Biofilm formation of Streptococcus pneumoniae from bronchial alveolar lavage and from nasal swab

Introduction. Infection induced by Streptococcus pneumoniae concerns mainly children, the elderly, and people suffering from chronic diseases. The number of deaths caused by pneumococcus infections is rising worryingly. The ability to create biofilm is the main virulence factor for S. pneumoniae. The aim of this study was to evaluate the ability to form biofilm (using two different dyes) of the bacterial strains isolated from nasal and BAL, and evaluate the relationship between antibiotic sensitivity and production of biofilm. Materials and methods. For the study of S. pneumoniae biofilm formation in 96-well microtitre plates, crystal violet (CV) and tetrazolium dyes — 2,3,5-triphenyl-tetrazolium chloride (TTC) were used. Results. All isolates were able to form some degree of biofilm. The results obtained by the two methods were not significantly correlated when comparing the biofilm mass. The strains produced biofilm mass intensive when the dye was CV — 29 (96.6%) strains of S. pneumoniae strong biofilm production. When the dye was TTC, it was observed that 14 (46.6%) strains of S. pneumoniae formed strong biofilm. Conclusions. There was no significant relationship between the ability of S. pneumoniae to form biofilms and the source of isolates

The effect of blood on the ability of biofilm formation by Listeria monocytogenes strains

Introduction: Listeria monocytogenes strains are widespread in the natural environment and are the etiological factor of listeriosis. Food is the main source of L. monocytogenes. Secondary contamination of food products which results from the formation of biofilm by L. monocytogenes on the surfaces of the processing devices makes an essential problem. Material and methods: We evaluated the ability of biofilm formation in media supplemented with sheep blood (in a volume of 5.0, 10.0, 20.0 and 50.0%) for the reference strain L. monocytogenes ATCC 7644 and strains isolated from the human blood and carrots on the polypropylene surface. Results: The strain isolated from blood most efficiently formed a biofilm with increasing blood sheep’s addition (nutrient broth — 4.87 × 105 CFU × cm-2, blood supplement 50.0% (v/v) — 3.4 × 107 CFU × cm-2).The number of L. monocytogenes recovered from the biofilm for the reference strain and the strain from carrot increased to 20.0% by volume of the blood addition (3.07 × 105 CFU × cm-2 and 4.03 × 105 CFU × cm-2 respectively — nutrient broth; 1.1 × 107 CFU × cm-2 and 9.23 × 106 CFU × cm-2 — blood supplement 20.0% (v/v)). Decrease in the number of cells recovered from the biofilm for the reference strain and the one isolated from carrot has been demonstrated at 50.0% addition of blood into nutrient medium (8.8 × 106 CFU × cm-2 and 7.87 × 106 CFU × cm-2 respectively). Conclusion: The addition of sheep blood to the medium at concentrations up to 20.0% increases the number of cells recovered from the biofilm for all studied L. monocytogenes strains whereas medium with 50.0% blood stimulates the biofilm formation only by the strain isolated from blood

The effect of initial sonication on disinfectant efficacy against Listeria monocytogenes biofilm

Background: Listeria monocytogenes is a Gram-positive, foodborne pathogen. Biofilms formed by thisbacterium are a serious problem in the food industry. Bacteria in biofilms are much more resistant to cleaningand disinfection agents posing a risk of food recontamination. The aim of this study was the assessmentof the influence of initial sonication on disinfectant efficacy, based on QAC, against L. monocytogenesbiofilm on the stainless steel.Methods: The biofilm formed on the stainless steel by the reference strain L. monocytogenes ATCC 19111was sonicated for 1 and 5 minutes (500W/ 20kHz/ 100% amplitude). Then disinfection with quaternaryammonium compounds (0.5% working solution) was applied for 1 and 5 minutes and the number ofbacteria recovered from the biofilm was assessed.Results: It was found that disinfection was more efficient than sonication (p ≤ 0.05). However, the combinationof sonication and disinfection significantly improved biofilm eradication compared to the use ofone of these methods separately (p ≤ 0.05). The greatest reduction of bacteria number was achieved after5 minutes of sonication combined with 5 minutes of disinfection (6.42 log CFU × cm-2), whereas the lowestreduction was observed after 1 minute-sonication (2.03 log CFU × cm-2).Conclusions: Combination of sonication and disinfection based on quaternary ammonium compounds isan effective method allowing biofilm eradication from the food production surfaces

