Molecular characterization of xanthan gum producing Xanthomonas Campestris isolated from dark rot spotted leaves in Keffi, Nasarawa State, Nigeria

Background: Despite the wide application of Xanthan gum, its commercial production remains a global challenge. In recent years, considerable research has been carried out using agro-industrial wastes, which are renewable and abundantly available to produce value-added products. The present study was set out for molecular identification of Xanthomonas campestris from leaves of four different plants with indications of dark rot spots and evaluation of their xanthan gum production capacity. Methods: Twenty-five (25) samples of leaves from four different plants with indications of dark rot spots were collected from the study area and isolated for Xanthomonas campestris following standard microbiological methods. Cultural, morphological and biochemical tests were conducted to confirm the organism. Results: The results revealed that of the total 100 samples taken, 6 leaves (24%) were infected with Xanthomonas species in mint, 3(12%) were infected in mango, 1(4%) were infected in rice and 2(8%) were infected in pepper. Further molecular identification of the isolates was carried out to reveal Xanthomonas campestris pv. vesicatoria strain 85-10 and Xanthomonas perforans strain 91-118. These were further used for the production of xanthan gum using sugar cane molasses substrates extracted from sugar cane, which was used as fermentation medium for the production. Isolates from plants varying ability in Xanthan gum production, with the mint plant having the highest Xanthan gum production (0.10 ± 0.02 to 0.9 ± 0.00 g/l). Conclusion: The present study confirmed the high xanthan gum production capacity of Xanthomonas campestris from dark rot spots containing mint leaves and should be considered during local and industrial production of the xanthan gum

Antimicrobial Susceptibility Pattern of Enteric Bacteria from Fresh cow milk and handlers in Zaria Metropolis, Kaduna State Nigeria

A bacteriological examination of raw cow milk for the isolation of enteric based bacteria was conducted on milking cows and their handlers from selected farms in four Local Governments in Zaria, Kaduna State. The aim of the study was to check the quality of the raw cow’s milk and also verify the rate of contaminations of the raw cow’s milk from external sources which are regarded as environmental pathogens during and after milking processes. A total of 105 samples; 42 raw milks from lactating cows, 42 swabs from cow teat, 16 swabs from herd handlers and 5 samples from water used in the cleaning process were obtained. The raw milk samples were screened using a Methylene dye reagent to check its microbial load before analysis began, the total bacteria count (TBC) and total coliform count (TCC) were analyzed using the standard cultural methods. The isolates were identified using the standard biochemical procedure and Microgen TM System (GN-ID A+B Kit). Results revealed that one hundred and two (102) bacteria consisting of Seventy-six (76) Polymicrobial and twenty-six (26) single cultures were recovered as positive culture while three (3) had no growth. The mean TBC and TCC of raw milk observed in this study were 2.56 ± 0.40 x104cfu/ml and 1.06 ± 0.16 x104cfu/ml respectively. Acinetobacter iwoffi and other members of Enterobacteriaceae isolates were resistant to tetracycline (68.75%), erythromycin (71.74%) and metronidazole (100%), while high susceptibility was observed to gentamicin (94.34%) and chloramphenicol (80.85%). High bacterial contaminations including Multidrug-resistant bacteria were observed in this study, contaminations were majorly from improper pre and post dipping processes and the use of non-portable water

Antibiotic susceptibility pattern of Escherichia coli isolated from food, cooking utensils and palms of food handlers in some restaurants in Zaria, Nigeria

Foodborne disease is a major public health problem causing considerable morbidity and mortality annually. In the present study, the antibiotic susceptibility patterns of Escherichia coli isolated from food, cooking utensils and palms of food handlers in some restaurants in Zaria, Nigeria were evaluated. A total of 250 samples (220 food samples, 7 hand samples of food handlers, 10 plate samples within restaurants and 13 spoon samples) were collected from five locations in Zaria, Nigeria and analysed for microbial contaminations using standard microbiological techniques. The antibiotic susceptibility pattern of the isolates was determined using Kirby-Bauer modified disc agar diffusion technique. Results revealed that out of 158 acclaimed Enterobacteriaceae isolates evaluated, 19 % (30) were confirmed to be E. coli, while 81 % were Klebsiella. spp, Citrobacter fruendii, Enterobacter spp, Shigella spp, Salmonella spp, Serratia spp, and Cronobacter sakazaki. The majority of the isolates were resistant to amoxiclav (26.08%), ampicillin (26.08%), tetracycline (26.08%) and metronidazole (13.04%). A 33.3% of the isolates were multidrug-resistant. The E. coli isolates were mostly multiple antibiotic resistance with 43.3% having multiple antibiotic resistance index (MARI) ≥ 0.2. In conclusion, E. coli evolved resistance to ampicillin, Amoxicillin Clavulanic acid, and Tetracycline and other tested antimicrobial drugs which would make the treatment of Escherichia coli infections difficult

In vitro inhibition of multi-drug resistant Pseudomonas efflux pump by Xylopia aethiopica (Dunal) A. Rich

