Antibiotics Vancomycin Research Articles

Potent Rifampicin derivatives can clear MRSA infections at single low doses when concomitantly dosed with Vancomycin.

For a number of years, antimicrobial resistance (AMR) has been a critical issue for humanity. Drug discovery efforts have been very limited and the spread of bacterial pathogens has over-run our traditional arsenal of antibiotics. Bacteria can involve to evade compounds that can halt their rapid growth. The authors have discovered a potent macrocycle derivative that when dosed concomitantly with the standard of care (SOC) antibiotic vancomycin, can clear methicillin resistant Staphylococcus aureus (MRSA) infections. In addition, we have probed the lead compounds in Salmonella typhimurium bacterial strains. In vitro, in vivo, and ADME data have been included to stress the virtues of this new antibiotic.

Multidrug Resistance in Enterococci Isolated from Cheese and Capable of Producing Benzalkonium Chloride-Resistant Biofilms.

This study aimed to investigate enterococci recovered from eight Portuguese cheeses made with raw ewe's milk, regarding antibiotic resistance, virulence genes, minimum inhibitory concentration (MIC) of benzalkonium chloride (BAC), biofilm formation capacity, and biofilm eradication (MBEC) by BAC. Antimicrobial resistance against seven antibiotics of five groups was evaluated using the disk diffusion method. The presence of the genes that encode resistance to the antibiotics penicillin (blaZ), erythromycin (ermA, ermB, and ermC), vancomycin (vanA and vanB), aminoglycoside (aac(6')-Ie-aph(2″)-Ia), and β-lactam (pbp5) and the genes that encode virulence factors, frsB, cylA, gelE, esp, and agg, were investigated via multiplex PCR. The susceptibility of planktonic cells to BAC was evaluated by the MIC and MBC values of the isolates, using the broth microdilution method. To assess the biofilm-forming ability and resistance of biofilms to BAC, biofilms were produced on stainless steel coupons, followed by exposure to BAC. The results showed a high resistance to the antibiotics vancomycin (87.5%), erythromycin (75%), tetracycline (50%), and penicillin (37.5%). Multidrug resistance was observed in 68.8% of the isolates. Genes encoding the virulence factors FrsB (frsB) and gelatinase E (gelE) were detected in all isolates. The esp and cylA genes were found in 56.3% and 37.5% of the isolates, respectively. All isolates exhibited a biofilm-forming ability, regardless of incubation time and temperature tested. However, after 72 h at 37 °C, E. faecium and E. faecalis biofilms showed significant differences (p ≤ 0.05). Although most isolates (62.5%) were susceptible to BAC (MIC ≤ 10 mg/L), biofilms of the same isolates were, generally, resistant to the higher concentration of BAC (80 mg/mL) tested. This study using Enterococcus isolates from a ready-to-eat food, such as cheese, reveals the high percentages of vancomycin resistance and multidrug resistance, associated with the presence of virulence genes, in isolates also capable of producing biofilms resistant to BAC, an important active ingredient of many disinfectants. These results emphasize the need for effective control measures to ensure the safety and quality of dairy products.

RavA-ViaA antibiotic response is linked to Cpx and Zra2 envelope stress systems in Vibrio cholerae.

The RavA-ViaA complex was previously found to sensitize Escherichia coli to aminoglycosides (AGs) in anaerobic conditions, but the mechanism is unknown. AGs are antibiotics known for their high efficiency against Gram-negative bacteria. In order to elucidate how the expression of the ravA-viaA genes increases bacterial susceptibility to aminoglycosides, we aimed at identifying partner functions necessary for increased tolerance in the absence of RavA-ViaA, in Vibrio cholerae. We show that membrane stress response systems Cpx and Zra2 are required in the absence of RavA-ViaA, for the tolerance to AGs and for outer membrane integrity. In the absence of these systems, the ∆ravvia strain's membrane becomes permeable to external agents such as the antibiotic vancomycin.

Impact of the new membrane-targeting lipoglycopeptide antibiotic MCC5145 on the treatment of bacteremic pneumococcal pneumonia in mice.

