Distribution of resistant gram-positive organisms across the census regions of the United States and in vitro activity of tigecycline, a new glycylcycline antimicrobial

Decoding the Structural Diversity: A New Horizon in Antimicrobial Prospecting and Mechanistic Investigation

The escalating crisis of antimicrobial resistance (AMR) underscores the urgent need for novel antimicrobials. One promising strategy is the exploration of structural diversity, as diverse structures can lead to diverse biological activities and mechanisms of action. This review delves into the role of structural diversity in antimicrobial discovery, highlighting its influence on factors such as target selectivity, binding affinity, pharmacokinetic properties, and the ability to overcome resistance mechanisms. We discuss various approaches for exploring structural diversity, including combinatorial chemistry, diversity-oriented synthesis, and natural product screening, and provide an overview of the common mechanisms of action of antimicrobials. We also describe techniques for investigating these mechanisms, such as genomics, proteomics, and structural biology. Despite significant progress, several challenges remain, including the synthesis of diverse compound libraries, the identification of active compounds, the elucidation of complex mechanisms of action, the emergence of AMR, and the translation of laboratory discoveries to clinical applications. However, emerging trends and technologies, such as artificial intelligence, high-throughput screening, next-generation sequencing, and open-source drug discovery, offer new avenues to overcome these challenges. Looking ahead, we envisage an exciting future for structural diversity-oriented antimicrobial discovery, with opportunities for expanding the chemical space, harnessing the power of nature, deepening our understanding of mechanisms of action, and moving toward personalized medicine and collaborative drug discovery. As we face the continued challenge of AMR, the exploration of structural diversity will be crucial in our search for new and effective antimicrobials.

Hospital-Level Antibacterial Prescribing and Its Completeness in Ethiopia: Did It Adhere to Good Prescribing Practice?

Background

Antibacterial agents are an integral part of chemotherapy and play a critical role in the prophylaxis and treatment of bacterial infections. However, prescribing errors such as incomplete prescriptions that do not adhere to good prescribing practice have become a contemporary concern in hospitals in resource-limited settings. Therefore, this study aimed to assess antibacterial prescribing and its completeness among prescriptions dispensed at four governmental hospitals in Eastern Ethiopia.

Methods

A cross-sectional study was employed to assess a total of 1308 prescription encounters containing at least one antibacterial agent obtained with simple random sampling from annual antibacterial-containing prescription data of four hospitals. The data were collected retrospectively using a structured checklist.

Results

A total of 2,855 drugs were prescribed from 1308 prescribing encounters with 1496 (52.39%) being antibacterial agents. The name, age, sex, and diagnosis of the patients were written in 1158 (88.3%), 815 (62.31%), 796 (60.58%), and 183 (13.99%) prescriptions, respectively. Besides, the route of administration, strength, duration, quantity, dose, and dosage form of the drug were recorded in 2322 (81.33%), 2118 (74.19%), 1516 (53.10%), 1525 (53.42%), 746 (26.13%) and 563 (19.72%) prescriptions, respectively. Nearly 50% of the prescribing encounters were documented without a prescriber name. Dispenser name and signature were also obtained in less than 10% of the prescriptions. Combining the data of all hospitals, amoxicillin, ceftriaxone, and ciprofloxacin were identified as the top three prescribed antibacterial drugs, whereas diclofenac, paracetamol, and tramadol were the most frequently co-indicated drugs. Regarding the pharmacologic class of antibiotics, penicillins were the most commonly prescribed antibiotics (n = 596, 39.77%) followed by cephalosporins (n = 318, 21.26%) and fluoroquinolones (n=285, 19.05%).

Conclusion

Incomplete information about patient-related factors and major diagnosis, medication regimens, prescribers and dispensers was identified as a potential prescribing error and did not adhere to good prescribing practice. This can be considered as one part of the inappropriate use of antibacterial agents, a driving force for the emergence of antimicrobial resistance. This problem requires immediate and sustained action from the management of the hospitals to ensure the accountability of health professionals involved in the medication use process and to establish antimicrobial stewardship programs in such resource-limited settings.

Hollow mesoporous hydroxyapatite nanostructures; smart nanocarriers with high drug loading and controlled releasing features

We report the development of effective drug loaded nanocarriers to combat multidrug resistant infection especially in case of osteomyelitis. The hollow mesoporous hydroxyapatite nanoparticles (hmHANPs) and solid/non-hollow hydroxyapatite nanoparticles (sHANPs) were synthesized by core-shell and co-precipitation techniques respectively. High encapsulation of the drug (ciprofloxacin) was observed in hmHANPs as compared to sHANPs, which may be due to the hollow porous structure of hmHANPs. These nanoparticles were characterized by scanning electron microscope (FESEM), N₂ adsorption/desorption, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA). Approximately 80% of the encapsulated drug was released at pH 4.5 within 5 days in case of hmHANPs while at pH 7.4, a sustained drug release profile was obtained and only 48.73% of the drug was released after 9 days. The results of kinetic drug release revealed that drug loaded hmHANPs showed fickian diffusion and anomalous drug diffusion mechanism at pH 4.5 and 7.4 respectively. Owing to their porous structure and high drug loading capacity, hmHANPs showed enhanced antibacterial activity against Staphylococcus aureus and Escherichia coli (drug resistant strains of osteomyelitis) in comparison to that with sHANPs. In addition, hmHANPs showed a pH sensitive drug release profile, high surface area (105.33 m²/g) with increased pore volume (0.533 cm³/g) and superior antimicrobial activity against osteomyelitis as compared to sHANPs.

