Resistance Of Microflora Research Articles

Modern Didactics of Acute Pneumonia as a Side Effect of the Antibiotic Era

The widespread and uncontrolled use of antibiotics for more than eighty years, including not only medicine but also the food industry, has had a significant impact on the usual relationships between representatives of the microbiosphere that accompanies our body. For a long time, the possibility of side effects remained without due attention, giving way to attempts to maintain the original antimicrobial effect of these drugs. Currently, evidence of the consequences of antibiotic therapy has received official recognition only in the form of resistant microflora. Phenomena such as the constant change of AP pathogens and the gradual loss of antibiotics for their purpose remain unstudied. The selective nature of specialists' attention to the side effects of antibiotics is due to a decrease in their effectiveness and the desire to restore the successes of previous therapy. The latter circumstance is a consequence of the negative didactic influence of antibiotics on professional views that determine the strategy for solving the problem and require, first of all, changes following the fundamental canons of medical science and numerous facts.

Microflora of Secretions in a Surgical Hospital of Orthopedics and Traumatology Profile for 2021-2023 (SI “ITO NAMS of Ukraine”)

Summary. Healthcare-associated infections (HAIs), namely, surgical site infections, early postoperative and subsequent in-hospital infections, are the most common undesirable phenomenon in the world. According to statistics, at least one case of HAIs is diagnosed in every 100 hospitalized patients in hospitals of 7 developed and 15 other countries of the world at any given time. The occurrence of such complications during the treatment of a patient in a hospital leads to the need of additional diagnostic tests, additional courses of antibiotics, and unplanned surgical intervention. Worsening of the prognosis of treatment may occur due to the formation of the so-called resistant microflora in such patients, with a real probability of spreading the infection in the hospital. Prevention of HAIs in practice occurs through planned infection control in operating rooms and procedure rooms in clinical departments and qualified timely diagnostic work of certified microbiological laboratories in hospitals. Objective. The objective of the study was to determine the spectrum of microflora of secretions for three years (2021-2023) in orthopedic and trauma patients due to changes in modern injuries received more often because of military aggression and to propose the identified differences as criteria for prescribing antibacterial drugs in complex inpatient treatment. The work shows that over the past three years (2021-2023), the ratio of gram-positive and gram-negative microorganisms in the study material almost did not change and averaged 1.65. The peculiarity of the analyzed period was an increase in the number of methicillin-resistant staphylococci by 1.3 times. The spectrum of gram-negative clinical strains has changed, namely, the number of Kl.pneumoniae clinical strains with a high level of polyresistance has increased by 2.5 times. The obtained data made it possible to identify the spectrum of microflora of secretions in orthopedic and trauma patients with modern infectious complications, which prompts us to make changes in the standards of antibacterial treatment protocols, and to plan the needs for certain antibiotics in hospitals with personalization of their prescription to improve the effectiveness of treatment and reduce the risk of development of antimicrobial resistance.

On the assessment of the role of new antibiotics in pharmacotherapy algorithms for complicated intra-abdominal infections (literature review)

The goal: To analyze the topical problems in the use of the newest antibiotics in abdominal surgical interventions and approaches to their solution. Material and methods: The large-scale (as a rule) publications mostly of 2019–2023 on the issue were analyzed. The searching had been executed according to keywords in Pubmed (ncbi.nlm.nih.gov). Findings: Modern protected cephalosporins and carbapenems, as well as eravacycline, appear to be valuable tools in the treatment of surgical intra-abdominal infection, caused in particular by resistant microflora, especially when taking into account local data. The value of tigecycline in this nosology seems less obvious.