Bacteremic Streptococcus pneumoniae pneumonia is one of the most severe forms of invasive pneumococcal disease (IPD) and with particularly high case-fatality rates among the elderly and individuals with comorbidities, exacerbated by rising antibiotic resistance and time to initiation of therapy. Here, we examined the efficacy of the preclinical "vancapticin" glycopeptide MCC5145 against fulminant infection by S. pneumoniae serotype 2 strain D39 in a bioluminescent, neutropenic mouse model of bacteremic pneumonia. MCC5145 is a semisynthetic vancomycin derivative chemically modified at the C-terminus with a membrane-targeting motif designed to preferentially bind the anionic bacterial surface. We show that similar to vancomycin, subcutaneous administration of MCC5145 to mice 1 day after intranasal infection with a bioluminescent derivative of S. pneumoniae D39 elicited time and concentration-dependent reduction in total flux in the lungs and blood. Together, our finding supports the further development of MCC5145 as a potential new treatment option for pneumonia and/or bacteremic pneumonia in clinical settings, particularly for immunocompromised individuals. IMPORTANCE S. pneumoniae (the pneumococcus) causes severe community acquired lung and blood infection, especially among the elderly and people with underlying medical conditions and/or weakened immune systems. The rising incidence of antibiotic resistance and delays between diagnosis of infection and commencement of effective therapy make treatment difficult and result in high mortality rates. In this work, we show that a new derivative (MCC5145) of an existing antibiotic (vancomycin) rapidly eradicated lethal pneumococcal challenge from the lungs and blood of mice with a suppressed immune system. Our findings support that MCC5145 is a promising option for the treatment of lung and blood infections caused by the pneumococcus at point-of-care settings, particularly for the elderly and individuals with a weakened immune system.

Vitex negundo and Euphorbia milii leaf extracts aided green synthesis of copper oxide nanostructures for effective inactivation of pathogenic bacteria

A facile and green route was followed to synthesize copper oxide (CuO) nanostructures using Vitex negundo and Euphorbia milii leaf extracts. Structural, elemental, chemical, spectral and morphological features of the CuO nanostructures were determined by XRD, EDS, FTIR spectroscopy, UV–Vis spectrophotometer and FESEM, respectively. The CuO nanostructures disclosed considerably higher antibacterial activity against selected Gram-positive and Gram-negative pathogenic bacteria over commercial antibiotic (Vancomycin). This enhanced antibacterial activity could be credited to the generation of more ROS associated with oxygen vacancy and size of the CuO nanostructures. Particularly, hierarchical CuO nanoparticles/nanorods prepared using V. negundo leaf extract exhibited the highest antibacterial activity due to their lower size range.

Successful antibiotic management of Staphylococcus epidermidis endophthalmitis after implantable collamer lens implantation

PurposeWe report a case of successful medical management of endophthalmitis post implantable collamer lens (ICL) culture-positive of Staphylococcus epidermidis.Observations: A 18-year-old female presented with decreased visual acuity in the left eye 20 days after ICL implantation. A diagnosis of postoperative endophthalmitis was made based on examination and ultrasonography. A vitreous tap was taken, and intravitreal antibiotics (vancomycin 1 mg/0.1ml and ceftazidime 2 mg/0.1ml) were administered twice (every 72 h), and peribulbar injection of triamcinolone acetonide after four days of the second intravitreal injection. The vitreous culture was confirmed for Staphylococcus epidermidis. The endophthalmitis was resolved, and visual acuity improved from 6/20 to 12/20 on day 7 and 22/20 on day 38. This is the first successful medical resolution of Staphylococcus epidermidis endophthalmitis post ICL surgery without ICL explantation and vitrectomy in the V4c model.Conclusions and importance: In antibiotic therapy, the excellent compliance and close follow-up of this endophthalmitis patient enabled careful postoperative surveillance on the effect of antibiotic therapy, avoiding the removal of the ICL or the loss of the integrity of the eye. The risk of potential infectious endophthalmitis post-ICL surgery should be fully emphasized during preoperative counseling.

