Heterotrophic Bacterial Counts Research Articles

Bacterial Removal Efficiency of Crude Oil Polluted Water Using Corn Husk and Charcoal as Filter Material

Clean drinking water has become a distinguishing factor between developed countries and developing or underdeveloped countries so much so that it is fast becoming the most sought-after initiatives in the public health sector globally. Many people in underdeveloped nations still lack access to safe drinking water, they rely on surrounding rivers and streams for their water supply. Polluted water is not safe for drinking and use in homes for domestic activities as they may pose health risks. It is therefore important to consider effective ways to purify water for domestic use in communities that do not have access to treated water. Microorganisms are key contaminants in unsafe water sources and be of natural or human origin. The frequency of bacterial isolate occurrence showed that the most prevalent were Staphylococcus species (12.0 %), Aeromonas species (10 %), Klebsiella species (9.0 %), Clostridium species and Enterobacter species (8.0 %), while the lowest were Corynebacterium and Bacillus species (4 %). The bacteriological quality of the polluted water before and after filtration was analysed to evaluate the efficacy of charcoal and corn husk filters in removing pathogenic isolates. The total heterotrophic bacterial counts (THB) of the contaminated water reduced by 87.0 % and 88.7 %, hydrocarbon utilizing bacterial counts (HUB) reduced by 87.3 % and 95.4 %, faecal coliforms reduced by 94.5 % and 95.8 %, Salmonella shigella counts reduced by 69.2 % and 76.0 % for corn husk filter and charcoal filter respectively after filtration with the organic materials. Charcoal filter showed more promise in reducing bacterial isolates than corn husk.

Influence of Varied Carbon Sources and Carbon-Nitrogen Ratio on Microbial Community in a Biofloc-Based Culture System and Their Effects on Growth Performance, Proximate Composition, Hematology and Oxidative Stress in Nile Tilapia

This study investigates the influence of varied carbon sources and carbon-nitrogen ratio on microbial community in a biofloc-based culture system and their effects on growth performance, proximate composition, hematology, and oxidative stress in Nile tilapia. The experiment involved three different carbon-nitrogen ratios (10:1, 15:1, 20:1) and two carbohydrate sources (molasses: ML-10, ML-15, ML-20, starch: S-10, S-15, and S-20) with three replicates each. A diet containing 25% crude protein was fed to fish in 18 experimental units for 120 days. Carbohydrate supplementation significantly increased the total heterotrophic bacterial (THB) count from C/N10 to C/N20 while decreasing pH, total ammonia nitrogen, and nitrate nitrogen contents. In addition, growth was considerably greater in the ML-10 and ML-15 groups compared to the C/N20 group. Increasing the C/N ratio increased body protein and ash, decreased lipid contents, and increased the activities of lysozyme, SOD, CAT, and GPx. Finally, the C/N10 and C/N15 groups showed significantly lower GLU and COR concentrations in biofloc compared to the C/N20 group. Furthermore, increasing the C/N ratio up to 15 resulted in improved outcomes in terms of Hb, WBCs, RBCs, and Ht content. Overall, the utilization of the C/N15 group resulted in suitable growth, proximate composition, and immunity in Nile tilapia.

Techno-economic assessment and innovative production of nutrient-rich jam, jelly, and pickle from Sonneratia apetala fruit.

Sonneratia apetala, a nutrient-rich mangrove fruit, presents an opportunity for innovative food product development, offering potential health benefits and economic value through the creation of jam, jelly, and pickle. This innovative invention reveals the nutritional content including vitamins and minerals of Sonneratia apetala jam, jelly, and pickles from Nijhum Dwip in Hatiya Upazila, Noakhali District. These products contain Na, Mg, K, Ca, Mn, Fe, Cu, and Zn, which are essential for human nutrition. The texture and sensory qualities of the products depend on their Total Soluble Solids (TSS), acidity, moisture, pH, and total sugar content, with each parameter receiving an average score of 7 to 8 out of 9 (hedonic scale). Trace amounts of Cd, Cr, Pb, and Hg were found to be significantly below the safe consumption limits. F-, Cl-, SO42-, soluble and total PO43- concentrations were also below safety thresholds. The moisture, ash, protein, fat, fiber, pectin, sugar, carbohydrate, and caloric values highlight the dietary benefits and energy content of these products. The products exhibited higher levels of vitamin C and minerals compared to other citrus fruits. All tested parameters met safe consumption standards, ensuring product safety. These products underwent testing for Heterotrophic Bacterial Count to guarantee their safety. A one-year shelf life is ensured by conducting quarterly storage data checks and organoleptic tests by a 10-member jury panel. The one-way ANOVA test for sensory analysis and shelf life detection indicates statistically significant results. These products help mitigate nutrient deficiencies and promote health by regulating the diet. Applying this technology in grassroots jam, jelly, and pickle production could potentially boost the local economy by approximately $10,000 annually through the creation of small industries among the coastal population.

