Spread Plate Technique Research Articles

Scaled-up Processes for the Preparation of Enhanced Antibacterial ZnO-Menthol, ZnO-Chitosan, and ZnO-Triclosan Flake/Spine-like Nanocomposites, and their Biocompatibility and Toxicity Studies

Introduction: Nanomaterials, especially their biocompatibilities and toxicities, have not been studied and their integration in real applications is still limited. Method: This paper addresses this gap by focusing on the development of antibacterial nanomaterials by combining flake/spinal ZnO nanostructures with organic antibacterial agents (menthol, chitosan, and triclosan). We systematically study their biocompatibility and toxicity, intending to apply them practically on fabric surfaces. Result: Based on the known photocatalytic and antibacterial properties of ZnO, our hypothesis suggests that the unique flake/spine ZnO nanostructures can further improve the antibacterial efficacy through induced mechanistic approaches. The synergistic effect achieved by combining ZnO with menthol, chitosan, and triclosan improves the overall bactericidal ability. XRD, XRF, FTIR, SEM, and UV-visible spectroscopy are used to characterize the nanocomposites. The antibacterial properties of the modified fabrics are tested using standard spread plate techniques. Biocompatibility and toxicity studies using a mouse model provide a comprehensive picture of the safety profile. Conclusion: This work advances the understanding of antibacterial nanomaterials, and paves the way for their wider manufacturing and practical use in textiles, meeting the industrial needs of antimicrobial clothing and wound dressings.

Protease enzymes from Pseudomonas fluorescens and Pseudomonas aeruginosa as potential bioagents against Pratylenchus loosi

Root lesion nematode of tea (Pratylenchus loosi) is one of the most dangerous and destructive pests in all areas of the world where tea grows. Rhizobacteria with nematicidal properties were screened using the soils of root lesion nematode-infected tea fields located in Guilan province, Iran. Effective bacteria were identified based on molecular and biochemical methods. Protease enzyme production was investigated on skim milk agar (1%) medium. The effects of temperature and pH on the amount of protease production by bacteria were investigated. Three protease inhibitors, namely PMSF, EDTA and 1,10-phenanthroline, were investigated. In total, 150 bacterial strains were isolated from tea rhizosphere using the spread-plating technique and nutrient agar medium, of which four bacterial isolates of Pseudomonas spp. had nematicidal properties in the range of 84.98% to 95.24%. Two of the bacterial isolates, RH25 (Pseudomonas aeruginosa) and RH37 (Pseudomonas fluorescens), had the largest clear zone of proteolysis on skim milk agar and were subjected to various biochemical tests. The influences of time (1 to 120 h), temperature (22 to 37°C) and pH (7.0 to 8.5) were investigated in the production of protease. The highest enzyme production was obtained from growing RH37 and RH25 on mineral medium when incubated at temperatures of 26°C and 30°C for 72 and 96 h and at initial pH values of 7.2 and 7.6, respectively. Proteases obtained from RH37 (P. fluorescens) belonged to the metalloprotease and serine protease families and the one produced by RH25 (P. aeruginosa) was a metalloprotease. According to the results of this research, the most effective control mechanism of these bacteria against nematodes is the production of bacterial protease. This mechanism can be exploited to control nematodes.

Antibacterial activity of pigment extracted from bacteria isolated from soil samples

