Frontiers in antibiotics最新文献

{"title":"Screening Amazon rainforest plant extracts for antimicrobial activity: a 15-year commitment to the Brazilian biodiversity.","authors":"Ivana Barbosa Suffredini, Jefferson de Souza Silva, Sergio Alexandre Frana, Katia Cristina Pinto, Keli Cristina Dias Bento, Erika Costa Rudiger, Paloma Kelly de Souza Belo, José Rodrigo de Arruda, Juliana Paola Schulze, Adriana Lígia de Castilho, Livia Roberta Piedade Camargo, Ricardo Olivieri Paulino, Yasmin de Oliveira Santos, Raphael Assis Leandro Morais, Karen Cristina Comin Maldonado, Gabriele Kolndorfer, Karolayne da Silva, Pietra Dantas de Jesus, Gabriella de Oliveira Moura, Victoria Rocha Brandão, Hevelton Araújo Ribeiro, Christian Henrique Komka Vara, Fabiane Massola, Ingrit Elida Collantes Díaz, Mateus Luís Barradas Paciencia, Selene Dall'Acqua Coutinho, Riad Naim Younes, Antonio Drauzio Varella","doi":"10.3389/frabi.2023.1122400","DOIUrl":"10.3389/frabi.2023.1122400","url":null,"abstract":"<p><strong>Introduction: </strong>The need for new tools to treat infections is constantly growing due to the possibilities of emerging diseases related to environmental changes, climatic catastrophes, microorganism resistance, and human and animal aging, leading to an evident unbalance in the planet's health. Brazil contains the most significant portion of world biodiversity, a potential source of new antimicrobial natural products. Nonetheless, its environment, particularly its forests, and rainforests, is under threat, meaning that rapidly conducted, comprehensive research into the potential of antimicrobial activity to address this threat is urgently needed.</p><p><strong>Methods: </strong>In this study, plants from the Amazon rainforest and the Atlantic forests were collected and tested against several pathogenic microbes relevant to humans, animals, and the environment, and subjected to large-scale susceptibility assays, bioautography, and <i>Artemia salina</i> toxicity assays. From the plants, 2,280 organic and aqueous extracts were obtained from different organs, namely leaves, barks, flowers, fruits, and seeds, and subjected to a large-scale susceptibility screening assay against <i>Staphylococcus aureus</i>, <i>Staphylococcus epidermidis</i>, <i>Enterococcus faecalis</i>, <i>Streptococcus mutans</i>, <i>Streptococcus sanguinis</i>, <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>, <i>Candida albicans</i>, <i>Malassezia pachydermatis</i>, <i>Malassezia furfur</i>, and <i>Listeria monocytogenes</i>.</p><p><strong>Results and discussion: </strong>The selected extracts were subjected to antimicrobial susceptibility tests to determine their inhibition zone diameters and minimum bactericidal concentrations, to bioautography, and to an <i>Artemia salina</i> toxicity assay, which resulted in 154 active extracts. Moreover, 111 out of 154 extracts were ranked based on scores established by the <i>p</i>-values and the mean rank differences in each set of test results. The final ranking identified which extracts should be studied in further phytochemical research using thin-layer chromatography techniques as a priority. The extracts obtained from plants belonging to Combretaceae, Connaraceae, Convolvulaceae, Fabaceae, Malpighiaceae, Moraceae, Piperaceae, Polygonaceae, and Salicaceae were selected as the most promising ones and used to support the identification of plant-based antimicrobial active compounds from the immense biodiversity of Brazilian forests.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":"1 1","pages":"1122400"},"PeriodicalIF":0.0,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732023/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41470766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drug-resistant bacteria in the critically ill: patterns and mechanisms of resistance and potential remedies.","authors":"Riaz M Karukappadath, Dumitru Sirbu, Ahmed Zaky","doi":"10.3389/frabi.2023.1145190","DOIUrl":"10.3389/frabi.2023.1145190","url":null,"abstract":"<p><p>Antimicrobial resistance in the intensive care unit is an ongoing global healthcare concern associated with high mortality and morbidity rates and high healthcare costs. Select groups of bacterial pathogens express different mechanisms of antimicrobial resistance. Clinicians face challenges in managing patients with multidrug-resistant bacteria in the form of a limited