Viable Microbes Research Articles

Effect of water containing organic acids on aspiration pneumonia-causative bacteria in the biofilm on the tooth surface

Background/purposeThe tooth surface is a source of oral microbes in dentulous individuals, it is difficult for elderly people requiring nursing care to perform mechanical tooth cleaning by themselves. The objective of this study was to investigate the antimicrobial effect of water containing organic acids (WOA) made by some organic acids as food additives on chemical cleaning for elderly people on aspiration pneumonia-causative bacteria in the biofilm on the tooth surface. Materials and methodsNinety-six specimens made from bovine incisors were divided into four groups and incubated with one of four aspiration pneumonia-causative bacteria. Each group was further divided into six subgroups according to treatment as follows: control group (DW), chlorhexidine gluconate solution group (CHX), WOA group (WOA), ultrasonic treatment in distilled water group (DW-U), ultrasonic treatment in chlorhexidine gluconate solution group (CHX-U) or ultrasonic treatment in WOA group (WOA-U). After treatment, the levels of viable microbes in the biofilm were evaluated by quantitative adenosine triphosphate analysis and compared among the six groups. ResultsFor every evaluated microbe, there were significant differences between DW and WOA, and DW and WOA-U. However, there was no significant difference among the WOA, DW-U, CHX-U and WOA-U groups. These results suggested that the antimicrobial effect of WOA on microbes attached to the tooth surface was similar to that of ultrasonic cleaning. ConclusionWOA has an antimicrobial effect on microbes in the biofilm on the tooth surface.

Filthy lucre: A metagenomic pilot study of microbes found on circulating currency in New York City.

BackgroundPaper currency by its very nature is frequently transferred from one person to another and represents an important medium for human contact with—and potential exchange of—microbes. In this pilot study, we swabbed circulating $1 bills obtained from a New York City bank in February (Winter) and June (Summer) 2013 and used shotgun metagenomic sequencing to profile the communities found on their surface. Using basic culture conditions, we also tested whether viable microbes could be recovered from bills.ResultsShotgun metagenomics identified eukaryotes as the most abundant sequences on money, followed by bacteria, viruses and archaea. Eukaryotic assemblages were dominated by human, other metazoan and fungal taxa. The currency investigated harbored a diverse microbial population that was dominated by human skin and oral commensals, including Propionibacterium acnes, Staphylococcus epidermidis and Micrococcus luteus. Other taxa detected not associated with humans included Lactococcus lactis and Streptococcus thermophilus, microbes typically associated with dairy production and fermentation. Culturing results indicated that viable microbes can be isolated from paper currency.ConclusionsWe conducted the first metagenomic characterization of the surface of paper money in the United States, establishing a baseline for microbes found on $1 bills circulating in New York City. Our results suggest that money amalgamates DNA from sources inhabiting the human microbiome, food, and other environmental inputs, some of which can be recovered as viable organisms. These monetary communities may be maintained through contact with human skin, and DNA obtained from money may provide a record of human behavior and health. Understanding these microbial profiles is especially relevant to public health as money could potentially mediate interpersonal transfer of microbes.

Non-linear hydroxyl radical formation rate in dispersions containing mixtures of pyrite and chalcopyrite particles

The formation of hydroxyl radicals was studied in mixed pyrite-chalcopyrite dispersions in water using the conversion rate of adenine as a proxy for hydroxyl radical formation rate. Experiments were conducted as a function of pH, presence of phosphate buffer, surface loading, and pyrite-to-chalcopyrite ratio.The results indicate that hydroxyl radical formation rate in mixed systems is non-linear with respect to the rates in the pure endmember dispersions. The only exception is a set of experiments in which phosphate buffer is used. In the presence of phosphate buffer, the hydroxyl radical formation is suppressed in mixtures and the rate is close to that predicted based on the reaction kinetics of the pure endmembers.The non-linear hydroxyl radical formation in dispersions containing mixtures of pyrite and chalcopyrite is likely the result of two complementary processes. One is the fact that pyrite and chalcopyrite form a galvanic couple. In this arrangement, chalcopyrite oxidation is accelerated, while pyrite passes electrons withdrawn from chalcopyrite to molecular oxygen, the oxidant. The incomplete reduction of molecular oxygen leads to the formation of hydrogen peroxide and hydroxyl radical. The galvanic coupling appears to be augmented by the fact that chalcopyrite generates a significant amount of hydrogen peroxide upon dispersal in water. This hydrogen peroxide is then available for conversion to hydroxyl radical, which appears to be facilitated by pyrite as chalcopyrite itself produces only minor amounts of hydroxyl radical. In essence, pyrite is a “co-factor” that facilitates the conversion of hydrogen peroxide to hydroxyl radical. This conversion reaction is a surface-mediated reaction.Given that hydroxyl radical is one of the most reactive species in nature, the formation of hydroxyl radicals in aqueous systems containing chalcopyrite and pyrite has implications for the stability of organic molecules, biomolecules, the viability of microbes, and exposure to dust containing the two metal sulfides may present a health burden.