Antibiotic resistance risk assessment in Mymensingh, Bangladesh: Current scenario from human-animal-environmental interfaces viewpoint

The imprudent use of antibiotics increases the environmental microflora's resistance to various drugs, particularly antibiotics. Prescription data is crucial for understanding antibiotic usage frequency and dosage. This health-focused study aims to analyze antibiotic prescription patterns in human and veterinary practices to identify emerging trends in environmental antibiotic resistance.For this survey, A total of 6550 prescriptions were randomly collected from hospitals and pharmacies in Mymensingh sadar upazila, Bangladesh, between August and October 2022. Of these, 5123 (78 %) were for human cases and 1427 (22 %) for veterinary purposes. Photos of the prescriptions were taken and analyzed to understand prescribing habits. Additionally, 30 water samples from rivers, ponds, sewage, and households in Mymensingh City Corporation were collected to assess environmental antibiotic levels and resistance patterns of microorganisms.The analysis showed that Cephalosporins were the most prescribed antibiotics, found in 570 (56.27 %) of human prescriptions and 230 (42.99 %) of veterinary prescriptions. Aminoglycosides had the lowest frequency, with 13 (1.2 %) for humans and 46 (8.6 %) for animals. Macrolides (12.24 %), carboxylic acids (1.87 %), and rifamycins (1.28 %) were only found in human prescriptions, while sulfa drugs (10.84 %), tetracyclines (5.42 %), and combinations of antibiotics (14.77 %) were only in animal prescriptions. Quinolones were prescribed 4.06 times more for humans, while aminoglycosides were used 3.54 times more for animals. Environmental samples showed E. coli had the highest resistance (MAR Value: 0.625) against eight antibiotics.This study illuminates the human-animal prescription patterns that are influenced by environmental factors which drive antibiotic stewardship in Bangladesh. It is imperative for practitioners to exercise caution and adhere to guidelines when prescribing antibiotics, both in human and veterinary practices, given the alarming trend of antibiotic resistance. Additionally, measures must be taken to restrict the influx of antibiotics residue into the environment.

Philosophy and Morality of the Era of Antibiotics using the Example of Acute Pneumonia

The widespread and uncontrolled use of antibiotics for more than eighty years, including not only medicine, but also the food industry, has had a significant impact on the usual relationships between representatives of the microbiosphere that accompanies our body. For a long time, the possibility of side effects remained without due attention, giving way to attempts to maintain the original antimicrobial effect of these drugs. Currently, evidence of the consequences of antibiotic therapy has received official recognition only in the form of resistant microflora. Phenomena such as the constant change of AP pathogens and the gradual loss of antibiotics for their purpose remain unstudied. The selective nature of specialists' attention to the side effects of antibiotics is due to a decrease in their effectiveness and the desire to restore the successes of previous therapy. The latter circumstance is a consequence of the negative didactic influence of antibiotics on professional views that determine the strategy for solving the problem and require, first of all, changes in accordance with the fundamental canons of medical science and numerous facts.

PECULIARITIES OF THE INFLUENCE OF TYLOZIN ON THE METABOLISM OF PROTEINS AND AMINO ACIDS IN CHICKEN

Over the last decade, poultry farming, both for meat and eggs, has been widely developed in our country. Poultry products are widely used in the diets of the population. In this problem, it is necessary to observe the careful application of antimicrobial drugs to productive animals, as they are used by humans and not to disturb the ecosystem and not cause the formation of resistant microflora. Taking into consideration that veterinary medicine should be more preventive than curative, the problems of poultry treatment are poorly described, it was decided that it is necessary to work with healthy organisms. Because the physiological reactivity of the body changes with pathologies even without medical interventions. Methods of using macrolides and other pharmacological agents in sick animals and poultry are described in the literature, but there are not enough works that would highlight the data on the effect of this agent on protein and amino acid metabolism in healthy chickens. In addition, it is known that metabolic processes in poultry take place with a fairly high intensity, and this is definitely reflected in the amount of doses of various drugs, and antibiotics in particular. Medicines in the bird's body, accordingly, are biotransformed more quickly and removed from the body faster with droppings and eggs, others accumulate in various organs and muscles. Therefore, it is important to know how the biosynthesis of the main proteins and the level of free amino acids changes under the action of the antimicrobial agent Tylozin on the days of administration and in the period after the administration of the antibiotic. The results of the research are informative. The work is devoted to the study of the influence of an antimicrobial drug from the pharmacological group of macrolides on the metabolism of amino acids and proteins in chickens in a comparative aspect. At the same time, egg production in laying hens aged 140-150 days was taken into account. The influence of different doses of Tylosin on the protein and amino acid composition of chickens during the period of use and after the end of drug administration was studied. It was established that changes in the metabolism of total protein, its fractions and amino acid nitrogen in the blood serum occur naturally, long-term, in different directions and, proportionally, depend on the dose of the drug. The effect of the drug was studied in minimum, average and maximum doses.