pool of available antibiotics, slow and potentially inaccurate conventional diagnostic microbial modalities, mimicry of non-infective conditions with infective syndromes, and the confounding of the clinical picture of organ dysfunction associated with sepsis with postoperative surgical complications such as hemorrhage and fluid shifts. Potential remedies for antimicrobial resistance include specific surveillance, adequate and systematic antibiotic stewardship, use of pharmacokinetic and pharmacodynamic techniques of therapy, and antimicrobial monitoring and adequate employment of infection control policies. Novel techniques of combating antimicrobial resistance include the use of aerosolized antibiotics for lung infections, the restoration of gut microflora using fecal transplantation, and orally administered probiotics. Newer antibiotics are urgently needed as part of the armamentarium against multidrug-resistant bacteria. In this review we discuss mechanisms and patterns of microbial resistance in a select group of drug-resistant bacteria, and preventive and remedial measures for combating antibiotic resistance in the critically ill.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1145190"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732010/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46188272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevalence and genetic characterization of clinically relevant extended-spectrum β-lactamase-producing <i>Enterobacterales</i> in the Gulf Cooperation Council countries.","authors":"Hamad A Hadi, Hissa Al-Hail, Leena Elsheikh Aboidris, Mahmood Al-Orphaly, Mazen A Sid Ahmed, Bincy Gladson Samuel, Hana Adam Mohamed, Ali A Sultan, Sini Skariah","doi":"10.3389/frabi.2023.1177954","DOIUrl":"10.3389/frabi.2023.1177954","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Introduction: &lt;/strong&gt;Among Gram-negative bacteria (GNB), &lt;i&gt;Enterobacterales&lt;/i&gt; (&lt;i&gt;Enterobacterales&lt;/i&gt;), such as &lt;i&gt;Escherichia coli&lt;/i&gt; (&lt;i&gt;E. coli&lt;/i&gt;) and &lt;i&gt;Klebsiella pneumoniae&lt;/i&gt; (&lt;i&gt;K. pneumoniae&lt;/i&gt;), are the most clinically relevant pathogens in healthcare settings. Infections secondary to these pathogens are widely common but multidrug resistance (MDR) in &lt;i&gt;Enterobacterales&lt;/i&gt; has become a significant challenge with increased morbidity, mortality, and cost of management. The escalating global prevalence of MDR in &lt;i&gt;Enterobacterales&lt;/i&gt; has led to limited treatment options, raising an urgent need for novel antimicrobial therapy(s) and detailed studies exploring underlying resistance mechanisms. In &lt;i&gt;Enterobacterales&lt;/i&gt;, the prime antimicrobial resistance mechanism against β-lactam antibiotics is mainly the production of β-lactamases, particularly extended-spectrum β-lactamases (ESBLs). Although the Gulf region is witnessing major challenges from infections secondary to MDR GNB, the extent of the problem has not been fully evaluated. Therefore, this review aims to address the prevalence and genetic characterization of ESBL-producing &lt;i&gt;Enterobacterales&lt;/i&gt; in the Gulf Cooperation Council (GCC) countries.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;PubMed® (National Library of Medicine, Bethesda, MD, USA) search was conducted, which looked for academic articles discussing the epidemiology of MDR &lt;i&gt;Enterobacterales&lt;/i&gt; in the GCC countries, published in the last 5 years.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results and conclusions: &lt;/strong&gt;In GCC countries there is a high prevalence rate of MDR &lt;i&gt;Enterobacterales&lt;/i&gt;, particularly ESBLs. Prevalence rates of ESBL-producing &lt;i&gt;Enterobacterales&lt;/i&gt; among the &lt;i&gt;Enterobacterales&lt;/i&gt; in general clinical samples in the GCC region is 21.6%-29.3%, with a slightly higher prevalence rate in intensive care unit patients (17.3-31.3%) and in patients with urinary tract infections (25.2%-31.7%). ESBL carriers have also been noted in the general community. ESBL-producing &lt;i&gt;Enterobacterales&lt;/i&gt; from the GCC region show high levels of resistance to ampicillin, aztreonam, third-/fourth-generation cephalosporins, fluoroquinolones, and trimethoprim-sulfamethoxazole. Intermediate resistance rates are observed against nitrofurantoin, piperacillin/tazobactam, and