Inactivation of Clostridium sporogenes and Geobacillus stearothermophilus spores with the use of microwave and steam sterilizers and microwave oven

Introduction. Equipment for sterilization used in medical laboratories must be absolutely effective in eliminating microorganisms and their spores. It often directly influences human health, even life. The aim of the study was to compare the effectiveness of sterilization using the steam sterilizer ASV E, microwave sterilizer EnbioJet ML1, microwave sterilizer for baby bottles and breast pumps AVENT and microwave oven. Materials and methods. Evaluation of the effectiveness of sterilization with the use of selected devices based on pressure-thermal and microwave-thermal methods was conducted, on the basis of elimination of G. stearothermophilus PCM 2104 and C. sporogenes IW 1306 spores. Results. After using the steam sterilizer, 100% inactivation of spores of both species was noted. In the case of EnbioJet ML1 sterilizer, in the test containing 106 CFU × cm–3 G. stearothermophilus spores, 1.63 × 101 CFU × cm–3 survived. The baby bottles sterilizer proved less effective. While the microwave, in the case of tests with the highest spore content, provided their inactivation only at the level of more than 70.0%. The steam sterilizer and EnbioJet ML1 sterilizer were the most effective, whereas the latter ensured a very short time of high temperature effect, which has a favorable impact on the properties of sterilized products, for example compounds decomposing in high temperature. Conclusion. Results of own, as well as other authors’ studies allow to confirm the large potential in the scope of using microwave radiation for the sterilization and disinfection of materials of various sensitivity to temperature.

Effect of commercially available spices and herbs on the survival of Listeria monocytogenes and Salmonella Enteritidis

Background: Currently, natural food preservation methods are explored, one of which includes the useof herbs and spices.Methods: The study assessed the effect of herbs and spices; either opened directly before the test oropened and stored for three months; on the survival of L. monocytogenes and S. Enteritidis bacilli, isolated from meat. Moreover, the microbiological purity of the investigated herbs and spices was evaluated. The research consisted of the analysis of inhibition zone patterns around the wells with spice pulp after the incubation period.Results: Varied influence of herbs and spices on the survival of bacilli was reported, depending on thespecies. The strongest impact against L. monocytogenes, among freshly opened spices, had: granulatedgarlic (38.63 mm), whole cloves (28.87 mm), savoury (22.25 mm), ground cinnamon (22.13 mm), ground ginger (18.75 mm). As for S. Enteritidis, in the group of freshly opened spices, the strongest effect was found for: granulated garlic (37.25 mm), whole cloves (31.50 mm), and ground cinnamon (18.16 mm). It was reported that the storage of open spices caused a decrease in antimicrobial activity against L. monocytogenes, except for cloves, oregano, hot pepper, chilli, sage and turmeric. In the case of S. Enteritidis, the following stored spices were not effective: cinnamon, ground black pepper, sage, oregano, basil, tarragon, marjoram, rosemary, coriander, green mint, hot pepper, chilli, curry.Conclusions: It was confirmed, that herbs and spices, because of its antimicrobial activity can be used,e.g. for food preservation, minimizing the amount of chemical additives applied to the product and extending its shelf-life

The Differences in the Level of Anti-SARS-CoV-2 Antibodies after mRNA Vaccine between Convalescent and Non-Previously Infected People Disappear after the Second Dose—Study in Healthcare Workers Group in Poland

(1) Background: In many infections, antibodies play a crucial role in controlling infection. In COVID-19, the dynamics of the immune system response to SARS-CoV-2 is not fully understood. (2) Methods: The study was conducted on 120 healthcare workers from Dr. Antoni Jurasz University Hospital No. 1 in Bydgoszcz, between June and December 2020. In all participants, IgA and IgG antibody serum concentrations were measured using the semi-quantitative Anti-SARS-CoV-2 ELISA test (Euroimmun). After vaccination, in January and February 2021, antibody levels were examined using the quantitative IgG Anti-SARS-CoV-2 Quantivac ELISA test (Euroimmun). (3) Results: During the whole study period, the SARS-CoV-2 infection was confirmed in 29 (24.2%) participants. In all infected participants, IgA and IgG antibodies were detectable after infection by semi-quantitative serological tests. Levels of antibodies were higher one month after the first dose in the convalescents than in the non-previously infected participants. In this second group, the level of antibodies increased significantly after the second dose of vaccines compared to the first dose. (4) Conclusions: The level of antibodies after the first dose of vaccine in the convalescents’ group is higher than in the SARS-CoV-2 non-infected group, but the differences disappear after the second vaccination

The Assessment of Proteus mirabilis Susceptibility to Ceftazidime and Ciprofloxacin and the Impact of These Antibiotics at Subinhibitory Concentrations on Proteus mirabilis Biofilms

Rods of the Proteus genus are commonly isolated from patients, especially from the urinary tracts of the catheterised patients. The infections associated with biomaterials are crucial therapeutic obstacles, due to the bactericidal resistance of the biofilm. The aim of this study was to assess the susceptibility of P. mirabilis planktonic forms to ciprofloxacin and ceftazidime, the ability to form biofilm, and the impact of chosen sub-MIC concentrations of these antibiotics on biofilm at different stages of its formation. The research included 50 P. mirabilis strains isolated from wounds and the urinary tracts from patients of the University Hospital No. 1 in Bydgoszcz. The assessment of susceptibility to ciprofloxacin and ceftazidime was conducted using micromethods. The impact of sub-MIC concentrations of the chosen antibiotics on the biofilm was measured using the TTC method. The resistance to ciprofloxacin was confirmed for 20 strains (40.0%) while to ceftazidime for 32 (64.0%) of the tested P. mirabilis strains. All of the tested strains formed biofilm: 24.0% weakly, 26.0% moderately, and 50.0% strongly. It was determined that ciprofloxacin and ceftazidime caused eradication of the biofilm. Moreover, the connection between origin of the strains, biofilm maturity level, and resistance to antibiotics was proved

