International Journal of Microbiology最新文献

Bluetongue (BT) is an arthropod-borne viral disease that primarily affects ruminants in tropical and temperate regions. In the present study, a cross-sectional survey was conducted to define the seroprevalence of Bluetongue virus and to identify the possible risk factors correlated with BTV seropositivity among cattle, sheep, and goats during the period 2015-2016 in Gadarif State. A total of 420 cattle, 877 sheep, and 641 goat serum samples were collected randomly from 12 localities. Information about age, sex, breed, area ecology, and location was obtained for each sample. Bluetongue seroprevalence was estimated using competitive enzyme-linked immunosorbent assay (cELISA). The overall seroprevalence of BTV was 92.9% (390/420), 76.4% (670/877), and 85.3% (547/641) among cattle, sheep, and goats, respectively. Multivariate analysis followed univariate analysis showed that there was a significant difference (p < 0.05) between location, area ecology and age groups of cattle, sheep, and goats, and seropositivity to BTV. In addition, a significant association (p < 0.05) was observed between sex and seropositivity to BTV in sheep. In conclusion, BTV antibodies are highly prevalent in Gadarif State and susceptible livestock are at risk of exposition with BTV. Consequently, these animals have protection against specific BTV serotypes.

Background: Streptococcus pyogenes is the most frequent cause of pharyngitis and skin infections in children and causes immune complications like rheumatic fever and rheumatoid heart disease (RHD), particularly in developing countries like Ethiopia. The aim of this study was to determine the prevalence, antibiotic resistance pattern, and associated factors of Streptococcus pyogenes among pediatric patients suspected of acute pharyngitis in Sidama Region, Southern Ethiopia.

Methods: A cross-sectional study was conducted on 213 acute pharyngitis suspected pediatric patients from April to September 2022 at Hawassa University Compressive Specialized Hospital and Yirgalem Hospital. Sociodemographic and clinical data were collected using a structured questionnaire. A throat swab was cultured to isolate S. pyogenes, and antimicrobial susceptibility testing was done using standard bacteriological techniques. Data were analyzed using SPSS version 25, and P value of <0.05 was considered as statistically significant.

Result: Out of 213 throat swabs cultured, 22 (10.3%) with 95% CI (6.6-14.6%) were S. pyogenes positive. All isolates of S. pyogenes were sensitive to penicillin and amoxicillin. In contrast, 8 (36.4%) isolates exhibited resistance to tetracycline, 7 (31.8%) to ceftriaxone, 6 (27.3%) to erythromycin, and 5 (22.7%) isolates showed multidrug resistance. The presence of palatal petechiae (P=0.037) and tonsillar swelling or exudate (P=0.007) were significantly associated with S. pyogenes carriage in children suspected of having acute pharyngitis.

Conclusion: In this study, the prevalence of S. pyogenes among children suspected with acute pharyngitis was low compared to other studies. The isolates showed a high level of resistance to commonly used antibiotics. Therefore, the treatment of pediatric acute S. pyogenes pharyngitis should depend on an antimicrobial susceptibility test. Furthermore, evaluation of S. pyogenes pediatric acute pharyngitis risk factors and tracking of antibiotic resistance are crucial in the controlling of pediatric acute S. pyogenes pharyngitis.

Infectious bronchitis virus (IBV) is a significant threat to poultry worldwide, but its status in Ethiopia remains understudied. Thus, this study aimed to detect the virus and associated risk factors in South West Ethiopia. Ninety oropharyngeal swab samples were purposively collected from symptomatic chickens located in Jimma town, Seqa Chekorsa, and Tiro Afeta woredas of the Jimma zone between November 2021 and April 2022 to detect IBV virus by using RT-PCR. A side-by-side questionnaire was administered to assess risk factors. Total RNA was extracted, reverse transcription polymerase chain reaction (RT-PCR) was conducted, and products were visualized under UV light. The overall proportion of IBV was 16.6% (15/90). No statistical association was observed between any of the animal risk factors and the detection of the virus (P=0.57, 0.586, and 1). However, the proportion of birds infected by the virus was higher in males, exotic breeds, and adults compared to females, local breeds, and young birds. Similarly, none of the management risk factors had a significantly different effect on virus detection (P=0.25, 0.09, 0.088, and 0.726). However, improper carcass disposal (OR = 0.43, 95% CI: 0.13-1.4), lack of veterinary services (OR = 2.7, 95% CI: 0.8-8.3), and the presence of wild birds/rodents (OR = 4.4, 95% CI: 0.88-22.3) were associated with increased IBV risk but not cleaning of feeders/drinkers (OR = 1.1, 95% CI: 0.2-4.8). These findings underscore the need for enhanced biosecurity practices and further research to implement informed IBV control strategies in Ethiopia.

