Ab Strains Research Articles

High mortality of Acinetobacter baumannii infection is attributed to macrophage-mediated induction of cytokine storm but preventable by naproxen

The continuous emergence of multidrug-resistant (MDR) Acinetobacter baumannii (Ab) strains poses further challenges in its control and clinical management. It is necessary to decipher the mechanisms underlying the high mortality of Ab infections to explore unconventional strategies for controlling outbreaks of drug-resistant infections. The immune responses of Ab sepsis infection were investigated using flow cytometry, RNA-seq, qRT-PCR, and ELISA and scRNA-seq. The detailed pathways mediating Ab immune responses were also depicted and a specific therapy was developed based on the understanding of the mechanisms underlying Ab-induced cytokine storms. The results highlighted the critical role of alveolar and interstitial macrophages as targets of Ab during the infection process. These cells were found to undergo polarization towards the M1 phenotype, triggering a cytokine storm that eventually caused the death of the host. The polarization and excessive inflammatory response mediated by macrophages were mainly regulated by the TLR2/Myd88/NF-κB signaling pathway. Suppression of Ab-triggered inflammatory responses and M1 polarization by the drug naproxen (NPXS) was shown to confer full protection of mice from lethal infections. The findings in this work depict the major mechanisms underlying the high mortality rate of Ab infections and highlight the clinical potential application of anti-inflammatory drugs or immunosuppressants in reducing the mortality of such infections, including those caused by MDR strains. Funding sources are described in the acknowledgments section.

Erythromycin disrupts Acinetobacter baumannii biofilms through destruction of the quorum sensing system.

This study was conducted to explore the effects of erythromycin on biofilms comprising Acinetobacter baumannii (A baumannii). To clarify the effect of erythromycin on the biofilms of A baumannii, we collected pure Ab strains isolated and identified from a variety of sample types extracted from patients in the microbiological laboratory of our hospital from April to August 2023, and divided them into an experimental group (treated with erythromycin) and a control group (without erythromycin). The morphology and quantity of A baumannii biofilm were observed at 24h, 48h, 72h, and 5d post-treatment, respectively, and the expression of quorum sensing (QS) system gene (abaI, abaR) mRNA was detected by fluorescence quantitative PCR. The results showed that A baumanniis are prone to form multiple drug-resistant (MDR) bacteria, against which the most commonly used clinical antibiotics are ineffective. Overall, we found that the number of bacteria, the number of bacteria in the biofilm, and the number of biofilms formed gradually increased over time, with a statistical difference (P < .05). After the addition of erythromycin, significant improvements in biofilm formation were achieved, indicating that erythromycin can destroy A baumannii biofilms, inhibiting bacterial growth to a certain extent. The expression levels of abaI and abaR gradually increased over time, indicating that the role of the QS system became more apparent over time. Biofilm formation is related to the QS system of A baumanniis. After erythromycin treatment, abaI and abaR mRNA expression was downregulated in the experimental group. Erythromycin disrupts A baumannii biofilms by destroying the quorum sensing system.

Phenotypic Investigation and Detection of Biofilm-Associated Genes in Acinetobacter baumannii Isolates, Obtained from Companion Animals.

Bacteria of the genus Acinetobacter, especially Acinetobacter baumannii (Ab), have emerged as pathogens of companion animals during the last two decades and are commonly associated with hospitalization and multidrug resistance. A critical factor for the distribution of relevant strains in healthcare facilities, including veterinary facilities, is their adherence to both biotic and abiotic surfaces and the production of biofilms. A group of 41 A. baumannii isolates obtained from canine and feline clinical samples in Greece was subjected to phenotypic investigation of their ability to produce biofilms using the tissue culture plate (TCP) method. All of them (100%) produced biofilms, while 23 isolates (56.1%) were classified as strong producers, 11 (26.8%) as moderate producers, and 7 (17.1%) as weak producers. A correlation between the MDR and XDR phenotypes and weak or moderate biofilm production was identified. Moreover, the presence of four biofilm-associated genes bap, blaPER, ompA, and csuE was examined by PCR, and they were detected in 100%, 65.9%, 97.6%, and 95.1% of the strains respectively. All isolates carried at least two of the investigated genes, whereas most of the strong biofilm producers carried all four genes. In conclusion, the spread and persistence of biofilm-producing Ab strains in veterinary facilities is a matter of concern, since they are regularly obtained from infected animals, indicating their potential as challenging pathogens for veterinarians due to multidrug resistance and tolerance in conventional eradication measures. Furthermore, considering that companion animals can act as reservoirs of relevant strains, public health concerns emerge.

