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Communications Biology Jun 2024Antimicrobial resistance (AMR) poses a serious threat to the clinical management of typhoid fever. AMR in Salmonella Typhi (S. Typhi) is commonly associated with the H58...
Antimicrobial resistance (AMR) poses a serious threat to the clinical management of typhoid fever. AMR in Salmonella Typhi (S. Typhi) is commonly associated with the H58 lineage, a lineage that arose comparatively recently before becoming globally disseminated. To better understand when and how H58 emerged and became dominant, we performed detailed phylogenetic analyses on contemporary genome sequences from S. Typhi isolated in the period spanning the emergence. Our dataset, which contains the earliest described H58 S. Typhi organism, indicates that ancestral H58 organisms were already multi-drug resistant (MDR). These organisms emerged spontaneously in India in 1987 and became radially distributed throughout South Asia and then globally in the ensuing years. These early organisms were associated with a single long branch, possessing mutations associated with increased bile tolerance, suggesting that the first H58 organism was generated during chronic carriage. The subsequent use of fluoroquinolones led to several independent mutations in gyrA. The ability of H58 to acquire and maintain AMR genes continues to pose a threat, as extensively drug-resistant (XDR; MDR plus resistance to ciprofloxacin and third generation cephalosporins) variants, have emerged recently in this lineage. Understanding where and how H58 S. Typhi originated and became successful is key to understand how AMR drives successful lineages of bacterial pathogens. Additionally, these data can inform optimal targeting of typhoid conjugate vaccines (TCVs) for reducing the potential for emergence and the impact of new drug-resistant variants. Emphasis should also be placed upon the prospective identification and treatment of chronic carriers to prevent the emergence of new drug resistant variants with the ability to spread efficiently.
Topics: Salmonella typhi; Typhoid Fever; Phylogeny; Humans; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Haplotypes; Mutation; Genome, Bacterial
PubMed: 38942806
DOI: 10.1038/s42003-024-06451-8 -
Scientific Reports Jun 2024Methicillin-resistant Staphylococcus (MRS) has been associated with neonatal infections, with colonization of the anovaginal tract being the main source of vertical...
Methicillin-resistant Staphylococcus (MRS) has been associated with neonatal infections, with colonization of the anovaginal tract being the main source of vertical transmission. The COVID-19 pandemic has altered the frequency of antibiotic usage, potentially contributing to changes in the dynamics of bacterial agents colonizing humans. Here we determined MRS colonization rates among pregnant individuals attending a single maternity in Rio de Janeiro, Brazil before (January 2019-March 2020) and during (May 2020-March 2021) the COVID-19 pandemic. Anovaginal samples (n = 806 [521 samples before and 285 during the pandemic]) were streaked onto chromogenic media. Colonies were identified by MALDI-TOF MS. Detection of mecA gene and SCCmec typing were assessed by PCR and antimicrobial susceptibility testing was done according to CLSI guidelines. After the onset of the pandemic, MRS colonization rates increased significantly (p < 0.05) from 8.6% (45) to 54.7% (156). Overall, 215 (26.6%) MRS isolates were detected, of which S. haemolyticus was the most prevalent species (MRSH, 84.2%; 181 isolates). SCCmec type V was the most frequent among MRS (63.3%; 136), and 31.6% (68) of MRS strains had a non-typeable SCCmec, due to new combinations of ccr and mecA complexes. Among MRS strains, 41.9% (90) were resistant to at least 3 different classes of antimicrobial agents, and 60% (54) of them were S. haemolyticus harboring SCCmec V. MRS colonization rates and the emergence of multidrug-resistant variants detected in this study indicate the need for continuing surveillance of this important pathogen within maternal and child populations.
