Bacterial Contamination Of Blood Products Research Articles

Knowledge, attitude and practice survey of bacterial contamination of blood for transfusion in the Democratic Republic of the Congo.

We assessed healthcare worker's knowledge-attitude-practice regarding bacterial contamination of blood products in the Democratic Republic of the Congo. In three hospitals and the National Blood Transfusion Center (NBTC), two multiple-choice surveys were completed on a tablet computer: one each, for blood bank (31 questions) and for clinical ward staff (20 questions). A score was calculated for 11 overlapping knowledge questions. Among 247 participants (blood bank No.=62, ward No.=185), median (range) knowledge score was 10 (2-19) on a maximum of 20, with blood bank staff (12/20) scoring higher than clinical ward staff (9/20) (p<0.0001). Half (50.2%) of 247 participants recalled previous training in transfusion medicine. Participants had limited understanding of and compliance with NBTC-recommended preventive measures: incorrect assumption that wearing gloves prevents bacterial contamination (83.8%) and that blood banks test donor blood for bacteria (59.9%). Half (50.0%) of blood bank staff did not acknowledge the NBTC-recommended antisepsis procedure, 62.1% did not apply the appropriate number of antisepsis steps, and 32.3% saw no harm in touching the venipuncture site after antisepsis. Presence of bacteria on healthy skin (62.3%) and blood bank fomites (examination gloves: 30.8%, soap: 62.8%) was underestimated. Although 92.4% of clinical ward staff said to easily recognize transfusion reactions, only 15.7% recognized septic reactions and post-transfusion antibiotic treatment practices were not consistent. Challenges reported by blood bank staff and particular for low-resource settings were: frequent power cuts (98.4%), transport of blood products by patient attendants (41.1%), without cooling elements (64.4%), and reuse of finished antiseptic/disinfectant containers (75.4%). The present study points to gaps in knowledge, attitudes, practices along sampling, cold chain and transfusion which can feed customized training and monitoring.

Verification of a method using magnetic bead enrichment and nucleic acid extraction to improve the molecular detection of bacterial contamination in blood components.

Bacterial contamination of blood products poses a significant risk in transfusion medicine. Platelets are particularly vulnerable to bacterial growth because they must be stored at room temperature with constant agitation for >5 days. The limitations of bacterial detection using conventional methods, such as blood cultures and lateral flow assays, include the long detection times, low sensitivity, and the requirement for substantial volumes of blood components. To address these limitations, we assessed the performance of a bacterial enrichment technique using antibiotic-conjugated magnetic nanobeads (AcMNBs) and real-time PCR for the detection of bacterial contamination in plasma. AcMNBs successfully captured >80% of four bacterial strains, including Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Klebsiella pneumoniae, in both plasma and phosphate-buffered saline. After 24-h incubation with bacterial enrichment, S. aureus and B. cereus were each detected at 101 CFU/mL in all trials (5/5), E. coli at 101 CFU/mL in 1/5 trials, and K. pneumoniae at 10² CFU/mL in 4/5 trials. Additionally, without incubation, the improvement was also achieved in samples with bacterial enrichment, S. aureus at 10² CFU/mL and B. cereus at 101 CFU/mL in 1/5 trials each, E. coli at 10³ CFU/mL in 3/5 trials, and K. pneumoniae at 10¹ CFU/mL in 2/5 trials. Overall, the findings from this study strongly support the superiority of bacterial enrichment in detecting low-level bacterial contamination in plasma when employing AcMNBs and PCR.IMPORTANCEThe study presents a breakthrough approach to detect bacterial contamination in plasma, a critical concern in transfusion medicine. Traditional methods, such as blood cultures and lateral flow assays, are hampered by slow detection times, low sensitivity, and the need for large blood sample volumes. Our research introduces a novel technique using antibiotic-conjugated magnetic nanobeads combined with real-time PCR, enhancing the detection of bacteria in blood products, especially platelets. This method has shown exceptional efficiency in identifying even low levels of four different species of bacteria in plasma. The ability to detect bacterial contamination rapidly and accurately is vital for ensuring the safety of blood transfusions and can significantly reduce the risk of infections transmitted through blood products. This advancement is a pivotal step in improving patient outcomes and elevating the standards of care in transfusion medicine.