ОСОБЕННОСТИ ТЕЧЕНИЯ ОСТРЫХ ОДОНТОГЕННЫХ ВОСПАЛИТЕЛЬНЫХ ПРОЦЕССОВ ЧЕЛЮСТЕЙ ВДЕТСКОМ ВОЗРАСТЕ

The goal.Studying the clinical course’s features of acute odontogenic inflammatory processes of the jaws in children, describing species composition of pathogens, determination sensitivity to antibiotics of various groups in acute odontogenic inflammatory processes of the jaws in childhood. Materials and methods.The case histories of 900 patients were analyzed, microbiological research methods were carried out (microscopic examination of clinical samples with Gram staining, culture method, determination of the sensitivity of theisolated pathogen to antimicrobial drugs).Results.The most common odontogenic inflammatory processes of the jaws were observed in children aged 4–5 years. In48,85 % of cases in a milk bite and in 67,92 % of cases in a permanent bite, the cause of the development of an odontogenic inflammatory process was complicated caries of the mandibular molars. 56% of children had a general condition. The leading causative agent of the inflammatory process of the jaws was in 65,6 % of cases hemolytic streptococcus. In other cases, Streptococcus Viridans(6,1 %), pneumococci (4,3 %), candida (3 %), Staphylococcus aureus(2,8 %), Moraxella cataralis(1,2 %), etc. were detected in the mixed microflora of purulent exudate. The drugs of choice for empirical antibiotic therapy for odontogenic inflammatory process caused by beta-hemolytic streptococcus group A are vancomycin (antibiotic sensitivity –99 %), fluoroquinolones (antibiotic sensitivity –98 %), beta-lactams (antibiotic sensitivity –91 %). The highest percentage of resistance of this microflora was noted to macrolides (41 %), and to clindamycin (33 %). The rapid spread of the purulent-inflammatory process in the maxillofacial region in acute odontogenic processes in children, the resistant microflora of the odontogenic purulent focus require a competent approach when providing emergency care.Conclusions.The obtained has great practical importance for the choice of rational antibiotic therapy.

Дослідження фунгіцидної дії дезінфекційного препарату «Діолайд»

Nowadays it is important to develop new disinfectants for poultry which are simple in use, non-toxic if used in the presence of birds, with a broad bactericidal spectrum, not causing the resistance of microflora, maintaining the air environment, linking ammonia and deodorizing the air. One of the product effectiveness indicators comes from testing on micromycetes which are persistent on the indoor surfaces and require high fungicidal concentrations of active substances. Research results of the effect produced by the “Diolide” disinfectant with 42% sodium chlorite and 46% sodium chloride base showed fungicidal activity against the etalon strains of Candida albicans ATCC 10231 and Aspergillus niger ATCC 16404. By serial digestion method using paper disks on Chapek’s medium and on the malt agar in the presence of the “Diolide” disinfectant the effective concentration of 0.1% was established. “Diolide” disinfectant at 0.1% concentration at 60 min. exposure completely disinfected test objects of wood, iron, brick and plaster which were contaminated with micromycetes. It was found that the effectiveness of “Diolide” disinfectant depends directly on the time of exposure and it is therefore necessary to adhere to these conditions in the production process.

