Bibliometric Analysis on Tuberculosis and Tuberculosis-Related Research Trends in Africa: A Decade-Long Study

Tuberculosis is one of the oldest known diseases and the leading communicable cause of deaths worldwide. Although several studies have been carried out on tuberculosis, no research has examined the publication trends in this area. Hence, this study aimed to fill the gap by conducting a bibliometric study in publications trends on tuberculosis and tuberculosis-related studies in Africa from 2010–2019 and explore the hotspots. Information in published documents on tuberculosis and its related studies from 2010 to 2019 were retrieved from the Web of Science (WoS) database. The bibliometric tool biblioshiny and Microsoft Excel 2016 were used to analyse the top leading journals, top cited documents, authors’ country production, country collaboration networks, most relevant authors, authors’ impacts, most relevant authors by corresponding author, most cited countries, university collaborations, most relevant affiliations, conceptual structural maps, title word co-occurrence networks, collaboration and significance of individual sources, university, country and keyword relations. A total of 3945 published documents were retrieved. The analyses showed that European Respiratory Journal was the leading journal in publications on tuberculosis studies with a total of 452 published articles, the WHO 2012 report was the most cited document with 2485 total citations while South Africa was the most productive country in tuberculosis publications as well as the leading country with the highest co-authorship collaboration. Analysis of top relevant authors revealed that Anonymous (133) and Dheda (44) were the two topmost relevant authors of tuberculosis publications, South Africa was the most relevant country by corresponding authors and the topmost cited country for tuberculosis publications. Furthermore, analysis of the university collaborations network showed that the University of Cape Town was the topmost university in Africa with the highest collaboration network, tuberculosis as a word had the highest co-occurrence network while the Three Field Plot diagram revealed the relations between universities, keywords and countries. This study provides a quantitative and qualitative analyses of the leading journals, most cited published articles, title word occurrences, and most relevant authors in published documents on tuberculosis and tuberculosis related studies from 2010–2019

Molecular Characterization and Antimicrobial Resistance Pattern of Escherichia coli Recovered from Wastewater Treatment Plants in Eastern Cape South Africa

Wastewater treatment plants (WWTPs) are designed to eliminate organic matter and pathogens but most WWTPs discharges antimicrobial resistance pathogens into aquatic milieu. The study aimed to examine the antibiotics resistant patterns and the presence of some resistance genes among E. coli isolates from WWTPs effluents. Water were collected from WWTPs final effluents, filtered through nitrocellulose membrane and the filter papers were placed on chromogenic agar plates, incubated for 24 h at 37 °C. Presumptive E. coli isolates (173) were obtained from the culture method. From the presumptive E. coli isolates screened by polymerase chain reaction (PCR), 111 isolates were positive and the positive isolates were further screened for six diarrheagenic E. coli pathotypes (EPEC, ETEC, EHEC, DAEC, EIEC, and EAEC) and from the pathotypes screened, nine isolates harboured daaE gene. The phenotypic susceptibility patterns of the 111 isolates to 12 antibiotics were determined by Kirby-Bauer disk diffusion technique. All the isolates were resistant to erythromycin and clindamycin. From the resistance genes screened, 31 isolates harboured mcr-1 gene and nine isolates harboured ermA gene. The study reveals that water samples recovered from the final effluents of WWTPs may likely be one of the major sources of antibiotic-resistant in Escherichia coli

Occurrence, Virulence and Antimicrobial Resistance-Associated Markers in Campylobacter Species Isolated from Retail Fresh Milk and Water Samples in Two District Municipalities in the Eastern Cape Province, South Africa

