Bacterial contaminants of new disposable ready-to-use plastic cups sold within Gombe Metropolis, Gombe State, Nigeria

Background: Disposable cups are usually used for drinking without any form of pre-cleaning, this has the potential to expose individuals to pathogenic microorganisms, and unfortunately this issue has not been investigated in Gombe metropolis, hence, this study aimed to investigate the bacteriological aspect of the problem and to reduce the existing knowledge gap regarding this problem. Methods: Thirty samples were collected using simple random sampling from two different markets, then swab sticks pre-moistened with peptone water were used to swab the inner portions of the cups, put in sterile distilled water, serially diluted, inoculated on nutrient agar, and incubated. Identification of the isolates were done using their physical and biochemical characteristics, antibiotic susceptibility tests were done using disc diffusion method and interpreted using Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: The total mesophilic bacterial counts ranged from 3.0×105 to 9.9×105 CFU/ml. These isolates were identified and tested for their sensitivity to some antibiotics which revealed that Escherichia coli  (E.coli ) were sensitive to augmentin, ampicillin, and ciprofloxacin, but intermediately resistant to chloramphenicol, Staphylococcus aureus (S. aureus)  were sensitive to ciprofloxacin and augmentin, intermediately resistant to chloramphenicol, and resistant to ampicillin. Bacillus spp were sensitive to augmentin, ciprofloxacin, chloramphenicol and ampicillin, while Pseudomonas aeruginosa (P.aeruginosa) were sensitive to ciprofloxacin, augmentin, and chloramphenicol, but intermediately resistant to ampicillin. Conclusion: These new disposable ready-to-use cups harbored some potentially pathogenic bacteria which were resistant to some antibiotics. It is therefore recommended that pre-use hygiene practices should be done on these cups prior to use to avert the health effects of consuming these bacteria

Optimisation and dose responses of bioluminescent bacterial biosensors induced with target hydrocarbons

Routine analytical methods are constrained in the speed of application, sample throughput and inability to determine the right bioavailable loading of pollutants. Microbial biosensor technology resolved these constraints by offering the most rapid, sensitive, reliable and cost-effective technology, especially in a bioavailable context. This study describes the growth characterisation and optimisation of three different lux-marked biosensors and their induction bioassay, thus testing their responses to doses of target hydrocarbons (naphthalene, toluene, Isopropylbenzene) and solution of mixed hydrocarbons. These biosensors, Pseudomonas fluorescence HK44, Escherichia coli HMS174 and Pseudomonas putidaTVA8 harbours luxCDABE reporter genes coupled to induction by hydrocarbons. Biosensors harvested at optimal exponential phase and induced with hydrocarbon using the optimised assay conditions are highly sensitive and responsive to their inducers in a proportionate dose-dependent status. The established dose responses of these catabolic biosensors signify the prospect of extrapolation for estimating the genuine contamination loading of pollutants for environmental relevance. However, several factors may contribute to the quenching effect at high concentration of inducers. Robust responsiveness to mixed hydrocarbon solution has been also realised accentuating its feasibility in analysing of real environmental samples containing heterogenous pollutants. This study emphasises the suitability of bioluminescent bacterial biosensors for pollutants analysis and notably the detection of soluble bioavailable fractions of diverse hydrocarbons, hence, serves as a reliable bioindicator of hydrocarbon pollution in an environment. Even so, the real value of biosensors is for a suite of ecologically justified biosensors to be applied in complementary combinations with other focused analytical or chemical methods for broad and resourceful inference

Response surface methodology optimisation and kinetics of diesel degradation by a cold-adapted Antarctic bacterium, Arthrobacter sp. strain AQ5-05

