Poly(sebacic acid) microparticles loaded with azithromycin as potential pulmonary drug delivery system: Physicochemical properties, antibacterial behavior, and cytocompatibility studies

Recurrent bacterial infections are a common cause of death for patients with cystic fibrosis and chronic obstructive pulmonary disease. Herein, we present the development of the degradable poly(sebacic acid) (PSA) microparticles loaded with different concentrations of azithromycin (AZ) as a potential powder formulation to deliver AZ locally to the lungs. We characterized microparticle size, morphology, zeta potential, encapsulation efficiency, interaction PSA with AZ and degradation profile in phosphate buffered saline (PBS). The antibacterial properties were evaluated using the Kirby-Bauer method against Staphylococcus aureus. Potential cytotoxicity was evaluated in BEAS-2B and A549 lung epithelial cells by the resazurin reduction assay and live/dead staining. The results show that microparticles are spherical and their size, being in the range of 1-5 μm, should be optimal for pulmonary delivery. The AZ encapsulation efficiency is nearly 100 % for all types of microparticles. The microparticles degradation rate is relatively fast - after 24 h their mass decreased by around 50 %. The antibacterial test showed that released AZ was able to successfully inhibit bacteria growth. The cytotoxicity test showed that the safe concentration of both unloaded and AZ-loaded microparticles was equal to 50 μg/ml. Thus, appropriate physicochemical properties, controlled degradation and drug release, cytocompatibility, and antibacterial behavior showed that our microparticles may be promising for the local treatment of lung infections.

Sonochemical Deposition of Gentamicin Nanoparticles at the PCV Tracheostomy Tube Surface Limiting Bacterial Biofilm Formation

BACKGROUND

The use of nanotechnology in the production of medical equipment has opened new possibilities to fight bacterial biofilm developing on their surfaces, which can cause infectious complications. In this study, we decided to use gentamicin nanoparticles. An ultrasonic technique was used for their synthesis and immediate deposition onto the surface of tracheostomy tubes, and their effect on bacterial biofilm formation was evaluated.

METHODS

Polyvinyl chloride was functionalized using oxygen plasma followed by sonochemical formation and the embedment of gentamicin nanoparticles. The resulting surfaces were characterized with the use of AFM, WCA, NTA, FTIR and evaluated for cytotoxicity with the use of A549 cell line and for bacterial adhesion using reference strains of S. aureus (ATCC^® 25923™) and E. coli (ATCC^® 25922™).

RESULTS

The use of gentamicin nanoparticles significantly reduced the adhesion of bacterial colonies on the surface of the tracheostomy tube for S. aureus from 6 × 10⁵ CFU/mL to 5 × 10³ CFU/mL and for E. coli from 1.655 × 10⁵ CFU/mL to 2 × 10¹ CFU/mL, and the functionalized surfaces did not show a cytotoxic effect on A549 cells (ATTC CCL 185).

CONCLUSIONS

The use of gentamicin nanoparticles on the polyvinyl chloride surface may be an additional supporting method for patients after tracheostomy in order to prevent the colonization of the biomaterial by potentially pathogenic microorganisms.

Porous Zirconia Scaffolds Functionalized with Calcium Phosphate Layers and PLGA Nanoparticles Loaded with Hydrophobic Gentamicin