Silver nanoparticles: an ecological method of synthesis, properties and use against antibiotic resistant microflora

A quantitative assessment of the antibacterial effect of silver nanoparticles on polyantibiotic-resistant grampositive and gram-negative microorganisms was carried out. Silver nanoparticles were synthesized by the environmentally friendly metal-steam synthesis method. The size and electronic state of nanoparticles were investigated by transmission electron and X-ray photoelectron spectroscopy. The antibacterial properties of nanomaterials were assessed on two clinical pathogenic strains of gram-positive and four strains of gram-negative microorganisms. The typing and assessment of bacterial resistance to antibiotics were carried out on a microbiological analyzer. The antibacterial effect of nanoparticles was quantitatively assessed using the dilution method and the determination of the minimum inhibitory and minimum bactericidal concentrations.It was found that the studied silver nanoparticles have sizes in the range from 5 to 24 nm with an average diameter of 10.8 nm. It was shown that all clinical strains of microorganisms used in the study are characterized by multiple antibacterial resistance; the percentage of their antibiotic resistance ranges from 12.5 to 93.3 %. It was found that for the studied microorganism, the values of the minimum inhibitory concentration (MIC) are in the range from 7.81 to 31.25 μg/ml, and the minimum bactericidal concentration (MBC) is in the range from 31.25 to 62.50 μg/ml. The obtained MIC and MBC data can be used to create promising antimicrobial drugs and medical next generation devices.

Особенности формирования антимикробной резистентности микроорганизмов на животноводческих комплексах при маститах у коров

A study of the resistance of microflora isolated from the secret of udder patients with cow mastitis showed high resistance of isolated microorganisms to antibiotics of penicillin, tetracycline cephalosporin, polymyxin, macrolides, glycopeptides and lincosamides. In determining the sensitivity of isolated microorganisms to complex antibacterial drugs, it was found that all strains of S. agalactiae showed resistance to all the drugs studied (Bayoclox DC, Mamifort secado, Mastiet forte, Mastizim, Norfloxamast, Primalact, C-mast). E. coli was resistant to 62,5% of the study drugs (Bayoclox DC, Mamifort secado, Mastizim, C-mast). S. aureus – to 50,0% of drugs. Antibiotic resistance of the groups of penicillins, tetracyclines, linkosamides of 1 generation was recorded in 100% of the strains studied. 56,6% E. col, 43,4% S. aureus and 80% S. agalactiae were resistant to fluoroquinolone preparations. 75% E. col, 60% S. aureus and 50% S. agalactiae were resistant to cefazoline antibiotics. E. coli did not show resistance to the group of aminoglycosides (gentamicin); of the isolates S. aureus and S. agalactiae, 20% were resistant.

Bactericidal activity of disinfectants

The modern market of drugs off ers a wide range of disinfectants. However, the constant use of the same drugs contributes to the development of resistance in the microfl ora and reduces the quality of activities. In this regard to develop eff ective measures to combat and prevent infectious diseases, it is necessary to periodically monitor the activity of disinfectants used in the enterprise. The purpose of the researches was to study the bactericidal eff ect of disinfectants on the microfl ora of poultry enterprises. The researches have been carried out at the Siberian Scientifi c and Research Institute of Poultry Farming – a branch of the Federal State Budgetary Scientifi c Institution “Omsk Agrarian Scientifi c Center”. The activity of 8 disinfectants to 37 test cultures isolated from poultry farms of diff erent productivity trends and species of poultry (chickens, turkeys, quails) has been tested. It has been found as a result of the conducted research that the most expressed bactericidal eff ect on gram-positive and gram-negative microorganisms were complex disinfectants, which included glutaraldehyde in combination with quaternary ammonium compounds. Thus, 1 % solutions of Gludesive and Viroshield provided the death of all test cultures, Dinovis Ultra and TN-4+ – 92 and 84 % of cultures. The disinfecting activity of Mirosan drug and formalin was most expressed for gram-positive microfl ora, among gram-negative microfl ora resistance was registered in 25–75 % and 25–50 % of cultures, respectively. Drugs EcoSide Advansa and Ecocide C have showed the lowest activity to all investigated microorganisms. The largest number of resistant cultures to the tested disinfectants have been registered in the bacteria of the genus Citrobacter spp. and Pseudomonas aeruginosa, while simultaneously noted resistance to 4–6 drugs.