gentamicin, with increasing resistance observed against tigecycline. The isolates demonstrate low-level resistance to carbapenems, fosfomycin, colistin, and amikacin. &lt;i&gt;Enterobacterales&lt;/i&gt; isolates that are concomitant ESBL producers and are carbapenem resistant have been increasingly reported and demonstrate alarmingly increased antibiotic resistance patterns compared with ESBL &lt;i&gt;Enterobacterales&lt;/i&gt;. The most prevalent genes for ESBL resistance in the &lt;i&gt;Enterobacterales&lt;/i&gt; isolates in the GCC region are: &lt;i&gt;bla&lt;/i&gt; &lt;sub&gt;CTX-M&lt;/sub&gt; (subtype group 1) followed by/co-dominated by &lt;i&gt;bla&lt;/i&gt; &lt;sub&gt;TEM&lt;/sub&gt; and &lt;i&gt;bla&lt;/i&gt; &lt;sub&gt;SHV&lt;/sub&gt;, whereas the most commo","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1177954"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732020/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48009600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends in antimicrobial susceptibility patterns of bacterial isolates in Lahore, Pakistan.","authors":"Nauman Khalid, Zunaira Akbar, Nosheen Mustafa, Jamshaid Akbar, Shanawar Saeed, Zikria Saleem","doi":"10.3389/frabi.2023.1149408","DOIUrl":"10.3389/frabi.2023.1149408","url":null,"abstract":"<p><strong>Background: </strong>Antimicrobial resistance (AMR) has provoked a global health issue. Antimicrobial stewardship programs should be implemented to overcome this issue. The aim of this study was to determine the sensitivity patterns of the WHO Access, Watch, Reserve (AWaRe) group of antibiotics that assists in the selection of appropriate empiric antibiotic therapies.</p><p><strong>Method: </strong>A descriptive, cross-sectional study was conducted for 6 months, in which 422 culture sensitivity sample reports from the Ghurki Trust Teaching Hospital's laboratory were obtained through a convenience sampling technique, and the sensitivity patterns of nine offending bacteria to the WHO AWaRe group antibiotics were determined. Descriptive statistics and differences in frequency distribution among the categorical variables were obtained using the Statistical Package for Social Sciences (SPSS) software, version 21.</p><p><strong>Results: </strong>Among 422 culture sensitivity sample reports, <i>Escherichia coli</i> (16.1%) was the most common Gram-negative pathogen. <i>Acinetobacter, E. coli, Klebsiella</i>, and <i>Pseudomonas</i> showed 100% sensitivity to polymyxin-b and colistin. <i>Proteus</i> showed the highest sensitivity to meropenem (90%), <i>Staphylococcus aureus</i> showed a 98% sensitivity to linezolid, <i>Staphylococcus epidermidis</i> was 100% sensitive to vancomycin and linezolid, and <i>Streptococcus</i> showed the highest sensitivity to penicillin (100%) and vancomycin (94.7%). Polymyxin b and colistin were found to be the most effective antibiotics against Gram-negative bacteria (100%). Gram-positive bacteria were highly sensitive to linezolid (99.4%), vancomycin (98.2%), chloramphenicol (89.5%), and tigecycline (82.6%).</p><p><strong>Conclusion: </strong>Culture sensitivity reports help to rationalize the empirical use of antibiotics in clinical practice in addressing the challenge of antimicrobial resistance. This study showed that polymyxin-b and colistin were the most effective antibiotics against Gram-negative isolates and that Gram-positive bacteria were highly susceptible to linezolid. Updated antibiograms should be used by clinicians to evaluate bacterial susceptibility patterns and rationalize antibiotic empiric therapy.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1149408"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11731995/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48379894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial susceptibility testing and tentative epidemiological cut-off values for <i>Lactobacillaceae</i> family species intended for ingestion.","authors":"Katrine Nøhr-Meldgaard, Carsten Struve, Hanne Ingmer, Anna Koza, Kosai Al-Nakeeb, Yvonne Agersø","doi":"10.3389/frabi.2023.1162636","DOIUrl":"10.3389/frabi.2023.1162636","url":null,"abstract":"<p><strong>Introduction: </strong>In this work, 170 strains covering 13 species from the <i>Lactobacillaceae</i> family were analyzed to determine minimal inhibitory concentration (MIC) distributions to nine antimicrobial agents, and genes potentially conferring resistance. This allows a proposal of tentative Epidemiological Cut-Offs (ECOFFs) that follows the phylogeny for interpretation of resistance in the 13 species.