Identical Strains Research Articles

Characterization of host and escherichia coli strains causing recurrent urinary tract infections based on molecular typing

BackgroundEscherichia coli is the leading pathogen responsible for urinary tract infection (UTI) and recurrent UTI (RUTI). Few studies have dealt with the characterization of host and bacteria in RUTI caused by E. coli with genetically identical or different strains. This study aimed to investigate the host and bacterial characteristics of E. coli RUTI based on molecular typing.ResultsPatients aged 20 years or above who presented with symptoms of UTI in emergency department or outpatient clinics between August 2009 and December 2010 were enrolled. RUTI was defined as patients had 2 or more infections in 6 months or 3 or more in 12 months during the study period. Host factors (including age, gender, anatomical/functional defect, and immune dysfunction) and bacterial factors (including phylogenicity, virulence genes, and antimicrobial resistance) were included for analysis. There were 41 patients (41%) with 91 episodes of E. coli RUTI with highly related PFGE (HRPFGE) pattern (pattern similarity > 85%) and 58 (59%) patients with 137 episodes of E. coli RUTI with different molecular typing (DMT) pattern, respectively. There was a higher prevalence of phylogenetic group B2 and neuA and usp genes in HRPFGE group if the first episode of RUTI caused by HRPFGE E. coli strains and all episodes of RUTI caused by DMT E. coli strains were included for comparison. The uropathogenic E. coli (UPEC) strains in RUTI were more virulent in female gender, age < 20 years, neither anatomical/ functional defect nor immune dysfunction, and phylogenetic group B2. There were correlations among prior antibiotic therapy within 3 months and subsequent antimicrobial resistance in HRPFGE E. coli RUTI. The use of fluoroquinolones was more likely associated with subsequent antimicrobial resistance in most types of antibiotics.ConclusionsThis study demonstrated that the uropathogens in RUTI were more virulent in genetically highly-related E. coli strains. Higher bacterial virulence in young age group (< 20 years) and patients with neither anatomical/functional defect nor immune dysfunction suggests that virulent UPEC strains are needed for the development of RUTI in healthy populations. Prior antibiotic therapy, especially the fluoroquinolones, within 3 months could induce subsequent antimicrobial resistance in genetically highly-related E. coli RUTI.

First Report of Soft Rot Caused by Pectobacterium polaris on Lettuce in China.

Lettuce (Lactuca sativa) is a leafy vegetable that belongs to the family Asteraceae. It is widely cultivated and consumed around the world. In May 2022, lettuce plants (cv. 204) showing soft rot symptoms were observed in greenhouses in Fuhai District (25°18'N, 103°6'E), Kunming City, Yunnan Province, China. The disease incidence in three greenhouses (0.3 ha in size) was between 10% to 15%. The lower parts of the outer leaves showed brown and water-soaked symptoms, but at the same time the roots were asymptomatic. Sclerotinia species can cause soft decay on lettuce leaves, known as lettuce drop, which can produce symptoms partially resembling those of bacterial soft rot (Subbarao 1998). The absence of white mycelium or black sclerotia on the leaf surfaces of diseased plants indicated that Sclerotinia species were not responsible for the disease. Instead, it is more likely that bacterial pathogens were the cause. Fourteen diseased plants were sampled from three greenhouses, and potential pathogens were isolated from the leaf tissues of six plant individuals. Leaf samples were cut into pieces ca. 0.5 cm in length. The pieces were then surface-sterilized by dipping in 75% ethanol for 60 sec, followed by three successive rinses using sterile distilled water. The tissues were immersed in 250 µl of 0.9% saline in 2 mL microcentrifuge tubes and gently pressed down with grinding pestles for 10 sec. The tubes were let stand still for 20 min. Aliquots (20 μl) 100-fold dilutions of the tissue suspensions were plated onto Luria-Bertani (LB) plates and incubated at 28°C for 24 h. Three single colonies were picked from each LB plate and restreaked five times for purity. After purification, eighteen strains were obtained, and nine of these were identified by 16S rDNA sequencing using the universal primer pair 27F/1492R (Weisburg et al. 1991). Six out of nine strains (6/9) belonged to the genus Pectobacterium (OP968950-OP968952, OQ568892- OQ568894), two strains (2/9) belonged to the genus Pantoea (OQ568895 and OQ568896), and one strain (1/9) belonged to Pseudomonas sp. (OQ568897). Since the Pectobacterium strains shared identical 16S rDNA sequence, strains CM22112 (OP968950), CM22113 (OP968951) and CM22132 (OP968952) were selected as representative strains for further testing. The 16S rDNA sequences of Pectobacterium strains were 100% identical to that of the P. polaris strain NIBIO 1392 (NR_159086.1). To identify the strains to the species level, multilocus sequence analysis (MLSA) was performed using sequences of six housekeeping genes acnA, gapA, icdA, mdh, proA and rpoS (OP972517-OP972534) (Ma et al. 2007; Waleron et al. 2008). Phylogenetic analysis showed that the strains clustered with P. polaris type strain NIBIO1006T (Dees et al. 2017). They were all capable of utilizing citrate, which is an important biochemical feature in distinguishing P. polaris from its most closely related sister species P. parvum (Pasanen et al. 2020). Lettuce plants (cv. 204), at the rosette stage, were inoculated with the strains CM22112 and CM22132 by injecting 100 µl of bacterial suspensions (107 CFU·mL-1) into the lower parts of the leaf; for the controls, 100 µl of saline was used instead. Inoculated plants were incubated at room temperature (23°C) and 90% relative humidity. Five days after inoculation, only the bacteria-inoculated lettuce showed severe soft rot symptoms. Similar results were observed in two independent experiments. Bacterial colonies were obtained from the infected lettuce leaves, which showed identical sequences to P. polaris strains CM22112 and CM22132. Therefore, these strains fulfilled Koch's postulates for lettuce soft rot. P. polaris is prevalent on potato in many countries (Dees et al. 2017). To our knowledge, this is the first report of P. polaris causing soft rot on lettuce in China. This disease could seriously affect the appearance and saleability of lettuce. Further research on the epidemiology and management strategies of the disease is needed.

