Linda A Bester

Linda A Bester
University of KwaZulu-Natal | ukzn · Biomedical Resource Unit

PhD
Food-related bacteria dissemination, epidemiology, molecular surveillance, zoonotic pathogens, human health risk.

About

72
Publications
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Introduction
Linda A Bester currently works at the Biomedical Resource Unit, University of KwaZulu-Natal. Research themes include zoonotic bacteria via the food chain, antibiotic resistance, human health risks, molecular surveillance studies, bioinformatics, Salmonella, Enterococcus, Campylobacter, Staphylococcus, Bacillus, Klebsiella and E. coli is of interest.

Publications

Publications (72)
Article
Full-text available
Salmonella enterica is a zoonotic pathogen of worldwide public health importance. We characterised Salmonella isolates from poultry along the farm-to-fork continuum using whole genome sequencing (WGS) and bio-informatic analyses. Three multilocus sequence types (MLSTs), i.e., ST15 (1.9%), ST152 (5.9%) and ST1316 (92.2%) and three serotypes, i.e., S...
Presentation
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Centuries ago, scientists noticed resemblances in disease progression between animals and humans. The modus operandi up until that moment had been to practice medicine on animals separately from humans as if these were confined microbiological spaces, and the acknowledgement of antibiotic resistance in microorganisms set in motion a global movement...
Article
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Poultry is a cheap source of animal protein and constituent of diets in Africa. Poultry can serve as a reservoir for Salmonella and cause food-borne infections in humans. This review describes Salmonella contamination of food, poultry and the farming environment, antimicrobial resistance (AMR) profiles and serotypes of Salmonella, as well as the fa...
Article
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Background: Diarrheagenic E. coli (DEC) strains are a major cause of diarrheal diseases in both developed and developing countries. Healthy asymptomatic animals may be reservoirs of zoonotic DEC, which may enter the food chain via the weak points in hygiene practices. Aim: We investigated the prevalence of DEC along the pig production continuum fro...
Article
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The presence of the zoonotic pathogen Salmonella in the food supply chain poses a serious public health threat. This study describes the prevalence, susceptibility profiles, virulence patterns, and clonality of Salmonella from a poultry flock monitored over six weeks, using the farm-to-fork approach. Salmonella was isolated using selective media an...
Article
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The hospital environment acts as a reservoir in the transmission of pathogens, such as MRSA, which may cause hospital-acquired infections. This study aimed to ascertain the prevalence, genetic relatedness, antibiotic resistance, and virulence profile of MRSA on some frequently touched hospital sites in South Africa. A total of 777 swabs were random...
Article
Aims: Enterococci are implicated in hospital-acquired infections and show high tenacity on inanimate objects in the hospital environment. This study investigated the prevalence of Enterococcus spp. in selected wards in public hospitals at four levels of healthcare from a district in KwaZulu-Natal, South Africa. Methods and results: Swabs were co...
Article
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Microbial infections are a major public health concern. Antimicrobial peptides (AMPs) have been demonstrated to be a plausible alternative to the current arsenal of drugs that has become inefficient due to multidrug resistance. Herein we describe a new AMP family, namely the super-cationic peptide dendrimers (SCPDs). Although all members of the ser...
Article
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This study aimed to assess the molecular dissemination of Bacillus species in public hospitals in South Africa. The study conducted over three months during 2017 involved representative samples obtained from three wards (general ward, Intensive care unit (ICU) and paediatric unit) from four public hospitals denoted as A (Central), B (Tertiary), C (...
Article
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Staphylococcus epidermidis has become an important nosocomial pathogen. Multidrug resistance makes S. epidermidis infections difficult to treat. The study aims to describe the genomic characteristics of methicillin-resistant S. epidermidis (MRSE) isolated from clinical sources, to comprehend the genetic basis of antibiotic resistance, virulence, an...
Article
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Bacteria that cause life-threatening illnesses in humans are also capable of contaminating hospital surfaces, thus pose as a potential source of infection. This study aimed to investigate the prevalence, genetic diversity, virulence, and antibiotic resistance profile of Klebsiella pneumoniae in South Africa. In a nonoutbreak setting involving four...