Comparison of baseline cataract rates in AB and TL wildtype zebrafish strains

Zebrafish are an outstanding model for assessing the involvement of genes in paediatric cataracts. Gene discovery for cataracts is enhanced by manipulation of the genome of zebrafish embryos and comparing the phenotypes of mutant progeny with the wildtype embryos. However, wildtype laboratory fish can also develop cataracts, potentially confounding the results. In this study, we compared the baseline cataract rate between two commonly used wildtype laboratory strains, AB and TL, and also an outbred transgenic line with mCherry reporter. We assessed a total of 805 lens images of fish at 4 days post-fertilisation for cataracts and scored each cataract observed as mild, moderate or severe. We found that the AB strain had a cataract rate of 16.2%, TL had 8.9%, and mCherry had 0.7% and these rates were significantly different. We found that TL strain had a lower rate of mild cataracts than AB fish, however, the rate of moderate and severe phenotypes in the AB and the TL strain was similar. Overall, we showed that the baseline cataract rate varies significantly between the strains housed in a single facility and conclude that baseline rates of cataracts should be assessed when planning experiments to assess the genetic causes of cataracts.

Establishment of a zebrafish inbred strain, M-AB, capable of regular breeding and genetic manipulation

Inbred strains of organisms are genetically highly uniform and thus useful for life science research. We have previously reported the ongoing generation of the zebrafish IM strain from the India (IND) strain through full sib-pair mating for 16 generations. However, the IM fish laid a small number of offspring and had a short lifespan, implying the need for discreet care in breeding. Here, we report the subsequent establishment of IM strain as well as the generation of a new inbred zebrafish strain, Mishima-AB (M-AB). M-AB was derived from the *AB strain by full sib-pair mating for over 20 generations, which fulfills the general criterion for the establishment of an inbred strain. In contrast to the IM case, maintenance of the M-AB strain by sib-pair mating required almost no special handling. Genome sequencing of IM individuals from the 47th generation and M-AB individuals from the 27th generation revealed that SNP-based genomic heterogeneity across whole-genome nucleotides was 0.008% and 0.011%, respectively. These percentages were much lower than those of the parental IND (0.197%) and *AB (0.086%) strains. These results indicate that the genomes of these inbred strains were highly homogenous. We also demonstrated the successful microinjection of antisense morpholinos, CRISPR/Cas9, and foreign genes into M-AB embryos at the 1-cell stage. Overall, we report the establishment of a zebrafish inbred strain, M-AB, which is capable of regular breeding and genetic manipulation. This strain will be useful for the analysis of genetically susceptible phenotypes such as behaviors, microbiome features and drug susceptibility.

Azospirilla and Nitrogen Fertilization to Promote Maize Seed Development and Yield

Aims: This study evaluated the interaction of Azospirillum brasilense (Ab) strains and nitrogen fertilizer doses on maize.&#x0D; Study Design: Laboratory experiment evaluated Ab strains (PCR and PTF) on maize seed germination and vigor (completely randomized design). Field experiment evaluated Ab strains and nitrogen fertilization on maize yield parameters (randomized block design).&#x0D; Place and Duration of Study: The germination and vigor experiment (10 days in April 2019) was implemented in a controlled environment at the Seed Analysis Laboratory of the Universidade Federal de Uberlândia, Brazil. The field experiment (137 days in winter 2019) was implemented at the Fisioplant Research Station (Uberlândia, Brazil) under commercial maize crop management.&#x0D; Methodology: In controlled conditions (laboratory), 200 seeds of maize (K9105VIP3, Riber KWS Seeds) were incubated (25 °C) with the Ab strain solutions for germination and vigor evaluations. In the field, 60,000 plants ha-1 (0.5 m space between sowing lines) of maize were cropped under combinations of nitrogen fertilizer and volumes of Ab strains (treatments) for leaf nitrogen, SPAD index, leaf count, fresh and dry maize shoot biomass, one-thousand grains weight, grain rows per maize ear, productivity (kg ha-1).&#x0D; Results: Treatment with 100 mL ha-1 of Ab PFT strain increased maize seed germination and vigor more than Ab PCR strain and control (no-inoculation or fertilizer). The number of grain rows of the 100% N + 150 mL ha-1 of Ab PFT strain and the maize shoot dry mass of the 100% N (no-inoculation) were higher than the control. The treatments did not affect the SPAD index, weight of one thousand grains, fresh maize shoot biomass, or productivity.&#x0D; Conclusion: Using Ab with nitrogen fertilizer is a promising strategy to improve maize crop responses; however, more studies are needed to detail the ideal management of Ab strains for maize crops and yield construction.