Incongruous identities: Mental distress and burnout disparities in LGBTQ+ health care professional populations

Health care professionals are chronically overworked due to structural workplace demands and institutional challenges [1]. During the COVID-19 pandemic, US biomedical health care professionals experienced additional environmental strain [2]. Health care professionals who occupy socio-politically minoritized identities are more likely to report symptoms of distress and workplace overburden than their counterparts [2]. While minority stress and identity formation theories explain the relationship between socially constructed identity and environmental strain, these theories remain largely unexplored in LGBTQ+ health care professional populations. Furthermore, contemporary investigations into health care professional burnout and mental distress fail to include differential impacts of identity-based stress, particularly within LGBTQ+ groups. This paper proposes a theoretical explanation for differential stress experiences by health care professionals and calls for research to investigate identity congruence as a key aspect of professionalization in medical schools. Health professions researchers need to attend to identity-based stress models to address discriminatory experiences with burnout and mental distress.

Health care-associated measles outbreak in pediatric wards in a tertiary care hospital: Challenges and Swiss cheese model enforcement for patient safety

IntroductionMeasles is one of the most contagious of all infectious diseases, for example, up to 9 out of 10 susceptible people with close contact to a measles patient will develop measles. In countries where measles is rare, transmissions in health care facilities have been a key factor in amplifying outbreaks ObjectivesDescribe the hospital transmission of measles among unvaccinated children in pediatric service, challenges faced and recommendations for health care settings by applying the Swiss cheese model. MethodBetween December 2019 and January 2020; multiple exposures to measles cases occurred. The incident and factors that led to the outbreak are described. The matrix and fusion genes, non-coding region sequence analysis was also conducted on the 3 strains isolated from the cases. ResultsThe outbreak extended from December 2019 to January 2020, which resulted in 110 exposed individuals (85 health care workers and 25 patients). Eleven (44%) children exposed were vaccinated, 14 (56%) were not yet vaccinated, and the measles status of 10 (11.8%) HCWs was not known at the time of the outbreak. Two infants acquired measles in the hospital, and both required ICU care. Three infants and one HCW received immunoglobulin. The phylogenetic tree of the matrix and fusion genes, non-coding region sequencing confirmed that all three cases had 100% identical measles strain. ConclusionsIn countries where measles elimination goals are achieved, a multifaceted approach to prevent measles transmission in health care is vital to maintain patient safety.