Productive feeding of rainbow trout: properties, effects on physiological state and interior indicators

It is advisable to use secondary resources of the fish industry with high protein content as a raw material for the development of biologically complete feeds in aquaculture. The work uses standard and original research methods. A complex studies of the chemical composition, physico-chemical and microbiological quality indicators of the experimental feed proved its balance in amino acid composition. The degree of essential amino acids was 91.5 to 107.3%. The biological value of feed protein is 95.18%. It was proved that the amount of free ammonia released through the fish gills is directly proportional to the amount of feed eaten, inversely proportional to the feed coefficient and equal to 0.05. The pH value changed on the 42nd day from 7.6 to 7.7 but remained within the range of pH 6-9, which is optimal for the life support of fish. The absolute increase in the amount of individuals in the control group was 1.2% higher compared with the experimental one. At the same time, feed costs for the entire feeding period were 0.99. Fish survival was 98%. In both cases, bifidobacteria were isolated from the resistant microflora. Notably, the bifidobacteria titer was 3 lg units higher in the trout of the experimental group in comparison with the control group, which does not exceed permissible norms. Thus, the obtained feeding is not inferior in quality to the imported feeding. Therefore, it can be recommended for feeding rainbow trout grown in recirculating aquaculture systems.

Remediation of hexavalent chromium contaminated soil by nano-FeS coated humic acid complex in combination with Cr-resistant microflora.

A novel nano-composite material (CMC-FeS@HA) combining the advantages of humic acid (HA) and FeS was synthesized to remediate hexavalent chromium (Cr(VI)) contaminated soil along with chromium (Cr) resistant microflora. The characteristic analysis confirmed the successful synthesis of the nano-composite, which provided further mechanism evidence of its detoxification effect on polluted soil. Energy Dispersive System analysis proved the adsorption of the microbe consortium (MC) for Cr. After remediation, Cr(VI) in all treatments was dramatically reduced and the leachable Cr in soil treated by CMC-FeS@HA and MC decreased 89.14% compared with control. The result of BCR sequential extraction showed that Cr was stabilized, whose form changed to oxidizable and residual from HOAC-extractable. Besides, CMC-FeS@HA, as a sustained-release acid with high biocompatibility, could continuously decrease the pH of strongly alkaline soil and created a suitable micro-ecological environment for soil microorganisms. Moreover, CMC-FeS@HA dramatically improved soil physicochemical property, soil microbial activity (dehydrogenase, hydrolase, urease, and invertase activities), and soil microecological diversity. In total, this study provided a useful technology for soil remediation, which innovatively combined chemical remediation and microbial-remediation with a positive effect on soil quality, providing a good approach for the multiple technology combination in the environmental cause.

The role of a gram-positive microflora and its resistance in purulent-necrotic complications in patients, suffering syndrome of diabetic foot

Objective. To improve the results of treatment in patients, suffering diabetic foot syndrome (DFS), using conduction of the directed antibacterial therapy, taking into account the resistance of microflora revealed, and to reveal the role of a gram-positive microflora in occurrence of complications.
 Materials and methods. There were examined 1824 patients, suffering DFS for period from 2015 to 2019 yr., who suffered purulent-necrotic affections of the foot - abscess, phlegmon, purulent tendovaginitis, purulent arthritis, gangrene. All the patients suffered diabetes mellitus Type 2, average duration of which have constituted (12.3 ± 2.7) yrs. Qualitative content of microflora and sensitivity of cultures for antibiotics were revealed on automatic microbiological analizators «Vitek2» and BacT/ALERT (France).
 Results. The cause of purulent-necrotic complications was a gram-positive microflora, which in 57.1 - 66.8% patients was diagnosed in monoinfection and prevailed in a content of microbial associations. Phenomena of resistance to the main antibacterial preparations was revealed in 37.4% bacteria. The biggest resistance have had Staphylococcus aureus and Enterococcus faecalis. In 62.5% patients, owing Staphylococcus aureus, a resistance gene to Staphylococcus aureus with three genetic variations were revealed, which differed in accordance to resistance for certain groups of antibiotics. The most significant MRSA Type 3 - panresistant (in 6/2% patients).
 Conclusion. Investigations of purulent-necrotic foci in patients with the DFS witnesses, that the leading microorganism while development of complications constitutes a gram-positive microflora, which is characterized by presence of polyresistant and panresistant strains. Such a condition gives background to necessity for correcting of the antibacterial therapy administered.