The increasing emergence and re-emergence of resistant pathogenic microbes causes a health threat to the human population. Scientists have been striving to find novel bioactive compounds and drugs to overcome these obstacles. This study aimed to characterize mangrove endophytic fungi and evaluate their antibacterial activity. Heritiera littoralis, Rhizophora mucronata, Bruguiera gymnorrhiza, Avicennia marina, and Xylocarpus granatum species were collected from Tudor Creek, Mida Creek, and Gazi Bay. A total of 30 fungal isolates were subjected to molecular identification based on analysis of their ITS gene region. The isolates in the inferred phylogenetic trees were affiliated with the genus Aspergillus. Ethyl acetate and butanol crude extracts of 38.2% of the 76 isolated fungal endophytes and eight mycelia samples were screened for antibacterial activity against Staphylococcus aureus (ATCC 27853), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 25923) using the disc diffusion method. A. marina and R. mucronata harbored the most fungal endophytes that showed the highest antibacterial activity. Seven fungal broth extracts exhibited higher antibacterial activities against the tested microorganisms than the positive control. The minimum inhibitory concentration (MIC) activity for the isolates demonstrated that the ethyl acetate extract of a root endophytic fungal isolate (RC6) (3.31 ± 0.01) of A. marina is a strong inhibitor since it showed significantly lower MIC activity compared to the positive control (3.84 ± 0.00) against Pseudomonas aeruginosa (P < 0.05). Therefore, this study confirms that mangrove species harbor fungal isolates that have antibacterial activity and hence could serve as a novel source of antibiotics. It is recommended that the pure compounds from these extracts be isolated for further bioactivity tests and structural elucidation for consideration as lead molecules in drug discovery. In addition, the genes responsible for the enhanced bioactivity in these isolates can be characterized and bioengineered for pharmaceutical application.

This work was carried out to isolate and perform molecular identification and selection of endophytic nitrogen-fixing bacteria (ENFB) to be utilized as biofertilizer. In this research, nodulous samples of peanuts were collected from inside dyke areas, namely, Phuoc Hung of An Phu, An Giang, Vietnam. Ten colonies were isolated from nutrient agar plates containing YMA's medium. All isolates were rod shaped, Gram negative, and no spore creation. Biochemical tests indicated that they were obligate aerobes, catalase, oxidase, urea hydrolysis, well motile ability, and no nitrate reduction. The salt tolerance observed that most survived at 0.5% and 2% salinity (except Enterobacter cloacae subsp. dissolvens strain LMG 2683), while at 4%, only 3 isolates (Bacillus aryabhattai strain CM44, Enterobacter asburiae strain IIWM-JS-07L, and Bacillus songklensis strain KCa6) and at 5% only, 2 isolates survived, namely, Enterobacter asburiae strain IIWM-JS-07L and Bacillus songklensis strain KCa6. The result showed that most of ten ENFB strains could adapt to the range of 25°C and 45°C (except Enterobacter cloacae subsp. dissolvens strain LMG 2683 and Enterobacter mori strain cjy13 at 25°C). Out of ten isolates, three were finally selected for the next studies, which potentially have N-fixing ability and are utilized as biofertilizer in agricultural cultivation.

Hepatitis B virus (HBV), resistant to several antiviral drugs due to viral genomic mutations, has been reported, which aggravates chronic infection and leads to hepatocellular carcinoma. Therefore, host cellular factors/signaling modulation might be an alternative way of treatment for drug-resistant HBV. Here, we investigated the viral protein expression, replication, and virion production using endoplasmic reticulum (ER) stress-modulating chemicals, tunicamycin (an ER-stress inducer), and salubrinal (an ER-stress inhibitor). We found that ER-stress could be induced by HBV replication in transfected HepG2 cells as well as by tunicamycin as demonstrated by dual luciferase assay. HBV intracellular core-associated DNA quantified by qPCR has been significantly increased by tunicamycin in transfected HepG2 cells. Inversely, intracellular core associated and extracellular particle DNA has been significantly decreased in a dose-dependent manner in salubrinal-treated HepG2 cells transfected with HBV-replicating plasmid pHBI. Similar results were found in stably HBV-expressing hepatoblastoma (HB611) cells treated with salubrinal. However, increased or decreased ER-stress by tunicamycin or salubrinal treatment, respectively, has been confirmed by expression analysis of grp78 using Western blot. In addition, Western blot results demonstrated that the expression of HBV core protein and large HBsAg is increased and decreased by tunicamycin and salubrinal, respectively. In conclusion, the sal-mediated inhibition of the HBV replication and virion production might be due to the simultaneous reduction of core and large HBsAg expression and maintaining the ER homeostasis. These results of HBV replication regulation by modulation of ER-stress dynamics would be useful for designing/identifying anti-HBV drugs targeting cellular signaling pathways.