Topics: Humans; Female; Pregnancy; COVID-19; Staphylococcal Infections; Methicillin-Resistant Staphylococcus aureus; Adult; Brazil; Pregnancy Complications, Infectious; Anti-Bacterial Agents; SARS-CoV-2; Microbial Sensitivity Tests; Pandemics; Vagina
PubMed: 38942787
DOI: 10.1038/s41598-024-64422-9 -
Nature Communications Jun 2024In a pivotal trial (EPIC-HR), a 5-day course of oral ritonavir-boosted nirmatrelvir, given early during symptomatic SARS-CoV-2 infection (within three days of symptoms...
In a pivotal trial (EPIC-HR), a 5-day course of oral ritonavir-boosted nirmatrelvir, given early during symptomatic SARS-CoV-2 infection (within three days of symptoms onset), decreased hospitalization and death by 89.1% and nasal viral load by 0.87 log relative to placebo in high-risk individuals. Yet, nirmatrelvir/ritonavir failed as post-exposure prophylaxis in a trial, and frequent viral rebound has been observed in subsequent cohorts. We develop a mathematical model capturing viral-immune dynamics and nirmatrelvir pharmacokinetics that recapitulates viral loads from this and another clinical trial (PLATCOV). Our results suggest that nirmatrelvir's in vivo potency is significantly lower than in vitro assays predict. According to our model, a maximally potent agent would reduce the viral load by approximately 3.5 logs relative to placebo at 5 days. The model identifies that earlier initiation and shorter treatment duration are key predictors of post-treatment rebound. Extension of treatment to 10 days for Omicron variant infection in vaccinated individuals, rather than increasing dose or dosing frequency, is predicted to lower the incidence of viral rebound significantly.
Topics: Humans; SARS-CoV-2; Ritonavir; COVID-19 Drug Treatment; COVID-19; Viral Load; Antiviral Agents; Indazoles; Models, Theoretical; Post-Exposure Prophylaxis; Lactams; Leucine; Nitriles; Proline
PubMed: 38942778
DOI: 10.1038/s41467-024-49458-9 -
Progress in Molecular Biology and... 2024Repurposing pharmaceuticals is a technique used to find new, alternate clinical applications for approved drug molecules. It may include altering the drug formulation,... (Review)
Review
Repurposing pharmaceuticals is a technique used to find new, alternate clinical applications for approved drug molecules. It may include altering the drug formulation, route of administration, dose or the dosage regimen. The process of repurposing medicines starts with screening libraries of previously approved drugs for the targeted disease condition. If after an the initial in silico, in vitro or in vivo experimentation, the molecule has been found to be active against a particular target, the molecule is considered as a good candidate for clinical trials. As the safety profile of such molecules is available from the previous data, significant time and resources are saved. These advantages of drug repurposing approach make it especially helpful for finding treatments for rapidly evolving conditions including bacterial infections. An ever-increasing incidence of antimicrobial resistance, owing to the mutations in bacterial genome, leads to therapeutic failure of many approved antibiotics. Repurposing the approved drug molecules for use as antibiotics can provide an effective means for the combating life-threatening bacterial diseases. A number of drugs have been considered for drug repurposing against bacterial infections. These include, but are not limited to, Auranofin, Closantel, and Toremifene that have been repurposed for various infections. In addition, the reallocation of route of administration, redefining dosage regimen and reformulation of dosage forms have also been carried out for repurposing purpose. The current chapter addresses the drug discovery and development process with relevance to repurposing against bacterial infections.
Topics: Drug Repositioning; Humans; Bacterial Infections; Animals; Anti-Bacterial Agents
PubMed: 38942533
DOI: 10.1016/bs.pmbts.2024.03.031 -
Nature Chemical Biology Jul 2024Keratinicyclins and keratinimicins are recently discovered glycopeptide antibiotics. Keratinimicins show broad-spectrum activity against Gram-positive bacteria, while...