Direct male development in chromosomally ZZ zebrafish.

The genetics of sex determination varies across taxa, sometimes even within a species. Major domesticated strains of zebrafish (Danio rerio), including AB and TU, lack a strong genetic sex determining locus, but strains more recently derived from nature, like Nadia (NA), possess a ZZ male/ZW female chromosomal sex-determination system. AB fish pass through a juvenile ovary stage, forming oocytes that survive in fish that become females but die in fish that become males. To understand mechanisms of gonad development in NA zebrafish, we studied histology and single cell transcriptomics in developing ZZ and ZW fish. ZW fish developed oocytes by 22 days post-fertilization (dpf) but ZZ fish directly formed testes, avoiding a juvenile ovary phase. Gonads of some ZW and WW fish, however, developed oocytes that died as the gonad became a testis, mimicking AB fish, suggesting that the gynogenetically derived AB strain is chromosomally WW. Single-cell RNA-seq of 19dpf gonads showed similar cell types in ZZ and ZW fish, including germ cells, precursors of gonadal support cells, steroidogenic cells, interstitial/stromal cells, and immune cells, consistent with a bipotential juvenile gonad. In contrast, scRNA-seq of 30dpf gonads revealed that cells in ZZ gonads had transcriptomes characteristic of testicular Sertoli, Leydig, and germ cells while ZW gonads had granulosa cells, theca cells, and developing oocytes. Hematopoietic and vascular cells were similar in both sex genotypes. These results show that juvenile NA zebrafish initially develop a bipotential gonad; that a factor on the NA W chromosome, or fewer than two Z chromosomes, is essential to initiate oocyte development; and without the W factor, or with two Z doses, NA gonads develop directly into testes without passing through the juvenile ovary stage. Sex determination in AB and TU strains mimics NA ZW and WW zebrafish, suggesting loss of the Z chromosome during domestication. Genetic analysis of the NA strain will facilitate our understanding of the evolution of sex determination mechanisms.

The synergic and addictive activity of biogenic silver nanoparticle associated with meropenem against carbapenem-resistant Acinetobacter baumannii.

Antibiotic management of infections caused by Acinetobacter baumannii often fails due to antibiotic resistance (especially to carbapenems) and biofilm-forming strains. Thus, the objective here was to evaluate in vitro the antibacterial and antibiofilm activity of biogenic silver nanoparticle (Bio-AgNP) combined with meropenem, against multidrug-resistant isolates of A. baumannii. In this study, A. baumannii ATCC® 19606™ and four carbapenem-resistant A. baumannii (Ab) strains were used. The antibacterial activity of Bio-AgNP and meropenem was evaluated through broth microdilution. The effect of the Bio-AgNP association with meropenem was determined by the checkboard method. Also, the time-kill assay and the integrity of the bacterial cell membrane were evaluated. Furthermore, the antibiofilm activity of Bio-AgNP and meropenem alone and in combination was determined. Bio-AgNP has antibacterial activity with minimum inhibitory concentration (MIC) and minimum bactericidal concentration ranging from 0.46 to 1.87 μg ml-1. The combination of Bio-AgNP and meropenem showed a synergistic and additive effect against Ab strains, and Bio-AgNP was able to reduce the MIC of meropenem from 4- to 8-fold. Considering the time-kill of the cell, meropenem and Bio-AgNP when used in combination reduced bacterial load to undetectable levels within 10 min to 24 h after treatment. Protein leakage was observed in all treatments evaluated. When combined, meropenem/Bio-AgNP presents biofilm inhibition for Ab2 isolate and ATCC® 19606™, with 21% and 19%, and disrupts the biofilm from 22% to 50%, respectively. The increase in nonviable cells in the biofilm can be observed after treatment with Bio-AgNP and meropenem in carbapenem-resistant A. baumannii strains. The combination of Bio-AgNP with meropenem can be a therapeutic option in the treatment of infections caused by carbapenem-resistant A. baumannii.