Probiotics in Curing Allergic and Inflammatory Conditions - Research Progress and Futuristic Vision.

Probiotics constitute the viable and beneficial microbes, which offer a dietary means to sustain the balance of gastro-intestinal (GI) microflora. Owing to their multiple health benefits, these have recently gained wide attention among researchers for exploring their potential in safeguarding the health of humans and animals. Probiotics could also modulate host-immune responses, thereby help in counteracting the immunological dysfunctions. Probiotics can inhibit the systemic invasion of pathogens entering through the GI mucosa/ oral cavity and have been found to possess effective prophylactic and therapeutic utilities against various infectious pathogens as well as non-infectious diseases and disorders. The present review expedites the role of probiotics in curing the ailments related to allergic and inflammatory disease conditions. A thorough reviewing of the literature and patents available on probiotics and their role in countering inflammation and allergy was conducted using authentic published resources available on Medline, PubMed, PubMed Central, Science Direct and other scientific databases. The information retrieved has been compiled and analysed pertaining to the theme of the study. Various micro-organisms have been evaluated for their probiotic efficacy, among these, the lactic acid bacteria viz. Lactobacillus sp. and Bifidobacterium sp. have extensively been studied and widely exploited. In the current post-globalized era of self and complementary medicines, the concept of probiotics and their therapeutic as well as prophylactic usage is gaining wide acceptance. As more and more bacterial strains are being proven for their pronounced influence on down regulation of immune regulation, atopic, inflammatory conditions, the use of probiotics is getting increased especially in the developed countries where such indications are high in prevalence. Apart from usage in immune related disorders, probiotics have been found to be effective in treating pouchitis, infantile diarrhoea due to infections, bacterial vaginosis, urinary tract infections, dental carries, diabetes, cancers as well augmenting the gut mucosal tolerance to various antibiotics and lactose intolerance. The resent review gives an insight towards potent utility of this branch of beneficial microbial therapy in allergy and inflammations, which is still in the emerging phase and more scientific evidences need to be explored regarding exploration of the mechanisms of action, further experimental trials and validation of controlled clinical studies in humans along with designing novel strategies for monitoring the possible microbial changes in their composition and metabolism associated with their interaction upon host immune system.

Bioaerosol generation by raindrops on soil

Aerosolized microorganisms may play an important role in climate change, disease transmission, water and soil contaminants, and geographic migration of microbes. While it is known that bioaerosols are generated when bubbles break on the surface of water containing microbes, it is largely unclear how viable soil-based microbes are transferred to the atmosphere. Here we report a previously unknown mechanism by which rain disperses soil bacteria into the air. Bubbles, tens of micrometres in size, formed inside the raindrops disperse micro-droplets containing soil bacteria during raindrop impingement. A single raindrop can transfer 0.01% of bacteria on the soil surface and the bacteria can survive more than one hour after the aerosol generation process. This work further reveals that bacteria transfer by rain is highly dependent on the regional soil profile and climate conditions.

