Genera Citrobacter Research Articles

Poultry slaughterhouse wastewater as a source of bacterial antimicrobial resistance.

Slaughterhouses produce huge volumes of effluents throughout the production chain that, when discharged untreated into bodies of water, can become a source of environmental contamination. This is particularly worrisome if these effluents are used for irrigation since they increase contamination levels and spread pathogens and resistance determinants to humans and animals. Therefore, in this study, we assessed antimicrobial resistance in bacteria isolated from inlet water, equalization wastewater tanks, treatment plant wastewater, and treated wastewater in slaughterhouse facilities in Rio de Janeiro, Brazil. Four samples were collected at each of the collection points, between June 2021 and July 2022. Following bacterial isolation and identification, the samples were analyzed for antimicrobial resistance using the disk diffusion method to test aminoglycoside, beta-lactam, and fluoroquinolone antimicrobials. A total of 229 bacteria were isolated, with 74 isolates selected from the genera Citrobacter (12), Enterobacter (14), Klebsiella (35), Serratia (5), and Pseudomonas (8). Inlet water had the lowest number of isolates and was the only point with gentamicin-resistant isolates. Raw effluent from the equalization tank showed the highest number of isolated bacteria and resistance levels, followed by treated wastewater and the treatment plant. Across all samples, a high rate of cefoxitin-resistance was observed among the isolated bacteria. Klebsiella pneumoniae stood out as the species that demonstrated the greatest resistance to a variety of antimicrobials. These results highlight the importance of water quality monitoring in mitigating public health and environmental risks and high antimicrobial resistance levels.

Citrobacter Causing Septic Arthritis: A Case Report

Abstract The genus Citrobacter commonly found in water and soil as well as the intestinal and urinary tracts of animals and humans. Although Citrobacter infections are infrequently diagnosed in environmental contexts, the rising incidence of nosocomial manifestations underscores the importance of considering this organism in the differential diagnosis of hospital-acquired infections. We present a case of patient with septic arthritis of the shoulder who had been originally admitted for the management of acute-on-chronic congestive heart failure exacerbation and severe sepsis. On hospital day 1, joint aspiration cultures and Gram stain confirmed the presence of Citrobacter koseri, a pathogen not commonly associated with septic arthritis, and ceftriaxone was administered to target it. On hospital day 7, antibiotic was transitioned to levofloxacin, every other day for 4 weeks. The patient was discharged to an acute rehabilitation facility after a 14-day hospital stay. This case stresses the importance of maintaining a broad differential diagnosis for any patients who present with fever and joint inflammation or swelling, especially in a postoperative setting.

Fine-scale geographic difference of the endangered Big-headed Turtle (Platysternon megacephalum) fecal microbiota, and comparison with the syntopic Beale’s Eyed Turtle (Sacalia bealei)

BackgroundStudies have elucidated the importance of gut microbiota for an organism, but we are still learning about the important influencing factors. Several factors have been identified in helping shape the microbiome of a host, and in this study we focus on two factors—geography and host. We characterize the fecal microbiota of the Big-headed Turtle (Platysternon megacephalum) and compare across a relatively fine geographic scale (three populations within an 8-km radius) and between two syntopic hosts (P. megacephalum and Sacalia bealei). Both species are endangered, which limits the number of samples we include in the study. Despite this limitation, these data serve as baseline data for healthy, wild fecal microbiotas of two endangered turtle species to aid in conservation management.ResultsFor geography, the beta diversity of fecal microbiota differed between the most distant sites. The genus Citrobacter significantly differs between sites, which may indicate a difference in food availability, environmental microbiota, or both. Also, we identify the common core microbiome for Platysternon across Hong Kong as the shared taxa across the three sites. Additionally, beta diversity differs between host species. Since the two species are from the same site and encounter the same environmental microbiota, we infer that there is a host effect on the fecal microbiota, such as diet or the recruitment of host-adapted bacteria. Lastly, functional analyses found metabolism pathways (KEGG level 1) to be the most common, and pathways (KEGG level 3) to be statistically significant between sites, but statistically indistinguishable between species at the same site.ConclusionsWe find that fecal microbiota can significantly differ at a fine geographic scale and between syntopic hosts. Also, the function of fecal microbiota seems to be strongly affected by geographic site, rather than species. This study characterizes the identity and function of the fecal microbiota of two endangered turtle species, from what is likely their last remaining wild populations. These data of healthy, wild fecal microbiota will serve as a baseline for comparison and contribute to the conservation of these two endangered species.

