Staphylococcus aureus is responsible for skin and soft tissue infections that can progress to invasive and life-threatening infections. This bacterium easily acquires antibiotic resistance against all classes of antibiotics. Antimicrobial Photodynamic Therapy (aPDT) seems to be a very a promising alternative for the treatment of localized infections in response to the growing problem of antibiotic resistance, requiring only a photosensitizer, light and oxygen. Thus, the aim of this study was to evaluate the efficiency of a porphyrinic formulation (FORM) as photosensitizer in the photoinactivation of a methicillin-resistant S. aureus (MRSA) strain on skin. Potassium iodide (KI) and iodopovidone (PVP-I) were also tested in combination with FORM as aPDT potentiator agents. The in vitro results showed that FORM was effective to inactivate MRSA. A substantial reduction in the irradiation time, when compared to FORM alone, was observed for FORM + KI and FORM + PVP-I combinations. In the ex vivo assays with porcine skin artificially contaminated with the MRSA strain, reductions in bacterium survival of 3.1 Log₁₀ (CFU) mL⁻¹ were observed with FORM at 50 μM. Although the combined action of FORM + KI and FORM + PVP-I potentiated the aPDT efficacy in vitro, this effect was not observed ex vivo. Overall, the results showed that aPDT using FORM, even without coadjutants, is a promising approach for MRSA inactivation on skin.

Essential oils (EOs), which are complex biomolecules composed of volatile compounds, are being analyzed as tools to fight bacterial infections. Here, we report the modification of biodegradable wet-spun microfibers composed of cellulose acetate (CA) and polycaprolactone (PCL) with EOs, aiming at their localized, controlled release. Cinnamon leaf oil (CLO), cajeput oil (CJO), and clove oil (CO) were selected from a group of 20 EOs according to their minimal inhibitory concentration (MIC) against Staphylococcus aureus (<22.4 mg/mL) and Escherichia coli (<11.2 mg/mL). CA/PCL prepared at 10% and 14%wt in a 3/1 ratio in acetic acid and acetone were processed in the form of microfibers by wet-spinning at an extrusion rate of 0.5 mL/h directly into an ethanol coagulation bath. EOs were functionalized at the surface of the microfibers by physisorption. Here, microfibers were immersed in ethanol solutions containing EOs at 2xMIC and ampicillin (control antibiotic at 2xMIC, as well). After 72 h of immersion, fibers contained ampicillin at MIC but only 14%, 66% and 76% of MIC for CLO, CO and CJO, respectively. Incorporation was confirmed by UV-Visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and thermogravimetry (TGA). Unloaded and loaded microfibers were characterized as uniform and homogeneous. Time-kill kinetics antimicrobial studies (adaptation of ASTM-E2149-01) were conducted on the loaded fibers revealing their capability to eliminate more than 99.9% microbial cells after 24 h culture. Data showed that, even at small amounts, the EO-modified microfibers were effective against the bacteria S. aureus and E. coli. Considering the amount immobilized, CLO-containing fibers were deemed the most effective from the group, suggesting a superior affinity of the EOs active groups towards the CA/PCL matrix. These results indicate that CA/PCL microfibers loaded with EOs can be easily produced and applied in scaffolds for biomedical applications.

Chronic wounds (CW) create numerous entryways for pathogen invasion and prosperity, further damaging host tissue and hindering its remodeling and repair. Essential oils (EOs) exert quick and efficient antimicrobial (AM) action, unlikely to induce bacterial resistance. Cinnamon leaf and clove oils (CLO and CO) display strong AM activity, namely against Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan (CS) is a natural and biodegradable cationic polysaccharide, also widely known for its AM features. CS and poly (vinyl alcohol) (PVA) films were prepared (ratio 30/70 w/w; 9 wt%) by the solvent casting and phase inversion method. The film’s thermal stability and chemical composition data reinforced polymer blending and EO entrapment. Films were supplemented with 1 and 10 wt% of EO in relation to total polymeric mass. The film thickness and degree of swelling (DS) tended to increase with EO content, particularly with 10 wt % CLO (* p < 0.05). UV-visible absorbance scans in the 250–320 cm-1 region confirmed the successful uptake of CLO and CO into CS/PVA films, particularly with films loaded with 10 wt% EO that contained 5.30/5.32 times more CLO/CO than films supplemented with 1 wt% EO. AM testing (agar diffusion assay and time-kill kinetics) revealed that CS films alone were effective against both bacteria and capable of eradicating all P. aeruginosa within the hour (*** p < 0.001). Still, loaded CS/PVA films showed significantly improved AM traits in relation to unloaded films within 2 h of contact. This study is a first proof of concept that CLO and CO can be dispersed into CS/PVA films and show bactericidal effects, particularly against S. aureus, this way paving the way for efficient CW therapeutics.