Growth and Distribution of Bacteria in Contaminated Whole Blood and Derived Blood Components

Introduction: Bacterial contamination of blood products presumably occurs mainly during blood collection, starting from low initial concentrations of 10–100 colony-forming units (CFUs) per bag. As little is known about bacterial growth behavior and distribution in stored whole blood (WB) and WB-derived blood products, this study aims to provide data on this subject. Methods: WB units were inoculated with transfusion-relevant bacterial species (Acinetobacter baumannii, Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Pseudomonas fluorescens, Serratia marcescens, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus dysgalactiae, Streptococcus pyogenes, Yersinia enterocolitica; n = 12 for each species), stored for 22–24 h at room temperature, and then centrifuged for separation into plasma, red blood cells (RBCs), and buffy coats (BCs). The latter were pooled with 3 random donor BCs and one unit of PAS-E each to yield plasma-reduced platelet concentrates (PCs). Samples for bacterial colony counting were collected after WB storage and immediately after blood component production. Sterility testing in PCs (n = 12 for each species) was performed by bacterial culture after 7 days of storage. Results: Bacterial growth in WB varied remarkably between donations and species. Streptococcus species produced the highest titers in WB, whereas Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas fluorescens did not multiply. Centrifugation resulted in preferential accumulation of bacteria in BCs, with titers of up to 3.5 × 103 CFU/mL in BCs and up to ≤0.9 × 103 CFU/mL in BC-derived PCs. Overall, 72/144 PCs (50%) tested positive for bacteria after storage. Sterility test results were species-dependent, ranging from 12 of 12 PCs tested positive for Streptococcus pyogenes to 1 of 12 PCs positive for Escherichia coli. Bacterial contamination of RBC and plasma units was much less common and was associated with higher initial bacterial counts in the parent WB units. Conclusions: Bacterial growth in WB is species-dependent and varies greatly between donations. Preferential accumulation of bacteria in BCs during manufacturing is a critical determinant of the contamination risk of BC-derived pooled PCs.

Bacterial Contamination of Blood Products Stored at Room Temperature on Agitator in Lagos State, Nigeria

Abstract BACKGROUND: The relevance of some plasma-based medicinal products, especially platelet concentrates in modern medical care, is confirmed by their inclusion in the World Health Organization Essential Medicines. Therefore, this study characterized bacterial contamination in blood donor’s platelet concentrates in Lagos State. METHODS: A total number of 10 units of screened blood were collected and platelet concentrates were serially sampled following an aseptic procedure and stored for a period of 8 days (day 1 to day 8). The samples were incubated at 37°C on a daily basis for 7 days in brain–heart infusion growth medium and thioglycolate broth, respectively. The identities of the isolated organisms were determined by following standard microbiological techniques. The resistance pattern of isolates to selected antimicrobial agents was also determined by disc diffusion method. RESULTS: The results obtained showed that the overall prevalence of bacterial contamination in platelet concentrates stored at room temperature was 20% (2/10), with the growth on the 1st day of culture. The pattern of the bacterial isolates was Staphylococcus aureus – 10% (1/10) and Staphylococcus epidermidis – 10% (1/10) from 10 platelet concentrates with agitation for 8 days with no evidence of co-bacterial contamination. The resistance pattern of the bacterial isolates to different selected antibiotics ranged from 50% to 100%. There was no significant difference in P value obtained in the comparative analysis of the proportions of S. aureus and S. epidermidis in platelet concentrates (P = 1.000; P &gt; 0.05). The findings of this study also confirmed the presence of multidrug-resistant Gram-positive bacteria in the blood component for transfusion studied in Lagos; the organisms isolated were S. aureus and S. epidermidis. The resistance pattern of the bacteria to the antibiotics ranged from 50% to 100%. CONCLUSION: This work revealed evidence of bacterial contamination in platelet concentrates prepared for transfusion with an overall bacterial contamination of 20% (S. aureus – 10%; S. epidermidis – 10%) with no evidence of co-bacterial contamination but with evidence of S. aureus and S. epidermidis multidrug resistance, hence the need for proper storage and screening of platelet concentrates for bacterial contamination before transfusion to avoid platelet aggregation that may lead to fatal complications in the recipient.

