Tryptic Soy Broth Research Articles

Dispersant Effects on Single-Walled Carbon Nanotube Antibacterial Activity.

There is significant interest in understanding whether nanomaterials with outstanding mechanical or electrical properties also possess antibacterial properties. However, assessment of antibacterial activity is a complex problem at the interface of chemistry and microbiology. Results can be affected by many factors including nanomaterial size, surface chemistry, concentration, and the dispersion media. The difficulty of dispersing nanomaterials such as single-walled carbon nanotubes (SWNTs) has resulted in many studies being conducted in the presence of dispersion aides which may themselves contribute to bacterial stress. The recent discovery that a standard microbial growth media, tryptic soy broth (TSB), is an effective SWNT dispersant provides a new opportunity to investigate the potential antibacterial activity of SWNTs using dispersants that range from antibacterial to growth-supporting. The five dispersants chosen for this work were Sodium dodecyl sulfate (SDS), pluronic, lysozyme, DNA, and tryptic soy broth. Staphylococcus aureus and Salmonella enterica were used as the model Gram-positive and Gram-negative bacteria. Activity was measured in terms of colony forming unit (CFU) and optical density measurements. None of the systems exhibited activity against Salmonella. SDS was fatal to Staph. aureus regardless of the presence of SWNTs. The activity of pluronic and lysozyme against Staph. aureus was enhanced by the presence of SWNTs. In contrast, the DNA and TSB dispersions did not have any activity regardless of the presence of SWNTs. These results highlight that the purported antibacterial activity of SWNTs may only be effective against bacteria that are sensitized by the dispersant and suggests the need for additional research on the mechanisms by which SWNT-dispersant interactions can result in antibacterial activity.

ISOLATION AND PURIFICATION OF ANTICANCER PROTEIN EXOTXIN A FROM Pseudomonas aeruginosa

Toxins produced from bacteria constitute promising antitumor agents in treating different cancer types. Exotoxin A from Pseudomonas aeruginosa is the highly toxic virulence component that bind to specific cell receptors. This study aimed to purify Exotoxin A from clinically isolated Pseudomonas aeruginosa. A total of 150 bacterial isolates were taken from clinical samples (burn and wounds) and were screened on selective media and identified as P. aeruginosa using biochemical analysis and molecular test by PCR amplification technique utilizing specific primer 16srRNA. Exotoxin A produced from P. aeruginosa were screened and purified by two steps that include gel filtration and ion-exchange chromatography. In this study, 68 isolates were characterized as P. aeruginosa, furthermore, real-time PCR proved that these isolates revealed 100% specificity, sensitivity and had positive amplified bands with a size of 249bp. The concentration of Exotoxin A extracted from P. aeruginosa using Trypticase soy broth was 18 Mg/ml. The percent of Purification and recovery for Exotoxin A was 21.4 %, 40% respectively. Clinical Isolates of Pseudomonas aeruginosa have the potential to produce Exotoxin A that is responsible for pathogenicity.

Direct Quantitative Immunochemical Analysis of Autoinducer Peptide IV for Diagnosing and Stratifying Staphylococcus aureus Infections.

An immunochemical strategy to detect and quantify AIP-IV, the quorum sensing (QS) signaling molecule produced by Staphylococcus aureusagr type IV, is reported here for the first time. Theoretical calculations and molecular modeling studies have assisted on the design and synthesis of a suitable peptide hapten (AIPIVS), allowing to obtain high avidity and specific antibodies toward this peptide despite its low molecular weight. The ELISA developed achieves an IC50 value of 2.80 ± 0.17 and an LOD of 0.19 ± 0.06 nM in complex media such as 1/2 Tryptic Soy Broth. Recognition of other S. aureus AIPs (I–III) is negligible (cross-reactivity below 0.001%), regardless of the structural similarities. A pilot study with a set of clinical isolates from patients with airways infection or colonization demonstrates the potential of this ELISA to perform biomedical investigations related to the role of QS in pathogenesis and the association between dysfunctional agr or the agr type with unfavorable clinical outcomes. The AIP-IV levels could be quantified in the low nanomolar range in less than 1 h after inoculating agr IV-genotyped isolates in the culture broth, while those genotyped as I–III did not show any immunoreactivity after a 48 h growth, pointing to the possibility to use this technology for phenotyping S. aureus. The research strategy here reported can be extended to the rest of the AIP types of S. aureus, allowing the development of powerful multiplexed chips or point-of-care (PoC) diagnostic devices to unequivocally identify its presence and its agr type on samples from infected patients.

