Discovery of natural-product-derived sequanamycins as potent oral anti-tuberculosis agents.

The emergence of drug-resistant tuberculosis has created an urgent need for new anti-tubercular agents. Here, we report the discovery of a series of macrolides called sequanamycins with outstanding in vitro and in vivo activity against Mycobacterium tuberculosis (Mtb). Sequanamycins are bacterial ribosome inhibitors that interact with the ribosome in a similar manner to classic macrolides like erythromycin and clarithromycin, but with binding characteristics that allow them to overcome the inherent macrolide resistance of Mtb. Structures of the ribosome with bound inhibitors were used to optimize sequanamycin to produce the advanced lead compound SEQ-9. SEQ-9 was efficacious in mouse models of acute and chronic TB as a single agent, and it demonstrated bactericidal activity in a murine TB infection model in combination with other TB drugs. These results support further investigation of this series as TB clinical candidates, with the potential for use in new regimens against drug-susceptible and drug-resistant TB.

A novel 12-membered ring non-antibiotic macrolide EM982 attenuates cytokine production by inhibiting IKKß and IκBα phosphorylation.

Antimicrobial resistance poses a serious threat to human health worldwide and its incidence continues to increase owing to the overuse of antibiotics and other factors. Macrolide antibiotics such as erythromycin (EM) have immunomodulatory effects in addition to their antibacterial activity. Long-term, low-dose administration of macrolides has shown clinical benefits in treating non-infectious inflammatory respiratory diseases. However, this practice may also increase the emergence of drug-resistant bacteria. In this study, we synthesized a series of EM derivatives, and screened them for two criteria: (i) lack of antibacterial activity and (ii) ability to suppress tumor necrosis factor-α (TNF-α) production in THP-1 cells stimulated with lipopolysaccharide. Among the 37 synthesized derivatives, we identified a novel 12-membered ring macrolide EM982 that lacked antibacterial activity against Staphylococcus aureus and suppressed the production of TNF-α and other cytokines. The effects of EM982 on Toll-like receptor 4 (TLR4) signaling were analyzed using a reporter assay and Western blotting. The reporter assay showed that EM982 suppressed the activation of transcription factors, NF-κB and/or activator protein 1 (AP-1), in HEK293 cells expressing human TLR4. Western blotting showed that EM982 inhibited the phosphorylation of both IκB kinase (IKK) ß and IκBα, which function upstream of NF-κB, whereas it did not affect the phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase, and c-Jun N-terminal kinase, which act upstream of AP-1. These results suggest that EM982 suppresses cytokine production by inhibiting phosphorylation of IKKß and IκBα, resulting in the inactivation of NF-κB.

The mud-dwelling clam Meretrix petechialis secretes endogenously synthesized erythromycin.

Although lacking an adaptive immune system and often living in habitats with dense and diverse bacterial populations, marine invertebrates thrive in the presence of potentially challenging microbial pathogens. However, the mechanisms underlying this resistance remain largely unexplored and promise to reveal novel strategies of microbial resistance. Here, we provide evidence that a mud-dwelling clam, Meretrix petechialis, synthesizes, stores, and secretes the antibiotic erythromycin. Liquid chromatography coupled with mass spectrometry, immunocytochemistry, fluorescence in situ hybridization, RNA interference, and enzyme-linked immunosorbent assay revealed that this potent macrolide antimicrobial, thought to be synthesized only by microorganisms, is produced by specific mucus-rich cells beneath the clam's mantle epithelium, which interfaces directly with the bacteria-rich environment. The antibacterial activity was confirmed by bacteriostatic assay. Genetic, ontogenetic, phylogenetic and genomic evidence, including genotypic segregation ratios in a family of full siblings, gene expression in clam larvae, phylogenetic tree, and synteny conservation in the related genome region further revealed that the genes responsible for erythromycin production are of animal origin. The detection of this antibiotic in another clam species showed that the production of this macrolide is not exclusive to M. petechialis and may be a common strategy among marine invertebrates. The finding of erythromycin production by a marine invertebrate offers a striking example of convergent evolution in secondary metabolite synthesis between the animal and bacterial domains. These findings open the possibility of engineering-animal tissues for the localized production of an antibacterial secondary metabolite.

Novel Variant and Known Mutation in 23S rRNA Gene of Mycoplasma pneumoniae, Northern Vietnam, 2023.

