Impact of mass administration of azithromycin as a preventive treatment on the prevalence and resistance of nasopharyngeal carriage of Staphylococcus aureus

In Vivo Acute Toxicity and Therapeutic Potential of a Synthetic Peptide, DP1 in a Staphylococcus aureus Infected Murine Wound Excision Model

Bacterial infections at the surgical sites are one of the most prevalent skin infections that impair the healing mechanism. They account for about 20% of all types of infections and lead to approximately 75% of surgical-site infection-associated mortality. Several antibiotics, such as cephalosporins, fluoroquinolones, quinolones, penicillin, sulfonamides, etc., that are used to treat such wound infections not only counter infections but also disrupt the normal flora. Moreover, antibiotics, when used for a prolonged duration, may impair the formation of new blood vessels, delay collagen production, or inhibit the migration of certain cells involved in wound repair, leading to an impaired healing process. Therefore, there is a dire need for alternate therapeutic approaches against such infections. Antimicrobial peptides have gained considerable attention as a promising strategy to counter these pathogens and prevent the spread of infection. Recently, we have reported a designed peptide, DP1, and its broad-spectrum in vitro antimicrobial activity against Gram-positive and Gram-negative bacteria. In the present study, in vivo acute toxicity of DP1 was evaluated and even at a high dose (20 mg/kg body weight) of DP1, a 100% survival of mice was observed. Subsequently, a Staphylococcus aureus-infected murine wound excision model was established to assess the wound healing efficacy of DP1. The study revealed significant wound healing vis-a-vis attenuated S. aureus bioburden at the wound site and also controlled the oxidative stress depicting anti-oxidant activity as well. Healing of the infected wounds was also verified by histopathological examination. Based on the results of this study, it can be concluded that DP1 improves wound resolution despite infections and promotes the healing mechanism. Hence, DP1 holds compelling potential as a novel antimicrobial drug that requires further explorations in clinical platforms.

Synthesis and biological evaluation of sulfonylpyridine derivatives as potential anti-chlamydia agents

Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection in the United States and the world. This pathogen can cause health problems ranging from trachoma (blindness) to damage of the fallopian tubes or ectopic pregnancy, which can be life-threatening if not treated properly. To this day, there is no chlamydia-specific drug on the market. Previously, we reported the activity and basic structure-activity relationships (SAR) of sulfonylpyridine molecules that possess antichlamydial action. Based on those results, we prepared a new series of derivatives. Our data indicate the new analogs can halt the growth of C. trachomatis. The lead compound, 22, was more active than our previous molecules and did not affect the growth of S. aureus and E. coli, suggesting bacterial selectivity. We performed docking studies on the presumed target, the cylindrical protease of Chlamydia. The in-silico studies partially explained the in vitro biological result as well as predicted a possible binding pose in the binding pocket. The top compound displayed a good cytotoxicity profile towards mammalian cell lines and was stable in both serum and stimulated gastric fluid. The presented data suggests the sulfonylpyridines are promising and selective anti-chlamydial compounds that merit further structural optimization.

Staphylococcus aureus and Coagulase-Negative Staphylococci from Bloodstream Infections: Frequency of Occurrence and Antimicrobial Resistance, 2018-2021

BACKGROUND

The abuse of antibiotics during the SARS-CoV-2 pandemic might have disrupted efforts to curb the further development and spread of the antimicrobial resistance of Staphylococcus aureus infection and Staphylococcus spp. coagulase-negative (CoNS) agents of nosocomial bloodstream infections (NBSIs). The purpose of our work was to study the resistance patterns of Staphylococcus aureus and CoNS through the analysis of blood cultures in hospitalized SARS-CoV-2-positive and SARS-CoV-2-negative patients (pts.).

MATERIALS AND METHODS

During the period January 2018-June 2021, a retrospective case-control study was performed on blood cultures positive for Staphylococcus spp. detected in 177 adult pts. (≥18 years old) hospitalized for >48 hours at Sant'Elia Hospital, Caltanissetta.

RESULTS

Staphylococcus aureus was isolated in 33.9% of blood culture samples, and among CoNS, the most frequent strains were Staphylococcus capitis (18.6%) and Staphylococcus hominis (18.1%). Patients aged ≥ 65 years, with a greater number of males, comprised the SARS-CoV-2-negative pts. (71.8% vs. 52.2%, p = 0.0154). Among the SARS-CoV-2-positive patients, the significant resistance of Staphylococcus aureus was only observed for erythromycin (57.1%). The oxacillin resistance of Staphylococcus capitis was higher in SARS-CoV-2-positive than in negative pts. (90% and 78.3%, respectively). Comparing the two groups, we found an increase in resistance in SARS-CoV-2-negative patients for the following antibiotics: gentamicin for Staphylococcus aureus (p = 0.007), clindamycin and erythromycin (p = 0.012) for Staphylococcus hominis and oxacillin and rifampicin for Staphylococcus haemoliticus (p = 0.012).

CONCLUSIONS

Our study confirms the relevance of oxacillin-resistant Staphylococcus aureus in being responsible for bloodstream infection and draws attention to highly oxacillin-resistant CoNS such as Staphylococcus capitis. The presence of resistant strains of CoNS in hospitals can be worrying, as it limits treatment options and worsens outcomes. The Infection Control Committee (ICC) recommends new treatment strategies to decrease colonization and infections. As part of the implementation of a bloodstream infection prevention program, the authors encourage the introduction of a report on the antimicrobial resistance of hospital bacteremia due to CoNS.

The impact of mass drug administration of antibiotics on the gut microbiota of target populations

Antibiotics have become a mainstay of healthcare in the past century due to their activity against pathogens. This manuscript reviews the impact of antibiotic use on the intestinal microbiota in the context of mass drug administration (MDA). The importance of the gut microbiota to human metabolism and physiology is now well established, and antibiotic exposure may impact host health via collateral effects on the microbiota and its functions. To gain further insight into how gut microbiota respond to antibiotic perturbation and the implications for public health, factors that influence the impact of antibiotic exposure on the microbiota, potential health outcomes of antibiotic-induced microbiota alterations, and strategies that have the potential to ameliorate these wider antibiotic-associated microbiota perturbations are also reviewed.