Evaluation the kill rate and mutant selection window of danofloxacin against Actinobacillus pleuropneumoniae in a peristaltic pump model.

BACKGROUND: Actinobacillus pleuropneumoniae is a serious pathogen in pigs. The abundant application of antibiotics has resulted in the gradual emergence of drugresistant bacteria, which has seriously affected treatment of disease. To aid measures to prevent the emergence and spread of drug-resistant bacteria, herein, the kill rate and mutant selection window (MSW) of danofloxacin (DAN) against A. pleuropneumoniae were evaluated. METHODS: For the kill rate study, the minimum inhibitory concentration (MIC) was tested using the micro dilution broth method and time-killing curves of DAN against A. pleuropneumoniae grown in tryptic soy broth (TSB) at a series drug concentrations (from 0 to 64 MIC) were constructed. The relationships between the kill rate and drug concentrations were analyzed using a Sigmoid Emax model during different time periods. For the MSW study, the MIC99 (the lowest concentration that inhibited the growth of the bacteria by ≥ 99%) and mutant prevention concentration (MPC) of DAN against A. pleuropneumoniae were measured using the agar plate method. Then, a peristaltic pump infection model was established to simulate the dynamic changes of DAN concentrations in pig lungs. The changes in number and sensitivity of A. pleuropneumoniae were measured. The relationships between pharmacokinetic/pharmacodynamic parameters and the antibacterial effect were analyzed using the Sigmoid Emax model. RESULTS: In kill rate study, the MIC of DAN against A. pleuropneumoniae was 0.016 µg/mL. According to the kill rate, DAN exhibited concentration-dependent antibacterial activity against A. pleuropneumoniae. A bactericidal effect was observed when the DAN concentration reached 4-8 MIC. The kill rate increased constantly with the increase in DAN concentration, with a maximum value of 3.23 Log10 colony forming units (CFU)/mL/h during the 0-1 h period. When the drug concentration was in the middle part of the MSW, drugresistant bacteria might be induced. Therefore, the dosage should be avoided to produce a mean value of AUC24h/MIC99 (between 31.29 and 62.59 h. The values of AUC24h/MIC99 to achieve bacteriostatic, bactericidal, and eradication effects were 9.46, 25.14, and > 62.59 h, respectively. CONCLUSION: These kill rate and MSW results will provide valuable guidance for the use of DAN to treat A. pleuropneumoniae infections.

Amoxicillin, gemifloxacin and rabeprazole, as first-line Helicobacter pylori therapy in clinical practice: A pilot study.

Success in eradication of H. pylori is decreasing due to increasing resistant strains. In particular, side-effects due to 4-agent treatment multiple drug use are observed and treatment compliance decreases. The aim of this study was to evaluate the efficacy, reliability, and side-effect profile of the combination of amoxicillin and rabeprazole with gemifloxacin, which is a new generation quinolone, in the treatment of H. pylori infection. This study was conducted on 71 naive patients who received H. pylori eradication. All the patients were administered treatment of Amoxicillin (1000 mg twice a day) + Gemifloxacin (320 mg once a day) + rabeprazole (20 mg twice a day) for 7 days. Drug compliance and treatment tolerance were evaluated after finishing the treatment. At 1 month after the end of the treatment, H. pylori eradication was evaluated in all the patients by examining H. pylori antigen in the feces. In the evaluation after treatment, H. pylori eradication was obtained in 63 (88.7%) patients and eradication was not obtained in 8 (11.3%) patients. The treatment was not completed by 2 patients because of side-effects and noncompliance, so after exclusion of these 2 patients, successful H. pylori eradication was obtained in 63 (91.3%) of 69 patients who completed the treatment. Side-effects were seen in a total of 9 (12.7%) patients. Diarrhea, bloating, abdominal pain, and nausea-vomiting were seen in some patients, but no reflux, constipation, skin rash, listlessness-fatigue, headache, dizziness, palpitations, dry mouth, or weight loss was seen in any patient. In regions with high resistance to clarithromycin and metronidazole in particular, the combination of gemifloxacin with amoxicillin and rabeprazole can be considered for use in first-stage treatment as both the efficacy and tolerability are high.