Petroleum hydrocarbons, notably diesel oil, are the main energy source for running amenities in the Antarctic region and are the major cause of pollution in this area. Diesel oil spills are one of the major challenges facing management of the Antarctic environment. Bioremediation using bacteria can be an effective and eco-friendly approach for their remediation. However, since the introduction of non-native organisms, including microorganisms, into the Antarctic or between the distinct biogeographical regions within the continent is not permitted under the Antarctic Treaty, it is crucial to discover native oil-degrading, psychrotolerant microorganisms that can be used in diesel bioremediation. The primary aim of the current study is to optimize the conditions for growth and diesel degradation activity of an Antarctic local bacterium, Arthrobacter sp. strain AQ5-05, using the Plackett-Burman approach and response surface method (RSM) via a central composite design (CCD) approach. Based on this approach, temperature, pH, and salinity were calculated to be optimum at 16.30 °C, pH 7.67 and 1.12% (w/v), respectively. A second order polynomial regression model very accurately represented the experimental figures’ interpretation. These optimized environmental conditions increased diesel degradation from 34.5% (at 10 °C, pH 7.00 and 1.00% (w/v) salinity) to 56.4%. Further investigation of the kinetics of diesel reduction by strain AQ5-05 revealed that the Teissier model had the lowest RMSE and AICC values. The calculated values for the Teissier constants of maximal growth rate, half-saturation rate constant for the maximal growth, and half inhibition constants (μmax, Ks, and Ki), were 0.999 h−1, 1.971% (v/v) and 1.764% (v/v), respectively. The data obtained therefore confirmed the potential application of this cold-tolerant strain in the bioremediation of diesel-contaminated Antarctic soils at low temperature

Kinetic studies of marine psychrotolerant microorganisms capable of degrading diesel inthe presence of heavy metals

The presence of heavy metals in Antarctica is an emerging issue as human influence becomes more discernible over the years.The study of pollution in Antarctica can help people to understand the real influence of human activities on the environmental pollution from polar regions. Bioremediation of petroleum hydrocarbons in the polar environment where toxic metals co-existed involves selecting strictly auto chthonous Antarctic strains with dual catabolic competence and tolerance to toxic metals. In this study, diesel degradation was observed in the presence of 1 ppm of eight selected heavy metals; Ag, Al, Cd, Co, Cr, Hg, Ni and Zn. Bacterial growth was inhibited in increasing order of Zn>Cr>Cd>Al>Ni>Hg>Co>Ag. Bacterial growth was the highest in Zn at OD 6000.556 (P>0.05) and lowest in Ag at OD 6000.151 (PNi>Cd>Ag>Zn>Al>Cr>Hg, which was analysed using gravimetry analysis. Degradation was the highest in Hg at 52.23%(P>0.05) and lowest in Co at 22.76% (P<0.05). This work serves as a pilot study in gathering data to analyse and gather moredata for inhibition concentration of heavy metals for the Antarctic marine bacteria

Runs test for the residuals of the Morgan-Mercer-Flodin MMF model used for modelling the total number of Covid-19 cases for Brazil

Numerous papers fail to conduct statistical diagnostics of the nonlinear model that was used, and the data may be nonrandom, which is a need for all parametric statistical evaluation procedures that rely on random data. Whenever the diagnostic tests find that the residuals reflect a pattern, there are a range of treatments available, such as nonparametric analysis or transferring to a different model, which should resolve the issue. Organisms’ growth including viral infection cases over time usually exhibit a sigmoidal growth profile that exhibits lag time, acceleration to a maximal value and a final phase where the rate decreases and eventually reaches zero or an asymptote (A) is observed. For the analysis of the COVID-19 pandemic, the total infection case of SARS-CoV-2 in Brazil as of 15th of July 2020 to the 20thof December 2020 was modelled using several primary growth models with the Morgan-Mercer-Flodin (MMF) model found to be the best. We were the first to note on the high suitability of the MMF model to fit total death and infection cases for COVID-19. The least-squares technique used in normal nonlinear regression including in the MMF model must be subjected to the notion that the residual values must be random. In order to satisfy this requirement, we conduct the Wald–Wolfowitz runs test statistical diagnosis tests. The maximum number of runs counting was 5, and the predicted number of runs under the premise of randomness was 25.96. The z-value indicates how many normal errors the number of runs discovered exceeds the anticipated number of runs, and the p-value indicates how severe this z-value is. The significance is the same as with the other data on p-values. The null hypothesis that the residuals are really random can be rejected if the p-value is less than 0.05. Because the p-value was smaller than 0.05, the null hypothesis was dismissed, implying that there is strong evidence of non-randomness of the residues and further remedy is needed

Enumeration of total and Feacal coliform bacteria of some borehole water in Gombe, Gombe State, Nigeria