Comparing the Bacterial Flora of Insectary and Filed Strains of Supella longipalpa (Blattaria: Ectobiidae) and Their Antibiotic Resistant Pattern in Qom Province, Central Iran.

Cockroaches play a role in the mechanical transmission of microbial pathogens. This study was designed to determine the isolated bacteria and their susceptibility to conventional antibiotics from brown-banded cockroach, Supella longipalpa, in Qom province, central Iran. In this cross-sectional study, brown-banded cockroaches were bred in an insectary and caught from hospitals of Qom. The samples were taken from the surface and alimentary canal and then cultured on microbial culture media; next, grown specimens were identified using differential culture media. Finally, after performing diagnostic tests and identifying the bacteria species, their susceptibility to various antibiotics was evaluated. A total of 120 adult cockroaches from the insectary and hospitals were included in the study. Ten bacterial genera were found; nine were Gram-negative and one was Gram-positive. The genus Klebsiella, Enterobacter, Staphylococcus, Citrobacter and Hafnia were isolated only from the hospital strain. On the other hand, Pseudomonas and Escherichia from both groups and other species such as Salmonella, Proteus and Shigella were isolated only from laboratory strains. The highest antibiotic resistance among Gram-positive cocci and Gram-negative bacilli were 100.0% and 98.1% for ampicillin and Ceftazidime, respectively. The results of this study showed that various pathogenic bacteria harbored by brown-banded cockroaches. Moreover, it was found that most of these bacteria belong to the Enterobacteriaceae family, which can be pathogenic and thus threaten human health.

Antibiotic-Resistant Bacteria across a Wastewater Treatment Plant

Antimicrobial resistance is presently one of the leading causes of death worldwide. The surveillance of different environments, namely, wastewater treatment plants (WWTPs), as hotspots of antibiotic-resistant bacteria, has become crucial under the One Health approach. This study aimed to characterize, phenotypically and genotypically, antibiotic-resistant bacteria along a WWTP receiving domestic and industrial sewage. Four sampling sites, representing distinct treatment points of the WWTP, were selected for sampling bacterial isolation in selective media supplemented, or not, with antibiotics, and subsequent antimicrobial susceptibility testing. Antibiotic resistance encoding genes were screened by molecular methods. A total of 50 bacterial isolates were obtained, 50% of which were affiliated with the genus Enterococcus. The antimicrobial susceptibility testing revealed antibiotic phenotypic resistance in isolates obtained from all the four treatment points of the wastewater samples, with resistance to tetracycline (32.5%) and ampicillin (25%) being the most common. Three isolates were found to be multidrug resistant and were affiliated with the genera Citrobacter, Shigella and Klebsiella. Molecular screening revealed the presence of tet(M), blaTEM, blaSHV and blaCTX-M, as well as class 1 integrons carrying dfrA25, ANT(3″)-IIa and aadA6 genes. This study highlights the relevance of bacterial isolation and their antimicrobial susceptibility evaluation in WWTP systems since antibiotic-resistant strains were found from the raw influent to the final effluent discharged into the environment, denoting the need for surveillance and containment measures.

Citrobacter enshiensis sp. nov., isolated from seleniferous soil.