Drug-resistant Mycobacterium tuberculosis among Nepalese patients at a tuberculosis referral center.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB), characterized by isoniazid and rifampicin resistance, is caused by chromosomal mutations that restrict treatment options and complicate tuberculosis management. This study sought to investigate the prevalence of pre-extensively drug-resistant (pre-XDR) and extensively drug-resistant (XDR) tuberculosis, as well as mutation pattern, in Nepalese patients with MDR/rifampicin-resistant (RR)-TB strains. METHODS: A cross-sectional study was conducted on MDR/RR-TB patients at the German Nepal Tuberculosis Project from June 2017 to June 2018. The MTBDRsl line probe assay identified pre-XDR-TB and XDR-TB. Pre-XDR-TB included MDR/RR-TB with resistance to any fluoroquinolone (FLQ), while XDR-TB included MDR/RR-TB with resistance to any FLQ and at least one additional group A drug. Mutation status was determined by comparing bands on reaction zones [gyrA and gyrB for FLQ resistance, rrs for SILD resistance, and eis for low-level kanamycin resistance, according to the GenoType MTBDRsl VER 2.0, Hain Lifescience GmbH, Nehren, Germany definition of pre-XDR and XDR] to the evaluation sheet. SPSS version 17.0 was used for data analysis. RESULTS: Out of a total of 171 patients with MDR/RR-TB, 160 had (93.57%) had MTBC, of whom 57 (35.63%) had pre-XDR-TB and 10 (6.25%) had XDR-TB. Among the pre-XDR-TB strains, 56 (98.25%) were FLQ resistant, while 1 (1.75%) was SLID resistant. The most frequent mutations were found at codons MUT3C (57.14%, 32/56) and MUT1 (23.21%, 13/56) of the gyrA gene. One patient had SLID resistant genotype at the MUT1 codon of the rrs gene (100%, 1/1). XDR-TB mutation bands were mostly detected on MUT1 (30%, 3/10) of the gyrA and rrs, MUT3C (30%, 3/10) of the gyrA, and MUT1 (30%, 3/10) of the rrs. CONCLUSIONS: Pre-XDR-TB had a significantly higher likelihood than XDR-TB, with different specific mutation bands present in gyrA and rrs genes.

Plasmid-Mediated Fluoroquinolone Resistance among Enterobacterales in Africa: Systematic Review.

INTRODUCTION: According to the World Health Organization, antimicrobial resistance (AMR) is a silent global pandemic that plagues everyone. It makes therapy of infectious diseases more difficult and eventually increases morbidity and mortality. AIM: The purpose of this work is to examine existing data on plasmid-mediated quinolone resistance (PMQR), to assess the prevalence of PMQR genes in Enterobacterales, and to determine any knowledge gaps from sub-Saharan Africa. METHODOLOGY: The Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) standard was followed when conducting this systematic review. The main internet databases examined for pertinent publications were PubMed, Google Scholar, and Ajol. A set of qualifying criteria were used to evaluate the qualified articles. Using the eligibility criteria, 56 full-text articles were chosen for screening. RESULT: Thirty-two (32) articles with the majority originating from West and North Africa and only one article reporting a study carried out in Central Africa were selected for this review. Escherichia coli and Ciprofloxacin were the most reported Enterobacterales and Quinolone respectively. The PMQR genes include qnr (qnrA,qnrB, qnrC, qnrD, and qnrS), aac (6') Ib, aac (6') Ib-cr, oqxAB and qepA gene. The most prevalent PMQR gene is the aac (6') Ib-cr gene (32%) followed by qnrS (26%). CONCLUSION: This study highlighted the requirement for an efficient antimicrobial resistance surveillance system in the continent and revealed a significant incidence of PMQR genes.