Implant-related infections are a worldwide issue that is considered very challenging. Conventional therapies commonly end up failing; thus, new solutions are being investigated to overcome this problem. The in situ delivery of the drug at the implant site appears to be more sufficient compared to systemic antibiotic therapy. In this study, we manufactured porous zirconia scaffolds using the foam replication method. To improve their overall bioactivity, they were coated with a calcium phosphate (CaP) layer containing antibiotic-loaded degradable polymer nanoparticles (NPs) obtained by the double emulsion method to achieve the antibacterial effect additionally. Encapsulation efficiency (EE) and drug loading (DL) were superior and were equal to 99.9 ± 0.1% and 9.1 ± 0.1%, respectively. Scaffolds were analyzed with scanning electron microscopy, and their porosity was evaluated. The porosity of investigated samples was over 90% and resembled the microstructure of spongy bone. Furthermore, we investigated the cytocompatibility with osteoblast-like MG-63 cells and antimicrobial properties with Staphylococcus aureus. Scaffolds coated with a CaP layer were found non-toxic for MG-63 cells. Moreover, the presence of antibiotic-loaded nanoparticles had no significant influence on cell viability, and the obtained scaffolds inhibited bacteria growth. Provided processes of fabrication of highly porous zirconia scaffolds and surface functionalization allow minimizing the risk of implant-related infection.

Stethoscopes or Maybe "Bacterioscopes" - Is hand Hygiene Solely Capable of Preventing Hospital-Associated Infections?

The stethoscope remains an indispensable diagnostic tool for medical students. Improper stethoscope hygiene may cause bacterial infections, including hospital-associated infections (HAIs), which challenge the Polish medical system. The study's main objective was to evaluate the hygiene habits declared by medical students. Moreover, microbiological control with the characteristics of potentially pathogenic microorganisms was performed. The study included 66 medical students from the Faculty of Medicine at the Jagiellonian University Medical College in Cracow, Poland. The participants filled in an anonymous questionnaire. Stethoscope contamination was assessed through isolation, identification, testing of antibiotic resistance, and clonality of the isolates bacterial pathogens. The survey showed that only 30.3% of students cleaned their stethoscopes after each patient, and 1.5% never did this. Of the 66 stethoscopes tested, 100% were positive for bacterial growth. Staphylococcus spp. was the most frequently isolated contaminant (50.5%). The questionnaire results demonstrated the necessity of the validated procedures for cleaning the stethoscopes. Stethoscopes used by medical students are contaminated with numerous bacterial species, including multidrug-resistant organisms. The clonal structure of the MRSA and MRSE populations acquired from stethoscopes has been demonstrated. Our results confirm the possibility that these medical devices mediate the spread of hazardous pathogens in the hospital environment. Practical exercises are essential to forming the correct hygiene habits involving stethoscopes, which enable practicing and checking the correctness of the established skills.

Insight in Superiority of the Hydrophobized Gentamycin in Terms of Antibiotics Delivery to Bone Tissue

Bone infections are a serious problem to cure, as systemic administration of antibiotics is not very effective due to poor bone vascularization. Therefore, many drug delivery systems are investigated to solve this problem. One of the potential solutions is the delivery of antibiotics from poly(L-actide-co-glycolide) (PLGA) nanoparticles suspended in the gellan gum injectable hydrogel. However, the loading capacity and release kinetics of the system based on hydrophilic drugs (e.g., gentamycin) and hydrophobic polymers (e.g., PLGA) may not always be satisfying. To solve this problem, we decided to use hydrophobized gentamycin obtained by ion-pairing with dioctyl sulfosuccinate sodium salt (AOT). Herein, we present a comparison of the PLGA nanoparticles loaded with hydrophobic or hydrophilic gentamycin and suspended in the hydrogel in terms of physicochemical properties, drug loading capacity, release profiles, cytocompatibility, and antibacterial properties. The results showed that hydrophobic gentamycin may be combined in different formulations with the hydrophilic one and is superior in terms of encapsulation efficiency, drug loading, release, and antibacterial efficacy with no negative effect on the NPs morphology or hydrogel features. However, the cytocompatibility of hydrophobic gentamycin might be lower, consequently more extensive study on its biological properties should be provided to evaluate a safe dose.