Assessment of Microbial Contamination and Bacterial Characterization in Ready-to-Eat Fruits from Port Harcourt Markets, Nigeria

Food safety is critical in preventing foodborne illnesses, particularly in regions where regulatory oversight may be inconsistent. This study aimed to assess the microbial contamination and characterize bacteria found in whole and sliced ready-to-eat (RTE) fruits sold in Port Harcourt, Nigeria. The study area of this research was in Port Harcourt, the capital and largest city in Rivers State, Nigeria. The study employed a simple random sampling technique, and the methodology involved collecting 30 samples of apples, cucumbers, oranges, pawpaws, and watermelons from six markets: Fruit Garden Market, Mile 1 Market, Mile 3 Market, Oil Mill Market, Rumuokoro Market, and Town Market. Samples were analyzed using standard microbiological techniques, including total heterotrophic bacterial count (THBC) and total coliform count (TCC). Serial dilutions and culturing were performed, and the isolates were identified through morphological and biochemical tests. Results indicated that coliforms such as Escherichia coli, Klebsiella spp and Enterobacter spp were isolated, and the THBC varied significantly among the markets, with the highest contamination observed in Mile 3 Market (9.50 × 10⁴ CFU/ml) and the lowest in Town Market (7.27 × 10⁴ CFU/ml). TCC results showed the highest coliform contamination in Rumuokoro Market (5.16 × 10³ CFU/ml), likely influenced by proximity to unsanitary water sources. Watermelon had the highest contamination levels for both THBC and TCC, while cucumber showed the lowest. Variations in contamination levels were attributed to environmental factors, inadequate handling practices, and hygiene standards. The study concluded that RTE fruits sold in Port Harcourt pose significant health risks due to microbial contamination levels exceeding recommended safety thresholds. It emphasized the importance of stringent hygiene practices among vendors and better regulatory measures to prevent outbreaks. Recommendations include improved food safety training for vendors, stricter sanitation practices during handling and transportation, and regular monitoring by health authorities to ensure compliance with safety standards. Therefore, the study highlights health risks in consuming ready-to-eat fruits, supporting food safety improvements to reduce foodborne illnesses in Port Harcourt.

An innovative Solar-Power fed atmospheric water Generator: Quantity and quality Assessments

This paper presents the generation of an alternative source of clean water through the Atmospheric Water Generation technique. A customised design using a thermoelectric cooler, powered by a renewable energy source, was used for this purpose. The system is powered by a 65-watt solar panel coupled with piezoelectricity generation utilising the mechanical power of pedestrians. As piezoelectricity production was diminutive, it was only used to supply energy to a low-power appliance. Several customized designs, as well as systematic orientations of the prototype, were examined under varying temperatures and humidity to optimise water production. It is found that the best system configuration can produce about 100 ml of water after 6 h of operation at 66 % average relative humidity and an ambient temperature of 31 °C. The water generation was a complete off-grid solution using solely solar power. As per the accumulated water-to-power input ratio, the proposed system has the maximum water generation capability (0.8333 ml h − 1 W − 1) amongst the contemporary systems. The drinkability of accumulated water samples was tested considering the Heterotrophic Bacterial and total Coliform counts, accompanied by a comparison between tap water and distilled water.

Synergistic use of cattle bile, compost and fertilizer amendments in enhancing the bioremediation of hydrocarbon-contaminated soils