Global health is under constant threat due to antimicrobial drug resistance. Bacterial Infections caused by Pseudomonas aeruginosa are of importance because of their antibiotics resistance. This study aimed at evaluating the effects of extracts of Xylopia aethiopica (XA) on multidrug-resistant (MDR) Pseudomonas isolates. Fresh samples of XA leaf, stem bark and roots were collected from the botanical garden, University of Ibadan, Nigeria. Dried and pulverized samples were extracted with methanol and partitioned into n-hexane, dichloromethane and ethyl acetate. Phytochemical screening of the extracts was performed by standard methods. Antimicrobial activity and synergistic interaction were determined using microdilution and checkerboard broth dilution methods, respectively. The results revealed that crude methanol extracts of XA leaf, stem bark and root significantly (p<0.05) inhibited the growth of all tested MDR Pseudomonas isolates at 10 mg/mL. At 1 mg/mL, the ethyl acetate fraction of the leaf, and dichloromethane fraction of the roots produced clear zones of inhibition of 12 – 20 mm, and minimum inhibitory concentrations (MICs) of 1 µg/mL and 0.5 mg/mL, respectively. The modulation factor (MF) of ciprofloxacin, dichloromethane fraction of XA roots and ethyl acetate fraction of XA leaf were 4, 8, and 4 on MDR isolates E01006, OAU058 and P. aeruginosa ATCC 27853, respectively. In all tested isolates, but not E01006 and E01024, the fractional MICs of ciprofloxacin/ethylacetate fraction of XA leaf extract combination was not significantly different (p>0.05) compared with ciprofloxacin/verapamil combination. In conclusion, the root and leaf fractions Xylopia aethiopica that demonstrated antimicrobial activity against MDR P. aeruginosa and synergised with ciprofloxacin have the potential to rejuvenate the antimicrobial activity of ciprofloxacin in MDR P. aeruginosa.

Extraction and characterization of type 1 collagen from the skin and scales of Heterotis niloticus and Lates niloticus

The study is aimed to extract and characterize collagens from the skin and scale of two selected Nigerian freshwater fish species (Heterotis niloticus and Lates niloticus) using either pepsin (PSC) or acid-soluble (ASC) extraction. The collagen was extracted using 0.5M acetic acid and pepsin. The collagen yield was determined and characterized by SDS PAGE, and FTIR. Collagen extraction yields varied with the extraction process; the yield was significantly higher in the skin (5.08±0.34–33.97±1.78 %) than in the scale (1.76–8.05 %). The absorption peaks of the extracted collagen using acetic acid and pepsin show that only ASC of skin (3344.27 cm-1) and scale (3495.85 cm-1) of H. niloticus shows the peaks characteristic of Amide A, while Amide B peaks of collagen extracted from the skin and scale of H. niloticus and L. niloticus were found at 2974.46 cm-1 and 2925.7 cm-1 , representing an asymmetrical stretch of CH2. Similarly, ASC on the skin (1558.36 cm-1) and scale (1576.46 cm-1) of H. niloticus shows the absorption peak characteristics of amide II. ASC on the skin of H. niloticus (1671.05 cm-1), PSC on scale of H. niloticus (1658.55 cm-1), and on scale of H. niloticus (1678.65 cm1) shows absorption peaks in range characteristic of amide 1. There were no differences in the skin and scale collagen profiles among the two fish species when characterized by SDS-PAGE. Our data revealed that the skin and scale of Lates niloticus and Heterotis niloticus could be a good alternative source of high-quality collagen for industries.

Phytochemical and safety evaluations of Diospyros mespiliformis, and in silico evaluations of drug-likeness, pharmacokinetics and acute toxicity of its bioactive compound (Diospyrin)

Diospyros mespiliformis is among the popular multipurpose tropical fruit trees, commonly used as herbal medicines. However, due to the lack of adequate scientific data on the safety of this plant, the present study was conducted to determine the phytochemical compositions and acute toxicity profile of the crude methanol extract of D. mespiliformis. In addition, diospyrin, a bioactive compound from the plant was evaluated for in silico drug-likeness, pharmacokinetics (PKs) and acute toxicity. The phytochemical contents of the plant were quantified using standardized protocols while the 50% lethal dose (LD50) was evaluated using Lorke’s methods. Results revealed that flavonoids (265.46±0.32 mg/g) are the most abundant phytochemical in methanol leaf extract of D. mespiliformis, followed by alkaloids (224.56±0.19 mg/g) and phenols (191.82±0.04 mg/g) while saponins (7.90±0.32 mg/g) was the least abundant phytochemical. The plant extract has LD50 of > 5000 mg/kg in rats. No death was recorded throughout the study period. Similarly, no behavioural changes were observed in animals dosed with the crude extract at 10 -2900 mg/kg BW. Animals administered 5000 mg/kg BW were hyperactive, restless, and displayed profused breathing which lasted only for 30 minutes after administrations. Diospyrin a bioactive compound from D. mespiliformis demonstrated good druglike candidates and exhibited a high safety profile as revealed by in silico study. In conclusion, the crude methanol extract of D. mespiliformis and its bioactive compound is well-tolerated and non-toxic to rats, and thus could be considered a safe medicinal plant for acute oral remedies