Residual Component Culture: Application of Standardized Transfusion Reaction Culture Criteria to Reduce Culture Rates

Abstract Blood products are often cultured as part of a transfusion reaction (TRXN) workup in order to “not miss” a septic TRXN. These cultures are vulnerable to secondary contamination and are often challenging to interpret due to the lack of a corresponding patient blood culture. Although bacterial contamination of blood products remains a leading cause of transfusion related fatalities, the actual prevalence of primary contamination of blood components is quite low, leading to a low positive predictive value (PPV) for component culture. Given recently mandated mitigation strategies to reduce bacterial contamination of platelets, the PPV of component culture is likely to further decline, making appropriate selection criteria for culture even more critical to conserve laboratory resources and maximize clinical utility. At our institution the decision to culture is at the discretion of the pathology resident and/or transfusion medicine physician. We sought to review our current culture rates and determine if applying standardized indications for component culture could reduce culture rates without impacting diagnostic utility. Clinical symptoms and vital signs were reviewed for the 24-hour period after the reaction for all TRXNs reported from July 2021 to June 2022. Of the 105 reactions reported during the study timeframe, 39 (37%) were cultured, with one positive culture involving a platelet unit. This was deemed a true septic reaction given concordant cultures in the patient. Modified forms of the AABB and BEST culture criteria were then applied to the reported reactions. Modifications were made to provide specific definitions for tachycardia (heart rate &amp;gt; 100bpm and at least 15% increase) and hypotension (SBP &amp;lt; 80mmhg and at least a 30mmHg decrease). Application of the AABB criteria reduces the number of cultures to 22 (21% of reactions) whereas the BEST criteria increases the number of cultures to 51 (49% of reactions). Both criteria captured the true positive septic reaction. Neither criteria were completely concordant with our current practice. Of the 39 reactions selected for culture by our institution, 26 (67%) did not meet AABB criteria and 11 (28%) did not met BEST criteria; 9 and 22 different reactions would have been cultured based on AABB and BEST criteria respectively. Although we are not able to confirm if culturing of the discrepant units would have yielded additional positive cultures, retrospective chart review did not reveal any additional cases of clinically significant sepsis. The modified AABB criteria decreased the culture rate by 56% while still capturing the true positive septic TRXN suggesting that it would be the best option to reduce the cost/burden of culturing products without reducing diagnostic accuracy. Both published criteria do not take into consideration duration of symptoms and clinical interventions, thus clinical judgement remains critical to the decision to culture.

Is your blood bag safe for transfusion? Bacterial screening of donor blood and its components: An essential infection control tool for safe transfusion practice

Introduction: Transfusion-associated bacterial sepsis is still a major public health concern that has received little attention. Data on bacterial contamination of blood are scarce, despite rising demand for blood transfusions. Blood bags intended for transfusion should be free of microorganisms. Aim: The aim of the study was to assess the prevalence, identify the microorganisms involved in bacterial contamination of donor blood and blood components and determine blood products most likely to be contaminated, received in microbiology laboratory for sterility testing. Settings and Design: The study was carried out in the department of microbiology in association with the transfusion medicine department of tertiary care hospital in Western Uttar Pradesh from January 2023 to June 2023. Methodology: A total of 87 cellular blood components were tested aerobically for bacterial contamination using the BD BACTEC™ FX 40 automated culture system. For incubation, culture vials that showed positive signals were subcultured onto a set of solid media followed by bacterial identification and antimicrobial susceptibility testing. Results: The overall prevalence rate was 14.9% (whole blood 18.75%, platelets 14.2%, packed cells 13.3% and fresh frozen plasma 10.5%). The contaminants were Aeromonas hydrophila, Sphingomonas paucimobilis, Escherichia coli, Coagulase-negative Staphylococcus spp., Pseudomonas aeruginosa, Delftia acidovorans, and Candida albicans. Discussion: The bacterial contamination in blood products suggests the patient who receives blood products is at risk of developing infection. Implementing proper blood transfusion policies, donor screening and technical staff training will all help to reduce the contamination rate of blood and blood components. Conclusion: Bacterial contamination of blood bags indicates a potential risk of healthcare-associated infection. Microbiological Sterility testing for donor blood bags in blood banks should be used as mandatory infection control Tool for Quality assurance.