</p><p><strong>Methods: </strong>The 170 strains originated from different sources, geographical areas, and time periods. MICs for nine antibiotics were determined according to the ISO 10932 standard for lactobacillia and by a modified CLSI-method for <i>Leuconostoc</i> and <i>Pediococcus</i> which ensured sufficient growth. The strains were whole genome sequenced, subtyped by core genome analysis, and assessed for the presence of antibiotic resistance genes using the ResFinder and NCBI AMRFinder databases.</p><p><strong>Results and discussion: </strong>The data provide evidence that antimicrobial susceptibility follows phylogeny instead of fermentation pattern and accordingly, tentative ECOFFs were defined. For some species the tentative ECOFFs for specific antibiotics are above the cut-off values set by the European Food Safety Authority (EFSA) which are primarily defined according to fermentation pattern or at genus level. The increased tolerance for specific antibiotics observed for some species was evaluated to be innate, as only for one strain phenotypic resistance was found to be related to an acquired resistance gene. In general, more data are needed to define ECOFFs and since the number of isolates available for industrial relevant bacterial species are often limited compared to clinically relevant species, it is important; 1) that strains are unambiguously defined at species level and subtyped through core genome analysis, 2) MIC determination are performed by use of a standardized method to define species-specific MIC distributions and 3) that known antimicrobial resistance genes are determined in whole genome sequences to support the MIC determinations.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1162636"},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732008/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46572607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Allele distribution and phenotypic resistance to ciprofloxacin and gentamicin among extended-spectrum β-lactamase-producing <i>Escherichia coli</i> isolated from the urine, stool, animals, and environments of patients with presumptive urinary tract infection in Tanzania.","authors":"Adam A Mwakyoma, Benson R Kidenya, Caroline A Minja, Martha F Mushi, Alison Sandeman, Wilber Sabiti, Mathew T G Holden, Stephen E Mshana","doi":"10.3389/frabi.2023.1164016","DOIUrl":"10.3389/frabi.2023.1164016","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Additional antimicrobial resistance to extended-spectrum β-lactamase (ESBL)-producing &lt;i&gt;E. coli&lt;/i&gt; exhausts treatment options. We investigated allele distribution and resistance to ciprofloxacin and gentamicin among ESBL-producing &lt;i&gt;E. coli&lt;/i&gt; isolates from the urine, stool, animals, and environments of presumptive urinary tract infection (UTI) patients, in order to gain a crucial insight toward devising prevention and control measures and treatment guidelines.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Archived ESBL-producing &lt;i&gt;E. coli&lt;/i&gt; isolates from the urine, stool, animals, and surrounding environments of presumptive UTI patients were retrieved. Antimicrobial susceptibility profiles for ciprofloxacin and gentamicin were done followed by multiplex Polymerase chain reaction (PCR) for &lt;i&gt;bla&lt;sub&gt;CTX-M&lt;/sub&gt;&lt;/i&gt; , &lt;i&gt;bla&lt;sub&gt;TEM&lt;/sub&gt;&lt;/i&gt; , and &lt;i&gt;bla&lt;sub&gt;SHV&lt;/sub&gt;&lt;/i&gt; , to determine ESBL allele distribution. Data were analyzed using STATA version 17.