Antimicrobial-resistant Strains Research Articles

Review on anti-microbial resistance patterns of staphylococcus aureus isolated from mastitic cow’s milk: Ethiopian context

Aim of this paper is to review antimicrobial resistance profile of Staphylococcus aureus (S. aureus) isolated from mastitic cow milk in Ethiopia between 2013- 2023. S. aureus causes chronic intramammary infections, causing financial losses and challenging antimicrobial therapy globally. In Ethiopia meta-analysis of the pooled prevalence of bovine mastitis was 47.6% showing S. aureus as the major isolates accounting for 13.4% and 16.5% of clinical and subclinical mastitis. In Ethiopia, there are indication of the misuse of antibiotics coupled with the rapid spread of resistant bacterial nature and inadequate surveillance, which contributed to the problem. According to this review resistance profile of S. aureus studied in Ethiopia, the bulk of tested isolates showed alarmingly high levels of resistance to widely used antimicrobial drugs for the treatment of mastitis, particularly penicillin G and tetracycline. Variuos studies warned low susceptibility of S. aureus to commonly used antimicrobials such as penicillin G and tetracycline as a great concern because this antibiotic represents the main antibiotic group recommended for staphylococcal mastitis infection in Ethiopia. If essential steps to stop the indiscriminate use of antibiotics are not implemented, the prevalence of antibiotic-resistant S. aureus could rise posing major risks to both animal and human health. Therefore, conducting regular antimicrobial sensitivity testing before treatment helps select effective antibiotics which reduce the development of resistance to commonly used antibiotics. Further studies should be conducted to detect antimicrobial resistant strains, continiuos surveillance and monitoring of S. aureus to prevent the spread of milk-borne drug-resistant strains throughout communities.

AMRomics: a scalable workflow to analyze large microbial genome collections

Whole genome analysis for microbial genomics is critical to studying and monitoring antimicrobial resistance strains. The exponential growth of microbial sequencing data necessitates a fast and scalable computational pipeline to generate the desired outputs in a timely and cost-effective manner. Recent methods have been implemented to integrate individual genomes into large collections of specific bacterial populations and are widely employed for systematic genomic surveillance. However, they do not scale well when the population expands and turnaround time remains the main issue for this type of analysis. Here, we introduce AMRomics, an optimized microbial genomics pipeline that can work efficiently with big datasets. We use different bacterial data collections to compare AMRomics against competitive tools and show that our pipeline can generate similar results of interest but with better performance. The software is open source and is publicly available at https://github.com/amromics/amromics under an MIT license.

Synergistic Antimicrobial Activity of Biogenic Silver Nanoparticles and Acanthospermum australe Essential Oil against Skin Infection Pathogens.

In response to the steady increase in antimicrobial-resistant strains, the World Health Organisation has emphasised the need to investigate new antimicrobial agents and alternative therapies that improve the spectrum of activity and reduce the dose required, thus improving safety. This study focused on the characterisation of Acanthospermum australe essential oil and green-synthesis silver nanoparticles (AgNP), evaluating their cytotoxicity in human cells, antimicrobial activity and synergistic effect against pathogens causing skin infections. The main components of the essential oil were germacrene A (24.07%), γ-cadinene (21.47%) and trans-caryophyllene (14.97%). Spherical AgNP with a diameter of 15 ± 3 nm were synthesised. The essential oil showed antimicrobial activity against dermatophytes and Malassezia globosa, while AgNP were found to be active against bacteria, yeasts and dermatophytes. Both compounds were found to be primarily non-cytotoxic at the concentrations required to inhibit microbial growth. Furthermore, the combined use of essential oil and AgNP showed a synergistic antimicrobial effect against dermatophytes and M. globosa. In conclusion, the results suggest that the combined use of bioactive compounds from natural sources, such as essential oil and biogenic AgNP, has the potential to improve antimicrobial efficacy against specific skin pathogens, particularly Microsporum canis, Nannizzia gypsea and M. globosa.

Multiple impacts of the COVID-19 pandemic and antimicrobial stewardship on antimicrobial resistance in nosocomial infections: an interrupted time series analysis.