Assessment of drug susceptibility and biofilm formation ability by clinical strains of Listeria monocytogenes

BACKGROUND: Listeria monocytogenes is a cause of listeriosis, dangerous especially for elderly, immunocompromised people and pregnant women. Ability to colonize biotic and abiotic surfaces and form biofilm by these pathogens poses a serious threat for the hospitalized, catheterized patients. METHODS: The study was conducted on 29 L. monocytogenes strains isolated from clinical materials (blood, cerebrospinal fluid, swabs from vagina) and the reference strain L. monocytogenes ATCC 1911. Ability to form biofilm in 96-well plates and drug susceptibility (disk diffusion method) of tested strains was determined. RESULTS: All strains formed biofilm though it’s intensity was correlated with source of isolation. The strong biofilm formed 72.73 % of isolates from cerebrospinal fluid ((A570 0.421 – 1.3), 75.0 % of blood isolates 9 (A570 0.389 – 1.063) and 50.0 % of isolates from vaginal swabs (A570 0.457 – 0.487). The strongest biofilm was formed by strains derived from cerebrospinal fluid whereas isolates from vaginal swabs, which strongly formed a biofilm accounted for 50.0% of the studied population (absorbance 0.457 - 0.487). It was found that 93.1 % (n=27) of strains were susceptible to all drugs tested. Two strains (6.9 %) were resistant to cotrimoxazol and 1 strain (3.45 %) to erythromycin. CONCLUSIONS: Diverse ability to form biofilm by clinical L. monocytogenes strains is an important aspect in prophylaxis in catheterized patients

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

Viral infections in children undergoing hematopoietic stem cell transplantation: report 2016 of Polish Pediatric Infectious Working Group of Polish Society of Pediatric Oncology and Hematology

BackgroundPolish Pediatric Infectious Working Group of Polish Society of Pediatric Oncology and Hematology continues from 2012 the infections monitoring program in pediatric hematopoietic stem cell transplant (HSCT) and onco-hematology centers.ObjectiveEpidemiological analysis of viral infections in children and adolescents undergoing HSCT in pediatric centers in 2012–2013 and 2014–2015.MethodsRetrospective analysis of viral infections after 650 HSCT in children and adolescents.ResultsAn increase in incidence in 2014–2015 was observed (60.6% vs 51.3%; OR=1.5; p=0.035) after allo-HSCT. Cumulative incidence after allo-HSCT (2012–2013 vs. 2014–2015) was: CMV – 28.0% vs. 29.2%, BKV – 18.5% vs. 22.8%, EBV – 15.5% vs. 24.3%, ADV – 9.5% vs. 5.2%, rotavirus – 9.1% vs. 5.6%, VZV – 2.6% vs. 1.1%, influenza – 0.9% vs. 3.4%, HHV6 – 0.9% vs. 1.5%, norovirus – 0% vs. 2.2%, RSV – 0% vs. 1.5%, parainfluenza – 0% vs. 0.7%, and MPV – 0% vs 0.4%. Infections after auto-HSCT occurred in 8 (10.5%) patients between 2012 and 2013 vs. 2 (2.6%) between 2014 and 2015. Cure rate after viral infections has increased (2012–2013 vs. 2014–2015) for: EBV – 90.7% vs. 100%, ADV – 93.8% vs. 100%, BKV – 94.2% vs. 96.8%, CMV – 94.6% vs. 98%, and remained 100% in infections with influenza, VZV, HHV6, rotavirus as well as in parainfluenza, RSV, and MPV. Decrease of deaths rate attributed to viral infections from 6.5% (2012–2013) to 0.7% (2014–2015) was observed after allo-HSCT.ConclusionsWe found epidemiological trends in viral infections after HSCT in children: increase in incidence after allo-HSCT (increase EBV, appearance of CARV) and decrease after auto-HSCT. Decrease of deaths attributed to viral infections was observed in the last period of time