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;A total of 472 confirmed ESBL-producing &lt;i&gt;E. coli&lt;/i&gt; isolates from Mwanza 243 (51.5%), Kilimanjaro 143 (30.3%), and Mbeya 86 (18.2%) were analyzed. Of these, 75 (15.9%) were from urine, 199 (42.2%) from stool, 58 (12.3%) from rectal/cloaca swabs of animals, and 140 (29.7%) from surrounding environments. Out of the 472 ESBL-producing &lt;i&gt;E. coli&lt;/i&gt;, 98.9% (467) had at least one ESBL allele. The most frequent allele was &lt;i&gt;bla&lt;sub&gt;CTX-M&lt;/sub&gt;&lt;/i&gt; , which was detected in 88.1% (416/472) of isolates, followed by the &lt;i&gt;bla&lt;sub&gt;TEM&lt;/sub&gt;&lt;/i&gt; allele, which was detected in 51.5% (243/472) of isolates. A total of 40.7% (192/472) of isolates harbored dual &lt;i&gt;bla&lt;sub&gt;CTX-M&lt;/sub&gt;&lt;/i&gt;  + &lt;i&gt;bla&lt;sub&gt;TEM&lt;/sub&gt;&lt;/i&gt; alleles and only 0.2% (1/472) of isolates had dual &lt;i&gt;bla&lt;sub&gt;CTX-M&lt;/sub&gt;&lt;/i&gt;  + &lt;i&gt;bla&lt;sub&gt;SHV&lt;/sub&gt;&lt;/i&gt; alleles, whereas 2.3% (11/472) of isolates had a combination of all three alleles (&lt;i&gt;bla&lt;sub&gt;CTX-M&lt;/sub&gt;&lt;/i&gt;  + &lt;i&gt;bla&lt;sub&gt;TEM&lt;/sub&gt;&lt;/i&gt;  + &lt;i&gt;bla&lt;sub&gt;SHV&lt;/sub&gt;&lt;/i&gt; ). None of the isolates harbored a combination of &lt;i&gt;bla&lt;sub&gt;TEM&lt;/sub&gt;&lt;/i&gt;  + &lt;i&gt;bla&lt;sub&gt;SHV&lt;/sub&gt;&lt;/i&gt; only. Resistance to ciprofloxacin and gentamicin was observed in 70.8% (334/472) and 46.0% (217/472) of isolates, respectively. There was a significant difference in the distribution of resistance to ciprofloxacin as well as gentamicin among ESBL-producing &lt;i&gt;E. coli&lt;/i&gt; isolated from various sources (&lt;i&gt;p&lt;/i&gt;-value &lt; 0.001 and 0.002, respectively).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;Almost all ESBL-producing &lt;i&gt;E. coli&lt;/i&gt; isolates carry &lt;i&gt;bla&lt;sub&gt;CTX-M&lt;/sub&gt;&lt;/i&gt; , &lt;i&gt;bla&lt;sub&gt;TEM&lt;/sub&gt;&lt;/i&gt; , and &lt;i&gt;bla&lt;sub&gt;SHV&lt;/sub&gt;&lt;/i&gt; either alone or in combination, with the most common allele being &lt;i&gt;bla&lt;sub&gt;CTX-M.&lt;/sub&gt;&lt;/i&gt; The resistance to ciprofloxacin and gentamicin, which are frontline antibiotics for UTIs among ESBL-producing &lt;i&gt;E. coli&lt;/i&gt;, is high. This implies the need to continually revise the local guidelines used for optimal empirical therapy for UTIs, and for continual r","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1164016"},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732152/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44201076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevalence and antimicrobial resistance profile of bacterial foodborne pathogens in Nile tilapia fish (<i>Oreochromis niloticus</i>) at points of retail sale in Nairobi, Kenya.","authors":"Millicent T Mumbo, Evans N Nyaboga, Johnson Kinyua, Edward K Muge, Scholastica G K Mathenge, Geoffrey Muriira, Henry Rotich, Bernard Njiraini, Joshua M Njiru","doi":"10.3389/frabi.2023.1156258","DOIUrl":"10.3389/frabi.2023.1156258","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Proteus spp&lt;/i&gt;., &lt;i&gt;Staphylococcus spp&lt;/i&gt;., &lt;i&gt;Pseudeomonas spp&lt;/i&gt;., and pathogenic Vibrios are among the major foodborne pathogens associated with the consumption of contaminated fish. The increasing occurrence of antimicrobial resistance in these pathogens is a serious public health concern globally and therefore continuous monitoring of antimicrobial resistance of these bacteria along the food chain is crucial for for control of foodborne illnesses. The aim of this study was to assess the prevalence, antimicrobial resistance patterns, antibiotic resistance genes, and genetic diversity of bacterial foodborne pathogens recovered from fresh Nile tilapia (&lt;i&gt;Oreochromis niloticus&lt;/i&gt;) obtained from retail markets in Nairobi, Kenya. A total of 68 &lt;i&gt;O. niloticus&lt;/i&gt; fish with an average weight of 300.12 ± 25.66 g and body length of 23.00 ± 0.82 cm were randomly sampled from retail markets and tested for the presence of &lt;i&gt;Proteus, Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholerae&lt;/i&gt;, and &lt;i&gt;Vibrio parahaemolyticus&lt;/i&gt;. Standard culture-based microbiological and Kirby-Bauer agar disk diffusion methods were used to isolate and determine the antimicrobial resistance patterns of the isolates to 11 selected antibiotics. Statistical analysis was performed using Minitab v17.1, with &lt;i&gt;p&lt;/i&gt; &lt; 0.05 considered significant. The genetic diversity of the multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria was determined using 16S rRNA sequencing and phylogenetic analysis, and polymerase chain reaction (PCR) was used for detection of antibiotic resistance genes in MDR bacterial isolates. High levels of bacterial contamination were detected in fresh &lt;i&gt;O. niloticus&lt;/i&gt; fish (44/68, 64.71%). The most prevalent