Virulence factors and antibiotic resistance properties of the Staphylococcus epidermidis strains isolated from hospital infections in Ahvaz, Iran

Ethnomedicine, antibacterial activity, antioxidant potential and phytochemical screening of selected medicinal plants in Dibatie district, Metekel zone, western Ethiopia

BACKGROUND

Medicinal plants play a major role in the delivery of healthcare, particularly among the rural population of Ethiopia. Plant extracts and their bioactive compounds have been utilized for the treatment of several diseases. This study was aimed at evaluating the antibacterial activity, antioxidant capacity, and phytochemical content of selected medicinal plants used in Dibatie district, western Ethiopia.

METHODS

Study plants were collected, shade dried, pulverized, extracted by maceration in 80% ethanol, and subjected to antibacterial, antioxidant, and phytochemical tests. Minimum inhibitory concentration (MIC) was determined using 96-well microplates and nutrient broth microdilution. Antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Phytochemical screening was conducted using standard test methods.

RESULTS

The ethanolic extract of Polystachya steudneri Rchb.f. pseudobulbs was the most active against gram-negative Proteus mirabilis, Salmonella typhimurium, Klebsiella pneumoniae, Escherichia coli, and Shigella flexneri, with MIC values of 8 ± 0, 11 ± 5, 3 ± 1, 3 ± 1, and 2 ± 0 mg/mL, respectively. The ethanolic extract of P. steudneri was also the most effective against gram-positive Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, and Enterococcus faecalis, with MIC values of 8 ± 0, 8 ± 0, 3 ± 1, and 16 ± 0 mg/mL, respectively. Ethanolic extracts of Gnidia involucrata Steud. ex A.Rich. stems and roots were effective antioxidants, with respective 50% DPPH free radical inhibitory concentrations (IC50) of 168.68 and 181.79 µg/mL, followed by that of P. steudneri (IC50 = 203.11 µg/mL). The study plants contained alkaloids, anthocyanins, anthraquinones, cardiac glycosides, coumarins, flavonoids, phenols, saponins, steroids, tannins, and terpenoids.

CONCLUSIONS

This study confirmed the antibiotic, antioxidant, and phytochemical constituents of the investigated plants and suggested further investigations that may lead to bioactive lead compounds.

Deletion of codY impairs Staphylococcus epidermidis biofilm formation, generation of viable but non-culturable cells and stimulates cytokine production in human macrophages

Introduction. Staphylococcus epidermidis biofilms are one of the major causes of bloodstream infections related to the use of medical devices. The diagnosis of these infections is challenging, delaying their treatment and resulting in increased morbidity and mortality rates. As such, it is urgent to characterize the mechanisms employed by this bacterium to endure antibiotic treatments and the response of the host immune system, to develop more effective therapeutic strategies. In several bacterial species, the gene codY was shown to encode a protein that regulates the expression of genes involved in biofilm formation and immune evasion. Additionally, in a previous study, our group generated evidence indicating that codY is involved in the emergence of viable but non-culturable (VBNC) cells in S. epidermidis.Gap statement/Hypothesis. As such, we hypothesized that the gene codY has have an important role in this bacterium virulence.Aim. This study aimed to assess, for the first time, the impact of the deletion of the gene codY in S. epidermidis virulence, namely, in antibiotic susceptibility, biofilm formation, VBNC state emergence and in vitro host immune system response.Methodology. Using an allelic replacement strategy, we constructed and then characterized an S. epidermidis strain lacking codY, in regards to biofilm and VBNC cell formation, susceptibility to antibiotics as well as their role in the interaction with human blood and plasma. Additionally, we investigate whether the codY gene can impact the activation of innate immune cells by evaluating the production of both pro- and anti-inflammatory cytokines by THP-1 macrophages.Results. We demonstrated that the deletion of the gene codY resulted in biofilms with less c.f.u. counts and fewer VBNC cells. Furthermore, we show that although WT and mutant cells were similarly internalized in vitro by human macrophages, a stronger cytokine response was elicited by the mutant in a toll-like receptor 4-dependent manner.Conclusion. Our results indicate that codY contributes to S. epidermidis virulence, which in turn may have an impact on our ability to manage the biofilm-associated infections caused by this bacterium.