Биологические свойства штаммов L. helveticus

The biological properties of three strains of L. helvetcus were studied. All studied strains metabolize D-galactose. The L. helveticus AB strain utilizes D-glucose, D-fructose, N-acetylglucosamine, and D-trehalose; L. helveticus 20T — D-mannose, N-acetylglucosamine; L. helveticus H-9 — D-glucose, D-lactose, D-trehalose. All strains showed high β-galactosidase activity, as well as the activity of acid phosphatase, naphthol-AS-BI hydrolase, leucine arylamidase, and cystine arylamidase. For L. helveticus 20T and L. helveticus AB strains, valine arylamidase activity was found. All strains are sensitive to gentamicin, ampicillin, tetracycline, azithromycin, lincomycin, chloramphenicol. The data obtained indicate the safety of using strains as part of starter cultures and as producers of metabolite additives in terms of reducing the risk of spreading antibiotic resistance.

Performance, Haematology and Serum Biochemical Status of two Strains of Broiler Chicken Fed Ficus thonningii Leaf Powder and Vitamin C Supplemented Diets

Aims: To evaluate the effect of Ficus thonningii leaf powder (FTLP) and vitamin C supplemented diets on performance and haemato-biochemical status of two strains of broiler chickens.&#x0D; Methodology: Four hundred and eighty-one-day-old of Arbor acre (AB) and Cobb 500 (CO) broiler chicks were randomized to eight dietary treatments; diet 1 and 2 (Control), diets 3 and 4 (200mg/kg vitamin C inclusion), diets 5 and 6 (1% inclusion of FTLP) and (diets 7 and 8 (200mg/kg + 1% FTLP inclusions) for AB and CO strains respectively.&#x0D; Results: Result shows that feed intake, body weight gain and FCR were significant (P&lt;0.05) at the starter phase. Interaction between strains and vitamin C were also significant (P&lt;0.05) for body weight gain, FCR and feed intake. Vitamin C and FTLP supplementation significantly (P&lt;0.05) improved the erythrocytes count while the MCV, MCH, WBC and lymphocytes of birds fed diets 2 and 6 were significantly (P&lt;0.05) higher than the other diets. The dietary supplementation of vitamin C and FTLP shows that strain AB had a significantly (P&lt;0.05) higher erythrocytes count than CO strain while the CO showed significant (P&lt;0.05) improvement for the MCV and MCH. Vitamin C supplementation showed significant difference (P&lt;0.05) for the RBC and the interaction of vitamin C and FTLP significantly (P&lt;0.05) improved PCV, HB, MCV, MCH, WBC and lymphocytes. The interactive effect of vitamin C and FTLP significantly (P&lt;0.05) improved the total protein and albumin. Cholesterol and creatinine levels were significantly (P&lt;0.05) lowered by the inclusion of vitamin C and FTLP.&#x0D; Conclusion: As observed in this study, the inclusion of FTLP and vitamin C as a supplement in the diets of broiler chickens improved the performance, haematological indices and serum biochemical status of the tested birds.

Effects of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on reproductive and endocrine function in female zebrafish (Danio rerio)