Molecular detection of bacterial contamination in plasma using magnetic-based enrichment

Bacterial contamination of blood products is a major problem in transfusion medicine, in terms of both morbidity and mortality. Platelets (PLTs) are stored at room temperature (under constant agitation) for more than 5 days, and bacteria can thus grow significantly from a low level to high titers. However, conventional methods like blood culture and lateral flow assay have disadvantages such as long detection time, low sensitivity, and the need for a large volume of blood components. We used real-time polymerase chain reaction (PCR) assays with antibiotic-conjugated magnetic nanobeads (MNBs) to detect enriched Gram-positive and -negative bacteria. The MNBs were coated with polyethylene glycol (PEG) to prevent aggregation by blood components. Over 80% of all bacteria were captured by the MNBs, and the levels of detection were 101 colony forming unit [CFU]/mL and 102 CFU/mL for Gram-positive and -negative bacteria, respectively. The detection time is < 3 h using only small volumes of blood components. Thus, compared to conventional methods, real-time PCR using MNBs allows for rapid detection with high sensitivity using only a small volume of blood components.

Controlling Infectious Risk in Transfusion: Assessing the Effectiveness of Skin Disinfection in Blood Donors.

Bacterial infectious risk is a major problem in transfusion medicine. The type of micro-organisms isolated during bacterial contamination of blood products indicates that the donor’s skin is its main source. In this context, the primary measures to reduce this risk are: (a) optimal disinfection of the donor’s arm and (b) satellite bag diversion of the initial volume of blood collected. This work aimed to verify the effectiveness of skin disinfection of the blood donor’s venipuncture site. Two methodological approaches were used: (a) qualitative and quantitative microbiological testing of the skin at the collection site, before and post-disinfection; (b) qualitative microbiological testing of the first deviated blood. Pre-disinfection testing showed skin microbial load values between 3 and >200 CFU/plate. More than two-thirds of the isolates were Gram-positive bacteria (77.8%) of which 57.7% were staphylococci. Among Gram-negative bacteria, Pseudomonadaceae, Enterobacteriaceae, and Acinetobacter spp. were isolated from the blood donors (BDs). Post-disinfection, a 100% reduction in microbial load was observed in 84.4% of BDs. Microbiological testing of the first blood diverted sample revealed the presence of microbial flora in 1.9% samples; of the isolates, 83.3% were non-aureus staphylococci. This study highlights the importance of the correct application of skin disinfection procedures in order to ensure blood safety.

The international experience of bacterial screen testing of platelet components with automated microbial detection systems: An update.

In 2014, the bacterial subgroup of the Transfusion-Transmitted Infectious Diseases working party of ISBT published a review on the International Experience of Bacterial Screen Testing of Platelet Components (PCs) with an Automated Microbial Detection System. The purpose of this review, which is focused on publications on or after 2014, is to summarize recent experiences related to bacterial contamination of PCs and the use of an automated culture method to safeguard the blood supply. We first reviewed septic transfusion reactions after PC transfusion as reported in national haemovigilance systems along with a few reports from various countries on bacterial contamination of blood products. Next, we reviewed PC automated culture protocols employed by national blood services in the United Kingdom, Australia, Canada and large blood collection organization and hospital transfusion services in the United States. Then, we acknowledged the limitations of currently available culture methodologies in abating the risks of transfusion-transmitted bacterial infection, through a review of case reports. This review was neither meant to be critical of the literature reviewed nor meant to identify or recommend a best practice. We concluded that significant risk reduction can be achieved by one or a combination of more than one strategy. No one approach is feasible for all institutions worldwide. In selecting strategies, institutions should consider the possible impact on platelet components availability and entertain a risk-based decision-making approach that accounts for operational, logistical and financial factors.