Campylobacter species are among the major bacteria implicated in human gastrointestinal infections and are majorly found in faeces of domestic animals, sewage discharges and agricultural runoff. These pathogens have been implicated in diseases outbreaks through consumption of contaminated milk and water in some parts of the globe and reports on this is very scanty in the Eastern Cape Province. Hence, this study evaluated the occurrence as well as virulence and antimicrobial-associated makers of Campylobacter species recovered from milk and water samples. A total of 56 water samples and 72 raw milk samples were collected and the samples were processed for enrichment in Bolton broth and incubated for 48 h in 10% CO2 at 42 °C under microaerobic condition. Thereafter, the enriched cultures were further processed and purified. After which, presumptive Campylobacter colonies were isolated and later confirmed by PCR using specific primers for the detection of the genus Campylobacter, target species and virulence associated genes. Antimicrobial resistance profiles of the isolates were determined by disk diffusion method against a panel of 12 antibiotics and relevant genotypic resistance genes were assessed by PCR assay. A total of 438 presumptive Campylobacter isolates were obtained; from which, 162 were identified as belonging to the genus Campylobacter of which 36.92% were obtained from water samples and 37.11% from milk samples. The 162 confirmed isolates were further delineated into four species, of which, 7.41%, 27.16% and 8.64% were identified as C. fetus, C. jejuni and C. coli respectively. Among the virulence genes screened for, the iam (32.88%) was most prevalent, followed by flgR (26.87%) gene and cdtB and cadF (5.71% each) genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (95.68%), while the lowest was observed against imipenem (21.47%). Other high phenotypic resistance displayed by the isolates were against erythromycin (95.06%), followed by ceftriaxone (93.21%), doxycycline (87.65%), azithromycin and ampicillin (87.04% each), tetracycline (83.33%), chloramphenicol (78.27%), ciprofloxacin (77.78%), levofloxacin (59.88%) and gentamicin (56.17%). Relevant resistance genes were assessed in the isolates that showed high phenotypic resistance, and the highest resistance gene harbored by the isolates was catII (95%) gene while VIM, KPC, Ges, bla-OXA-48-like, tetC, tetD, tetK, IMI and catI genes were not detected. The occurrence of this pathogen and the detection of virulence and antimicrobial resistance-associated genes in Campylobacter isolates recovered from milk/water samples position them a risk to human health

Campylobacteriosis Agents in Meat Carcasses Collected from Two District Municipalities in the Eastern Cape Province, South Africa

Raw meats are sometimes contaminated with Campylobacter species from animal faeces, and meats have repeatedly been implicated in foodborne infections. This study evaluated the prevalence, virulence genes, antimicrobial susceptibility patterns, and resistance gene determinants in Campylobacter species isolated from retailed meat carcasses. A total of 248 raw meat samples were collected from butcheries, supermarkets, and open markets; processed for enrichment in Bolton broth; and incubated at 42 °C for 48 h in 10% CO2. Thereafter, the broths were streaked on modified charcoal cefoperazone deoxycholate agar (mCCDA) plates and incubated at the same conditions and for the same amount of time. After incubation, colonies were isolated and confirmed by Polymerase chain reaction using specific oligonucleotide sequences used for the identification of the genus Campylobacter, species, and their virulence markers. The patterns of antimicrobial resistance profiles of the identified isolates were studied by disk diffusion method against 12 antibiotics, and relevant resistance genes were assessed by PCR. From culture, 845 presumptive Campylobacter isolates were obtained, of which 240 (28.4%) were identified as genus Campylobacter. These were then characterised into four species, of which C. coli had the highest prevalence rate (22.08%), followed by C. jejuni (16.66%) and C. fetus (3.73%). The virulence genes detected included iam (43.14%), cadF (37.25%), cdtB (23.53%), flgR (18.63%), and flaA (1.96%), and some of the isolates co-harboured two to four virulence genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (100%), and the lowest level of resistance was observed against imipenem (23.33%). The frequency of resistance genes detected included catll (91.78%), tetA (68.82%), gyra (61.76%), ampC (55%), aac(3)-IIa (aacC2)a (40.98%), tetM (38.71%), ermB (18.29%), tetB (12.90%), and tetK (2.15%). There is a high incidence of Campylobacter species in meat carcasses, suggesting these to be a reservoir of campylobacteriosis agents in this community, and as such, consumption of undercooked meats in this community is a potential health risk to consumers

Molecular determination of genetic diversity among Campylobacter jejuni and Campylobacter coli isolated from milk, water, and meat samples using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR)

Consumption of contaminated meat, milk, and water are among the major routes of human campylobacteriosis. This study aimed to determined the genetic diversity of C. coli and C. jejuni isolated from meat, milk, and water samples collected from different locations. From the 376 samples (meat = 248, cow milk = 72, and water = 56) collected, a total of 1238 presumptive Campylobacter isolates were recovered and the presence of the genus Campylobacter were detected in 402 isolates, and from which, 85 and 67 isolates were identified asC. jejuni and C. coli respectively. Of which, 71 isolates identified as C. coli (n = 35) and C. jejuni (n = 36) were randomly selected from meat, milk, and water samples and were genotyped using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). The digital images of the ERIC-PCR genotype were analyzed by GelJ v.2.0 software. The diversity and similarity of the isolates were assessed via an unweighted-pair group method using average linkages clustering algorithm. The results showed that the 36 C. jejuni strains separated into 29 ERIC-genotypes and 4 clusters while the 35 C. coli were delineated into 29 ERIC-genotypes and 6 clusters. The study revealed the genetic diversity among C. coli and C. jejuni strains recovered from different matrices characterized by Gelj

