Growth Of Bacterial Isolates Research Articles

(128) Characterizing Antibiotic Susceptibility of the Penile Prosthesis Microbiome

Abstract Introduction Inflatable penile prostheses (IPP) are the gold standard treatment for erectile dysfunction refractory to conservative therapies. However, infection remains a significant concern and the presence of microbial biofilms on both infected and non-infected devices has recently been demonstrated. Various antimicrobials are used for prophylaxis intraoperatively and postoperatively. It remains unknown how these antimicrobials affect the growth of bacteria and their associated biofilms. We sought to assess how commonly used antimicrobials influenced growth of bacterial isolates previously isolated from both non-infected and infected devices, obtained during revisional surgery. Objective The goal of this study was to evaluate growth of bacterial isolates previously obtained from non-infected and infected IPPs. Isolates were exposed to single or multi-antibiotic combinations to assess degree of inhibition of bacterial growth. Methods In this IRB-approved study, 35 bacterial isolates had been previously obtained from patients who had been consented for IPP revision or replacement secondary to mechanical failure, pain, or device infection. Bacteria were plated on brain-heart-infusion (BHI) agar plates and allowed to incubate for 48 hours. Standard-sized antibiotic discs were introduced into the grown bacterial colonies consisting of the following single or multi-agent regimens: bacitracin, cefaclor, cephazolin, gentamicin, levofloxacin, trimethoprim-sulfamethoxazole, tobramycin, vancomycin, piperacillin/tazobactam, gentamicin + piperacillin/tazobactam, gentamicin + cephazolin, and gentamicin + vancomycin. Zones of inhibition (ZOI) were measured after placement of the antibiotic discs in the bacterial colonies. Statistics were analyzed with false discovery rate corrected, one-sample t-tests. Quantification of antibiotic resistance was defined as follows: Resistant: ZOI not significantly different from 0 in one sample t-test Susceptible: ZOI significantly greater than 0, but mean is <10mm Highly susceptible: ZOI significantly greater than 0, but mean is 10-20mm Exceptionally susceptible: ZOI significantly greater than 0, but mean is >20mm Taxonomic classification of bacterial isolates was provided by extracting DNA from pure cultures and sequencing the full length 16S rRNA gene using Sanger sequencing, after amplification with two different primer sets to provide overlapping sequence regions. Results Of the antibiotics tested, TMP-SMX was found to have the highest percentage of resistant isolates (54.3%) of the 35 tested, with bacitracin having the second most (40%). Both tobramycin and TMP-SMX had 0.0% of isolates be exceptionally susceptible. Combination piperacillin/tazobactam was found to have the highest percentage of exceptionally susceptible isolates (11.4%). A large majority of isolates were highly susceptible to gentamicin + piperacillin/tazobactam (91.4%), piperacillin/tazobactam (74.3%), gentamicin + cefazolin (74.3%), and levofloxacin (88.6%), while greater than half of isolates were highly susceptible to cefazolin (62.9%) and cefaclor (54.3%)." Conclusions Our results demonstrate that cefaclor or bacitracin prevented growth of bacterial isolates obtained from IPPs explanted for mechanical failure, pain or infection. Further investigation is needed to characterize how intraoperative and postoperative antibiotic influences a symbiotic or dysbiotic community of microbes on the surface of penile prostheses. By better understanding the interactions between microbes, antibiotics and host, novel therapeutics might promote a non-infected, symbiotic microenvironment. Disclosure Yes, this is sponsored by industry/sponsor: Coloplast corporation. Clarification: Industry funding only - investigator initiated and executed study. Any of the authors act as a consultant, employee or shareholder of an industry for: Coloplast, boston scientific.

A host‐derived chimeric peptide protects citrus against Huanglongbing without threatening the native microbial community of the phyllosphere