Introduction: Staphylococcus aureus is a bacterium that lives in symbiosis with humans, it is an opportunistic and potentially lethal pathogen of clinical importance. Approximately 30% or more of the population is colonized with S. aureus on the skin, mucous membranes, or in the nose. The mechanisms of colonization and persistence of S. aureus in the human nose have been extensively studied, however, it must be admitted that the clinical relevance of S. aureus carriers in the pharynx has not been extensively investigated. The aim of this work was determinate the antibiotic resistance of S. aureus strains isolated from the pharynx and nose of young adults. Methods: Pharyngeal and nasal exudates were made to 134 University students of Health Science, once a month for three months. The exudate samples taken were incubated for 24 hours at 37 ºC for their subsequent sowing on the Salt-Mannitol agar. Identification of S. aureus strains is done by reseeding and isolating mannitol and coagulase positive fermenting bacteria. If a person registered three or more isolates of S. aureus in a row, he was considered a persistent carrier. The strains identified as S. aureus underwent the antibiogram test and MIC for oxacillin. Results: 62% of carriers presented S. aureus in pharynx and 36% in the nose. Only 17% of carriers presented S. epidermidis in the pharynx and 53% in the nose. Likewise, 35% were exclusive carriers of S. aureus in pharynx, 10% exclusive in the nose, 25% carriers in both sites, and 27% non-carriers. In addition, 49% are persistent carriers in the pharynx and 19% in the nose, 22% are intermittent carriers in the pharynx and 30% in the nose. Non-carriers of S. aureus in the pharynx and nose were 24% and 50%, respectively. 67% of S. aureus strains are resistant to penicillin, 23% resistant to clindamycin, 20% to erythromycin. Only 6% of the strains isolated from the pharynx and 5% from the nose are MRSA. Conclusion: The presence of S. aureus was greater in the pharynx than in the nose. The main antibiotic to which they are resistant is penicillin followed by clindamycin and erythromycin. A low percentage of MRSA strains was found.

Introduction. Staphylococcus aureus is an opportunistic pathogen of clinical importance, it can cause mild infections to death. The widespread use of antibiotics, particularly their inappropriate and excessive use, has favored the emergence and maintenance of strains of S. aureus resistant to multiple antibiotics such as penicillin or methicillin (methicillin-resistant S. aureus (MRSA) that are associated with high rates of morbidity and mortality in many regions of the world. The aim of this work was to determine the prevalence of MRSA strains in children from Mexico City. Methods. 476 pharyngeal and nasal exudates were performed on pediatric patients under 16 years of age between 2013 and 2019, they were inoculated on Mannitol Salt Agar and incubated for 24 hours at 37 °C. The presence of S. aureus was determined by fermentation of mannitol and positivity to coagulase. The minimum inhibitory concentration (MIC) for oxacillin were also performed. Methicillin resistant strains were those that grew in concentrations greater than 4 µg/mL. Results. A total of 240 women (50.42%) and 236 men (49.58%) (N = 476) with an average age of 7.39 years (+/- 2.76) were studied, in which 230 strains of S. aureus in the pharynx were isolated (48.31%), and 210 in nose (44.11%). Most isolated S. aureus strains are methicillin-sensitive (205 strains isolated from the pharynx and 176 strains from the nose), only 25 MRSA strains were isolated from the pharynx (5.25%) and 34 MRSA strains from the nose (7.14%). In addition, 137 carriers in both sites (28.78%), 93 exclusive carriers in the pharynx (19.53%) and 73 exclusive carriers in the nose (15.33%), and 246 non-carriers of S. aureus were found in both sites (51.68%). Conclusions. A greater number of S. aureus carriers were found in the pharynx than in the nose, the prevalence of MRSA strains is low, although most of the MRSA strains were found in the nose.