Case Report: Introduction of antibiotic releasing calcium sulfate bone void filler beads (Stimulan) for management of an infected cyst of the maxilla

Radicular cysts are the most common odontogenic cyst arising from epithelial cell rests of Malassez in the periodontal ligament and proliferate peripherally as a result of inflammation caused by infection at the root apices. They slowly grow apically causing bone resorption and displacement of the adjacent teeth which radiographically is seen as a radiolucent unilocular lesion. Management of such bone defects can be done by using various bone graft substitutes such as autogenous, allografts, xenografts and alloplasts. Taking account of the benefits of using synthetic bone graft substitutes, the following case represents the successful management of a radicular cyst, which includes endodontic treatment and cyst enucleation, chemical cauterization followed by introduction of antibiotic (Vancomycin) releasing calcium sulfate filler beads into the defect.

Effectiveness, safety, and cost of vancomycin and linezolid in Kuwait: A retrospective cohort study

BackgroundThe effectiveness, safety, and cost of vancomycin and linezolid for managing gram-positive bacterial infections in Kuwait are unknown. This study assessed the effectiveness, safety, and cost of vancomycin, teicoplanin and linezolid for managing gram-positive bacterial infections in Kuwait. Research design and methodsThis retrospective study included adult patients who were prescribed antibiotics (vancomycin, teicoplanin, and linezolid) for the treatment of gram-positive infections at five hospitals in Kuwait. Descriptive statistics were used to assess the effectiveness and safety outcomes. A cost analysis was performed on the patients hospitalised for gram-positive infections. ResultsAmong 116 patients, 42.2 % (n = 49) received glycopeptides (vancomycin [n = 45] and teicoplanin [n = 4]) or linezolid (n = 67). Clinical cure was achieved in 100 patients without significant intergroup differences (p = 0.34). Thrombocytopenia and acute kidney injury occurred in 19 and 20 patients (p = 0.82 and 0.96), respectively, and their incidence was similar with all the studied agents. The average cost per patient was USD 983.70. The estimated total direct medical costs were USD 894,570.6, the cost was highest for linezolid (USD 469,682.30) and vancomycin (USD 370,342.5), and lowest for teicoplanin (USD 20,799.9). ConclusionsGlycopeptides and linezolid were highly effective. Linezolid was the most frequently prescribed agent; its effectiveness and safety were similar according to the antibiotic class. However, treatment with linezolid and vancomycin were associated with considerable costs.

Influence of Bacterial Metabolites on the Systemic Antitumor Immune Response after Radiation Therapy in Combination with Immune Checkpoint Inhibitors

The gut microbiome influences the pathogenesis of many diseases and numerous medical therapies. In addition, it is well known that cancer patients are often treated with antibiotics during the course of their disease, which can lead to intestinal dysbiosis. Importantly, experimental and clinical studies have already shown that this has implications for tumor therapies and that immune-active bacterial metabolites can play a central mechanistic role. However, little is known about the influence of the bacterial microbiota or its metabolites on the outcome of radiotherapy (RT) in combination with immune checkpoint inhibitors (ICIs). We used a bilateral tumor model (MC38 tumor cells) to investigate the influence of the intestinal microbiota and selected bacterial metabolites on the abscopal effect after RT in combination with ICIs. In brief, RT (1 × 8 Gy) of the right tumor was performed 7 days after tumor induction, followed by application of α-CTLA4 or α-PD1 for three weeks. Antibiotics (ampicillin, neomycin, metronidazole, and vancomycin) or selected immune-activating metabolites were administered daily by gavage. We used bacterial metabolites that are described in the literature as having strong immune-modulating properties. In mice, combined treatment with different antibiotics had neither a significant effect on tumor growth of the irradiated tumor nor on tumor progression of the unirradiated tumor after RT in combination with α-CTLA4. In contrast, supplementation of specific bacterial metabolites had different effects depending on the type of ICI and the specific type of bacterial metabolite. Specifically, we identified bacterial metabolites that led to enhanced tumor progression of the unirradiated abscopal tumor after RT combined with ICIs, resulting in reduced survival rates. To the best of our knowledge, we are presenting here for the first-time experimental data on the influence of the intestinal microbiome on the abscopal effect after RT combined with ICIs. Our data clearly show that specific immune-active bacterial metabolites can negatively influence the abscopal effect after combined radioimmunotherapy. This implies the design of further experimental studies aimed at using specific strategies (e.g., antibiotics) to decimate certain gut bacteria and reduce the amount of certain bacterial metabolites to improve response rates after radioimmunotherapy.