Characterization of the Antibacterial Activity of an SiO2 Nanoparticular Coating to Prevent Bacterial Contamination in Blood Products

Technological innovations and quality control processes within blood supply organizations have significantly improved blood safety for both donors and recipients. Nevertheless, the risk of transfusion-transmitted infection remains non-negligible. Applying a nanoparticular, antibacterial coating at the surface of medical devices is a promising strategy to prevent the spread of infections. In this study, we characterized the antibacterial activity of an SiO2 nanoparticular coating (i.e., the “Medical Antibacterial and Antiadhesive Coating” [MAAC]) applied on relevant polymeric materials (PM) used in the biomedical field. Electron microscopy revealed a smoother surface for the MAAC-treated PM compared to the reference, suggesting antiadhesive properties. The antibacterial activity was tested against selected Gram-positive and Gram-negative bacteria in accordance with ISO 22196. Bacterial growth was significantly reduced for the MAAC-treated PVC, plasticized PVC, polyurethane and silicone (90–99.999%) in which antibacterial activity of ≥1 log reduction was reached for all bacterial strains tested. Cytotoxicity was evaluated following ISO 10993-5 guidelines and L929 cell viability was calculated at ≥90% in the presence of MAAC. This study demonstrates that the MAAC could prevent bacterial contamination as demonstrated by the ISO 22196 tests, while further work needs to be done to improve the coating processability and effectiveness of more complex matrices.

Periodontitis increases risk of viable bacteria in freshly drawn blood donations.

The aim of the study was to determine if periodontitis, which often causes transient bacteraemia, associates with viable bacteria in standard blood donations. This was a cross-sectional study of 60 self-reported medically healthy blood donors aged over 50 years. According to standard procedures, whole blood was separated by fractionation into plasma, buffy-coat, and red blood cell (RBC)-fractions. The buffy-coat was screened for bacterial contamination using BacT/ALERT. Samples from plasma and RBC-fractions were incubated anaerobically and aerobically at 37°C for 7 days on trypticase soy blood agar (TSA). For identification, colony polymerase chain reaction was performed using primers targeting 16S rDNA. From 62% of the donors with periodontitis, bacterial growth was observed on at least 1 out of 4 plates inoculated with plasma or RBCs, whereas only 13% of plates inoculated with plasma or RBCs from periodontally healthy controls yielded bacterial growth (relative risk 6.4, 95% CI: 2.1; 19.5; p=0.0011). None of the donors tested positive for bacterial contamination using BacT/ALERT. Cutibacterium acnes was found in 31% of the donations from donors with periodontitis and in 10% of the donations from periodontally healthy donors. In addition, Staphylococcus species, Bacillus mycoides, Aggregatibacter aphrophilus, and Corynebacterium kroppenstedtii were detected. Periodontitis increased the risk of bacterial contamination of blood products. Contaminating bacteria are often associated with the RBC-fraction. As the BacT/ALERT test is generally performed on platelet products, routine screening fails to detect many occurrences of viable bacteria in the RBC-fraction.

Bacterial contamination of blood products in Africa.