The purpose of this study was to evaluate antibacterial activity of pigment extracted from bacteria, isolated from soil samples. During the study, 20 soil samples were collected from different areas (forest, agriculture fields, river sides and dumping sites) of Kathmandu and Lalitpur districts which were processed for isolation of pigment producing bacteria by spread plate technique. The pigmented bacterial isolates were identified and enriched in nutrient broth. Then, pigment was extracted in 95% methanol as solvent, which was further characterized using UV-Vis Spectrophotometric and TLC analysis. The obtained crude pigment extract was processed to carry out the antimicrobial susceptibility assay using agar well diffusion method. Out of 13 total pigmented bacteria isolates, four different colored pigmented bacterial isolates (S4O, S11Y, S14P and S17G) which produced efficient pigment on nutrient agar were chosen and they were further processed. Among these isolates, S4O was identified as Staphylococcus aureus, S11Y was identified as Micrococcus luteus, S14P was identified as Micrococcus roseus and S17G was identified as Pseudomonas aeruginosa respectively. On characterization using UV-Vis Spectrophotometric and TLC analysis, the pigment extracted from isolates S4O, S11Y and S14P were found to be Carotenoids and from isolate S17G was found to be Pyocyanin in nature. The maximum antibacterial activity was shown against Staphylococcus aureus from all the four pigments extracts. The green color pigment extract from isolate S17G was found to be most effective against all the Gram-positive and Gram-negative test bacteria. This study suggests that these pigment extracts from pigmented bacteria may have beneficial antibacterial roles that can be exploited in controlling unwanted bacterial growth.

TOTAL BACTERIA, COLIFORMS AND NON-COLIFORMS IN THE MILK OF ETAWA CROSSBREED IN SINGAPADU KALER VILLAGE, SUKAWATI DISTRICT, GIANYAR REGENCY

Etawa crossbreed goat's milk is a source of animal protein that is increasingly in demand by the public because it has very high nutritional value. Besides its nutritional value, milk is also a good medium for the growth of various types of microorganisms. This study aims to determine the total bacteria, coliforms and non-coliforms in Etawa crossbreed goat milk. The data taken is milk from the entire population of Etawa crossbreed goats that are currently lactating. This research is a type of observational research with a purposive sampling method. Counting total bacteria, coliforms and non-coliforms using the spread plate technique. The data obtained were analyzed descriptively by counting the number of bacteria in the culture media. The results showed that the total bacteria average was 3 x 10⁶ ± 1 x 10⁶ cfu/ml, coliforms were 2 x 10³ ± 1 x 10³ cfu/ml and non-coliforms were 2.2 x 10⁶ ± 2.5 x 10⁶ cfu/ml. Based on the research results, it can be concluded that the microbial contamination limit does not meet SNI. It is necessary to improve the cleanliness of cages and livestock so that bacterial contamination in milk can be reduced and further tests need to be carried out on the types of pathogenic and zoonotic bacteria present in the milk of Etawa crossbreed goats in Singapadu Kaler Village, Sukawati District, Gianyar Regency

Molecular Characterization and Tolerance Potential of Culturable Crude Oil-Degrading Microbes in Santa-Barbara River, Bayelsa State, Nigeria

There has been chronic contamination of the surrounding aquatic and terrestrial environments in the Niger Delta region of Nigeria due to the enormous activities of crude oil exploration. This study aimed to characterize and assess the crude oil tolerance potential of indigenous microbes from crude oil spills in Santa Barbara River, Bayelsa State, Nigeria, that could serve as potential consortia for bioremediation of the crude oil spills. Total crude oil hydrocarbon-utilizing bacteria count (THUBC) and total crude oil hydrocarbon-utilizing fungi count (THUFC) in the samples were determined with a culture-dependent spread plate technique. Bacterial and fungal isolates were characterised using standard phenotypic and 16S/Internal Transcribed Spacer region rRNA gene sequencing techniques, respectively. The tolerance of autochthonous bacterial isolates to different concentrations of crude oil was subsequently determined. THUBC and THUFC in crude oil-polluted water samples ranged from 1.88 log10 CFU/ml to 2.74 log10 CFU/ml and from 0.00 log10 CFU/ml to 1.70 log10 CFU/ml, respectively. Representative strains of Proteus mirabilis, Bacillus subtilis, Pseudomonas aeruginosa, Micrococcus luteus and Aspergillus flavus isolates obtained from crude oil-polluted water samples were deposited in the GenBank (NCBI) under accession numbers OQ969924, OQ969951, OQ969987, OQ970009 and OQ975908. Proteus mirabilis, Pseudomonas aeruginosa and Aspergillus flavus demonstrated the most significant tolerance to crude oil pollutants (minimum crude oil inhibitory concentrations (MIC) = 80%) followed by Bacillus subtilis and Micrococcus luteus (MIC= 40%). The findings from this study are pointers to the potential role of the microbial isolates as bioremediation consortia to remediate the polluted Santa Barbara River.