This study investigated the degradation of hydrocarbon-contaminated soil using compost, NPK 20:10:10 fertilizer, and cattle bile as biostimulants. In this study, 1000 g of homogenized contaminated soil was amended with 10.50 g of NPK fertilizer and 107.50 g of compost to achieve a nitrogen concentration of 0.2 %. To establish a 0.4 % nitrogen concentration, 23.90 g of NPK fertilizer, 243.54 g of compost, and 2 ml of cattle bile were used. These amendments were applied in various combinations to create the following microcosm treatments: A, B, C, D, A2, B2, C2, D2, and a control. The microcosms, along with the control were incubated for 6 weeks in triplicate. Throughout this period, several parameters were monitored every two weeks, including pH, nitrogen (N), potassium (K), phosphorus (P), moisture content, organic carbon, organic matter, total heterotrophic bacterial count (THBC), and total petroleum hydrocarbon (TPH) concentration. The results showed significant differences (p < 0.05) in TPH content across the microcosms during the four sampling periods. By the end of the 6-week incubation, the TPH residual concentration varied between 1.58 mg kg-1 and 20.61 mg kg-1, corresponding to degradation rates of 98.43 % and 79.58 %, respectively, from an initial TPH concentration of 100.91 mg kg-1. Microcosm B2 demonstrated the highest hydrocarbon removal efficiency (98.43 %), while the control showed the lowest efficiency. The order of degradation efficiency among the microcosms was B2 > B (94.89 %) > C (94.64 %) > A (94.13 %) > D2 (93.62 %) > A2 (93.51 %) > C2 (92.45 %) > D (91.44 %). The study also found that pH and nitrogen levels were related to the reduction in hydrocarbon content. Microcosms with a 0.4 % nitrogen concentration showed a higher rate of nitrogen consumption compared to those with a 0.2 % concentration. Additionally, changes in pH were observed as hydrocarbon degradation progressed. This study further applied cluster analysis, Bayesian statistics, and multiple linear regression to evaluate the effects of treatments on soil quality over time. Cluster analysis showed increasing dissimilarity between merged clusters, while Bayesian analysis revealed positive trends in parameter estimates in Weeks 2 and 4. Regression analysis indicated significant impacts of Weeks 2, 4, and 6 on Week 0, with F-statistics of 8.475 (p = 0.016), 9.804 (p = 0.004), and 3.759 (p = 0.037), though multicollinearity reduced the predictive power of individual coefficients. Overall, Microcosm B2 emerged as the most effective treatment option. The findings suggest that biostimulation using a combination of moisture, compost, NPK fertilizer, and cattle bile is an effective approach to achieving high efficiency in TPH degradation in hydrocarbon-contaminated soils.

Effect of Pipe Materials and Interspecific Interactions on Biofilm Formation and Chlorine Resistance: Turn Enemies into Friends

Drinking water distribution systems (DWDSs) may be contaminated to various degrees when different microorganisms attach to the pipe walls. Understanding the characteristics of biofilms on pipe walls can help prevent and control microbial contamination in DWDSs. The biofilm formation, interspecific interactions, and chlorine resistance of 10 dual-species biofilms in polyethylene (PE) and cast iron (CI) pipes were investigated in this paper. The biofilm biomass (heterotrophic bacterial plate count and crystal violet) of dual species in CI pipes is significantly higher than that in PE pipes, but the biofilm activity in CI pipes is significantly lower than that in PE pipes. The interspecific interaction of Sphingomonas-containing group presented synergistic or neutral relationship in PE pipes, whereas the interspecific interaction of the Acidovorax-containing group showed a competitive relationship in CI pipes. Although interspecific relationships may help bacteria resist chlorine, the chlorine resistance was more reliant on dual-species groups and pipe materials. In CI pipes, the Microbacterium containing biofilm groups showed better chlorine resistance, whereas in PE pipes, most biofilm groups with Bacillus exhibited better chlorine resistance. The biofilm groups with more extracellular polymeric substance (EPS) secretion showed stronger chlorine resistance. The biofilm in the PE pipe is mainly protected by EPS, while both EPS and corrosion products shield the biofilms within CI pipe. These results supported that dual-species biofilms are affected by pipe materials and interspecific interactions and provided some ideas for microbial control in two typical pipe materials.

Bacteriological Quality Determination of Borehole Water Supply in Hostels of Rivers State University Main Campus, Port Harcourt, Nigeria

Water serves as a vehicle for the transmission of various diseases to man and animals, and have been associated with both acute and chronic health syndromes. This study was carried out to determine the bacteriological quality of borehole water supply in the Hostels of Rivers State University, Port Harcourt, Nigeria. Borehole water samples were collected from six (6) hostels for each study period, and subjected to standard bacteriological Procedures. Results obtained indicated that the highest mean total heterotrophic bacterial count of 3.6±1.7 X 105cfu/ml was recorded in the Hostel C water sample, while the least mean bacterial count of 5.5±0.35 X 104cfu/ml was observed in FCMB Hostel. The total coliform count had the highest value (3.3±3.82 X 104cfu/ml) recorded in Hostel D and the lowest value of 2.0±0.14 X 103cfu/ml was obtained in the Hostel H water sample. The faecal coliform count recorded the highest value in FCMB Hostel (1.5±0.71X 103 cfu/ml) and lowest in Hostel H (8.5±4.95 X 103 cfu/ml). The staphylococcal count was highest in Hostel B (8±9.9 X 104 cfu/ml) and lowest in Hostel C (0.6±0.57 X 104cfu/ml). Six bacterial species were identified, which included Bacillus spp (100%), Staphylococcus spp (100%), Pseudomonas spp (83.3%), Klebsiella spp. (66.6%), Salmonella spp (16.6%) and Escherichia coli (16.6%). Data obtained showed that all the isolates were biofilm producers, albeit at varying percentages, as 52.9%, 55.5%, 60%, 30%, 33.3%, and 100% of Bacillus spp, Staphylococcus spp., Pseudomonas spp., Klebsiella spp., Salmonella spp. and Escherichia coli, respectively were positive for biofilm formation. The hemolysis result indicated that 28.3%, 10%, and 61.7% of the isolates were alpha, beta and gamma hemolytic, respectively. The study indicated the presence of bacteria of public health importance, thereby, making the need for regular monitoring and treatment of these water sources very necessary to check bacterial proliferation and ensure continuous access to safe water in the hostels.