The emergency response to the COVID-19 pandemic may disrupt hospital management activities of antimicrobial resistance (AMR). This study aimed to determine the changing AMR trend over the period in China when stringent COVID-19 response measures were implemented. This retrospective study was conducted in a designated hospital for COVID-19 patients in Guangzhou, China from April 2018 to September 2021. The prevalence of 13 antimicrobial-resistant bacteria was compared before and after the COVID-19 responses through Chi-square tests. Interrupted time series (ITS) models on the weekly prevalence of AMR were established to determine the changing trend. Controlled ITS models were performed to compare the differences between subgroups. A total of 10,134 isolates over 1,265 days were collected. And antimicrobial-resistant strains presented in 38.6% of the testing isolates. The weekly AMR prevalence decreased by 0.29 percentage point (95% CI [0.05-0.80]) after antimicrobial stewardship (AMS) policy, despite an increase in the prevalence of penicillin-resistant Streptococcus pneumoniae (from 0/43 to 15/43, p < 0.001), carbapenem-resistant Escherichia coli (from 20/1254 to 41/1184, p = 0.005), and carbapenem-resistant Klebsiella pneumoniae (from 93/889 to 114/828, p = 0.042). And the changing trend did not vary by gender (male vs. female), age (<65 vs. ≥65 years), service setting (outpatient vs. inpatient), care unit (ICU vs. non-ICU), the primary site of infection (Lung vs. others), and Gram type of bacteria (positive vs. negative). The response to COVID-19 did not lead to an increase in overall AMR; however, it appears that management strategy on the prudent use of antimicrobials likely contributed to a sizable long-term drop. The frequency of several multidrug-resistant bacteria continues to increase after the COVID-19 epidemic. It is crucial to continue to monitor AMR when COVID-19 cases have surged in China after the relaxation of restriction measures.

The Oral Cavity-Another Reservoir of Antimicrobial-Resistant Staphylococcus aureus?

Staphylococcus aureus is one of the most common potentially pathogenic bacteria that may asymptomatically colonize many sites of healthy carriers. Non-nasal carriage, especially in the oral cavity, and its role in transmitting antimicrobial-resistant S. aureus strains in the healthcare community, is poorly understood. This study aimed to assess the prevalence and antimicrobial susceptibility of S. aureus in both oral and nasal cavities among preclinical dentistry students. A total of 264 oral and nasal swabs were taken from 132 participants, and all specimens were cultured using standard diagnostic procedures and antimicrobial susceptibility testing (EUCAST). The prevalence of S. aureus exclusively in the nasal (11.4%) or oral (9.1%) cavity was comparable, while concurrent oral and nasal carriage was present in 27.3% of participants. Although antibiotic resistance rates observed in both oral and nasal isolates were similar (ranging from 2.7% to 95.5%), 16.7% of carriers exhibited distinct antibiotic resistance profiles between oral and nasal isolates. Three (2.7%) methicillin-resistant S. aureus (MRSA) were isolated from the mouth and nose but multidrug resistance (27.3%) was more frequent in the oral than in the nasal isolates: 34% and 21.1%, respectively. This study demonstrated that preclinical dentistry students have a similar rate of oral S. aureus carriage as the nasal carriage rate, and that the oral cavity can be colonized by antimicrobial-resistant strains that do not originate from the nose. Consequently, the oral cavity seems to be an unjustly overlooked body site in screening for S. aureus carriage.

Current challenges and improvements in assessing the immunogenicity of bacterial vaccines.

The increase in antimicrobial-resistant bacterial strains has highlighted the need for a new vaccine strategy. The primary goal of a candidate vaccine is to prevent disease, by inducing a persistent immunologic memory, through the activation of pathogen-specific immune response. Antibody titer is the main parameter used to assess the immunogenicity of bacterial vaccine candidates and it is the most widely used as a correlate of protection. On the other hand, the antibody titer alone cannot provide complete information on all the activity mediated by antibodies which can only be assessed by functional assays, like the serum bactericidal assay and the opsonophagocytosis assay. However, due to the involvement of many biological factors, these assays are difficult to standardize. Some improvements have been achieved in recent years, but further optimizations are needed to minimize inter- and intra-laboratories variability and to allow the applicability of these functional assays for the vaccine immunogenicity assessment on a larger scale.

Escherichia coli Strains Isolated from American Bison (Bison bison) Showed Uncommon Virulent Gene Patterns and Antimicrobial Multi-Resistance.