Two Gram-stain-negative, facultative anaerobic, rod-shaped bacterial strains, S171T and S2-9, were isolated from seleniferous soil in China. Comprehensive phylogenetic analyses based on 16S rRNA genes, multilocus sequences and whole genome sequences indicated that the two strains belonged to the genus Citrobacter. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values of strains S171T and S2-9 with the closest relative Citrobacter koseri NCTC 10786T were 83.6-83.7% and 27.7-27.8 %, respectively, which were below the species cutoff values. The ANI and dDDH values between the two strains were 97.9% and 84.8 %, respectively. The biochemical characteristics revealed that selenite tolerance, H2S and indole production, arginine dihydrolase, ornithine decarboxylase, as well as acid production from carbon sources such as d-sorbitol and arbutin are distinctive features of the two strains. Based on these results, strain S171T and strain S2-9 represent a novel species of the genus Citrobacter, for which the name Citrobacter enshiensis sp. nov. is proposed, with strain S171T (=GDMCC 1.3637T=JCM 35851T) as the type strain. The genome size of strain S171T was 4.92 Mb with a G+C content of 52.6 mol%. The genome size of strain S2-9 was 4.89 Mb with a G+C content of 52.6 mol%.

Associations Between Gut Microbial Features and Sickness Symptoms in Kidney Transplant Recipients.

The study investigated the relationship of gut microbiome features and sickness symptoms in kidney transplant recipients. Employing a prospective, longitudinal design, we collected data from 19 participants who had undergone living-donor kidney transplant at three timepoints (pre-transplant and 1week and 3months post-transplant). Sickness symptom data and fecal specimens were collected at each timepoint. Participants were grouped either as high or low sickness symptom severity at baseline. Shotgun metagenomics sequencing characterized gut microbial structure and functional gene content. Fecal microbial features, including alpha (evenness and richness within samples) and beta (dissimilarities between samples) diversity and relative abundances, were analyzed using R statistical packages. Cross-sectional and longitudinal analyses examined relationships between gut microbial features and sickness symptoms. Although our exploratory findings revealed no significant differences in alpha and beta diversity between groups, the high-severity group showed lower microbial richness and evenness than the low-severity group. The high-severity group had enriched relative abundance of bacteria from the genera Citrobacter and Enterobacter and reduced relative abundance of bacteria from the genus Akkermansia across timepoints. No functional genes differed significantly between groups or timepoints. Kidney transplant recipients with high symptom burden displayed increased putative proinflammatory bacteria and decreased beneficial bacteria. This study provides an effect size that future large cohort studies can employ to confirm associations between gut microbial features and sickness symptom experiences in the kidney transplant population. The study findings also have implications for future interventional studies aiming to alleviate the sickness symptom burden in this population.

Interactions between Balantidium ctenopharyngodoni and microbiota reveal its low pathogenicity in the hindgut of grass carp

BackgroundHosts, parasites, and microbiota interact with each other, forming a complex ecosystem. Alterations to the microbial structure have been observed in various enteric parasitic infections (e.g. parasitic protists and helminths). Interestingly, some parasites are associated with healthy gut microbiota linked to the intestinal eubiosis state. So the changes in bacteria and metabolites induced by parasite infection may offer benefits to the host, including protection from other parasitesand promotion of intestinal health. The only ciliate known to inhabit the hindgut of grass carp, Balantidium ctenopharyngodoni, does not cause obvious damage to the intestinal mucosa. To date, its impact on intestinal microbiota composition remains unknown. In this study, we investigated the microbial composition in the hindgut of grass carp infected with B. ctenopharyngodoni, as well as the changes of metabolites in intestinal contents resulting from infection.ResultsColonization by B. ctenopharyngodoni was associated with an increase in bacterial diversity, a higher relative abundance of Clostridium, and a lower abundance of Enterobacteriaceae. The family Aeromonadaceae and the genus Citrobacter had significantly lower relative abundance in infected fish. Additionally, grass carp infected with B. ctenopharyngodoni exhibited a significant increase in creatine content in the hindgut. This suggested that the presence of B. ctenopharyngodoni may improve intestinal health through changes in microbiota and metabolites.ConclusionsWe found that grass carp infected with B. ctenopharyngodoni exhibit a healthy microbiota with an increased bacterial diversity. The results suggested that B. ctenopharyngodoni reshaped the composition of hindgut microbiota similarly to other protists with low pathogenicity. The shifts in the microbiota and metabolites during the colonization and proliferation of B. ctenopharyngodoni indicated that it may provide positive effects in the hindgut of grass carp.