AbstractIntroductionThe application of host‐derived antibacterial peptides has been highlighted as a potential efficacious and safe tool for the treatment of Huanglongbing (HLB), the most devastating disease of citrus. However, pathogenic bacteria such as HLB‐causing Candidatus liberibacter asiaticus (CLas) often develop resistance against the host antibacterial peptides. We showed that chimeras containing two different host antibacterial peptides not only retain antibacterial activity but also overcome bacterial resistance and enhance plant defence responses. Also, chimeric peptides can have an off‐target impact on the structure and function of plant‐associated microbiomes. However, there is a lack of understanding of the impact of the chimeric peptide therapy on the microbial structure in the citrus phyllosphere while reducing the CLas titre. Here, we aim to evaluate the efficacy of a chimeric peptide (UGK17) to reduce CLas titre, inducing plant defence response and impacting the microbiome associated with the citrus phyllosphere.Material and MethodLeaf samples were collected from orange and grapefruit trees in Texas and identified as old and young leaves according to their maturity. We collected three different types of leaves based on their infection and symptoms: healthy, symptomatic (infected with typical symptoms), and asymptomatic (infected without symptoms). In planta assay was performed by dipping the leaves in the 0, 5 and 25 μM of UGK17 solutions for 48 h. The quantifications of CLas titre and pathogenesis‐related (PR) gene expression were done by quantitative polymerase chain reaction (qPCR) and reverse transcription‐qPCR, respectively. Amplicon sequencing was done to evaluate the impact of UGK17 on individual bacterial community structures. In addition, we performed an ex planta assay to assess the effect of UGK17 on the growth of bacterial isolates including Liberibacter crescens instead of unculturable CLas predominant in the phyllosphere.ResultThe UGK17 treatment reduced the CLas titre in both asymptomatic and symptomatic citrus leaves, regardless of the age of the leaves. The UGK17 application augmented the PR gene expression. In ex planta assay, the growth of L. crescens along with four other strains belonging to the family Rhizobiaceae, was significantly inhibited by the UGK17 while the growth of 74 strains were unaffected. Additionally, there was no statistically significant changes in the microbial community structure with UGK17 treatment.ConclusionOur results suggest that the chimeric peptide therapy is a promising solution to combat HLB by targeting mainly Gram‐negative pathogens and enhancing the plant immune responses without impairing the indigenous microbial community in the citrus phyllosphere.

Effect of carbon nano colloid and its synergism with some antibiotics on Klebsiella pneumonia isolated from UTI of pregnant women

Recently, Klebsiella pneumoniae has become a serious pathogen due to the serious diseases it causes including urinary tract infections especially in pregnant women pneumonia, liver abscess and gastrointestinal. Recent research has tried to find new ways to confront the resistance of these bacteria against different types of antibiotics. Out of 150 isolates that were isolated from urinary tract infections for pregnant women 24 were Klebsiella spp. Molecularly, K. pneumoniae isolates were identified as 16SrRNA of Klebsiella pneumoniae by using polymerase chain reaction. Carbon nano colloid was prepared to investigate the effect of its synergy with antibiotics on the growth of Klebsiella pneumoniae, resistant to a number of antibiotics. The results showed that the highest percentage of the number of bacterial isolates was in the age group 26-30 years. Molecular diagnostics showed that 17 of K. pneumoniae isolates gave a molecular size 274 base pair when PCR was performed using the primer targeting 16SrRNA. Two strains of Klebsiella pneumonia were selected as the most resistant isolates against antibiotics. Multiple concentrations of carbon nanoparticles were synergized with antibiotics and the results showed a broad effect in inhibiting the growth of bacterial isolates. Higher is the concentration of nanoparticles, higher is the sensitivity of Klebsiella pneumonia. The results recorded highest inhibition zoon of 35 mm in Kl.1 isolate and 34 mm in Kl.2 isolate at concentration (1:4) of carbon nanoparticles and Ceftriaxon antibiotic. The concentration of (1:4) of amikacin antibiotic and carbon nanoparticles recorded inhibition zoon (40 and 38 mm) of Kl.1 and Kl.2. The results of the synergistic effect of the antibiotic Gentamicin with carbon nanoparticles showing inhibition zoon diameters were 39 and 28 of the two isolates Kl.1 and Kl.2 respectively.

