Bacterial Quality Research Articles

Bacterial Quality Assessment of Lake Nasser Sediments During the Drought and Flooding Seasons

Bacterial Quality Assessment of Lake Nasser Sediments During the Drought and Flooding Seasons

Comparison of the DNBSEQ platform and Illumina HiSeq 2000 for bacterial genome assembly

The Illumina HiSeq platform has been a commonly used option for bacterial genome sequencing. Now the BGI DNA nanoball (DNB) nanoarrays platform may provide an alternative platform for sequencing of bacterial genomes. To explore the impact of sequencing platforms on bacterial genome assembly, quality assessment, sequence alignment, functional annotation, mutation detection, and metagenome mapping, we compared genome assemblies based on sequencing of cultured bacterial species using the HiSeq 2000 and BGISEQ-500 platforms. In addition, simulated reads were used to evaluate the impact of insert size on genome assembly. Genome assemblies based on BGISEQ-500 sequencing exhibited higher completeness and fewer N bases in high GC genomes, whereas HiSeq 2000 assemblies exhibited higher N50. The majority of assembly assessment parameters, sequences of 16S rRNA genes and genomes, numbers of single nucleotide variants (SNV), and mapping to metagenome data did not differ significantly between platforms. More insertions were detected in HiSeq 2000 genome assemblies, whereas more deletions were detected in BGISEQ-500 genome assemblies. Insert size had no significant impact on genome assembly. Taken together, our results suggest that DNBSEQ platforms would be a valid substitute for HiSeq 2000 for bacterial genome sequencing.

Peptidyl-tRNA hydrolase is the nascent chain release factor in bacterial ribosome-associated quality control

Rescuing stalled ribosomes often involves their splitting into subunits. In many bacteria, the resultant large subunits bearing peptidyl-tRNAs are processed by the ribosome-associated quality control (RQC) apparatus that extends the C termini of the incomplete nascent polypeptides with polyalanine tails to facilitate their degradation. Although the tailing mechanism is well established, it is unclear how the nascent polypeptides are cleaved off the tRNAs. We show that peptidyl-tRNA hydrolase (Pth), the known role of which has been to hydrolyze ribosome-free peptidyl-tRNA, acts in concert with RQC factors to release nascent polypeptides from large ribosomal subunits. Dislodging from the ribosomal catalytic center is required for peptidyl-tRNA hydrolysis by Pth. Nascent protein folding may prevent peptidyl-tRNA retraction and interfere with the peptide release. However, oligoalanine tailing makes the peptidyl-tRNA ester bond accessible for Pth-catalyzed hydrolysis. Therefore, the oligoalanine tail serves not only as a degron but also as a facilitator of Pth-catalyzed peptidyl-tRNA hydrolysis.

La calidad higiénica de la leche cruda destinada al consumo humano en Argelia: Metaanálisis

The main goal of this article was to conduct a meta–analysis, to estimate the hygienic quality of the raw milk intended for human consumption and subsequently relative risk factors that may impact milk quality in Algeria. Weighted random–effects meta–analysis models were employed to analyze the data in this study. A total of 4,685 sampling results from 61 included studies, investigating the bacterial quality of raw milk across 35/48 Provinces in Algeria, from 2009 to 2022. In this meta–analysis, the average level of contamination by Total Aerobic Mesophilic Bacteria (TAMB) was 5.84 log10 CFU·mL-1. 95% CI [5.55–6.13]. The P–value was 0.001. The I2 test indicates the presence of substantial statistical heterogeneity across studies; (I2=86.26%, P<0,001). No significant publication bias was observed using the funnel plots and Egger’s test (P=0.885). In this article TAMB values did not differ significantly among species (P>0.05).The average contamination level TAMB was lower in milk samples collected from individual milking and farm tank milk (4.57 log10 CFU·mL-1 and 5.89 log10 CFU·mL-1), compared to those recorded in milk samples collected from the collector, dairy, and sales (6.59 log10 CFU·mL-1, 6.60 log10 CFU·mL-1, and 6.74 log10 CFU·mL-1, respectively). The contamination level of milk by TAMB was higher during summer and spring (6.80 log10 CFU·mL-1 and 6.70 log10 CFU·mL-1), compared to winter and autumn (4.27 log10 CFU·mL-1 and 5.64 log10 CFU·mL-1).