BackgroundPolybrominated diphenyl ethers (PBDEs), a group of brominated flame retardants (BFRs), were reported exist extensively in various ecological environmental. Studies have indicated that PBDEs induce reproductive toxic effects on human health, but the mechanisms remain poorly understood. In this study, the adult female zebrafish were used to investigate the effects of 2, 2′, 4, 4′-tetrabromodiphenyl ether (BDE-47) on the reproductive endocrine system and its mechanism. MethodsFemale zebrafish (AB strains) were continuously exposed to BDE-47 at the concentrations of 0, 10, 50, 100 and 500 µg/L till 21 days. The morphology of ovary were stained and evaluated with hematoxylin-eosin (H&E), and levels of sex hormones including follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and 17β-estradiol (E2) and the biomarkers of oxidative stress such as superoxide dismutase (SOD) and malondialdehyde (MDA), were measured via ELISA. Subsequently, the expression of genes along the hypothalamic pituitary-gonad (HPG) and oxidative stress were determined using quantitative real-time PCR (qRT-PCR). ResultThe results showed that exposure to high level of BDE-47 reduced the index of condition factor (CF) and gonadosomatic index (GSI). Treatment with BDE-47 impaired the normal development and structure of oocytes in zebrafish ovary. Moreover, the steroid hormone of FSH, LH, T and E2 were significantly decreased in BDE-47 exposure group. A dose-dependent elevation in SOD activity and MDA levels were recorded. Meanwhile, the transcription level of cyp19a, cyp19b, fshβ, lhβ were up-regulated while the transcription of fshr, lhr, cyp17a, 17βhsd were down-regulated in the gonad of female adult zebrafish. ConclusionExposure to BDE-47 have detrimental impact on the development of ovary, decreasing sex hormone levels, inducing oxidative damage as well as altering HPG axis-related genes.

Temporo-spatial variations in resistance determinants and clonality of Acinetobacter baumannii and Pseudomonas aeruginosa strains from Romanian hospitals and wastewaters

BackgroundRomania is one of the European countries reporting very high antimicrobial resistance (AMR) rates and consumption of antimicrobials. We aimed to characterize the AMR profiles and clonality of 304 multi-drug resistant (MDR) Acinetobacter baumannii (Ab) and Pseudomonas aeruginosa (Pa) strains isolated during two consecutive years (2018 and 2019) from hospital settings, hospital collecting sewage tanks and the receiving wastewater treatment plants (WWTPs) located in the main geographical regions of Romania.MethodsThe strains were isolated on chromogenic media and identified by MALDI-TOF-MS. Antibiotic susceptibility testing and confirmation of ESBL- and CP- producing phenotypes and genotypes were performed. The genetic characterization also included horizontal gene transfer experiments, whole-genome sequencing (WGS), assembling, annotation and characterization.ResultsBoth clinical and aquatic isolates exhibited high MDR rates, especially the Ab strains isolated from nosocomial infections and hospital effluents. The phenotypic resistance profiles and MDR rates have largely varied by sampling point and geographic location. The highest MDR rates in the aquatic isolates were recorded in Galați WWTP, followed by Bucharest. The Ab strains harbored mostly blaOXA-23, blaOXA-24, blaSHV, blaTEM and blaGES, while Pa strains blaIMP, blaVIM, blaNDM, blaVEB, blaGES and blaTEM, with high variations depending on the geographical zone and the sampling point. The WGS analysis revealed the presence of antibiotic resistance genes (ARGs) to other antibiotic classes, such as aminoglycosides, tetracyclines, sulphonamides, fosfomycin, phenicols, trimethoprim-sulfamethoxazole as well as class 1 integrons. The molecular analyses highlighted: (i) The presence of epidemic clones such as ST2 for Ab and ST233 and ST357 for Pa; (ii) The relatedness between clinical and hospital wastewater strains and (iii) The possible dissemination of clinical Ab belonging to ST2 (also proved in the conjugation assays for blaOXA-23 or blaOXA-72 genes), ST79 and ST492 and of Pa strains belonging to ST357, ST640 and ST621 in the wastewaters.ConclusionOur study reveals the presence of CP-producing Ab and Pa in all sampling points and the clonal dissemination of clinical Ab ST2 strains in the wastewaters. The prevalent clones were correlated with the presence of class 1 integrons, suggesting that these isolates could be a significant reservoir of ARGs, being able to persist in the environment.

Epidemiology of Bacterial Infections in the Maternal Intensive Care Unit of Ibn Tofail Hospital, Marrakech

Background: The purpose of this study is to evaluate the epidemiology and analyse the level of antibiotic resistance of Ab strains in the intensive care unit of the ibn Tofail Hospital of the Mohammed VI University Hospital of Marrakech. Results: Microbiologically, 200 samples were analyzed, of which urine was the most frequent sample with a rate of 36% of all samples, followed by blood cultures with a rate of 36%, catheters in 12%, vaginal samples in 7% and protected distal samples in 3%. The analysis of the resistance profile of germs to antibiotics showed that for Beta-lactams: 81% are extended-spectrum beta-lactamases (ESBL) 16% low level penicillinase (LLP) and high level penicillinase (HLP) at 3%.