Article
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Campylobacter spp. are among the leading foodborne pathogens, causing campylobacteriosis, a zoonotic infection that results in bacterial gastroenteritis and diarrheal disease in animals and humans. This study investigated the molecular epidemiology of antibiotic-resistant Campylobacter spp. isolated across the farm-to-fork-continuum in an intensive...
Article
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Foodborne pathogens, including antibiotic-resistant species, constitute a severe menace to food safety globally, especially food animals. Identifying points of concern that need immediate mitigation measures to prevent these bacteria from reaching households requires a broad understanding of these pathogens’ spread along the food production chain....
Article
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Although Staphylococcus aureus is a major threat to the veterinary, agricultural, and public health sectors because of its zoonotic potential, studies on its molecular characterisation in intensive animal production are rare. We phenotypically and genotypically characterised antibiotic-resistant S. aureus in intensive pig production in South Africa...
Article
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Coagulase-negative staphylococci (CoNS) are increasingly associated with nosocomial infections, especially among the immunocompromised and those with invasive medical devices, posing a significant concern. We report on clinical multidrug-resistant CoNS from the uMgungundlovu District, KwaZulu-Natal Province, South Africa, as emerging pathogens. One...
Article
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Antibiotic resistance profiles of Escherichia coli were investigated in an intensive pig production system in the uMgungundlovu District, South Africa, using the ‘farm-to-fork’ approach. Four hundred seventeen (417) samples were collected from pig and pig products at different points (farm, transport, and abattoir). E. coli was isolated and enumera...
Article
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The increased use of antibiotics in food animals has resulted in the selection of drug-resistant bacteria across the farm-to-fork continuum. This study aimed to investigate the molecular epidemiology of antibiotic-resistant Escherichia coli from intensively produced poultry in the uMgungundlovu District, KwaZulu-Natal, South Africa. Samples were co...
Article
With the introduction of the One Health approach to global health advocated by the World Health Organization, the role of the environment as a reservoir and transmission route for diverse microorganisms is increasingly being recognised globally. This study investigated the diversity and functional profiles of bacterial communities using high-throug...
Article
Aim To investigate the dissemination of Salmonella spp. within four levels of government hospital in KwaZulu-Natal, South Africa. Methods Salmonella identification was performed by amplification of the invA gene. Isolates were subjected to antimicrobial susceptibility testing and molecular characterisation of eight resistance genes and three virul...
Article
Full-text available
Coagulase-negative staphylococci (CoNS) have engendered substantial interest in recent years as pathogenic causes of infections in both human and veterinary medicine, especially in the immunocompromised, critically ill, long-term hospitalised and in those harbouring invasive medical devices such as catheters. They have been implicated in infections...
Article
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The white shark (Carcharodon carcharias) is responsible for 49% of shark-related injuries in South Africa, yet no information currently exists on the composition or antibiotic resistance of bacteria hosted by these apex predators in South African waters. This study aimed to address this gap by sampling the bacteria present in the oral cavities of 2...
Chapter
Recent progress in the sequencing technologies and other omics approaches have had a profound impact on microbiology and helped to develop a more complete picture of the microbial composition and function of different ecosystems. One of the observations from meta-omics research is some microbes are ubiquitous in diverse ecosystems and that such sha...
Article
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The study undertook genome mining and comparative genomics to gain genetic insights into the dominance of the methicillin-resistant Staphylococcus aureus (MRSA) endemic clone ST612-CC8-t1257-SCCmec_IVd(2B), obtained from the poultry food chain in South Africa. Functional annotation of the genome revealed a vast array of similar central metabolic, c...
Article
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Background: This study determined the prevalence and antibiotic susceptibility profiles of Staphylococcus aureus isolated from selected critical control points (farm, transport, abattoir, and retail product) in an intensive poultry production system in the uMgungundlovu District, South Africa, using the "farm to fork" approach. Materials and Metho...
Article
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This study investigated the antibiotic resistance, virulence profiles, and clonality of Campylobacter jejuni and Campylobacter coli isolated from an intensive poultry farming system in KwaZulu-Natal, South Africa. Following ethical approval, samples were collected over six weeks using the farm-to-fork approach. Campylobacter spp. were identified us...
Article
The poultry industry is among the main protein suppliers worldwide. Thus, this study determined the antibiotic resistance and virulence profiles of Enterococcus spp. along the farm-to-fork production chain of an intensive poultry system in the uMgungundlovu District, Kwazulu-Natal, South Africa. Overall, 162 samples along the continuum (growth phas...