Colostrum can be responsible for colonizing calves gastrointestinal tract by antibiotic-resistant bacteria, such as Enterococcus faecalis one of the main indicators of fecal contamination and associated with nosocomial infections. In this work, the aim to characterize antibiotic resistance in E. faecalis isolates from colostrum used in the feeding of calves. Nineteen one isolates were recovered using agar selective plates and confirmed by biochemical and genetic tests. The antimicrobial susceptibility was performed using 14 antimicrobial agents by the disk diffusion method, according to the Clinical and Laboratory Standards Institute standards. The majority showed antibiotic-resistance to quinupristin-dalfopristin (81.3%), tetracycline (79.1%), erythromycin (79.1%) and streptomycin (57.1%). Isolates were less resistant to rifampicin (47.3%), chloramphenicol (25.3%) and ciprofloxacin (11.0%). Resistance to the remain antibiotics (vancomycin, teicoplanin, nitrofurantoin, fosfomycin and linezolid) was below 10%. None isolate showed resistance to ampicillin or gentamicin. In the 91 isolates analyzed, 85.7% proved to be multidrug-resistant. In conclusion, colostrum contains multidrug-resistant E. faecalis and constitutes a reservoir and vehicle for the transmission of these bacteria. For this reason, more prudent use of antibiotics in the therapy and prophylaxis of cattle is recommended, as well as, the correct management of the colostrum.

In 2019, a novel strain of coronavirus, SARS-CoV-2, was identified and the use of protective masks became essential. Considering most mask options display a passive-like action against COVID-19, we proposed the incorporation of anti-viral essential oils (EOs) onto nanofibrous mats, to function as inner layers in three-layer masks, and this way actively fight the virus.

Polycaprolactone (PCL) and cellulose acetate (CA) solutions were prepared individually at 14 wt% in chloroform/dimethylformamide (DMF) and 10 wt% in acetone/DMF, respectively, and then combined at 3:1 ratio. Polymeric solutions were processed via eletrospinning at 24.7 kV, 3.2 mL/h and 21 cm. Uniform, beadless nanofibers were obtained. Mats were characterized as mechanically resilient, to endure movements arising from mask handling, and hydrophobic in nature, to repel droplets coming from the exterior. Twenty EOs selected based on their antimicrobial nature were examined for the first time against the Escherichia virus MS2, a mimetic of COVID-19. The most effective were the lemongrass (LO), Niaouli (NO) and eucalyptus (ELO) with a minimum inhibitory concentration (MIC) of 356.0 mg/mL, 365.2 mg/mL and 586.0 mg/mL, respectively. Loading of the nanofibrous mats was accomplished via physisorption using the free -OH groups of the CA as linkers. Mats were loaded with the EOs at MIC concentration for 72 h (saturation) under constant agitation. Presence of the EOs was confirmed along the mats by UV/visible spectroscopy. Kirby-Bauer examinations verified the EOs-loaded mat’s diffusion abilities and antimicrobial effectiveness (formation of halos). Time-kill kinetics reported the elimination of >99% of MS2 virus in 6 h of contact. Data demonstrated the potential of these EOs-loaded PCL/CA nanofibers mats to work as COVID-19 active barriers in protection masks.

Antimicrobial resistance considerably affects the European Union, with estimated 33,000 yearly fatalities and 1.5 billion € yearly costs for health care needs and productivity loss. As urinary tract infections (UTIs) are common conditions primarily treated by antibiotics, rising antimicrobial resistance compels reconsidering the current use of antibiotics and alternative treatments for such infections. Our insights into the so far unexplored prescription of antibiotics in Europe illuminate the urgency of this issue.

Data on the prescription of broad-spectrum and UTI-specific antibiotics in European outpatient care were obtained from IQVIA MIDAS 2019. Broad-spectrum antibiotic consumption in Germany and France was matched with ICD10 prescription codes for a conservative estimate of UTI-related treatment share and used together with data from OECD and Statista 2020 to map per capita UTI-related to total antibiotic consumption across Europe.