Bacterial contamination of blood components (notably platelets) remains a leading infectious risk to the blood supply. There has been extensive research in high-income countries to characterize the risk of bacterial contamination along with adoption of strategies to mitigate that risk. By contrast, related data in Africa are lacking. An electronic survey was distributed to members of African Society of Blood Transfusion to assess existing or planned measures at African blood centers and hospitals to mitigate bacterial contamination of blood products. A literature review of studies pertaining to related transfusion-associated risk in Africa was conducted to complement the findings. Forty-five responses were received, representing 16 African countries. All respondents were urban, either in blood centers (n = 36) or hospital-based transfusion services (n = 9). Reported measures included skin disinfection (n = 41 [91.1%]); diversion pouches (n = 14 [31.1%]); bacterial culture (n = 9 [20%]); pathogen reduction (PR) (n = 3 [6.7%]); and point-of-release testing (PoRT) (n = 2 [4.4%]). Measures being considered for implementation included: skin disinfection (n = 2 [4.4%]); diversion pouches (n = 2 [4.4%]); bacterial culture n = 14 (31.1%); PR (n = 11 [24.4%]); and PoRT (n = 4 [8.9%]). Of the 38 respondents who reported collection of platelets, 14 (36.8%) and 8 (21.1%) reported using diversion pouches and bacterial culture, respectively. The literature review identified 36 studies on the epidemiology of bacterial contamination and septic transfusion reactions in Africa; rates of contamination ranged from 0% to 17.9%. The findings suggest that prevention of bacterial contamination of blood components and transfusion-associated sepsis in Africa remains neglected. Regional preventive measures have not been widely adopted.

3135 – VISIBLE VIOLET-BLUE LIGHT FOR PATHOGEN REDUCTION OF BLOOD PLASMA: ASSESSMENT OF BROAD SPECTRUM ANTIBACTERIAL EFFICACY AND PRELIMINARY COMPATIBILITY STUDIES

Bacterial contamination of blood products is a major concern in transfusion medicine. Continued efforts to improve blood safety include the use of pathogen reduction technologies (PRTs), which for plasma includes solvent-detergent treatment, or the use of ultraviolet or visible light in combination with photosensitizers. Non-ionizing violet-blue light, in the region of 405nm, has recently demonstrated potential for in situ treatment of ex vivo stored plasma and platelet products, without the need for additional photosensitizers. This study investigates the broad spectrum antibacterial efficacy of 405 nm light for pathogen reduction of plasma samples. Human plasma was seeded with a range of bacteria implicated in transfusion transmitted infections: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Yersinia enterocolitica. The organisms were seeded at 10², 10⁵ and 10⁷ CFU mL⁻¹ densities and exposed to a 405 nm light dose of 360 Jcm⁻² (1-hr at 100 mWcm⁻²). Broad spectrum antibacterial efficacy was observed, with significant bacterial inactivation achieved for all species (P≤0.05). 98.9 – 100 % inactivation was achieved across all seeding densities for all organisms except E. coli, which achieved 95.1 – 100.0 % inactivation. Preliminary protein analysis, conducted using SDS-PAGE, assessed the compatibility of an effective antibacterial dose with plasma proteins. Protein stability tests provide the first evidence for the compatibility of 405 nm light for the decontamination of plasma, with no visible signs of protein degradation detected for doses ≤ 1.8 kJcm⁻². Future studies are required to determine the treatment regime that provides the optimal balance of antibacterial efficacy and product stability.

Different growth kinetics in blood components and genetic analysis of Lactococcus garvieae isolated from platelet concentrates.

In 2014, we experienced the first isolation of Lactococcus garvieae from a platelet concentrate (PC). Thereafter, L. garvieae contamination of PCs occurred in two more cases in Japan. It is rare that bacterial contamination with uncommon strains like this species occurs frequently within a short period. Therefore, we performed a detailed analysis of the characteristics of these strains. Three bacterial strains were identified by biochemical testing and molecular analysis. Genomic diversity was characterized by multilocus sequence typing (MLST). To observe growth kinetics in blood components, PCs were inoculated with the three different strains. All three strains were identified as L. garvieae by molecular analysis. Each strain belonged to a different phylogenetic group according to MLST analysis. In the spiking trial, the three strains demonstrated differences in their final concentrations and changes in appearance of PCs. In this study, all three L. garvieae strains were correctly identified by molecular analysis. Since the three strains were collected in different regions of Japan and belonged to different phylogenetic groups according to MLST analysis, it is suggested that L. garvieae have a wide distribution with diversity in Japan. In PCs, the three L. garvieae strains showed clear differences in growth kinetics and changes in appearance of PCs. These differences may have been the primary determinant of whether PC contamination was detected before transfusion. Moreover, L. garvieae represents an emerging foodborne bacterium that can cause transfusion-transmitted bacteremia. Understanding our cases may help prevent bacterial contamination of blood products.