Bacterial Quality and Molecular Detection of Food Poisoning Virulence Genes Isolated from Nasser Lake Fish, Aswan, Egypt.

The microbial analysis of fish is critical for ensuring overall health. Uncooked fish can serve as a conduit for transmitting several types of microbes; the current investigation sought to assess the bacterial levels in various kinds of fish from Nasser Lake, Aswan, Egypt, considered the chief source of potable water in Egypt. Two hundred and fifty fish samples, including 50 of each Oreochromis niloticus, Sander lucioperca, Lates niloticus, Clarias gariepinus, and Mormyrus kannume, from Nasser Lake, Aswan, Egypt, were collected to detect the bacterial load, isolation, and identification of Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio parahaemolyticus and their virulence genes. The findings revealed that Oreochromis niloticus and Clarias gariepinus exhibited higher bacterial loads than other fish species. Incidences of bacterial contamination among examined fishes were 28.8%, 20.4%, and 16% for Aeromonas hydrophila, Pseudomonas aeruginosa, and Vibrio parahaemolyticus, respectively. Additionally, PCR analysis detected the presence of aerA (60%) and Act (40%) genes in A. hydrophila, rpoB (70%) and LasB (30%) genes in P. aeruginosa, and ToxR (70%) and tdh (50%) genes in V. parahaemolyticus. The study suggested that the bacterial contamination levels in Oreochromis niloticus and Clarias gariepinus could be notably more significant than in other species that could potentially be harmful to the consumers, especially considering the identification of particular bacteria known to cause foodborne illnesses. Further recommendations emphasized that regular monitoring and assessments are required to preserve their quality.

Radiation processing of dried Ker (Capparis deciduas): Effect on microbial safety and nutritional quality

Radiation processing of fresh and market (0-6 months old) dried ker at different doses of 2.5, 5.0 and 7.0 kGy was investigated. The effect of radiation treatment on total bacterial counts and nutritional quality parameters like moisture, protein, fat, ash, fibre, total sugar and starch contents were determined over a storage period of 3 months at ambient temperature. The findings of the study indicated that the radiation treatment reduces total bacterial counts in both fresh and market-dried ker at all doses. However, a dose of 5 kGy eliminated total bacterial counts in samples after storage. No significant changes were found in the proximate composition of both fresh and market-dried ker. On the contrary, total sugar content was observed to be increased in both control as well as irradiated samples during storage. Thus, radiation processing with 5.0 kGy did not affect significantly the nutritional quality of fresh and market-dried ker samples.

Assessing Environmental and Feed Quality in Southeast Livestock Production

Livestock production has thrived and sustained the livelihood of farmers while reducing poverty and improving the economy of developing nations. It has also contributed largely to the spread of pathogenic bacteria. This study evaluated the bacterial quality of air, water, soil, feed samples, and hand swabs in Aba, Umuahia, Mbaise, and Okigwe in Southeastern Nigeria. Air, water, soil, feeds, and hand swabs were sampled using standard microbiology laboratory procedures. Air samples were expressed in CFU/plate/hour while water, soil, feed and hand swabs were expressed in CFU/ml. Total heterotrophic bacterial count (THBC), total coliform count (TCC), and total potential pathogenic bacterial count (TPPBC) were all analyzed by growing the samples on general purpose, differential, and selective media after serial dilution respectively. Isolates were confirmed by subjecting them to biochemical tests. The highest THBC, TPPBC, and TCC values were obtained in the Aba pig farm, cow abattoir, and poultry farms respectively while Mbaise recorded the lowest values for THBC, TPPBC, and TCC. A total of 1531 bacterial isolates were obtained in all the four cities. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Salmonella enterica, Streptococcus poygenes, Vibrio cholerae and Shigella sp. were isolated. Escherichia coli had the highest total percentage distribution (16.9%; 259/1531) in all four cities and Shigella sp (4.8%; 74/1531) was the least distributed. Of the four cities studied, Aba farm had the highest percentages of E. coli (31.66%; 82/259), K. pneumoniae (31.19%;68/218), P. aeruginosa (30.28%; 43/142), E. aerogenes (31.85%; 43/135) and S. pyogenes (36.57%; 49/134). Among the bacterial isolates, Streptococcus enterica had the highest percentage values (42.38%; 64/151) while Shigella sp had the lowest percentage values (12.16%; 9/74). Overall, the bacterial burden in all the farms in the four cities, especially Aba was very high; thorough surveillance by health workers should be encouraged to help reduce the spread of bacteria and bacterial infections among livestock farms.

