Antibiotic-resistant Microorganisms Research Articles

Antibacterial, Phytochemical and Toxicological Activities of Garcinia kola Extracts against Multidrug Resistant Clinical Bacteria

Objective: The rise in multiple antibiotic resistant microorganisms has led to a decline in the efficacy of many antibiotics, prompting the investigation of alternative solutions such as medicinal plants. To tackle this concerning issue, this study was undertaken to evaluate the phytochemical composition, antibacterial activity, and toxicological characteristics of Garcinia kola extracts against multidrug-resistant bacteria commonly found in clinical settings. Material-Method: The cold maceration technique was employed to extract the root and leaf of Garcinia kola using water and methanol. The extracts were then subjected to phytochemical screening. To evaluate the extracts' potential to inhibit bacterial growth, five multidrug-resistant isolates were utilized in this study. Agar well assay was used to determine the zones of inhibition. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined using the broth macro dilution technique. Additionally, Brine shrimp lethality assay was conducted to determine the lethal concentration (LC50) of the extracts. The extracts were also combined for synergism. Results: The investigation found that the root extract in methanol had the highest yield at 25.58%. All four extracts contained ten out of the fourteen tested phytochemicals. The methanol leaf and root extracts exhibited the highest and lowest inhibition zones of 20mm and 9mm against Staphylococcus aureus, respectively. The MIC values ranged from 250 to 600 mg/ml, indicating broad-spectrum antibacterial activity. The cytotoxicity test showed a range of 33.03 to 126.3µg/mL for the aqueous and methanol extracts. Conclusion: Although Garcinia kola shows potential as a source of antibacterial compounds, caution should be exercised due to its toxic effects.

Antibiotic resistance of microorganisms isolated from the urine of patients before surgical treatment for benign prostatic hyperplasia: results from a 7-year single-center study

Introduction. The tendency of microorganisms to develop resistance mechanisms is a widely discussed and significant problem worldwide. Studying regional differences in the qualitative characteristics of microorganisms provides valuable information for empirically preventing and treating infectious complications, as well as providing an enhanced understanding of the variability in microbial community properties within the clinical context of diseases and patients' comorbidity status.Objective. To assess the antibiotic resistance of microorganisms isolated in high titers from the urine samples of patients with benign prostate hyperplasia (BPH) prior to surgery.Materials & Methods. This single-center, retrospective study conducted from March 2016 to February 2023 included 59 suprapubic-draining BPH-patients (Group I), 46 drainage-free BPH-patients with leukocyturia (Group II), and 44 drainage-free BPH-patients and no leukocyturia (Group III). Inclusion criteria: indications for BPH surgery, no history of sexually transmitted diseases, no symptoms of urinary tract infection, and no prostate cancer. The patient's voluntary informed consents to participate were also obtained.Results. The rates of resistance to ciprofloxacin in patients of Group I were statistically significantly higher compared to Group II (85.7% vs 55.6%, p = 0.002). Resistance of gram-negative microorganisms to meropenem and imipenem was higher in Group III compared to Group I (31.1% vs 13.7%, p = 0.006 for meropenem and 44.5% vs 9.8%, p = 0.001 for imipenem, respectively). Resistance of Gram-positive microorganisms to ampicillin in Groups I to III was 13.6%,6.3% and 20.0%, respectively with no significant difference between groups (p > 0.05). However, there was extremely high resistance among verified Gram-positive organisms to all the drugs in the fluoroquinolone class (ciprofloxacin, norfloxacin, levofloxacin) ranged from 63.6% to 80.0%.Conclusion. The present study demonstrates that the isolation frequency of antibiotic-resistant microorganisms from the urine sample of drainage-free BPH-patients or no clinical and laboratory signs of inflammation in the urinary tract is high. The presence of antibiotic resistance provides risks for developing difficult-to-control infectious complications. Currently, assessment of urine-derived microbial antibiotic resistance should be considered in every BPH-patient with indications for surgical management of bladder outlet obstruction, regardless of the presence of risk factors.

Proteomic profiling of antibiotic-resistant Escherichia coli GW-AmxH19 isolated from hospital wastewater treated with physical plasma.