E. coli is considered one of the most important zoonotic pathogens worldwide. Highly virulent and antimicrobial-resistant strains of E. coli have been reported in recent years, making it essential to understand their ecological origins. In this study, we analyzed the characteristics of E. coli strains present in the natural population of American bison (Bison bison) in Mexico. We sampled 123 individuals and determined the presence of E. coli using standard bacteriological methods. The isolated strains were characterized using molecular techniques based on PCR. To evaluate the diversity of E. coli strains in this population, we analyzed 108 suggestive colonies from each fecal sample. From a total of 13,284 suggestive colonies, we isolated 33 E. coli strains that contained at least one virulence gene. The virotypes of these strains were highly varied, including strains with atypical patterns or combinations compared to classical pathotypes, such as the presence of escV, eae, bfpB, and ial genes in E. coli strain LMA-26-6-6, or stx2, eae, and ial genes in E. coli strain LMA-16-1-32. Genotype analysis of these strains revealed a previously undescribed phylogenetic group. Serotyping of all strains showed that serogroups O26 and O22 were the most abundant. Interestingly, strains belonging to these groups exhibited different patterns of virulence genes. Finally, the isolated E. coli strains demonstrated broad resistance to antimicrobials, including various beta-lactam antibiotics.

Isolamento e sensibilidade antimicrobiana de Staphylococcus sp. e Escherichia coli de peixe-boi-da-amazônia (Trichechus inunguis) em cativeiro

ABSTRACT: The Amazonian manatee (Trichechusinunguis) is an aquatic mammal threatened with extinction. However, few studies have investigated the pathogens in this species, which may affect both animal and human health. This study aimed to evaluate the frequency, distribution, and patterns of antimicrobial susceptibility of Staphylococcus spp. and Escherichiacoli colonizing the nasal and rectal cavities of Amazonian manatees kept in captivity at the National Institute for Amazonian Research (INPA) in the state of Amazonas, Brazil. Rectal and nasal swabs from 44 manatees of different ages were used in this study. The genus Staphylococcus was isolated from the nasal swabs of 32 (72.7%) animals, with two individuals harboring more than one species of Staphylococcus. S. sciuri was the most commonly isolated species. Resistance to penicillin was observed in 13 (40.6%) isolates, more frequent than the other antimicrobials tested (P = 0.01). E. coli was isolated from the rectal swabs of all animals, with phylogroup B1 being the most frequent among the strains obtained (P = 0.0008). Four isolates (6.8%) were positive for virulence factors, three of which were classified as enterotoxigenicE. coli (ETEC) and one as enteropathogenicE. coli (EPEC). To our knowledge, this is the first study to evaluate Staphylococcus spp. and E. coli in Amazonian manatee samples. This study revealed nasal colonization by Staphylococcus spp., mainly S. sciuri, and diarrheagenicE. coli isolates, including antimicrobial-resistant strains.

Application of MALDI-TOF MS to Identify and Detect Antimicrobial-Resistant Streptococcus uberis Associated with Bovine Mastitis.

Streptococcus uberis is a common bovine mastitis pathogen in dairy cattle. The rapid identification and characterization of antimicrobial resistance (AMR) in S. uberis plays an important role in its diagnosis, treatment, and prevention. In this study, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to identify S. uberis and screen for potential AMR biomarkers. Streptococcus uberis strains (n = 220) associated with bovine mastitis in northern Thailand were identified using the conventional microbiological methods and compared with the results obtained from MALDI-TOF MS. Streptococcus uberis isolates were also examined for antimicrobial susceptibility using a microdilution method. Principal component analysis (PCA) and the Mann-Whitney U test were used to analyze the MALDI-TOF mass spectrum of S. uberis and determine the difference between antimicrobial-resistant and -susceptible strains. Using MALDI-TOF MS, 73.18% (161/220) of the sampled isolates were identified as S. uberis, which conformed to the identifications obtained using conventional microbiological methods and PCR. Using PCR, antimicrobial-resistant strains could not be distinguished from antimicrobial-susceptible strains for all three antimicrobial agents, i.e., tetracycline, ceftiofur, and erythromycin. The detection of spectral peaks at 7531.20 m/z and 6804.74 m/z was statistically different between tetracycline- and erythromycin-resistant and susceptible strains, respectively. This study demonstrates a proteomic approach for the diagnosis of bovine mastitis and potentially for the surveillance of AMR among bovine mastitis pathogens.