Evaluation of visible light and natural photosensitizers against Staphylococcus epidermidis and Staphylococcus saprophyticus planktonic cells and biofilm

Antimicrobial photoinactivation (API) has shown some promise in potentially treating different nosocomial bacterial infections, however, its application on staphylococci, especially other than Staphylococcus aureus or methicillin-resistant S. aureus (MRSA) species is still limited. Although S. aureus is a well-known and important nosocomial pathogen, several other species of the genus, particularly coagulase-negative Staphylococcus (CNS) species such as Staphylococcus epidermidis and Staphylococcus saprophyticus, can also cause healthcare-associated infections and foodborne intoxications. CNS are often involved in resilient biofilm formation on medical devices and can cause infections in patients with compromised immune systems or those undergoing invasive procedures. In this study, the effects of chlorophyllin and riboflavin-mediated API on S. epidermidis and S. saprophyticus planktonic cells and biofilm are demonstrated for the first time. Based on the residual growth determination and metabolic reduction ability changes, higher inactivating efficiency of chlorophyllin-mediated API was determined against the planktonic cells of both tested species of bacteria and against S. saprophyticus biofilm. Some insights on whether aqueous solutions of riboflavin and chlorophyllin, when illuminated with optimal exciting wavelength (440 nm and 402 nm, respectively) generate O2-•, are also provided in this work.

Comparison of prophylactic antibiotics for endonasal transsphenoidal surgery using a national inpatient database in Japan

BACKGROUND

The choice of prophylactic antibiotics for use in endonasal transsphenoidal surgery (ETSS) lacks universal standards. This study aimed to investigate the effectiveness of cefazolin, ampicillin and third-generation cephalosporins for preventing postoperative meningitis and secondary outcomes (in-hospital death and the combination of pneumonia and urinary tract infection) in patients who have undergone ETSS.

METHODS

The study used data from the Diagnosis Procedure Combination database in Japan. Data from 10 688 patients who underwent ETSS between April 2016 and March 2021 were included. Matching weight analysis based on propensity scores was conducted to compare the outcomes of patients receiving cefazolin, ampicillin or third-generation cephalosporins as prophylactic antibiotics.

RESULTS

Of the 10 688 patients, 9013, 102 and 1573 received cefazolin, ampicillin and third-generation cephalosporins, respectively. The incidence of postoperative meningitis did not significantly differ between the cefazolin group and the ampicillin group (OR, 1.02; 95% CI, 0.14-7.43) or third-generation cephalosporins group (OR, 0.81; 95% CI, 0.10-6.44). Similarly, in-hospital death and the composite incidence of pneumonia and urinary tract infection did not differ between the cefazolin group and the ampicillin or third-generation cephalosporins group.

CONCLUSIONS

Cefazolin, ampicillin and third-generation cephalosporins as perioperative prophylactic antibiotics for ETSS do not differ significantly in terms of preventing meningitis.

Decreased susceptibility to vancomycin and other mechanisms of resistance to antibiotics in Staphylococcus epidermidis as a therapeutic problem in hospital treatment

Multidrug-resistant coagulase-negative staphylococci represent a real therapeutic challenge. The aim of the study was to emphasize the importance of heteroresistance to vancomycin presence in methicillin-resistant strains of S. epidermidis. The research comprised 65 strains of S. epidermidis. Heteroresistance to vancomycin was detected with the use of the agar screening method with Brain Heart Infusion and a population profile analysis (PAP test). In addition, types of cassettes and genes responsible for resistance to antibiotics for 22 multidrug resistant strains were determined. Our investigations showed that 56 of 65 S. epidermidis strains were phenotypically resistant to methicillin. The tested strains were mostly resistant to erythromycin, gentamicin, clindamycin, and ciprofloxacin. Six strains showed decreased susceptibility to vancomycin and their heterogeneous resistance profiles were confirmed with the PAP test. All tested multi-resistant strains exhibited the mecA gene. More than half of them possessed type IV cassettes. ant(4')-Ia and aac(6')/aph(2''), ermC and tetK genes were most commonly found. The described phenomenon of heteroresistance to vancomycin in multidrug resistant bacteria of the Staphylococcus genus effectively inhibits a therapeutic effect of treatment with this antibiotic. That is why it is so important to search for markers that will enable to identify heteroresistance to vancomycin strains under laboratory conditions.