Article
Full-text available
Herein, we highlight the genome sequence of a novel Enterococcus faecalis sequence type 922 (ST922) strain isolated in South Africa. The 3,564,442-bp genome harbored defense systems, a resistome, a virulome, and genetic support, which is of importance to the control of hospital-acquired infections. The genomics of Enterococcus faecalis yields great...
Article
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Here, we describe the genomic sequence of a drug-resistant Staphylococcus aureus sequence type 239 (ST239) strain, SA9, isolated from a slaughterhouse chicken carcass in South Africa, including information about its antibiotic resistome, virulome, efflux genes, clonal lineage, and mobilome. This genomic information offers vital insights for the con...
Article
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Background: Methicillin-resistant Staphylococcus aureus (MRSA) are a major cause of hospital-and community-acquired infection. They can colonize humans and cause a wide range of infections including pneumonia, endocarditis and bacteraemia. We investigated the molecular mechanism of resistance and virulence of MRSA isolates from a teaching hospital...
Article
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To elucidate the molecular determinants of tetracycline resistance in clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates from the private health sector in KwaZulu-Natal province (KZN), South Africa (SA). Seventy-five clinical MRSA isolates were collected from the private hospital sector in KZN, SA over a one-year period. Susceptib...
Article
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Extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) represent a significant public health concern globally and are recognized by the World Health Organization as pathogens of critical priority. However, the prevalence of ESBL-PE in food animals and humans across the farm-to-plate continuum is yet to be elucidated in Sub-Saharan cou...
Article
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Carbapenem-resistant Enterobacteriaceae (CRE)-mediated infections remain a huge public health concern. CRE produce enzymes such as metallo-β-lactamases (MBLs), which inactivate β-lactam antibiotics. Hence, developing efficient molecules capable of inhibiting these enzymes remain a way forward to overcoming this phenomenon. In this study, we demonst...
Article
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Aims: We hypothesised and confirmed that tannic acid (TA) reverses carbapenem resistance by inhibiting carbapenemases in class A and B carbapenemase-producing Enterobacteriaceae. Methods and Results: MICs of carbapenems in the presence and absence of TA and other efflux pump inhibitors, TA-carbapenemases inhibition assays and computational studies...
Article
Full-text available
Carbapenem-resistant Enterobacteriaceae (CRE)-mediated infections remain a significant public health concern and have been reported to be critical in the World Health Organization’s priority pathogens list for the research and development of new antibiotics. CRE produce enzymes, such as metallo-β-lactamases (MBLs), which inactivate β-lactam antibio...
Conference Paper
Background and objectives: Extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) represent a significant public health concern globally and are recognized by the World Health Organization as pathogens of critical priority in research. However, the prevalence of ESBL-PE in food animals and humans across the farm-to-plate continuum...
Preprint
Full-text available
Resistance to antibiotics is increasing worldwide, necessitating urgent action to sustain the efficacy of existing antibiotics in clinical use. We show that tannic acid (TA) in combination with carbapenems can reduce and/or reverse the minimum inhibitory concentrations (MICs) of carbapenems to susceptible values in Enterobacteriaceae that express c...
Preprint
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Metallo-β-lactamase producing Enterobacteriaceae are of grave clinical concern particularly as there are no Metallo-β-lactamase (MBL) inhibitors approved for clinical use. The discovery and development of MBL inhibitors to restore the efficacy of available β-lactams are thus imperative. We investigated a zinc-chelating moiety, 1, 4, 7-triazacyclono...
Article
Full-text available
The worldwide proliferation of life-threatening metallo-β-lactamase (MBLs)-producing Gram-negative bacteria is a serious concern to public health. MBLs are compromising the therapeutic efficacies of β-lactams, particularly carbapenems, which are last-resort antibiotics indicated for various multidrug-resistant bacterial infections. Inhibiting enzym...
Article
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Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) are included on the WHO high priority list of pathogens that require urgent intervention. Hence emphasis needs to be placed on developing novel class of molecules to tackle these pathogens. Teixobactin is a new class of antibiotic that has demonstrated an...