Epidemiological Aspect and Antibiotic Resistance Profile of Acinetobacter baumannii in the Resuscitation Department of Ibn Tofail Hospital CHU Med V

Background: Multidrug resistant Acinetobacter baumannii, (MRAB) is an important cause of hospital acquired infection. The purpose of this study is to evaluate the epidemiology and analyze the level of antibiotic resistance of Ab strains in the intensive care unit of the ibn Tofail Hospital of the Mohammed VI University Hospital of Marrakech. Material and method: This study is a retrospective review of a city hospital epidemiology data base and includes 42 isolates of Acinetobacter baumannii (AB) from 120 patients. The antibiogram was performed according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations. Results: In our study, all bacteriological samples were taken from the intensive care unit. The mean age was 48.2 years with extremes ranging from 19 to 72 years.88 patients were male (73.4% of all cases) and 32 female (26.6%).The most frequent reason for hospitalization in the intensive care unit was severe head trauma in 35 cases (29%).During the study period, out of 120 samples received, 42 Ab strains were isolated (35% of samples). These strains were mainly isolated from blood cultures (40%). Conclusions: The diffusion of multi-resistant Ab strains in intensive care units seems to be alarming, hence the need to implement an effective strategy to fight nosocomial infections.

Age-dependent effects of embryonic ethanol exposure on anxiety-like behaviours in young zebrafish: A genotype comparison study

Fetal Alcohol Spectrum Disorder (FASD) is characterized by a variety of morphological, behavioural and cognitive deficits, ranging from mild to severe. Numerous animal models, including the zebrafish, have been employed to better understand the onset, expression and progression of this disorder. Embryonic ethanol-induced deficits in learning and memory, anxiety, social responses and elevated alcohol self-administration have been successfully demonstrated in zebrafish. Studies in zebrafish have also shown the expression of these behavioural deficits depends upon the developmental stage of ethanol exposure, the age of observation, as well as the genotype (strain or population origin) of the tested zebrafish. Here, we investigate how the genotype and age of observation may influence embryonic ethanol-induced alterations in anxiety-like responses in zebrafish. Zebrafish embryos exposed to either 0% or 1% (vol/vol) ethanol at 24hpf were tested in an open tank at one of three stages: larval (6–8 days post fertilization (dpf)), mid-larval (16-18dpf), or juvenile (26-28dpf). Two genotypes were tested in this manner, ABNS (a quasi-inbred strain) and ABSK (a mix of AB, TU and TL strains). We found embryonic ethanol induced behavioural changes to significantly differ depending on the genotype and age of observation. For example, significant differences between control and ethanol exposed zebrafish in both genotypes were observed in juvenile zebrafish, but few significant treatment effects were observed in larval zebrafish. Additionally, ethanol appeared to alter anxiety-like behaviours in the ABNS genotype but did not have as robust of an effect on the ABSK genotype. Lastly, there were significant behavioural differences between unexposed (control) zebrafish of the two genotypes, suggesting baseline behavioural differences despite a common AB genetic origin.

Different wild type strains of zebrafish show divergent susceptibility to TNBS-induced intestinal inflammation displaying distinct immune cell profiles

Little is known about the diversity in immune profile of the different wild type strains of zebrafish (Danio rerio), despite its growing popularity as an animal model to study human diseases and drug testing. In the case of data resulting from modeling human diseases, differences in the background Danio fishes have rarely been taken into consideration when interpreting results and this is potentially problematic, as many studies not even mention the source and strain of the animals. In this study, we hypothesized that different wild type zebrafish strains could present distinct immune traits. To address the differences in immune responses between two commonly used wild type strains of zebrafish, AB and Tübingen (TU), we used an intestinal inflammation model induced by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) and characterized the susceptibility and immune profile in these two strains. Our data demonstrates significant differences in survival between AB and TU strains when exposed to TNBS, suggesting important physiological differences in how these strains respond to inflammatory challenges. We observed that the AB strain presented increased mortality, higher neutrophilic intestinal infiltration, decreased goblet cell numbers and decreased IL-10 expression when exposed to TNBS, compared to the TU strain. In summary, our study demonstrates strain-specific immunological responses in AB and TU animals. Finally, the significant variations in strain-related susceptibility to inflammation and the differences in the immune profile shown here, highlight that the background of each strain need to be considered when utilizing zebrafish to model diseases and for drug screening purposes, thus better immune characterization of the diverse wild type strains of zebrafish is imperative.