Antibacterial activity of bacteria isolated from earthworm (Pheretima sp.) gut against Salmonella typhi and Staphylococcus aureus: in vitro experiments supported by computational docking

Abstract. Husain DR, Wardhani R, Erviani AE. 2022. Antibacterial activity of bacteria isolated from earthworm (Pheretimasp.) gut against Salmonella typhiand Staphylococcus aureus: in vitro experiments supported by computational docking. Biodiversitas 23: 1125-1131. Bacteria have a diverse ecology niche as the effect of a long evolutionary process. They can live along with other organisms as endosymbiont. Research into endosymbiont bacteria began because of their ability to increase host resistance, especially to pathogens. This study aimed to determine the antimicrobial ability of endosymbiont bacterial isolates of earthworms Pheretimasp., Bacillus brevis, and Bacillus choshinensis that inhabit Pheretimasp. were isolated.The isolates were grown on tryptic soy broth media for 24 hours. The isolates were then purified using tryptic soy agar and biochemically tested to ensure both isolates are endosymbiotic bacteria. Antimicrobial activity was tested using agar diffusion methods in pathogenic bacteria, Staphylococcus aureus, and Salmonella typhi. Amoxicillin and chloramphenicol were used as positive controls. The inhibitory test results showed that incubation for 15 days effectively assessed pathogenic bacteria growth inhibition, marked by the largest inhibition zone (21.32 mm for Salmonella typhi and 16.88 mm for Staphylococcus aureus). They were very effective at inhibiting Salmonella typhiand Staphylococcus aureus growths.Endosymbiotic compounds’ had a potential as antimicrobial. The in silico test supports the inhibitory test, which concluded that endosymbiont isolates can be an antimicrobial characterized by low-binding affinity values (-8,6 on tyrocidine) on molecular docking analysis.

In vitro Assessment of Pseudomonas sp. Strain FCBB-2 for Effective Plant Growth Promotion and Antifungal Activity under Drought Stress

The significance of plant growth-promoting rhizobacteria (PGPR) in plant adaptation to harsh conditions is still unknown. Native bacteria were isolated from rhizospheric soils and tested for growth-promoting qualities as well as antagonistic capabilities against phytopathogenic fungi in this investigation. All the Pseudomonas spp. strains were characterized for in vitro drought tolerance in trypticase soy broth supplemented with different concentrations of polyethylene glycol (PEG6000). Out of nine isolates, only one strain was able to tolerate maximum level of stress (−1.03 MPa) and is further screened for plant growth promoting (PGP) properties under non-stress and drought stress conditions. Strain FCBB-2 isolated from cluster bean plant rhizosphere soil, showed multiple PGP activities such as indole-3-acetic acid (IAA) production, siderophore, hydrogen cyanide (HCN) production and exopolysaccharide (EPS) production and antifungal activity under non-stress and drought stress conditions against various plant fungal pathogens like Fusarium oxysporum, Macrophomina phaseolina, Alternaria alternata, Sclerotium hydrophilium, Pythium aphanidermatum and Rhizoctonia solani. The strain FCBB-2 was identified as Pseudomonas aeruginosa based on morphological and 16S rRNA gene sequence analysis and the sequence was submitted to NCBI GenBank under the accession number KT311003.

Development of Quality Control Ranges for Biocide Susceptibility Testing.