652 million packages of broad-spectrum antibiotics and additional 30 million packages of so called UTI-specific antibiotics were consumed. Per capita consumption varies but is predominantly higher in South Europe. Share of UTI-related among broad-spectrum antibiotic prescriptions amounts to 13.1% in Germany and 5.4% in France, with majority provided for unspecified UTIs (Germany: 72.4%, France: 42.5%). Based on an estimated 9.1% average, UTI-related prescriptions rise to 89.6 million (13.1% of total antibiotic consumption).

Antibiotic consumption in Europe is generally high and notably affected by UTI-related prescriptions. Varying consumption across Europe reflects heterogeneous indications. In view of increasing antimicrobial resistance, effective alternative treatments will be relevant for future therapeutic strategies.

This work is a retrospective study of uterine lavage of mares with a history of sterility, sent by clinical veterinarians to the Infectious Pathology Department of the Clinical Veterinary Hospital of Cáceres during 2019.

The purpose of this study is to evaluate the prevalence of the main microorganisms isolated from uterine lavage of mares with reproductive problems, as well as the antimicrobial resistance of the different pathogens found.

A total of 66 samples were grown on selective and non-selective culture media and under different atmospheric conditions. The final identification was carried out by a commercial biochemical test (API; Biomerieux). Susceptibilities to different antibiotics were determined by Kirby-Bauer disk diffusion methods according to the Clinical Laboratory Standards Institute. The antimicrobials used were as follows: Ampicillin, Penicillin, Cefazolin, Ceftiofur, Cefquinome, Gentamicin, Amikacin, Enrofloxacin, Ciprofloxacin, Doxycycline and Trimethoprim/Sulfamethoxazole. All of them are widely used in equine clinics.

The results indicated a bacterial growth in 63.6% of the samples. Mixed growth (24.2%) was more frequent than pure growth. The most commonly isolated bacterial species was Escherichia coli (28.6%), followed by Streptococcus sp. (23.8%), Klebsiella sp. (15.9%) and Pseudomonas sp. (12.7%). On the other hand, fungi were isolated in 4.6% of them.

The main resistances observed in E. coli were to Doxycycline (44.4%), Ampicillin and Cefquinoma (38.9%), whereas the antibiotic to which they were most sensitive was Enrofloxacin (83.3%). In the case of Streptococcus sp., the most of these were resistant to Amikacin (100%) and Enrofloxacin (66.7%) and sensitive to Ceftiofur (88.7%). Klebsiella sp. was resistant to Ampicillin in all strains (100%) and Cefquinome (60%), and sensitive to Enrofloxacin (80%). Finally, Pseudomonas sp. showed high resistance to Ampicillin (75%) and Doxycycline and Trimethoprim / Sulfamethoxazole (62.5%) and showed a great sensitivity to Enrofloxacin (100%).

Biofilms underpin major health and economic burdens, accounting for up to 80% of all microbial infections in humans. Moreover, the treatment of biofilms has been increasingly troubled due to the rising of antibiotic resistance, which makes the use of antibiotics alone ineffective for treating biofilm-associated infections. In this way, novel antimicrobial strategies should be designed outside the constricted antibiotics box. Nowadays, natural products, in particular phytochemicals, have been explored as a promising antimicrobial approach due to their attractive source of eco-friendly, relatively inexpensive and broad-spectrum antimicrobials with low levels of cytotoxicity, coupled with their multiple action mechanisms that can prevent the emergence of resistant bacteria. However, though hopeful, the antimicrobial potential of phytochemicals is often weaker than that of common antibiotics. To address these issues, the present study investigated the antimicrobial potential of selected phytochemicals alone and in combination with standard antibiotics against Staphylococcus aureus, including a drug-resistant strain, and Escherichia coli. The antimicrobial activity of the phytochemicals alone and their combinations with gentamicin, mupirocin, and fusidic acid were determined through the minimum bactericidal concentration (MBC). Among the selected phytochemicals, citronellol presented the highest antimicrobial activity against S. aureus (MBC of 512 µg/mL) and cis-6-nonen-1-ol displayed the highest antimicrobial activity against both drug-resistant S. aureus and E. coli (MBC ranging from 1024 to 2048 µg/mL). In addition, bacterial cells were found to be eradicated at lower doses of selected phytochemicals and antibiotics when combined. This study highlights the promising phytochemical-antibiotic combinatorial approach for dealing with biofilm-associated infections.