ЭКОЛОГИЧЕСКИЕ ОСОБЕННОСТИ УСТОЙЧИВОСТИ К АНТИБИОТИКАМ УСЛОВНО-ПАТОГЕННОЙ МИКРОФЛОРЫ, ПЕРСИСТИРУЮЩЕЙ В ГИДРОЭКОСИСТЕМАХ

The article provides an overview of investigating antibiotic resistance of conditionally pathogenic microflora circulating in different hydroecosystems. It has been stated that the process of spreading antibiotic resistance in bacteria around the world is progressing in a large scale. It has been found that the peculiarities of its manifestation are largely determined by natural, climatic and anthropogenic factors, as well as by the level of urbanization. Mechanisms of microorganism interaction with separate antibiotics are studied. The data obtained show that antibiotics widely used in medicine, veterinary science and aquaculture have caused antibiotic resistance in microflora isolated from hydroecosystems and hydrobionts (fish). The study results of the Russian and foreign scientists on antibiotic resistance of bacteria isolated from water and fish have been brought. Thus, microorganisms isolated from urban watercourses of Astrakhan, the Volga river Delta and pike perch body organs showed multiple antibiotic resistance depending on the season and the studied area. In all cases there have been recorded the minimum resistance of microflora to tobramycin and chloramphenicol and the maximum - to benzylpenicillin and ampicillin. The obtained data can serve as indicators of sanitary and epidemiological and environmental problems of hydroecosystems.

The effect of microflora resistance to antibiotics on the outcomes of the treatment of patients with severe craniocerebral injury

The effect of microflora resistance to antibiotics on the outcomes of the treatment of patients with severe craniocerebral injury

Post-Obstructive Pneumonia in Patients with Cancer: A Review.

Published literature on post-obstructive pneumonia is difficult to find and consists mainly of case reports or small case series. This entity is encountered most often in patients with advanced lung malignancy but is also occasionally seen in patients with community-acquired pneumonia (CAP). There are substantial differences in the manifestations, treatment, and outcomes of post-obstructive pneumonia in these two settings. When obstruction is present in patients with CAP, it is almost always secondary to an underlying pulmonary malignancy. In fact, the observation of an obstructive component in patients with CAP leads to the detection of primary or metastatic lung cancer in more than 50% of such individuals. Post-obstructive pneumonia in patients with advanced lung malignancy is far more common (~ 50% of patients) and is associated with substantial morbidity and mortality. The management of these patients is very challenging and involves multiple disciplines including medical oncology, pulmonary medicine, infectious diseases, intervention radiology, surgery, and intensive care teams. The administration of broad-spectrum antibiotic regimens is generally required. Refractory or recurrent infections despite the administration of appropriate antimicrobial therapy are the norm. Frequent and prolonged antibiotic administration leads to the development of resistant microflora. Complications such as lung abscess, empyema, and local fistula formation develop often. Relief of obstruction generally produces only temporary symptomatic improvement.

