Bacterial biofilms are complex surface attached communities of bacteria held together by self-produced polymer matrixs mainly composed of polysaccharides, secreted proteins, and extracellular DNAs. ...Bacterial biofilm formation is a complex process and can be described in five main phases: (i) reversible attachment phase, where bacteria non-specifically attach to surfaces; (ii) irreversible attachment phase, which involves interaction between bacterial cells and a surface using bacterial adhesins such as fimbriae and lipopolysaccharide (LPS); (iii) production of extracellular polymeric substances (EPS) by the resident bacterial cells; (iv) biofilm maturation phase, in which bacterial cells synthesize and release signaling molecules to sense the presence of each other, conducing to the formation of microcolony and maturation of biofilms; and (v) dispersal/detachment phase, where the bacterial cells depart biofilms and comeback to independent planktonic lifestyle. Biofilm formation is detrimental in healthcare, drinking water distribution systems, food, and marine industries, etc. As a result, current studies have been focused toward control and prevention of biofilms. In an effort to get rid of harmful biofilms, various techniques and approaches have been employed that interfere with bacterial attachment, bacterial communication systems (quorum sensing, QS), and biofilm matrixs. Biofilms, however, also offer beneficial roles in a variety of fields including applications in plant protection, bioremediation, wastewater treatment, and corrosion inhibition amongst others. Development of beneficial biofilms can be promoted through manipulation of adhesion surfaces, QS and environmental conditions. This review describes the events involved in bacterial biofilm formation, lists the negative and positive aspects associated with bacterial biofilms, elaborates the main strategies currently used to regulate establishment of harmful bacterial biofilms as well as certain strategies employed to encourage formation of beneficial bacterial biofilms, and highlights the future perspectives of bacterial biofilms.
Insect and mite pests are damaging stressors that are threatening the cultivation of tea plants, which result in enormous crop loss. Over the years, the effectiveness of synthetic pesticides has ...allowed for its prominent application as a control strategy. However, the adverse effects of synthetic pesticides in terms of pesticide residue, environmental contamination and insect pest resistance have necessitated the need for alternative strategies. Meanwhile, microbial pesticides have been applied to tackle the damaging activities of the insect and mite pests of tea plants, and their performances were scientifically adjudged appreciable and environmental friendly. Herein, entomopathogenic microbes that were effective against tea geometrid (
Ectropis obliqua
Prout), tea green leafhopper (
Empoasca onukii
Matsuda), paraguay tea ampul (
Gyropsylla spegazziniana
), tea mosquito bug (
Helopeltis theivora
Waterhouse) and red spider mite (
Oligonychus coffea
Nietner) have been reviewed. The current findings revealed that microbial pesticides were effective and showed promising performances against these pests. Overall, this review has provided the basic and integrative information on the integrated pest management (IPM) tool(s) that can be utilized towards successful control of the aforementioned insect and mite pests.
Graphic abstract
Abstract
As the coronavirus disease 2019 (COVID-19) pandemic continues to rise and second waves are reported in some countries, serological test kits and strips are being considered to scale up an ...adequate laboratory response. This study provides an update on the kinetics of humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and performance characteristics of serological protocols (lateral flow assay LFA, chemiluminescence immunoassay CLIA and ELISA) used for evaluations of recent and past SARS-CoV-2 infection. A thorough and comprehensive review of suitable and eligible full-text articles was performed on PubMed, Scopus, Web of Science, Wordometer and medRxiv from 10 January to 16 July 2020. These articles were searched using the Medical Subject Headings terms ‘COVID-19’, ‘Serological assay’, ‘Laboratory Diagnosis’, ‘Performance characteristics’, ‘POCT’, ‘LFA’, ‘CLIA’, ‘ELISA’ and ‘SARS-CoV-2’. Data from original research articles on SARS-CoV-2 antibody detection ≥second day postinfection were included in this study. In total, there were 7938 published articles on humoral immune response and laboratory diagnosis of COVID-19. Of these, 74 were included in this study. The detection, peak and decline period of blood anti-SARS-CoV-2 IgM, IgG and total antibodies for point-of-care testing (POCT), ELISA and CLIA vary widely. The most promising of these assays for POCT detected anti-SARS-CoV-2 at day 3 postinfection and peaked on the 15th day; ELISA products detected anti-SARS-CoV-2 IgM and IgG at days 2 and 6 then peaked on the eighth day; and the most promising CLIA product detected anti-SARS-CoV-2 at day 1 and peaked on the 30th day. The most promising LFA, ELISA and CLIA that had the best performance characteristics were those targeting total SARS-CoV-2 antibodies followed by those targeting anti-SARS-CoV-2 IgG then IgM. Essentially, the CLIA-based SARS-CoV-2 tests had the best performance characteristics, followed by ELISA then POCT. Given the varied performance characteristics of all the serological assays, there is a need to continuously improve their detection thresholds, as well as to monitor and re-evaluate their performances to assure their significance and applicability for COVID-19 clinical and epidemiological purposes.