Corrosion of carbon steel in clay environments relevant to radioactive waste geological disposals, Mont Terri rock laboratory (Switzerland)

Carbon steel is widely considered as a candidate material for the construction of spent fuel and high-level waste disposal canisters. In order to investigate corrosion processes representative of the long term evolution of deep geological repositories, two in situ experiments are being conducted in the Mont-Terri rock laboratory. The iron corrosion (IC) experiment, aims to measure the evolution of the instantaneous corrosion rate of carbon steel in contact with Opalinus Clay as a function of time, by using electrochemical impedance spectroscopy measurements. The Iron Corrosion in Bentonite (IC-A) experiment intends to determine the evolution of the average corrosion rate of carbon steel in contact with bentonite of different densities, by using gravimetric and surface analysis measurements, post exposure. Both experiments investigate the effect of microbial activity on corrosion. In the IC experiment, carbon steel showed a gradual decrease of the corrosion rate over a period of 7 years, which is consistent with the ongoing formation of protective corrosion products. Corrosion product layers composed of magnetite, mackinawite, hydroxychloride and siderite with some traces of oxidising species such as goethite were identified on the steel surface. Microbial investigations revealed thermophilic bacteria (sulphate and thiosulphate reducing bacteria) at the metal surface in low concentrations. In the IC-A experiment, carbon steel samples in direct contact with bentonite exhibited corrosion rates in the range of 2 µm/year after 20 months of exposure, in agreement with measurements in absence of microbes. Microstructural and chemical characterisation of the samples identified a complex corrosion product consisting mainly of magnetite. Microbial investigations confirmed the limited viability of microbes in highly compacted bentonite.

Concentrations and size distributions of viable bioaerosols under various weather conditions in a typical semi-arid city of Northwest China

In recent years, atmospheric particulate matter (PM) has become one of the top pollutants affecting the air quality and human health in Xi’an, the largest city in semi-arid inland of China. Few studies have been carried out on the microbial fraction of PM (defined as bioaerosols) in this region, especially under specific weather conditions. In this study, airborne microbial samples in Xi’an city were collected from Aug. 2014 to Jul. 2015. The concentrations and size distributions of airborne viable bacteria and fungi were characterized under different weather conditions (e.g. sunny, cloudy, rainy and hazy days). The results showed that the concentrations of airborne viable microbes in Xi’an were lower than those in most cities worldwide due to the semi-arid climate feature. The concentrations of airborne viable microbes varied by weather conditions, with the highest value observed on hazy days and the lowest observed on rainy days. In particular, the mean concentrations of viable bacteria and fungi on the hazy days (1311±371 and 896±559CFU/m3) exceeded the recommended permissible limit values in China. Moreover, the size distribution of airborne viable bacteria presented a similar unimodal pattern under four weather conditions, while no clear distribution pattern for airborne viable fungi was found in the non-haze weathers. Another important finding was that more than 60% viable bioaerosols were in respirable size range under all weather conditions. The present results can improve our understanding on the influence of viable bioaerosols on human health and air quality in semi-arid regions under various weather conditions.

Detection of microorganisms on formalin-fixed and stored pathology tissues: A microbiological study

Background:Formalin is widely used to fix histological preparations and as preservatives in embalming solutions and is an age-long practice in medical laboratories. It is generally accepted that the risk of contracting infections is relatively high among medical laboratory workers and pathologists. Recent studies have, however, suggested that formalin does not effectively inactivate all kinds of microbes in formalin-fixed tissue (FFT). Long time preserved tissues in formalin may develop growth of microbes on the surface of the formalin.Aims and Objectives:The purpose of the study is to determine the growth of microorganisms on the surface of FFTs.Materials and Methods:Fifty-one containers of 10% formalin with fixed tissues and undiscarded formalin solution not containing tissues of years 2013–2015 (17 in each year) were selected, and samples for inoculation onto the cysteine lactose electrolyte deficient agar plates were taken from the surface of the FFT using sterile cotton tips. The growth of the colonies was checked for after 48 h.Results:Out of 51 samples from 2013 to 2015, 17 had shown growth of microbial colonies. Six out of 17 samples of 2013, 7 out of 17 of 2014 and 4 out of 17 samples of 2015 had colonies of microbes on agar plates. Gram-negative bacilli, Bacillus subtilis and micrococci were mostly found.Conclusion:There were viable microbes on the surfaces of formalin solution containing pathology tissue. Since cross-contamination by microbes may occur during regrossing or processing, protocols to decrease cross-contamination should be instituted.