Medical Astro-Microbiology: Current Role and Future Challenges

The second and third decades of the twenty-first century are marked by a flourishing of space technology which may soon realise human aspirations of a permanent multiplanetary presence. The prevention, control and management of infection with microbial pathogens is likely to play a key role in how successful human space aspirations will become. This review considers the emerging field of medical astro-microbiology. It examines the current evidence regarding the risk of infection during spaceflight via host susceptibility, alterations to the host's microbiome as well as exposure to other crew members and spacecraft's microbiomes. It also considers the relevance of the hygiene hypothesis in this regard. It then reviews the current evidence related to infection risk associated with microbial adaptability in spaceflight conditions. There is a particular focus on the International Space Station (ISS), as one of the only two  crewed objects in low Earth orbit. It discusses the effects of spaceflight related stressors on viruses and the infection risks associated with latent viral reactivation and increased viral shedding during spaceflight. It then examines the effects of the same stressors on bacteria, particularly in relation to changes in virulence and drug resistance. It also considers our current understanding of fungal adaptability in spaceflight. The global public health and environmental risks associated with a possible re-introduction to Earth of invasive species are also briefly discussed. Finally, this review examines the largely unknown microbiology and infection implications of celestial body habitation with an emphasis placed on Mars. Overall, this review summarises much of our current understanding of medical astro-microbiology and identifies significant knowledge gaps.

Graphical Abstract

Antibacterial activity and synergic effects of the essential oils of Amomum verum Blackw and Zanthoxylum limonella (Dennst.) Alston

The antibacterial activity of Amomum verum Blackw, Zanthoxylum limonella (Dennst.) Alston, Zanthoxylum bungeanum, and Zingiber montanum (J. Koenig) Link ex A. Dietr essential oils were investigated against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa. The essential oils of A. verum Blackw, Z. limonella (Dennst.) Alston, Z. bungeanum, and Z. montanum (J. Koenig) Link ex A. Dietr displayed strong antibacterial activity with a minimum inhibitory concentration and minimumbactericidal concentration ranging from 0.31 to 1.25 µg/mL and 0.62-5.00 µg/mL, respectively. The chemical composition of A. verum Blackw, Z. limonella (Dennst.) Alston, Z. bungeanum, and Z. montanum (J. Koenig) Link ex A. Dietr essential oils were analysed using gas chromatography-mass spectrometry. 1,8-Cineole and limonene were detected in high amounts in the A. verum Blackw and Z. limonella (Dennst.) Alston essential oils, respectively. The major compound in Z. bungeanum and Z. montanum (J. Koenig) Link ex A. Dietr essential oil was 2,4-dimethylether-phloroacetophenone and terpinene-4-ol, respectively. The antibacterial activities and synergistic effects between these essential oils were further analysed. The combination of A. verum Blackw and Z. limonella (Dennst.) Alston essential oils showed a synergistic effect against all bacterial strains, while the other essential oil combinations showed additive, antagonistic effects, and no interaction. The synergistic effect of the combination between A. verum Blackw and Z. limonella (Dennst.) Alston essential oils could be resulted from 1,8-cineole and limonene which was evaluated to possess strong antibacterial activity.

Antimicrobial Effects of Tetraspanin CD9 Peptide against Microbiota Causing Armpit Malodour

Synthetic peptides, including tetraspanin CD9 peptides, are increasingly coming into focus as new treatment strategies against various organisms, including bacteria, that cause underarm odour. The use of deodorants and antiperspirants is associated with side effects. Therefore, it is critical to find an alternative therapeutic approach to combat underarm odour. The aim of this study is to investigate the antibacterial effect of tetraspanin CD9 peptides against the skin microbiota that cause malodour in the underarms. The antimicrobial activity of CD9 peptides against Micrococcus luteus (M. luteus), Bacillus subtilis (B. subtilis), Staphylococcus epidermidis (S. epidermidis), and Corynebacterium xerosis (C. xerosis) was investigated by the disc diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution assays using CD9 peptide concentrations ranging from 1 mg/mL to 0.0078 mg/mL. In addition, the anti-biofilm activity of the CD9 peptides was determined. The CD9 peptides showed different antibacterial activity with an inhibition zone of 7.67, 9.67, 7.00, and 6.00 mm for S. epidermidis, M. luteus, C. xerosis, and B. subtilis, respectively. All bacteria had the same MBC value of 1 mg/mL. A high MIC of CD9 peptides was observed for S. epidermidis and M. luteus at 0.5 mg/mL. The MIC values of B. subtilis and C. xerosis were 0.125 mg/mL and 0.25 mg/mL, respectively. CD9 peptides significantly inhibited biofilm development of S. epidermidis, B. subtilis, and C. xerosis isolates. The CD9 tetraspanin peptide has excellent antibacterial activity against bacteria that cause underarm odour. Therefore, the CD9 tetraspanin peptide is a promising alternative to deodorants and antiperspirants to combat commensal bacteria of the skin that cause underarm odour.