Rift Valley fever (RVF) is an emerging mosquito-borne zoonosis that threatens public health and animal agriculture in the endemic areas causing devastating epizootics characterized by abortion storms ...and high mortalities, especially in newborn animals. A cross-sectional study was conducted to determine the seroprevalence and investigate risk factors associated with exposure to the virus in camels slaughtered in Maiduguri abattoir, Borno State of Nigeria. Camels presented for slaughtered were sampled and data on age, sex, source or origin, utility, presence of post-mortem lesions, body weights and body condition score were collected. Blood samples were collected and sera were harvested and stored at – 20 °C until tested. The sera were tested using a commercial ELISA kit based on the manufacturer’s instructions. The overall seroprevalence in the study was 20.7% (95% CI, 13.6–30.0). The analysis showed no significant differences between the presence of antibodies and variables that included the sex of camels (
χ
2
= 0.015, df = 1,
p
= 0.904) and the presence of post-mortem lesion on the carcass (
χ
2
= 0.009, df = 1,
p
= 0.925). There were significant differences between presence of antibodies and three variables that included the age (
χ
2
= 4.89, df = 1,
p
= 0.027), the source (
χ
2
= 7.077, df = 2,
p
= 0.029) and the main utility (
χ
2
= 8.057, df = 3,
p
= 0.045) of the camels. It was concluded that camels presented for slaughter at the Maiduguri abattoir have evidence of exposure to the RVF virus and maybe means of transmission of the virus. Regular monitoring and control of transboundary animal movements were recommended in the study area.
Abstract Background Client satisfaction is a multidimensional construct focusing on clients’ perceptions and evaluations of the treatment and care received. It is one of the factors affecting the ...outcomes of healthcare and the use of health services. Therefore, we aimed to assess clients’ satisfaction with PHC services in Kaduna State, Northwest Nigeria. Methodology A cross–sectional descriptive study was conducted in Kaduna State, Northwest, Nigeria which evaluate the satisfaction of clients and caregivers accessing healthcare in PHC centres. A sample size of 217 was determined using Fisher’s formula, with a multi-stage sampling technique used to randomly select eligible respondents, who have accessed at least a PHC service in any of the PHCs in the State were included in the study, A semi-structured, interviewer-administered questionnaire was administered, and the data collected was analyzed using SPSS version 23.0. Appropriate statistical tests were used to examine the association between dependent and independent variables, while predictor variables that showed significant association with the outcome variables were further subjected to logistic regression analysis, to determine factors that affect clients’ satisfaction with PHC services. Statistical significance was determined at an alpha level set at 0.05 at a 95% confidence interval. Results Thirty-one percent of the respondents were satisfied with PHC services in Kaduna State with a mean composite satisfaction score of 3.78 ± 0.67. Age, ethnicity, level of education, and occupational status were factors affecting clients’ satisfaction with PHC services among the respondents. On multivariate analysis, age, ethnicity, educational status, and occupational status were significant factors affecting clients' satisfaction with PHC services. Clients of Hausa/Fulani extraction are one and a half times less likely to be satisfied with PHC services when compared to clients from other tribes aOR = 1.5, 95% CI (1.21–4.67); p = 0.003. In terms of educational status, clients with formal education are one and a one-third times more likely to be satisfied aOR = 1.3, 95% CI (0.17–0.94) with PHC service when compared with their counterparts with informal education ( p = 0.034). Conclusion Clients’ satisfaction with PHC services in Kaduna State, Northwest Nigeria was sub-optimal. Healthcare providers were recommended to improve their attitude bearing in mind clients’ peculiarities.
Melioidosis is a fatal emerging infectious disease of both man and animal caused by bacteria
. Variations were suggested to have existed among the different
clinical strains/genotypes which may ...implicate bacterial susceptibility and resistance toward antibiotics.
This study was designed to determine whether the phenotypic antibiotic resistance pattern of
is associated with the source of isolates and the genotype.
A collection of 111
isolates from veterinary cases of melioidosis and the environments (soil and water) were obtained from stock cultures of previous studies and were phylogenetically characterized by multilocus sequence typing (ST). The susceptibility to five antibiotics, namely meropenem (MEM), imipenem, ceftazidime (CAZ), cotrimoxazole (SXT), and co-amoxiclav (AMC), recommended in both acute and eradication phases of melioidosis treatment were tested using minimum inhibitory concentration antibiotics susceptibility test.
Majority of isolates were susceptible to all antibiotics tested while few resistant strains to MEM, SXT, CAZ, and AMC were observed. Statistically significant association was found between resistance to MEM and the veterinary clinical isolates (p<0.05). The likelihood of resistance to MEM was significantly higher among the novel ST 1130 isolates found in veterinary cases as compared to others.
The resistance to MEM and SXT appeared to be higher among veterinary isolates, and the novel ST 1130 was more likely to be resistant to MEM as compared to others.