Assessment of bacterial loads and water quality parameters of three different types of fish pond

The present study was conducted to determine bacterial loads in the water columns and mud of three different pond systems,includingan overwintering fish fry pond,a brood fish rearing pond, anda recreational fish pond (L-shaped fish pond) situated at the Field Laboratory Complex of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh.Three samplings were done atevery 15-day interval. Bacterial loads in water columns and mud were determined using the drop count method. Water quality parameters, including temperature, dissolved oxygen, pH, and ammonia, were also determined. Significantly (p<.001),the highest bacterial loads in three different water columns were observed in the overwintering fish fry pond, and the lowest bacterial loadswere found in the L-shaped fish pondat all sampling points. Bacterial loads in the bottom water were also significantly higher than those in the surface and middle layers of the water in all ponds. Pond mud was significantly (p<.001) richer in bacterial loads than pond water. Bacterial load was strongly correlated with temperature, and the correlation faded with the increase in depth of the water column.

Co-digestion of chicken manure and sewage sludge in black soldier fly larvae bioconversion system: bacterial biodiversity and nutrients quality of residues for biofertilizer application.

Black soldier fly larvae (BSFL) bioconversion system is emerging as an effective approach for organic waste pollution treatment. Co-digestion of different organic matters with BSFL can be an effective way to realize the innovative biowaste circular economy. In this study, organic waste mixture of chicken manure and sewage sludge was chosen as substrate for BSFL growth. The bacterial biodiversity and nutrients quality of BSFL residue were evaluated through gene sequencing and other characterizations to confirm their application potential as biofertilizers. The dominant bacteria in BSFL residue were Firmicutes (75.39%) at phylum level, Bacilli (71.61%) at class level and Pseudogracilibacillus (11.08%) at genus level. Antibiotic resistance genes (ARGs) were used to assess the harmlessness of BSFL residue. After BSFL treatment, 36.2% decrease in ARGs was observed. Taking nutrients quality into consideration, dissolved organic carbon, dissolved nitrogen, available phosphorous, and available potassium significantly increased in the co-digestion system. These results demonstrated that co-digestion of chicken manure and excess sludge in BSFL bioconversion system could improve the nutrients quality of residues. However, removal of ARGs in the bioconversion process should be further explored to eliminate environmental concerns associated with application of BSFL residue as biofertilizers.

The Effect of Plasma-Activated Water Combined with Rosemary Extract (Rosmarinus officinalis L.) on the Physicochemical Properties of Frankfurter Sausage during Storage.

This study investigated the impact of plasma-activated water (PAW) and rosemary extract on the bacterial inactivation and quality attributes of Frankfurter sausages during a 6-day storage period. The antibacterial activity, total phenol content (TPC), and total flavonoid content (TFC) of the rosemary extract were evaluated. The TPC of the rosemary extract was 89.45 mg gallic acid/g dry weight, while the TFC was 102.3 mg QE/g dry weight. Even at low concentrations, the rosemary extract effectively inhibited the growth of all the tested pathogens using the Well Diffusion Agar method (WDA). The sausages were treated with different concentrations of PAW and rosemary extract and stored for 1 and 6 days. Sample B (100% rosemary extract + PAW treatment) showed the greatest reduction in microbial load and was selected for further analysis. Throughout the storage period, Sample B exhibited no significant changes in pH, moisture content, textural parameters, or sensory evaluation compared to the control group. However, the hardness and color parameters (L*, a*) of Sample B decreased, while the TBARS value increased after 6 days of storage. The combination of PAW and rosemary extract, particularly Sample B, effectively inhibited bacterial growth in the Frankfurter sausages without compromising most quality attributes. Some changes in hardness, color, and lipid oxidation were observed over the extended storage period.