Keratinicyclins and keratinimicins are recently discovered glycopeptide antibiotics. Keratinimicins show broad-spectrum activity against Gram-positive bacteria, while keratinicyclins form a new chemotype by virtue of an unusual oxazolidinone moiety and exhibit specific antibiosis against Clostridioides difficile. Here we report the mechanism of action of keratinicyclin B (KCB). We find that steric constraints preclude KCB from binding peptidoglycan termini. Instead, KCB inhibits C. difficile growth by binding wall teichoic acids (WTAs) and interfering with cell wall remodeling. A computational model, guided by biochemical studies, provides an image of the interaction of KCB with C. difficile WTAs and shows that the same H-bonding framework used by glycopeptide antibiotics to bind peptidoglycan termini is used by KCB for interacting with WTAs. Analysis of KCB in combination with vancomycin (VAN) shows highly synergistic and specific antimicrobial activity, and that nanomolar combinations of the two drugs are sufficient for complete growth inhibition of C. difficile, while leaving common commensal strains unaffected.
Topics: Clostridioides difficile; Anti-Bacterial Agents; Microbial Sensitivity Tests; Vancomycin; Cell Wall; Teichoic Acids; Peptidoglycan; Drug Therapy, Combination; Peptides, Cyclic; Lipopeptides
PubMed: 38942968
DOI: 10.1038/s41589-024-01651-z -
Environmental Monitoring and Assessment Jun 2024Solar Fenton is an important and extensively used advanced oxidation process (AOP) to degrade pharmaceutical pollutants. The objective of this study was to evaluate the...
Solar Fenton is an important and extensively used advanced oxidation process (AOP) to degrade pharmaceutical pollutants. The objective of this study was to evaluate the performance of simultaneous degradation of the mixed pollutants (amoxicillin, acetaminophen, and ciprofloxacin) for an aqueous solution using the solar Fenton process. Operating parameters such as pH, iron doses, HO doses, pollutant concentrations, and time were studied. From the experimental results, the ideal conditions were obtained for the removal of mixed pollutants such as pH 3, Fe 0.04 mM, HO 4 mM, the concentration of the mixed pollutants 5 mg/L, solar radiation 400 W/m, and time 10 min, respectively. The pseudo-first-order kinetics were utilized to investigate the degradation efficacy of the mixed pollutants. The result of the study indicates that the degradation efficiency was > 99% for the mixed pollutants. A maximum of 63% mineralization was observed, and hydroxyl radical scavenger effects were studied. The best optimal conditions were applied to assess the spiked wastewater (municipal wastewater (MWW) and hospital wastewater (HWW)). The highest elimination rates for AMX, ACET, and CIP were observed as 65%, 89%, and 85% for MWW and 76%, 92%, and 80% for HWW, respectively. The degraded by-products were detected by LC-ESI-MS in the water matrix (aqueous solution and spiked wastewater), and ECOSAR analysis was performed for the transformed products. The study concluded that the solar Fenton technique is promising and effective for the removal of mixed pollutants from the water matrix.
Topics: Water Pollutants, Chemical; Hydrogen Peroxide; Kinetics; Iron; Waste Disposal, Fluid; Sunlight; Wastewater; Oxidation-Reduction; Ciprofloxacin; Acetaminophen; Amoxicillin
PubMed: 38942963
DOI: 10.1007/s10661-024-12837-2 -
Nature Communications Jun 2024Tigecycline is widely used for treating complicated bacterial infections for which there are no effective drugs. It inhibits bacterial protein translation by blocking...
Tigecycline is widely used for treating complicated bacterial infections for which there are no effective drugs. It inhibits bacterial protein translation by blocking the ribosomal A-site. However, even though it is also cytotoxic for human cells, the molecular mechanism of its inhibition remains unclear. Here, we present cryo-EM structures of tigecycline-bound human mitochondrial 55S, 39S, cytoplasmic 80S and yeast cytoplasmic 80S ribosomes. We find that at clinically relevant concentrations, tigecycline effectively targets human 55S mitoribosomes, potentially, by hindering A-site tRNA accommodation and by blocking the peptidyl transfer center. In contrast, tigecycline does not bind to human 80S ribosomes under physiological concentrations. However, at high tigecycline concentrations, in addition to blocking the A-site, both human and yeast 80S ribosomes bind tigecycline at another conserved binding site restricting the movement of the L1 stalk. In conclusion, the observed distinct binding properties of tigecycline may guide new pathways for drug design and therapy.