This study was designed to determine the genotype and the phylogeny of Burkholderia pseudomallei isolated from veterinary cases and from the animal environments in Peninsular Malaysia. The Malaysian ...B. pseudomallei population were then compared to those found elsewhere. A total of 113 isolates from veterinary cases (35) and the environment (56 from soil and 22 from water) were characterized using multilocus sequence typing (MLST). Two novel alleles, allele 97 and 69 of the gene locus ace and lepA respectively were recovered. Isolates were resolved into 12 distinct sequence types (STs) out of which five were novel, namely ST1130, ST1131, ST1338, ST1339 and ST1367. The isolates from veterinary cases co-clustered with those from the environment. B. pseudomallei isolates in this study were highly clonal and have descended from a common ancestor clonal complex (CC) 48 found in Southeast Asia. This study shows that veterinary case isolates are often caused by similar STs, with similar populations found in the direct animal environment and those previously reported to cause human infections in Malaysia and elsewhere. Isolates of B. pseudomallei from human infections have been given more attention, with a comparatively lower focus on isolates from animals and the farm environment. This study highlighted the genotype and phylogeny of B. pseudomallei isolated from animals and the environment and their relations to the isolates from human cases reported in Malaysia and elsewhere. Most STs reported in this study, from veterinary cases and animal environment are similar to those previously reported as causing human infections in Malaysia and elsewhere. Therefore, even though direct zoonosis is uncommon, monitoring melioidosis occurrences in animals can provide insights on the bacterial strains infecting humans.
PurposeSupplier selection in the supply chain network (SCN) has strategic importance and involves multiple factors. The multi-criteria nature of the problem coupled with environmental uncertainty ...requires several procedures and considerations. The issue of decision-making in selecting the best among various qualified suppliers remains the major challenge in the pharmaceutical industry. This study investigated the multi-criteria multi-supplier decision-making process and proposed a model for supplier selection problems based on mixed-integer linear programming.Design/methodology/approachThe concept of principal component analysis (PCA) was used to reduce data dimensionality, and the four best criteria have been considered and selected. The result is subjected to decision-makers’ (DMs’) reliability test using the concept of a triangular fuzzy number (TFN). The importance of each supplier to each measure is established using fuzzy technique for order preference by similarity to an ideal solution approach, and the suppliers have ranked accordingly.FindingsThis study proposes a mixed integer linear programming model for supplier selection in a pharmaceutical company. The effectiveness of the proposed model has been demonstrated using a numerical example. The solution shows the model's applicability in making a sound decision in pharmaceutical companies in the space of reality. The model proposed is simple. Readily commercial packages such as LINDO/LINGO and GAMS can solve the model.Research limitations/implicationsThis research contributed to the systematic manner of supplier selection considering DMs’ value judgement under a fuzzy environment and is limited to the case study area. However, interested researchers can apply the study in other related manufacturing industries. However, the criteria have to be revisited to suit that system and might require varying ratings based on the experts' opinions in that field.Practical implicationsThis work suggests more insights practically by considering a realistic and precise investigation based on a real-life case study of pharmaceutical companies with six primary criteria and twenty-four sub-criteria. The study outcome will assist organizations and managers in conducting the best decision objectively by selecting the best suppliers with their various standards and terms among many available contenders in the manufacturing industry.Originality/valueIn this paper, the authors attempted to identify the most critical attributes to be preserved by the top managers (DMs) while selecting suppliers in pharmaceutical companies. The study proposed an MILP model for supplier selection in the pharmaceutical company using fuzzy TOPSIS.
Background: Adenotonsillitis, a common condition characterized by inflammation of the adenoids and tonsils, is caused by bacterial and fungal pathogens. Biofilm formation has been linked to disease ...chronicity and antibiotic resistance. However, the role of biofilms in adenotonsillitis remains poorly understood. This study aims to explore biofilms in adenotonsillitis biopsies, focusing on their characterization, frequency, and demographic distribution by determining the expression of polysaccharides in the biofilm matrix using Congo red stain, determining the presence and frequency of bacterial as well as fungal biofilms in adenotonsillar tissue, investigating any potential associations with disease severity, and evaluating the age and sex distribution of patients with adenotonsillitis.
Methods: This retrospective study analyzed formalin-fixed paraffin-embedded adenotonsillitis biopsies (n=50) collected from the university of Maiduguri teaching hospital. The expression of polysaccharides in the biofilm matrix was assessed using congo red stain. Bacterial and fungal biofilms were visualized using crystal violet and Gomori methenamine silver (GMS) stains, respectively. Data on patient demographics, diagnoses, and biofilm characteristics were analyzed.
Results: Adenoidtonsillitis was the most common diagnosis (82%), predominantly affecting children aged 0-9 years (76%). Gram's reaction was positive in 70% of cases, while Congo red staining indicated polysaccharide expression in 60%. GMS staining revealed fungal elements in 18% of cases.
Conclusions: This study sheds light on the characterization and frequency of bacterial and fungal biofilms in adenotonsillitis, emphasizing importance of biofilms in disease development and persistence. Understanding biofilm-associated infections can improve diagnostic and treatment strategies for adenotonsillitis in Nigeria and beyond
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