BIODEGRADATION OF GLYPHOSATE CONTAINING HERBICIDE BY SOIL BACTERIA

Sixty bacterial isolates were isolated from two herbicide contaminated soil farms (Amoyo and University of Ilorin Nursery section both in Kwara State) after enrichment with mineral salt medium (MSM) supplemented with glyphosate containing herbicide. The organophosphorus herbicide efficiently stimulated the growth of bacterial isolates. Bacteria isolated were subjected to screening using varying concentrations of the herbicide ranging from 0.1 to 3% prepared with mineral salt medium. This screening revealed that all the bacterial isolates had biodegradative potential. They however had varying degradative potentials as some had heavy growth while others had only slight growth or no growth on increased concentrations of herbicide. Screening reduces the bacterial populations with growth ranging from 5.0 x 104 to 2.33 x 108 while the number of bacterial isolates reduced from sixty to thirteen. These bacterial isolates were Pseudomonas putida, Bacillus safenis, Lysinibacillus fusiformis, Micrococcus sp., Arthrobacter sp., Aeromonas sp., Bacillus cereus, Flavobacterium sp., Acinetobacter rhizoshaerae, Bacillus pumilus, Achrobacterium sp., Bacillus sp., and Ochrobacterium sp. The increase in viable bacterial counts over the period of 21 days indicated the use of herbicide as carbon source for their various metabolism processes. These bacteria can be recommended as environmentally safer alternatives tools to protect soil from excessive use of glyphosate containing herbicide residues which might contaminate the soil.

Caracterización de bacterias rizosféricas aisladas de suelo cultivado con caña de azúcar en el estado de Tamaulipas, México

The state of Tamaulipas, Mexico, has two important sugar mills, with plantations of sugarcane (Saccharum officinarum L.) of more than 50 years, the objective of the study was the identification and bacterial characterization in the production of indole-3-acetic acid (IAA), the solubilization of phosphorus and plant growth of bacterial isolates from the rhizosphere of sugarcane. The isolation and morphological characterization were in 30 rhizosphere soil samples of the sugarcane variety CP 72-2086 using the Luria-Bertani media, Congo Red Agar and Potato Dextrose Agar. The molecular characterization was with the 16S rRNA gene and the bacterial inoculation consisted of seedlings of the variety CP 72-2086. 121 strains (38 species) were isolated, being Bacillus sp. most frequently, 14 species were positive for phosphorus solubilization: Bacillus sp. (6), Pseudomonas spp. (5), Paenibacillus (2) Streptomyces venezuelae (1) stand out. The greater phosphorus solubilization was Pseudomonas mediterranea (21.6 mm). Nine bacteria showed production close to 5 ppm IAA: Bacillus aryabhattai (6 ppm), Bacillus pumilus (5.8 ppm) and Ensifer adhaerens (5.6 ppm). Bacillus megaterium showed a higher percentage of chlorophyll and foliar nitrogen. In the present analysis, 38 bacterial species associated with the rhizosphere of the sugarcane variety CP 72-2086 were identified, so these results showed the potential to select native bacteria that have the ability to stimulate plant growth of the variety CP 72-2086.

The Effect of Callyspongia Biru Antibacterial Extract Concentration Towards the growth of Bacterial Isolates of Eucheuma cottonii Seaweed with Ice-ice Disease

This research was conducted at the Biology Education Laboratory, Faculty of Teacher Training and Educational Sciences, Nusa Cendana University, with the aim of knowing the effect of the concentration of the antibacterial extract of Callyspongia biru on the growth of bacteria that caused Ice-ice disease. The method used in this study was an experimental method, with a Completely Randomized Design (CRD) consisting of 4 treatments (concentration of Callyspongia blue extract of 10%, 20%, 30% and 40%) with 3 times repetition. Therefore, the total treatment units were 12 units. The parameter that has been measured in this study was the diameter of the inhibition zone. The inhibition zone diameter data was then analyzed by using one-way ANOVA with the Tukay method.If Fcount is greater than Ftable then it would be tested further using Honest Reality Difference test at 5% significant level. The result showed that the different concentrations of Callyspongia blue extract gave significantly different effects on the growth of bacterial isolates from seaweed Eucheuma cottonii with Ice-ice disease. At a concentration of 40%, Callyspongia biru extract showed the strongest average inhibition of 27.67 mm.