A brief insight into Citrobacter species - a growing threat to public health

Citrobacter spp. are Gram-negative, non-spore forming, rod-shaped, facultative anaerobic bacteria from the Enterobacteriaceae family often found in soil, sewage, sludge, water, food, and the intestinal tracts of animals and humans. Several members of Citrobacter spp. especially C. freundii, C. koseri, C. braakii are frequently detected in newborn illnesses, urinary tract infections, and patients with severe underlying conditions, including hypertension, diabetes, cancer, and respiratory infections, or those who are immunocompromised. Strains of Citrobacter spp. can spread vertically or horizontally from carriers or other hospital sources and thus cause nosocomial infections in hospital settings. A total of 19 Citrobacter genomospecies have been recognized based on genomics. It has been noted that the Citrobacter genus acquired antimicrobial resistance and virulence, including invasion, colonization, biofilm formation, and toxin production. The recent emergence and spread of antimicrobial resistance to β-lactams, carbapenems, fluoroquinolones, aminoglycosides, and colistin in Citrobacter spp. through chromosomal and plasmid-mediated resistance limits the empiric treatment options. Therefore, combination therapy involving costly and potentially hazardous antibiotics poses significant challenges in treating Citrobacter infections. Here we summarized the nomenclature of Citrobacter spp., clinical manifestations, epidemiology, pathogenesis, antibiotic resistance mechanisms, and treatments from various clinical samples. This review will expand our knowledge of the genomics and epidemiology of Citrobacter spp., enabling improved control of infections and the spread of these organisms.

A multiscale study of the effects of a diet containing CdSe/ZnS-COOH quantum dots on Salmo trutta fario L.: Potential feed-related nanotoxicity

Quantum dots (QDs) receive widespread attention in industrial and biomedical fields, but the risks posed by the use of nanoparticles to aquatic organisms and the associated toxicological effects are still not well understood. In this study, effects of the 7-day dietary exposure of Salmo trutta fario L. juveniles to CdSe/ZnS-COOH QDs were evaluated at molecular, cellular, physiological and whole-organism levels. Fish feeding with QDs-contaminated feed resulted in an increased somatic index of the liver, a genotoxic effect on peripheral blood erythrocytes, altered enzyme activity and decreased MDA level. Furthermore, Cd levels in the gills and liver tissues of the exposed fish were found to be significantly higher than in those of the control fish. Alpha diversity indexes of the gut microbiota of the QDs-exposed S. trutta fario L. individuals exhibited a decreasing trend. The principal coordinate analysis (PCoA) showed that the gut microbiota of the control fish was significantly different from that of the fish exposed to QDs (p < 0.05). Additionally, the linear discriminant analysis (LDA) performed using an effect size (LEfSe) algorithm unveiled 19 significant taxonomic differences at different taxonomic levels between the control group and the QDs-exposed group. In the QDs-exposed group, the relative abundance of the genus Citrobacter (Proteobacteria phylum) in the gut microbiota was found to be significantly increased whereas that of the genus Mycoplasma (Tenericutes phylum) significantly decreased compared to the control group. In summary, QDs-contaminated diet affects the gut microbiota of fish by significantly changing the relative abundance of some taxa, potentially leading to dysbiosis. This, together with morphophysiological, cytogenetic and biochemical changes, poses a risk to fish health.

Human Breast Tissue Microbiota Reveals Unique Microbial Signatures that Correlate with Prognostic Features in Adult Ethiopian Women with Breast Cancer.