Antisense inhibition of RNA polymerase α subunit of Clostridioides difficile.

Clostridioides difficile, the causative agent of antibiotic-associated diarrhea and pseudomembranous colitis, has emerged as a major enteric pathogen in recent years. Antibiotic treatment perturbs the gut microbiome homeostasis, which facilitates the colonization and proliferation of the pathogen in the host intestine. Paradoxically, the clinical repertoire for C. difficile infection includes the antibiotics vancomycin and/or fidaxomicin. The current therapies do not address the perturbed gut microbiome, which supports the recurrence of infection after cessation of antibiotic therapy. Peptide nucleic acids (PNAs) are novel alternatives to traditional antimicrobial therapy capable of forming strong and stable complexes with RNA and DNA, thus permitting targeted inhibition of specific genes. Here, we report a novel PNA that can target the RNA polymerase α subunit (rpoA) in C. difficile. The designed anti-rpoA construct inhibited clinical isolates of C. difficile (minimum inhibitory concentration values ranged between 4 and 8 µM) and exhibited bactericidal activity. Furthermore, silencing of the rpoA gene suppressed the expression of genes that encode virulence factors [toxin A (tcdA), toxin B (tcdB)] in C. difficile, and the gene that encodes the transcription factor stage 0 sporulation protein (spoOA). Interestingly, the efficacy of the designed PNA conjugate remained unaffected even when tested at different pH levels and against a high inoculum of the pathogen. The rpoA-TAT conjugate was very specific against C. difficile and did not inhibit members of the beneficial gut microflora. Taken altogether, our study confirms that the rpoA gene can be a promising narrow-spectrum therapeutic target to curb C. difficile infection. IMPORTANCE The widespread use of antibiotics can destroy beneficial intestinal microflora, opening the door for spores of Clostridioides difficile to run rampant in the digestive system, causing life-threatening diarrhea. Alternative approaches to target this deadly pathogen are urgently needed. We utilized targeted therapeutics called peptide nucleic acids (PNAs) to inhibit gene expression in C. difficile. Inhibition of the RNA polymerase α subunit gene (rpoA) by PNA was found to be lethal for C. difficile and could also disarm its virulence factors. Additionally, antisense inhibition of the C. difficile rpoA gene did not impact healthy microflora. We also propose a novel approach to manipulate gene expression in C. difficile without the need for established genetic tools.

Detection of Methicillin-resistant Staphylococcus aureus (MRSA) resistant to vancomycin and linezolid in bulk tank milk by E-test method

Staphylococcus aureus is considered a serious threat to public health, besides is one of the most common causes of subclinical mastitis in dairy cows. Therefore, especially methicillin-resistant Staphylococcus aureus (MRSA) is among the most critical reasons for antibiotic treatment. Monitoring the antibiotic resistance of MRSA from livestock animals and foods is of great significance. The E-test method is a suitable option for detecting antibiotics' minimum inhibition concentration (MIC) value because it is an easy and fast assay to perform. This study aimed to detect vancomycin, teicoplanin, and linezolid resistance of milk-borne 34 MRSA isolates with subclinical mastitis by the E-test method to determine MIC values. The study determined that 8.8% of MRSA isolates isolated from milk with subclinical mastitis were also resistant to vancomycin and 11.7% to linezolid, while none of the isolates were determined to be resistant to teicoplanin, according to EUCAST. The data obtained from the study reveal that the efficacy of vancomycin and linezolid antibiotics, which are commonly used against MRSA infections, are in danger. Especially before MRSA treatment, MIC values of antibiotics should be determined, and appropriate antibiotics should be used in effective doses.