Synergistic Potentiation of Antimicrobial and Antibiofilm Activities of Penicillin and Bacitracin by Octyl Gallate, a Food-Grade Antioxidant, in Staphylococcus epidermidis

Staphylococcus epidermidis is a major nosocomial pathogen that frequently forms biofilms on indwelling medical devices. This study aimed to investigate the synergistic antimicrobial and antibiofilm activities of octyl gallate (OG) in combination with penicillin and bacitracin against S. epidermidis. Antimicrobial synergy was assessed by conducting checkerboard titration assays, and antibiofilm activity was determined with biofilm assays and fluorescence microscopy analysis. The presence of 8 µg/mL of OG increased both the bacteriostatic and bactericidal activities of penicillin and bacitracin against S. epidermidis. It lowered the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of penicillin by eight-fold and those of bacitracin by four-fold. Moreover, when used with penicillin or bacitracin, OG significantly decreased the level of biofilm production by preventing microcolony formation. Furthermore, OG significantly permeabilized the bacterial cell wall, which may explain its antimicrobial synergy with penicillin and bacitracin. Together, these results demonstrate that OG, a food-grade antioxidant, can be potentially used as a drug potentiator to enhance the antimicrobial and antibiofilm activities of penicillin and bacitracin against S. epidermidis.

Intracellular bacterial communities in patient with recurrent urinary tract infection caused by Staphylococcus spp and Streptococcus agalactiae: a case report and literature review

Background

 Urinary tract infections (UTI) are among the most frequent pathologies worldwide. Uropathogenic Escherichia coli (UPEC) is the leading etiological agent; however, depending on the patient's characteristics, the etiology may include some atypical pathogens. Some pathogenic bacteria can internalize in the urothelial and phagocytic cells complicating treatment and timely diagnosis.

Case presentation

We present a clinical case of a married female patient with urological alteration, constant catheterization, and urethral dilation with recurrent UTI for ten years, with five episodes per year and reports of negative urine culture. The microscopic analysis revealed intracellular bacterial communities (IBC) and pyocytes with active bacteria. A protocol was designed for the release of intracellular bacteria in urine samples; without the proposed treatment, the urine culture was negative. However, upon releasing the internalized bacteria, we obtained a polymicrobial urine culture. We isolated and identified Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus simulans, and Streptococcus agalactiae. All microorganisms were sensitive to nitrofurans and sulfas. The patient is under treatment with nitrofurantoin and continuous follow-up by our workgroup.

Conclusions

 It is essential to look for IBC and pyocytes with active bacteria in patients with recurrent UTIs to avoid false-negative urine culture results and provide timely treatment. Polymicrobial culture must be considered depending on the patient and clinical history.

Characterization of Staphylococcus epidermidis clinical isolates from hospitalized patients with bloodstream infection obtained in two time periods

Background

In recent years Staphylococcus epidermidis has been considered an important and frequent causative agent of health care-associated infections (HAIs), increasing the costs of hospitalization, morbidity, and mortality. Antibiotic resistance and biofilm formation are the most important obstacles in the treatment of infections caused by this microorganism. The aim of this work was to determine the most prevalent STs, as well as the antibiotic resistance profile and biofilm formation of S. epidermidis clinical isolates obtained from hospitalized patients in two hospitals in Acapulco, Guerrero in two time periods.

Methods

Twenty methicillin-resistant S. epidermidis strains isolated from patients with bacteremia in two hospitals in two time periods were analyzed. Identification and antibiotic susceptibility were performed using the Vitek automated system. Molecular confirmation of the identification and methicillin resistance was performed by duplex PCR of the mecA and nuc genes. Biofilm production was analyzed, and the clonal origin was determined by multilocus sequence typing (MLST).

Results

We identified 14 antibiotic resistance profiles as well as 13 sequence types (ST), including the new ST761. We also found that ST2 and ST23 were the most prevalent and, together with ST59, were found in both time periods. Seventeen of our clinical isolates were multidrug-resistant, but all of them were sensitive to linezolid and vancomycin, and this was not related to biofilm production. Additionally, we standardized a duplex PCR to identify methicillin-resistant S. epidermidis strains. In conclusion, S. epidermidis STs 2, 23, and 59 were found in both time periods. This study is the first report of S. epidermidis ST761. The clinical isolates obtained in this work showed a high multidrug resistance that is apparently not related to biofilm production.