DAYA HAMBAT EKSTRAK CALLYSPONGIA SP. TERHADAP BAKTERI DARI Eucheuma Cottoni BERPENYAKIT Ice-Ice

Callyspongia sp. is one type of sea sponge that produces secondary metabolites in the form of steroids, alkaloids, flavonoids, and terpenoids which can be used as antibacterial agents. This reseach aims to determine whether or not there is an inhibitory power of sea sponge extract Callyspongia sp. on the growth of bacterial isolates on Eucheuma cottonii seaweed that is infected by ice-ice disease. This type of research is an experimental laboratory. Extract of Callyspongia sp. is the result of Callyspongia sp. extraction which has been dried and then macerated using a polar ethanol solvent. Inhibition test with the modified Kirby-Bauer method used wells to measure the zone of inhibition formed by the extract of the Callyspongia sp. The test was carried out to observe the presence or absence of an inhibition zone of Callyspongia sp. extract against bacterial isolates (Isolates I, II and III) that is infected by seaweed that is infected by ice-ice disease after 24 hours of incubation. The results showed that an inhibition zone was formed in bacterial isolates. Treatment with extracts of Callyspongia sp. shows the diameter of the highest inhibition zone that is 16.67 mm which is classified as a strong inhibitory force, so that Callysponia sp. extract has the potential in overcoming ice-ice in Eucheuma cottonii seaweed.

Production and Characterization of Exopolysaccharide extracted from bacteria isolated in homemade and packed Idli batter

Diverse exopolysaccharide (EPS)-producing isolates were isolated from an Indian acidic fermented food (Idli) based on the colony morphology. Lactic acid bacteria are non-pathogenic organism widely distributed in nature typically involved in a large number of spontaneous food fermentation. One of the EPS-producing micro flora was selected for further characterization using FT-IR, SEM, TGA and XRD analysis. The effect of pH, salt and temperature on the yellow pigment were studied and these parameters are gently influence the growth of bacterial isolates. In pH the maximum yield of biomass were obtained at pH (8) . In temperature maximum yield at 40 C and in salt concentration (Nacl) the maximum yield were obtained with 2%. Effect of total phenolic content, antioxidant activity and reducing power assay influence the growth biomass of the bacteria. In the structural characterization, the FT-IR spectroscopy revealed the α-d-glucose nature of the EPS. The SEM showed smooth surfaces and compact structure. TGA results showed higher degradation temperature of 272.01̊ C. XRD analysis proved the 33.4% crystalline nature of the EPS. All the above characteristics of the EPS produced by L. lactis showed that the EPS is of a good-quality polysaccharide with potential applications in the food industry.

Sterility Assessment of Some Face Masks for Public Use During COVID-19 Pandemic in Lagos, Nigeria

Globally, the use of face masks is one of the non-pharmaceutical interventions recommended as a method of preventing spread of SARS-CoV-2. Lagos State was an epicenter of COVID-19 and as such, the State Government made the use of facemasks mandatory while in the public and social gatherings. Due to the alarming rate of spread of COVID-19 pandemic, shortage of masks and respirators has been observed and reported globally. This has led to production and use of different types of facemasks including locally made facemasks of different fabrics. A total of 400 consisting of 200 made of local fabrics, 100 imported face/surgical masks and 100 N95 respirators were selected from different sources in Lagos State between May 2020 and November 2020. Samples were immersed aseptically into conical flask containing 100ml Nutrient broth and incubated 18-24hrs. The broth culture was sub-cultured onto Sabouroid Dextrose Agar in duplicates. One of the SDA was incubated at room temperature and the other at 37°C. Blood, Chocolate and MacConkey agar plates were also inoculated and incubated at 37°C for 18-24 hrs. Isolates were identified using phenotypic identification methods. Of the total 400 samples, 346 (86.5%) had no bacterial or fungal growth while 44 (11.0%) had one bacterial isolate and 10 (2.5%) had mixed growth of bacterial isolates. Of the 200 locally-made face masks, 39 (19.5%) had one bacterial isolate and 9 (4.5%) had two bacterial isolates and 5 (2.5%) had fungal isolates while out of the 100 imported surgical masks, only 4 (4.0%) had one bacterial isolate and one (1.0%) had mixed growth of bacterial isolates. One (1.0%) of the imported N95 respirator had only one bacterial isolate <i>(Lactobacilli spp)</i>. Generally, the isolated bacteria were <i>Staphylococcus aureus, Coagulase negative Staphylococcus, Escherichia coli, Klebsiella species and Lactobacilli species while fungal isolates were Candida albicans and Aspergillus fumigatus</i>. The locally-made face masks were contaminated with both bacterial and fungal isolates. Face masks with no bacterial or fungal growth had a p-value of 0.02 and it is statistically significant in terms of the face masks tested in this study. Face masks with one bacterial isolate had a p value of 0.35 and those mixed growth of two different bacterial and fungal isolates had a p value of 0.36 which indicated a non-statistically significant results of the face mask tested in these categories. Locally made face masks were more contaminated with single or mixed bacterial and fungal agents. Cautionary use of the masks is recommended.