Every laboratory test needs validation by quality controls. For biocide susceptibility testing (BST), neither quality control (QC) strains nor QC ranges applicable to these strains are currently available. As QC strains, four well-defined laboratory reference strains (Staphylococcus aureus ATCC® 6538, Enterococcus hirae ATCC® 10541, Escherichia coli ATCC® 10536 and Pseudomonas aeruginosa ATCC® 15442), which have been used previously for biocide efficacy testing, were selected. In an interlaboratory trial with eleven participating laboratories, BST QC ranges should be developed for the aforementioned four strains and the four biocides benzalkonium chloride, chlorhexidine, octenidine and polyhexanide. The performance of three different lots of tryptic soy broth was explored using the broth microdilution method and the data were subsequently evaluated using the RangeFinder software. As a result, QC ranges were defined for all reference strain–biocide combinations, except for P. aeruginosa ATCC® 15442 with the two biocides chlorhexidine and polyhexanide. The development of the latter two QC ranges was not possible, due to the limited solubility of the biocides in the test range required for P. aeruginosa ATCC® 15442. The newly developed QC ranges comprise three to five dilution steps. The establishment of QC ranges will contribute to the validation of BST in the future.

Characterization and antimicrobial susceptibility of biofilm-producing Avian Pathogenic Escherichia coli from broiler chickens and their environment in India.

Avian pathogenic Escherichia coli (APEC) is responsible for colibacillosis in poultry. APEC remains a constant problem for the poultry industry, despite the use of antimicrobials and disinfectants in farms. The endemicity of APEC in poultry farms is associated with its biofilm-forming ability, which is further aggravated by various virulence factors and resistance to multiple drugs that help bacteria to thrive under different environmental conditions. To characterize APEC from affected broiler chickens and their environments, samples (n=114) from dead birds (heart, liver, lungs, and cloacal swab) and surrounding environments such as feeder, drinker, litter, PVC pipe, water tank wall, feed, and water were collected. The collected samples were subjected to microbial isolation using MacConkey Lactose agar (MLA) and Eosin Methylene Blue agar (EMB), which led to the isolation of 62 E. coli isolates. This was confirmed by uspA gene amplification and Vitek 2 Compact. These isolates were characterized using a set of five virulence genes (hlyF, ompT, iroN, iss, iutA), which yielded 47 (75.80%) isolates as APEC and the remaining as non-APEC. Furthermore, all the 62 isolates were subjected to microtiter plate assay for biofilm detection and the result showed that 36 (58.06%) isolates were able to form moderate to strong biofilms in Trypticase soy broth (TSB) at 72h of incubation. Of the 36 biofilm-producing isolates, 30 were APEC. Biofilm-related genes (crl, csgA, fimH, luxS, and papC) were also detected with higher prevalence among APEC isolates. Antimicrobial susceptibility test using Vitek 2 Compact revealed 43 (91.48%) of 47 APEC isolates as multiple drug resistant (MDR) and 8 (17.02%) as ESBL positive. This study reveals that APEC with biofilm formation ability is present in poultry farms. Further studies are needed to understand the role of biofilms in the pathogenesis and antimicrobial resistance of APEC.

Evaluation of the cariogenic potential of a probiotic candidate strain Lactobacillus gasseri YIT 12321

ObjectiveThis study was designed to evaluate the cariogenic potential of Lactobacillus gasseri YIT 12321. DesignL. gasseri YIT 12321 was isolated from the human oral cavity as a probiotic candidate strain. Three types of experimental biofilm formations on bovine enamel specimens were assessed using Streptococcus sobrinus ATCC 33478, L. gasseri YIT 12321, and a co-culture of S. sobrinus and L. gasseri YIT 12321 in vitro. L. gasseri YIT 12321 was analyzed for its ability to utilize seven carbohydrates. L. gasseri YIT 12321 was cultured in tryptic soy broth without dextrose and containing a test carbohydrate at 37 °C for 16 h. ResultsThe decrease in pH in the region under the biofilm produced by L. gasseri YIT 12321 was unusually slow, and the pH was maintained above 5.5 for 16 h. The amount of biofilm and the reduction in enamel hardness were minimal in the L. gasseri YIT 12321 group among the three experimental groups. The amount of co-culture-derived biofilms was less than that of S. sobrinus biofilms. When S. sobrinus was grown using sucrose, the pH decreased to 3.98. In contrast, L. gasseri YIT 12321 cultures maintained the pH above the critical pH for dentin demineralization. ConclusionsL. gasseri YIT 12321 is suggested to have a low cariogenic potential. The application of this strain as a probiotic may contribute to oral safety.