Microorganisms which are resistant to antibiotics are a global threat to the health of humans and animals. Wastewater treatment plants are known hotspots for the dissemination of antibiotic resistances. Therefore, novel methods for the inactivation of pathogens, and in particular antibiotic-resistant microorganisms (ARM), are of increasing interest. An especially promising method could be a water treatment by physical plasma which provides charged particles, electric fields, UV-radiation, and reactive species. The latter are foremost responsible for the antimicrobial properties of plasma. Thus, with plasma it might be possible to reduce the amount of ARM and to establish this technology as additional treatment stage for wastewater remediation. However, the impact of plasma on microorganisms beyond a mere inactivation was analyzed in more detail by a proteomic approach. Therefore, Escherichia coli GW-AmxH19, isolated from hospital wastewater in Germany, was used. The bacterial solution was treated by a plasma discharge ignited between each of four pins and the liquid surface. The growth of E. coli and the pH-value decreased during plasma treatment in comparison with the untreated control. Proteome and antibiotic resistance profile were analyzed. Concentrations of nitrite and nitrate were determined as long-lived indicative products of a transient chemistry associated with reactive nitrogen species (RNS). Conversely, hydrogen peroxide served as indicator for reactive oxygen species (ROS). Proteome analyses revealed an oxidative stress response as a result of plasma-generated RNS and ROS as well as a pH-balancing reaction as key responses to plasma treatment. Both, the generation of reactive species and a decreased pH-value is characteristic for plasma-treated solutions. The plasma-mediated changes of the proteome are discussed also in comparison with the Gram-positive bacterium Bacillus subtilis. Furthermore, no effect of the plasma treatment, on the antibiotic resistance of E. coli, was determined under the chosen conditions. The knowledge about the physiological changes of ARM in response to plasma is of fundamental interest to understand the molecular basis for the inactivation. This will be important for the further development and implementation of plasma in wastewater remediation.

Significance of colonization by antibiotic-resistant organisms prior to congenital heart disease surgery in children from low- to middle-income countries sent by non-governmental organizations to Switzerland.

Children with congenital heart disease (CHD) from low- to middle-income countries (LMIC) are suspected to have a high prevalence of antibiotic-resistant microorganisms (ARMOs) carriage, but data are currently lacking. Carriage of ARMOs could impact the post-operative course in pediatric intensive care unit (PICU). The aim of the study was to assess the prevalence of ARMOs carriage in children with CHD from LMIC and its impact on post-operative outcomes. This was a retrospective monocentric study from 01/2019 to 12/2022. Included patients were children (0-18 years) from a LMIC admitted after CHD surgery and with AMRO screening performed the week before. Infections and post-operative evolution were compared based on ARMOs carriage status. Among 224 surgeries (median age 38.5 months (IQR 22-85.5)), ARMOs carriage was evidenced in 95 cases (42.4%). Main organisms isolated were Extended Spectrum Beta-Lactamase (ESBL) producing E. coli (75/224) 33.5%)) and ESBL-K. pneumoniae (30/224) 13.4%)). Median mechanical ventilation duration was 1 day (IQR 0-1), PICU stay 3 days (IQR 2-4) and hospital stay 6.5 days (IQR 5-10). A total of 17 infectious episodes occurred in 15 patients, mostly consisting in hospital-acquired pneumonia (HAP) (12/17). Only two infections were caused by a colonizing ARMO. Occurrence of infections and patients' outcome were similar between ARMO carriers and non-carriers. Higher use of carbapenems (6 (6.3%) vs 1 (0.8%), p = 0.04) and a trend to a higher use of vancomycin (14 (13.7%) vs 9 (6.9%), p = 0.04) in case of ARMOs carriage. Applying current guidelines, negative swab screening could have led to sparing most of empirical vancomycin therapy (11/12) for HAP based on current guidelines. Prevalence of AMROs carriage is high in children from LMIC and has a limited impact on patients' outcome. However, ARMOs carriage leads to higher consumption of antibiotics. Screening may help saving use of broad-spectrum antibiotic in non-carrier patients.

Cell-Free Supernatant from a Strain of Bacillus siamensis Isolated from the Skin Showed a Broad Spectrum of Antimicrobial Activity.