Evaluate the efficacy of Probiotic Lactobacilli on growth and biofilm formation in Streptococcus mutans isolated from gingivitis

The present study aimed to assess the antibacterial effects of Probiotic Lactobacilli against Streptococcus mutans isolates. A total of 13/52 (25%) S. mutans isolates were collected from patients suffering from gingivitis, which were identified using morphological characteristics, biochemical tests and PCR technique. Micro titer plate method was used to detect the biofilm formation in tested bacterial isolates by measuring optical density (OD) using ELISA reader at a wavelength 640 nm. The results revealed that only 10/13 (77%) isolates produced the biofilm. Based on the results obtained in this study, the isolates were classified according to their ability to the biofilm formation as follows: the isolates with thick biofilm (OD ≥ 0.300 nm), the isolates with moderate biofilm (OD 0.2-0.3 nm), the isolates with thin biofilm (OD 0.1-0.2 nm) and Non-productive isolates of biofilm (OD < 0.1 nm). On the other hand, the agar well diffusion method was used to evaluate the effectiveness of Probiotic Lactobacilli against the growth of bacterial isolates by measuring the inhibition zones around the wells containing of probiotics (50, 100 mg/ml and stock). The results indicate that inhibition zones of the tested isolates were weak at 50 mg/ml, moderate at 100 mg/ml and strong at stock solution. A modified crystal violet test in well micro-titer plates was used to detect the ability of isolates to the biofilm formation after treatment with various concentrations of Probiotic Lactobacilli by measuring optical density (OD). The results indicate a decrease in the ability of the tested isolates to the biofilm formation compared to control where the isolates treated with probiotics at 50 mg/ml formed a strong biofilm (OD 0.300 - 0.341 nm) and the isolates treated with probiotics at 100 mg/ml formed moderate biofilm (OD 0.209 - 0.263 nm), while the isolates treated with the stock solution of probiotics formed a thin biofilm (OD 0.144 - 0.198 nm). In conclusion, the results of the current study indicate that the Probiotic Lactobacilli have inhibitory effect on growth and biofilm formation in Streptococcus mutans isolates and the antibacterial activity of Probiotic Lactobacilli is increased with increasing concentration.

Plasmid Profiling and Effect of Different Physiological Parameters on the Chromium Reduction Potential of Microbes

Chromium is toxic for both human and aquatic life. It is recommended to eradicate from wastewaters or to alter its oxidation state to less toxic level The purpose of current research was to isolate heavy metal (Cr) resistant bacteria from different industrial effluents (soil and waste water), to determine their potential for chromium reduction (CRP) at different parameters (time period, pH, temperature and concentrations of chromium) and to determine the plasmid profiles of Cr (VI) resistant bacterial isolates. The growth of chromium resistant bacteria was determined by checking the influence of pH, concentration of chromium, time period and temperature on isolates using UV spectrophotometer, while chromium reduction potential was also investigated using Deleo and Ehrlich method. Plasmid profiling was performed and analyzed using agarose gel electrophoresis (0.8%) to determine the number, size and relationship of plasmid with heavy metal resistance. Results showed that the identified bacterial isolates (S. aureus and S. epidermidis) were resistant to heavy metal (Cr) confirmed by resistance profiling. The maximum growth of bacterial isolate was recorded after 24-hour incubation period (1.154), at pH 8 (1.512), temperature 37ºC (1.615) and 500 µg/mL chromium concentration (1.978), while suitable conditions observed for chromium reduction potential was 24-hour incubation period (57%), pH 7 (62.6%), temperature 30ºC (60%), and 500 µg/mL concentration of chromium (60%). The plasmid profiles revealed that plasmid were randomly distributed among the bacterial isolates with average plasmid number (2.9) ranging from 0-5 and molecular size (100-12000bps). Overall, no defined relationship was observed among resistance pattern and plasmid mediated profiles.