Bacteriological analysis of suya meat sold in nkwo market of okija and the associated health implications

This research work was done to ascertain the bacterial load of Suya sold in Nkwo market of Okija town in Ihiala LGA of Anambra State. It was also done to reveal the health implication of the suya. Three samples of Suya were randomly collected from suya sellers within the market. The samples were analyzed microbiologically using spread plate technique. The bacterial isolates were identified. The isolates were identified as Staphylococcus spp., Escherichia coli and Klebsiella spp. The total bacterial count for the isolates were 2.5 x 10³, 4.3 x 104 and 5.4 x 10³ respectively. For the coliform count, 0.5 x103, 3.0 x 103 and 1.2 x 103 were identified. The presence of Staphylococcus is associated with cross contamination from meat handlers during processing, the presence of Escherichia coli is probably due to use of contaminated water during washing of raw meat while Klebsiella spp. is most likely transmitted from the hands of meat workers. This calls for improved production hygiene and public health awareness. Education and awareness campaign should be organized for the Suya seller on the proper hygienic practices to adopt during suya processing.

Isolation of Plastic Degrading Fungi from Plastic Dumped Sites

Plastics that are biodegradable can be considered environment friendly, they have an increasing range of potential application and are driven by the growing use of plastics in packaging. In this study, the biodegradation of Low-density Polyethylene films was analyzed about 1 month of incubation in liquid culture method. In this investigation, soil samples were collected from two different plastic dumped sites and the fungus were isolated through spread plate technique from diluted soil samples. Among the six fungal isolates were tested for checking its degradation ability of plastics. This study showed the cultural analysis for its ability to adhere and grow on the LDPE films. The activity enzyme produced by these fungal isolates was responsible for the biodegradation. Isolating plastic-degrading fungi from plastic dumped sites serves several important purposes, Understanding the role of fungi in plastic degradation can shed light on the ecological impact of plastic pollution on ecosystems. It can also help identify potential solutions to mitigate this impact. Isolating fungi from plastic dumped sites contributes to the exploration of microbial biodiversity in these environments. It can lead to the discovery of novel fungal species with unique abilities to degrade plastic.

Incidence of Bacterial Contaminants in Fermented Milk (Nono/Kindirmo) Sold By Fulani Women to Consumers in Wukari Metropolis, Taraba State, Nigeria

A study was conducted to investigate contaminants in fermented milk sold by Fulani women in Wukari, Nigeria. Fifteen milk samples were obtained from five different sales points (A, B, C, D, and E) for analysis. The Standard Plate Count method was employed to detect contaminants, with spread plate techniques isolating bacteria. The total aerobic bacteria count on nutrient agar plates was found on sample 2 of sales point D with a bacteria count of 3.3 x 106. The total aerobic bacteria count on Manittol salt agar plates was found on sample 2 of sales point D with a bacteria count of 2.4×106. The highest bacterial growth was staphylococcus aureus with 73.33%. The least bacterial growths was Escherichia coli and Pseudomonas aeruginosa with 13.33% respectively. Sample 1 of sales point A, samples 1 and 2 of sales point D and sample 3 of sales point E show bacteria growth on the Mannitol salt agar plate, while the other samples shows no growth. Also on a Nutrient agar plate, sample 1, 2, and 3 of sales point A, sample 3 of sales B, sample 3 of sales point C, and sample 2 of sales point D were negative, while the other samples were positive. It can be concluded that the high incidence of contamination with bacteria in nono could be attributed to the unhygienic milking process and post-contamination after pasteurization and during sales.