Chemistry and Bioactivity of Microsorum scolopendria (Polypodiaceae): Antioxidant Effects on an Epithelial Damage Model

Microsorum scolopendia (MS), which grows on the Chilean island of Rapa Nui, is a medicinal fern used to treat several diseases. Despite being widely used, this fern has not been deeply investigated. The aim of this study was to perform a characterization of the polyphenolic and flavonoid identity, radical scavenging, antimicrobial, and anti-inflammatory properties of MS rhizome and leaf extracts (RAE and HAE). The compound identity was analyzed through the reversed-phase high-performance liquid chromatography (RP-HPLC) method coupled with mass spectrometry. The radical scavenging and anti-inflammatory activities were evaluated for DPPH, ORAC, ROS formation, and COX inhibition activity assay. The antimicrobial properties were evaluated using an infection model on Human Dermal Fibroblast adult (HDFa) cell lines incubated with Staphylococcus aureus and Staphylococcus epidermidis. The most abundant compounds were phenolic acids between 46% to 57% in rhizome and leaf extracts, respectively; followed by flavonoids such as protocatechic acid 4-O-glucoside, cirsimaritin, and isoxanthohumol, among others. MS extract inhibited and disaggregated the biofilm bacterial formed and showed an anti-inflammatory selective property against COX-2 enzyme. RAE generated a 64% reduction of ROS formation in the presence of S. aureus and 87.35% less ROS in the presence of S. epidermidis on HDFa cells. MS has great therapeutic potential and possesses several biological properties that should be evaluated.

Highly Synergistic Effects of Melittin With Vancomycin and Rifampin Against Vancomycin and Rifampin Resistant Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) strains are increasingly emerging as serious pathogens because they can be resistant to many antibiotics called multidrug resistance (MDR) that limit the therapeutic options. In the case of vancomycin- and rifampin-resistant MDR-MRSE, the physicians are not allowed to increase the doses of antibiotics because of severe toxicity. Accordingly, we investigated the synergistic activity of melittin antimicrobial peptide with vancomycin and rifampin against vancomycin-resistant, and rifampin-resistant MDR-MRSE isolates. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), fractional inhibitory concentration index (FICi), and fractional bactericidal concentration index (FBCi) of antimicrobial agents against isolates were determined. Coagulate activities and serum and salt stability as well as melittin cytotoxicity on the human embryonic kidney (HEK) 293 cells and human red blood cells (RBCs) at their synergistic concentrations. MIC and MBC values for melittin were in the range of 0.312–2.5 and 0.312–5, respectively. Results also showed that the interaction of melittin with drugs was highly synergistic in which the geometric means of FICi and FBCi were < 0.5. Induced synergism led to a decrease in melittin, rifampin, and vancomycin concentrations by 8–1,020, 2–16, and 4–16-folds, respectively. This phenomenon caused a reduction in melittin toxicity by which the synergistic concentration of melittin needed to kill bacteria did not show cytotoxicity and hemolytic activity. Besides, no coagulation activity was found for the synergistic and alone concentrations of melittin in both Prothrombin Time (PT) and Partial Thromboplastin Time (PTT). Interestingly, the antibacterial activity of melittin in Mueller Hinton Broth (MHB) containing human serum did no significant differences between MIC and MBC values of melittin in MHB and MHB containing 10% human serum. The present findings showed that the therapeutic index of melittin was improved by 32.08- and 12.82-folds when combined with vancomycin and rifampin, respectively. Taken together, the obtained data show that melittin alone was effective against MDR-MRSE isolates and this antimicrobial peptide showed highly synergistic effects with vancomycin and rifampin without causing toxicity. Therefore, the combination of melittin and traditional antibiotics could be a promising strategy for the treatment of infections caused by MDR-MRSE.

Increased Prevalence of Minocycline-Resistant Staphylococcus epidermidis with tet(M) by Tetracycline Use for Acne Treatment

Staphylococcus epidermidis, a major skin bacterium, can cause opportunistic infections. Use of antimicrobial agents against Cutibacterium acnes for acne treatment becomes a risk factor for emergence of antimicrobial-resistant skin bacteria. In this study, the impact of antimicrobial treatment of acne vulgaris on S. epidermidis antimicrobial resistance was assessed. A total of 344 S. epidermidis strains isolated from patients with acne vulgaris who visited hospital (165 strains) and dermatological clinics (179 strains), respectively, were analyzed. Except for doxycycline, the resistance rates were higher in strains isolated from patients who had used antimicrobials for acne treatment than in those isolated from patients who had not used antimicrobials. The prevalence rates of strains with erm(C) from patients who used macrolides and clindamycin (hospital, 78.0%; clinics, 61.3%) and those of strains with tet(M) from patients who used tetracyclines (hospital, 27.5%; clinics, 42.4%) were significantly higher than those of strains from patients who did not use antimicrobials (p < 0.05). All strains with erm(A) (8/8) and 91.7% strains with erm(C) (156/170) showed high-level resistance to macrolides and clindamycin (MIC ≥256 μg/mL). Furthermore, almost all strains with tet(M) showed resistance to minocycline. Our results showed that the use of antimicrobials for acne treatment may lead to an increased prevalence of antimicrobial-resistant S. epidermidis. In particular, the emergence of minocycline-resistant strains with tet(M) owing to the use of tetracyclines (doxycycline and minocycline) is a critical issue. Appropriate antimicrobial use for acne treatment may be an important strategy to prevent the emergence of antimicrobial-resistant skin bacteria.