INTRODUCTION: Selon l'Organisation mondiale de la santé, la résistance aux antimicrobiens (RAM) est une pandémie mondiale silencieuse qui touche tout le monde. Elle rend le traitement des maladies infectieuses plus difficile et finit par augmenter la morbidité et la mortalité. OBJECTIF: L'objectif de ce travail est d'examiner les données existantes sur la résistance plasmidique aux quinolones (PMQR), d'évaluer la prévalence des gènes PMQR chez les Enterobacterales et de déterminer d'éventuelles lacunes de connaissances en Afrique subsaharienne. MÉTHODOLOGIE: La norme Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) a été suivie lors de la réalisation de cette revue systématique. Les principales bases de données Internet examinées pour des publications pertinentes étaient PubMed, Google Scholar et Ajol. Un ensemble de critères d'admissibilité a été utilisé pour évaluer les articles qualifiés. En utilisant les critères d'éligibilité, 56 articles en texte intégral ont été choisis pour le dépistage. RÉSULTAT: Trente-deux (32) articles, dont la majorité provient d'Afrique de l'Ouest et du Nord, et un seul article rapportant une étude menée en Afrique centrale, ont été sélectionnés pour cette revue. Escherichia coli et la ciprofloxacine étaient les Enterobacterales et les quinolones les plus signalées respectivement. Les gènes PMQR comprennent les gènes qnr (qnrA, qnrB, qnrC, qnrD et qnrS), aac (6 ') Ib, aac (6 ') Ib-cr, oqxAB et qepA. Le gène PMQR le plus prévalent est le gène aac (6 ') Ib-cr (32 %), suivi de qnrS (26 %). CONCLUSION: Cette étude a souligné la nécessité d'un système efficace de surveillance de la résistance aux antimicrobiens sur le continen`t et a révélé une incidence significative des gènes PMQR. MOTS-CLÉS: Enterobacterales, Escherichia coli, Quinolone, Ciprofloxacine, PMQR, "aac(6')-Ib", "aac(6')-Ib-cr", "qnr", "qepA", "oqxAB", "résistance aux antibiotiques".

Coexistence of plasmid-mediated quinolone resistance (PMQR) and extended-spectrum beta-lactamase (ESBL) genes among clinical Pseudomonas aeruginosa isolates in Egypt.

BACKGROUND: Data about the prevalence of plasmid-mediated quinolone resistance (PMQR) and extended-spectrum beta-lactamase (ESBL) production in P. aeruginosa compared to the Enterobacteriaceae family is limited. The availability of limited therapeutic options raises alarming concerns about the treatment of multidrug-resistant P. aeruginosa. This study aimed to assess the presence of PMQR and ESBL genes among P. aeruginosa strains. METHODS: Fifty-six P. aeruginosa strains were isolated from 330 patients with different clinical infections. Phenotypically fluoroquinolone-resistant isolates were tested by PCR for the presence of six PMQR genes. Then, blaTEM, blaSHV, and blaCTX-M type ESBL genes were screened to study the co-existence of different resistance determinants. RESULTS: Overall, 22/56 (39.3%) of the studied P. aeruginosa isolates were phenotypically resistant to fluoroquinolones. PMQR-producing P. aeruginosa isolates were identified in 20 isolates (90.9%). The acc(6')-Ib-cr was the most prevalent PMQR gene (77.3%). The qnr genes occurred in 72.7%, with the predominance of the qnrA gene at 54.5%, followed by the qnrS gene at 27.3%, then qnrB and qnrC at 22.7%. The qepA was not detected in any isolate. The acc(6')-Ib-cr was associated with qnr genes in 65% of positive PMQR isolates. Significant differences between the fluoroquinolone-resistant and fluoroquinolone-susceptible isolates in terms of the antibiotic resistance rates of amikacin, imipenem, and cefepime (P value < 0.0001) were found. The ESBL genes were detected in 52% of cephalosporin-resistant P. aeruginosa isolates. The most frequent ESBL gene was blaCTX-M (76.9%), followed by blaTEM (46.2%). No isolates carried the blaSHV gene. The acc(6')-Ib-cr gene showed the highest association with ESBL genes, followed by the qnrA gene. The correlation matrix of the detected PMQR and ESBL genes indicated overall positive correlations. The strongest and most highly significant correlation was between qnrA and acc(6')-Ib-cr (r = 0.602) and between qnrA and blaCTX-M (r = 0.519). CONCLUSION: A high prevalence of PMQR genes among the phenotypic fluoroquinolone-resistant P. aeruginosa isolates was detected, with the co-carriage of different PMQR genes. The most frequent PMQR was the acc(6')-Ib-cr gene. Co-existence between PMQR and ESBL genes was found, with 75% of PMQR-positive isolates carrying at least one ESBL gene. A high and significant correlation between the ESBL and PMQR genes was detected.

Evidence of Helicobacter pylori heterogeneity in human stomachs by susceptibility testing and characterization of mutations in drug-resistant isolates.