During a 2023 outbreak of Mycoplasma pneumoniae-associated community-acquired pneumonia among children in northern Vietnam, we analyzed M. pneumoniae isolated from nasopharyngeal samples. In almost half (6 of 13) of samples tested, we found known A2063G mutations (macrolide resistance) and a novel C2353T variant on the 23S rRNA gene.

Macrolide-Resistant Mycoplasma pneumoniae Infections among Children before and during COVID-19 Pandemic, Taiwan, 2017-2023.

Before the COVID-19 pandemic, Mycoplasma pneumoniae infections emerged during spring to summer yearly in Taiwan, but infections were few during the pandemic. M. pneumoniae macrolide resistance soared to 85.7% in 2020 but declined to 0% during 2022-2023. Continued molecular surveillance is necessary to monitor trends in macrolide-resistant M. pneumoniae.

The intrinsic macrolide resistome of Escherichia coli.

Intrinsic resistance to macrolides in Gram-negative bacteria is primarily attributed to the low permeability of the outer membrane, though the underlying genetic and molecular mechanisms remain to be fully elucidated. Here, we used transposon directed insertion-site sequencing (TraDIS) to identify chromosomal non-essential genes involved in Escherichia coli intrinsic resistance to a macrolide antibiotic, tilmicosin. We constructed two highly saturated transposon mutant libraries of >290,000 and >390,000 unique Tn5 insertions in a clinical enterotoxigenic strain (ETEC5621) and in a laboratory strain (K-12 MG1655), respectively. TraDIS analysis identified genes required for growth of ETEC5621 and MG1655 under 1/8 MIC (n = 15 and 16, respectively) and 1/4 MIC (n = 38 and 32, respectively) of tilmicosin. For both strains, 23 genes related to lipopolysaccharide biosynthesis, outer membrane assembly, the Tol-Pal system, efflux pump, and peptidoglycan metabolism were enriched in the presence of the antibiotic. Individual deletion of genes (n = 10) in the wild-type strains led to a 64- to 2-fold reduction in MICs of tilmicosin, erythromycin, and azithromycin, validating the results of the TraDIS analysis. Notably, deletion of surA or waaG, which impairs the outer membrane, led to the most significant decreases in MICs of all three macrolides in ETEC5621. Our findings contribute to a genome-wide understanding of intrinsic macrolide resistance in E. coli, shedding new light on the potential role of the peptidoglycan layer. They also provide an in vitro proof of concept that E. coli can be sensitized to macrolides by targeting proteins maintaining the outer membrane such as SurA and WaaG.

Effects of quorum sensing-interfering agents, including macrolides and furanone C-30, and an efflux pump inhibitor on nitrosative stress sensitivity in Pseudomonas aeruginosa.

Long-term administration of certain macrolides is efficacious in patients with persistent pulmonary Pseudomonas aeruginosa infection, despite how limited the clinically achievable concentrations are, being far below their MICs. An increase in the sub-MIC of macrolide exposure-dependent sensitivity to nitrosative stress is a typical characteristic of P. aeruginosa. However, a few P. aeruginosa clinical isolates do not respond to sub-MIC of macrolide treatment. Therefore, we examined the effects of sub-MIC of erythromycin (EM) on the sensitivity to nitrosative stress together with an efflux pump inhibitor (EPI) phenylalanine arginyl ß-naphthylamide (PAßN). The sensitivity to nitrosative stress increased, suggesting that the efflux pump was involved in inhibiting the sub-MIC of macrolide effect. Analysis using efflux pump-mutant P. aeruginosa revealed that MexAB-OprM, MexXY-OprM, and MexCD-OprJ are factors in reducing the sub-MIC of macrolide effect. Since macrolides interfere with quorum sensing (QS), we demonstrated that the QS-interfering agent furanone C-30 (C-30) producing greater sensitivity to nitric oxide (NO) stress than EM. The effect of C-30 was decreased by overproduction of MexAB-OprM. To investigate whether the increase in the QS-interfering agent exposure-dependent sensitivity to nitrosative stress is characteristic of P. aeruginosa clinical isolates, we examined the viability of P. aeruginosa treated with NO. Although treatment with EM could reduce cell viability, a high variability in EM effects was observed. Conversely, C-30 was highly effective at reducing cell viability. Treatment with both C-30 and PAßN was sufficiently effective against the remaining isolates. Therefore, the combination of a QS-interfering agent and an EPI could be effective in treating P. aeruginosa infections.