Phenotypic and genotypic characterization of antibiotic resistance of Salmonella Heidelberg in the south of Brazil

Salmonella is the main human pathogen present in the poultry chain. Salmonella Heidelberg is one of the most important serovars for public health since it has been frequently isolated in broiler chickens from different countries and may present multidrug resistance (MDR). This study was carried out with 130 S. Heidelberg isolates collected from pre-slaughter broiler farms in 2019 and 2020 in 18 cities from three Brazilian states to study relevant aspects regarding their genotypic and phenotypic resistance. The isolates were tested and identified using somatic and flagellar antiserum (0:4, H:2, and H:r), and an antimicrobial susceptibility test (AST) was performed against 11 antibiotics for veterinary use. The strains were typed by Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR, and representatives of the main clusters of the identified profiles were sequenced by Whole Genome Sequencing (WGS). AST results showed that all isolates were resistant to sulfonamide, 54 % (70/130) were resistant to amoxicillin, and only one was sensitive to tetracycline. Twelve isolates (15.4 %) were MDR. The dendrogram obtained from the ERIC-PCR showed that the strains were grouped into 27 clusters with similarity above 90 %, with some isolates showing 100 % similarity but with different phenotypic profiles of antimicrobial resistance. Identical strains collected on the same farm on other dates were identified, indicating that they were residents. WGS identified 66 antibiotic-resistance genes. The sul2 (present in all sequenced samples) and tet(A) genes were highlighted and validated in the experimental analysis. The fosA7 gene was also identified in all sequenced samples, but resistance was not observed in the phenotypic test, possibly due to the heteroresistance of the S. Heidelberg strains evaluated. Considering that chicken meat is one of the most consumed meats in the world, the data obtained in the present study can corroborate the mapping of the origin and trends of antimicrobial resistance.

Recurrent bloodstream infections after allogeneic hematopoietic cell transplantation

ABSTRACT Background Although colonization is an established risk factor for bloodstream infection (BSI) due to identical strain, prior infection with resistant bacteria should also be considered during the management of febrile neutropenia. This study aimed to analyze the rate and etiology of recurrent BSI in allogeneic hematopoietic cell transplant (allo-HCT) recipients to determine its potential impact on decision-making. Materials and methods The retrospective study included 284 allo-HCT recipients. Recurrent BSI was defined as a new BSI episode occurring in a period of more than 72 hours after antibiotic withdrawal. Results Overall, 104 patients (36.6%) developed at least one BSI, and 23 of them (22.1%) experienced recurrent BSI episodes (n = 30). Median time to recurrent BSI was 41 days (range 5–526 days). Recurrent BSI was associated with second allo-HCT (p < 0.0001), primary (p = 0.021), and secondary graft failure (p = 0.024). Carbapenem-resistant gram-negative bacteria were more common during recurrent BSI episodes (23.7% vs. 6.0%; p = 0.003). In only 17.5% patients experiencing recurrent BSI episode and in only 3.9% of patients with at least one BSI episode phenotypically identical recurring pathogen was isolated. Conclusions In view of low rate of recurrent BSI due to identical pathogen, empirical antimicrobial therapy should not be based on data on previous BSI episodes.

Random Amplified Polymorphic DNA for identical Streptococcus salivarius strains isolated from tongue of peoples before and after Listerine In vivo

Random Amplified Polymorphic DNA for identical Streptococcus salivarius strains isolated from tongue of peoples before and after Listerine In vivo

Effect of pile orientation on the fatigue performance of jointless bridge H-piles subjected to cyclic flexural strains

This paper explores the effect of pile orientation on the low cycle fatigue (LCF) performance of steel H–piles (SPs) at jointless bridge (JB) abutments via experimental testing and finite element simulation. The experimental testing program includes 42 full scale SP specimens subjected to strong axis (SA) and weak axis (WA) bending. The SPs are tested under cyclic displacement reversals mimicking the thermal induced displacement cycles associated with the seasonal elongation and contraction of the JB in the summer and winter times. The magnitude of the axial load is also kept as a variable in the experimental testing program to investigate its effect on the cyclic performance of JB SPs. The test results are then verified via finite element simulation and a parametric numerical study is performed to further understand the cyclic behavior of SPs as a function of numerous parameters. The tests and numerical analyses results revealed that for identical cyclic flexural strain amplitudes, SPs oriented for WA bending generally demonstrate a superior performance in terms of LCF life in the presence of axial loads compared to those oriented for SA bending. Moreover, the research results showed that at large flexural strains, local buckling becomes more critical than the pile orientation for the LCF life of SPs in JBs.