Prevalence of the Genes Associated with Biofilm and Toxins Synthesis amongst the Pseudomonas aeruginosa Clinical Strains

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with an increasing isolation frequency in nosocomial outbreaks. The hypothesis tested was whether carbapenem-resistant P. aeruginosa strains display an altered carriage of the virulence factor genes, depending on the type of carbapenem resistance. The aim of the study was to investigate, by PCR, the frequency of 10 chosen virulence factors genes (phzM, phzS, exoT, exoY, exoU, toxA, exoS, algD, pilA and pilB) and the genotype distribution in 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. P. aeruginosa genes involved in phenazine dyes and exoenzyme T synthesis were noted with the highest frequency (100%). Fimbriae-encoding genes were detected with the lowest incidence: 15.9% and 4.7% for pilin A and B, respectively. The differences observed between the exoS gene prevalence amongst the carbapenemase-positive and the carbapenemase-negative strains and the pilA gene prevalence amongst the strains of different origins were statistically significant. Virulence genes’ prevalence and the genotype distribution vary amongst P. aeruginosa strains resistant to carbapenems, especially in terms of their carbapenemase synthesis ability and the strain origin

Carbapenem-Resistant Pseudomonas aeruginosa Strains-Distribution of the Essential Enzymatic Virulence Factors Genes

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with increasing isolation frequency in nosocomial infections. Herein, we investigated whether antimicrobial-resistant P. aeruginosa strains, e.g., metallo-beta-lactamase (MBL)-producing isolates, may possess a reduced number of virulence genes, resulting from appropriate genome management to adapt to a changing hospital environment. Hospital conditions, such as selective pressure, may lead to the replacement of virulence genes by antimicrobial resistance genes that are crucial to survive under current conditions. The study aimed to compare, using PCR, the frequency of the chosen enzymatic virulence factor genes (alkaline protease-aprA, elastase B-lasB, neuraminidases-nan1 and nan2, and both variants of phospholipase C-plcH and plcN) to MBL distribution among 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. The gene encoding alkaline protease was noted with the highest frequency (100%), while the neuraminidase-1 gene was observed in 37.4% of the examined strains. The difference in lasB and nan1 prevalence amongst the MBL-positive and MBL-negative strains, was statistically significant. Although P. aeruginosa virulence is generally more likely determined by the complex regulation of the virulence gene expression, herein, we found differences in the prevalence of various virulence genes in MBL-producers

Biofilm Formation Reducing Properties of Manuka Honey and Propolis in Proteus mirabilis Rods Isolated from Chronic Wounds

Chronic wound infections are difficult to manage because of the biofilm formation in the wound environment. New measures for eliminating infections are necessary to increase the chance of wound healing. Apitherapy may be the new solution. The aim of this study was to assess the prevalence of wound infection factors and to examine the impact of Manuka honey and ethanol extract of propolis on biofilm formation of Proteus mirabilis isolated from chronic wound infections. According to the findings, the most frequent factors of infection are Staphylococcus aureus (46.1%), Pseudomonas aeruginosa (35.0%), and Proteus mirabilis (10.6%). Minimal inhibitory concentration and minimal bactericidal concentration values were assigned using the microbroth dilution test according to the Clinical and Laboratory Standards Institute. Biofilm of Proteus mirabilis isolates was formed in 96-well polystyrene plates and treated with Manuka honey (concentrations from 1.88% to 30.0%) and ethanol extract of propolis (1.0% to 40.0%). After 24 h, the biofilm viability was expressed by formazan absorbance (λ = 470 nm). Manuka honey reduced the biofilm viability in all, and ethanol extract of propolis in most, of the concentrations tested. Ethanol extract of propolis at the concentrations of 20.0% and 40.0%, reduced biofilm viability stronger than ethanol itself. With these results comes the conclusion that these substances can reduce biofilm formation

The Prevalence of Exoenzyme S Gene in Multidrug-Sensitive and Multidrug-Resistant Pseudomonas aeruginosa Clinical Strains

Pseudomonas aeruginosa rods are one of the most commonly isolated microorganisms from clinical specimens, usually responsible for nosocomial infections. Antibiotic-resistant P. aeruginosa strains may present reduced expression of virulence factors. This fact may be caused by appropriate genome management to adapt to changing conditions of the hospital environment. Virulence factors genes maybe replaced by those crucial to survive, like antimicrobial resistance genes. The aim of this study was to evaluate, using PCR, the occurrence of exoenzyme S-coding gene (exoS) in two distinct groups of P. aeruginosa strains: 83 multidrug-sensitive (MDS) and 65 multidrug-resistant (MDR) isolates. ExoS gene was noted in 72 (48.7%) of the examined strains: 44 (53.0%) MDS and 28 (43.1%) MDR. The observed differ­ences were not statistically significant (p = 0.1505). P. aeruginosa strains virulence is rather determined by the expression regulation of the possessed genes than the difference in genes frequency amongst strains with different antimicrobial susceptibility patterns