Malakoplakia with aberrant ALK expression by immunohistochemistry: a case report

BackgroundMalakoplakia is a rare inflammatory disease of the urogenital tract. There have been no reports of malakoplakia expressing anaplastic lymphoma kinase (ALK) to date. Here, we present one case of malakoplakia with aberrant ALK expression by immunohistochemistry and discuss the clinical significance.Case presentationA 65-year-old Chinese woman with a history of diabetes presented with solid masses in the liver and kidney and elevated lesions on the mucosal surface of the colon. Right nephrectomy and partial liver resection were performed. Microscopically, sheets of histiocytes with poor intercellular adhesion were seen, with Michaelis–Gutmann bodies present in both the intracellular and extracellular interstitium. CD10-, CD68-, and CD163-positive cells were present, with Michaelis–Gutmann bodies confirmed by staining with Alcian blue, periodic acid-Schiff (PAS), periodic acid-Schiff with diastase, Von Kossa, and Prussian blue. Aberrant ALK1 and ALK (D5F3) expression was observed in the cytoplasm and nucleus of cells. However, ALK gene mutation was not detected by fluorescence in situ hybridization or whole exome next-generation sequencing. NGS revealed nine individual somatic gene mutations: GOT1L1, GLIS2, SPOUT1, TMEM97, MUC3A, NSD2, SFXN5, ADAD1 and RAD50. The significance of the somatic gene mutations detected in this study is not clear, and the relationship between them and malakoplakia cannot be clarified by existing scientific studies. The pathological diagnosis was malakoplakia with aberrant ALK expression by immunohistochemistry. The antibiotics imipenem and vancomycin were started based on the results of drug sensitivity analysis and the patient was subsequently discharged. She experienced no discomfort during 30 months of follow-up.ConclusionThis is the first reported case of malakoplakia with aberrant ALK expression, it should be differentiated from ALK-positive histiocytosis to avoid misdiagnosis.

Novel Starter Strain Enterococcus faecium DMEA09 from Traditional Korean Fermented Meju.

The Enterococcus faecium strain DMEA09 was previously isolated from traditional Korean fermented meju. The objective of the current study was to investigate the traits of E. faecium strain DMEA09 as a starter candidate, focusing on its safety and technological properties. Regarding its safety, the DMEA09 strain was found to be sensitive to nine antibiotics (ampicillin, chloramphenicol, erythromycin, gentamicin, kanamycin, streptomycin, tetracycline, tylosin, and vancomycin) by showing lower minimum inhibitory concentrations (MICs) than the cut-off values suggested by the European Union Food Safety Authority for these nine antibiotics. However, its MIC value for clindamycin was twice as high as the cut-off value. A genomic analysis revealed that strain DMEA09 did not encode the acquired antibiotic resistance genes, including those for clindamycin. The DMEA09 strain did not show hemolysis as a result of analyzing α- and β-hemolysis. It did not form biofilm either. A genomic analysis revealed that strain DMEA09 did not encode for any virulence factors including hemolysin. Most importantly, multilocus sequence typing revealed that the clonal group of strain DMEA09 was distinguished from clinical isolates. Regarding its technological properties, strain DMEA09 could grow in the presence of 6% salt. It showed protease activity when the salt concentration was 3%. It did not exhibit lipase activity. Its genome possessed 37 putative protease genes and salt-tolerance genes for survivability under salt conditions. Consequently, strain DMEA09 shows safe and technological properties as a new starter candidate. This was confirmed by genome analysis.

Phytochemical screening and antimicrobial activity of plant leaf extract against enteric bacterial pathogens