Innovative Delivery System Combining CRISPR-Cas12f for Combatting Antimicrobial Resistance in Gram-Negative Bacteria.

Antimicrobial resistance poses a significant global challenge, demanding innovative approaches, such as the CRISPR-Cas-mediated resistance plasmid or gene-curing system, to effectively combat this urgent crisis. To enable successful curing of antimicrobial genes or plasmids through CRISPR-Cas technology, the development of an efficient broad-host-range delivery system is paramount. In this study, we have successfully designed and constructed a novel functional gene delivery plasmid, pQ-mini, utilizing the backbone of a broad-host-range Inc.Q plasmid. Moreover, we have integrated the CRISPR-Cas12f system into the pQ-mini plasmid to enable gene-curing in broad-host of bacteria. Our findings demonstrate that pQ-mini facilitates the highly efficient transfer of genetic elements to diverse bacteria, particularly in various species in the order of Enterobacterales, exhibiting a broader host range and superior conjugation efficiency compared to the commonly used pMB1-like plasmid. Notably, pQ-mini effectively delivers the CRISPR-Cas12f system to antimicrobial-resistant strains, resulting in remarkable curing efficiencies for plasmid-borne mcr-1 or blaKPC genes that are comparable to those achieved by the previously reported pCasCure system. In conclusion, our study successfully establishes and optimizes pQ-mini as a broad-host-range functional gene delivery vector. Furthermore, in combination with the CRISPR-Cas system, pQ-mini demonstrates its potential for broad-host delivery, highlighting its promising role as a novel antimicrobial tool against the growing threat of antimicrobial resistance.

Short-chain fatty acids inhibit bacterial plasmid transfer through conjugation in vitro and in ex vivo chicken tissue explants.

The animal gut acts as a potent reservoir for spreading and maintaining conjugative plasmids that confer antimicrobial resistance (AMR), fitness, and virulence attributes. Interventions that inhibit the continued emergence and expansion of AMR and virulent strains in agricultural and clinical environments are greatly desired. This study aims to determine the presence and efficacy of short-chain fatty acids (SCFA) inhibitory effects on the conjugal transfer of AMR plasmids. In vitro broth conjugations were conducted between donor Escherichia coli strains carrying AMP plasmids and the plasmid-less Escherichia coli HS-4 recipient strain. Conjugations were supplemented with ddH2O or SCFAs at 1, 0.1, 0.01, or 0.001 molar final concentration. The addition of SCFAs completely inhibited plasmid transfer at 1 and 0.1 molar and significantly (p < 0.05) reduced transfer at 0.01 molar, regardless of SCFA tested. In explant models for the chicken ceca, either ddH2O or a final concentration of 0.025 M SCFAs were supplemented to the explants infected with donor and recipient E. coli. In every SCFA tested, significant decreases in transconjugant populations compared to ddH2O-treated control samples were observed with minimal effects on donor and recipient populations. Finally, significant reductions in transconjugants for plasmids of each incompatibility type (IncP1ε, IncFIβ, and IncI1) tested were detected. This study demonstrates for the first time the broad inhibition ability of SCFAs on bacterial plasmid transfer and eliminates AMR with minimal effect on bacteria. Implementing interventions that increase the concentrations of SCFAs in the gut may be a viable method to reduce the risk, incidence, and rate of AMR emergence in agricultural and human environments.

Effects of a Mining Dam Disaster on Antimicrobial-Resistant and Metal-Tolerant Bacterial Strains Recovered from Environmental Samples

Effects of a Mining Dam Disaster on Antimicrobial-Resistant and Metal-Tolerant Bacterial Strains Recovered from Environmental Samples

The Impact of Enterococcus spp. in the Immunocompromised Host: A Comprehensive Review.