Study on the Mechanical Properties of Natural Gas Hydrate Reservoirs with Multicomponent under Different Engineering Conditions

For wellbore stability issues induced by drilling operations in natural gas hydrate-containing reservoirs, wellbore stability research will focus on the mechanical properties of hydrate reservoirs. According to the content of the research, the response relationship between the hydrate core and the base physical property changes under different engineering parameters is established, and the law of hydrate mechanical property changes with temperature and pressure is studied for various physical properties. According to theoretical research and experimental data, it has been determined that: hydrate core-resolved gas and transverse and longitudinal wave velocity have a positive correlation with saturation and pressure and a negative correlation with temperature; a negative correlation exists between resistivity and saturation. The hydrate core stiffness strength correlates positively with saturation and adversely with temperature. Under the identical strain conditions, when saturation, pore pressure, and temperature increase, the stress of the hydrate grows rapidly; there is a distinct inflection point, and the hydrate does not form above a particular temperature. To prevent the decomposition of hydrates and minimize disasters such as well wall instability and reservoir collapse, it is possible to reduce reservoir in situ temperature and pressure fluctuations in accordance with operational requirements.

Hot deformation behavior of a novel alpha + beta titanium alloy TIMETAL®407

The hot deformation behavior of a newly developed α + β titanium alloy TIMETAL®407 (Ti407) was characterized in starting transformed-β microstructure at different temperatures (T = 650–950 °C) and strain rates (ε̇ = 10−3 - 1 s−1) using hot-compression testing. The Arrhenius type constitutive equations are developed for Ti407 and the activation energy for deformation is determined as 333.1 and 179.8 kJ/mol in the α and β dominated phases, respectively. The processing and strain-rate sensitivity maps of Ti407 were generated at true strain, ε = 0.5 on the basis of modified dynamic materials model (DMM) proposed by Murty and Rao. Results obtained from the maps and microstructural analysis of the deformed specimens indicates three distinct stable domains (I-A, II-A and I-B) within the examined conditions. Out of the three stable domains, Domain I-A occurring in the α + β phase field (T = 800–860 °C and ε̇= 6.3 ×10−2 - 1 s−1) and Domain I-B in the β phase field (T = 900–950 °C and ε̇= 10−3 - 1 s−1) were optimum domains for possible hot working of Ti407. The peak in the efficiency of power dissipation of about 58% occurred in Domain I-A at 850 °C/1 s−1, where dynamic spherodization of α lamellae occurred. In Domain I-B, formation of fine dynamically recrystallized β grains was observed with peak in power dissipation efficiency of about 60% at 950 °C/10−3 s−1. Ti407 showed evidence of flow instabilities like flow localization and kinking of α lamellae in the predicted unstable zones identified from the processing map. The hot workability of Ti407 on the basis of expanding or shrinking stable regimes for processing is also compared with CP-Ti and Ti-6Al-4V alloys at identical strain rates and temperatures relative to the beta-transus. Finite element method (FEM) software DEFORM®− 3D was used for forging simulation at the peak in deformation efficiency condition in various stable domains to evaluate the flow response and distributions of stress/strain in the forged billets.

An anchored experimental design and meta-analysis approach to address batch effects in large-scale metabolomics.

Untargeted metabolomics studies are unbiased but identifying the same feature across studies is complicated by environmental variation, batch effects, and instrument variability. Ideally, several studies that assay the same set of metabolic features would be used to select recurring features to pursue for identification. Here, we developed an anchored experimental design. This generalizable approach enabled us to integrate three genetic studies consisting of 14 test strains of Caenorhabditis elegans prior to the compound identification process. An anchor strain, PD1074, was included in every sample collection, resulting in a large set of biological replicates of a genetically identical strain that anchored each study. This enables us to estimate treatment effects within each batch and apply straightforward meta-analytic approaches to combine treatment effects across batches without the need for estimation of batch effects and complex normalization strategies. We collected 104 test samples for three genetic studies across six batches to produce five analytical datasets from two complementary technologies commonly used in untargeted metabolomics. Here, we use the model system C. elegans to demonstrate that an augmented design combined with experimental blocks and other metabolomic QC approaches can be used to anchor studies and enable comparisons of stable spectral features across time without the need for compound identification. This approach is generalizable to systems where the same genotype can be assayed in multiple environments and provides biologically relevant features for downstream compound identification efforts. All methods are included in the newest release of the publicly available SECIMTools based on the open-source Galaxy platform.