Punica granatum, a fruit-bearing shrub belonging to the Lythraceae family, offers various benefits to humans, with both its fibers and seeds being valuable. The seeds contain important oil acids such as palmitic, punica, stearic, and oleic acids. In India, P. granatum (pomegranate) leaves have been investigated for their potential antibacterial activity against enteric pathogens. These pathogens are responsible for causing gastrointestinal infections and are often associated with antibiotic resistance. The study aims to explore whether pomegranate leaves possess properties that can combat these enteric pathogens effectively. This research holds promise in identifying a natural and alternative approach to address antibacterial challenges, potentially contributing to the development of novel antimicrobial agents pomegranate is commonly used as a traditional remedy for treating enteric bacterial pathogens. To investigate its antibacterial properties, researchers studied the aqueous extract of P. granatum leaf against enteric pathogens, conducting tests like biochemical examinations and microscopy on the isolates. The phytochemical analysis of P. granatum (pomegranate) leaf aqueous extract revealed the presence of various bioactive compounds. These compounds include amino acids, carbohydrates, alkaloids, steroids, flavonoids, terpenoids, saponins, tannins, and phenols. To evaluate its antimicrobial activity, the researchers used antibiotic discs, including chloramphenicol, vancomycin, and gentamicin, employing the standard Kirby Bauer method. Results showed that vancomycin had the highest zone of inhibition, followed by chloramphenicol and gentamicin, with respective measurements of 20 mm and 19 mm. Chloramphenicol exhibited sensitivity against Escherichia coli (19 mm), while gentamicin showed sensitivity against Salmonella typhi (20 mm), Staphylococcus aureus (19 mm), and E. coli (18 mm). Vancomycin demonstrated sensitivity against S. aureus (21 mm). The aqueous leaf extract displayed significant antibacterial activity at concentrations of 20, 40 mcg, and 60 μg, showing effective zones of inhibition ranging from 15 mm to 22 mm against Pseudomonas aeruginosa, E. coli, S. aureus, Shigella dysentriae, Proteus vulgaris, and S. typhi. In conclusion, the study established that P. granatum leaf extracts possess remarkable antibacterial properties and contain valuable pharmaceutical bioactive compounds. Due to its efficacy in treating gastrointestinal disorders, it is utilized as a natural remedy in traditional medicine.

Assessment of the Antivirulence Potential of Tamarix aphylla Ethanolic Extract against Multidrug-Resistant Streptococcus mutans Isolated from Iraqi Patients.

Halophytes have long been used for medicinal purposes. However, their use was entirely empirical, with no knowledge of the bioactive compounds. The plant Tamarix aphylla L. has not drawn the deserving attention for its phytochemical and bioactive explorations, but available data expressed its needs to be attended for its potential. The Streptococcus mutans SpaP gene (cell-surface antigen) mediates the binding of these bacteria to tooth surfaces. The growing problem of antibiotic resistance triggered the research on alternative antimicrobial approaches. Our study aims to explore the activity of T. aphylla ethanolic extract against the virulence gene found in Streptococcus mutans pathogenic bacteria. Samples that were previously collected and identified in our previous work (in press) were obtained from different dental clinics and hospitals in Baghdad. Three nonbiofilm-forming bacterial isolates having multidrug resistance (MDR) for 10 antibiotics (doxycycline, ofloxacin, tetracycline, erythromycin, vancomycin, clindamycin, rifampicin, imipenem, amikacin, and cefepime) were selected to examine the potential of the T. aphylla ethanolic extract. The ethanolic extract showed high antimicrobial activity against MDR. Minimum inhibition concentration (MIC) for the extract was 17.5 mg/ml, while minimum bactericidal concentration (MBC) was 35 mg/ml. The phytochemical compounds present in the ethanolic extract were determined by using high-performance liquid chromatography (HPLC) which revealed that the leaves contain thirteen different alkaloids, twelve flavonoids, and four vitamins. The extract strongly inhibited a virulence property, the adherence of S. mutans which reduced during critical growth phases. The one-step RT-PCR method was used to study the SpaP gene expression of bacterial isolates which significantly reduced. In conclusion, extraction of T. aphylla leaves showed an antimicrobial effect against MDR S. mutans. The identified phytochemicals in the T. aphylla extract are reported to be biologically important and need further investigation to develop safe and cheap drugs.