bacteria were &lt;i&gt;Proteus&lt;/i&gt; spp. (44.12%), with the rest of the bacterial species registering a prevalence of 10.29%, 4.41%, 2.94%, and 2.94% (for &lt;i&gt;S. aureus&lt;/i&gt;, &lt;i&gt;P. aeruginosa&lt;/i&gt;, &lt;i&gt;V. cholerae&lt;/i&gt;, and &lt;i&gt;V. parahaemolyticus&lt;/i&gt;, respectively). Antimicrobial resistance was detected in all the bacteria species and all the isolates were resistant to at least one antibiotic except cefepime (30 µg). Additionally, 86.36% of the isolates exhibited multidrug resistance, with higher multiple antibiotic resistance indices (MAR index &gt;0.3) indicating that fresh &lt;i&gt;O. niloticus&lt;/i&gt; fish were highly contaminated with MDR bacteria. Results of 16S rRNA sequences, BLASTn analysis, and phylogenetic trees confirmed the identified MDR bacterial isolates as &lt;i&gt;Proteus mirabilis&lt;/i&gt; and other &lt;i&gt;Proteus&lt;/i&gt; spp.&lt;i&gt;, S. aureus&lt;/i&gt;, &lt;i&gt;P. aeruginosa&lt;/i&gt;, &lt;i&gt;V. cholerae&lt;/i&gt;, and &lt;i&gt;V. parahaemolyticus&lt;/i&gt;. PCR analysis confirmed the presence of multiple antibiotic resistance genes &lt;i&gt;bla&lt;/i&gt;TEM-1, &lt;i&gt;bla&lt;/i&gt;CMY-2, &lt;i&gt;tet&lt;/i&gt;A, &lt;i&gt;tet&lt;/i&gt;C, &lt;i&gt;Sul&lt;/i&gt;2, &lt;i&gt;dfr&lt;/i&gt;A7, &lt;i&gt;str&lt;/i&gt;A, and &lt;i&gt;aad&lt;/i&gt;A belonging to β-lactamases, tetracycline, sulfonamide, trimethoprim, and aminoglycosides in all the MDR bacterial isolates. There was","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1156258"},"PeriodicalIF":0.0,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11731917/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46063868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"C-1 Substituted isoquinolines potentiate the antimycobacterial activity of rifampicin and ethambutol.","authors":"Liam T Martin, Eleanor D Lamming, Arundhati Maitra, Parisa N Mortazavi, Rebecca Roddan, John M Ward, Sanjib Bhakta, Helen C Hailes","doi":"10.3389/frabi.2023.1095013","DOIUrl":"10.3389/frabi.2023.1095013","url":null,"abstract":"<p><strong>Introduction: </strong>The emergence of extensively drug-resistant strains of <i>Mycobacterium tuberculosis</i> threatens decades of progress in the treatment of a disease which remains one of the leading infectious causes of death worldwide. The development of novel antimycobacterial compounds is therefore essential to reinforce the existing antitubercular drug discovery pipeline. There is also interest in new compounds which can synergize with existing antitubercular drugs and can be deployed as part of a combination therapy. This strategy could serve to delay the emergence of resistance to first-line anti-tuberculosis drugs and increase their efficacy against resistant strains of tuberculosis. Previous research has established that several C-1 substituted tetrahydroisoquinolines have antimycobacterial activity. Here we sought to expand our understanding of their antimycobacterial structure activity relationships and their potential to act as adjunct therapies alongside existing antitubercular drugs.</p><p><strong>Methods: </strong>Three chemical series were synthesised and assayed for their antimycobacterial potency, mammalian cell toxicity, inhibition of whole-cell efflux and synergism with isoniazid, rifampicin, and ethambutol.</p><p><strong>Results: </strong>Several compounds were found to inhibit the growth of mycobacteria. Potent inhibitors of whole-cell efflux were also identified, as well as compounds which exhibited synergism with rifampicin and ethambutol.</p><p><strong>Conclusions: </strong>Structure-activity relationships were identified for antimycobacterial potency, improved selectivity, whole cell efflux inhibition and synergism. Potent whole-cell efflux inhibitors and synergistic compounds were identified, suggesting potential development as adjuncts to existing anti-tuberculosis chemotherapy.