Bacterial Inactivation Studies in Shrimp Pond Water by using Different Disinfectant Agents

Abstract Background Aquaculture water plays an important role in the dissemination of antibiotic-resistant bacteria during harvest of shrimps. Mitigation of bacteria through discharge is essential to prevent dissemination downstream. Chemical disinfection of culture water is feasible compared to other methods of bacterial inactivation. Objective To study the effect of different disinfectant agent’s viz., chlorine, Fenton’s reagent, and hydrogen peroxide (H2O2) on inactivation of bacteria from shrimp pond water Methods The water samples were subjected to treatment with various concentrations of chlorine (0.0, 1.0, 2.5, 5.0 and 10.0 mg L−1), Fenton’s reagent (1:10 mM ratio of Fe2+:H2O2; 2:20, 3:30, 4:40, 5:50) and H2O2 (20, 30, 40 and 50 mM) for different time durations (5 min, 15 min, 30 min and 60 min). Results The results indicated that all the disinfecting agents inactivated both the total heterotrophic bacteria and tetracycline-resistant bacteria with increased concentrations and time. At the end of 60 min treatment with chlorination (2.5 mg Cl2 L−1), Fenton’s reagent (2 mM Fe2+ + 20 mM H2O2) and H2O2 (50 mM H2O2), the total heterotrophic bacterial count in the water samples gradually decreased by 2.35, 2.65, and 1.38 log10 CFU mL−1, and tetracycline-resistant bacteria count reduced by 1.57, 1.66, and 1.43 log10 CFU mL−1, respectively from initial bacterial load. Conclusions The study revealed that disinfection agents can be successfully employed in the inactivation of antibiotic-resistant bacteria discharged through aquaculture water. Among three disinfection agents, Fenton’s reagent has been found effective in inhibiting both heterotrophic bacteria and tetracycline-resistant bacteria from water samples. Highlights Bacterial inactivation studies were carried with Chlorination, Fenton’s reagent, and Hydrogen peroxide. The highest decrease in HPC (2.65 log) and tetracycline-resistant bacterial (1.66 log) was noticed in the water samples treated with Fenton’s reagent. The use of disinfection agents effectively mitigates antibiotic-resistant bacteria from aquaculture wastewater.

Nutritional and Microbial Quality of Locally Processed Plantain Flour

Flour is a fibre rich in carbohydrate but the preparation and packaging process are exposed to microbial contaminations and nutritional alterations. This study was therefore undertaken to evaluate the microbial and nutritional quality of packaged and unpackaged plantain flour. Cultural, microscopic, biochemical test and most probable number (MPN) methods were employed to determine the various microorganisms; while pproximate analysis was done to estimate inherent nutrients in the flour. Significant differences between packaging, nutritional and microbial qualities were determined using ANOVA or T-test, at P&lt;0.05. Results show Heterotrophic bacterial count in packaged plantain flour was 4.52 ± 1.20 x 102 Cfu/g and unpackaged flour 6.01 ± 1.43 x 102 Cfu/g. Coliform bacterial count in plantain flour showed packaged 2.77 ± 2.01 x 102 Cfu/g and unpacked 3,45 ± 0.50 x 102 Cfu/g. The Pseudomonas count showed the packaged plantain flour count of 3.24 ± 0.60 x 102 Cfu/g and the unpackaged 4.31 ± 1.23 x 102 Cfu/g. The proximate analysis of the flour sample revealed an increase in nutritional contents. This study concludes that exposure of flour to the environment increases microbial content and therefore health and hygiene concerns.

