Rapid detection of microbial contamination in Ghanaian herbal medicines by PCR analysis

Microbial Contamination of Herbal Preparations on the Ghanaian Market, Accra

In developing countries, an estimated 80% of the population use traditional herbal medicines as part of their primary health care. As the market for herbal medicine expands in many African countries, partly due to their use in the treatment of COVID-19, there is the need to address all the associated safety issues. The aim of the study was to evaluate the microbial contamination of locally prepared, as well as imported foreign herbal products sold in Accra. Standard microbiological methods were employed in the enumeration of coliforms and the identification of pathogenic microbes in 60 herbal preparations that were sampled. A larger proportion (76.7%) of local herbal preparations was contaminated with bacteria as compared with imported ones (63.3%). Bacillus species and Pseudomonas aeruginosa were the predominant bacteria obtained from foreign and locally manufactured herbal preparations, respectively. A proportion of 36.7% (11) of the local samples were positive for coliform and the coliform counts ranged from 3.0 × 10¹ cfu/ml to 2.0 × 10⁴ cfu/ml. Two foreign herbal samples (6.7%) were positive for coliforms; one had a count of 1.7 × 10⁵ cfu/g while the other had 2 × 10⁴ cfu/g. Herbal preparations sold in markets of Accra harbour several microbial pathogens; the risk is relatively higher for locally produced herbal preparations compared to imported herbal preparations. As a result, it is recommended that quality assurance in the production of local herbal preparations should be thoroughly monitored from the beginning of production to the final selling of the preparations. There is also the need to strengthen microbiological safety monitoring of imported herbal preparations.

Quality assessment of African herbal medicine: A systematic review and the way forward

BACKGROUND

In Africa, herbalism supplements allopathic medicine's efforts to ensure Universal Health Coverage attainment. This review was conducted to identify and to summarise current literature on methodological approaches used for quality control of herbal medicines in Africa, to evaluate the gaps associated with existing strategies within context of best practices, and make recommendations for future improvements.

METHODS

A systematic search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were screened and assessed for eligibility.

RESULTS

118 articles were included into the study. There was a high preference for impurity profiling tests (77%) indicating the prioritization for tests that guarantee safety despite the limited analytical resources available. Other classes of tests reported included identification tests (29%), physicochemical tests (18%), and content assays (12%). Although standard methods exist in preparing samples for impurity tests, different techniques were observed in different studies, and this could lead to differences in analytical outcomes. Content assays focused on single marker assessments, which may be inadequate to comprehensively assess the quality of products.

CONCLUSION

This review provides knowledge of existing strengths and challenges for herbal medicine quality assessments in Africa. For future it is recommended to implement more studies on contaminants (e.g. mycotoxins) and pharmaceutical adulterants. The use of chemometrics to develop analytical methods should be promoted. Also, stakeholders in the medicine quality industry in Africa need to effectively collaborate to establish a well co-ordinated and harmonized system to provide a sustainable framework for the GACP and GMP guided production and quality assurance of herbal medicines.

Removal of Polymerase Chain Reaction Inhibitors by Electromembrane Extraction

Polymerase chain reaction (PCR) technology has become the cornerstone of DNA analysis. However, special samples (e.g., forensic samples, soil, food, and mineral medicine) may contain powerful PCR inhibitors. High levels of inhibitors can hardly be sufficiently removed by conventional DNA extraction approaches and may result in the complete failure of PCR. In this work, the removal of PCR inhibitors by electromembrane extraction (EME) was investigated for the first time. To demonstrate the universality of the approach, EME formats with and without supported membranes (termed parallel-EME and μ-EME, respectively) were employed, and both anionic [humic acid (HA)] and cationic (Ca²⁺) PCR inhibitors were used as models. During EME, charged inhibitors in the sample migrate into the liquid membrane in the presence of an electric field and might further leech into the waste solution, while PCR analytes remain in the sample. After EME, the clearance values for HA at 0.2 and 2.5 mg mL^-1 were 94 and 85%, respectively, and that for Ca²⁺ (275 mM) was 63%. Forensic PCR-short tandem repeat (PCR-STR) genotyping showed that EME significantly reduced the interference by HA in PCR-STR analysis and displayed a higher HA purge capability compared to existing methods. Furthermore, by combining EME with liquid-liquid extraction or solid-phase extraction, satisfactory STR profiles were obtained from HA-rich blood samples. In addition, false-negative reports of bacterial detection in mineral medicine and shrimps were avoided after the removal of Ca²⁺ by μ-EME. Our research demonstrates the great potential of EME for the purification of DNA samples containing high-level PCR inhibitors and opens up a new application direction for EME.