Molecular Characterization and Antimicrobial Resistance Pattern of Escherichia coli Recovered from Wastewater Treatment Plants in Eastern Cape South Africa

Wastewater treatment plants (WWTPs) are designed to eliminate organic matter and pathogens but most WWTPs discharges antimicrobial resistance pathogens into aquatic milieu. The study aimed to examine the antibiotics resistant patterns and the presence of some resistance genes among E. coli isolates from WWTPs effluents. Water were collected from WWTPs final effluents, filtered through nitrocellulose membrane and the filter papers were placed on chromogenic agar plates, incubated for 24 h at 37 °C. Presumptive E. coli isolates (173) were obtained from the culture method. From the presumptive E. coli isolates screened by polymerase chain reaction (PCR), 111 isolates were positive and the positive isolates were further screened for six diarrheagenic E. coli pathotypes (EPEC, ETEC, EHEC, DAEC, EIEC, and EAEC) and from the pathotypes screened, nine isolates harboured daaE gene. The phenotypic susceptibility patterns of the 111 isolates to 12 antibiotics were determined by Kirby-Bauer disk diffusion technique. All the isolates were resistant to erythromycin and clindamycin. From the resistance genes screened, 31 isolates harboured mcr-1 gene and nine isolates harboured ermA gene. The study reveals that water samples recovered from the final effluents of WWTPs may likely be one of the major sources of antibiotic-resistant in Escherichia coli

Global Systematic Mapping of Road Dust Research from 1906 to 2020: Research Gaps and Future Direction

Roadside dust resulting from industrialization of society has an adverse effect on the environment and human health. However, despite the global research progress in this field, to date, no bibliometric report on the subject has been documented. Hence, bibliometric mapping is important to assess the quality and quantity of the global research activities on road dust. Data were retrieved from the Web of Science Core Collection and Scopus, while RStudio software was used for data analysis. A total of 1186 publications were retrieved from these databases, and progressive growth in the subject over the last 10 years was observed, considering the positive correlation (y = 0.0024 × 3 − 0.1454 × 2 + 2.6061 × −8.5371; R2 = 0.961) obtained for these indices. China had the highest publications, and environmental science-related journals dominated publications on road dust. The findings suggest that other regions of the world, such as the Middle East and Africa, need to channel their research efforts toward this field, considering the shortage of publications on the subject from these regions. Therefore, this study shows that assessing research activity on road dust is important for planning impactful research directions and setting protective and adaptive policies related to the field

Chemical constituents, antibacterial and antioxidant properties of the essential oil flower of Tagetes minuta grown in Cala community Eastern Cape, South Africa

Abstract Background Tagetes minuta has a long record of human use for the treatment of stomach and intestinal diseases. Most drugs used for diseases treatment are less efficacious with side effects and this brought the search for new treatment regimens mainly from medicinal plants. Method The essential oil (EO) was extracted by Clevenger’s-type apparatus and its chemical composition, antioxidant and antibacterial properties were determined by GC-MS, spectrophotometric and broth dilution methods respectively. S. uberis, E. cloacae, S. aureus, M. smegmatis, L. ivanovii, Vibrio spp. and E. coli bacteria strains were used as test bacteria. Results GC-MS analysis revealed 98 compounds in the EO flower of T. minuta and β-Ocimene (14. 40%) was the major chemical constituents. The EO exhibited highest inhibitory effect against DPPH radical, followed by its effect on ABTS, while LP radical showed the least sensitivity with IC50 values of 2.45 mg/mL, 2.76 mg/mL and 3.23 mg/mL respectively. The EO showed antibacterial activities against all test organisms with MIC value for S. aureus, M. smegatis and S. uberis at 0.125 mg/mL and for L. ivanovii, Vibrio spp., E. cloacae and E. coli at 0.06 mg/mL. The EO showed MBC against E. cloacae and E. coli at 0.06 mg/mL at 0.5 mg/mL for S. uberis and 0.125 mg/mL for Vibrio spp. Conclusion Findings from this study suggest that the EO of T. minuta flower may be a useful candidate in the search for lead constituents for the synthesis of new potent antibacterial and antioxidant agent