Microbiological analysis of tracheostomy tube biofilms and antibiotic resistance profiles of potentially pathogenic microorganisms

<b>Introduction:</b> In hospitalized patients, tracheostomy tubes (TTs) are susceptible to colonization by biofilm- producing potentially pathogenic microorganisms (PPMs). Contact with TTs, which are situated in a critical region of the body with enormous microbial exposure, may lead to the emer-gence of resistant respiratory infections.</br></br> <b>Objective:</b> Our study aimed to isolate and identify Gram-positive and Gram-negative PPMs, mark their antibiotic resistance and determine the bacteriological pattern of the biofilm colonizing the TTs. </br></br> <b>Methods:</b> The study was conducted on 45 tracheostomy tubes obtained from 45 hospitalized adult patients with tracheostomy with intubation periods ranging from 1 to 28 days. Tracheal aspirates (TA) obtained from polyvinyl chloride (PVC) TTs were used for the analysis. Bacteria in biofilms were identified by standard microbiological techniques, tested for antibiotic resistance and phenotypic resistance according to the EUCAST guidelines and visualized by SEM.</br></br> <b>Results:</b> Out of 45 TTs, 100% were found to be positive in bacterial cultures with 58 PPM isolates (10 spe-cies) correlating well with the SEM findings. Overall, 72% of isolates were Gram-negative bacilli, followed by Gram-positive cocci (28%). Staphylococcus aureus was the predominant bacterium (identified in 35.5% of patients), followed by Klebsiella pneumoniae (identified in 23.8%). Among the Gram-negative PPMs, 50% of isolates were identified as multidrug-resistant (MDR), 8.6% as extremely drug-resistant (XDR) and 5.2% were pandrug-resistant (PDR).</br></br><b>Conclusions:</b> Our study showed a rapid colonization of the TT surface by biofilm- producing PPMs. Patients with tracheosto- mies, also those with non-infectious conditions, were mainly colonized with highly re-sistant bacteria.

Molecular Characteristic, Antibiotic Resistance, and Detection of Highly Immunoreactive Proteins of Group B Streptococcus Strains Isolated From Urinary Tract Infections in Polish Adults

Group B streptococcus (GBS) is one of the uropathogens that causes urinary tract infections (UTIs). The aims of this article were molecular characterization, an analysis of antimicrobial susceptibility profiles, adherence to bladder endothelial cells, and the detection of immunoreactive proteins of 94 clinical strains of GBS isolated from adult Polish patients with UTI. Antibiotic susceptibilities were determined by disk diffusion. Serotyping and Alp family genes detection were studied using multiplex PCR. Genetic profiles were determined by pulsed-field gel electrophoresis. The adherence ability of the studied strains was estimated by incubation on human bladder microvascular endothelial cell line. Immunoreactive proteins were studied by immunoblotting. Antibiotic susceptibility investigation revealed that 22% of GBS strains were resistant to erythromycin, whereas 18% demonstrated resistance to clindamycin. cMLS_B was present in 76% of the resistant strains, M phenotype was detected in 14%, whereas iMLS_B was present for 10%. The most common serotype was serotype III (31%), followed by serotype V (27%), and serotype Ia (17%). The genes that dominated among other Alp genes were: epsilon (29%), alp2 (27%), and rib (23%). The most common co-occurring serotypes and Alp genes were: Ia and epsilon, III and rib, III and alp2, V and alp2, and V and alp3 (p < 0.001). The PFGE method showed high clonality for serotype V and cMLS_B (p < 001). The PFGE method showed high clonality for serotype V. Furthermore, this serotype was significantly associated with the cMLS_B phenotype (p < 0.001). The most common immunoreactive proteins demonstrated masses of 50 kDa and 45–47 kDa. Although examined GBS isolates showed high genetic diversity, immunoreactive proteins were common for most of the studied GBS isolates, which may indicate their conservation, and allows to consider them as potential immunodiagnostic markers. Although the examined GBS isolates showed high genetic diversity, immunoreactive proteins were shared by most of the studied GBS isolates. It may indicate their conservation, thus allowing to consider them as potential immunodiagnostic markers.