γ″ variant-sensitive deformation behaviour of Inconel 718 superalloy

• This study reveals, for the first time, the micro-mechanism of deformation of γ″ strengthened superalloys using neutron diffraction. • Inconel 718 samples with different γ″ variant distributions were prepared by different stress ageing heat treatments. • The γ″ variant-sensitive deformation behavior was studied by interpreting the stress-lattice strain curves. • Compressive-aged sample shows larger yield strength compared to the tensile-aged sample • The difference in strengthening arises from the interactions between dislocations and different γ″ variants. Strengthening in Inconel 718 superalloy is derived from dislocation interaction with γ″ precipitates, which exist in disk-shaped three possible orientation variants with their {100} habit plane normal to each other. The interactions between dislocations and γ″ precipitates vary according to the γ″ orientation variants, which makes the deformation behaviour complicated and difficult to reveal experimentally. In this work, γ″ variant distributions of Inconel 718 samples were tailored by ageing heat treatment under either tensile or compressive stress. The γ″ variant-sensitive deformation behaviours were then studied by in situ tensile tests via neutron diffraction at room temperature. It is demonstrated that yielding first takes place in grains oriented with <110> parallel to the loading direction. An identical lattice strain response to applied stress of both the γ matrix and the γ″ precipitates was observed during yielding, suggesting that dislocations shearing through the γ″ precipitates is predominant at this stage. Variations in yield strength for samples with different γ″ variant distributions were observed, which can be attributed to different strengthening that arises from interactions between dislocation and different γ″ variants.

SIE identity strain, job embeddedness and expatriate outcomes: within-domain and spillover buffering effects of off-the-job relationship building

Self-initiative expatriates (SIEs) are increasingly important to the global talent pool. However, they are vulnerable to identity strain due to their self-initiative status and tendency to maintain their previous identity during temporary stays in the host country. Drawing on conservation of resources theory, we establish a resource-based model to examine the indirect effects of SIEs’ identity strain on expatriate outcomes (performance, work withdrawal, repatriation intention) through on-the-job and off-the-job embeddedness, with off-the-job relationship building as the boundary condition. With a two-wave research design, we collected data from 103 Chinese visiting scholars at 48 American universities in 2017. The results show that identity strain has indirect effects on all three expatriate outcomes through on-the-job embeddedness and an indirect effect on repatriation intention through off-the-job embeddedness. Off-the-job relationship building buffers the indirect effects of identity strain on expatriate outcomes via on-the-job embeddedness rather than off-the-job embeddedness.

Control of Acinetobacter baumannii outbreak in intensive care units in Tunisia, 2022

Abstract Introduction Acinetobacter baumannii is an emerging pathogen that is increasingly resistant to antibiotics and is mainly responsible for pneumopathy in fragile patients. This germ is frequently responsible for epidemics in hospitals. We aimed to describe the steps of the investigation of an outbreak of Acinetobacter baumannii affected our hospital, the measures implemented and the follow-up of the actions. Methods Following alerts issued by the microbiology department concerning 5 swabs detecting Acinetobacter of the same strain and the same antibiotic resistance profile in 3 different departments of intensive-care units (ICU), a team of the prevention and healthcare security department went onsite for an investigation in the hospital. Results We identified five cases with identical strains of multi-resistant Acinétobacter. The field visit allowed to identify some deficiencies in professional practices. All the patients were hospitalized in ICU (medical and surgical). The synoptic table showed that there was an overlap of hospitalization periods.A crisis cell was set up to validate, coordinate and implement control measures in accordance with CTINILS recommendations. Indeed, we proceeded to a technical isolation of the cases in their hospitalization sector, reinforced the basic hygiene and bio-cleaning measures and sensitized the medical and paramedical. Given that the three ICU departments shared the same medical staff during night shifts, the assumption that the germ was carried by the caregivers was the most likely hypothesis. We proceeded with a swab of the elements of the environment in the services concerned. Results showed that Acinetobacter was found on the nursing cart (visibly clean). A training about bio-cleaning and hygiene standard precautions is programmed. Conclusions Continuous surveillance, continuous hygiene trainings, combined with a rapid reaction capacity in case of identification of a new case, is essential to control the spread of nosocomial germs. Key messages • Multidrug-resistant Acinetobacter baumannii (MRAB) is an emerging cause of intensive care unit (ICU) outbreaks. • Enhanced infection control measures limited the outbreak.