Enhanced inactivation of Salmonella enterica Enteritidis biofilms on the stainless steel surface by proteinase K in the combination with chlorine

This study aimed to determine the enzymatic effect of cellulase, DNase I, and proteinase K on Salmonella enterica Enteritidis biofilms on the stainless steel surface at nutrient availability [tryptic soy broth (TSB) and 20 times diluted TSB (1/20 TSB)] and to evaluate the synergistic effect of proteinase K combined with chlorine (50 ppm for 1 min). The results showed that cellulase and proteinase K degraded S . Enteritidis ME 14 biofilms, regardless of nutrient availability, whereas S . Enteritidis ATCC 13076 biofilms formed in TSB were effectively degraded by all the enzymes tested, but resistant to cellulase and DNase I in 1/20 TSB. Proteinase K or chlorine alone reduced the two S . Enteritidis biofilms formed in TSB by 1.1–1.5 log CFU/cm 2 , while the combined treatment with proteinase K followed by chlorine resulted in 3.8–6.1 log reductions, revealing the synergistic effect. On the contrary, both S . Enteritidis biofilms formed in 1/20 TSB were more resistant to proteinase K treatment followed by chlorine than TSB. Furthermore, microscopic observation using Live/Dead® assay and scanning electron microscopy (SEM) showed that biofilm morphology was greatly altered by the combined treatment, and proteinase K might make it easier for chlorine to penetrate the biofilm matrix. Therefore, these results indicate proteinase K with chlorine-based sanitizer has a potential for effective control of Salmonella biofilms formed on the food contact surface, decreasing the chance of cross-contamination and the risk of salmonellosis. • Cellulase, DNase I, or proteinase K can reduce Salmonella Enteritidis biofilms. • Proteinase K with chlorine synergistically inactivated S. Enteritidis biofilm. • The combined treatment was less effective against biofilm formed in diluted medium. • Biofilm morphology was changed by the combined treatment. • Proteinase K could promote chlorine penetration in biofilm.

Nitrogen source as a modulator of the metabolic activity of Pedobacter lusitanus NL19: a transcriptomic approach.

Secondary metabolites (SMs) are compounds with relevant biological activities. Their production under laboratory conditions, especially in broth, is still challenging. An example is the pedopeptins, which are nonribosomal peptides active against some bacteria listed by the WHO for which new antibiotics are urgently needed. Their biosynthesis is inhibited by high concentrations of peptone from casein (PC) in tryptic soy broth (TSB), and we applied a RNA-seq approach to identify Pedobacter lusitanus NL19 cellular pathways modulated by this condition. Results were validated by qPCR and revealed 261 differentially expressed genes (DEGs), 46.3% of them with a predicted biological function. Specifically, high concentration of PC significantly repressed the de novo biosynthesis of biotin (- 60X) and the production of nonribosomal peptide synthetases (NRPS) of pedopeptins (about - 14X), but no effect was observed on the expression of other NRPS. Transcription of a L-Dap synthesis operon that includes a protein with a σ70-like domain was also reduced (about - 7X). High concentrations of PC led to a significant overexpression of MFS and RND efflux pumps and a ferrous iron uptake system, suggesting the redirection of cell machinery to export compounds such as amino acids, sugars and metal divalent cations, alongside with a slight increase of iron import. KEY POINTS: • Higher concentrations of phosphate sources highly repress many operons • High concentrations of peptone from casein (PC) cause biotin's operon repression • High concentrations of PC downregulate the production of peptides of unknown function.

Development of DNA probes to detect Cronobacter sakazakii based on comparative genomics and its application in food samples

The objective of this study was to develop new primer-probe set to detect Cronobacter sakazakii based on comparative genomics. Among 16 candidates of gene clusters from the results of panX analysis, gene annotated as type 1 fimbrial protein was selected as target of primer and sensitivity/selectivity of designed primer were confirmed with 59 strains. When tryptic soy broth (TSB), phosphate-buffered saline (PBS), Enterobacteriaceae Enrichment (EE), and Escherichia coli DNA were used as interference material, compounds except 50% EE had no significant effect on the detection of C. sakazakii. Moreover, it was verified that the detection efficiency of PCR analysis using designed primer in food samples such as powdered infant formula (PIF), PIF containing Lactobacillus, and milk was not significantly different from conventionally used selective media. These results implicated that designed primer based on comparative genomics can be used effectively for detection of C. sakazakii in various food products.