Bacterial Diversity of the Silverleaf Whitefly, Bemisia tabaci (Gennadius), Collected on Jasmine and Chrysanthemum

The adults and nymphs of Bemisia tabaci were collected on jasmine and chrysanthemum during 2021-2023 from Southern part of Karnataka, India. Bacterial colonies were isolated from adults and nymphs of B. tabaci using spread-plate technique and identified through 16srRNA sequencing. The B. tabaci collected on jasmine harboured more number of bacteria (8 species) than chrysanthemum (5 species). Most bacterial species isolated from B. tabaci, collected on jasmine and chrysanthemum, belonged to the phylum Bacillota (62.5 and 60 percent). Similarly, Bacilli, Bacillales and Bacillaceae were the dominant class, order and family of the bacteria associated with B. tabaci. Nymphs harboured higher number of bacteria than adults in both jasmine (62.5 and 33.5 percent, respectively) and chrysanthemum (60 and 40 percent, respectively). Bacillus cereus and B. pumilus were commonly found species from the nymphs and adults of B. tabaci on jasmine. When insect hosts shifted, change in the nutrition and defence system of the host plant influences the bacterial diversity of the insect.

Bacteriological Tracing of Haemophilus influenzae in Some Public Toilet Seat Bowls of Port Harcourt

The study aimed at tracing Haemophilus influenzae on toilet seat bowls of some public toilets in Port Harcourt. The toilets were coded DER, TYU, AFR for park, market and hospital toilets respectively, for the purpose of the study. Swabs were collected aseptically from the toilet seat bowls, with a moistened swab stick, and then introduced into a freshly prepared sterile peptone water for viability of the Haemophilus influenza isolates. Thereafter, the spread plate technique was employed in which the swabbed samples were inoculated into Chocolate agar. Result showed toilet seat bowl coded DER had a Haemophilus influenzae mean count of 5 x 102CFU/ml while codes TYU and AFR had a mean Haemophilus influenzae counts of 6 x 102 and 9 x 102 CFU/ml respectively. A percentage frequency occurrence of Haemophilus influenzae on the toilet bowl showed DER coded toilets had 17% frequency of occurrence, while codes TYU and AFR had 25 and 58% frequency of occurrence respectively. A total of 49 isolates of Haemophilus influenzae were identified macroscopically and biochemically. The presence of Haemophilus influenzae on surface of toilet seat bowl may have resulted from aerosols generated during flushing. Thus, influenza infection (respiratory tract infection) may affect users. Hence, toilet seats, specifically, codes AFR class of toilets should be closed before and after flushing at all times.

Facultative Bacterial Diversity Associated with Silverleaf Whitefly, Bemisia tabaci (Gennadius) on Tomato Crop

The adults and nymphs of Bemisia tabaci were collected on tomato crop from different locations of Karnataka during 2021-2023. Bacterial colonies were isolated from adults and nymphs of B. tabaci using spread-plate technique and identified through 16srRNA sequencing. Nymphs showed high (55%) abundance of bacteria than adults (45%). 63.64% of the bacterial population in the nymphs belong to the phylum Bacillota followed by pseudomonadota (36.36%). In adults, Bacillota found dominant (100%). The class Bacilli was dominant in both nymphs and adults (63.64 and 100% respectively). In the nymphal stage, Bacillales was dominant order (54.55%). Similarly, in adults also Bacillales was found dominant (77.79%). Bacillaceae was abundant in nymphs (45.45%)and in adults same family accounted for 66.67%. The genus Bacillus was dominant in both nymphs (45.45%) and adults (55.55%). The species, B. licheniformis, B. pumilus, B. safensis and Staphylococcus saprophyticus were found common between adults and nymphs. The bacterial diversity varies with the different stages of the B. tabaci on same host.