Mycoplasmoides genitalium nucleic acid semi-quantitation and molecular macrolide resistance detection via automated assays: gender and specimen source considerations.

A laboratory-developed test (LDT) using analyte-specific reagents has been optimized on a commercial platform to detect macrolide resistance-associated mutations (MRM) in 23S rRNA from Mycoplasmoides genitalium from primary clinical specimens. In this study, MRM-LDT was applied to a multi-specimen source study set. One thousand four hundred ninety-five primary specimens testing positive for M. genitalium by commercial transcription-mediated amplification (TMA) were initially titered by the TMA assay using serial 10-fold dilutions to semi-quantitate target nucleic acid burden. Primary specimens were then processed for MRM detection using the MRM-LDT. Findings were stratified by gender and specimen source. The mean log10 target nucleic acid titer of a TMA-positive specimen was 3.51 (median 3; range 0-10). Male specimens (n = 1145) demonstrated a mean log10 M. genitalium TMA titer of 3.67; that value observed in 350 female specimens was 2.98 (P < 0.0001). The MRM-LDT detection rate (88.7%) from specimens with log10 M. genitalium TMA titers ≥ 4 was increased over specimens with log10 titers ≤ 1 (4.5%; P < 0.0002). In females, MRM-LDT was positive from 51.3% of vaginal swab and 34.7% of urine specimens (P = 0.01). In males, MRM-LDT was positive from 65.0% of rectal swab and 55.7% of urine specimens (P = 0.002). Differences were also observed in log10 M. genitalium TMA titers as a function of specimen source. M. genitalium macrolide resistance rates among multiple specimen sources, as determined by MRM-LDT, are high in the United States and can be consistent with target nucleic acid burden within the primary specimen. Caveats experienced within subgroupings support MRM reflex testing on primary M. genitalium-positive specimens. IMPORTANCE: First-line macrolide treatment failure is of increasing concern with Mycoplasmoides genitalium in multiple settings. Recent sexually-transmitted infection treatment guidelines from the United States Centers for Disease Control and Prevention have predicated therapeutic approaches on the availability of a macrolide resistance/susceptibility result from a primary clinical specimen. In this report, we investigate potential correlation between macrolide resistance mutation detection rates (identified by a molecular amplified laboratory-developed test) and transcription-mediated amplification-based rRNA target semi-quantitation. Data reveal that rRNA semi-quantitation and laboratory-developed test detection rate differences exist as a function of gender and specimen source. These data can guide providers in proper specimen selection not only for the laboratory diagnosis of M. genitalium but also macrolide resistance mutation determination from primary clinical specimens.

Identification of a 2-Aminobenzimidazole Scaffold that Potentiates Gram-Positive Selective Antibiotics Against Gram-Negative Bacteria.

The development of novel therapeutic approaches is crucial in the fight against multi-drug resistant (MDR) bacteria, particularly gram-negative species. Small molecule adjuvants that enhance the activity of otherwise gram-positive selective antibiotics against gram-negative bacteria have the potential to expand current treatment options. We have previously reported adjuvants based upon a 2-aminoimidazole (2-AI) scaffold that potentiate macrolide antibiotics against several gram-negative pathogens. Herein, we report the discovery and structure-activity relationship (SAR) investigation of an additional class of macrolide adjuvants based upon a 2-aminobenzimidazole (2-ABI) scaffold. The lead compound lowers the minimum inhibitory concentration (MIC) of clarithromycin (CLR) from 512 to 2 µg/mL at 30 µM against Klebsiella pneumoniae 2146, and from 32 to 2 µg/mL at 5 µM, against Acinetobacter baumannii 5075. Preliminary investigation into the mechanism of action suggests that the compounds are binding to lipopolysaccharide (LPS) in K. pneumoniae, and modulating lipooligosaccharide (LOS) biosynthesis, assembly, or transport in A. baumannii.

Molecular epidemiology of Mycoplasma pneumoniae pneumonia in children, Wuhan, 2020-2022.