Increased incidence of teicoplanin-non-susceptible Staphylococcus epidermidis strains: a 6-year retrospective study

Glycopeptide antibiotics (vancomycin and teicoplanin) are usually used for the treatment of Staphylococcus epidermidis infections owing to their increased oxacillin resistance. However, S. epidermidis strains with decreased susceptibility to teicoplanin have become increasingly incident in recent years. We aimed to identify the characteristics of teicoplanin-non-susceptible (Teico-NS) S. epidermidis isolated at our hospital and analyze its relationship with teicoplanin usage. We retrospectively evaluated 328 S. epidermidis strains isolated from clinical isolates between January 2016 and December 2021. All strains were susceptible to vancomycin (minimal inhibitory concentration (MIC) ≤ 4 mg/L). The annual incidence for S. epidermidis strains with an elevated teicoplanin MIC of 8 mg/L ranged from 22.2 to 28.9%. In addition, in 2021, the number of S. epidermidis strains with teicoplanin MIC ≥ 16 mg/L rapidly increased (n = 13, 32.5%). Furthermore, teicoplanin use increased annually until 2019; however, in 2020, it decreased abruptly due to the COVID 19 pandemic. Thus, we could not confirm the existence of a clear correlation between teicoplanin usage and increased incidence of S. epidermidis with reduced teicoplanin-susceptibility. We showed the increased incidence of Teico-NS S. epidermidis in recent years. Further studies are needed to identify the mechanisms and risk factors for teicoplanin-resistance in S. epidermidis.

Isolation and characterization of bioprotective lactic acid bacteria from Moroccan fish and seafood.

The microbiota of aquatic animals is heavily influenced by their environment, offering a potential source for biotechnologically relevant microorganisms. In this investigation, bacterial strains from fish and fish products were investigated to determine their antimicrobial effects against fish and food pathogens. Twelve strains, including five Lactococcus, two Enterococcus hirae, two Enterococcus mundtii, and three Latilactobacillus sakei were selected as producing bacteriocin-like substances with antimicrobial properties that were active against a broad spectrum of bacteria, such as Listeria monocytogenes, Staphylococcus aureus, and Pseudomonas aeruginosa. Selected strains were identified via 16S rRNA sequencing. Most strains exhibited sensitivity to eight types of antibiotics (erythromycin, tetracycline, chloramphenicol, vancomycin, fosfomycin, gentamicin, ampicillin, and netilmicin), lacked hemolysin and gelatinase virulence factors, and did not produce histamine. These findings suggest that marine fish may be a promising source of lactic acid bacteria strains with antimicrobial potential for use as biopreservatives in the food industry.

Antibacterial potential and modes of action of methanol extracts of flowers and leaves of Vernonia glabra (Steetz) Vatke (Asteraceae) against multidrug-resistant Gram-negative bacteria overexpressing efflux pumps

Background: Bacterial infections caused by multidrug-resistant (MDR) Gram-negative bacteria remain a public health problem and have contributed to a reduction in the range of antibiotics available for antibiotic therapy. The search for new antibacterial substances is becoming increasingly important, and plants represent an important reservoir of therapeutic molecules. In the present study, the antibacterial activity and modes of action of Vernonia glabra against Gram-negative and multi-resistant bacteria were evaluated. Methods: The antibacterial activity of Vernonia glabra extracts was assessed using the broth microdilution method, and the effects of the flower extract on bacterial growth kinetics and on the H+-proton pump/ATPase of Providencia stuartii ATCC29916 were carried out using standard experimental protocols; qualitative reference methods were used to identify the secondary metabolites present in the extracts. Results: Phytochemical screening of Vernonia glabra flower and leaf extracts revealed the presence of alkaloids, phenols, flavonoids, tannins, triterpenes, saponins and anthocyanins. The flower and leaf extracts showed antibacterial activity of 100% and 93.33% respectively against the bacteria tested. With minimum inhibitory concentrations (MICs) ranging from 32 µg/mL to 2048 µg/mL, the flower extract showed excellent activity against Escherichia coli AG100 and Providencia stuartii ATCC29916 with a MIC of 32 µg/mL, while the leaf extract showed good activity against Klebsiella pneumoniae ATCC11296 and Providencia stuartii PS2636 with a MIC of 256 µg/mL. The flower extract inhibited the growth of Providencia stuartii ATCC22916 at the exponential phase and inhibited its H+ proton pumps/ATPase. In the presence of the efflux pump inhibitor, phenylalanine-arginine β-naphthylamide (PAβN), the activity of the leaf extract was enhanced on 90.90% of the bacteria tested. With activity enhancement factors ranging from 2 to 128, both extracts potentiated the activity of antibiotics (imipenem, ampicillin, levofloxacin, tetracycline, vancomycin, ceftriaxone, ciprofloxacin, and doxycycline) against at least 70% of the bacteria tested. Conclusion: The results obtained in the present work show that Vernonia glabra is a source of antibacterial molecules that can be used against MDR Gram-negative bacteria. Keywords: Antibacterial; Asteraceae; efflux pumps; modes of action; multidrug resistance; Vernonia glabra.