MICROBIAL LOAD AND ANTIBIOTICS RESISTANCE PATTERNS OF BACTERIAL ISOLATES FROM NIGERIA NAIRA NOTES

In our society today, exchange of goods and services usually involves exchange of currency notes by hand. This can serve as a means of transferring microorganisms and antibiotics resistant bacterial isolates. This study was aimed at assessing the contamination of Naira notes in Ungwan Rimi area of Kaduna State and to determine the antibiotics resistance patterns of the isolated bacteria. A total of 160 samples of naira notes, were collected randomly from staff and students, marketers, hospital and pharmacies, food vendors and transporters at strategic spots in Ungwan Rimi. Bacteria isolation and identification of samples were carried out using spread plate technique on medium and standard biochemical characterization, respectively. Antibiotics susceptibility testing were carried out using agar disc diffusion method. Isolates that were non-susceptible to at least one antimicrobial agent in three or more antimicrobial classes were classified as multidrug resistant (MDR), those that remain susceptible to agent(s) in only one or two classes as extended drug resistant (XDR) while pandrug resistant (PDR) isolates were classified as those isolates that were resistant to all antibiotics used. Highest bacterial load was observed with N100 notes with marketers (5.33 x 105) while the least bacterial load was 1.2 x 104 in N50 notes from hospitals and pharmacies. The following bacteria were isolated Staphylococcus aureus 70 (26.8%), Bacillus spp 60 (23.0%), Clostridium spp 31 (11.9%), Escherichia coli 30 (11.5%), Streptococcus species 25 (9.6%), Klebsiella spp 24 (9.2%), Salmonella 15 (5.8%), Shigella species 4 (1.5%) and Pseudomonas species 2 (0.8%)...

Emerging antibiotic resistance in Plesiomonasshigelloides: insights from surface waters in Southwest Nigeria

Abstract This study aimed to investigate the antibiotic resistance pattern, extended-spectrum β-lactamase (ESBL) production, and biofilm formation potential of Plesiomonas shigelloides in selected surface waters in southwestern Nigeria. Isolates were identified using the spread plate technique on inositol brilliant green bile agar and confirmed molecularly by polymerase chain reaction. Antibiotic susceptibility was determined using the Kirby–Bauer disc diffusion method, ESBL production by the double disc synergistic test, and biofilm formation by the test tube method. A total of 111 P. shigelloides isolates were identified and confirmed. Significant resistance rates were observed against cefuroxime (71%), cefotaxime (92%), and ceftazidime (92%), while high susceptibility was noted for ciprofloxacin (94%), gentamicin (96%), and chloramphenicol (100%). A higher prevalence of multiple drug resistant phenotypes was observed during the dry season, reaching 79% and 60% along sampled rivers. Biofilm-producing phenotypes exhibited robust homogeneous biofilm formation. In this study, P. shigelloides exhibited high resistance to critical antibiotics such as third-generation cephalosporins. However, isolates displayed susceptibility to ciprofloxacin, gentamicin, and chloramphenicol. The presence of ESBL phenotypes and strong biofilm formation emphasizes the potential threat of P. shigelloides as an emerging environmental pathogen, highlighting the importance of monitoring and understanding antibiotic resistance patterns for effective public health management strategies.

Pioneer access of the foam nest bacterial community of Leptodactylidae frogs and its biotechnological potential.