BACKGROUND: Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of community-acquired pneumonia in children. The factors contributing to the severity of illness caused by M. pneumoniae infection are still under investigation. We aimed to evaluate the sensitivity of common M. pneumoniae detection methods, as well as to analyze the clinical manifestations, genotypes, macrolide resistance, respiratory microenvironment, and their relationship with the severity of illness in children with M. pneumoniae pneumonia in Wuhan. RESULTS: Among 1,259 clinical samples, 461 samples were positive for M. pneumoniae via quantitative polymerase chain reaction (qPCR). Furthermore, we found that while serological testing is not highly sensitive in detecting M. pneumoniae infection, but it may serve as an indicator for predicting severe cases. We successfully identified the adhesin P1 (P1) genotypes of 127 samples based on metagenomic and Sanger sequencing, with P1-type 1 (113/127, 88.98%) being the dominant genotype. No significant difference in pathogenicity was observed among different genotypes. The macrolide resistance rate of M. pneumoniae isolates was 96% (48/50) and all mutations were A2063G in domain V of 23S rRNA gene. There was no significant difference between the upper respiratory microbiome of patients with mild and severe symptoms. CONCLUSIONS: During the period of this study, the main circulating M. pneumoniae was P1-type 1, with a resistance rate of 96%. Key findings include the efficacy of qPCR in detecting M. pneumoniae, the potential of IgM titers exceeding 1:160 as indicators for illness severity, and the lack of a direct correlation between disease severity and genotypic characteristics or respiratory microenvironment. This study is the first to characterize the epidemic and genomic features of M. pneumoniae in Wuhan after the COVID-19 outbreak in 2020, which provides a scientific data basis for monitoring and infection prevention and control of M. pneumoniae in the post-pandemic era.

Mycoplasma pneumoniae infection outbreak in Guangzhou, China after COVID-19 pandemic.

BACKGROUNDS: Mycoplasma pneumoniae (M. pneumoniae) is a common pathogen causing respiratory diseases in children. This study aimed to characterize epidemiological and disease severity shifts of M. pneumoniae: infections in Guangzhou, China during and after the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Throat swab samples were obtained from 5405 hospitalized patients with symptoms of acute respiratory infections to detect M. pneumoniae. Differences in epidemiological and clinical characteristics of M. pneumoniae: infections were investigated during 2020-2022 and after COVID-19 pandemic (2023). RESULTS: M. pneumoniae were detected in 849 (15.6%, 849/5405) patients. The highest annual positive rate was 29.4% (754/2570) in 2023, followed by 5.3% (72/1367) in 2022, 1.2% (12/1015) in 2021, and 2.0% (11/553) in 2020, with significantly increasing annual prevalence from 2020 to 2023. M. pneumoniae incidence peaked between July and December post-COVID-19 pandemic in 2023, with the highest monthly positive rate (56.4%, 165/293). Clinical characteristics and outcomes of patients with M. pneumoniae did not vary between periods during and after COVID-19 pandemic except that patients with M. pneumoniae post-COVID-19 pandemic were more likely to develop fever. Patients with severe M. pneumoniae pneumonia (SMPP) were more likely to develop respiratory complications, myocardial damage, and gastrointestinal dysfunction than those with non-SMPP. Patients with SMPP had lower lymphocytes, CD3+ T cells, CD4+ T cells, CD8+ T cells, B cells, and higher IL-4, IL-6, IL-10 levels than those with non-SMPP. Bronchoalveolar lavage fluid specimens from infected patients were obtained to identify macrolide resistance mutations. Macrolide-resistant M. pneumoniae (MRMP) proportion in 2023 was 91.1% (215/236). CONCLUSION: Outbreaks of M. pneumoniae: occurred in Guangzhou, China in 2023 upon Non-pharmaceutical interventions easing. Despite the increasing incidence of M. pneumoniae, the disease severity remained similar during and after the COVID-19 pandemic.

Gene expression profile of Campylobacter jejuni in response to macrolide antibiotics.