Phylogenetic characterization and screening of halophilic bacteria from Algerian salt lake for the production of biosurfactant and enzymes

Environments containing significant concentration of NaCl such as salt lakes harbor extremophiles microorganisms which have a great biotechnology interest. To explore the diversity of Bacteria in Chott Tinsilt (Algeria), an isolation program was performed. Water samples were collected from the saltern during the pre-salt harvesting phase. This Chott is high in salt (22.47% (w/v). Seven halophiles Bacteria were selected for further characterization. The isolated strains were able to grow optimally in media with 10–25% (w/v) total salts. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. It showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Planococcus and Halobacillus genera with less than 98% of similarity with their closest phylogenetic relative. The halophilic bacterial isolates were also characterized for the production of biosurfactant and industrially important enzymes. Most isolates produced hydrolases and biosurfactants at high salt concentration. In fact, this is the first report on bacterial strains (A4 and B4) which were a good biosurfactant and coagulase producer at 20% and 25% ((w/v)) NaCl. In addition, the biosurfactant produced by the strain B4 at high salinity (25%) was also stable at high temperature (30-100°C) and high alkalinity (pH 11).

Microplastics in a dam lake in Turkey: type, mesh size effect, and bacterial biofilm communities.

The evaluation of microplastic (MP) pollution has been drawing attention for the last decades. MP pollution has been studied widely in marine environments, but limited data exists for freshwater ecosystems on potential source and transport of MPs. The type, shape, plastic components, and the color of the MPs were investigated using various-mesh-sizes (300 and 100μm) nets in four sampling stations of Süreyyabey Dam Lake in Turkey. The growth of bacterial isolates on the MPs surface and surrounding water was also investigated. The type of the MPs and the interaction between the mesh size and the type of the MPs showed significant differences (p< 0.05). Fibers were found to be the most abundant particle type constituting 45% and 80% of the total MPs found in 330-μm and 100-μm mesh sizes, respectively. In total the observed MP abundance in the dam lake was 5.25 particles m-3, and 4.09 particles m-3 was observed for 100-μm and 330-μm mesh sizes, respectively. The color of the identified microplastics showed variations among microplastic types; however, the dominant color was transparent in each net. The main plastic components of the MPs are polyethylene terephthalate, polyvinyl chloride, polystyrene, polyethylene, and polypropylene. The microbial community mainly consists of potentially pathogenic strains such as Escherichia coli, Enterococcus faecalis, and Acinetobacter baumanii complex. The current study could contribute valuable background information both for MP pollution and for biofilm composition in a dam. However, the surface of the MPs and biofilm formation should be investigated urgently to understand the vector potential of MPs.

The inhibitory activity of plant extracts (Mentha Citrato L. and Citrus aurantium L.) towards some bacteria strains isolated from inflamed gums

This study was conducted in Salahaldin for the period from 15/9/2018 to 15/3/2019, to study the inhibitory activity of aqueous and alcoholic (Eth,Meth) extract of Mentha Citrato L. And Citrus aurantium L plants by agar well diffusion method on some bacterial causing gingivitis . including Staphylococcus aureus, Streptococcus faecalis and Klebsiella pneumonia, were isolated. The results showed that alcohol extracts had a high inhibitory effect on the growth of the bacterial species under study compared to the aqueous extracts. These bacterial isolates were primarily sensitive to the methanolic and ethanolic extract, followed by the hot aqueous extract .&#x0D; The study showed that Mentha Citrato L extract was more effective in inhibiting the growth of bacterial isolates compared to the extracts of the Citrus aurantium L. The inhibitory efficacy of these extracts increased with the concentration of the extract. The concentration was 100 (mg / ml) had a higher inhibitory value than the total concentration Study 20 and 60 (mg / ml) .

Assessment of the Petroleum Oil Degradation Capacity of Indigenous Bacterial Species Isolated from Petroleum Oil-Contaminated Soil