Many anuran amphibians deposit their eggs in foam nests, biostructures that help protect the eggs and tadpoles from predators. Currently, there are no other identification and description studies of the cultivable microbiota role in the nests of the Leptodactylid frogs such as Physalaemus cuvieri, Leptodactylus vastus and Adenomera hylaedactyla. This study aimed to isolate and identify the culturable bacteria from these three anuran species' nests, as well as to prospect enzymes produced by this microbiota. Foam nests samples and environmental samples were diluted and viable cell count was determined. Bacterial morphotypes from foam nest samples were isolated through spread plate technique. Isolates' DNAs were extracted followed by rRNA 16S gene amplification and Sanger sequencing. To evaluate their enzymatic potential, the isolates were cultured in ATGE medium supplemented with starch (0.1% w/v), gelatin (3% w/v) and skimmed milk (1% w/v), to verify amylase and protease activity. A total of 183 bacterial morphotypes were isolated, comprising 33 bacterial genera. Proteobacteria phylum was the most abundant in all the three nests (79%). The genera Pseudomonas and Aeromonas were the most abundant taxon in P. cuvieri and L. vastus. In A. Hylaedactyla, were Enterobacter and Bacillus. Regarding enzymatic activities, 130 isolates displayed protease activity and 45 isolates were positive for amylase activity. Our results provide unprecedented information concerning culturable bacterial microbiota of the foam nests of the Leptodactylid frogs, as well as their potential for biomolecules of biotechnological interest.

Investigating the presence of multidrug-resistant Escherichia coliin raw mutton from open marketplaces

The objective of this research was to identify antibiotic-resistant strains of Escherichia coliand examine the occurrence of E. coli in mutton samples sourced from multiple locations within two districts, given the serious public health risks associated with its presence in food. Six mutton samples were procured from open markets in Kushtia, while another six were sourced from markets in Jhenaidah.Serial dilutions were made by processing mutton after samples were gathered from every region. The samples were plated on nutrient agar and cultured for bacterial growth using the spread plate technique. Following incubation, bacterial contamination was evident in every sample, ranging from 1.2×109 CFU/mL to 4.7×109 CFU/mL. After conducting selective agar tests (MacConkey agar and Eosin-methylene blue) and biochemical tests (Methyl Red, Catalase, Citrate,Oxidase, Indole, and Voges-Proskauer test) to verify the presence of E. coli, it was discovered that 66.67% of the samples of mutton were positive for the E. coli. Then, the E. colistrains were subjected to additional investigation, which showed resistance to three (Amoxicillin,30 μg;Penicillin,10 μg;and Co-trimoxazole, 25 μg)of the eight tested antibiotics and another five (Ciprofloxacin, 5 μg;Azithromycin, 30μg; Streptomycin, 10 μg;Levofloxacin, 5μg;and Erythromycin, 15μg)antibiotics were sensitive. The study underscores the possibility of antibiotic-resistant and multidrug-resistantE. coli in mutton samples, underscoring the need forappropriate handling and cooking techniques to prevent foodborne illnesses from mutton contamination.

Engineered nanovesicles from activated neutrophils with enriched bactericidal proteins have molecular debridement ability and promote infectious wound healing.

Bacterial infections pose a considerable threat to skin wounds, particularly in the case of challenging-to-treat diabetic wounds. Systemic antibiotics often struggle to penetrate deep wound tissues and topically applied antibiotics may lead to sensitization, necessitating the development of novel approaches for effectively treating germs in deep wound tissues. Neutrophils, the predominant immune cells in the bloodstream, rapidly release an abundance of molecules via degranulation upon activation, which possess the ability to directly eliminate pathogens. This study was designed to develop novel neutrophil cell engineered nanovesicles (NVs) with high production and explore their bactericidal properties and application in promoting infectious wound healing. Neutrophils were isolated from peripheral blood and activated in vitro via phorbol myristate acetate (PMA) stimulation. Engineered NVs were prepared by sequentially extruding activated neutrophils followed by ultracentrifugation and were compared with neutrophil-derived exosomes in terms of morphology, size distribution and protein contents. The bactericidal effect of NVs in vitro was evaluated using the spread plate technique, LIVE/DEAD backlight bacteria assay and observation of bacterial morphology. The therapeutic effects of NVs in vivo were evaluated using wound contraction area measurements, histopathological examinations, assessments of inflammatory factors and immunochemical staining. Activated neutrophils stimulated with PMA in vitro promptly release a substantial amount of bactericidal proteins. NVs are similar to exosomes in terms of morphology and particle size, but they exhibit a significantly higher enrichment of bactericidal proteins. In vitro, NVs demonstrated a significant bactericidal effect, presumably mediated by the enrichment of bactericidal proteins such as lysozyme. These NVs significantly accelerated wound healing, leading to a marked reduction in bacterial load, downregulation of inflammatory factors and enhanced collagen deposition in a full-thickness infectious skin defect model. We developed engineered NVs derived from activated neutrophils to serve as a novel debridement method targeting bacteria in deep tissues, ultimately promoting infectious wound healing.