High-Throughput Sequencing of Viable Microbial Communities in Raw Pork Subjected to a Fast Cooling Process.

This study aimed to investigate the effect of the fast cooling process on the microbiological community in chilled fresh pork during storage. We established a culture-independent method to study viable microbes in raw pork. Tray-packaged fresh pork and chilled fresh pork were completely spoiled after 18 and 49 d in aseptic bags at 4 °C, respectively. 16S/18S ribosomal RNAs were reverse transcribed to cDNA to characterize the activity of viable bacteria/fungi in the 2 types of pork. Both cDNA and total DNA were analyzed by high-throughput sequencing, which revealed that viable Bacteroides sp. were the most active genus in rotten pork, although viable Myroides sp. and Pseudomonas sp. were also active. Moreover, viable fungi were only detected in chilled fresh pork. The sequencing results revealed that the fast cooling process could suppress the growth of microbes present initially in the raw meat to extend its shelf life. Our results also suggested that fungi associated with pork spoilage could not grow well in aseptic tray-packaged conditions.

Exploring environmental systems and processes through next-generation sequencing technologies: insights into microbial response to petroleum contamination in key environments

Environmental degradation due to petroleum contamination is a widespread phenomenon and can cause irreparable damage to the ecosystem if not contained. Microbial bioremediation has been established as an ecologically and economically viable method for the restoration of environments afflicted with xenobiotic and anthropogenic pollution. Effective execution of bioremediation strategies however, require a thorough understanding of the resident microbial community structure and function along with critical environmental factors. Recent innovative advances such as massively parallel sequencing, coupled with the development of robust bioinformatics tools have provided critical insights into the process of microbial bioremediation in the environment through elucidation of microbial community structures in uncontaminated and contaminated and/or bioaugmented systems with unprecedented efficiency and reproducibility. Aided by next-generation sequencing applications like metagenomics, metatranscriptomics and metagenomic shotgun sequencing, microbiologists have been able to investigate microbial responses to oil pollution with unparalleled completeness, even from extreme environments. The elucidation of the contribution of non-cultivable but viable microbes in oil contaminated sites have furnished us with essential information about the complex microbial associations and interdependencies that are required to facilitate effective remediation of contaminated environments. The current review focuses on microbial responses to oil contamination in various key environments unraveled through the use of NGS technologies, the characteristic features of such responses, and identification of critical factors necessary to facilitate efficient and systemic bioremediation of these polluted environments.

Microbiota is a primary cause of pathogenesis of chronic wounds.

Diverse microorganisms present on the surface of chronic wounds have been established to constitute wound microbiota. The aims of this study were to quantify the viability of wound microbiota, classify dispersal of viable microbes from the wound, and determine if human wound microbiota can produce a chronic wound in an animal model. Wound microbiotas as units (multiple microbial species acting as one infectious agent) were obtained from well-defined human chronic wounds and seeded onto mouse surgical excision wounds to produce chronically infected wounds that closely resembled the chronic wounds observed in the original hosts. We found the wound microbiota harvested from 35 out of 43 (81%) patients could produce similar chronic wounds (producing slough and exudate) in a murine chronic wound model. The top 30 species present in patient wounds were identified in the mouse wounds by molecular sequencing. Koch's postulates could therefore be applied to establish wound microbiota as the cause of the original human chronic wound infections. Evidence-based medicine criteria such as Hill's criteria for causation can all be satisfied by what is currently known about wound microbiota. This study demonstrates that wound microbiota actively disseminates from the chronic wound by forces and mechanisms intrinsic to the wound. Koch's postulates and Hill's criteria for causation together suggest chronic wound microbiota to be the main cause underlying the pathogenesis of chronic wounds. RW has an equity interest in PathoGenius Labs. No funding was received for this study.

Staying Alive: Measuring Intact Viable Microbes with Electrospray Ionization Mass Spectrometry.