Biofilm Formation of Clinical Klebsiella pneumoniae Strains Isolated from Tracheostomy Tubes and Their Association with Antimicrobial Resistance, Virulence and Genetic Diversity

(1) Background: Due to the commonness of tracheotomy procedures and the wide use of biomaterials in the form of tracheostomy tubes (TTs), the problem of biomaterial-associated infections (BAIs) is growing. Bacterial colonization of TTs results in the development of biofilms on the surface of biomaterials, which may contribute to the development of invasive infections in tracheostomized patients. (2) Methods: Clinical strains of K. pneumoniae, isolated from TTs, were characterized according to their ability to form biofilms, as well as their resistance to antibiotics, whether they harbored ESβL genes, the presence of selected virulence factors and genetic diversity. (3) Results: From 53 patients, K. pneumoniae were detected in 18 of the TTs examined, which constituted 34% of all analyzed biomaterials. Three of the strains (11%) were ESβL producers and all had genes encoding CTX-M-1, SHV and TEM enzymes. 44.4% of isolates were biofilm formers, SEM demonstrating that K. pneumoniae formed differential biofilms on the surface of polyethylene (PE) and polyvinyl chloride (PVC) TTs in vitro. A large range of variation in the share of fimbrial genes was observed. PFGE revealed sixteen genetically distinct profiles. (4) Conclusions: Proven susceptibility of TT biomaterials to colonization by K. pneumoniae means that the attention of research groups should be focused on achieving a better understanding of the bacterial pathogens that form biofilms on the surfaces of TTs. In addition, research efforts should be directed at the development of new biomaterials or the modification of existing materials, in order to prevent bacterial adhesion to their surfaces.

Clonal Dissemination of KPC-2, VIM-1, OXA-48-Producing Klebsiella pneumoniae ST147 in Katowice, Poland

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an important bacterium of nosocomial infections. In this study, CRKP strains, which were mainly isolated from fecal samples of 14 patients in three wards of the hospital in the Silesia Voivodship, rapidly increased from February to August 2018. Therefore, we conducted microbiological and molecular studies of the CRKP isolates analyzed. Colonized patients had critical underlying diseases and comorbidities; one developed bloodstream infection, and five died (33.3%). Antibiotic susceptibilities were determined by the E-test method. A disc synergy test confirmed carbapenemase production. CTX-Mplex PCR evaluated the presence of resistance genes bla_CTX-M-type, bla_CTX-M-1, bla_CTX-M-9, and the genes bla_SHV, bla_TEM, bla_KPC-2, bla_NDM-1, bla_OXA-48, bla_IMP, and bla_VIM-1 was detected with the PCR method. Clonality was evaluated by Multi Locus Sequence Typing (MLST) and Pulsed Field Gel Electrophoresis (PFGE). Six (40%) strains were of XDR (Extensively Drug-Resistant) phenotype, and nine (60%) of the isolates exhibited MDR (Multidrug-Resistant) phenotype. The range of carbapenem minimal inhibitory concentrations (MICs, μg/mL) was as follows doripenem (16 to >32), ertapenem (> 32), imipenem (4 to > 32), and meropenem (> 32). PCR and sequencing confirmed the bla_CTX-M-15, bla_KPC-2, bla_OXA-48, and bla_VIM-1 genes in all strains. The isolates formed one large PFGE cluster (clone A). MLST assigned them to the emerging high-risk clone of ST147 (CC147) pandemic lineage harboring the bla_OXA-48 gene. This study showed that the K. pneumoniae isolates detected in the multi-profile medical centre in Katowice represented a single strain of the microorganism spreading in the hospital environment.

Non-cytotoxic, temperature-responsive and antibacterial POEGMA based nanocomposite coatings with silver nanoparticles

Non-cytotoxic, temperature-responsive and antibacterial polymer/silver nanoparticles nanocomposite coatings with prolonged action.