Phenotypic and genetic characterization of multidrug-resistant Staphylococcus aureus in the tropics of Southeast Asia

Antibiotic resistance has become a major public health problem throughout the world. The presence of antibiotic-resistant bacteria such as Staphylococcus aureus and antibiotic resistance genes (ARGs) in hospital wastewater is a cause for great concern today. In this study, 276 Staph. aureus isolates were recovered from hospital wastewater samples in Malaysia. All of the isolates were screened for susceptibility to nine different classes of antibiotics: ampicillin, ciprofloxacin, gentamicin, kanamycin, erythromycin, vancomycin, trimethoprim and sulfamethoxazole, chloramphenicol, tetracycline and nalidixic acid. Screening tests showed that 100 % of Staph.aureus isolates exhibited resistance against kanamycin, vancomycin, trimethoprim and sulfamethoxazole and nalidixic acid. Additionally, 91, 87, 50, 43, 11 and 8.7 % of isolates showed resistance against erythromycin, gentamicin, ciprofloxacin, ampicillin, chloramphenicol and tetracycline, respectively. Based on these results, 100 % of isolates demonstrated multidrug-resistant (MDR) characteristics, displaying resistance against more than three classes of antibiotics. Of 276 isolates, nine exhibited resistance to more than nine classes of tested antibiotics; these were selected for antibiotic susceptibility testing and examined for the presence of conserved ARGs. Interestingly, a high percentage of the selected MDR Staph.aureus isolates did not contain conserved ARGs. These results indicate that non-conserved MDR gene elements may have already spread into the environment in the tropics of Southeast Asia, and unique resistance mechanisms against several antibiotics may have evolved due to stable, moderate temperatures that support growth of bacteria throughout the year.

Resistance pattern of ciprofloxacin against different pathogens

OBJECTIVES

Ciprofloxacin is a broad-spectrum antibiotic widely prescribed in clinical and hospital settings. The emergence of antimicrobial resistance against effective antibiotics is a global issue. The objective of study is the surveillance of ciprofloxacin against common pathogens.

METHODS

To investigate the present status of antimicrobial resistance against ciprofloxacin, five hundred and twenty four clinical isolates of Escherichia coli (30%), Staphylococcus aureus (33%), Salmonella typhi (9%), Klebsiella pneumonia (14%) and Pseudomonas aeruginosa (14%) were collected during study from January, 2008 to February, 2009 from different pathological laboratories running in and out side hospitals located in Karachi, Pakistan. These pathogens were isolated from specimens of both in and out patients. The in-vitro antimicrobial activity of ciprofloxacin was carried out by Disc Diffusion Method (Kirby-Bauer test).

RESULTS

Showed that ciprofloxacin is 27.02%, 21.95%, 16.66%, 72.22% and 44.44% resistant to Escherichia coli, Staphylococcus aureus, Salmonella typhi, Klebsiella pneumonia and Pseudomonas aeruginosa respectively.

CONCLUSION

It is concluded that these clinical isolates have started developing resistance against ciprofloxacin due to its irrational and inappropriate use. Continuous surveillance is crucial to monitor the antimicrobial resistance among pathogens.

Curbing the menace of antimicrobial resistance in developing countries

Several reports suggest that antimicrobial resistance is an increasing global problem; but like most pandemics, the greatest toll is in the less developed countries. The dismally low rate of discovery of antimicrobials compared to the rate of development of antimicrobial resistance places humanity on a very dangerous precipice. Since antimicrobial resistance is part of an organism's natural survival instinct, total eradication might be unachievable; however, it can be reduced to a level that it no longer poses a threat to humanity. While inappropriate antimicrobial consumption contributes to the development of antimicrobial resistance, other complex political, social, economic and biomedical factors are equally important. Tackling the menace therefore should go beyond the conventional sensitization of members of the public and occasional press releases to include a multi-sectoral intervention involving the formation of various alliances and partnerships. Involving civil society organisations like the media could greatly enhance the success of the interventions

Antimicrobial activity of tigecycline and comparative agents against clinical isolates of staphylococci and enterococci from ICUs and general hospital wards at three Swedish university hospitals

The activities of tigecycline and comparative agents on staphylococci and enterococci isolated from patients at general hospital wards (GHWs) and intensive care units (ICUs) at 3 university hospitals in Sweden were investigated. Oxacillin disc diffusion and minimal inhibitory concentration with E-test were used. The presence of mecA, vanA or vanB genes was determined with PCR. Statistically significant higher incidence of clindamycin, fusidic acid, rifampicin and multidrug-resistant CoNS was found at ICUs compared to GHWs. Resistance rates were low among S. aureus. Tigecycline, linezolid and vancomycin were the only agents with high activity against methicillin-resistant S. aureus and multidrug-resistant CoNS. Resistance rates were low among E. faecalis, except for high-level gentamicin-resistant (HLGR) E. faecalis. E. faecium showed high resistance rates to ampicillin, piperacillin/tazobactam and imipenem. The HLGR rates among E. faecium were lower than the rates for E. faecalis. Tigecycline and linezolid were the only drugs with high activity against all enterococci including vancomycin-resistant enterococci. No statistically significant differences in susceptibility rates were found between the ward levels for S. aureus and enterococcal isolates and no statistically significant differences were found between the hospitals.