Assessment of Bacteriological Quality and Determination of Antibiogram of Bacteria Isolated from Water Used in Selected Hospitals within Port Harcourt City and Obio/Akpor Local Government Area of Rivers State

Study’s Novelty/Excerpt This study investigates the bacteriological quality and antibiogram profiles of water samples from hospitals in Port Harcourt Metropolis, highlighting significant contamination and multi-drug resistance among isolated bacterial species. The research identifies the presence of various bacteria, including Staphylococcus sp., Bacillus sp., and Klebsiella sp., with notable resistance to commonly used antibiotics, underscoring the potential public health risks associated with hospital water sources. This study's findings emphasize the need for rigorous water treatment protocols to ensure safe consumption and reduce the risk of antibiotic-resistant infections in hospital settings. Full Abstract Water is vital for life, and water void of bacterial contamination is vital for hospital consumption and use. This study aimed to determine the bacteriological quality and antibiogram of different water samples in some hospitals within Port Harcourt Metropolis. Water samples were collected in different hospitals in Port Harcourt and Obio/Akpor Local Government Area of Rivers State, Nigeria. Based on water dispensers, outdoor taps, washing hand faucets, and faucets in the toilet and theatre. The bacteriological quality of the water samples, coagulase, haemolysis, biofilm, starch, and antibiogram were determined using standard microbiological procedures. The mean range of the total heterotrophic bacterial, staphylococcal, faecal coliform, and total coliform counts of the water samples were 8.5±0.7×105 to 3.8±2.1×107, 1.2±0.2 to 2.8±0.3×105, 0.0±0.0 to 8.0±4.2×103 and 0.0±0.0 to 1.1±0.1×105 CFU/mL, respectively. The prevalence of the isolated bacteria is Staphylococcus sp (17.5%), Bacillus sp (12.5%), Enterobacter sp. (12.5%), Klebsiella sp. (10%), Citrobacter sp. (5%), Escherichia coli (2.5%) and Siccibacter sp. (2.5%). Staphylococcus, Bacillus, Enterobacter, Klebsiella, Citrobacter, Escherichia coli, and Siccibacter sp. were positive for haemolysis and α-amylase production, 80% of Staphylococcus sp were coagulase positive while 46, 40, 57 and 25% of Staphylococcus, Bacillus, Enterobacter, and Klebsiella sp produced biofilm. The antibiogram showed multi-drug resistance (0.2-1.0). Levofloxacin was 60% effective against Staphylococcus sp, while susceptibility of Klebsiella and Citrobacter sp to ofloxacin, gentamycin, nalidixic acid, and levofloxacin 66.7%. The water samples from these hospitals might not be good for drinking. Thus, treatment of water before use is recommended. The high antibiotic resistance could imply the emergence of resistant isolates in hospital water.

Assessment of Airborne Extended Spectrum β-Lactamase Producing Enterobacteriaceae Isolates from Motor Parks in Benin City, Nigeria

Aim: The study was aimed at assessing airborne bacteria and extended spectrum β-lactamase producing Enterobacteriaceae isolated from the motor parks in Benin City. Methodology: Airborne bacteria samples were collected in the motor parks (Central, Ugbowo, Agip, 19th Street, and Ekosodin Park), in Benin City using the settled plate method on Nutrient and MacConkey agar. Temperature, relative humidity, and airborne bacteria of the different parks were determined. The bacterial isolates were identified using phenotypic method. The antibiotic susceptibility profile was investigated by the disc diffusion method. The Enterobacteriaceae isolates were screened for Extended-spectrum β-lactamase (ESBL) production potentials. Virulence factor analysis and detection of ESBL genes (TEM, CTX-M, SHV, and OXA) were carried out on the selected ESBL producers. Results: The relative humidity recorded at the parks at the point of agar plate exposure ranged from 82 ̶ 90%. The airborne heterotrophic bacterial and coliform counts from the motor parks ranged from 9.50±0.63 × 102 ̶ 1.18±0.02 ×103 cfu/m3 and 2,48±0.41×102 ̶ 3.30±0.41×102 cfu/m3 respectively. The identified Enterobacteriaceae were Citrobacter freundii, Serratia marcescens, Citrobacter koseri, Klebsiella pneumoniae, Morganella morganii, Klebsiella oxytoca, Shigella dysenteriae, Proteus mirabilis, Escherichia coli, Enterobacter cloacae and Citrobacter diversus. The isolate with highest frequency of occurrence was E. coli with values of 30.48 %. The isolate K. pneumoniae had the highest MAR index of 0.8. The isolate S. marcescens had the highest virulent factor of 60% and possessed all the ESBL genes detected. Conclusion: Strong infection control measures should be put in place because more ESBL-producing Enterobacteriaceae have emerged in the surroundings of specific parks in Benin City.