Distribution of Bacterial Species and Resistance Patterns in Surgical Site Infection after Prior Administration of Vancomycin and Tobramycin Intrawound Powdered Antibiotic Prophylaxis.

Evaluate the species distribution and resistance patterns of bacterial pathogens causing surgical site infection (SSI) after operative fracture repair, with and without the use of intrawound powdered antibiotic (IPA) prophylaxis during the index surgery. Retrospective cohort study. Academic, level 1 trauma center, 2018-2020. Fifty-nine deep SSIs were identified in a sample of 734 patients with 846 fractures (IPA [n = 320], control [n = 526]; open [n = 157], closed fractures [n = 689]) who underwent orthopaedic fracture care. Among SSIs, 28 (48%) patients received IPA prophylaxis and 25 (42%) of the fractures were open. Intrawound powdered vancomycin and tobramycin. Distribution of bacterial species and resistance patterns causing deep surgical site infections requiring operative debridement. Zero patients developed infections caused by resistant strains of streptococci, enterococci, gram-negative enterics, Pseudomonas , or Cutibacterium species. The only resistant strains isolated were methicillin resistance (19%) and oxacillin-resistant coagulase-negative staphylococci (16%). There was no associated statistical difference in the proportion of bacterial species isolated, their resistance profiles, or rate of polymicrobial infections between the IPA and control group. Most (93%) cases using IPAs included vancomycin and tobramycin powders. There were 59 SSIs; 28 (9%) in the IPA cohort and 31 (6%) in the control cohort ( P = 0.13). The use of local antibiotic prophylaxis resulted in no measurable increase in the proportion of infections caused by resistant bacterial pathogens after operative treatment of fractures. However, the small sample size and limited time frame of these preliminary data require continued investigation into their role as an adjunct to SSI prophylaxis. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACTERIOLOGICAL PROFILE OF WOUND INFECTION AND ANTIBIOTIC SUSCEPTIBILITY PATTERNS IN A PUBLIC HOSPITAL IN SURABAYA, INDONESIA

Background: Pyogenic infections that occur can be caused by direct bacterial contamination of the wound, such as infection in a post-surgical wound or infection after trauma. Efforts to control infection can be done with the use of antibiotics. Purpose: To determine the profile of bacteria and antibiotic sensitivity in wound culture in hospitalized patients in Hajj General Hospital Surabaya, East Java in 2021. Method: This study used the Chi-square test and descriptive analysis in the form of distribution tables and percentages using secondary data based on the results of examination of pus culture at the Clinical Microbiology Laboratory in Hajj General Hospital Surabaya, East Java in 2021. Result: The results of research on wound culture samples showed as many as 113 patients (56.22%) with positive culture results, which were predominantly female as many as 59 patients (50.9%) and the highest age category namely at the age of 46-55 years as many as 39 patients (33.6%). Based on bacteria, the most dominant type of bacteria in the Gram-negative group was Escherichia coli ESBL with 21 isolates (26.6%), while Gram-positive bacteria, Staphylococcus aureus, was found in 16 isolates (43.3). The results of antibiotic sensitivity on Gram-negative bacteria were Piperacillin/Tazobactam and Meropenem, and on Gram-positive bacteria Vancomycin and Linezolid were obtained. Conclusion: E. coli and S. aureus are the most important causes of wound infections and the suppressor organisms in this study. Antibiotic susceptibility testing of all isolates showed that the antibiotics amikacin and meropenem were sensitive to Gram-negative bacteria especially ESBL-producing bacteria, and the antibiotics vancomycin and linezolid were sensitive to Gram-positive bacteria especially MRSA.