The immunocompromised host is usually vulnerable to infectious diseases due to broad-spectrum treatments and immunological dysregulation. The Enterococcus genus consists of normal gut commensals, which acquire a leading role in infective processes among individuals with compromised immune systems. These microorganisms may express a potential virulence and resistance spectrum, enabling their function as severe pathogens. The Enterococcus spp. infections in immunocompromised hosts appear to be difficult to resolve due to the immunological response impairment and the possibility of facing antimicrobial-resistant strains. As regards the related risk factors, several data demonstrated that prior antibiotic exposure, medical device insertion, prolonged hospitalization and surgical interventions may lead to Enterococcus overgrowth, antibiotic resistance and spread among critical healthcare settings. Herein, we present a comprehensive review of Enterococcus spp. in the immunocompromised host, summarizing the available knowledge about virulence factors, antimicrobial-resistance mechanisms and host-pathogen interaction. The review ultimately yearns for more substantial support to further investigations about enterococcal infections and immunocompromised host response.

Surveillance of Antimicrobial Resistance of Escherichia coli Isolates from Intestinal Contents of Dairy and Veal Calves in the Veneto Region, Northeaster Italy.

This surveillance study aimed to estimate the proportion of antimicrobial resistant strains and antimicrobial resistance (AMR) profiles of E. coli isolates detected from the intestinal contents of veal and dairy calves in the Veneto Region, Northeaster Italy. Additionally, we investigated the differences in AMR profiles between dairy and veal calves over the period 2017-2022. Overall 1150 E. coli isolates were tested from calves exhibiting enteric disease, with 868 from dairy and 282 from veal calves. The percentage of resistant isolates to nine antimicrobials was notably higher in veal calves compared to dairy calves, except for ampicillin. Throughout the study period, we observed a significant increase in the proportion of resistant isolates to florfenicol, gentamycin, paromomycin, tetracycline and trimethoprim/sulfamethoxazole in dairy calves, while we did not detect any significant increase in the proportion of resistant isolates among veal calves. A substantial proportion (75.9%) of the isolated E. coli exhibited multi-drug resistance (MDR). The proportion of multi-drug resistant isolates was significantly higher in veal calves (91.7%) compared to dairy calves (74.3%) all through the surveillance period (2017-2022), with no significant variation in MDR proportion among veal calves between 2017 and 2022 but a significant increase among dairy calves.

Molecular insights intoexpression and silencing of resistance determinants in Staphylococcus aureus.

This study aimed to investigate the status of antimicrobial-resistant strains of Staphylococcus aureus in Pakistan, their association in terms of co-occurrence with the biofilm-forming genes, resistance profiling and associated discrepancies in diagnostic methods. A total of 384 milk samples from bovine was collected by using convenient sampling technique and were initially screened for subclinical mastitis, further preceded by isolation and confirmation of S. aureus. The S. aureus isolates were subjected to evaluation of antimicrobial resistance by phenotypic identification using Kirby-Bauer disc diffusion method, while the genotypic estimation was done by polymerase chain reaction to declare isolates as methicillin, beta-lactam, vancomycin, tetracycline, and aminoglycoside resistant S. aureus (MRSA, BRSA, VRSA, TRSA, and ARSA), respectively. The current study revealed an overall prevalence of subclinical mastitis and S. aureus to be 59.11% and 46.69%, respectively. On a phenotypic basis, the prevalence of MRSA, BRSA, VRSA, TRSA, and ARSA was found to be 44.33%, 58.49%, 20.75%, 35.84%, and 30.18%, respectively. The results of PCR analysis showed that 46.80% of the tested isolates were declared as MRSA, 37.09% as BRSA, and 36.36% as VRSA, while the occurrence of TRSA and ARSA was observed in 26.31% and 18.75%, respectively. The current study also reported the existence of biofilm-producing genes (icaA and icaD) in 49.06% and 40.57% isolates, respectively. Lastly, this study also reported a high incidence of discrepancies for both genotypic and phenotypic identification methods of resistance evaluation, with the highest discrepancy ratio for the accA-aphD gene, followed by tetK, vanB, blaZ, and mecA genes. The study concluded that different antibiotic resistance strains of S. aureus are prevalent in study districts with high potential to transmit between human populations. The study also determined that there are multiple resistance determinants and mechanisms that are responsible for the silencing and expression of antibiotic resistance genes.

Making the leap from technique to treatment - genetic engineering is paving the way for more efficient phage therapy.