Comparison of UV-LED treatments at 255 and 281 nm in continuous-flow on bacterial inactivation, quality, nutrients and electrical efficiency in beverages

Ultraviolet light emitting diodes (UV-LEDs) have emerged as an alternative UV source. We compared the treatment of coconut water (CW), blue lemonade (BL) and ascorbic acid (AA) solution at 255 and 281 nm UV-LEDs in continuous-flow in terms of bacterial inactivation and effects on physical, quality and nutritional parameters and electrical efficiency. A 5-log10 reduction of Escherichia coli was achieved in CW and BL at both wavelengths. At similar fluence levels, a decrease in absorption coefficient (CW and BL), ascorbic acid and antioxidants (CW) was observed at both wavelengths. An increase in colour lightness of BL was observed at 281 nm. Treatment with 281 nm was more electrically efficient at achieving a 5-log10 reduction in beverages compared to 255 nm. This was confirmed in AA solution where 281 nm showed less photo-oxidation compared to 255 nm. Use of UV-LEDs allows for selection of optimal wavelengths to achieve higher microbial and electrical efficiency while maintaining product quality.

Bacteriological Analysis of Well Water Obtained from Onueke Metropolis, Ezza South Local Government Arae, Ebonyi State, Nigeria

Many households in Nigeria are dependent on alternative sources of water supply and are exposed to preventable water-borne diseases. This study was carried out to examine the bacterial quality of well water obtained from Onueke metropolis in Ebonyi State. The physicochemical parameters of water samples collected from 25 closed and 25 opened wells were analyzed following standard procedures while bacteriological quality of the water samples including coliform count and bacterial isolate identification were determined using serial dilution and multiple fermentation techniques. Results of the physiochemical parameters showed that pH, Electrical Conductivity, Total Hardness, Turbidity and nitrite were within the WHO standard limit for drinking water. The bacterial count ranged from 0.8 – 3.1 x 104 CFU /100ml involving E. coli (25%), Shigella spp (12.5%), Citrobacter spp (4.2%), Klebsiella spp (29.2%), Enterobacter spp (12.5%) and Salmonella spp (16.7%) as the dominant isolates and exceeded the WHO guidelines limit of 0 cfu/100ml for drinking water. Generally, the uncovered wells were more highly contaminated with bacteria pathogens than the covered wells. All samples were above the most probable number (MPN) per 100 ml permissible limit of WHO guidelines for untreated drinking water. In conclusion sampled well water from Onueke metropolis contained bacterial contaminants making the water not safe for drinking devoid of any further water treatment process.

Antibiotic and Heavy Metal Resistance Patterns of Indicator Bacteria in Surface Water Bodies of Kilis

The surface waters contaminated with coliform bacteria having antibiotic and heavy metal resistance have become an increasing public health risk. For this reason, it is aimed to detect the bacterial quality, the frequency of antibiotics, heavy metal resistance, and bioindicator bacteria in surface water sources taken from Kilis. The resistance profile of sixteen bacteria species belonging to class Gammaproteobacteria to standard antibiotics and heavy metal salts was investigated using Kirby-Bauer disc diffusion techniques. The various physicochemical parameters such as total dissolved solids (TDS), electrical conductivity (EC), pH, temperature, dissolved oxygen amount, and biochemical oxygen demand (BOD) of samples were also examined. The total coliform load was recorded as˃1100 (MPN)/100 mL and calculated comparatively lower values (53(MPN)/100 mL) of fecal contamination for both stations. A high level of resistance to clindamycin in a total of 16 strains was observed. Ampicillin (56.25%), cefotaxime (37.5%), and ceftazidime (31.25%) followed them. The trends in heavy metal resistance of isolates increased in the order of Cd2+< Pb2+

Antibiotics can alter the bacterial extracellular polymeric substances and surface properties affecting the cotransport of bacteria and antibiotics in porous media