ОСОБЛИВОСТІ БІОЦЕНОЗУ ТА ФУНКЦІОНАЛЬНОЇ АКТИВНОСТІ ВАГІНАЛЬНОГО ЕПІТЕЛІЮ ПРИ МІСЦЕВОМУ ЛІКУВАННІ НЕСПЕЦИФІЧНОГО ВАГІНІТУ

Мета дослідження – оцінити клінічну та мікробіологічну ефективність і безпечність застосування препарату «Кломезол» у лікуванні неспецифічного вагініту.Матеріали та методи. Для вирішення поставленого завдання проведено обстеження і лікування 60 жінок репродуктивного віку з діагнозом аеробного вагініту. Проведено оцінку клінічної та мікробіологічної ефективності терапії у пацієнток з аеробним вагінітом. Вивчено терміни зникнення об’єктивних і суб’єктивних симптомів запального процесу, особливості функціональної активності епітелію піхви, вплив препарату на стан нормальної мікрофлори піхви. Дослідження проведено відповідно до міжнародних нормативів і правил GCP.Результати дослідження та їх обговорення. У результаті проведеного дослідження було встановлено, що комбінований препарат «Кломезол» у вигляді вагінальних свічок є ефективним по відношенню до умовно-патогенних мікроорганізмів – збудників аеробного вагініту і є препаратом вибору для лікування бактеріального вагінозу та аеробного вагініту. Кломезол не здійснює імуносупресивного впливу на епітелій піхви, завдяки цьому відновлення функціональної активності епітелію після лікування кломезолом відбувається швидше, ніж після лікування тержинаном. Відмічено покращення якості життя пацієнток після лікування.Висновки. Відмічена висока ефективність комбінованого препарату «Кломезол» по відношенню до широкого спектра мікрофлори, доведена висока терапевтична активність та безпечність у використанні у пацієнток з аеробними вагінітами. Кломезол добре переноситься та не викликає резистентності мікрофлори. Препарат може використовуватись у ІІ і ІІІ триместрах вагітності.

A gene cluster for the biosynthesis of moenomycin family antibiotics in the genome of teicoplanin producer Actinoplanes teichomyceticus.

Moenomycins are phosphoglycolipid antibiotics notable for their extreme potency, unique mode of action, and proven record of use in animal nutrition without selection for resistant microflora. There is a keen interest in manipulation of structures of moenomycins in order to better understand their structure-activity relationships and to generate improved analogs. Only two almost identical moenomycin biosynthetic gene clusters are known, limiting our knowledge of the evolution of moenomycin pathways and our ability to genetically diversify them. Here, we report a novel gene cluster (tchm) that directs production of the phosphoglycolipid teichomycin in Actinoplanes teichomyceticus. Its overall genetic architecture is significantly different from that of the moenomycin biosynthesis (moe) gene clusters of Streptomyces ghanaensis and Streptomyces clavuligerus, featuring multiple gene rearrangements and two novel structural genes. Involvement of the tchm cluster in teichomycin biosynthesis was confirmed via heterologous co-expression of amidotransferase tchmH5 and moe genes. Our work sets the background for further engineering of moenomycins and for deeper inquiries into the evolution of this fascinating biosynthetic pathway.

Microbial dynamics during shelf-life of industrial Ricotta cheese and identification of a Bacillus strain as a cause of a pink discolouration

Dairy products are perishable and have to be preserved from spoilage during the food chain to achieve the desired shelf-life. Ricotta is a typical Italian soft dairy food produced by heat coagulation of whey proteins and is considered to be a light and healthy product. The shelf-life of Ricotta could be extended, as required by the international food trade market; however, heat resistant microflora causes spoilage and poses issues regarding the safety of the product. Next-generation sequencing (NGS) applied to the Ricotta samples defined the composition of the microbial community in-depth during the shelf-life. The analysis demonstrated the predominance of spore-forming bacteria throughout the shelf-life, mostly belonging to Bacillus, Paenibacillus and Clostridium genera. A strain involved in spoilage and causing a pink discolouration of Ricotta was isolated and characterised as Bacillus mycoides/weihenstephanensis. This is the first report of a food discolouration caused by a toxigenic strain belonging to the Bacillus cereus group that resulted the predominant strain in the community of the defective ricotta. These results suggest that the processing of raw materials to eliminate spores and residual microflora could be essential for improving the quality and the safety of the product and to extend the shelf-life of industrial Ricotta.