ANTIBACTERIAL ASSAY OF 2’-HYDROXY-4’,6’,4-TRIMETHOXYCHALCONE AND 4-METHOXYCHALCONE AGAINST GRAM POSITIVE AND GRAM NEGATIVE BACTERIA

Blood transfusion is currently one of the most important health care treatments. Unfortunately, the prevalence of transfusion reactions caused by the use of blood products is still quite high although blood products have been tested in terms of infectious diseases using 4 parameters, namely hepatitis B, hepatitis C, HIV and syphilis. The results of the analysis of blood products produced by UTD (Blood Transfusion Unit) Surabaya showed bacterial contamination of blood products, starting from normal skin flora to pathogens. Bacterial contamination is also believed to be one of the causes of transfusion reactions. Therefore, it is necessary to make efforts to prevent bacterial contamination of blood products. One of the efforts is to find chemical compounds that have good antibacterial activity. In this study, the antibacterial activity of 2ˈ-hydroxy-4ˈ,6ˈ,4-trimethoxychalcone and 4-methoxychalcone was tested against gram positive and gram negative bacteria. The test method was agar diffusion at various concentrations of chalcone, namely 0.625; 1.25; 2.5 and 5.0%. The results showed that both chalcones had good antibacterial activity against gram-positive and gram-negative bacteria.

Effect of donor arm washing on microbial growth at phlebotomy site in first time blood donors

Background: Microbes at the phlebotomy site are the important source of bacterial contamination of blood products. Various methods to reduce their load at phlebotomy site have been tried and have always being improvised upon. Few of the blood centres have adopted a policy of making the donors wash their arms with soap and water before disinfection for phlebotomy. However the utility of this policy has not been studied. Aim: The aim was to study if washing the phlebotomy site with soap and water before blood donation would make an impact or change the microbiota at the site. Materials and methods: The study included 200 whole-blood donors who were randomly chosen and after obtaining an informed consent were included in the study. The donors were alternately allocated into donation arm washing (n=100) or non washing (100) group. The swabs were taken from the phlebotomy site from both the groups and cultured for microbial growth. The results were compared to see for difference between the groups. The statistical analysis was done using IBM SPSS Statistics Desktop Software version 22.0. Results: Multiple organisms were isolated in only three of the 40 donors in the arm washed group compared to 24 of the 50 donors evaluated in the control arm and this difference was statistically significant (p&lt;0.01). Conclusion: This simple add on step of washing the donor arm before donation reduced the microbial floral load at the phlebotomy site.

Surface modification of platelet concentrate bags to reduce biofilm formation and transfusion sepsis

Bacterial contamination of blood products poses a major risk in transfusion medicine, including transfusions involving platelet products. Although testing systems are in place for routine screening of platelet units, the formation of bacterial biofilms in such units may decrease the likelihood that bacteria will be detected. This work determined the surface properties of p-PVC platelet concentrate bags and investigated how these characteristics influenced biofilm formation. Serratia marcescens and Staphylococcus epidermidis, two species commonly implicated in platelet contamination, were used to study biofilm growth. The platelet concentrate bags were physically flattened to determine if reducing the surface roughness altered biofilm formation. The results demonstrated that the flattening process of the platelet bags affected the chemistry of the surface and reduced the surface hydrophobicity. Flattening of the surfaces resulted in a reduction in biofilm formation for both species after 5 days, with S. marcescens demonstrating a greater reduction. However, there was no significant difference between the smooth and flat surfaces following 7 days’ incubation for S. marcescens and no significant differences between any of the surfaces following 7 days’ incubation for S. epidermidis. The results suggest that flattening the p-PVC surfaces may limit potential biofilm formation for the current duration of platelet storage time of 5 days. It is hoped that this work will enhance the understanding of how surface properties influence the development of microbial biofilms in platelet concentrate bags in order to devise a solution to discourage biofilm formation.