Assessment of Water Quality Parameters in Lake Hayq, Northeastern Ethiopia.

Lake Hayq is one of the highland lakes of Ethiopia that furnishes very important ecosystem services, fishing, tourism, transportation, drinking water, livestock watering, and irrigation. However, the lake ecosystem is being degraded by pollution, siltation, and excessive growth of macrophytes, buffer zone degradation, overfishing, and climate variability. Therefore, this study was conducted to assess the physicochemical, heavy metals, and biological water quality parameters of Lake Hayq. Physiochemical (pH, water temperature, conductivity, TDS, total alkalinity, dissolved oxygen, Ca2+, Mg2+, Na+, K+, NH4+, NH3, NO2 -, NO3 -, CO3 -, HCO3 -, SO4 2-, PO4 3-, SiO2, and total phosphorus), heavy metals (Pb, Fe, Zn, Cr, Cu2+, Mn2+, and Ni), and biological (BOD5 and total coliforms) water quality parameters were analyzed both in situ and ex situ. The physicochemical parameters were measured using portable water quality measuring multimeters, the heavy metal analysis was done using the Atomic Absorption Spectrometer, the BOD5 was measured using a BOD5 meter, and the total coliform analysis was done using the spread plate technique. The collected data were analyzed using multivariate, two-way ANOVA to see the mean difference among sampling sites and seasons through the application of SPSS 16. Most of the water quality parameters of Lake Hayq have met the WHO standards for recreation, aquatic life, and drinking water quality. However, some parameters, such as Pb, BOD5, and total coliforms, were above WHO water quality permissible limits. Therefore, ecohydrological (nature-based) waste treatment methods such as macrophyte restoration in buffer zones and ecofriendly farming activities should be practiced to minimize the contamination of the lake.

Detection of genes conferring resistance on multi antibiotic resistance bacteria isolated from ready to eat foods sold in the Nigerian defence academy, Kaduna, Nigeria

Food has always been the means by which disease-causing organisms are transmitted to man. This study sought to isolate multi-antibiotic resistant bacteria from ready to eat food (RTE) sold within Nigerian Defence Academy. Eight (8) food samples were collected from five (5) vendors and spread plate technique was adopted for bacteria isolation from the food samples. Twenty-five (25) bacteria isolates were obtained from the food samples and subjected to antibiotic sensitivity assay using Kirby Bauer disc diffusion method. Eight (8) of the isolates exhibited various degrees of resistance to the tested antibiotics. All the isolated bacteria in this study were susceptible to the effect of Quinolones antibiotics and were resistant to cefuroxime, cefotaxime and Ampiclox. Six (6) of the isolates that showed multi-antibiotic resistance were characterized by 16SrRNA gene sequencing as Bacillus cereus strains (0083 and HYM76), Staphylococcus aureus strain MRSA252, Lactobacillus murinus strain AMB_10 and Listeria Spp. Polymerase chain reaction (PCR) and agarose gel electrophoresis detection of four (4) antibiotics resistance genes – Aminoglycoside adenylyltransferase (AADA1), Acridine (ACRA), Chloramphenicol Resistance (CMLA) and Erythromycin (ERM(C)) – produced the following results: AADA1 genes were amplified in Staphylococcus aureus and Bacillus cereus; ACRA gene was detected in all the selected isolates; CMLA gene was detected in Staphylococcus aureus, Lactobacillus murinus and Bacillus cereus while ERM(C) gene was present in Staphylococcus aureus.