Mass spectrometry has traditionally been the technology of choice for small molecule analysis, making significant inroads into metabolism, clinical diagnostics, and pharmacodynamics since the 1960s. In the mid-1980s, with the discovery of electrospray ionization (ESI) for biomolecule analysis, a new door opened for applications beyond small molecules. Initially, proteins were widely examined, followed by oligonucleotides and other nonvolatile molecules. Then in 1991, three intriguing studies reported using mass spectrometry to examine noncovalent protein complexes, results that have been expanded on for the last 25 years. Those experiments also raised the questions: How soft is ESI, and can it be used to examine even more complex interactions? Our lab addressed these questions with the analyses of viruses, which were initially tested for viability following electrospray ionization and their passage through a quadrupole mass analyzer by placing them on an active medium that would allow them to propagate. This observation has been replicated on multiple different systems, including experiments on an even bigger microbe, a spore. The question of analysis was also addressed in the early 2000s with charge detection mass spectrometry. This unique technology could simultaneously measure mass-to-charge and charge, allowing for the direct determination of the mass of a virus. More recent experiments on spores and enveloped viruses have given us insight into the range of mass spectrometry's capabilities (reaching 100 trillion Da), beginning to answer fundamental questions regarding the complexity of these organisms beyond proteins and genes, and how small molecules are integral to these supramolecular living structures. Graphical Abstract ᅟ.

Effects of minimal exposures to atmospheric pressure plasma on the activity of Salmonella Typhimurium: Deactivation of bacterial motility and suppression of host-cell invasion

Atmospheric pressure plasma (APP) has been shown effective in sterilization by reducing the number of viable microbes during surface cleaning, food processing, or human tissue treatment. For safe conduct, the majority of previous research focused on complete abolition of microbes, which may require severe treatments. Our aim is to investigate the minimal treatment conditions necessary for effective inactivation of bacteria in such a manner that the APP treated bacteria would not be able to harm the host cells. For this, we ought to identify the objective criteria to make the bacteria dysfunctional. We choose the motile properties and the host-cell invasion capability as two measures to quantify the pathogenic state of bacteria. In this paper, we investigated how the APP treatment in a minimal dosage affects the activity of Salmonella Typhimurium. At 100 W and 15 kHz for 20 s, the APP treatment effectively suppressed active “run and tumble” type motility and induced formation of abnormally long structures. With 20 s exposure, the bacterial cells failed to cause pyroptosis in the host cells with >90% survival after 12 h of co-incubation. Our results suggest novel measures to evaluate the functional pathogenic state for identifying safe APP treatment conditions.

Survivability of bare, individual Bacillus subtilis spores to high-velocity surface impact: Implications for microbial transfer through space

Laboratory experiments show that endospores of Bacillus subtilis survive impact against a solid surface at velocities as high as 299±28m/s. During impact, spores experience and survive accelerations of at least 1010m/s2. The spores were introduced into a vacuum chamber using an electrospray source and accelerated to a narrow velocity distribution by entrainment in a differentially pumped gas flow. Different velocity ranges were studied by modifying the gas flow parameters. The spores were electrically charged, allowing direct measurement of the velocity of each spore as it passed through an image charge detector prior to surface impact. Spores impacted a glass surface and were collected for subsequent analysis by culturing. Most spores survived impact at all measured velocities. These experiments differ fundamentally from other studies that show either shock or impact survivability of bacteria embedded within or on the surface of a projectile. Bacteria in the present experiments undergo a single interaction with a solid surface at the full impact velocity, in the absence of any other effects such as cushioning due to microbe agglomerations, deceleration due to air or vapor, or transfer of impact shock through solid or liquid media. During these full-velocity impact events, the spores experience extremely high decelerations. This study is the first reported instance of accelerations of this magnitude experienced during a bacteria impact event. These results are discussed in the context of potential transfer of viable microbes in space and other scenarios involving surface impacts at high velocities.