Breast cancer (BC) is the leading cause of cancer mortality among women in Ethiopia. Overall, women of African ancestry have the highest death toll due to BC compared to other racial/ethnic groups. The cause of the disparity in mortality is unclear. Recently, studies conducted in the United States and other high-income countries highlighted the role of microbial dysbiosis in BC initiation, tumor growth, and treatment outcome. However, the extent to which inter-individual differences in the makeup of microbiota are associated with clinical and histopathological outcomes in Ethiopian women has not been studied. The goal of our study was to profile the microbiome in breast tumor and normal adjacent to tumor (NAT) tissues of the same donor and to identify associations between microbial composition and abundance and clinicopathological factors in Ethiopian women with BC. We identified 14 microbiota genera in breast tumor tissues that were distinct from NAT tissues, of which Sphingobium, Anaerococcus, Corynebacterium, Delftia, and Enhydrobacter were most significantly decreased in breast tumors compared to NAT tissues. Several microbial genera significantly differed by clinicopathological factors in Ethiopian women with BC. Specifically, the genus Burkholderia more strongly correlated with aggressive triple negative (TNBC) and basal-like breast tumors. The genera Alkanindiges, Anoxybacillus, Leifsonia, and Exiguobacterium most strongly correlated with HER2-E tumors. Luminal A and luminal B tumors also correlated with Anoxybacillus but not as strongly as HER2-E tumors. A relatively higher abundance of the genus Citrobacter most significantly correlated with advanced-stage breast tumors compared to early-stage tumors. This is the first study to report an association between breast microbial dysbiosis and clinicopathological factors in Ethiopian women.

Bioremediation by bacteria isolated from water contaminated with hydrocarbons

Oil pollution is currently a global problem. However, an oil-contaminated ecology is rich in microorganisms that may utilize petroleum oil and hydrocarbons for growth, feeding, and metabolic processes. In the present study, fifty polluted water samples were collected from five stations (ten samples each) in the Al-Fahama oil refinery in eastern Baghdad. The water contamination parameters of these collected water samples were detected. Then, the percentage of water contamination with some heavy metals (zinc, lead, and cadmium) and radioactive elements (uranium, cesium and actinium) was measured. The proportions of these elements were compared within their limits permitted by the World Health Organization (WHO). Fifty-nine bacterial isolates were isolated from polluted water, and 24 isolates of them succeeded in analyzing crude oil. The results of the current study showed that seven isolates belong to the genus Citrobacter amalonaticus (29.16%), six isolates belong to Enterobacter cloacae (25%), three isolates belonged to both Pseudomonas aeruginosa (12.5%) and Ochrobacterum anthropi (12.5%), and human Ochrobacterum. With a percentage of 12.5%, two isolates of Serratia marcescens (8.3%) and one isolate of each Pseudomonas fluorescens, Serratia fonticola, and Burkholderia pseudomallei (4.16%) of each. The optimum of some conditions for the decomposition process was determined in terms of (pH, temperature and crude oil concentration) and the results showed that the optimum degradation conditions were 35°C at pH equal to 7.5 in the presence of 2% of crude oil. Several experiments were conducted to determine the most efficient isolates for oil analysis. Burkholderia pseudomallei and Pseudomonas fluorescens are the most active bacterial species in their oil degradation. Genes responsible for hydrocarbon analysis were revealed in twenty-four bacterial isolates using a polymerase chain reaction (PCR) assay. The results showed that the ALKB gene (alkane hydroxylase) was observed in all bacterial isolates that succeeded in analyzing crude oil with a percentage equal to 100%, NahAc gene (naphthalene dioxygenase) has been recorded in four isolates (16.7%), these four bacterial isolates were Burkholderia pseudomallei, Pseudomonas aeruginosa, Ochrobacterum anthropic, and Pseudomonas fluorescens. Generally, the isolation rate of both C. amalonaticus and E. cloacae isolates was higher than in other studies, which may be due to the hydrocarbon pollution in isolation; both B. pseudomallei and P. fluorescens isolates were the highest active bacterial species in their oil degradation. Genetic results showed that the AlkB gene was the domain compared with other degradation genes used in the current study, followed by NahAc gene. Keywords: Bioremediation, heavy metal, B. pseudomallei, hydrocarbons, crude oil