Evidence for Infections by the Same Strain of Beta 2-toxigenic Clostridium perfringens Type A Acquired in One Hospital Ward

This study conducts a comparative phenotypic and genetic analysis of C. perfringens strains isolated from two patients hospitalized at the same time in 2017 in the surgical ward of the Provincial Specialist Hospital in Włocławek (Kujawsko-Pomorskie Province) who developed necrotizing soft tissue infections (NSTI). To explain the recurring cases of this infection, a comparative analysis was performed for these strains and the ones originating from infections recorded at the same hospital in three patients with gas gangrene in 2015. The two C. perfringens isolates studied in 2017 (8554/M/17 from patient No. 1 and 8567/M/17 from patient No. 2) had identical biochemical profiles. A comparison of research results using multiplex PCR from 2017 with a genetic analysis of strains from 2015 enabled us to demonstrate that the strains currently studied have the genes encoding the same toxins (α and β2) as the two strains analyzed in 2015: no. 7143 (patient No. 3) and no. 7149 (patient No. 2). A comparative analysis of the strain profiles obtained with pulsed-field gel electrophoresis (PFGE) in 2017 with the results from 2015 has found one identical and genetically unique restriction profile, corresponding to one clone of C. perfringens comprising of two strains: no. 8567/M/17 (patient No. 2 in 2017) and no. 7143 (patient No. 3 in 2015). The epidemiological data and detailed analysis of the course of both events suggest that this clone of C. perfringens possibly survived in adverse conditions of the external environment in the operating block of this hospital for many months.

"Command" surfaces with thermo-switchable antibacterial activity

In the presented work "smart" antibacterial surfaces based on silver nanoparticles (AgNPs) embedded in temperature-responsive poly(di(ethylene glycol)methyl ether methacrylate) - (POEGMA188) as well as poly(4-vinylpyridine) - (P4VP) coatings attached to a glass surface were successfully prepared. The composition, thickness, morphology and wettability of the resulting coatings were analyzed using ToF-SIMS, XPS, EDX, ellipsometry, AFM, SEM and CA measurements, respectively. Temperature-switched killing of the bacteria was tested against Escherichia coli ATCC 25922 (representative of Gram-negative bacteria) and Staphylococcus aureus ATCC 25923 (representative of Gram-positive bacteria) at 4 and 37 °C. In general at 4 °C no significant difference was observed between the amounts of bacteria accounted on the grafted brush coatings and within the control sample. In contrast, at 37 °C almost no bacteria were visible for temperature-responsive coating with AgNPs, whereas the growth of bacteria remains not disturbed for "pure" coating, indicating strong temperature-dependent antibacterial properties of AgNPs integrated into brushes.

Gas Gangrene of Different Origin Associated with Clostridium perfringens Type A in Three Patients Simultaneously Hospitalized in a Single Department of Orthopedics and Traumatology in Poland

The objective of the study was to perform a comparative analysis of phenotypic and genetic similarity, determination of resistance profiles, detection of toxin-encoding genes and molecular typing of Clostridium perfringens isolates originating from patients with gas gangrene. The study encompassed three patients with a clinical and microbiological diagnosis of gas gangrene who were hospitalized in one of the hospitals of the Kujawsko-Pomorskie province in the same period of time between 8^th April 2015 and 20^th April 2015. The three C. perfringens isolates studied had identical biochemical profiles. Two isolates had identical resistance patterns, while the third presented a different profile. Using the multiplex PCR method, all isolates showed the presence of cpa gene encoding α-toxin; furthermore, the presence of the cpb2 gene encoding β2-toxin was confirmed in two isolates. Genotyping with the use of pulsed field gel electrophoresis (PFGE) indicated that the isolates originating from the three studied patients represent three genetically different restrictive patterns which corresponded to three different clones - clone A, clone B and clone C. As a result of the study, it is possible to conclude that the studied patients simultaneously hospitalized in a single Department of Orthopedics and Traumatology developed three different endogenous infections.