Detection of bacterial contamination and DNA quantification in stored blood units in 2 veterinary hospital blood banks.

Blood transfusions in veterinary medicine have become increasingly more common and are now an integral part of lifesaving and advanced treatment in small and large animals. Important risks associated with transfusion of blood products include the transmission of various infectious diseases. Several guidelines suggest what infectious agents to screen for in canine and feline transfusion medicine. However, while the risk of bacterial contamination of blood products during storage and administration has not been documented in veterinary medicine, it has emerged as a cause of morbidity and mortality in human transfusion medicine. Clinical experience shows that the majority of blood component bacterial contaminations are caused by only a few species. Unlike other types of bacteria, psychrotolerant species like Pseudomonas spp. and Serratia spp. can proliferate during the storage of blood units at 4°C from a very low titer at the time of blood collection to a clinically significant level (> 10(5) CFU/mL) causing clinical sepsis resulting from red blood cell concentrate transfusions in human medicine. The purpose of this report was to describe the detection and quantification procedures applied in 4 cases of bacterial contamination of canine and feline blood units, which suggest the need for further investigations to optimize patients' safety in veterinary transfusion medicine.

An Internal Reference Control Duplex Real-Time Polymerase Chain Reaction Assay for Detecting Bacterial Contamination in Blood Products.

Real-time polymerase chain reaction (RT-PCR) enables effective and sensitive screening for infectious risk in the field of blood safety. However, when using RT-PCR to detect bacterial contamination, several intractable points must be considered, one of which is the lack of appropriate quality control. In this study, we developed a simplified RT-PCR assay in which the same primer set and two distinct probes were used to detect both, an internal reference control and the target in a reaction. The copy number of the internal reference control represents the positive detection limit of the assay; therefore, when the threshold-cycle value of the target is less than or equal to that of the internal reference control, the result obtained for the target can be considered to be a true positive. When human gDNA was spiked with Escherichia coli gDNA and the detection limit for the internal reference control was set to five copies, the measured detection limit for E. coli gDNA was two copies. The internal reference control duplex RT-PCR assay showed high efficiency (0.91–1.02), high linearity (R2 > 0.99), and good reproducibility in intra- and inter-assay comparisons. Lastly, when human platelet-rich plasma samples were spiked with E. coli or other bacterial species, all species were detected efficiently, and the results of a two-sample pooled t test showed that the limit of detection for E. coli was 1 cfu/mL. Here, we present a synthetic internal reference control molecule and a new statistical method for improving the reliability of RT-PCR assays when screening for bacterial contamination in blood products.

International survey on definitions and current practices in prevention, diagnosis, management and reporting of transfusion‐transmitted bacterial infections

Background and objectivesTransfusion‐transmitted bacterial infections (TTBI) remain a threat to safe blood transfusion. Currently, there is no consensus on the definition, presentation, management and prevention of TTBI. A common set of criteria would facilitate haemovigilance and benchmarking. An international survey to assess current practices in TTBI was performed as part of efforts in developing an accepted TTBI definition.Material and MethodsAfter a pilot study, the questionnaire was sent via a web‐based survey (www.surveymonkey.com) to members of the International Society of Blood Transfusion (ISBT) Working Parties on Transfusion‐Transmitted Infectious Diseases (bacterial subgroup) and Haemovigilance as well as members of the transfusion community with an interest in transfusion safety.ResultsResults from 58 respondents in 39 countries were available. Twenty‐seven countries had a haemovigilance programme. A TTBI definition was available from 27 respondents (17 countries). The reported clinical presentation and management of TTBI, and procedures to prevent bacterial contamination and screening of blood products varied amongst the respondents. The most frequently cited signs of a TTBI were fever, tachycardia, rigours and hypotension. Common methods to prevent bacterial contamination of blood products included donor health questionnaire, skin disinfection prior to blood collection and use of a diversion pouch. Routine bacterial screening of blood products was performed in 19 countries.ConclusionThis survey highlighted the different practices in TTBI globally and provides a baseline for ongoing endeavours to harmonize TTBI definitions and management.