Currently, studies on the environmental impact of antibiotics have focused on toxicity and resistance genes, and gaps exist in research on the effects of antibiotics entering the environment on bacterial surface properties and the synergistic transport of antibiotics and bacteria in porous media. To fill the gaps, we investigated the interactions between bacteria and antibiotics in synergistic transport in saturated porous media and the effects of media particle size, flow rate, and ionic concentration on this synergistic transport. This study revealed that although synergistic transport was complex, the mechanism of action was clear. Antibiotics could affect bacterial extracellular polymeric substances (EPS), thus altering their surface hydrophobicity and roughness, thereby affecting bacterial transport. The effects of antibiotics on bacterial transport were dominated by altering bacterial roughness. Antibiotics had a relatively high adsorption on bacteria, so bacterial transport directly affected antibiotic transport. The antibiotic concentrations below a certain threshold increased the bacterial EPS quality, and above the threshold decreased the bacterial EPS quality. This threshold was related to antibiotic toxicity and bacterial type. Bacterial surface hydrophobicity was determined by the combination of proteins and sugars in the EPS, and roughness was positively correlated with the EPS quality.

The Impact of HPP-Assisted Biocontrol Approach on the Bacterial Communities' Dynamics and Quality Parameters of a Fermented Meat Sausage Model.

Traditional foods are increasingly valued by consumers, whose attention and purchase willingness are highly influenced by other claims such as 'natural', 'sustainable', and 'clean label'. The purpose of the present study was to evaluate the impact of a novel non-thermal food processing method (i.e., HPP-assisted biocontrol combining mild high hydrostatic pressure, listeriophage Listex, and pediocin PA-1 producing Pediococcus acidilactici) on the succession of bacterial communities and quality of a fermented sausage model. A comparative analysis of instrumental color, texture, and lipid peroxidation revealed no significant differences (p > 0.05) in these quality parameters between non- and minimally processed fermented sausages throughout 60-day refrigerated storage (4 °C). The microbiota dynamics of biotreated and untreated fermented sausages were assessed by 16S rRNA next-generation sequencing, and the alpha and beta diversity analyses revealed no dissimilarity in the structure and composition of the bacterial communities over the analyzed period. The innovative multi-hurdle technology proposed herein holds valuable potential for the manufacture of traditional fermented sausages while preserving their unique intrinsic characteristics.

Determination of Bacterial Quality of Indoor Air of Health Centers around Georgetown

Health centers around Georgetown, Guyana, are bisected with myriads of problems such as inadequate sanitation protocols and physical and environmental factors that contribute to the rise of nosocomial infections. The aim of this study was to conduct a bacteriological assessment of indoor air in three health centers around Georgetown, Guyana. This research was conducted under a cross-sectional study design for a period of one month. Nutrient agar plates were exposed for 30 minutes twice a day over three days. Subsequently, plates were incubated at 37℃ for 24-48 hours, and the number and types of bacteria were determined. The average bacterial load during the morning was 2226.33 cfu/ m3 and 2032.33 cfu/m3 in the afternoon at health center 1. At health center 2, the average bacterial load was 859 cfu/ m3 in the morning and 755.75 cfu/ m3 in the afternoon. At Health Center 3, the bacterial averages were 807.67 cfu/ m3 and 1317.59 cfu/ m3 for morning and afternoon sampling times, respectively. Isolated bacteria were identified by morphological characteristics, gram staining and biochemical tests were also carried out. The bacterial isolates included Escherichia coli, Serratia marcescens, Micrococcus spp., Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus spp., Proteus spp., Pseudomonas aeruginosa, and Enterobacter aerogenes. Favorable conditions and environmental factors for the growth and multiplication of bacterial microbes in the air, like ventilation, lower temperature, poor sanitation, sanitation, attached toilets, and frequency of persons present, were observed during the survey. The findings contribute to an array of nosocomial infections that can be detrimental in severe cases.