Heterogeneity of Helicobacter pylori communities contributes to its pathogenicity and diverse clinical outcomes. We conducted drug-susceptibility tests using four antibiotics, clarithromycin (CLR), amoxicillin (AMX), metronidazole and sitafloxacin, to examine H. pylori population diversity. We also analyzed genes associated with resistance to CLR and AMX. We examined multiple isolates from 42 Japanese patients, including 28 patients in whom primary eradication with CLR and AMX had failed, and 14 treatment-naïve patients. We identified some patients with coexistence of drug resistant- and sensitive-isolates (drug-heteroR/S-patients). More than 60% of patients were drug-heteroR/S to all four drugs, indicating extensive heterogeneity. For the four drugs except AMX, the rates of drug-heteroR/S-patients were higher in treatment-naïve patients than in primary eradication-failure patients. In primary eradication-failure patients, isolates multi-resistant to all four drugs existed among other isolates. In primary eradication-failure drug-heteroR/S-patients, CLR- and AMX-resistant isolates were preferentially distributed to the corpus and antrum with different minimum inhibitory concentrations, respectively. We found two mutations in PBP1A, G591K and A480V, and analyzed these in recombinants to directly demonstrate their association with AMX resistance. Assessment of multiple isolates from different stomach regions will improve accurate assessment of H. pylori colonization status in the stomach.

Spectral characterization, degradation behavior, quenching, and semi-quantification of fluoroquinolone antibiotics in the antibiotic-humic mixture using fluorescence spectroscopy.

Antibiotics, one of the significant emerging contaminants, are intensifying their continual spread out into the environment and affecting human health and the ecosystem in the developing country Bangladesh. This study characterizes widely used fluoroquinolone (FQ) antibiotics, formulates the method to spectrally distinguish them from ubiquitous, and important reactive, adsorbent, and altering catalytic macromolecule humic substances (HS), and further quantifies them using fluorescence spectroscopy. The presence of identical fluorophore at Excitation/Emission = 225-230/285-295 nm wavelength, possession of fluorescence spectra at short emission wavelength (<350 nm) during 275 nm excitation, different emission maxima, and various fluorescing components in antibiotics identified through three-dimensional excitation-emission matrix (EEM) and parallel factor analysis (PARAFAC) models distinguished them from the humic substance as well as from each other. Stern-Volmer equation and its modified version were applied to identify quenching and binding capability, and fluorescence intensity quenching rate of antibiotics and humic in their mixture. Unlike poor and inconsistent quenching mechanisms of humic, FQ antibiotics reduced HS intensity throughout the entire photo-irradiation experiment affirming the functioning of the stable quenching methods. Static quenching of fluorophores was identified from the redshift of excited wavelength on the electronic ground state. Temperature differences during daylight and dark conditions played contrasting roles during the fluorescence quenching of FQ. Unique spectral response at emission wavelength < 350 nm during 275 nm excitation in FQ was considered as its least intensity in the antibiotic-humic mixture and was also used to formulate distinct spectral pattern of each FQ antibiotic. The study also identified the traces of FQ antibiotics with various intensities at different lakes in Bangladesh.

Gyrase and Topoisomerase IV: Recycling Old Targets for New Antibacterials to Combat Fluoroquinolone Resistance.

Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone antibacterials. These drugs act by stabilizing gyrase/topoisomerase IV-generated DNA strand breaks and by robbing the cell of the catalytic activities of these essential enzymes. Since their clinical approval in the mid-1980s, fluoroquinolones have been used to treat a broad spectrum of infectious diseases and are listed among the five "highest priority" critically important antimicrobial classes by the World Health Organization. Unfortunately, the widespread use of fluoroquinolones has been accompanied by a rise in target-mediated resistance caused by specific mutations in gyrase and topoisomerase IV, which has curtailed the medical efficacy of this drug class. As a result, efforts are underway to identify novel antibacterials that target the bacterial type II topoisomerases. Several new classes of gyrase/topoisomerase IV-targeted antibacterials have emerged, including novel bacterial topoisomerase inhibitors, Mycobacterium tuberculosis gyrase inhibitors, triazaacenaphthylenes, spiropyrimidinetriones, and thiophenes. Phase III clinical trials that utilized two members of these classes, gepotidacin (triazaacenaphthylene) and zoliflodacin (spiropyrimidinetrione), have been completed with positive outcomes, underscoring the potential of these compounds to become the first new classes of antibacterials introduced into the clinic in decades. Because gyrase and topoisomerase IV are validated targets for established and emerging antibacterials, this review will describe the catalytic mechanism and cellular activities of the bacterial type II topoisomerases, their interactions with fluoroquinolones, the mechanism of target-mediated fluoroquinolone resistance, and the actions of novel antibacterials against wild-type and fluoroquinolone-resistant gyrase and topoisomerase IV.