Dominant sanitary significant microflora of meat

We conducted bacteriological study of samples of small-sized beef, as well as minced pork, beef, homemade, purchased in retail chains. Bacteriological, bacterioscopic and proteomic research methods were used. The total bacterial contamination, freshness indicators, the presence of pathogens of bacterial diseases, opportunistic microorganisms and representatives of the dominant saprophytic microflora were determined. The absence of Salmonella, listeria, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus, yeast and molds was established. The dominant microflora of meat are Enterobacteria of the genus Citrobacter, Entrrococcus faecium.

Pangenome-driven insights into nitrogen metabolic characteristics of Citrobacter portucalensis strain AAK_AS5 associated with wastewater nitrogen removal.

Nitrogen metabolism in the genus Citrobacter is very poorly studied despite its several implications in wastewater treatment. In the current study, Citrobacter portucalensis strain AAK_AS5 was assessed for remediation of simulated wastewater supplemented with different inorganic nitrogen sources. Combination of (NH4)2SO4 with KNO3 was the most preferred for achieving high growth density followed by (NH4)2SO4 and KNO3 alone. This was in agreement with highest ammonical nitrogen removal of 92.9% in the presence of combined nitrogen sources and the corresponding nitrate nitrogen removal of 93% in the presence of KNO3. Furthermore, these removal capacities were validated by investigating the uniqueness and the spread of metabolic features through pan-genomic approach that revealed the largest number of unique genes (2097) and accessory genes (705) in strain AAK_AS5. Of the total 44 different types of nitrogen metabolism-related genes, 39 genes were associated with the core genome, while 5 genes such asgltI,nasA,nasR,nrtA,and ntrCuniquely belonged to the accessory genome. Strain AAK_AS5 possessed three major nitrate removal pathwaysviz., assimilatory and dissimilatory nitrate reduction to ammonia (ANRA & DNRA), and denitrification; however, the absence of nitrification was compensated by ammonia assimilation catalyzed by gene products of the GDH and GS-GOGAT pathways. narGHIJ encoding the respiratory nitrate reductase was commonly identified in all the studied genomes, while genes such as nirK, norB, and nosZ were uniquely present in the strain AAK_AS5 only. A markedly different genetic content and metabolic diversity between the strains reflected their adaptive evolution in the environment thus highlighting the significance of C. portucalensis AAK_AS5 for potential application in nitrogen removal from wastewater.

Gut Bacteria of Snakeheads of Chinadi Beel, Narsingdi and Their Antibiogram Profile

The gut bacteria of snakehead fish (Channa punctata, C. marulius and C. striata) collected from Chinadi beel, Narsingdi, Bangladesh was characterized and formulated their antibiogram profile. The mean richness of intestinal bacteria in C. punctata was significantly higher in comparison to C. marulius and C. striata. A total of 24 isolates under the genus Bacillus, Enterobacter, Citrobacter, Kluyvera, Vibrio, Pseudomonas and Acinetobacter were identified. The strains of Enterobacter and Pseudomonas showed 100% resistance to eight antibiotics. The isolates of C. punctata were found to be resistant to nine antibiotics followed by C. marulius (8) and C. striata (7) indicating a critical condition of Chinadi beel of being polluted by anthropogenic activities. Bangladesh J. Bot. 52(2): 297-306, 2023 (June)

Impacts on gut microbiota of rats with high-fat diet supplemented by herbs of Melissa officinalis, Lavandula angustifolia and Salvia officinalis