Petroleum hydrocarbons are highly toxic to plants, animals, and humans and are carcinogenic effects to plants, animals, and humans. The present study is focused to enhance the degradation of petroleum hydrocarbons using potential indigenous bacterial isolates. Bacteria were isolated from different petroleum oil-contaminated sites and characterized. Bacterial growth was evaluated under different physico-chemical parameters. The petroleum hydrocarbon degradation potentiality was assessed using GC–MS analysis. Forty-nine bacterial isolates were screened; only three isolates (ALK-14, ALK-16, and ALK-23) have good potential to degrade petroleum hydrocarbons and were identified as Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23, respectively, on the basis of morphology, biochemical characterization, and 16S rRNA sequencing. Optimum growth of Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23 occurred at pH 7, 6, and 6, respectively. Petroleum oil concentration found suitable for growth of selected bacterial isolates Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23 were 4%, 8%, and 4% (v/v), respectively. Among different nitrogen sources, ammonium nitrate was found suitable source for the maximum growth of Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16 at the concentration of 0.15 and 0.2%, respectively, and sodium nitrate for Enterobacter species ALK-23 at the concentration of 0.2%. All bacterial isolates showed maximum growth at 30 °C temperature. Synergistic effect on the growth of bacterial isolates under favourable conditions increased up to 11–28%. GC–MS analysis indicated that the hydrocarbon compounds in the range of C20–C44 were present in petrol. Maximum hydrocarbon degradation by Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23 was 11.65%, 8.11%, and 5.59%, respectively. The degradation of docosane 11-decyl, hexatriacontane, and eicosane by Alcaligenes species ALK-14 was 100%, 60%, and 48.8%, respectively. The degradation of docosane 11-decyl by, Bacillus methylotrophicus ALK-16, was 80%. Degradation of hexatriacontane by Enterobacter species ALK-23 was 31%. Further understanding of the metabolic processes of these organisms on crude oil hydrocarbons degradation will increase possibilities to develop strategies for removing crude oil pollutants from oil-impacted environments.

Influence of humic acid, iron and copper on microbial degradation of fungicide Carbendazim

Abstract Carbendazim (CBZ) is a systemic fungicide utilized for the control fungal diseases in forestry and agricultural crops. Its severe toxicity and residual nature mandated its removal and biodegradation by biological, eco-friendly and sustainable methods. Towards this direction, we searched for CBZ utilizing bacterial strains from the agricultural soils. Based on morphological, biochemical and molecular characterisation the isolates were identified as Streptomyces sp. CB1, Bacillus subtilis CB2, Pseudomonas aeruginosa CB3 and Rhizobium leguminosarum CB4. The effect of CBZ on isolates in the presence and absence of Fe(II), Cu(II) and humic acid was determined. It was found that humic acid supplementation resulted in enhanced and extended growth of bacterial isolates. Among the four isolates, P. aeruginosa CB3 exhibited highest CBZ degradation followed capability by B. subtilis CB2, Streptomyces sp. CB1 and R. leguminosarum CB4. Supplementation with Cu(II) ions resulted in higher degradation of CBZ. However, humic acid was only moderately effective, whereas Fe(II) failed to show any appreciable increase in CBZ degradation by bacterial isolates. Our study suggests that CBZ adapted bacterial strains can offer a biologically and sustainable solution for bioremediation of contaminated agricultural fields and reservoir sites.

Isolation and Identification of Antagonistic Bacterium against a Pathogens of Bacterial Tuber Rot of Amorphophallus muelleri

Rhizosphere bacteria have the ability to protect the host plants from the infection of pathogenic microorganisms. This study aimed to identify rhizosphere bacteria that were capable of inhibiting the growth of bacterial isolates that cause tuber rot of Amorphophallus muelleri . Rhizosphere bacteria were isolated using Nutrient Agar medium by pour plate method. Isolates were subjected to antagonistic assay against several bacterial isolates from the rotten tuber of A. muelleri using dual culture method. The potential isolate was identified based on 16S rDNA sequence. Isolate R7 showed the strongest inhibition to the growth of bacterial isolates from rotten tuber with an inhibition zone diameter of 19.66 mm. The 16S rDNA sequence of isolate R7 R7 was 99.7% similar to Delftia tsuruhatensis PCL1755. The isolate was potential to be developed as phytopathogen control agent. Keywords: Amorphophallus , antagonistic bacteria, rhizosphere bacteria, rotten tuber, 16S rDNA .

Surfactant Mediated Biodegradation of Aromatic Hydrocarbons Using Rhamnolipid Producing Bacterial Isolate

