Bacterial Exofactors Modulate Biofilm Growth and Resistivity to Antimicrobial Drugs

Some bacteria have the ability to co-exist, proliferate and survive in a multicellular community, biofilm. Each participating bacteria can form its colonies and encases itself by a self-produced insoluble extracellular matrix substance (EPS). Microcolonies within biofilm are held together by interactions and bonding of the substances present in the EPS with their separation from the water channels. Similar to insoluble EPS, bacterial microcolonies release soluble exofactors that have direct impacts on the survivability, growth and antibacterial resistivity of other microcolonies made of single- or multi-species bacteria in the same biofilm. How the exofactors of microcolonies of one-type bacteria impact on microcolonies of other-type bacteria is still unclear. We studied about the role of exofactors released from Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, which are common biofilm-forming pathogenic bacteria. Exofactors facilitate to transform the microenvironment where bacteria can acquire alternative lifestyle with a long survival period and resistivity to certain antimicrobial drugs.

Prostatic calculi influence the antimicrobial efficacy in men with chronic bacterial prostatitis

We studied the efficacy of culture-specific antibiotic therapy for chronic bacterial prostatitis （CBP） patients with or without prostatic calculi. This study included 101 patients （21-62 years old） who met the consensus criteria for CBP （National Institutes of Health category II）. According to the results of transrectal ultrasonography （TRUS）, all patients were divided into two groups： Group 1, CBP with prostatic calculi, n=39; Group 2, CBP without prostatic calculi, n=62. All patients received optimal antimicrobial therapy for 4 weeks and followed up for a minimum of 3 months （range： 3-8 months）. In addition to expressed prostatic secretions （EPS） and urine culture, all patients were asked to complete the National Institutes of Health Chronic Prostatitis Symptom Index （NIH-CPSI） and the subjective global assessment （SGA）. The microbiological eradication rate at the end of treatment were 32/39 （82.1%） and 54/62 （87.1%）, while the rates for continued eradication at the end of study were 17/39 （43.6%） and 45/62 （72.6%） in Group I and Group 2 （P〈0.01）, respectively. We observed a decrease in the total NIH-CPSI score median values from 24 to 19 in Group I and from 24 to 11 in Group 2. The pain subscore （P〈0.01）, urinary sunscore （P〈0.05） and quality of life （QoL; P〈0.05） as well as the total NIH-CPSI score （P〈0.01） were significantly improved after antimicrobial treatment in Group 2 compared to Group 1. Response, defined as a decrease of the NI H-CPSI total score by at least 50%, was seen in Group I versusGroup 2 in 38.5% and 58.1% （P〈0.01）, respectively. Our results showed that prostatic calculi influence the antimicrobial efficacy in men with CBP, There was a noticeable decrease in the cure rate of CBP patients with prostatic calculi due to relapse after antimicrobial therapy.

Six-year analysis of key monitoring for bacterial strain distribution and antibiotic sensitivity in a hospital

BACKGROUND With the widespread use of antimicrobial drugs,bacterial resistance has become a significant problem,posing a serious threat to public health.The prevalence of clinical infection strains in hospitals and their drug sensitivities are key to the appropriate use of antibiotics in clinical practice.AIM To identify prevalent bacteria and their antibiotic resistance profiles in a hospital setting,thereby guiding effective antibiotic usage by clinicians.METHODS Specimens from across the institution were collected by the microbiology laboratory.The VITEK 2 compact fully automatic analyzer was used for bacterial identification and antibiotic sensitivity testing,and the WHONET5.6 software was utilized for statistical analysis.RESULTS A total of 12062 bacterial strains of key monitoring significance were detected.Staphylococcus aureus demonstrated widespread resistance to penicillin,but none of the strains were resistant to vancomycin or linezolid.Moreover,219 strains of methicillin-resistant coagulase-negative staphylococci and 110 strains of methicillin-resistant Staphylococcus aureus were detected.Enterococcus faecalis showed moderate resistance to the third-generation quinolones ciprofloxacin and levofloxacin,but its resistance to nitrofurantoin and tetracycline was low.Enterococcus faecium displayed significantly lower resistance to third-and fourthgeneration quinolones than Enterococcus faecalis.The resistance of two key monitoring strains,Escherichia coli and Klebsiella pneumoniae,to piperacillin/tazobactam was 5%-8%.However,none of the Escherichia coli and Klebsiella pneumoniae strains were resistant to meropenem.The resistance of Acinetobacter baumannii to piperacillin/sulbactam was nearly 90%.Nonetheless,the resistance to tigecycline was low,and Pseudomonas aeruginosa demonstrated minimal resistance in the antibiotic sensitivity test,maintaining a resistance of<10%to the cephalosporin antibiotics cefotetan and cefoperazone over the last 6 years.The resistance to amikacin remained at 0.2%over the past 3 years.CONCLUSION Our hospital’s overall antibiotic resistance rate was relatively stable from 2017 to 2022.The detection rates of key monitoring strains are reported quarterly and their resistance dynamics are monitored and communicated to the entire hospital,which can guide clinical antibiotic selection.