Medicinal plants are used in traditional, folk medicine and veterinary practice to treat and prevent exacerbations of chronic diseases, diseases of the cardiovascular and nervous systems, respiratory and digestive organs, liver, bile ducts, kidneys, urinary tract, to regulate metabolism and to boost immunity, etc. The therapeutic effect on the body is exerted by biologically active substances (alkaloids, glycosides, tannins, essential oils, and others) that are present in various parts of plants. Understanding the issue of interaction between the intestinal microbiota and drugs based on medicinal plants will contribute to the development of treatment protocols for various diseases, including chronic ones, by the normalization of impaired functions due to plant origin substances. In this study, we determined the effect of Melissa officinalis, Lavandula angustifolia, Salvia officinalis on the intestinal microbiota of white rats fed a high-fat diet. The addition of 5% crushed young dry shoots of S. officinalis, L. angustifolia, M. officinalis to the high-fat diet of laboratory rats significantly changed the quantitative ratio of Escherichia coli with normal and altered enzymatic properties in the intestinal content. The number of typical E. coli in rats fed with S. officinalis and L. angustifolia decreased by 1.7 and 1.6 times; non-lactose fermenting form of E. coli, on the contrary, increased by 1.8–2.1 times in rats fed with any of the medicinal plants compared to the control. Amid the addition of medicinal plants to the diet, it was not possible to isolate opportunistic enterobacteria of the genus Citrobacter, however, an increase in the number of the genus Candida fungi was observed.

Phenotypic and genotypic discrepancies for carbapenemase-producing Citrobacter freundii in multiple isolates from a single patient

BackgroundCarbapenemase-producing gram-negative organisms continue to be a significant healthcare concern and a therapeutic challenge. Members of the genus Citrobacter have emerged as increasingly multidrug resistant and versatile healthcare-associated pathogens. In this study we investigated five KPC-producing Citrobacter freundii isolates, from the same patient, that presented unusual phenotypic characteristics including false susceptibility to carbapenems detection by culture-based methods.MethodsThe isolates were tested for antimicrobial susceptibility using broth microdilution and disk diffusion. Production of serine carbapenemase was confirmed with the mCIM (modified carbapenem inactivation method) test. Genotypes were determined by PCR and whole genome sequencing analysis.ResultsThe five isolates were susceptible to meropenem by broth microdilution and presented varying colonial morphologies and levels of susceptibility to carbapenems by multiple phenotypic methods, despite being positive for carbapenemase production by mCIM and positive for blaKPC by PCR. Whole genome sequence analysis showed that three of the five highly related isolates harbor an additional gene cassette, including blaCARB-2, ant(2''), aadA2, dfrA19, catB3, cmlA1, mph(E), msr(E), and qnrA1. The presence of these genes explains the difference in phenotypes observed.ConclusionFailure to detect and completely eradicate the carbapenemase-producing C. freundii in the urine with ertapenem therapy, likely due to the presence of a heterogeneous population, resulted in the phenotypic and genotypic adaptations of the organism as it disseminated to the bloodstream and kidneys. The fact that carbapenemase-producing C. freundii can elude detection by phenotypic methods and can so easily acquire and transfer resistance gene cassettes is of concern.

Isolation, Identification, and Antibacterial Assay of Indigenous Bacterial Isolates from Apis cerana Honeycomb