The extensive use of chemical pesticides and fertilizers in conventional agriculture has raised significant environmental and health issues, including the emergence of resistant pests and pathogens. Plant growth-promoting rhizobacteria (PGPR) present a sustainable alternative, offering dual benefits as biofertilizers and biocontrol agents. This review delves into the mechanisms by which PGPR enhance plant growth, including nutrient solubilization, phytohormone production, and pathogen suppression. PGPR's commercial viability and application, particularly under abiotic stress conditions, are also examined. PGPR improves plant growth directly by enhancing nutrient uptake and producing growth-promoting substances and indirectly by inhibiting phytopathogens through mechanisms such as siderophore production and the secretion of lytic enzymes. Despite their potential, the commercialization of PGPR faces challenges, including strain specificity, formulation stability, and regulatory barriers. The review highlights the need for ongoing research to deepen our understanding of plant-microbe interactions and develop more robust PGPR formulations. Addressing these challenges will be crucial for integrating PGPR into mainstream agricultural practices and reducing reliance on synthetic agrochemicals. The successful adoption of PGPR could lead to more sustainable agricultural practices, promoting healthier crops and ecosystems.

Enteroviral infection is a common cause of aseptic meningitis, herpangina, and hand, foot, and mouth disease in children. Limited data are available on the enteroviral subtypes associated with hospitalization for these conditions in Kazakhstan. We collected cerebrospinal fluid (CSF) and nasopharyngeal swabs (NSW) from children (N = 152, median age = 8 years) hospitalized with symptoms of aseptic meningitis (AM, N = 139) or herpangina (HA, N = 13) disease. We then genotyped enteroviral subtypes associated with AM (n = 50) and HA (n = 9) using next-generation sequencing (NGS) on the viral protein 1 (VP1), followed up by whole-genome sequencing of the isolated viral species. All identified EVs were species B EV, consisting of five echoviruses (E6, E9, E11, E21, and E25) and three coxsackieviruses (CVA9, CVB3, and CVB5) serotypes within the cohort. The most abundant EVs were CVA9 (38.5%), CVB5 (21.5%), and E6 (13.8%). Most HA samples (6/9) were genotyped with coxsackievirus CVA9, while AM was associated with a variety of both echovirus and coxsackievirus serotypes. The results suggest that coxsackievirus CVA9 may be the dominant serotype circulating in the HA population, while AM is more diverse in terms of circulating echovirus and coxsackievirus serotypes. Further studies are needed to determine the clinical implications of these findings and to investigate potential differences in disease severity or outcomes associated with different EV serotypes.

Salmonella spp. is one of the leading causes of foodborne bacterial infections, with major impacts on public health and healthcare system. Salmonella is commonly transmitted via the fecal-to-oral route, and food contaminated with the bacteria (e.g., poultry products) is considered a common source of infection, being a potential risk for public health. The study aims to characterize the antimicrobial resistance- and virulence-associated genes in Salmonella isolates recovered from chicken marketed carcasses (n = 20). The presence of 14 antimicrobial and 23 virulence genes was evaluated using end-point PCR. The antimicrobial genes were detected in the following proportion among the isolates: bla _TEM 100%, dfrA1 and bla _CMY2 90% (n = 18), aadA1 75% (n = 15), sul1 and sul2 50% (n = 10), floR 45% (n = 9), qnrD 20% (n = 4), and aadA2 15% (n = 3). catA, sul3, qnrS, and aac(6')-Ib genes were absent in all isolates. Regarding virulence-associated genes, all Salmonella strains contain invA, fimA, avrA, msgA, sopB, and sopE. The cdtB gene was present in 95% (n = 19) of isolates, whereas spvC and spvB were present in 55% (n = 11). Other virulence genes such as spiC, lpfC, lpfA, and csgA were present in 90% (n = 18) of strains. The presence of antimicrobial and virulence genes in several Salmonella strains in chicken meat suggests the potential pathogenicity of the strains, which is relevant given the possibility of cross-contamination which represents a significant threat to public health.

In the neonatal intensive care unit, adequate nutrition requires various enteral products, including human milk and formula. Human milk is typically fortified to meet increased calorie goals, and infants commonly receive vitamin mixes, iron supplements, and less frequently, thickening agents. We examined the growth of 16 commensal microbes and 10 pathobionts found in the premature infant gut and found that formula, freshly pasteurized milk, and donated banked milk generally increased bacterial growth. Fortification of human milk significantly elevated the growth of all microbes. Supplementation with thickeners or NaCl in general did not stimulate additional growth. Vitamin mix promoted the growth of several commensals, while iron promoted growth of pathobionts. These data indicate that pathobionts in the preterm gut have significant growth advantage with preterm formula, fortified donor milk, and supplemented iron and suggest that the choice of milk and supplements may impact the infant gut microbiota.