THE USE OF MOLECULAR GENETIC METHODS BASED ON MLVA ANALYSIS TO CONFIRM THE UNIQUENESS OF COLLECTION STRAINS OF BRUCELLA

Collections of pathogenic bacterial cultures are necessary for the storage of commercially valuable and typical strains for the purpose of patenting, production and testing of diagnostic and preventive drugs, as well as epidemiological strains isolated during the diagnosis of infectious diseases for detailed study and monitoring of changes in sanitary and epidemiological well-being. Collections are replenished with new unique strains, so it is very important that the characteristics of these strains should be carried out using highly discriminatory molecular genetic methods. This article presents the results of the evaluation of the genetic diversity of 36 collection strains of Brucella abortus and 57 strains of Brucella melitensis by the Multilocus variable number tandem repeat (VNTR) analysis (MLVA-16). Generic identification and absence of contamination by other bacterial species was confirmed by sequencing of the 16S rRNA gene. MLVA analysis allowed to establish contamination of 4 strains with different genotypes of brucella and to reveal that the deposited 36 strains isolated in 14 outbreaks of brucellosis are identical genotypes of the pathogen. Our studies have confirmed the presence of identical brucella strains in the collection. The use of MLVA-16 in testing isolated bacterial cultures from a single outbreak will allow differentiating unique strains for their subsequent deposition. Verification of deposited strains with MLVA characteristics with a detailed analysis of metadata about deposited strains will optimize the collection, in terms of preserving only unique strains, which will reduce economic costs and risks to ensure biological safety.

Seroprevalence and genotype distribution of hepatitis A virus in the pre-vaccine era in South Transdanubia, Hungary (2010-2020).

In this study, the age-related seroprevalence of hepatitis A virus (HAV) infection was investigated in the population in South-Transdanubia, Southwest Hungary (Central Europe) between years 2010 and 2020. Up to the age of 40, the HAV seropositivity was less than 18% in all age groups indicating a low level of HAV endemicity in this part of the country in the covered study period. The HAV seropositivity started to increase at the age group 41-45 years, reaching the ∼50% at age group 56-60, and 75-80% at age group 66-70, respectively. A total of 43 (0.2%) of the 21,106 tested sera were HAV IgM-positive (the annual percentage range of HAV IgM-positivity was 0.046-0.6%). Total of 24 (55.8%) of the 43 HAV IgM-positive samples tested RT-PCR-positive confirmed as HAV sub-genotypes IA (N = 17; 70.8%) and IB (N = 7; 29.2%), respectively. Imported HAV infections (three cases from Romania, and one-one case from Austria and Italy), two small outbreaks and 11 cases of a genetically identical sub-genotype IA strain (GenBank number of the prototype strain: KM657825) from 2012 to 2014 were identified later connected directly to the enormous HAV outbreak initiated among men who have sex with men (MSM) at the end of 2011 in the capital Budapest.In summary, low endemicity but high and increased susceptibility for HAV infection was found in the population in Southwest Hungary, where repeated introduction of sub-genotypes IA and IB HAV strains were identified between 2010 and 2020.

Extensive diversity and rapid turnover of phage defense repertoires in cheese-associated bacterial communities

BackgroundPhages are key drivers of genomic diversity in bacterial populations as they impose strong selective pressure on the evolution of bacterial defense mechanisms across closely related strains. The pan-immunity model suggests that such diversity is maintained because the effective immune system of a bacterial species is the one distributed across all strains present in the community. However, only few studies have analyzed the distribution of bacterial defense systems at the community-level, mostly focusing on CRISPR and comparing samples from complex environments. Here, we studied 2778 bacterial genomes and 188 metagenomes from cheese-associated communities, which are dominated by a few bacterial taxa and occur in relatively stable environments.ResultsWe corroborate previous laboratory findings that in cheese-associated communities nearly identical strains contain diverse and highly variable arsenals of innate and adaptive (i.e., CRISPR-Cas) immunity systems suggesting rapid turnover. CRISPR spacer abundance correlated with the abundance of matching target sequences across the metagenomes providing evidence that the identified defense repertoires are functional and under selection. While these characteristics align with the pan-immunity model, the detected CRISPR spacers only covered a subset of the phages previously identified in cheese, providing evidence that CRISPR does not enable complete immunity against all phages, and that the innate immune mechanisms may have complementary roles.ConclusionsOur findings show that the evolution of bacterial defense mechanisms is a highly dynamic process and highlight that experimentally tractable, low complexity communities such as those found in cheese, can help to understand ecological and molecular processes underlying phage-defense system relationships. These findings can have implications for the design of robust synthetic communities used in biotechnology and the food industry.DbLYqYwr-FU-DxBRk3MVnLVideo