Fate and removal of fluoroquinolone antibiotics in mesocosmic wetlands: Impact on wetland performance, resistance genes and microbial communities.

The fate of fluoroquinolone antibiotics norfloxacin and ofloxacin were investigated in mesocosmic wetlands, along with their effects on nutrients removal, antibiotic resistance genes (ARGs) and epiphytic microbial communities on Hydrilla verticillate using bionic plants as control groups. Approximately 99% of norfloxacin and ofloxacin were removed from overlaying water, and H. verticillate inhibited fluoroquinolones accumulation in surface sediments compared to bionic plants. Partial least squares path modeling showed that antibiotics significantly inhibited the nutrient removal capacity (0.55) but had no direct effect on plant physiology. Ofloxacin impaired wetland performance more strongly than norfloxacin and more impacted the primary microbial phyla, whereas substrates played the most decisive role on microbial diversities. High antibiotics concentration shifted the most dominant phyla from Proteobacteria to Bacteroidetes and inhibited the Xenobiotics biodegradation function, contributing to the aggravation in wetland performance. Dechloromonas and Pseudomonas were regarded as the key microorganisms for antibiotics degradation. Co-occurrence network analysis excavated that microorganisms degrade antibiotics mainly through co-metabolism, and more complexity and facilitation/reciprocity between microbes attached to submerged plants compared to bionic plants. Furthermore, environmental factors influenced ARGs mainly by altering the community dynamics of differential bacteria. This study offers new insights into antibiotic removal and regulation of ARGs accumulation in wetlands with submerged macrophyte.

Expression of norA, norB and norC efflux pump genes mediating fluoroquinolones resistance in MRSA isolates.

INTRODUCTION: Although fluoroquinolones are used to treat methicillin-resistant Staphylococcus aureus (MRSA)-induced infections, acquisition of antibiotic resistance by bacteria has impaired their clinical relevance. We aimed to evaluate the frequency of norA, norB, and norC efflux pump genes-mediating fluoroquinolones resistance and measure their expression levels in MRSA isolates. METHODOLOGY: 126 S. aureus isolates were collected from different clinical samples of adult hospitalized patients and identified by conventional microbiological methods. MRSA was diagnosed by cefoxitin disc diffusion method and minimum inhibitory concentration (MIC) of ciprofloxacin by broth microdilution method. The expression levels of efflux pump genes were measured by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: 80 (63.5%) MRSA isolates were identified and showed high level of resistance to erythromycin (80%), gentamicin (75%), clindamycin (65%) and ciprofloxacin (60 %). norA, norB and norC were detected in 75%, 35% and 55% of the MRSA isolates respectively. norC was the most commonly overexpressed gene measured by qRT-PCR, occurring in 40% of MRSA isolates, followed by norA (35%) and norB (30%). The expression of these genes was significantly higher in ciprofloxacin-resistant than quantitative real-time PCR ciprofloxacin-sensitive MRSA isolates. CONCLUSIONS: This study showed high prevalence and overexpression of efflux pump genes among MRSA isolates which indicates the significant role of these genes in the development of multidrug resistance against antibiotics including fluoroquinolones.

Physicochemical properties as a function of lomefloxacin biological activity.

OBJECTIVE: Aim: The goal is to discover QSAR of Lomefloxacin as antibacterial activity. PATIENTS AND METHODS: Materials and Methods: A number of lomefloxacins analogs activities were studied by program Windows Chem SW. The analogues were obtained and energy minimization was carried out through Molecular Modeling Program, the calculations were performed using General Atomic and Molecular Electronic Structure System (GAMESS) software. RESULTS: Results: There were six descriptions (N-quinoline more (-) ev charge, Kinetic Energy, Potential Energy, Log p, Log S, F6 charge) results have highly compatible of physicochemical properties with lomefloxacin analogs activities. It can be used to estimate the activities depending on QSAR equation of lomefloxacin analogs. CONCLUSION: Conclusions: The parameters used for calculation were depending on the quantum chemical was employed in deriving from computational study of properties and can used to predict the activities of certain analogs of Lomefloxacins as antibacterial compounds.