Baicalin inhibits Escherichia coli isolates in bovine mastitic milk and reduces antimicrobial resistance

In this study, we aimed to evaluate the inhibitory effect of baicalin on Escherichia coli in vitro and the effects of baicalin treatment on antimicrobial resistance of the E. coli isolates. Through isolation, purification, and identification, a total of 56 E. coli strains were isolated from 341 mastitic milk samples. The study of inhibition effect of baicalin on the E. coli strains in vitro was focused on permeability and morphology of the isolates using an alkaline phosphatase kit and scanning electron microscopy. Furthermore, the resistance spectrum of the isolates to the common antimicrobial agents was tested at sub-minimum inhibitory concentrations of baicalin by the agar dilution method. Extended-spectrum β-lactamase and plasmid-mediated quinolone resistance genes were amplified by PCR before and after incubation with baicalin. The results revealed that baicalin has certain inhibitory effects on the isolates in vitro. The alkaline phosphatase enzyme activity was significantly increased from 1.246 to 2.377 U/100 mL, and the surface of E. coli was concave and shriveled. Analysis of the resistance spectrum and PCR amplification showed that, after administration with baicalin, the sensitivity of most strains to the selected antimicrobial agents was enhanced. Strikingly, the drug-resistant genes from 71.43% (40/56) of these isolates were found to have drug-resistant genes to different extents. Altogether, the current study confirmed both the inhibitory effect on Escherichia coli in vitro and the reduction of antimicrobial resistance by baicalin. This is the first comprehensive study to report on baicalin, a traditional Chinese medicine that acts on E. coli isolated from the mastitic milk samples.

Prevalence of Antibiotic-Resistant Escherichia coli in Drinking Water Sources in Hangzhou City

This study investigated the distribution of antibiotic resistant Escherichia coli (E. coli) and examined the possible relationship between water quality parameters and antibiotic resistance from two different drinking water sources (the Qiantang River and the Dongtiao Stream) in Hangzhou city of China. E. coli isolates were tested for their susceptibility to 18 antibiotics. Most of the isolates were resistant to tetracycline (TE), followed by ampicillin (AM), piperacillin (PIP), trimethoprim/sulfamethoxazole (SXT), and chloramphenicol (C). The antibiotic resistance rate of E. coli isolates from two water sources was similar; For E. coli isolates from the Qiantang River, their antibiotic resistance rates decreased from up- to downstream. Seasonally, the dry and wet season had little impact on antibiotic resistance. Spearman's rank correlation revealed significant correlation between resistance to TE and phenicols or ciprofloxacin (CIP), as well as quinolones (ciprofloxacin and levofloxacin) and cephalosporins or gentamicin (GM). Pearson's chi-square tests found certain water parameters such as nutrient concentration were strongly associated with resistance to some of the antibiotics. In addition, tet genes were detected from all 82 TE-resistant E. coli isolates, and most of the isolates (81.87%) contained multiple tet genes, which displayed 14 different combinations. Collectively, this study provided baseline data on antibiotic resistance of drinking water sources in Hangzhou city, which indicates drinking water sources could be the reservoir of antibiotic resistance, potentially presenting a public health risk.

Identification of bacterial contaminants in polyherbal medicines used for the treatment of tuberculosis in Amatole District of the Eastern Cape Province, South Africa, using rapid 16S rRNA technique

BACKGROUND

Polyherbal medicines are used for the treatment of many diseases in many African and Asian communities. With the increasing use of these remedies, several investigations have shown that they are associated with a broad variety of residues and contaminants. This study investigates the presence of bacteria in the polyherbal medicines used for the treatment of tuberculosis (TB) in the Eastern Cape Province of South Africa.

METHODS

Bacterial DNA was extracted from the polyherbal medicines, and a fragment of the bacterial 16S rRNA gene was amplified by PCR with universal primers 27F and 518R. The amplicons were visualised on agarose gel electrophoresis, followed by end repair and adaptor ligation. They were further purified and quantified using Library Preparation kit NEBNext® UltraT DNA Library Prep Kit for Illumina, and the amplicons were run on illumina's MiSeq platform.

RESULTS

Different bacterial species were identified in all each of the polyherbal medicines. Generally, the most prominent and common bacteria recovered from all the samples were Bacillus sp., Enterobacter sp., Klebsiella sp., Rahnella sp., Paenibacillus sp., Clostridium sp. and Pantoea sp. Others are Pseudomonas sp., Raoultella ornithinolytica, Salmonella enterica and Eubacterium moniliforme.

CONCLUSIONS

This study, thus, revealed the presence of pathogenic and non-pathogenic bacteria in the polyherbal medicines used for the treatment of tuberculosis in the study area. The implications of the findings are discussed in relation to the health care of the patients of tuberculosis in the study area, having in mind that they are immunocompromised individuals.