Aromatic hydrocarbons (toluene and xylene) are highly water soluble and their contamination with groundwater is a serious issue. Hydrocarbons are growth substrates for microorganisms which use them as a sole source of carbon and energy. Surfactants increase the solubility and dissolution of hydrocarbons thus making them susceptible to degradation. In this study, biodegradation of toluene and xylene using a soil bacterium was evaluated in the presence of chemical surfactant. The colonies that were tested positive for xylene and toluene degradation in the primary screening were analyzed by 16s rRNA sequencing and identified as <i>Bacillus Cereus</i>. The presence of chemical surfactant enhanced the growth of bacterial isolate and its bioremediation activity indicated the possible role of the tween in bioremediation process. It was observed that pH of the medium has reached near neutral from initial pH of 8.2 at the end of 21 days cultivation period. Addition of hydrocarbons in the mineral salt medium (MSM) has enhanced the bacterial growth as confirmed by increasing optical density throughout the cultivation period. Increase in protein content of bacterial isolate indicated its metabolic activity in the presence of hydrocarbons. Similarly, increase in the rhamnolipid concentration of <i>B. cereus</i> grown in MSM along with hydrocarbons and chemical surfactant indicated the role of rhamnolipids during the biodegradation of xylene and toluene.

Comparison of temperature effects on the in vitro growth and disease development in potato tubers inoculated with bacteria Pectobacterium atrosepticum, P carotovorum subsp. carotovorum and Dickeya solani

AbstractThe relationship between the rate of in vitro growth of bacterial isolates of Pectobacterium atrosepticum, P. carotovorum subsp. carotovorum and Dickeya solani and their pathogenicity was investigated in tubers of two potato cultivars at four temperatures ranging from 18°C to 30°C. The rate of in vitro growth was highly positively correlated with the number of rotted tubers (r ranged from 0.91 to 0.93) and with the weight of macerated potato tissue, which, however, was only found for P. carotovorum and D. solani (r = 0.76; r = 0.91, respectively) and not for P. atrosepticum. The weight of macerated tissue increased with the temperature, but significant differences between species of bacteria were observed only at 26°C and above, at which temperatures D. solani was the most aggressive, followed by P. carotovorum and P. atrosepticum. Almost all potato tubers inoculated with bacteria showed symptoms of soft rot at 26°C and 30°C, but the number of rotting tubers at lower temperatures (22°C and 18°C) decreased significantly. The lowest disease incidence, 11% of tubers with symptoms, was observed for the D. solani and cultivar Sonda at 18°C, what was also confirmed in a separate experiment with tubers from four potato cultivars inoculated with the highly aggressive isolate of D. solani. At temperatures from 18°C to 30°C, the differences in disease severity between potato cultivars with various resistance to bacteria increased in line with temperature, while the differences in disease incidence decreased.

Evaluation of some chemical disinfectant formulations against Pseudomonas and Staphylococcus species from poultry and poultry environment

Introduction: Diskol, Iodasteryl and Morigad are disinfectant formulations commonly used in the poultry industry in Nigeria to prevent infections of birds. Aim: The formulations were evaluated for effectiveness in controlling the growth of bacterial isolates from poultry and poultry environment. Materials and Methods: The bacteria were isolated from water, feed, litter materials, and cloacae swabs, and were identified using the Analytical Profile Index kits. The disinfectant evaluation was carried out using the kill kinetics method at 0.5X, 1X and 1.5X the manufacturer’s recommended dilutions. Results: The pseudomonads had percentage occurrence of Pseudomonas putida (25) &gt; P. mendocina (20) &gt; P. aeruginosa (15), P. stutzeri (15), P. fluorescens (15) &gt; P. shigelliodes (10), while the staphylococci had Staphylococcus lentus (78.26) &gt; S. sciuri (13.04) &gt; S. aureus (8.70). Diskol and Morigad recorded 8 log1010 reduction (i.e. 100% kill) at the 3 concentrations against all the Pseudomonas isolates at 10 min contact time but were only able to achieve same at 1X and 1.5X against the staphylococci. At 0.5X, however, both Diskol and Morigad were only able to achieve 8 log10 reduction (100% kill) of all Staphylococcus sp. at 30 min except against S. sciuri SN3 where Diskol achieved same record at 10 min. The best performances of Iodasteryl were less than 100% kill even at 8log 10 reduction against P. putida FaF12, P. mendocina FaW48, P. stutzeri FaM35, and P. shigelliodes FbM36 at 1.5X and 60 min and 7.99log 10 reduction at 1.5X and 60 min against S. lentus SN1, S. lentus SN2, S. sciuri SN3, S. sciuri SN4 and S. aureus SM2. All disinfectants demonstrated increasing activity with increase in time and concentration. Conclusion: The study indicated the potential of the disinfectants in elimination of some bacteria of public health significance thus justifying their use in the control of poultry infections.