Potential acetylcholinesterase inhibitors to treat Alzheimer's disease.

OBJECTIVE: Alzheimer's disease (AD) is identified by neuropathological symptoms, and there is now no effective treatment for the condition. A lack of the brain neurotransmitter acetylcholine has been related to the etiology of Alzheimer's disease. Acetylcholinesterase is an enzyme that breaks down acetylcholine to an inactive form and causes the death of cholinergic neurons. Conventional treatments were used but had less effectiveness. Therefore, there is a crucial need to identify alternative compounds with potential anti-cholinesterase agents and minimal undesirable effects. MATERIALS AND METHODS: Fluoroquinolones and benzimidazole-benzothiazole derivatives offer antimicrobial, anti-inflammatory, anti-oxidant, anti-diabetic, and anti-Alzheimer activities. To enhance the chemical portfolio of cholinesterase inhibitors, a variety of fluoroquinolones and benzimidazole-benzothiazole compounds were evaluated against acetylcholinesterase (AChE) butyrylcholinesterase (BChE) enzymes. For this purpose, molecular docking and adsorption, distribution, metabolism, excretion, and toxicology ADMET models were used for in-silico studies for both AChE and BChE enzymes to investigate possible binding mechanisms and drug-likeness of the compounds. The inhibitory effect of docked heterocyclic compounds was also verified in vitro against AChE and BChE enzymes. Fluoroquinolones (Z, Z3, Z4, Z6, Z8, Z12, Z15, and Z9) and benzimidazole-benzothiazole compounds (TBIS-16, TBAF-1 to 9) passed through the AChE inhibition assay and their IC50 values were calculated. RESULTS: The compound 1-ethyl-6-fluoro-7-(4-(2-(4-nitrophenylamino)-2-oxoethyl)piperazin-1-yl) -4-oxo-1,4 di-hydroquinoline-3-carboxylic acid and 2-((1H-benzo[d]imidazol-2-yl)methyl)-N'-(3-bromobenzyl)-4-hydroxy-2H-thiochromene-3-carbohydrazide 1,1-dioxide (Z-9 and TBAF-6) showed the lowest IC50 values against AChE/BChE (0.37±0.02/2.93±0.03 µM and 0.638±0.001/1.31±0.01 µM, respectively) than the standard drug, donepezil (3.9±0.01/4.9±0.05 µM). During the in-vivo investigation, behavioral trials were performed to analyze the neuroprotective impact of Z-9 and TBAF-6 compounds on AD mouse models. The groups treated with Z-9 and TBAF-6 compounds had better cognitive behavior than the standard drug. CONCLUSIONS: This study found that Z-9 (Fluoroquinolones) and TBAF-6 (benzimidazole-benzothiazole) compounds improve behavioral and biochemical parameters, thus treating neurodegenerative disorders effectively.

Change in Tissue Microbiome and Related Human Beta Defensin Levels Induced by Antibiotic Use in Bladder Carcinoma.

It is now generally accepted that the success of antitumor therapy can be impaired by concurrent antibiotic therapy, the presence of certain bacteria, and elevated defensin levels around the tumor tissue. The aim of our current investigation was to identify the underlying changes in microbiome and defensin levels in the tumor tissue induced by different antibiotics, as well as the duration of this modification. The microbiome of the tumor tissues was significantly different from that of healthy volunteers. Comparing only the tumor samples, no significant difference was confirmed between the untreated group and the group treated with antibiotics more than 3 months earlier. However, antibiotic treatment within 3 months of analysis resulted in a significantly modified microbiome composition. Irrespective of whether Fosfomycin, Fluoroquinolone or Beta-lactam treatment was used, the abundance of Bacteroides decreased, and Staphylococcus abundance increased. Large amounts of the genus Acinetobacter were observed in the Fluoroquinolone-treated group. Regardless of the antibiotic treatment, hBD1 expression of the tumor cells consistently doubled. The increase in hBD2 and hBD3 expression was the highest in the Beta-lactam treated group. Apparently, antibiotic treatment within 3 months of sample analysis induced microbiome changes and defensin expression levels, depending on the identity of the applied antibiotic.

Detection of Macrolide and/or Fluoroquinolone Resistance Genes in Mycoplasma genitalium Strains Isolated from Men in the Northwest Region of Croatia in 2018-2023.