Attempts to enhance the eradication rate of helicobacter pylori infection

Increasing rates of antimicrobial resistance to clarithromycin and metronidazole present challenges in maintaining optimal eradication rates.Knowledge of local antibiotic resistance and consumption pattern is important in selecting a reliable regimen.In addition,adverse effect profiles of therapeutic regimens are important and must be addressed to enhance compliance rates.Various methods of enhancing the eradication rates of Helicobacter pylori(H.pylori)have been investigated,including changing combinations or durations of established drugs,adding adjuvant drugs,or development of new molecules or agents.Bismuth-containing quadruple,sequential,concomitant,and levofloxacin-based triple therapies are replacing the long-standing standard of the triple regimen.Despite the encouraging results of these regimens,individualized approaches like treatment after antibiotics resistance test or CYP2C19genotyping would be the mainstream of future therapy.Because scientific,economic,and technical problems make these advance therapies unfit for widespread use,future development for H.pylori therapy should be directed to overcome individualized antibiotic resistance.Although various novel regimens and additive agents have indicated favorable outcomes,more studies or validations are needed to become a mainstream H.pylori therapy.

Antibiotic residues in milk and milk products:A momentous challenge for the pharmaceutical industry and medicine

Dairy products are nutritious food items that contain various essential nutrients,however,it has been proven that residual antibiotics have contaminated such products.These residues can cause several side effects on human health.They increase antimicrobial resistance against several threatening microorganisms,as well as significant growth in allergenic reactions.Various methods,including heat treatments,have been applied to alleviate and reduce the effect of antibiotic residue level in milk and milk products.Changes in drug levels were not sig-nificantly remarkable,obliging researchers to find new approaches to prevent or reduce their risk and limit their complications on human health.

Etiology and antimicrobial resistance of community-acquired pneumonia in adult patients in China

Background Appropriate antimicrobial therapy of community-acquired pneumonia （CAP） is mainly based on the distribution of etiology and antimicrobial resistance of major pathogens. We performed a prospective observational study of adult with CAP in 36 hospitals in China. Methods Etiological pathogens were isolated in each of the centers, and all of the isolated pathogens were sent to Zhongshan Hospital for antimicrobial susceptibility tests using agar dilution. Results A total of 593 patients were enrolled in this study, and 242 strains of bacteria were isolated from 225 patients. Streptococcus pneumoniae （79/242, 32.6%） was the most frequently isolated pathogen, followed by Haemophilus influenzae （55/242, 22.7%） and Klebsiella pneumoniae （25/242, 10.3%）. Totally 527 patients underwent serological tests for atypical pathogens; Mycoplasma pneumoniae and Chlamydia pneumoniae infections were identified in 205 （38.9%） and 60 （11.4%） patients respectively. Legionella pneumophila infections were identified in 4.0% （13/324） of patients. The non-susceptibility rate of isolated Streptococcus pneumoniae to erythromycin and penicillin was 63.2% and 19.1% respectively. Six patients died from the disease, the 30-day mortality rate was 1.1% （6/533）. Conclusions The top three bacteria responsible for CAP in Chinese adults were Streptococcus pneumonia, Haemophilus influenza and Klebsiella pneumonia. There was also a high prevalence of atypical pathogens and mixed pathogens. The resistance rates of the major isolated pathogens were relatively low except for the high prevalence of macrolide resistance in Streptococcus pneumoniae.

Novel berberine derivatives:Design,synthesis,antimicrobial effects,and molecular docking studies

A series of berberine derivatives were synthesized by introducing substituted benzyl groups at C-9.All these synthesized compounds（4a–4m）were screened for their in vitro antibacterial activity against four Gram-positive bacteria and four Gram-negative bacteria and evaluated for their antifungal activity against three pathogenic fungal strains.All these compounds displayed good antibacterial and antifungal activities,compared to reference drugs including Ciprofloxacin and Fluconazole;Compounds 4f,4g,and 4l showed the highest antibacterial and antifungal activities.Moreover,all the synthesized compounds were docked into topoisomerase Ⅱ-DNA complex,which is a crucial drug target for the treatment of microbial infections.Docking results showed that H-bond,π-πstacked,π-cationic,andπ-anionic interactions were responsible for the strong binding of the compounds with the target protein-DNA complex.

A perspective on general direction and challenges facing antimicrobial peptides

The emergence of drug resistant bacterium threatens the global public healthcare systems.The urgent need to obtain new antimicrobials has driven antimicrobial peptides（AMPs） research into spotlight.Here we give a brief introduction of the recent progress of AMPs regarding their structures,properties,production and modification,and antimicrobial mechanism.Thereby,this review will give an insight into the trends and challenges facing on this particular kind of antimicrobial materials.

A review of global initiatives to fight antibiotic resistance and recent antibiotics' discovery

Data from across the world have shown an overall decline in the antibiotic pipeline and continually rising resistance to all first-line and last-resort antibiotics. The gaps in our knowledge of existing prevalence and mechanisms of antibiotic resistance(ABR) are all too well known. Several decades of antibiotic abuse in humans, animals, and agricultural practices have created health emergency situations and huge socio-economic impact. This paper discusses key findings of the studies conducted by several national and international collaborative organizations on the current state of affairs in ABR.Alongside, a brief overview of the antibacterial agents' discovery in recent years approved by the US FDA is discussed.