Bio-Prospecting Xylose-Utilizing, Exopolysaccharide (EPS)-Producing Bacteria and EPS Quantification through Submerged Fermentation using Xylose as the Major Carbon Source

Study’s Novelty/ Excerpt This study identified bacterial isolates from diverse environments capable of utilizing xylose for exo-polysaccharide (EPS) production, an area with limited prior research. Potential EPS producers were isolated and identified as Staphylococcus, Enterobacter, Kocuria, Klebsiella, Enterococcus, Serratia, and Burkholderia species using a salt-based medium with xylose as the primary carbon source. The highest EPS production was observed in Enterobacter cloacae D1, E. cloacae D2, Klebsiella oxytoca D2, and K. oxytoca G1, ranging from 0.04 g/L to 2.0 g/L, highlighting these isolates' potential for optimization and application in various industries. Full Abstract Many microorganisms are capable of producing Exo-polysaccharides (EPS) while utilizing simple sugars and hexoses. These EPS found applications in various fields, such as agricultural biotechnology, pharmaceuticals, textiles, and food industries. However, there is a lack of studies on EPS-elaborating bacteria that can utilize pentoses like xylose. Therefore, the utilization of alternative carbon sources for EPS production has become a focus of recent research. This study aimed to prospect bacteria that can utilize xylose for EPS production. Samples from agricultural soil, dump sites, saline soil, cement-contaminated soil, fresh cow milk, cow dung, and yogurt were serially diluted and cultured in a salt-based medium with xylose as the primary carbon source. Slimy and mucoid colonies were selected as potential EPS-producing isolates and identified morphologically and biochemically using the VITEK 2 Automated identification system. The quantification of EPS production by these isolates was conducted through submerged fermentation with xylose as the sole carbon source. The mean heterotrophic bacterial count of xylose-utilizing bacteria ranged from 2.1x106 CFU to 3.5x108 CFU per gram of the samples analyzed. The slimy and mucoid colonies were identified as members of the genera Staphylococcus, Enterobacter, Kocuria, Klebsiella, Enterococcus, Serratia, and Burkholderia. The quantities of EPS produced by the isolates ranged from 0.04 g/L to 2.0 g/L, with E. cloacae D1, E. cloacae D2, K. oxytoca D2, and K. oxytoca G1 elaborating the highest amount of EPS. Bacterial isolates capable of utilizing xylose for EPS production were obtained from various sources, showing potential for further optimization

Full-length 16S rRNA gene sequencing reveals the operating mode and chlorination-aggravated SWRO biofouling at a nuclear power plant.

Reverse osmosis (RO) membrane fouling and biological contamination problems faced by seawater desalination systems are microbiologically related. We used full-length 16S rRNA gene sequencing to assess the bacterial community structure and chlorine-resistant bacteria (CRB) associated with biofilm growth in different treatment processes under the winter mode of a chlorinated seawater desalination system in China. At the outset of the winter mode, certain CRB, such as Acinetobacter, Pseudomonas, and Bacillus held sway over the bacterial community structure, playing a pivotal role in biofouling. At the mode's end, Deinococcus and Paracoccus predominated, with Pseudomonas and Roseovarius following suit, while certain CRB genera still maintained their dominance. RO and chlorination are pivotal factors in shaping the bacterial community structure and diversity, and increases in total heterotrophic bacterial counts and community diversity in safety filters may adversely affect the effectiveness of subsequent RO systems. Besides, the bacterial diversity and culturable biomass in the water produced by the RO system remain high, and some conditionally pathogenic CRBs pose a certain microbial risk as a source of drinking water. Targeted removal of these CRBs will be an important area of research for advancing control over membrane clogging and ensuring water quality safety in the future.

Bacterial diversity of mineral well water from ten sources belonging to the Guarani aquifer system: Assessment by cultivation-dependent and cultivation-independent methods and their correlation with water physicochemical properties

Mineral water must be safe for consumption. The study aimed to assess the bacterial diversity of mineral water samples collected directly from extraction wells through both cultivation-dependent and cultivation-independent analysis and their correlation with physicochemical properties. The physicochemical characterization included the analysis of 40 different minerals and parameters such as pH, conductivity, oxidation-reduction potential (ORP), total dissolved solids (TDS), salinity (PSU), and temperature (T). For the cultivation-dependent analysis, the counts included heterotrophic bacteria at 22 and 36 °C, total coliforms (TC), Escherichia coli (EC), and Pseudomonas aeruginosa (PSA). The cultivation-independent analysis comprised 16 S rRNA metataxonomic data analysis. The pH of the mineral water samples at wells ranged from 5.02 to 6.73 (non-dimensional), conductivity ranged from 20 to 174 μS/cm, ORP varied between 3.1 and 289 mV, TDS ranged from 10 to 87 mg/L, PSU ranged from 0.01 to 0.08 (non-dimensional), and the temperature range was between 19 and 22 °C. The results revealed counts of PSA in the mineral water samples from wells P-01 and P-02, with an average of 0.18 log CFU/250 mL. The samples from well P-09 exhibited average counts of EC at 0.40 log CFU/250 mL (0.5 SD) and TC at 1.00 log CFU/250 mL (0.0 SD). At 36 °C, the heterotrophic bacterial counts in mineral water samples from all wells were <1.0 log CFU/mL. However, at 22 °C, the samples from wells P-01, P-03, and P-04 showed average heterotrophic bacterial counts of 1.11 log (0.03 SD), 1.61 log (0.09 SD), and 1.30 log (0.02 SD) CFU/mL, respectively. The microbiota varied among the analyzed wells, indicating different microbial community profiles likely influenced by the soil microbiota rather than the physicochemical parameters of the well water samples.