Mycoplasma genitalium (M. genitalium) poses a significant public health challenge due to its association with non-gonococcal urethritis (particularly in men) and antimicrobial resistance. However, despite the prevalence of M. genitalium infections and the rise in resistance rates, routine testing and surveillance remain limited. This is the first study from Croatia that aimed to assess the prevalence and trends of resistance in M. genitalium strains isolated from male individuals by detecting macrolide and fluoroquinolone resistance genes. The study also aimed to explore the factors associated with resistance and changes in resistance patterns over time. Urine samples collected from male individuals in the Zagreb County and northwest region of Croatia between 2018 and 2023 were tested for M. genitalium with the use of molecular methods. Positive samples were subjected to DNA extraction and multiplex tandem polymerase chain reaction (MT-PCR) targeting genetic mutations associated with macrolide (23S rRNA gene) and fluoroquinolone (parC gene) resistance. Of the 8073 urine samples tested from 6480 male individuals (and following the exclusion of repeated specimens), we found that the prevalence of M. genitalium infection was 2.2%. Macrolide resistance was observed in 60.4% of strains, while fluoroquinolone resistance was found in 19.2%. Co-resistance to both antibiotics was present in 18.2% of cases. A statistically significant increase in fluoroquinolone resistance was noted over the study period (p = 0.010), but this was not evident for azithromycin resistance (p = 0.165). There were no statistically significant differences in resistance patterns between age groups, whereas re-testing of patients revealed dynamic changes in resistance profiles over time. The high burden of macrolide resistance and increasing fluoroquinolone resistance underscore the urgent need for comprehensive resistance testing and surveillance programs. The implementation of resistance-guided treatment strategies, along with enhanced access to molecular diagnostics, is pivotal for effectively managing M. genitalium infections.

Patterns and profiles of drug resistance-conferring mutations in Mycobacterium tuberculosis genotypes isolated from tuberculosis-suspected attendees of spiritual holy water sites in Northwest Ethiopia.

Purpose: This study examined the patterns and frequency of genetic changes responsible for resistance to first-line (rifampicin and isoniazid), fluoroquinolones, and second-line injectable drugs in drug-resistant Mycobacterium tuberculosis (MTB) isolated from culture-positive pulmonary tuberculosis (PTB) symptomatic attendees of spiritual holy water sites (HWSs) in the Amhara region. Patients and methods: From June 2019 to March 2020, a cross-sectional study was carried out. A total of 122 culture-positive MTB isolates from PTB-suspected attendees of HWSs in the Amhara region were evaluated for their drug resistance profiles, and characterized gene mutations conferring resistance to rifampicin (RIF), isoniazid (INH), fluoroquinolones (FLQs), and second-line injectable drugs (SLIDs) using GenoType®MTBDRplus VER2.0 and GenoType®MTBDRsl VER2.0. Drug-resistant MTB isolates were Spoligotyped following the manufacturer's protocol. Results: Genetic changes (mutations) responsible for resistance to RIF, INH, and FLQs were identified in 15/122 (12.3%), 20/122 (16.4%), and 5/20 (25%) of MTB isolates, respectively. In RIF-resistant, rpoB/Ser531Lue (n = 12, 80%) was most frequent followed by His526Tyr (6.7%). Amongst INH-resistant isolates, katG/Ser315Thr1 (n = 19, 95%) was the most frequent. Of 15 MDR-TB, the majority (n = 12, 80%) isolates had mutations at both rpoB/Ser531Leu and katG/Ser315Thr1. All 20 INH and/or RIF-resistant isolates were tested with the MTBDRsl VER 2.0, yielding 5 FLQs-resistant isolates with gene mutations at rpoB/Ser531Lue, katG/Ser315Thr1, and gyrA/Asp94Ala genes. Of 20 Spoligotyped drug-resistant MTB isolates, the majority (n = 11, 55%) and 6 (30%) were SIT149/T3-ETH and SIT21/CAS1-Kili sublineages, respectively; and they were any INH-resistant (mono-hetero/multi-). Of 15 RIF-resistant (RR/MDR-TB) isolates, 7 were SIT149/T3-ETH, while 6 were SIT21/CAS1-Kili sublineages. FLQ resistance was detected in four SIT21/CAS1-Kili lineages. Conclusion: In the current study, the most common gene mutations responsible for resistance to INH, RIF, and FLQs were identified. SIT149/T3-ETH and SIT21/CAS1-Kili constitute the majority of drug-resistant TB (DR-TB) isolates. To further understand the complete spectrum of genetic changes/mutations and related genotypes, a sequencing technology is warranted.