In recent years, the search for new compounds with antibacterial activity has drastically increased due to the spread of antibiotic-resistant microorganisms. In this study, we analyzed Cell-Free Supernatant (CFS) from Bacillus siamensis, assessing its potential antimicrobial activity against some of the main pathogenic microorganisms of human interest. To achieve this goal, we exploited the natural antagonism of skin-colonizing bacteria and their ability to produce compounds with antimicrobial activity. Biochemical and molecular methods were used to identify 247 strains isolated from the skin. Among these, we found that CFS from a strain of Bacillus siamensis (that we named CPAY1) showed significant antimicrobial activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, and Candida spp. In this study, we gathered information on CFS's antimicrobial activity and on its sensitivity to chemical-physical parameters. Time-kill studies were performed; anti-biofilm activity, antibiotic resistance, and plasmid presence were also investigated. The antimicrobial compounds included in the CFS showed resistance to the proteolytic enzymes and were heat stable. The production of antimicrobial compounds started after 4 h of culture (20 AU/mL). CPAY1 CFS showed antimicrobial activity after 7 h of bacteria co-culture. The anti-biofilm activity of the CPAY1 CFS against all the tested strains was also remarkable. B. siamensis CPAY1 did not reveal the presence of a plasmid and showed susceptibility to all the antibiotics tested.

Identification and biological characteristics of Enterococcus casseliflavus TN-47 isolated from Monochamus alternatus.

With the widespread use of antibiotics, the incidence of antibiotic resistance in microorganisms has increased. Monochamus alternatus is a trunk borer of pine trees. This study aimed to investigate the in vitro antimicrobial and biological characteristics of Enterococcus casseliflavus TN-47 (PP411196), isolated from the gastrointestinal tract of M. alternatus in Jilin Province, PR China. Among 13 isolates obtained from the insects, five were preliminarily screened for antimicrobial activity. E. casseliflavus TN-47, which exhibited the strongest antimicrobial activity, was identified. E. casseliflavus TN-47 possessed antimicrobial activity against Staphylococcus aureus USA300 and Salmonella enterica serovar Pullorum ATCC 19945. Furthermore, E. casseliflavus TN-47 was sensitive to tetracyclines, penicillins (ampicillin, carbenicillin, and piperacillin), quinolones and nitrofuran antibiotics, and resistant to certain beta-lactam antibiotics (oxacillin, cefradine and cephalexin), macrolide antibiotics, sulfonamides and aminoglycosides. E. casseliflavus TN-47 could tolerate low pH and pepsin-rich conditions in the stomach and grow in the presence of bile acids. E. casseliflavus TN-47 retained its strong auto-aggregating ability and hydrophobicity. This strain did not exhibit any haemolytic activity. These results indicate that E. casseliflavus TN-47 has potential as a probiotic. This study provides a theoretical foundation for the future applications of E. casseliflavus TN-47 and its secondary metabolites in animal nutrition and feed.

Isolation, prevalence of bacteria and fungi from carcasses and different locations within Yola abattoir and antimicrobial resistance profile of Escherichia coli O157:H7

The absence of modern slaughtering facilities and an unhygienic environment in Yola abattoir may result in an outbreak of antibiotic-resistant pathogenic microorganisms, leading to economic loss and human death. Hence, this study was carried out to isolate and assess the prevalence of bacteria and fungi within the abattoir environment as well as to determine the antimicrobial resistance profile of E. coli O157:H7 from different locations and carcasses. A cross-sectional study was conducted where a simple random sampling method was used for sampling. A total of 156 samples were collected. Isolation and identification of bacteria and fungi were done using standard methods. Pseudomonas was the most dominant bacterial species with a total of 151 isolates, followed by E. coli 143 and Klebsiella with 123 isolates. The highest prevalence in fungi was recorded in Aspergillus flavus at 17.6 %, followed by Aspergillus niger at 15.1 % and Trichophyton rubrum and Penicillium that had 14.5 % respectively. The highest mean air-borne coliform count was in the Lairage, it ranged between 1.1 x 106 CFU/m3 and 1.7 x 106 CFU/m3. A hundred and forty-three E. coli were isolated out of which six (4.2 %) were characterized to be E. coli O157:H7 producing characteristic colorless colonies on cefixime tellurite sorbitol MacConkey (CT-SMAC) agar. All the six E. coli O157:H7 were resistant to at least two antibiotics, ampicillin, and amoxicillin-clavulanic acid while ciprofloxacin, trimethoprim-sulfamethoxazole, and tetracycline were effective against the six E. coli O157:H7. The MAR ranged between 0.2 and 0.7. The results obtained in this study showed that there is a need for modern facilities in Yola abattoir, training of workers on hygiene, and a hygienic environment to avoid microbial contamination and spread of antimicrobial-resistant pathogenic strains like E. coli O157:H7 and mycotoxin producer Aspergillus flavus.