Genetic identification and comparative study on life history parameters of two strains belonging to Brachionus plicatilis species complex (Rotifera: Monogononta)

The rotifer Brachionus plicatilis is an important species for aquaculture, due to its use as food for bivalves, and fish and crustaceans larvae in hatcheries. However, being a species complex, it has become increasingly important to catalogue and describe the species and biotypes that constitute this complex. Therefore, the purpose of this study was to genetically identify two morphologically identical strains and evaluate their suitability to be used in aquaculture under the studied conditions. A correct identification and knowledge of life history characteristics of the biotypes and isolated strains is vital to avoid mass mortalities in aquaculture and to better interpret the responses of the organisms when these are used as a bioindicator and model for ecotoxicology. Strains MRS10 and IBA3 were identified as B. koreanus and, even though they have been maintained under the same laboratory conditions for several years, significant differences in several life history parameters were observed. A life table assay showed IBA3 rotifers to be larger at first reproduction, and to have longer post-reproductive period and mean lifespan. On the other hand, MRS10 rotifers produced less non-viable eggs and had higher population growth rate. Both strains showed to be a potential model for ecotoxicological and molecular studies, mainly due to the ease of maintenance, short generation time, and reproduction via parthenogenesis. However, MRS10 might present better characteristics than IBA3 to be reared in aquaculture as live food.

Repatriates’ Experience of Identity Strain and Repatriate Knowledge Transfer

While it is common for repatriates to experience identity strain when they return from an international assignment, we know little about how the experience of strain leads to knowledge-related outcomes for repatriates and, by extension, their coworkers. Adopting an identity theory perspective, we conceptualize knowledge transfer as a form of repatriates’ identity enactment in the face of identity strain upon their return. Further, we consider two conditions that determine how repatriates’ experience of identity strain may translate into beneficial knowledge transfer outcomes for repatriates’ colleagues: repatriates’ generalized self-efficacy and colleagues’ trust in repatriates. Drawing on a sample of 118 matched repatriate-colleague responses across five MNCs, we find that repatriates’ level of knowledge transfer with colleagues mediates the relationship between repatriates’ identity strain and colleague perceptions of useful knowledge receipt from repatriates. We also demonstrate that while this mediated relationship is negative at low levels of repatriates’ generalized self-efficacy, it becomes non-significant when generalized self-efficacy is high. Similarly, the mediated relationship is negative at low levels of colleagues’ trust in repatriates, but non-significant at high levels of colleagues’ trust in repatriates. Our study contributes to identity theory and the literatures on international assignments and knowledge transfer in MNCs.

Employee Experiences Across Their Multiple Teams: New Theoretical Directions in MTM Research

There are indicators we are entering a new era for MTM research, by moving beyond the structural approach that has characterized MTM research to date, to focus on important and under-researched issues, such as the nature of employees’ experiences in an MTM context. Although team research suggests that the experiences of members impact team functioning, these lines of reasoning have not, until recently, made their way to MTM research. To overcome this limitation, this symposium showcases five papers that use a variety of theoretical perspectives, research designs, contexts, methodologies, and analytical methods (i.e., archival, field-based, laboratory) to extend theory and examine critical individual and firm-level outcomes (e.g., firm performance, individual proactivity, individual learning, individual turnover, and individual career-related outcomes) in the experiences of MTM employees across their teams (e.g., identification, learning, etc.). We hope to provide a forum to advance unanswered questions that offer fruitful directions for MTM research. Together Alone? The Benefits and Downsides of Flexible Team Arrangements Presenter: Stefan Berger; U. of Groningen Status Dynamics in MTM Context: Implication for Employees' Identification and Proactivity Choices Presenter: Yehuda Salhov; Bar Ilan U. Many Teams, One Better Career? A Study on the Impact of MTM on Individual Career Trajectories Presenter: Francesca Bellesia; Dep. of Sciences and Methods for Engineering, U. of Modena and Reggio Emilia Multiple Team Membership and Learning: The Mediating Role of Knowledge Hiding Presenter: Oana Fodor; Babes-Bolyai U. Examining the Impact of MTM Identity Strain and Emotional Control on Cognitive Depletion & Turnover Presenter: Sal Mistry; U. of Delaware