Differential impacts of DNA repair machinery on fluoroquinolone persisters with different chromosome abundances.

DNA repair machinery has been found to be indispensable for fluoroquinolone (FQ) persistence of Escherichia coli. Previously, we found that cells harboring two copies of the chromosome (2Chr) in stationary-phase cultures were more likely to yield FQ persisters than those with one copy of the chromosome (1Chr). Furthermore, we found that RecA and RecB were required to observe that difference, and that loss of either more significantly impacted 2Chr persisters than 1Chr persisters. To better understand the survival mechanisms of persisters with different chromosome abundances, we examined their dependencies on different DNA repair proteins. Here, we show that lexA3 and ∆recN negatively impact the abundances of 2Chr persisters to FQs, without significant impacts on 1Chr persisters. In comparison, ∆xseA, ∆xseB, and ∆uvrD preferentially depress 1Chr persistence to levels that were near the limit of detection. Collectively, these data show that the DNA repair mechanisms used by persisters vary based on chromosome number, and suggest that efforts to eradicate FQ persisters will likely have to take heterogeneity in single-cell chromosome abundance into consideration. IMPORTANCE: Persisters are rare phenotypic variants in isogenic populations that survive antibiotic treatments that kill the other cells present. Evidence has accumulated that supports a role for persisters in chronic and recurrent infections. Here, we explore how an under-appreciated phenotypic variable, chromosome copy number (#Chr), influences the DNA repair systems persisters use to survive fluoroquinolone treatments. We found that #Chr significantly biases the DNA repair systems used by persisters, which suggests that #Chr heterogeneity should be considered when devising strategies to eradicate these troublesome bacterial variants.

Characterization and removal mechanism of fluoroquinolone-bioremediation by fungus Cladosporium cladosporioides 11 isolated from aquacultural sediments.

Antibiotics have been widely detected in aquatic environments, and fungal biotransformation receives considerable attention for antibiotic bioremediation. Here, a fungus designated Cladosporium cladosporioides 11 (CC11) with effective capacity to biotransform fluoroquinolones was isolated from aquaculture pond sediments. Enrofloxacin (ENR), ciprofloxacin (CIP) and ofloxacin (OFL) were considerably abated by CC11, and the antibacterial activities of the fluoroquinolones reduced significantly after CC11 treatment. Transcriptome analysis showed the removal of ENR, CIP and OFL by CC11 is a process of enzymatic degradation and biosorption which consists well with ligninolytic enzyme activities and sorption experiments under the same conditions. Additionally, CC11 significantly removed ENR in zebrafish culture water and reduced the residue of ENR in zebrafish. All these results evidenced the potential of CC11 as a novel environmentally friendly process for the removal of fluoroquinolones from aqueous systems and reduce fluoroquinolone residues in aquatic organisms.

Safety of fluoroquinolones / Seguridad de las fluoroquinolonas

Fluoroquinolones (FQs) are one of the most commonly prescribed classes of antibiotics. Although they were initially well tolerated in randomized clinical trials, subsequent epidemiological studies have reported an increased risk of threatening, severe, long-lasting, disabling and irreversible adverse effects (AEs), related to neurotoxicity and collagen degradation, such as tendonitis, Achilles tendon rupture, aortic aneurysm, and retinal detachment. This article reviews the main potentially threatening AEs, the alarms issued by regulatory agencies and therapeutic alternatives. (AU)

Las fluoroquinolonas son una de las clases de antibióticos más prescritas. Aunque inicialmente fueron bien toleradas en ensayos clínicos aleatorizados, estudios epidemiológicos posteriores han informado de un mayor riesgo de efectos adversos efectos adversos amenazantes, graves, duraderos, incapacitantes e irreversibles, relacionados con la neurotoxicidad y la degradación del colágeno, como tendinitis, rotura del tendón de Aquiles, aneurisma aórtico y desprendimiento de retina. Este artículo repasa los principales efectos adversos potencialmente amenazadores, las alarmas emitidas por las agencias reguladoras y las alternativas terapéuticas. (AU)