A study of the effects of therapeutic doses of ionizing radiation in vitro on Lactobacillus isolates originating from the vagina - a pilot study

BACKGROUND

Ionizing radiation is used as a therapeutic option in the treatment of certain neoplastic lesions located, among others, in the pelvic region. The therapeutic doses of radiation employed often result in adverse effects manifesting themselves primarily in the form of genital tract infections in patients or diarrhea. The data available in the literature indicate disorders in the microbial ecosystem caused by ionizing radiation, which leads to the problems mentioned above. In the present study, we examined the influence of ionizing radiation on 52 selected strains of bacteria: Lactobacillus crispatus, L. fermentum, L. plantarum, L. reuteri, L. acidophilus L. amylovorus, L. casei, L. helveticus, L. paracasei, L. rhamnosus, L. salivarius and L. gasseri. This collection of Lactobacillus bacteria isolates of various species, obtained from the genital tract and gastrointestinal tract of healthy women, was tested for resistance to therapeutic doses of ionizing radiation.

RESULTS

The species studied, were isolated from the genital tract (n = 30) and from the anus (n = 22) of healthy pregnant women. Three doses of 3 Gy (fractionated dose) and 50 Gy (total dose of the whole radiotherapy cycle) were applied. The greatest differences in survival of the tested strains in comparison to the control group (not subjected to radiation) were observed at the dose of 50 Gy. However, the results were not statistically significant. Survival decrease to zero was not demonstrated for any of the tested strains.

CONCLUSIONS

Therapeutic doses of radiation do not affect the Lactobacillus bacteria significantly.

The general status of patients and limited physical activity as risk factors of Methicillin-resistant Staphylococcus aureus occurrence in long-term care facilities residents in Krakow, Poland

Background

The aim of this study was to investigate the epidemiology and resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolates from long-term care facilities (LTCF) residents and to analyze the potential risk factors for MRSA occurrence, defined as MRSA colonization and/or infection.

Methods

Point prevalence (PPS) and prospective incidence continuous study (CS) was carried out on a group of 193 residents in 2009-2010.

Results

Overall MRSA occurred (with or without infection) among 17.6% of residents. There was 16 cases of infections with SA aetiology, of which 10 (58.8%) were caused by MRSA. The MRSA prevalence in PPS was 12.9%, in CS infection incidence rate was 5.2%. Factors associated with MRSA occurrence were: general status of patients, limited physical activity, wound infections (odds ratio, OR 4.6), ulcers in PPS (OR 2.1), diabetes (OR 1.6), urinary catheterization (OR 1.6) and stool incontinence (OR 1.2).

Conclusions

Our data indicate a need for screening of MRSA before hospitalization or transfer to rehabilitation centres, especially in a group of residents with limitations in physical activity – i.e. with the highest risk of MRSA. Results also suggest the need for contact precautions in patients with high risk of MRSA occurrence, only. Focus on the high-risk population might be a solution for the cost-effective surveillance.

Carriage of group B streptococci in pregnant women from the region of Krakow and their antibiotic resistance in the years 2008-2012

The aim of the study was a retrospective analysis of the frequency of group B streptococci (Streptococcus agalactaie; GBS) carriage in pregnant women from the region of Krakow, together with an analysis of their drug resistance, carried out between 2008-2012. The study included 3363 pregnant women between 35 and 37 weeks of gestation, studied in accordance with the guidelines of the Polish Gynecological Society (2008). A high percentage of pregnant women who are carriers of group B streptococci was demonstrated. Each year covered by the study, it was in the range of 25-30%, with an average value equal to 28%. The results confirm the need for taking swabs from both the vagina and anus, since 15% of GBS-positive patients showed only rectal carriage. High percentage of isolates resistant to erythromycin was detected, which ranged from 22% to 29%, with an average value equal to 25%, as well as a high proportion of isolates resistant to clindamycin being 17-25%, with an average of 20%. The results indicate the need to standardize the methodology of collecting samples for GBS testing and introduce microbiological diagnostic standards in all gynecological and obstetric centers in Poland, in order to carry out a detailed epidemiological analysis in our country.