Inadequate provision of potable drinking water in relation to teaming population is forcing most of the urban communities to drink untreated water obtained from traditional boreholes. Hence, the need to assess the portability of drinking water. In this research, boreholes water samples collected within Gombe city were investigated bacteriologically using multiple tube fermentation and pour plate methods to examine feacal coliform and coliform bacterial counts respectively; bacterial isolation was conducted using standard culture methods.&nbsp; Identification of the bacterial Isolates were carried out by macroscopic, microscopic and biochemical examinations. Total coliform bacteria ranges from &lt;3 to 11 MPN/100 ml and 1 to 3 MPN/100ml for faecal coliform. The borehole water samples from studied areas had high counts of faecal coliforms (Escherichia coli), and other pathogens like Entrobacter and Salmonella. The findings showed that all the borehole water analysed were not suitable for human consumption and may pose a serious threat to the health of consumers and therefore, there is need for treatment of these borehole waters by the borehole proprietors and also by simple treatment methods such as boiling, filtration before drinking and agitation by the consumers.&nbsp;&nbsp;&nbsp; Keywords: Borehole water, Quality, Isolation, Identification, Coliform bacteri

Effects of heavy metals on diesel metabolism of psychrotolerant strains of Arthrobacter sp. from Antarctica

Aim: This present study aimed at examining the ability of cold-adapted Antarctic bacteria to tolerate and degrade diesel in the presence of different types of heavy metal co-pollutants. Methodology: Arthrobacter sp. strains AQ5-05 and AQ5-06, originally isolated from Antarctic soils, were grown on Bushnell-Haas medium containing 1 ppm of heavy metal ions (As, Ag, Cd, Co, Cu, Cr, Hg, Ni, and Pb) supplemented with 3% (v/v) diesel. Diesel degradation was determined gravimetrically, while bacterial growth was evaluated by measuring the optical density of media (OD600 nm). Results: In the absence of heavy metal ions, strain AQ5-06 achieved 37.5% diesel mineralisation, while strain AQ5-05 achieved 34.5%. The diesel degrading abilities of both strains were significantly inhibited by exposure to < 1 ppm of Ag or Hg. In contrast, no change in degradation ability was observed using other tested heavy metals. The IC50 of Ag and Hg on diesel degradation by the two strains were (0.2 and 0.4 ppm) and (0.3 and 0.2 ppm), respectively. Interpretation: Arthrobacter sp. Strains AQ5-05 and AQ5-06 may contain genes for alkane degradation and heavy metal resistance for remediating diesel-polluted soil in Antarctic and other cold regions

Biodegradation of diesel oil by cold-adapted bacterial strains of Arthrobacter spp. from Antarctica

Bioremediation has been proposed as a means of dealing with oil spills on the continent. However, the introduction of non-native organisms, including microbes, even for this purpose would appear to breach the terms of the Environmental Protocol to the Antarctic Treaty. This study therefore aimed to optimize the growth conditions and diesel degradation activity of the Antarctic native bacteria Arthrobacter spp. strains AQ5-05 and AQ5-06 through the application of a one-factor-at-a-time (OFAT) approach. Both strains were psychrotolerant, with the optimum temperature supporting diesel degradation being 10–15°C. Both strains were also screened for biosurfactant production and biofilm formation. Their diesel degradation potential was assessed using Bushnell–Haas medium supplemented with 0.5% (v/v) diesel as the sole carbon source and determined using both gravimetric and gas chromatography and mass spectrophotometry analysis. Strain AQ5-06 achieved 37.5% diesel degradation, while strain AQ5-05 achieved 34.5% diesel degradation. Both strains produced biosurfactants and showed high biofilm adherence. Strains AQ5-05 and AQ5-06 showed high cellular hydrophobicity rates of 73.0% and 81.5%, respectively, in hexadecane, with somewhat lower values of 60.5% and 70.5%, respectively, in tetrahexadecane. Optimized conditions identified via OFAT increased diesel degradation to 41.0% and 47.5% for strains AQ5-05 and AQ5-06, respectively. Both strains also demonstrated the ability to degrade diesel in the presence of heavy metal co-pollutants. This study therefore confirms the potential use of these cold-tolerant bacterial strains in the biodegradation of diesel-polluted Antarctic soils at low environmental temperatures