Effect of Treated Wastewater on the Distribution of Antibiotic-Resistant Microorganisms in the Aquatic Environment

Effect of Treated Wastewater on the Distribution of Antibiotic-Resistant Microorganisms in the Aquatic Environment

What Is the Rate of Antimicrobial Resistance of a Prosthetic Joint Infection in a Major Orthopaedic Centre?

Periprosthetic joint infections (PJIs) are important factors in decreasing the success of hip and knee arthroplasties. It is a necessity to explore the epidemiological data and develop applications for rational antibiotic use, to address future infection control concerns. We aimed to investigate the microorganisms that were responsible and the related antibiograms in 121 patients with PJI, who were managed by two-stage revision surgery. Patients' data records, demographics, comorbidities, sites of arthroplasty, synovial fluid and deep tissue culture results and antibiotic treatment were summarized on a standardized case report form. There were 43 (35.5%) culture-negative PJI cases and 12 (9.9%) polymicrobial growths. The causative pathogens included Gram-positive (50.4%) and Gram-negative microorganisms (23.1%) and fungi (0.8%). Methicillin resistance was 64.3% for S. aureus and 89.5% for coagulase-negative staphylococcus (CoNS). The extended spectrum beta lactamase (ESBL) rate for Enterobacteriaceae was 68.4%. This study shows that antibiotic resistance is encountered in more than half of the cases, which is valid for all microorganisms most common in PJI. The success of treatment decreases significantly in cases where antibiotic-resistant microorganisms are isolated or in cases where the culture is negative.

Optimization of Culture Conditions and Batch Process Control for the Augmented Production of Bacteriocin by Bacillus Species.

The emergence of antibiotic-resistant microorganisms poses a significant threat to human health worldwide. Recent advances have led to the discovery of molecules with potent antimicrobial activity from environmental sources. In this study, fifteen bacterial isolates were obtained from agricultural and polluted soil samples collected from different areas of the cities of Jizan and Jeddah. These isolates were screened for antagonistic activity against a set of human pathogenic bacterial strains. The results showed that two Bacillus strains, identified as Bacillus atrophaeus and Bacillus amyloliquefaciens based on 16S rDNA, synthesized bacteriocin with strong antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 33591, Pseudomonas aeruginosa ATCC 9027, Salmonella typhimum ATCC 14028, carbapenem-resistant E. coli, and MRSA 2. To optimize bacteriocin production, the effects of medium composition, incubation period, temperature, and pH were investigated. Nutrient broth and Mueller-Hinton broth were chosen as the optimal original media for bacteriocin production. The optimal incubation period, temperature, and pH were found to be 48 h at 37 °C and 7 pH in Bacillus atrophaeus and 72 h at 37 °C and 8 pH in Bacillus amyloliquefaciens. Batch cultures of Bacillus atrophaeus and Bacillus amyloliquefaciens were grown in a 10 L benchtop bioreactor, and pH control was found to significantly increase the production of bacteriocin by two-fold compared to uncontrolled conditions. The time course of growth, substrate consumption, pH, and enzyme production were investigated. This study demonstrates the potential of optimizing culture conditions and batch process control to enhance bacteriocin production by Bacillus spp.

Etiology and epizootology of bovine mastitis (analytical review)

Mastitis is one of the most common global diseases of dairy cattle, it is detected in 5–36% animals in a herd undergoing a single examination, and the incidence reaches 68% within a year, given that some cows get reinfected more than once. The disease causes significant economic losses to dairy industry both in the Russian Federation and globally. Mastitis is an inflammation of the mammary gland that develops in response to the effects of various factors of the external and internal environment, which are classified as mechanical, physical, biological, etc. Based on the clinical symptoms, the disease has two forms: clinical and subclinical. Both the animal and its milk shall be subjected to a thorough examination for the diagnosis establishment. The final stage of the mastitis diagnosis in cows is laboratory testing. In this case, the most informative is the bacteriological method, which helps to isolate a pathogen’s pure culture, identify it and determine sensitivity to antimicrobial drugs. The latter plays a specific role in indicating the direction of further therapeutic measures, since the obtained data facilitate selection of effective antibiotics against certain pathogens. Incorrect treatment, incompliances with the prescribed therapy, as well as unnecessary use of antimicrobials can lead to the generation of multi-resistant bacteria. Due to the widespread spread of antibiotic-resistant microorganism strains, despite the large number of drugs currently used, their effectiveness is constantly decreasing. The prospects for the further use of antibiotics as therapeutics are questioned by many researchers and international organizations due to antibiotic resistance rapidly developing in many agents. Vaccination plays a significant role in infectious disease control. The use of vaccines not only reduces mastitis occurrence in cows, but also significantly improves the quality of dairy products.