Impact of antibiotic withdrawal and starvation conditions on plasmid elimination and consequent loss of resistance.

To assess resistance-loss due to plasmid elimination under experimental conditions, including withdrawal of antibiotics and administration of starvation conditions. The experimental study was conducted at the Department of Pathology, King Edward Medical University, Lahore, Pakistan, from July to December 2019. A single sensitive clinical isolate of escherichia coli, showing resistance towards ampicillin was collected and separately sub-cultured in three different culture broths: tryptic soya broth, minimal broth and control broth for a period of one month under standard laboratory conditions. Minimum inhibitory concentrations of the strains were calculated after every seven days to check antibiotic susceptibility. Minimum inhibitory concentrations of the initial escherichia coli strain measured on Day 1 was 6mg/mL and it became sensitive after continual sub-culturing in the absence of antibiotics in 21 days. Due to starvation conditions, the bacterial strain exhibited sensitivity to an even lower antibiotic concentration of 1.5mg/mL on the 28th day. Bacterial growth inhibition zones determined by disc diffusion method using an ampicillin disc of 10µg/mL showed no zone of inhibition. Provision of starvation conditions and withdrawal of antibiotic allowed the escherichia coli strain to exhibit gradual loss of resistance over a period of time.

Assessment of mechanical properties of steel fiber reinforced mortar mixtures containing lightweight aggregates improved by bacteria

The porous nature of lightweight aggregate and its inherent tendency to crack are two main factors related to the penetration of aggressive ions into the concrete matrix in unfavorable environments easily, causing the concrete to deteriorate and reduce its service life. Although the degrading effect of aggressive ions threatens the cement matrix and reinforcement, the inclusion of bacteria and nutrients in cementitious systems leads to CaCO3 precipitation to fill the pores of the aggregates. In this study, Bacillus Subtilis were impregnated into pumice aggregate with 3 different nutrient media, Tryptic Soy Broth, Modify Luria-Bertani, Urea-Calcium-Phosphate. As a result, glucose-based components in nutrient medium increase air entrainment and create a hollow structure in mortar mixture. However, the presence of urea and Ca2+ in nutrient medium increases the CaCO3 precipitation efficiency of bacteria and filling the pores of pumice. Besides, encapsulation is necessary to protect bacteria viability and improve crack healing.

Assessment of bacterial growth in leukoreduced cold-stored whole blood supports overnight hold at room temperature prior to filtration: A pilot study.

Whole blood (WB) transfusion has regained attention to treat trauma patients. We reported no significant changes in in vitro quality through 21 days of cold storage for leukoreduced WB (LCWB) when time to filtration was extended from 8 to 24 h from collection. This study evaluated the impact of extended WB-hold at room temperature (RT) prior to leukoreduction on proliferation of transfusion-relevant bacteria. WB units were spiked with suspensions of Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Listeria monocytogenes prepared in saline solution (SS) or trypticase soy broth (TSB) to a concentration of ~0.2CFU/ml (N= 6). Spiked units were held at RT for 18-24 h before leukoreduction and cold-stored for 21 days. Bacterial growth was determined on days 2, 7, 14 and 21. In vitro quality of WB inoculated with unspiked diluents was assessed. K. pneumoniae and S. pyogenes proliferated in WB prior to leukoreduction reaching concentrations ≤102 CFU/ml. These bacteria, however, did not proliferate during the subsequent cold storage. S. aureus did not survive in WB while L. monocytogenes reached a concentration of ~102 CFU/ml by day 21. LCWB in vitro quality was not affected by SS or TSB. Extended WB-hold prior to leukoreduction allowed proliferation of bacteria able to resist immune clearance, although they did not grow to clinically significant levels. While L. monocytogenes proliferated in LCWB, clinically relevant concentrations were not reached by day 21. These data suggest that transfusing LCWB may not pose a significant bacterial contamination safety risk to transfusion patients.