Water quality in rural Greenland - acceptability and safety

The low proportion of households with piped drinking water in Greenlandic settlements – and elsewhere in the Arctic, leads to improvised methods of household water storage and water saving practices that could present a risk for public health.This interview-based study investigated the perceptions of safety and acceptability of the water supply in rural Greenlandic households. The bacterial quality of the water distributed by the public supply before and after storage in the homes, of alternative water sourced from nature by the users themselves, and of shared handwash basins used in un-piped homes, was analyzed.The treated water distributed by the rural Greenlandic water supply was acceptable to most users, although half of them expressed concerns about its quality, and distrusted the state of the infrastructure delivering piped water. For drinking, most respondents preferred untreated water from nature, but a majority used mainly piped water for practical reasons of access. The microbial quality of the public water supply met legislative requirements in most cases, but was found to deteriorate during both distribution to some taps, and storage in the homes, which constitutes a challenge to the reliable provision of safe water to users. Water from alternative sources showed slightly higher heterotrophic plate counts (HPC) than piped water, but no Escherichia coli. As for washbasins, they were found to have high levels of contamination in all three bacterial parameters investigated (HPC, coliforms and E. coli), indicating a possible transmission route for pathogens.In conclusion, while the quality of treated water was overall good at distribution, the water saving and storage practices developed to compensate for the lack of piping may threaten public health. Alternative water sources are culturally important and trusted by users, although the possible impact of changes in climate and land use on the reliability of their quality is unknown.

Alternations of ensiling performance and bacterial community in response to different native grassland in Mongolian Plateau

The aim of this study was to investigate the dynamics of bacterial communities and natural fermentation quality in three steppe types [meadow steppe (MS); typical steppe (TS); and desert steppe (DS)] on the Mongolian Plateau. PacBio single molecule with real-time sequencing technology was applied to provide insights into the dynamics of the physicochemical characteristics and the complex microbiome of native grass after 1, 7, 15, and 30 days of fermentation process. The dry matter, crude protein, and water soluble carbohydrate (WSC) contents of the three groups slowly decreased after 1 day of fermentation process, and the lowest WSC concentration after 30 days of ensiling was detected in the DS group compared to that in the MS and TS groups. There was no significant effect of steppe types on lactic acid and butyric acid content (P>0.05). The pH was higher in the early stages of fermentation. After 30 days of fermentation, the pH of MS and DS dropped to ∼5.60, while TS was as high as 5.94. At different ensiling days, the pH of TS was significantly higher than that of MS (P<0.05). The ammonia nitrogen content of MS was significantly higher than TS and DS (P<0.05). During the whole fermentation process, Leuconostoc mesenteroides and Pseudocitrobacter faecalis were the main species of DS, while Enterobacter roggenkampii and Faecalibacterium prausnitzii dominated the fermentation process in MS and TS, respectively. The fermentation quality of native grass silage of different steppe types was less satisfactory, with the silage quality ranging from DS, MS, and TS in descending order. The epiphytic bacteria dominating the fermentation process differed between steppe types of silage. Leuconostoc mesenteroides as the main strain of DS had a modulating effect on pH and LA content, while the main strains of MS and TS (Enterobacter roggenkampii and Faecalibacterium prausnitzii) dominated the silage without significant effect on improving fermentation characteristics and nutritional quality.

The effects of novel alginate-lauric arginate coatings with temperature on bacterial quality, oxidative stability, and organoleptic characteristics of frozen stored chicken drumsticks

Although alginate has been reported to be used as an edible film and coating in food, to the best of our knowledge, this study is the first to investigate the individual effects of coatings, temperatures, storage times, as well as their interactions, on the bacterial quality, deterioration criteria, and sensory attributes of chicken drumsticks. To accomplish this, six groups of chicken drumsticks were treated with different coatings, temperatures, and storage conditions. The groups included 2 % alginate at 25 °C (Alg25) and 50 °C (Alg50), a mixture of 2 % alginate and 2 % LAE at 25 °C (M25) and 50 °C (M50), besides control untreated samples in distilled water at 25 °C (C25) and 50 °C (C50). The chicken drumsticks were stored at −18 °C for 3 months. The results showed that all treated chicken drumsticks induced a significant reduction in all bacterial counts, as well as a significant decrease in pH and thiobarbituric acid values, with an improvement in all sensory attributes, particularly in the M25 and M50 coated samples compared to the C25 and C50. Furthermore, exposing alginate and LAE to a temperature of 50 °C can increase their antimicrobial activity. In conclusion, the innovative combinations of LAE and alginate can be used successfully to decontaminate chicken carcasses in poultry processing plants.

Distribution of Antibiotic Resistance Genes and Their Associations with Bacterial Communities and Water Quality in Freshwater Lakes

Distribution of Antibiotic Resistance Genes and Their Associations with Bacterial Communities and Water Quality in Freshwater Lakes