Campylobacter jejuni is a foodborne pathogen that causes gastroenteritis in humans and has developed resistance to various antibiotics. The primary objective of this research was to examine the network of antibiotic resistance in C. jejuni. The study involved the wild and antibiotic-resistant strains placed in the presence and absence of antibiotics to review their gene expression profiles in response to ciprofloxacin via microarray. Differentially expressed genes (DEGs) analysis and Protein-Protein Interaction (PPI) Network studies were performed for these genes. The results showed that the resistance network of C. jejuni is modular, with different genes involved in bacterial motility, capsule synthesis, efflux, and amino acid and sugar synthesis. Antibiotic treatment resulted in the down-regulation of cluster genes related to translation, flagellum formation, and chemotaxis. In contrast, cluster genes involved in homeostasis, capsule formation, and cation efflux were up-regulated. The study also found that macrolide antibiotics inhibit the progression of C. jejuni infection by inactivating topoisomerase enzymes and increasing the activity of epimerase enzymes, trying to compensate for the effect of DNA twisting. Then, the bacterium limits the movement to conserve energy. Identifying the antibiotic resistance network in C. jejuni can aid in developing drugs to combat these bacteria. Genes involved in cell division, capsule formation, and substance transport may be potential targets for inhibitory drugs. Future research must be directed toward comprehending the underlying mechanisms contributing to the modularity of antibiotic resistance and developing strategies to disrupt and mitigate the growing threat of antibiotic resistance effectively.

Clinical characteristics and logistic regression analysis of macrolide-resistant Mycoplasma pneumoniae pneumonia in children.

PURPOSE: To investigate macrolide-resistant Mycobacterium pneumoniae (MRMP) pneumonia in children and construct a logistic regression model for mutations in the Mycoplasma pneumoniae drug-resistant gene. METHODS: Clinical data of 281 children were analyzed. Sequencing confirmed a mutation at the A2063G locus of the 23 S rRNA gene in 227 children (A2063G group); 54 children showed no mutations (non-MRMP [NMRMP] group). We compared clinical features, laboratory tests, imaging, and bronchoscopy results and constructed a multifactorial logistic regression model to analyze risk and protective factors. RESULTS: The A2063G group had longer durations of fever and hospitalization before admission, a higher proportion of treatment with sodium methylprednisolone succinate (MPS)/dexamethasone, longer time to discontinue hormones, and higher probability of combined infections. Monocyte percentage was significantly higher in the A2063G group. Imaging suggested a higher incidence of infections in the right lung compared to both lungs. Univariate analysis revealed fever duration before admission, hormone dose and duration, monocyte percentage, and mixed infections as risk factors for Mycoplasma pneumoniae infection with the A2063G mutation. The logistic regression model showed that mixed infections were an independent risk factor for the A2063G locus mutation, whereas hormone dose was a protective factor. CONCLUSION: A prevalence of macrolide resistance of 80.8% among children was observed in the region. Logistic regression analysis revealed that co-infection with other respiratory pathogens is an independent risk factor for the development of resistance genes, while the use of hormone dosage acts as a protective factor.

Comparison of gradient diffusion and molecular methods using Allplex™ NG&DR assay (Seegene®) for macrolide and fluoroquinolone screening resistance in Neisseria gonorrhoeae.

Antimicrobial resistance in Neisseria gonorrhoeae (NG) is increasing worldwide. Second-line treatments with macrolides or fluoroquinolones are an option for NG infections in some cases following the STI guideline recommendations. In our study, we compared the gradient diffusion test using EUCAST 2024 breakpoints with a new molecular method using the Allplex™ NG&DR assay (Seegene®) including A2059G/C2611 mutations (23S rRNA) associated with high/moderate-level macrolide resistance and S91F mutation (gyrA) relationship with fluoroquinolone resistance in NG isolates (n = 100). We calculated the sensitivity, specificity, and correlation of the molecular test for fluoroquinolone using the gradient diffusion as the reference method. In twenty-three strains was not detected any mutation associated with macrolides or fluoroquinolone resistance. No A2059G/C2611T mutations were detected, and the S91F mutations were detected in 77 out of the 100 isolates screened. Twenty-three NG isolates were reported to be resistant to azithromycin (ECOFF: >1 mg/L), and 78 NG isolates were resistant to ciprofloxacin (MIC: >0.06 mg/L). The molecular method showed a sensitivity of 96.1% and, a specificity of 90.9% for fluoroquinolone susceptibility, but the statistical analysis between the molecular test and gradient diffusion test was not statistically significant for fluoroquinolone resistance (p = 1). Statistical analysis was not performed for macrolides because of the absence of positive RT-PCR results. According to our data, Allplex™ assay cannot replace the gradient diffusion test for macrolide resistance. However, the assay could be used to test fluoroquinolone resistance in NG isolates as a replacement for phenotypic methods.

High cure rates of Mycoplasma genitalium following empiric treatment with azithromycin alongside frequent detection of macrolide resistance in Austria.