Myrica cerifera, a Medicinal Plant of the Lumbee Tribe, has Antibacterial and Nematicidal Properties

Currently threatening the world of medicine is a growing number of antibiotic-resistant diseases. More specifically, bacteria and nematodes have gained resistance to many of the world's leading antibiotics and nematicides, respectively, making infections more difficult to treat. Subsequently, these parasitic organisms are able to continue damaging crops and other living organisms like humans without strong interference. To help people and the environment, the development of new and novel antibiotics is vital. Previous research suggests that phytochemicals are a potential solution that will not only help inhibit bacterial growth but also reduce nematode survival. We hypothesized that Myrica cerifera, a plant often used by the Lumbee tribe to treat illness, possesses antibacterial and nematicidal properties. To answer our hypothesis, we began by collecting plant specimens to extract material for biological assays and to subsequently isolate and elucidate the structures of active components. The extract was evaluated for antibacterial properties with an agar diffusion assay and then nematicidal properties using Caenorhabditis elegans. M. cerifera extract was added onto an agar lawn at various doses, and the nematodes' lifespans were scored. The findings of this study show that extracts of this plant, more commonly referred to as 'wax myrtle', do significantly decrease the lifespan of C. elegans and increase the zone of inhibition for Staphylococcus epidermidis and Staphylococcus aureus. In addition, two compounds were isolated and characterized through chemical extraction, chromatographic separation, and spectroscopic analysis. These compounds could potentially be used to treat bacterial and nematode infections.

Occurrence of bacteria belonging to the genus Enterococcus and Staphylococcus on inanimate surfaces of selected hospital facilities and their nosocomial significance

OBJECTIVES

This work aimed to determine the representation and resistance of bacteria belonging to the genus Staphylococcus and Enterococcus on inanimate surfaces of two selected workplaces of the University Hospital of L. Pasteur in Košice (UHLP) and to investigate their importance in the hospital environment. The men's ward of the Department of Internal Medicine (DIM) and the Department of Anaesthesiology and Intensive Care (DAIC) were chosen.

METHODS

Using sterile sampling kits, a total of 182 swabs were collected from the inanimate surfaces of both UHLP workplaces. The swabs were then transported to a microbiological laboratory and inoculated onto sterile culture media (blood agar containing 5% ram erythrocytes). After culturing (24-48 hours, in a thermostat at constant temperature 37 °C), bacterial colonies were identified by mass spectrometry on a MALDI TOF MS. Bacteria belonging to the genera Staphylococcus and Enterococcus were subsequently separated from the spectrum of identified bacteria. Nosocomial significant strains of staphylococci (Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus aureus) and all isolated enterococci were subjected to susceptibility testing for selected antibiotics using the disk diffusion method - E-tests.

RESULTS

Several members of the genus Staphylococcus were identified from the inanimate surfaces of both workplaces. These were mainly coagulase-negative strains - Staphylococcus epidermidis (45), Staphylococcus capitis (34), Staphylococcus haemolyticus (20), Staphylococcus hominis (45), Staphylococcus pasteuri (2), Staphylococcus sroph (1), Staphylococcus simulans (3), and Staphylococcus warneri (4). Staphylococcus aureus strains were also identified (2). Nosocomial significant isolates were tested for susceptibility to the antibiotics cefoxitin (FOX) and oxacillin (OXA). Two members of the genus Enterococcus - Enterococcus faecium (7) and Enterococcus faecalis (8) were isolated. All strains were subject to vancomycin susceptibility testing using the disk method.

CONCLUSION

Microbial Landscape and Antibiotic Susceptibility Dynamics of Skin and Soft Tissue Infections in Kazakhstan 2018–2020

Skin and soft tissue inflammatory diseases of bacterial origin occupy a significant part of hospitalizations to emergency departments. One of the most common causes of sepsis is soft tissue infection, which accounts for about a quarter of all nosocomial infections. The aim of this study was to determine the differences in microbial landscape and antibiotic susceptibility of soft tissue infection pathogens among adults and children during the period 2018–2020. We studied 110 samples of pus admitted to the Scientific Research laboratory of the Karaganda Medical University from 2018 to 2020. Each sample was studied using the standard and express methods. The antibiotic susceptibility was determined by using the diffuse disk method in accordance with the CLSI 2018 recommendations. As such, 50% of S. epidermidis strains in children and 30% in adults were methicillin resistant. Differences in the resistance of S. aureus strains in children and adults were insignificant. Thus, methicillin-resistant S. aureus (MRSA) was not detected in children, but in adults, on the other hand, their percentage was 12.5%. The third cause of infection in adults was E. coli (13.72%), among which 75% were multidrug resistant. A. baumanii was found in 4.9% of adult patients’ samples, of which 60% were multidrug resistant. The effectiveness of the most prescribed antibiotics decreased due to the isolated strain resistance.