Comparative evaluation of antibacterial efficacy of Two shape, TruNatomy files against enterococcus faecalis-an invitro study


 Aim: The present study aimed to assess the antibacterial efficiency of Two shape (TS) and TruNatomy files (TRN) files against Enterococcus faecalis.
 Materials and Methodology: Forty human mandibular premolars with single roots were collected and decoronated to standardize the lengths. The specimens were then mounted in acrylic resin and E. faecalis suspension was used to contaminate the specimens and they were incubated for three weeks. All the specimens were divided randomly into four groups. Instrumentation was done using Twoshape files (TS): Group I, TruNatomy files (TRN): Group II & Manual Crown Down technique (CD) using Gatesglidden drills and Hand files: Group III with sterile distilled water as irrrigant.Group IV was served as control group. Microbial samples were collected using paper points without instrumentation of the samples and after instrumentation from intracanal environment, which were diluted and later plated on tryptic soy broth (TSB).
 Results: Significant difference was seen amongst the experimental groups (P<0.05), before and after instrumentation. TS and TRN resulted in more bacterial reduction than CD technique (P<0.05) whereas TS and TRN were almost similar in their efficacy (P>0.05).
 Conclusion: TS and TRN promoted higher bacterial reduction than CD technique, with TS demonstrating the highest antibacterial efficacy.

Isolation of Shewanella putrefaciens GRD 03 from Fish and Explication of Biofilm Adherence Potency on Different Substrates

Foodborne pathogens are the main threat and cause of food poisoning. The majority of food infections have been related to the biofilm formation of foodborne pathogens in the food industry. Shewanella putrefaciens (KX355803, GRD 03), a Gram-negative pathogen isolated from mackerel fish, was identified and recognized as a food spoilage bacterium and a strong biofilm producer. The adhesion or attachment ability of Shewanella putrefaciens was determined on steel, plastic, glass, PVC and wood. NB (Nutrient broth), LB (Luria-Bertani broth), TSB (Tryptic soy broth) and BHI (Brain heart infusion broth) were enriched with glucose and shows optimum for bacterial adhesion. In the microtiter plate method (MTP), the strong attachment was observed at 48 and 72 hours of incubation and significant differences were obtained at p < 0.05. As the incubation period increases, the OD value (Optical density) of samples also increase. Biofilm formation is the major cause cross-contamination, and shows resistance to certain disinfectants, which leads to environmental stress tolerance. This study suggested with optimum biofilm production of isolate from fish by using glucose enriched media on different substrates, also comparing different growth media provide a detailed idea about biofilm-forming ability at different incubation time intervals.

A small-scale ochratoxin A production method for rapid and affordable assay for screening microorganisms for their ability to degrade the mycotoxin

The use of biological agents able to metabolize mycotoxins to non-toxic compounds is a strategy that has received growing interest. However, the high costs of laborious methods for identifying potential candidates are obstacles for new products development. Thereon, our objective was to establish a rapid and affordable bacterial screening assay for ochratoxin A (OTA) biodegradation, based on a small-scale OTA production method to replace the use of mycotoxin standards, aiming to reduce costs. Aspergillus strains were assessed in liquid and solid matrices. A. sclerotioniger CECT 20583 produced the highest OTA levels, 850 μL/L in liquid (day 7) and 5273 μL/kg in solid (day 35). The liquid system was prioritized since the method obtained higher recovery and reproducibility. To verify the applicability, 107 bacterial isolates were screened using microtubes (500 μL of filtered OTA solution + 400 μL of tryptic soy broth (TSB) + 100 μL of inoculum, 24 h incubation). Nineteen isolates showed decontaminating potential, enabling the dismission of more than 80% of initial candidates. In short, the proposed assay requires little time and investment to get information from isolates on their capability of degrading OTA, saving resources for further research stages.

Tailored Media-Fill Test Protocols Inspired by 68Ga Kit-Based Radiopharmaceuticals.