BACKGROUND: Mycoplasma genitalium (MG) is an emerging sexually transmitted infection, often harboring resistance-associated mutations to azithromycin (AZM). Global surveillance has been mandated to tackle the burden caused by MG, yet no data are available for Austria. Thus, we aimed to investigate the prevalence of MG, disease characteristics, and treatment outcomes at the largest Austrian HIV-and STI clinic. METHODS: All MG test results at the Medical University of Vienna from 02/2019 to 03/2022 were evaluated. Azithromycin resistance testing was implemented in 03/2021. RESULTS: Among 2671 MG tests, 199 distinct and mostly asymptomatic (68%; 135/199) MG infections were identified, affecting 10% (178/1775) of all individuals. This study included 83% (1479/1775) men, 53% (940/1775) men who have sex with men (MSM), 31% (540/1754) HIV+, and 15% (267/1775) who were using HIV pre-exposure prophylaxis (PrEP). In logistic regression analysis, 'MSM' (aOR 2.55 (95% CI 1.65-3.92)), 'use of PrEP' (aOR 2.29 (95% CI 1.58-3.32)), and 'history of syphilis' (aOR 1.57 (95% CI 1.01-2.24) were independent predictors for MG infections. Eighty-nine percent (178/199) received treatment: 11% (21/178) doxycycline (2 weeks), 52% (92/178) AZM (5 days), and 37% ( 65/178) moxifloxacin (7-10 days) and 60% (106/178) had follow-up data available showing negative tests in 63% (5/8), 76% (44/58) and 85% (34/40), respectively. AZM resistance analysis was available for 57% (114/199)) and detected in 68% (78/114). Resistance-guided therapy achieved a cure in 87% (53/61), yet, empiric AZM-treatment (prior to 03/2021) cleared 68% (26/38). CONCLUSIONS: Mycoplasma genitalium was readily detected in this Austrian observational study, affected predominantly MSM and often presented as asymptomatic disease. We observed a worryingly high prevalence of AZM resistance mutations; however, empiric AZM treatment cleared twice as many MG infections as expected.

Macrolide resistance of Mycoplasma pneumoniae in several regions of China from 2013 to 2019.

This paper retrospectively analysed the prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) in some parts of China. Between January 2013 and December 2019, we collected 4,145 respiratory samples, including pharyngeal swabs and alveolar lavage fluid. The highest PCR-positive rate of M. pneumoniae was 74.5% in Beijing, the highest resistance rate was 100% in Shanghai, and Gansu was the lowest with 20%. The highest PCR-positive rate of M. pneumoniae was 74.5% in 2013, and the highest MRMP was 97.4% in 2019; the PCR-positive rate of M. pneumoniae for adults in Beijing was 17.9% and the MRMP was 10.48%. Among the children diagnosed with community-acquired pneumonia (CAP), the PCR-positive and macrolide-resistant rates of M. pneumoniae were both higher in the severe ones. A2063G in domain V of 23S rRNA was the major macrolide-resistant mutation, accounting for more than 90%. The MIC values of all MRMP to erythromycin and azithromycin were ≥ 64 µg/ml, and the MICs of tetracycline and levofloxacin were ≤ 0.5 µg/ml and ≤ 1 µg/ml, respectively. The macrolide resistance varied in different regions and years. Among inpatients, the macrolide-resistant rate was higher in severe pneumonia. A2063G was the common mutation, and we found no resistance to tetracycline and levofloxacin.

Prevalence and macrolide resistance of Mycoplasma genitalium from patients seeking sexual health care in Southern Ghana.

BACKGROUND: Mycoplasma genitalium (MG), a sexually transmitted infection (STI), has emerged as a common cause of non-gonococcal urethritis and cervicitis worldwide, with documented resistance to commonly used antibiotics including doxycycline and azithromycin. Data in Ghana regarding the prevalence of MG is limited. METHODS: This retrospective study investigated MG presence and macrolide resistance among patients who previously reported to selected clinics for STI symptoms between December 2012 and June 2020. Samples were screened for MG and mutations associated with azithromycin resistance were investigated using Nucleic Acid Amplification Testing (NAAT) including the Resistance Plus MG® kit from SpeeDx and the LightMix® kit for MG, combined with the Modular Mycoplasma Macrolide from TIB Molbiol. RESULTS: A total of 1,015 samples were screened, out of which MG infection rate by TIB Molbiol and SpeeDx were 3.1% and 3.4%, respectively. The mutation responsible for macrolide resistance was detected in one MG positive sample by both assays. Both diagnostic tests revealed no significant association between MG infection and socio-demographic characteristics, clinical symptoms, gonorrhea, and chlamydia infection status. There was no significant difference in the mycoplasma percentage positivity rate detected using SpeeDx (3.4%) and TIB Molbiol (3.1%). CONCLUSIONS: While not commonly tested as a cause of STI symptoms, MG is widespread in Ghana, exhibiting symptoms and prevalence comparable to those in other countries and linked to antimicrobial resistance. Future research using various molecular techniques is essential to monitor resistance trends and guide future antibiotic choices.