Apis cerana is a honey bee species with a cavity hive known as the eastern honey bee. Honey bee hives have Indigenous bacteria that have antimicrobial potential. Indigenous bacteria are free bacteria that can synthesize nitrogen compounds, sugars, and other bioactive substances. This study aims to isolate, identify and test the antibacterial of Indigenous bacteria isolate Apis cerana against gram-positive Staphylococus aureus and gram-negative bacteria Escherichia coli. This study used a descriptive research method to obtain the data from laboratory experiments. The study consisted of isolating Indigenous bacteria, identifying and testing the antibacterial agar diffusion method. The study results obtained seven isolates of AC 1, AC 2, AC 3, AC 4, AC 5, AC 6, AC 7 Indigenous bacteria from Apis cerana nests. AC 1 isolate has similarities with the genus Streptococcus, AC 2 isolates have similarities with the Klebsiella genus, while AC 3 isolates have similarities with the Bacillus genus, and AC 4, AC 5, AC 6 and AC 7 isolates have similarities with the Citrobacter genus. Indigenous bacterial isolates with potential antibacterial potential where the most significant inhibition against Staphylococus aureus bacteria was shown by isolate AC 1 (10.79 mm). At the same time, the smallest was found in isolate AC 7 (8.52 mm). The most significant inhibition against Escherichia coli bacteria was shown by isolate AC 1 (9.0 mm) while the smallest was found in isolate AC 3 (7.4 mm). Apis cerana nests have indigenous bacteria that have the potential to produce antibacterial substances

Intestinal response of Rana chensinensis larvae exposed to Cr and Pb, alone and in combination

Although numerous investigations on the adverse impact of Cr and Pb have been performed, studies on intestinal homeostasis in amphibians are limited. Here, single and combined effects of Cr (104 μg/L) and Pb (50 μg/L) on morphological and histological features, bacterial community, digestive enzymes activities, as well as transcriptomic profile of intestines in Rana chensinensis tadpoles were assessed. Significant decrease in the relative intestine length (intestine length/snout-to-vent length, IL/SVL) was observed after exposure to Pb and Cr/Pb mixture. Intestinal histology and digestive enzymes activities were altered in metal treatment groups. In addition, treatment groups showed significantly increased bacterial richness and diversity. Tadpoles in treatment groups were observed to have differential gut bacterial composition from controls, especially for the abundance of phylum Proteobacteria, Firmicutes, Verrucomicrobia, Actinobacteria, and Fusobacteria as well as genus Citrobacter, Anaerotruncus, Akkermansia, and Alpinimonas. Moreover, transcriptomic analysis showed that the transcript expression profiles of GPx and SOD isoforms responded differently to Cr and/or Pb exposure. Besides, transcriptional activation of pro-apoptotic and glycolysis-related genes, such as Bax, Apaf 1, Caspase 3, PK, PGK, TPI, and GPI were detected in all treatment groups but downregulation of Bcl2 in Pb and Cr/Pb mixture groups. Collectively, these results suggested that Cr and Pb exposure at environmental relevant concentration, alone and in combination, could disrupt intestinal homeostasis of R. chensinensis tadpoles.

The gut microbiota diversity of five Orthoptera (Insecta, Polyneoptera) insects determined by DNA metabarcoding.

Most orthopteran insects are phytophagous and some are important pests in agriculture and forests. Many intestinal microflora of Orthoptera insects have been reported, primarily from Acridoidea and there have been few reports of other taxa. In this study, we collected 15 individuals representing five species (Ruspolialineosa, Tetrixjaponica, Erianthusversicolor, Gryllotalpaorientalis and Teleogryllusemma) belonging to five orthopteran superfamilies (Tettigonioidea, Tetrigoidea, Eumastacoidea, Gryllotalpoidea and Grylloidea) to characterise and compare the gut microbiota with greater taxonomic width by performing sequencing analysis of the 16S rRNA V4 region in gut material. A total of 606,053 high-quality sequences and 3,105 OTUs were acquired from 15 gut samples representing 24 phyla, 48 classes, 69 orders, 133 families and 219 genera. Firmicutes and bacteria were the most abundant phyla, followed by Bacteroidetes, Cyanobacteria, Actinobacteria and Acidobacteria. At the genus level, Serratia, Citrobacter, Wolbachia, Lactobacillus and Parabacteroides were the most predominant genera in R.lineosa, T.japonica, E.versicolor, G.orientalis and T.emma, respectively. Both Principal Coordinates Analysis (PCoA) and heatmap results revealed significant differences in bacterial community composition across species. Additionally, alpha diversity analysis indicated the bacterial richness was significantly different amongst the five species.