Practical toolkit for monitoring endoscope reprocessing effectiveness: Identification of viable bacteria on gastroscopes, colonoscopes, and bronchoscopes

Experts have recommended microbiologic surveillance by external reference laboratories for certain flexible endoscopes. There is currently insufficient evidence on the feasibility and utility of cultures. Researchers evaluated a preassembled toolkit for collecting and processing samples from endoscopes. A pilot study was performed in a large academic medical center. A toolkit was used to aseptically sample biopsy ports and suction/biopsy channels of 5 gastroscopes, 5 colonoscopes, and 5 bronchoscopes after full reprocessing. Blinded specimens were packaged and transported on icepacks to a reference laboratory that used standard methodologies for microbial cultures. The laboratory detected bacteria in samples from 60% of patient-ready endoscopes, including gram-positive and gram-negative species. Viable microbes (<10 CFU) were recovered from 2 gastroscopes, 3 colonoscopes, and 4 bronchoscopes. Stenotrophomonas maltophilia and Delftia acidovorans were recovered from all 3 endoscope types. Subsequent environmental testing detected S maltophilia in the reprocessing rinse water. A preassembled toolkit facilitated the aseptic collection of samples for culturing by a reference laboratory that detected viable microbes on fully reprocessed endoscopes. Speciation allowed identification of potential pathogens and a possible common contamination source, demonstrating that microbial cultures may have value even when colony counts are low.

Inactivation of Airborne Bacteria and Viruses Using Extremely Low Concentrations of Chlorine Dioxide Gas

Infectious airborne microbes, including many pathological microbes that cause respiratory infections, are commonly found in medical facilities and constitute a serious threat to human health. Thus, an effective method for reducing the number of microbes floating in the air will aid in the minimization of the incidence of respiratory infectious diseases. Here, we demonstrate that chlorine dioxide (ClO₂) gas at extremely low concentrations, which has no detrimental effects on human health, elicits a strong effect to inactivate bacteria and viruses and significantly reduces the number of viable airborne microbes in a hospital operating room. In one set of experiments, a suspension of Staphylococcus aureus, bacteriophage MS2, and bacteriophage ΦX174 were released into an exposure chamber. When ClO₂ gas at 0.01 or 0.02 parts per million (ppm, volume/volume) was present in the chamber, the numbers of surviving microbes in the air were markedly reduced after 120 min. The reductions were markedly greater than the natural reductions of the microbes in the chamber. In another experiment, the numbers of viable airborne bacteria in the operating room of a hospital collected over a 24-hour period in the presence or absence of 0.03 ppm ClO₂ gas were found to be 10.9 ± 6.7 and 66.8 ± 31.2 colony-forming units/m³ (n = 9, p < 0.001), respectively. Taken together, we conclude that ClO₂ gas at extremely low concentrations (≤0.03 ppm) can reduce the number of viable microbes floating in the air in a room. These results strongly support the potential use of ClO₂ gas at a non-toxic level to reduce infections caused by the inhalation of pathogenic microbes in nursing homes and medical facilities.

Antibacterial capacity of cavity disinfectants against Streptococcus mutans and their effects on shear bond strength of a self-etch adhesive.

We evaluated the antibacterial properties of three disinfectants [2% chlorhexidine (CHX), 6% sodium hypochlorite (NaOCl), and 0.01% urushiol)] against Streptococcus mutans and their effects on bond strength of Scotchbond(TM) Universal. The reduction in bacterial growth was evaluated by the colony counting method. Total 105 specimens were assigned to seven groups, according to surface pretreatment: control group (C) without pretreatment; chlorhexidine gluconate with rinse (CR) or without rinse (CD); NaOCl with rinse (NR) or without rinse (ND); and urushiol with rinse (UR) or without rinse (UD). The shear bond test was performed at a cross-head speed of 0.5 mm/min. None of the disinfected specimens had viable microbes after a 30 min incubation. The control group exhibited the strongest bond; however, no significant difference was detected with the disinfectant-treated groups, except weak bonding with ND group. These findings suggest that all disinfectants tested had strong antibacterial capacity and may better be rinsed away.

Currently Available Rapid Microbial Tests for Translational Medicine

Rapid microbial tests ensure testing in rapid and accurate manners at reasonable costs. The ideal test should achieve detection of certain types of microorganisms that are undetected by the pharmacopoeia-defined sterility tests and its accuracy should be confirmed by regulatory authorities. The use of pharmacopoeia sterility tests is limited since they can detect only microorganisms that are viable only in specified media. A rapid test that can detect viable bacteria and microbes that cannot be cultured and never fails in bacterial detection, should appeal to the regulatory authorities. In the agar mediumculture system employed in the pharmacopoeia-microbial test, the test results may be erroneously false negative when the viable bacteria fail to grow under the defined incubation conditions, when inhibitors are present in the test sample, or when scientific approaches are not available to differentiate negative from false negative results. On the other hand, rapid microbial tests with false positive results due to noise caused by detection principle, measurement device, or non-biologic positive substance, imposes huge industrial challenges. In this review, we discuss the rapid microbial tests classified according to various systems for detection of microorganisms and their application, and then introduce some commercial applications of existing devices for detection of microorganisms and provide details of microbial test features, and compare the purposes of the microbial tests.