Antibiotic resistance of ESKAPE group-microorganisms in health institutions from Hermosillo and Ciudad Obregón, Sonora, México.

Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. are microorganisms referred as the ESKAPE group pathogens. These microorganisms have generated great concern in health institutions around the world since most of them have resistance to multiple antibiotics and cause most infections associated with healthcare, as well as community infections. The aim of this study was the analysis of antibiotic resistance in microorganisms of the ESKAPE group, recovered from clinical samples in 11 health institutions from Hermosillo and Ciudad Obregón in the State of Sonora, México, during the period from 2019 to 2020. A cross-sectional, descriptive, observational, and temporality epidemiological study was carried out. A comparative and statistical analysis of antibiotic resistance was carried out using the chi-square test, and small values were analyzed using Fisher's exact test p ≤ 0.05. All the ESKAPE group microorganisms showed significant differences in antibiotic resistance percentages between both cities. High resistance percentages for some antibiotics, like cephalosporins and ciprofloxacin were detected for Klebsiella pneumoniae and Acinetobacter baumannii.

New Biocides Based on N4-Alkylcytidines: Effects on Microorganisms and Application for the Protection of Cultural Heritage Objects of Painting.

The rapid increase in the antibiotic resistance of microorganisms, capable of causing diseases in humans as destroying cultural heritage sites, is a great challenge for modern science. In this regard, it is necessary to develop fundamentally novel and highly active compounds. In this study, a series of N4-alkylcytidines, including 5- and 6-methylcytidine derivatives, with extended alkyl substituents, were obtained in order to develop a new generation of antibacterial and antifungal biocides based on nucleoside derivatives. It has been shown that N4-alkyl 5- or 6-methylcytidines effectively inhibit the growth of molds, isolated from the paintings in the halls of the Ancient Russian Paintings of the State Tretyakov Gallery, Russia, Moscow. The novel compounds showed activity similar to antiseptics commonly used to protect works of art, such as benzalkonium chloride, to which a number of microorganisms have acquired resistance. It was also shown that the activity of N4-alkylcytidines is comparable to that of some antibiotics used in medicine to fight Gram-positive bacteria, including resistant strains of Staphylococcus aureus and Mycobacterium smegmatis. N4-dodecyl-5- and 6-methylcytidines turned out to be the best. This compound seems promising for expanding the palette of antiseptics used in painting, since quite often the destruction of painting materials is caused by joint fungi and bacteria infection.

From remote to urbanized: Dispersal of antibiotic-resistant bacteria under the aspect of anthropogenic influence

Antibiotic resistance is a growing global concern, but our understanding of the spread of resistant bacteria in remote regions remains limited. While some level of intrinsic resistance likely contributes to reduced susceptibility to antimicrobials in the environment, it is evident that human actions, particularly the (mis)use of antibiotics, play a significant role in shaping the environmental resistome, even in seemingly distant habitats like glacier ice sheets.Our research aims to bridge this knowledge gap by investigating the direct influence of human activities on the presence of antibiotic-resistant bacteria in various habitats. To achieve a comprehensive assessment of anthropogenic impact across diverse and seemingly isolated sampling sites, we developed an innovative approach utilizing Corine Land Cover data and heatmaps generated from sports activity trackers. This method allowed us to make meaningful comparisons across relatively pristine environments.Our findings indicate a noteworthy increase in culturable antibiotic-resistant bacteria with heightened human influence, as evidenced by our analysis of glacier, snow, and lake water samples. Notably, the most significant concentrations of antibiotic-resistant and multidrug-resistant microorganisms were discovered in two highly impacted sampling locations, namely the Tux Glacier and Gas Station Ellmau.