Deciphering mechanisms and implications of bacterial translocation in human health and disease

Significant increases in potential microbial translocation, especially along the oral-gut axis, have been identified in many immune-related and inflammatory diseases, such as inflammatory bowel disease, colorectal cancer, rheumatoid arthritis, and liver cirrhosis, for which we currently have no cure or long-term treatment options. Recent advances in computational and experimental omics approaches now enable strain tracking, functional profiling, and strain isolation in unprecedented detail, which has the potential to elucidate the causes and consequences of microbial translocation. In this review, we discuss current evidence for the detection of bacterial translocation, examine different translocation axes with a primary focus on the oral-gut axis, and outline currently known translocation mechanisms and how they adversely affect the host in disease. Finally, we conclude with an overview of state-of-the-art computational and experimental tools for strain tracking and highlight the required next steps to elucidate the role of bacterial translocation in human health.

Biomimetic Synthesis of Silver Nanoparticles Using Ethyl Acetate Extract of Urtica diocia Leaves; Characterizations and Emerging Antimicrobial Activity

The current work reports the biosynthesis of silver nanoparticles (AgNPs) using the antimicrobial activities of ethyl acetate extract of Urtica diocia (UD) leaves as a reducing and capping agent. The synthesized UD-AgNPs were characterized using UV−visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and dynamic light scattering (DLS). The UD-AgNPs were evaluated against Gram-positive and Gram-negative bacteria, and their size, shape, and distribution were recorded. The average size of an NP was 19.401 nm. The zone of inhibition (ZOI) for 75 µL of UD-AgNPs against Pseudomonas aeruginosa (P. aeruginosa) was 21 ± 0.4 mm more than that of the control drug Ciprofloxacin (16 ± 10 mm). The minimum inhibitory concentration (MIC) was the lowest against Escherichia coli (E. coli) (36 ± 3 µg/mL) and Staphylococcusepidermidis (S. epidermidis) (38 ± 3 µg/mL). Moreover, the minimum bactericidal concentration (MBC) was the lowest against E.coli (75 ± 00 µg/mL) and Enterococcus faecalis (E. faecalis (83 ± 16 µg/mL). Thus, the UD-AgNPs synthesized using the ethyl acetate extract of UD can be used as a new antimicrobial drug.

Antibacterial pyrazoles: tackling resistant bacteria

Bacterial resistance to antibiotics threatens our progress in healthcare, modern medicine, food production and ultimately life expectancy. Antibiotic resistance is a global concern, which spreads rapidly across borders and continents due to rapid travel of people, animals and goods. Derivatives of metabolically stable pyrazole nucleus are known for their wide range of pharmacological properties, including antibacterial activities. This review highlights recent reports of pyrazole derivatives targeting different bacterial strains focusing on the drug-resistant variants. Pyrazole derivatives target different metabolic pathways of both Gram-positive and Gram-negative bacteria.

Multidrug resistant coagulase-negative Staphylococcus spp. isolated from cases of chronic rhinosinusitis in humans. Study from Poland

For many years, coagulase-negative staphylococci (CoNS) have been considered non-pathogenic bacteria. However, recently, CoNS are becoming more common bacteriological factors isolated from cases of chronic rhinosinusitis in humans. Moreover, most of them represent the multidrug-resistant or/and methicillin-resistant profile, which significantly increases the therapeutic difficulties. The aim of the study was to characterize profile of resistant coagulase-negative staphylococci isolated from cases of chronic rhinosinusitis in patients treated in a Medical Center in Warsaw in 2015-2016. The study material was derived from patients with diagnosed chronic rhinosinusitis treated at the MML Medical Center in Warsaw. The material was obtained intraoperatively from maxillary, frontal, and ethmoid sinuses. In total, 1,044 strains were isolated from the studied material. Coagulase-negative staphylococci were predominant, with the largest share of Staphylococcus epidermidis. Isolated CoNS were mainly resistant to macrolide, lincosamide, and tetracycline. Among the S. epidermidis strains, we also showed 35.6% of MDR and 34.7% of methicillin-resistant strains. The same values for other non-epidermidis species were 31.5% and 18.5%, respectively and the percentage of strains with MAR >0.2 was greater in S. epidermidis (32.6%) than S. non-epidermidis (23.9%). Although the percentage of strains resistant to tigecycline, glycopeptides, rifampicin and oxazolidinones was very small (2.3%, 1.9%, 1.4% and 0.7% respectively), single strains were reported in both groups. The study has shown a high proportion of MDR and methicillin-resistant CoNS strains, which indicates a large share of drug-resistant microorganisms in the process of persistence of chronic rhinosinusitis; therefore, isolation of this group of microorganisms from clinical cases using aseptic techniques should not be neglected.