Bacterial Associations Across House Fly Life History: Evidence for Transstadial Carriage From Managed Manure.

House flies (Diptera: Muscidae; Musca domestica L.) associate with microbe-rich substrates throughout life history. Because larvae utilize bacteria as a food source, most taxa present in the larval substrate, e.g., manure, are digested or degraded. However, some species survive and are present as third-instar larvae begin pupation. During metamorphosis, many bacteria are again lost during histolysis of the larval gut and subsequent remodeling to produce the gut of the imago. It has been previously demonstrated that some bacterial species survive metamorphosis, being left behind in the puparium, present on the body surface, or in the gut of the emerged adult. We used a combined culture-molecular approach to identify viable microbes from managed manure residue and a wild population of house fly larvae, pupae, puparia, and adults to assess transstadial carriage. All larval (10/10), pupal (10/10), and puparial (10/10) cultures were positive for bacteria. Several bacterial species that were present in larvae also were present either in pupae or puparia. Four viable bacterial species were detectable in 6 of 10 imagoes reared from manure. Of note is the apparent transstadial carriage of Bacillus sonorensis, which has been associated with milk spoilage at dairies, and Alcaligenes faecalis, which can harbor numerous antibiotic resistance genes on farms. The potential of newly emerged flies to harbor and disseminate bacteria from managed manure on farms is an understudied risk that deserves further evaluation.

The “animalization” influence on the specific activity of a live plague vaccine in the model animal experiments

Objective: Assessment of the “animalization” impact on the immunogenicity and viability of EV live plague vaccine. Methods: In this research we have used a vaccine strain of Yersinia pestis EV (a RIEH line), and a strain 231 from the National Depository of highly dangerous microorganisms of the Kazakh Scientific Center of Quarantine and Zoonotic Diseases (KSCQZD). For the cultivation and evaluation of cultural, biochemical properties, as well as phage lysability of the vaccine strain we used Hottinger agar, Hottinger broth, peptone water with 1% glycerol, 1% sucrose, 1% lactose, 1% rhamnose and Andred indicator, a sterile 0.9% sodium chloride, and also plague diagnostic bacteriophages L-413 and Pokrovsky, produced in KSCQZD, and determination of the cell concentration using 10 units standard turbidity. We carried out “animalization” of the vaccine by its intravenous infusion to 5 rabbits weighting from 2 to 2.5 kg, with subsequent (after 3-4 hours) isolation of the vaccine strain culture from rabbit’s internal organs. We evaluated the protective activity in acute experiments of contamination of previously immunized guinea pigs weighing from 250 to 350 g (by a number of survived animals), and immunogenicity by ED50 value for all series of “animalized” and “not animalized” EV vaccine. The viability (percent of live cells) was determined by the number of colonies grown on Hottinger agar compared with the concentration of bacteria marked on an ampoule. As the percentage of viable microbial cells in a series, we accepted the arithmetic mean calculated for the three ampoules of the same series. Results: Indicators of the specific activity of the vaccine series prepared with the inclusion in the process of an “animalization” stage showed their significant growth. Significant increase in the number of surviving after contamination guinea pigs in combination with a significant reduction ED50 indicates that short stay of the vaccine strain in a rabbit body leads to a significant increase in protective activity (immunogenicity) of the finished vaccine. The number of viable cells in the final vaccine increases, too. Conclusions: Short-term (within 3-4 hours) stay of the 2nd generation culture during the process of a live plague vaccine production greatly enhances its immunogenicity (protective activity). The vaccine obtained with the inclusion in its production process of the “animalization” step contains a significantly greater number of viable microbes, as compared to conventional technology without “animalization”.