Сhronic rhinosinusitis in adult patients with cystic fibrosis receiving CFTR modulators

Cystic fibrosis-associated chronic rhinosinusitis (CRS) is a separate form of CRS that progresses gradually over the course of patient’s life and worsens with age. The reasons for this are the mechanical congestion of mucus in the paranasal sinuses and the persistence of colonies of pathogenic antibiotic-resistant microorganisms. Therapy with CFTR modulators has resulted in a significant reduction in the severity of CRS. The nature of these changes and the dynamics in the microbial landscape of the upper respiratory tract are not sufficiently explored.Aim of the article is to highlight various aspects of the impact of CFTR modulators on the course of CRS in adult patients with cystic fibrosis (CF) based on literature data and a number of our own clinical observations. The article presents a series of clinical cases of CRS in adult CF patients treated with CFTR modulators for different periods of time.Conclusion. During targeted therapy with CFTR modulators, the symptoms of CRS are reversed due to the restoration of normal rheological properties of nasal secretions, the clinical picture improves, and the severity of CRS decreases. However, this type of treatment has no direct effect on the microbial landscape of the respiratory tract and requires additional interventions in the form of local and systemic antibacterial therapy. Therapy with CFTR modulators alters the course of CF in the nasal cavity, as well as in the pharynx and larynx.

Analysis of Plasmid-Mediated Quinolone Resistance (PMQR) Genes Among Escherichia coli Strains Isolated from Patients with Urinary Tract Infection in Eastern Turkey

Aim: Urinary tract infections are a common occurrence worldwide, with females being more susceptible than males.  Infections can manifest as asymptomatic bacteriuria or more severe forms such as sepsis. This study aims to analyse the plasmid-mediated quinolone resistance genes of Escherichia coli (E. coli) responsible for causing urinary tract infections.
 Material and Method: Microbiological evaluation was conducted using conventional culture method, API 20E (API-bioMérieux, France), antibiotic susceptibility tests, and polymerase chain reaction (PCR).
 Results: During the study period, 145 E. coli strains were collected from 96 (66.2%) outpatients and 49 (33.8%) hospitalised patients with urinary tract infections (UTI). The resistance rates of E. coli strains to quinolone antibiotics were as follows: nalidixic acid in 102 strains (70.3%), ciprofloxacin in 96 strains (66.2%), ofloxacin in 73 strains (50.3%), gatifloxacin in 47 strains (32.4%), levofloxacin in 41 strains (28.3%) and moxifloxacin in 32 (22%) strains. Based on the PCR test results, it was found that 80% (116) of the isolates carried at least one PMQR gene. Furthermore, 31.9% (37/116) of the isolates were found to carry two or three PMQR markers simultaneously.
 Discussion and Conclusion: The objective of this study was to establish the prevalence of quinolone resistance among E. coli strains isolated from patients with UTI. To control the high rate of spread of antibiotic-resistant microorganisms, it is crucial for all healthcare facilities to implement more careful management of antibiotic use and adhere to procedures set by infection control programmes.

Prominent Classes of Antibiotics and their Mechanism of Resistance against Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a prominent pathogenic, antibiotic-resistant microorganism that contains a variety of virulent characteristics having the capacity to develop tolerance to several major classes of antibiotics. The ongoing creation of clones enhances this potential, transforming S. aureus into an “Anti-Infective.” MRSA has started to rise as a Hospital-Acquired MRSA, but due to evolution, new strains of MRSA have been discovered throughout the past several years. The new strains of MRSA as Community-Acquired MRSA, and Livestock-Associated MRSA are infecting the patients despite preexisting medical conditions, being as susceptible to any treatment. The continuous expansion of MRSA is still ongoing. The main goal of this article is to improve reading comprehension of MRSA by studying the prominent classes of antibiotics and their mechanism of resistance which are now susceptible or getting susceptible to the MRSA.

Light, Copper, Action: Visible-Light Illumination Enhances Bactericidal Activity of Copper Particles.