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1095013"},"PeriodicalIF":0.0,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11731654/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44117459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extended-spectrum beta-lactamases in poultry in Africa: a systematic review.","authors":"Akeemat O Ayinla, Ana L P Mateus","doi":"10.3389/frabi.2023.1140750","DOIUrl":"10.3389/frabi.2023.1140750","url":null,"abstract":"<p><p>Extended-spectrum beta-lactamase (ESBL)-producing bacteria present a unique problem because of their ability to cause infections that are difficult to treat in animals and humans. The presence of ESBL-<i>Escherichia coli</i> (<i>E. coli</i>) in poultry raises a major public health concern due to the risk of zoonotic transfer <i>via</i> the food chain and direct contact with birds and the environment. This review aimed to determine the frequency of ESBL-producing <i>E. coli</i> and associated ESBL genes in poultry in Africa. Three databases (PubMed, ScienceDirect, and Web of Science) and predetermined websites were searched to identify scientific and grey literature. Studies (1582) were screened at title, abstract, and full-text levels. This review was registered with PROSPERO (CRD42021259872). Thirty-three studies were deemed eligible for this review. Phenotypic ESBL expression was confirmed in 22 studies (66.7%) with a wide range of colonization noted in sampled poultry (1 - 100%). The <i>bla</i> <b>_CTX-M</b> gene was the most commonly isolated with the variants <i>bla</i> <b>_CTX-M-1</b> and <i>bla</i> <b>_CTX-M-15</b> being the most predominant in North and West Africa respectively. ESBL-producing <i>E. coli</i> isolates are frequently detected in poultry in farms and slaughterhouses across Africa thereby posing a potential health risk to humans. The paucity of data however does not allow for inferences to be made about the true extent of ESBLs in poultry in Africa.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":" ","pages":"1140750"},"PeriodicalIF":0.0,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732038/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45297025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A spectrum of non-spore-forming fermentative and non-fermentative Gram-negative bacteria: multi-drug resistance, extended-spectrum beta-lactamase, and carbapenemase production.","authors":"Yasin Desalegn, Adane Bitew, Amanuel Adane","doi":"10.3389/frabi.2023.1155005","DOIUrl":"10.3389/frabi.2023.1155005","url":null,"abstract":"<p><strong>Background: </strong>In developing countries, the co-existence of a high burden of infectious diseases caused by Gram-negative bacteria and the rapid increase and spread of multidrug-resistant bacteria have become a serious health threat.</p><p><strong>Objective: </strong>Profiling of Gram-negative bacteria and determining the magnitude of their antimicrobial resistance among patients.</p><p><strong>Results: </strong>A total of 175 non-spore-forming Gram-negative bacteria were isolated from 873 different clinical samples. Of a total of 175 bacteria, 154 (88%) were fermentative Gram-negative bacteria, while 21 (12%) were non-fermentative Gram-negative bacteria<i>. E. coli</i> with a frequency of 58.3% and <i>K. pneumoniae</i> with a frequency of 18.3% were the predominant fermentative Gram-negative bacteria, while <i>P. aeruginosa</i> 9 (5.1%) and <i>A. baumannii</i> 6 (3.4%) were the predominant non-fermentative Gram-negative bacteria. The highest percentage level of antibiotic resistance was seen against ampicillin (86%), and the lowest against meropenem (9.8). About 49 (28%) Gram-negative bacilli were positive for ESBLase. The overall prevalence rate of MDR bacteria was 80.5%, of which 100% of A. <i>baumannii</i>, 90.6% <i>of K. pneumonia.</i> Sixteen isolates were resistant to meropenem, out of which 11 tested for carbapenemase production. Five of the nine were metallo-lactamase producers, with the remaining four being serine carbapenemase producers.</p><p><strong>Conclusion: </strong>The prevalence of Gram-negative bacterial infection was found to be 20%, with a significant proportion (80.0%) due to fermentative Gram-negative bacteria and the remaining 20% due to non-fermentative Gram-negative bacteria. The study has also demonstrated a high prevalence rate of MDR, ESBLase, and carbapenemase-producing Gram-negative bacteria. Antimicrobial resistance of Gram-negative bacteria should be monitored on a regular basis, and an effective infection control program should be implemented.</p>","PeriodicalId":73065,"journal":{"name":"Frontiers in antibiotics","volume":"2 1","pages":"1155005"},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732051/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42864997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}