Molecular Epidemiology of Carbapenem-Resistant Acinetobacter baumannii Isolates from Northern Africa and the Middle East.

At the Bundeswehr Hospitals of Hamburg and Westerstede, patients repatriated from subtropical war and crisis zones of Northern Africa and the Middle East were medically treated, including microbiological assessment. Within a six-year interval, 16 Acinetobacter spp. strains, including 14 Acinetobacter baumannii (Ab) isolates with resistance against carbapenems and origins in Afghanistan (n = 4), Iraq (n = 2), Libya (n = 2), and Syria (n = 8) were collected. While clonal relationships of Libyan and Syrian strains had been assessed by superficial next generation sequencing (NGS) and “DiversiLab” repetitive elements sequence-based (rep-)PCR so far, this study provides core genome-based sequence typing and thus more detailed epidemiological information. In detail, sequencing allowed a definitive species identification and comparison with international outbreak-associated Ab strains by core genome multi locus sequence typing (cgMLST) and the identification of MLST lineages, as well as the identification of known resistance genes. The sequence analysis allowed for the confirmation of outbreak-associated clonal clusters among the Syrian and Afghan Ab isolates, indicating likely transmission events. The identified acquired carbapenem resistance genes comprised blaOXA-23, blaOXA-58, blaNDM-1, and blaGES-11, next to other intrinsic and acquired, partly mobile resistance-associated genes. Eleven out of 14 Ab isolates clustered with the previously described international clonal lineages IC1 (4 Afghan strains), IC2 (6 Syrian strains), and IC7 (1 Syrian strain). Identified Pasteur sequence types of the 14 Ab strains comprised ST2 (Syrian), ST25 (Libyan), ST32 (Iraqi), ST81 (Afghan), ST85 (Libyan), and ST1112 (Syrian), respectively. In conclusion, the study revealed a broad spectrum of resistance genes in Ab isolated from war-injured patients from Northern Africa and the Middle East, thereby broadening the scarcely available data on locally abundant clonal lineages and resistance mechanisms.

Field application of allelopathic bacteria to control invasion of little seed canary grass in wheat.

Development of successful biological weed control can help to resolve various environmental challenges created by the chemical and mechanical weed control. The current study is aimed at investigating the potential of allelopathic bacteria (hereinafter as AB) for biological weed control in wheat rather than the traditional areas of plant allelopathy, phyto-pathology, and insect biocontrol agents. Eleven strains of AB were obtained that were inhibitory to little seed canary grass of which 5 also inhibited wheat in our previous studies. The remaining strains indicated the potential for biological control of this weed in wheat. Five efficient strains were selected for this purpose to conduct pot and field trials. Seeds of little seed canary grass were sown together in potted soils with wheat seeds inoculated with AB strains. A subsequent field trial was conducted at a site selected based on chronic infestations of canary grass. Seeds of the weed and inoculated wheat were co-seeded directly in field soil. For inoculation, these strains were formulated in sterilized peat and applied to seeds. In pot trials, the invasion of little seed canary grass in wheat reduced wheat grain yield up to 59.9%. Four strains suppressed the weed which resulted in recovery wheat grain yield losses from 20.1 to 66.9%. The field trial showed that the invasion of little seed canary grass reduced wheat grain yields up to 53.9%. Four strains suppressed the weed which resulted into recovery of grain wheat grain yield losses 34.3 to 64.3%. These findings were consistent with improvement of other agronomic, physiological, and chemical parameters of the crop where the four strains of AB (L9, T42, 7O0, and O010) were applied.

Molecular Epidemiology of Carbapenem-Resistant Acinetobacter baumannii Isolated from War-Injured Patients from the Eastern Ukraine.