Influence of stocking density on the growth, immune and physiological responses, and cultivation environment of white-leg shrimp (Litopenaeus vannamei) in biofloc systems

Biofloc (BF) stands out as a promising system for sustainable shrimp farming. Optimizing various culture conditions, such as stocking density, carbohydrate source, and feeding management, is crucial for the widespread adoption of the BF system. This study compares the growth performance of white-leg shrimp (Litopenaeus vannamei) in culture ponds at low density (LD) with 50 organisms/m2 and high density (HD) with 200 organisms/m2. Post-larvae of white-leg shrimp were stocked for 16 weeks in both LD and HD groups. The LD group exhibited a superior survival rate, growth rate, and feed consumption compared to the HD group. The BF from the LD system recorded a significantly higher protein content (16.63 ± 0.21%) than the HD group (15.21 ± 0.34%). Heterotrophic bacterial counts in water did not significantly differ with stocking density. However, Vibrio count in water samples was higher in the HD group (3.59 ± 0.35 log CFU/mL) compared to the LD group (2.45 ± 0.43 log CFU/mL). The whole shrimp body analysis revealed significantly higher protein and lipid content in the LD group. In contrast, the total aerobic bacterial count in shrimp from the HD group was high, with the identification of Salmonella enterica ssp. arizonae. Additionally, Vibrio counts in shrimp samples were significantly higher in the HD group (4.63 ± 0.32 log CFU/g) compared to the LD group (3.57 ± 0.22 log CFU/g). The expression levels of immune-associated genes, including prophenoloxidase, transglutaminase, penaiedin 3, superoxide dismutase, lysozyme, serine proteinase, and the growth-related gene ras-related protein (rap-2a), were significantly enhanced in the LD group. Conversely, stress-related gene expression increased significantly in the HD group. Hepatopancreases amylase, lipase, and protease were higher in the LD group, while trypsin activity did not differ significantly. Antioxidant enzyme activity (catalase, glutathione, glutathione peroxidase, and superoxide dismutase) significantly increased in the LD group. The histological structure of hepatopancreas, musculature, and female gonads remained similar in both densities. However, negative effects were observed in the gills' histology of the HD group. These results suggest that increasing stocking density is associated with significantly negative biological, microbial, and physiological effects on white-leg shrimp under the BF system.

Antibiotic Resistant and Plasmid Borne Bacteria Associated with Locally Produced Honey in Enugu State, Nigeria

Aim: The aim of this study is to isolate and identify bacteria contaminants present in the honey samples sold in Ogbete market and detect the presence of imipenem resistance genes in the isolates. Place and Duration of Study: A total of four samples were collected from Ogbete market at Zenith bank, Peace mass, Wheelbarrow and Peace park stations between the early hours of the morning (8-9am) within the month of April, 2023. Methodology: Microbiological analysis was carried out on the samples, including antimicrobial susceptibility test using disc diffusion method., after which Molecular analysis involving DNA extraction, PCR and Plasmid Profiling, were carried out. Results: The total mean heterotrophic bacterial count ranged from 0.03±2.5×103cfu/ml to 22.1±25.5×103cfu/ml. The highest total mean heterotrophic bacterial count was recorded in Zenith bank while the lowest was in Peace mass. The bacteria isolated and characterized through morphological and biochemical tests include Escherichia coli (45%) Klebsiella spp. (41%), Staphylococcus spp. (9%) and Streptococcus spp. (5%). Escherichia coli had the highest frequency of occurrence at 45% while Streptococcus spp. had the lowest at 5%. The sensitivity test showed that the isolates with the highest frequency of occurrence, Escherichia coli and Klebsiella spp. posed a high resistance to Imipenem and Nalidixic at 80% while the least resistance was in Levofloxacin at 10% from these two isolates. The gene of interest, BlaIMP was found after PCR assay. Plasmid DNA was further carried out using the alkaline lysis method using the Zymo research kit. All isolates possessed a single plasmid with molecular weight of 23.1kbp. Conclusion: These isolates may undergo horizontal gene transfer and confer resistance to other microorganisms. Thus, there is need for the development of proper measures to counter bacterial contamination of locally produced honey as this poses a threat to public health.