Article
The anti-leprosy drug clofazimine was recently repurposed as part of a newly endorsed short-course regimen for multidrug-resistant tuberculosis. It also enables significant treatment-shortening when added to the first-line regimen for drug-susceptible tuberculosis in a mouse model. However, clofazimine causes dose- and duration-dependent skin disco...
Article
An acid cleavable lipid (SA-3 M) was synthesized and used to develop pH-responsive solid lipid nanoparticles (SLNs) to deliver vancomycin base (VM-FB) to acidic infection sites. The size, polydispersity index and zeta potential of VM-FB_SA-3 M_SLNs were 132.9 ± 9.1 nm, 0.159 ± 0.01 and −26 ± 4.4 mV respectively, with 57.80 ± 1.1% encapsulation effi...
Article
Full-text available
Introduction: There is a dearth of surveillance data on clinical Campylobacter in South Africa, particularly in the private healthcare environment. We investigated the prevalence of resistance to first-line antibiotics used to treat campylobacterioses in clinical Campylobacter isolates from a private pathology laboratory. Methodology: Identifica...
Article
Objectives The anti-leprosy drug clofazimine has been shown to have antimicrobial activity against Mycobacterium tuberculosis and has been associated with treatment-shortening activity in both clinical and preclinical studies of TB chemotherapy. However, a reported lack of early bactericidal activity (EBA) in TB patients has raised questions regard...
Article
Full-text available
A study was undertaken to determine the neuroprotective potential of Linezolid (LIN) in an animal model. Female Sprague–Dawley rats were either given a single (100 mg/kg) dose or treated daily for 4 weeks. A validated LC–MS/MS method was used to measure LIN levels in plasma and brain, this was paired with mass spectrometry imaging to determine the...
Article
Full-text available
This study compared phenotypic and genotypic identification methods of Campylobacter spp. against the polymerase chain reaction (PCR) in terms of sensitivity, specificity, positive-predictive value and negative-predictive value. Thermophilic Campylobacter isolates were identified using conventional biochemical tests, specifically hippurate hydrolys...
Article
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Given the recent explosion of mass spectrometric imaging (MSI), it has become easier to assess drug tissue localisation without the use of radiolabeling and other more complex methods (such as PET and MRI). For MSI tissue preparation is of utmost importance, however, the lung in particular does pose some difficulties with imaging since it is made u...
Article
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A literature review was undertaken to ascertain the molecular basis for tigecycline and colistin resistance mechanisms and the experimental basis for the detection and delineation of this resistance particularly in carbapenemase-producing Gram-negative bacteria. Pubmed, Google Scholar and Science Direct were searched with the keywords colistin, tig...
Article
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Objectives: Due to the lack of information on the plasmid content of MRSA strains in South Africa (SA), this study investigated the resistance and virulence mechanisms of 27 clinical isolates from the private health care sector over a period of 3 months. Methods: Plasmids were extracted and the presence of MRSA confirmed by the presence of mecA....
Article
Experimental and clinical studies have indicated that the anti-leprosy drug clofazimine may contribute treatment-shortening activity when included in tuberculosis treatment regimens. Clofazimine accumulates to high levels in the tissues, has a long half-life, and remains in the body for months after stopping administration. We hypothesized that, in...
Article
Aims: This study aimed at investigating the use of metal chelators as potential metallo-β-lactamase inhibitors (MBL). Methods and results: The minimum-inhibitory concentration (MIC) of meropenem was ascertained alone and in combination with various concentrations of macrocyclic (1,4,7- triazacyclononane-1-glutaric acid-4,7-diacetic acid = NODAGA...
Article
Fluoroquinolones are broad-spectrum antibiotics with efficacy against a wide range of pathogenic microbes associated with respiratory and meningeal infections. The potential toxicity of this class of chemical agents is a source of major concern and is becoming a global issue. The aim of this study was to develop a method for the brain distribution...
Article
Tigecycline (TIG), a derivative of minocycline, is the first in the novel class of glycylcyclines and is currently indicated for the treatment of complicated skin structure and intra-abdominal infections. A selective, accurate and reversed-phase high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for th...
Article
1. The penetration of tetracyclines into the brain has been widely documented. The aim of this work was to develop a matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI MSI) method for the molecular histology of doxycycline (DOX) in the healthy rat brain. 2. The time-dependent distribution was investigated after an i.p. dos...