Recently, a total of 32 carbapenem- and fluoroquinolone-resistant Acinetobacter baumannii (Ab) isolates was isolated from war-injured patients who were treated at German Bundeswehr Hospitals, and preliminarily typed by “DiversiLab” repetitive elements sequence-based (rep-) PCR. Core genome-based sequence typing was also used to provide more detailed epidemiological information. From the clusters observed by rep-PCR, selected Ab strains were subjected to Next Generation Sequencing (NGS) in order to compare them with international outbreak-associated Ab strains and to identify MLST (multi-locus sequence type) lineages, as well as to identify known resistance genes. Accordingly, NGS indicated higher diversity than rep-PCR, but also confirmed likely transmission events. The identified acquired carbapenem-resistant genes comprised blaOXA-23, blaOXA-72 and blaGES-12, as well as various other intrinsic and acquired resistance-associated genetic elements. All isolates clustered with the previously identified international clonal lineages IC1, IC2, IC6 and IC7, with corresponding Pasteur sequence types ST1, ST2, ST78 and ST25, respectively. In conclusion, the assessment confirmed a broad spectrum of resistance-associated genes in Ab isolated from war-injured patients from the Eastern Ukraine, and provided the first insights into locally abundant clonal lineages.

Detection of 5 Kinds of Genes Related to Plasmid-Mediated Quinolone Resistance in Four Species of Nonfermenting Bacteria with 2 Drug Resistant Phenotypes.

Objective This study aimed to detect 5 kinds of genes related to plasmid-mediated quinolone resistance in four species of nonfermenting bacteria with 2 drug resistance phenotypes (multidrug resistance and pandrug resistance), which were Acinetobacter baumannii (Ab), Pseudomonas aeruginosa (Pa), Stenotrophomonas maltophilia (Sm), and Elizabethkingia meningoseptica (Em). Methods The Phoenix NMIC/ID-109 panel and API 20NE panel were applied to 19 isolated strains, including 6 Ab strains (2 strains with multidrug resistance and 4 strains with pandrug resistance), 6 Pa strains (3 strains with multidrug resistance and 3 strains with pandrug resistance), 4 Sm strains (2 strains with multidrug resistance and 2 strains with pandrug resistance), and 3 Cm strains (2 strains with multidrug resistance and 1 strain with pandrug resistance). After strain identification and drug susceptibility test, PCR was applied to detect 5 genes related to plasmid-mediated quinolone resistance. The genes detected were quinolone resistance A (qnrA), aminoglycoside acetyltransferase ciprofloxacin resistance variant, acc(6′)-Ib-cr, and 3 integrons (intI1, intI2, and intI3). The amplified products were analyzed by 1% agarose gel electrophoresis and sequenced. Sequence alignment was carried out using the bioinformatics technique. Results Of 19 strains tested, 8 strains carried acc(6′)-Ib-cr and 6 of them were of pandrug resistance phenotype (3 Ab strains, 2 Pa strains, and 1 Sm strain). The carrying rate of acc(6′)-Ib-cr was 60.0% for strains of pandrug resistance (6/10). Two strains were of multidrug resistance (1 Ab strain and 1 Pa strain), and the carrying rate of acc(6′)-Ib-cr was 22.0% (2/9). The carrying rate was significantly different between strains of multidrug resistance and pandrug resistance (P < 0.05). The class 1 integron was detected in 11 strains, among which 6 strains were of pandrug resistance (3 Ab strains, 2 Pa strains, and 1 Sm strain). The carrying rate of the class 1 integron was 60.0% (6/10). Five strains were of multidrug resistance (3 Pa strains, 1 Ab strain, and 1 Em strain), and the carrying rate was 55.6% (5/9). The carrying rate of the class 1 integron was not significantly different between strains of multidrug resistance and pandrug resistance (P > 0.05). Both acc(6′)-Ib-cr and intI1 were detected in 6 strains, which were negative for qnrA, intI2, and intI3. Conclusion Quinolone resistance of isolated strains was related to acc(6′)-Ib-cr and intI1 but not to qnrA, intI2, or intI3. The carrying rate of acc(6′)-Ib-cr among the strains of pandrug resistance was much higher than that among the strains of multidrug resistance. But, the strains of two drug resistant phenotypes were not significantly different in the carrying rate of intI1. The detection rates of the two genes were high and similar in Ab and Pa strains. 1 Em strain carried the class 1 integron.