Topics: Tigecycline; Cryoelectron Microscopy; Humans; Ribosomes; Anti-Bacterial Agents; Binding Sites; Saccharomyces cerevisiae; Protein Biosynthesis; Mitochondrial Ribosomes; Models, Molecular; RNA, Transfer
PubMed: 38942792
DOI: 10.1038/s41467-024-49797-7 -
Medicine Jun 2024Surgical site infection (SSI) after posterior open lumbar fusion (POLF) is a major concern for both surgeons and patients. We sought to explore whether local application... (Observational Study)
Observational Study
Surgical site infection (SSI) after posterior open lumbar fusion (POLF) is a major concern for both surgeons and patients. We sought to explore whether local application of vancomycin could decrease the rate of SSI. We reviewed the clinical data of patients who underwent POLF between June 2015 and June 2022 at 3 spinal centers. Patients were divided into those who received local vancomycin (vancomycin group) and those who did not (non-vancomycin group). The SSI rates at 12 months postoperatively were compared between the 2 groups. Although a trend toward a lower infection rate was observed in the vancomycin group than in the non-vancomycin group; the difference was not statistically significant (3.6% vs 5.5%, P = .121). However, we found that the postoperative SSI rate was significantly lower in the vancomycin group than in the non-vancomycin group (4.9% vs 11.4%, P = .041) in patients ≥ 2 fused segments, while there was no significant difference in postoperative SSI rate in patients with single fusion segment (3.1% vs 3.6%, P = .706). The logistic regression analysis indicated that the SSI rate in the non-vancomycin group was approximately 2.498 times higher than that in the vancomycin group (P = .048, odds ratio: 2.498, 95% confidence interval: 1.011-6.617) in patients with ≥2 fused segments. In SSI patients with confirmed pathogens, the SSI rate of Gram-negative bacteria in the vancomycin group was significantly higher than that in the non-vancomycin group (10/14 [71.4%] vs 5/22 [31.8%]), whereas the SSI rate of Gram-positive bacteria in the vancomycin group was significantly lower than that in the non-vancomycin group (4/14 [28.6%] vs 15/22 [68.2%]). Local administration of vancomycin is recommended in patients with ≥2 fused segments as it may facilitate to reduce the postoperative rate of SSI after POLF. Additionally, the local use of vancomycin can decrease the Gram-positive bacterial infections but is not effective against Gram-negative infections, which indirectly leads to an increase in the proportion of Gram-negative infections in SSI patients with confirmed pathogens.
Topics: Humans; Vancomycin; Surgical Wound Infection; Spinal Fusion; Retrospective Studies; Male; Female; Middle Aged; Anti-Bacterial Agents; Aged; Lumbar Vertebrae; Adult
PubMed: 38941406
DOI: 10.1097/MD.0000000000038664 -
PloS One 2024A growing increase in the number of serious infections caused by multidrug resistant bacteria (MDR) is challenging our society. Despite efforts to discover novel...