Bacteriophages (phages) are viruses specific to bacteria that target them with great efficiency and specificity. Phages were first studied for their antibacterial potential in the early twentieth century; however, their use was largely eclipsed by the popularity of antibiotics. Given the surge of antimicrobial-resistant strains worldwide, there has been a renaissance in harnessing phages as therapeutics once more. One of the key advantages of phages is their amenability to modification, allowing the generation of numerous derivatives optimised for specific functions depending on the modification. These enhanced derivatives could display higher infectivity, expanded host range or greater affinity to human tissues, where some bacterial species exert their pathogenesis. Despite this, there has been a noticeable discrepancy between the generation of derivatives in vitro and their clinical application in vivo. In most instances, phage therapy is only used on a compassionate-use basis, where all other treatment options have been exhausted. A lack of clinical trials and numerous regulatory hurdles hamper the progress of phage therapy and in turn, the engineered variants, in becoming widely used in the clinic. In this review, we outline the various types of modifications enacted upon phages and how these modifications contribute to their enhanced bactericidal function compared with wild-type phages. We also discuss the nascent progress of genetically modified phages in clinical trials along with the current issues these are confronted with, to validate it as a therapy in the clinic.

Nanoantibiotics: A Tool Against Antimicrobial Resistance

Antimicrobial Resistance (AMR), is one of the biggest emerging threats to human health and healthcare systems. Experts are suggesting that the post-antibiotic era, in which microbial infections and minor injuries will again become fatal, is near. A report published by the Antibiotics Resistance Collaborators, in the Lancet,reported that 1.27 million people died due to antibiotic-resistant bacterial infections in 2019.1 Deaths could reach 10 million by 2050 if the problem is not addressed. Antimicrobial resistance arises as a natural adaptation of microorganisms to environmental challenges. One typical self-defense mechanism is by producing enzymes that inactivate antimicrobial agents. Bacteria can also become resistant to β-lactams by producing β-lactamase, and by altering binding sites for antimicrobials agents (resistance to glycopeptide antibiotic agents), expressing multidrug efflux pumps such as tigecycline resistance to Acinetobacter baumannii, and limiting cell permeability for antibiotics such as Acinetobacter baumannii and pseudomonas aeruginosa.2,3th In the early 20 century, infectious diseases were the major cause of death. The advent of antibiotics led to a significant decrease in mortality.4 However, antibiotics resistance has now reached a threshold that is invalidating commonly used antibiotic agents. Currently the attempts to manage microbial resistance to antibiotics include the development of novel antimicrobial agents. However, there is no guarantee that the introduced new antimicrobial agents would be able to cope with the microbial resistance effectively andefficiently.5 Apart from developing new antibiotics, the chemical modification of existing antimicrobial agents is emerging as an upcoming strategy to combat antimicrobial resistance.4-6 Research on the effect of antibiotic associated nanoparticles on bacterial function is being conducted with the hope that advances in nanotechnology will lead to strategies for reconfiguration of presently available antibiotic molecules.Several nanomaterials have been identified as alternates for combating antimicrobial resistant strains. Each metallic and ceramic nanomaterials and more specifically their nanoparticles have their own peculiar antimicrobial properties. Studies have reported that these nanoparticles can be surface-functionalized withantimicrobial agents or molecules to further enhance their antimicrobial efficacy.6 Engineering antibiotics into nanoscale or functionalizing nanoparticles with antibiotic agents allows them to penetrate microbial cells and reach their target sites with precision and accuracy. Studies have shown that in contrast to free antibiotics, tailored functionalized nanoparticles and small antibiotic molecules have improved binding affinities andtarget specificity.6 Currently, these nanotechnology-based solutions have reported some problems like cytotoxicity, targeted selectivity, and bulk production. However, with concrete planning and a cohesive approach from academia, industry, and government, the development of nanoantibiotics drugs of unique shapes and sizes, high surface areas, ability to carry antibiotic drugs to target sites, and protein disruption will help overcome antimicrobial resistance. Editor-in-Chief How to cite this: Alamgir W, Adnan H. Nanoantibiotics: A Tool Against Antimicrobial Resistance. Life and Science. 2024; 5(2): 130-131. doi: http://doi.org/10.37185/LnS.1.1.657

Exploring Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli in Food-Producing Animals and Animal-Derived Foods.