Clinical efficacy of macrolide antibiotics in mycoplasma pneumoniae pneumonia carrying a macrolide-resistant mutation in the 23 S rRNA gene in pediatric patients.

BACKGROUND: The global prospective surveillance data showed the re-emergence of mycoplasma pneumoniae pneumonia (MPP) in Europe and Asia after the coronavirus disease 2019 pandemic. We sought to observe the effect of macrolide antibiotics in the treatment of MPP carrying a macrolide-resistant mutation gene and the potential of targeted next-generation sequencing (tNGS) as a front-line diagnostic in MPP patients. METHODS: The baseline characteristics of 91 children with MPP hospitalized from January to October 2023 were retrospectively analyzed. They were divided into two groups according to whether carrying the macrolide-resistant mutation or not. The logistic and linear regression analyses were used to determine whether the mutation was a standalone predictive predictor of the duration of fever and hospital length of stay. RESULTS: First, no patients had a fever for ≥ 7 days after macrolide treatment. But length of stay and hormone concentration were significantly different between the two groups (P < 0.05). There were also no statistical association between the mutation and the duration of fever and hospital length of stay. CONCLUSION: Macrolides can be administered to MPP children carrying a macrolide-resistant mutation. tNGS can be seen as a front-line diagnostic in MPP.

Design and structure-activity relationships of ether-linked alkylides: Hybrids of 3-O-descladinosyl macrolides and quinolone motifs.

Ketolides (3-keto) such as TE-802 and acylides (3-O-acyl) like TEA0929 are ineffective against constitutively resistant pathogens harboring erythromycin ribosomal methylation (erm) genes. Following our previous work on alkylides (3-O-alkyl), we explored the structure-activity relationships of hybrids combining (R/S) 3-descladinosyl erythromycin with 6/7-quinolone motifs, featuring extended ether-linked spacers, with a focus on their efficacy against pathogens bearing constitutive erm gene resistance. Optimized compounds 17a and 31f not only reinstated efficacy against inducibly resistant pathogens but also demonstrated significantly augmented activities against constitutively resistant strains of Streptococcus pneumoniae and Streptococcus pyogenes, which are typically refractory to existing C-3 modified macrolides. Notably, hybrid 31f (coded ZN-51) represented a pioneering class of agents distinguished by its dual modes of action, with ribosomes as the primary target and topoisomerases as the secondary target. As a novel chemotype of macrolide-quinolone hybrids, alkylide 31f is a valuable addition to our armamentarium against macrolide-resistant bacteria.

Macrolide sesquiterpene pyridine alkaloids from Celastrus monospermus and evaluation of their immunosuppressive and anti-osteoclastogenesis activities.

Phytochemical investigation of the stems of Celastrus monospermus Roxb enabled isolation and identification of fifteen new macrolide sesquiterpene pyridine alkaloids (1-15) along with five known analogues. Their structures were elucidated by comprehensive spectroscopic analysis (NMR, HRESIMS, IR, UV), chemical hydrolysis, and single crystal X-ray diffraction analysis. Bioassay of the abundant isolates revealed that seven compounds inhibited the proliferation of B lymphocytes with IC50 values ranging between 1.4 and 19.9 µM. Among them, celasmondine C (3) could significantly promote the apoptosis of activated B lymphocyte, especially late-stage apoptosis. Besides, compounds 3, 16, and 20 exhibited potent suppression of osteoclast formation at a concentration of 1.0 µM. This investigation enriched the chemical diversity of macrolide sesquiterpene pyridine alkaloids, and supported evidence for the development of new immunosuppressive and anti-osteoclastogenesis agents.