ASSESSMENT OF THE NUTRITIONAL AND MICROBIOLOGICAL QUALITY OF VENDED TIGER NUT (Cyperus esculentus) DRINK IN CHOBA, RIVERS STATE, NIGERIA

The study was aimed at determining the nutritional and microbiological quality of tiger nut milk (Kunun-aya) sold by three vendors for a three-week period in Choba, Rivers State, Nigeria. Standard methods were employed in determining the proximate, mineral composition, total heterotrophic bacterial counts and presence of Staphylococcus and Escherichia species. Moisture content was consistently highest, ranging from 78.04±2.24 to 87.34±1.24, followed by carbohydrate (7.41±1.88 to 15.14±2.33) and the least was ash (0.11±0.03 to 0.26±0.14). The most abundant of the five minerals was potassium (K) with values ranging from 837.98±15.26 to 931.43±33.30, followed by sodium (Na) with values ranging from 587.39±15.58 to 663.78±34.65 and the least was iron (Fe) with values ranging from 8.50±3.57 to 13.44±3.47. Microbial counts results reveal the following for total heterotrophic bacteria (1.4 to 9.5×107 cfu/ml), Staphylococcus (1.6×103 to 5.5×104 cfu/ml) and Escherichia spp. (0 to 5×103 cfu/ml). The results obtained in this study has revealed the presence of valuable nutrient needed for healthy living as well as high microbial loads and presence of etiologic agents of human infections in vended tiger-nut milk sold in Choba. This underscores the need for the milk to be aseptically prepared to forestall the transmission of pathogenic bacteria to consumers.

Effect of ginger on the quality attributes of pineapple juice during storage

Homemade pineapple juice usually prepared without pasteurization and stored at room temperature could significantly influence the quality of the juice. This study aimed at assessing the effect of ginger (Zingiber officinale Rosc.) on bacteriological, physicochemical and nutritional quality of pasteurized and unpasteurized pineapple juice during storage at ambient temperature (28±2 oC) for 7 days. Unpasteurized; pineapple juice + 10 ml ginger; pineapple juice + 20 ml ginger; pineapple juice + 10 ml ginger; pineapple juice (control) were evaluated. The results obtained showed that total heterotrophic bacterial count, pH, titratable acidity and total soluble solids of the samples treated with ginger were within the range of 2.23-4.60 log10CFU/mL, 4.0-4.9, 0.51-1.86 g/l and 6.9-13.4 % while the corresponding values for the control was 2.0-4.14 log10CFU/mL, 3.5-4.8, 0.63-1.5 g/l, and 9.1-13.2 %, respectively. All the pineapple juice preparations met the National Agency for Food Drug Administration and Control (NAFDAC) requirements. The sample that had the highest vitamin C and ash content was unpasteurized pineapple juice mixed with 30 mL of ginger (7.46 mg/10 mL) and the control which was pasteurized (4.3 %) respectively. Based on the results obtained from this study, pasteurization of pineapple juice as well as addition of ginger to the juice are recommended for the production of a safe product for human consumption

Molecular Characterization and Evaluation of Antibiotic Resistance Gene of Bacteria Associated with Gills of Arius heudelotii and Clarias gariepinus

This study was aimed at the isolation and molecular characterization of bacteria associated with catfish from culture and wild environments. Samples of gills of Arius heudelotii and Claris gariepinus fishes of economic value from the New Calabar River Choba and earthen ponds from Aluu in Rivers State were collected and analysed. Characterization of isolates from the gills of the catfish was done using the 16S rRNA gene sequencing method to identify their relationship. The presence of a resistance gene was examined by polymerase chain reaction followed by agarose gel electrophoresis of the amplification products. The mean total heterotrophic bacterial counts was 6.5995±0.947 LogCFU/g for the gills’ samples obtained from the earthen pond Aluu. New Calabar River had 4.5041±1.054 LogCFU/g for the gills’ samples. A total of 12 bacterial flora were isolated from the gills of the sampled catfish: Escherichia coli, Klebsiella spp., Enterobacter spp., Citrobacter spp., Bacillus subtilis, Proteus vulgaris, Streptococcus spp., Shigella spp. Staphylococcus spp., Micrococcus spp., Vibrio spp. and Acinetobacter spp. Vibrio azureus, Aeromonas dhakensis, Proteus vulgaris, Aeromonas hydrophila. Vibrio azureus and Providencia alcalifaciens were found to be carriers of the TEM gene, while Providencia alcalifaciens carried the CTX-M gene. SHV gene was found in Vibrio azureus, Providencia alcalifacians, Proteus vulgaris, Aeromonas hydrophila, Providencia alcalifacians. However, the Oxa gene was not identified in the bacterial genera. The high probability of transferring them to other microbes to cause antibiotic pollution has become a serious public health challenge. Microbial loads with high or low presence of some potential pathogens call for public concern.