Antimicrobials serve as crucial treatments in both veterinary and human medicine, aiding in the control and prevention of infectious diseases. However, their misuse or overuse has led to the emergence of antimicrobial resistance, posing a significant threat to public health. This review focuses on extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in animals and their associated food products, which contribute to the proliferation of antimicrobial-resistant strains. Recent research has highlighted the presence of ESBL-producing E. coli in animals and animal-derived foods, with some studies indicating genetic similarities between these isolates and those found in human infections. This underscores the urgent need to address antimicrobial resistance as a pressing public health issue. More comprehensive studies are required to understand the evolving landscape of ESBLs and to develop strategic public health policies grounded in the One Health approach, aiming to control and mitigate their prevalence effectively.

Isolation, prevalence of bacteria and fungi from carcasses and different locations within Yola abattoir and antimicrobial resistance profile of Escherichia coli O157:H7

The absence of modern slaughtering facilities and an unhygienic environment in Yola abattoir may result in an outbreak of antibiotic-resistant pathogenic microorganisms, leading to economic loss and human death. Hence, this study was carried out to isolate and assess the prevalence of bacteria and fungi within the abattoir environment as well as to determine the antimicrobial resistance profile of E. coli O157:H7 from different locations and carcasses. A cross-sectional study was conducted where a simple random sampling method was used for sampling. A total of 156 samples were collected. Isolation and identification of bacteria and fungi were done using standard methods. Pseudomonas was the most dominant bacterial species with a total of 151 isolates, followed by E. coli 143 and Klebsiella with 123 isolates. The highest prevalence in fungi was recorded in Aspergillus flavus at 17.6 %, followed by Aspergillus niger at 15.1 % and Trichophyton rubrum and Penicillium that had 14.5 % respectively. The highest mean air-borne coliform count was in the Lairage, it ranged between 1.1 x 106 CFU/m3 and 1.7 x 106 CFU/m3. A hundred and forty-three E. coli were isolated out of which six (4.2 %) were characterized to be E. coli O157:H7 producing characteristic colorless colonies on cefixime tellurite sorbitol MacConkey (CT-SMAC) agar. All the six E. coli O157:H7 were resistant to at least two antibiotics, ampicillin, and amoxicillin-clavulanic acid while ciprofloxacin, trimethoprim-sulfamethoxazole, and tetracycline were effective against the six E. coli O157:H7. The MAR ranged between 0.2 and 0.7. The results obtained in this study showed that there is a need for modern facilities in Yola abattoir, training of workers on hygiene, and a hygienic environment to avoid microbial contamination and spread of antimicrobial-resistant pathogenic strains like E. coli O157:H7 and mycotoxin producer Aspergillus flavus.

Feasibility of using a combination of staphylococcal superantigen-like proteins 3, 7 and 11 in a fusion vaccine for Staphylococcus aureus.

Staphylococcus aureus is a significant bacterial pathogen in both community and hospital settings, and the escalation of antimicrobial-resistant strains is of immense global concern. Vaccination is an inviting long-term strategy to curb staphylococcal disease, but identification of an effective vaccine has proved to be challenging. Three well-characterized, ubiquitous, secreted immune evasion factors from the staphylococcal superantigen-like (SSL) protein family were selected for the development of a vaccine. Wild-type SSL3, 7 and 11, which inhibit signaling through Toll-like receptor 2, cleavage of complement component 5 and neutrophil function, respectively, were successfully combined into a stable, active fusion protein (PolySSL7311). Vaccination of mice with an attenuated form of the PolySSL7311 protein stimulated significantly elevated specific immunoglobulin G and splenocyte proliferation responses to each component relative to adjuvant-only controls. Vaccination with PolySSL7311, but not a mixture of the individual proteins, led to a > 102 reduction in S.aureus tissue burden compared with controls after peritoneal challenge. Comparable antibody responses were elicited after coadministration of the vaccine in either AddaVax (an analog of MF59) or an Alum-based adjuvant; but only AddaVax conferred a significant reduction in bacterial load, aligning with other studies that suggest both cellular and humoral immune responses are necessary for protective immunity to S. aureus. Anti-sera from mice immunized with PolySSL7311, but not individual proteins, partially neutralized the functional activities of SSL7. This study confirms the importance of these SSLs for the survival of S. aureus in vivo and suggests that PolySSL7311 is a promising vaccine candidate.