Antibacterial and Phytochemical Properties of Clove Extracts on Vegetable Spoilage Bacteria

The present study was carried out to analyze the antibacterial and phytochemical properties of clove extracts on vegetable spoilage bacteria. The study seeks to determine its potential use as bio-preservative. The bacteria used for this study were isolated from infected leaves of bitter leaf, pumpkin and cocoyam using spread plate technique. Phytochemical analysis was carried out with aqueous and methanol extracts. Bacterial isolates from the leaves included Bacillus spp., Micrococcus spp., Staphylococcus spp. and Actinomyces spp. The pumpkin leaf had the highest average number of bacterial colonies of 2.5 x 102 while cocoyam leaf had the least with 7.0 x 101.Actinomycetes sp2 had the highest zone of inhibition of 22.0 mm while Staphylococcus sp2 had the least zone of inhibition of 13.00 mm all at 500mg/ml. For aqueous extracts, Bacillus sp.3, Staphylococcus sp.1 had the highest zone of inhibition of 16.00 mm respectively while the least zones were observed in Staphylococcus sp.2 and Bacillus sp.3 at concentration of 250 mg/ml and 125 mg/ml respectively. Bacillus sp.1, Bacillus sp.2, Micrococcus sp. and Actinomyces sp.1 has Minimum Inhibition Concentration (MIC) of 125 mg/ml while Staphylococcus sp.1 and Staphylococcus sp.2 has 250mg/ml respectively for methanol extract. For aqueous extract, Bacillus sp.2, Micrococcus sp. and Actinomyces sp.1 has MIC of 250mg/ml, respectively and Staphylococcus sp.1 and Staphylococcus sp.2 has MIC of 500 mg/ml. The Minimum Bactericidal Concentration (MBC) for the methanol extracts was 125 mg/ml for Actinomyces sp.1 while Bacillus sp.2, Bacillus sp.3, Micrococcus sp. and Actinomyces sp.2 were 250 mg/ml respectively while Bacillus sp1, Bacillus sp2, Micrococcus sp., Staphylococcus sp.2 and Actinomyces sp.1 all has MBC of 500mg/ml, respectively on the aqueous extracts. The phytochemical analysis of the aqueous and methanol extracts of clove shows that saponins, tannins, amino acids, proteins, reducing sugar, glycosides, alkaloids, anthraquinone and phenols are present though in varying amounts. This study therefore recommends clove extract as an alternative source for bio-preservation in food and allied products.

Development of state of art test setup to measure thermal conductivity of soils infused with treated and un‐treated natural microorganisms

AbstractSoil is a natural heterogeneous material and from its formation process, heat transfer capacity (thermal conductivity) of soil is playing vital role in many engineering applications. The aim of this research study is to enhance thermal conductivity using natural and treated bacteria from soil samples procured from four different regions namely Dholera, Navsari, Sabarmati River, and Madhavpur of Gujarat, India. To fulfill this objective, thermal conductivity test set‐up was indigenously developed based on guarded hot plate method and is calibrated up to 150°C temperature. The colonies of microorganisms available in soil were studied by serial dilution and spread plate technique. Further, influence of microorganisms on soil structure aggregation pre and post treatment was analyzed by microscope. Four types of microorganisms were introduced in the soil and the thermal conductivity of sample is measured for curing period of 7, 14, 21, and 28 days. The results indicate increment in k value for thermal conductivity in clayey soil up to 26.67% and decrement in sandy soil is up to 45.45%, while most optimum results were observed for 7 days curing period. Present research demonstrates use of microbes available in various soils to enhance heat transfer mechanism through proper identification and treatment.