Gallium-68 radiolabeling is an increasingly common activity in radiopharmacy. Single vial cold kits to radiolabel DOTATOC and PSMA-11 with 68Ga were developed, either for manual or automated preparation. Both approaches are very specific and require aseptic compounding skills, raising the need for dedicated training. The aim of this work was to design and implement an integrative media-fill test (MFT) protocol inspired by 68Ga kit-based radiopharmaceuticals for operator qualification, suitable for both manual and automated preparation simulations. Three custom MFT protocols (two manual and one automated simulations) compatible with specific radiopharmacy equipment were designed for operator training. During MFT sessions, the microbiological quality of the working environment was monitored by surface and air sampling. The sensitivity of the tryptic soy broth (TSB) and the influence of the number of punctures performed in each vial on the units positivity were also studied. Four operators were evaluated and carried out in triplicate the three MFTs. None of the 336 incubated units showed turbidity, although 27.8% of surface samples and 11.1% of air samples were positive (1-4 CFU). Over 36 MFT sessions, 15 contaminations of the working area by TSB drops occurred. TSB sensitivity was estimated >3.12 UFC. Units positivity showed a probable relationship with the number of punctures in a vial and, more obviously, with the contamination level of the vial stopper. As a part of a general sterile compounding instruction, these MFT protocols may be useful tools for initial and continuing training of operators carrying out manual and automated 68Ga radiolabeling.

Effect of Breast Silicone Implant Topography on Bacterial Attachment and Growth: An In Vitro Study.

The mechanisms underlying capsular contracture remain unclear. Emerging evidence supports the inflammation hypothesis, according to which bacteria from an adherent biofilm cause chronic inflammation and collagen deposition on the implant and trigger capsular contracture. Our goal was to evaluate the effect of different types of breast implants on the growth of Staphylococcus aureus, S. epidermidis, and Pseudomonas aeruginosa, which are commonly found in biofilms in infection. Bacteria were grown in tryptic soy broth at 37°C for 2, 6, and 24 h and subsequently incubated for 24 h on 12 shell sections of smooth, nano-, and macrotextured breast implants. After incubation, the solutions were ultrasonicated and bacterial numbers were determined by serial dilution. S. aureus were fixed, washed with phosphate-buffered saline, dehydrated in ethanol, and coated with a platinum film to visualize the presence of biofilms by scanning electron microscopy. The numbers of S. aureus and S. epidermidis attached to the smooth and nanotextured surface implants were significantly lower than those on the macrotextured surface for all incubation times, whereas the number of P. aeruginosa was non-significantly lowest on the nanotextured surface after 24h incubation. Biofilms on smooth and nanotextured implant surfaces showed patchy patterns on scanning electron microscopy in contrast to the continuous pattern detected on macrotextured implants. Nanotextured breast implants may limit bacterial growth and thus prevent capsular contracture.

Inactivation efficacy of 405 nm light emitting diodes (LEDs) on Salmonella Enteritidis at different illumination temperatures

Salmonella Enteritidis is the major cause of foodborne salmonellosis affecting human health. The light emitting diodes (LEDs) is a novel approach to inactivate of the foodborne pathogens. The aim of this study was to determine the antibacterial effect of 405 nm LEDs illumination on S. Enteritidis and S. Enteritidis PT4. The irradiance of the 405 nm LEDs was 27.7 mW/cm2. Bacterial cultures suspended in tryptic soy broth were illuminated by 10-watt LEDs at a distance of 4.5 cm for 24 hours at 4 °C, 25 °C and 37 °C. Approximately 7-log reduction in colony forming unit (CFU) counts of both S. Enteritidis and S. Enteritidis PT4 at each temperature were observed following exposure after 7.5 hours to the LEDs, concluding that temperature did not affect the inactivation of the bacteria. The decimal reduction times (D-values) for the serotypes ranged from 55.78 to 67.88 min at 4, 25 and 37 °C after 405 nm LEDs illumination. No significant difference in D-values was observed among both the serotypes and temperatures, except for S. Enteritidis which had lower D-value at 4 °C. The LEDs technology has shown antibacterial efficacy and can be implemented in the food processing for reducing S. Enteritidis.