIVC skin site swabs and matching PIVC tips were collected by a research nurse from 10 hospitalised medical/surgical patients at catheter removal. All swabs and PIVCs underwent traditional culture and high-throughput sequencing. The bacterial communities on PIVC skin swabs and matching PIVCs were diverse and significantly associated (correlation coefficient = 0.7, p<0.001). Methylobacterium spp. was the dominant genus in all PIVC tip samples, but not so for skin swabs. Sixty-one percent of all reads from the PIVC tips and 36% of all reads from the skin swabs belonged to this genus. Staphylococcus spp., (26%), Pseudomonas spp., (10%) and Acinetobacter spp. (10%) were detected from skin swabs but not from PIVC tips. Most skin associated bacteria commonly associated with CRBSIs were observed on skin sites, but not on PIVCs. Diverse bacterial communities were observed at skin sites despite skin decolonization at PIVC insertion. The positive association of skin and PIVC tip communities provides further evidence that skin is a major source of PIVC colonisation via bacterial migration but microbes present may be different to those traditionally identified via culture methods. The results provide new insights into the colonisation of catheters and potential pathogenesis of bacteria associated with CRBSI, and may assist in developing new strategies designed to reduce the risk of CRBSI.

Microbial biofilms associated with intravascular catheter-related bloodstream infections in adult intensive care patients

Catheter-related bloodstream infection (CRBSI) is one of the most serious complications in hospitalised patients, leading to increased hospitalisation, intensive care admissions, extensive antibiotic treatment and mortality. A greater understanding of these bacterial infections is needed to improve the prevention and the management of CRBSIs. We describe here the systematic culture-independent evaluation of intravascular catheter (IVC) bacteriology. Twelve IVCs (6 central venous catheters and 6 arterial catheters) were collected from 6 patients. By using traditional culture methods, 3 patients were diagnosed with catheter colonisation including 1 patient who also had CRBSI, and 3 had no colonisation. From a total of 839,539 high-quality sequence reads from high-throughput sequencing, 8 microbial phyla and 76 diverse microbial genera were detected. All IVCs examined in this study were colonised with complex microbial communities including "non-colonised IVCs," as defined using traditional culture methods. Two main community types were observed: Enterobacteriaceae spp., dominant in patients without colonisation or CRBSI; and Staphylococcus spp., dominant in patients with colonisation and CRBSI. More diverse pathogens and a higher microbial diversity were present in patients with IVC colonisation and CRBSI. Community composition did not appear to be affected by patients' antibiotic treatment or IVC type. Characterisation of these communities is the first step in elucidating roles of these pathogens in disease progression, and to ultimately facilitate the improved prevention, refined diagnosis and management of CRBSI.

Microbial diversity on intravascular catheters from paediatric patients

Microorganisms play important roles in intravascular catheter (IVC)-related infections, which are the most serious complications in children with IVCs, leading to increased hospitalisation, intensive care admissions, extensive antibiotic treatment and mortality. A greater understanding of bacterial communities is needed in order to improve the management of infections. We describe here the systematic culture-independent evaluation of IVC bacteriology in IVC biofilms. Twenty-four IVC samples (six peripherally inserted central catheters, eight central venous catheters and ten arterial catheters) were collected from 24 paediatric patients aged 0 to 14 years old. Barcoded amplicon libraries produced from genes coding 16S rRNA and roll-plate culture methods were used to determine the microbial composition of these samples. From a total of 1,043,406 high-quality sequence reads, eight microbial phyla and 136 diverse microbial genera were detected, separated into 12,224 operational taxonomic units (OTUs). Three phyla (Actinobacteria, Firmicutes and Proteobacteria) predominate the microorganism on the IVC surfaces, with Firmicutes representing nearly half of the OTUs found. Among the Firmicutes, Staphylococcus (15.0% of 16S rRNA reads), Streptococcus (9.6%) and Bacillus (6.1%) were the most common. Community composition did not appear to be affected by patients' age, gender, antibiotic treatment or IVC type. Differences in IVC microbiota were more likely associated with events arising from catheter dwell time, rather than the type of IVC used.

Microbial biofilms on needleless connectors for central venous catheters: comparison of standard and silver-coated devices collected from patients in an acute care hospital

Microorganisms may colonize needleless connectors (NCs) on intravascular catheters, forming biofilms and predisposing patients to catheter-associated infection (CAI). Standard and silver-coated NCs were collected from catheterized intensive care unit patients to characterize biofilm formation using culture-dependent and culture-independent methods and to investigate the associations between NC usage and biofilm characteristics. Viable microorganisms were detected by plate counts from 46% of standard NCs and 59% of silver-coated NCs (P=0.11). There were no significant associations (P>0.05, chi-square test) between catheter type, side of catheter placement, number of catheter lumens, site of catheter placement, or NC placement duration and positive NC findings. There was an association (P=0.04, chi-square test) between infusion type and positive findings for standard NCs. Viable microorganisms exhibiting intracellular esterase activity were detected on >90% of both NC types (P=0.751), suggesting that a large percentage of organisms were not culturable using the conditions provided in this study. Amplification of the 16S rRNA gene from selected NCs provided a substantially larger number of operational taxonomic units per NC than did plate counts (26 to 43 versus 1 to 4 operational taxonomic units/NC, respectively), suggesting that culture-dependent methods may substantially underestimate microbial diversity on NCs. NC bacterial communities were clustered by patient and venous access type and may reflect the composition of the patient's local microbiome but also may contain organisms from the health care environment. NCs provide a portal of entry for a wide diversity of opportunistic pathogens to colonize the catheter lumen, forming a biofilm and increasing the potential for CAI, highlighting the importance of catheter maintenance practices to reduce microbial contamination.