Bacteria are an old concern to human health, as they are responsible for nosocomial infections, and the number of antibiotic-resistant microorganisms keeps growing. Copper is known for its intrinsic biocidal properties, and therefore, it is a promising material to combat infections when added to surfaces. However, its biocidal properties in the presence of light illumination have not been fully explored, especially regarding the use of microsized particles since nanoparticles have taken over all fields of research and subjugated microparticles despite them being abundant and less expensive. Thus, the present work studied the bactericidal properties of metallic copper particles, in microscale (CuMPs) and nanoscale (CuNPs), in the absence of light and under white LED light illumination. The minimum bactericidal concentration (MBC) of CuMPs against Staphylococcus aureus that achieved a 6-log reduction was 5.0 and 2.5 mg mL-1 for assays conducted in the absence of light and under light illumination, respectively. Similar behavior was observed against Escherichia coli. The bactericidal activity under illumination provided a percentage increase in log reduction values of 65.2% for S. aureus and 166.7% for E. coli when compared to the assays under dark. This assay reproduced the testing CuNPs, which showed superior bactericidal activity since the concentration of 2.5 mg mL-1 promoted a 6-log reduction of both bacteria even under dark. Its superior bactericidal activity, which overcame the effect of illumination, was expected once the nanoscale facilitated the interaction of copper within the surface of bacteria. The results from MBC were supported by fluorescence microscopy and atomic absorption spectroscopy. Therefore, CuMPs and CuNPs proved to have size- and dose-dependent biocidal activity. However, we have shown that CuMPs photoactivity is competitive compared to that of CuNPs, allowing their application as a self-cleaning material for disinfection processes assisted by conventional light sources without additives to contain the spread of pathogens.

Characterization of harmful gases and bioaerosols of pig farms: a review of the existing literature

From the ecological and economic point of view, intensive pig farming is drawing more and more attention due to the appearance of harmful substances, which significantly increases the risks of air, water and soil pollution. In addition, the optimal criteria for the content of harmful gases, dust and microorganisms in the environment of pig farms are currently not clearly defined. In order to better understand the interaction of harmful emissions and aerosols, the article reviews data from the literature on their main components, concentrations, and interactions. The results showed that the main pollutants in pig farming are harmful gases (ammonia (NH3), carbon dioxide (CO2), methane (CH4), nitrogen oxide (N2O), hydrogen sulfide (H2S), which are released from manure. The presence of even small concentrations of harmful gases in farm air can cause respiratory and cardiovascular system disorders not only in animals, but also in humans. Along with harmful gases, it is important to control the emission of solid particles and dust from livestock premises, which can form aerosols. Microbial aerosols in pig houses contain bacteria, fungi, viruses, which mainly come from the animals themselves, manure or service personnel. The bioaerosol includes the Firmicutes and Bacteroidetes bacterial divisions and their derivatives. In addition, the content of potentially dangerous bacteria in the bioaerosol can reach up to 40 %. A major concern causes the presence of a large number of antibiotic-resistant microorganisms in the air of these farms (including MRSA). The existing strategies and methods to combat these problems are still imperfect and need to be refined. Currently, the interaction of harmful gases, dust, solid particles and microorganisms is not taken into account, which can increase the toxic effect of each other on the animal's body. Therefore, there is a need for a better understanding of these interactions in order to improve the strategy for improving the microclimate conditions by correcting the microbiota, finding and developing biological preparations that contain natural bacteria capable of neutralizing odors and disinfecting livestock premises.

Antimicrobial photodynamic therapy with Brazilian green propolis controls intradermal infection induced by methicillin-resistant Staphylococcus aureus and modulates the inflammatory response in a murine model.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of skin and soft tissue infections worldwide. This microorganism has a wide range of antibiotics resistance, a fact that has made the treatment of infections caused by MRSA difficult. In this sense, antimicrobial photodynamic therapy (aPDT) with natural products has emerged as a good alternative in combating infections caused by antibiotic-resistant microorganisms. The objective of the present study was to evaluate the effects of aPDT with Brazilian green propolis against intradermal MRSA infection in a murine model. Initially, 24 Balb/c mice were infected intradermally in the ears with 1.5 × 108 colony-forming units of MRSA 43300. After infection, they were separated into 4 groups (6 animals per group) and treated with the vehicle, only Brazilian green propolis, only blue LED light or with the aPDT protocol (Brazilian green propolis + blue LED light). It was observed in this study that aPDT with Brazilian green propolis reduced the bacterial load at the site of infection. Furthermore, it was able to inhibit weight loss resulting from the infection, as well as modulate the inflammatory response through greater recruitment of polymorphonuclear cells/neutrophils to the infected tissue. Finally, aPDT induced an increase in the cytokines IL-17A and IL-12p70 in the draining retromaxillary lymph node. Thus, aPDT with Brazilian green propolis proved to be effective against intradermal MRSA infection in mice, reducing bacterial load and modulating the immune response in the animals. However, more studies are needed to assess whether such effects are repeated in humans.