A growing increase in the number of serious infections caused by multidrug resistant bacteria (MDR) is challenging our society. Despite efforts to discover novel therapeutic options, few antibiotics targeting MDR have been approved by the Food and Drug Administration (FDA). Lactic acid bacteria have emerged as a promising therapeutic alternative due to their demonstrated ability to combat MDR pathogens in vitro. Our previous co-culture studies showed Lacticaseibacillus rhamnosus CRL 2244 as having a potent killing effect against carbapenem-resistant Acinetobacter baumannii (CRAB) strains. Here we report that cell-free conditioned media (CFCM) samples obtained from Lcb. rhamnosus CRL 2244 cultures incubated at different times display antimicrobial activity against 43 different pathogens, including CRAB, methicillin-resistant Staphylococcus aureus (MRSA) and carbapenemase Klebsiella pneumoniae (KPC)-positive strains. Furthermore, transwell and ultrafiltration analyses together with physical and chemical/biochemical tests showed that Lcb. rhamnosus CRL 2244 secretes a <3 kDa metabolite(s) whose antimicrobial activity is not significantly impaired by mild changes in pH, temperature and various enzymatic treatments. Furthermore, sensitivity and time-kill assays showed that the bactericidal activity of the Lcb. rhamnosus CRL 2244 metabolite(s) enhances the activity of some current FDA approved antibiotics. We hypothesize that this observation could be due to the effects of Lcb. rhamnosus CRL 2244 metabolite(s) on cell morphology and the enhanced transcriptional expression of genes coding for the phenylacetate (PAA) and histidine catabolic Hut pathways, metal acquisition and biofilm formation, all of which are associated with bacterial virulence. Interestingly, the extracellular presence of Lcb. rhamnosus CRL 2244 induced the transcription of the gene coding for the CidA/LgrA protein, which is involved in programmed cell death in some bacteria. Overall, the findings presented in this report underscore the promising potential of the compound(s) released by Lcb. rhamnosus CRL2244 as an alternative and/or complementary option to treat infections caused by A. baumannii as well as other MDR bacterial pathogens.
Topics: Lacticaseibacillus rhamnosus; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Acinetobacter baumannii; Drug Synergism; Methicillin-Resistant Staphylococcus aureus; Culture Media, Conditioned; Bacterial Proteins
PubMed: 38941324
DOI: 10.1371/journal.pone.0306273 -
The American Journal of Case Reports Jun 2024BACKGROUND Parinaud oculoglandular syndrome is a unilateral granulomatous palpebral conjunctivitis associated with preauricular, submandibular, and cervical...
BACKGROUND Parinaud oculoglandular syndrome is a unilateral granulomatous palpebral conjunctivitis associated with preauricular, submandibular, and cervical lymphadenopathies. Several infectious diseases can cause Parinaud oculoglandular syndrome, usually with a conjunctival entry. The most common underlying pathology is cat scratch disease, followed by the oculoglandular form of tularemia. Diagnosis is usually a serious challenge as these infections are themselves rare. On the other hand, Parinaud oculoglandular syndrome may be a rare manifestation of more common disorders (eg, tuberculosis, syphilis, mumps, herpes simplex and Epstein-Barr virus, adenovirus, Rickettsia, Sporothrix, Chlamydia infections). CASE REPORT We present the case of a 66-year-old man with granulomatous conjunctivitis and ipsilateral preauricular, submandibular, and upper cervical lymphadenopathies following a superficial corneal injury. Although the systematic amoxicillin/clavulanic acid and metronidazole antibiotic therapy started immediately at admission, the suppuration of the lymph nodes required surgical drainage. Based on his anamnesis (sheep breeding; a twig scratching his eye 2 days before the initial attendance) and symptoms, a zoonosis, namely the oculoglandular form of tularemia, was suspected, empiric ciprofloxacin therapy was administered, and the patient recovered without sequelae. The Francisella tularensis infection was eventually confirmed by microagglutination serologic assay. CONCLUSIONS If Parinaud oculoglandular syndrome is diagnosed and cat scratch fever as the most common etiology is not likely, other zoonoses, especially the oculoglandular form of tularemia, should be suspected. Serology is the most common laboratory method of diagnosing tularemia. Empiric fluoroquinolone (ciprofloxacin) or aminoglycoside (gentamicin or streptomycin) antibiotic therapy should be started immediately at the slightest suspicion of oculoglandular tularemia.
Topics: Humans; Male; Tularemia; Aged; Francisella tularensis; Conjunctivitis, Bacterial; Syndrome; Anti-Bacterial Agents; Ocular Motility Disorders; Lymphadenopathy
PubMed: 38941282
DOI: 10.12659/AJCR.943915