S. epidermidis Isolates from a Tertiary Care Portuguese Hospital Show Very High Antibiotic Non-Susceptible Rates and Significant Ability to Form Biofilms

Healthcare-associated infections (HAIs) have been increasing during recent decades, leading to long hospital stays and high morbidity and mortality rates. The usage of antibiotics therapy against these infections is enhancing the emergence of more multiple-drug resistant strains, in particular in Staphylococcus epidermidis. Hence, this study focused on the resistance pattern of S. epidermidis isolates from clinical settings and its association with phenotypic and molecular traits. Our results showed that HAIs were more prevalent among infants and older adults, and the most frequent type of HAI was central line-associated bloodstream infection. Half of the patients received antibiotic therapy before laboratory diagnosis. Preceding microbiological diagnosis, the number of patients receiving antibiotic therapy increased by 29.1%. Eighty-six per cent of the clinical isolates presented a multidrug resistance (MDR) profile, and a quarter were strong biofilm producers. Furthermore, polysaccharide intercellular adhesin (PIA)-dependent biofilms presented higher biomass production (p = 0.0041) and a higher rate of antibiotic non-susceptibility than PIA-independent biofilms, emphasizing the role of icaABDC operon in infection severity. Therefore, this study suggests that a thorough understanding of the phenotypic and molecular traits of the bacterial cause of the HAIs may lead to a more suitable selection of antibiotic therapy, improving guidance and outcome assessment.

Staphylococcus aureus and S. epidermidis in biological systems of hospital environment: Antibiotic resistance patterns in regions of Ukraine

Staphylococcus bacteria are ubiquitous and often circulate in the biological systems of the hospital environment. Staphylococci have developed antibiotic resistance mechanisms resulting in a significant medical and economic burden to the healthcare system. The goal of our research was to conduct a comparative analysis of resistance to antibiotics in S. aureus and S. epidermidis isolates found in surgical hospitals in Kharkiv and Poltava regions. In 2013 through 2019, 151,015 and 98,754 tests were made by disc-diffusion method to identify the sensitivity in the S. aureus strains to antibiotics in Kharkiv and Poltava regions respectively. In 2013–2015, 15,589 tests were made in Kharkiv region to identify antibiotics sensitivity in S. epidermidis strains. Comparison of antibiotic resistance of the S. aureus strains in Kharkiv and Poltava regions was performed using the Pearson Chi-square test (χ2) and Fisher’s exact test. The proportion of S. aureus strains resistant to penicillins, cephalosporins, carbapenems, aminoglycosides, and macrolides was higher in Kharkiv region in terms of statistical validity than in Poltava region. Overall, the proportion of S. aureus strains resistant to lincozamids, tetracycline antibiotics, and fluoroquinolones in Poltava region was higher in terms of statistical validity than in Kharkiv region. An analysis of resistance of S. aureus strains to linezolid demonstrated that in Poltava region the proportion of resistant microorganisms was higher in terms of statistical validity in 2013–2014 and in 2016–2018. In Kharkiv region, in 2013 and in 2014, 96.3% and 89.1% of isolated strains of S. aureus respectively, were resistant to vancomycin. In 2019, more than a quarter of the located isolates (26.6%) in Poltava region were resistant to this antibiotic. The analysis of the dynamic of resistance in S. epidermidis isolates demonstrated that in 2015 nearly half of the isolates located in Kharkiv region were insensitive to penicillin antibiotics. Between 2013 and 2015, the spread of resistance to cephalosporins, aminoglycosides, macrolides, and fluoroquinolones among the S. epidermidis isolates noticeably increased. When S. epidermidis resistance to vancomycin was analyzed, a decrease in the proportion of resistant strains from 88.0% in 2013 to 8.7% in 2015 was noted. A promising direction for further research is the creation of passports of microorganism resistance in the regions and various health-care settings, as well as the creation of a unified national database network on microorganism resistance using modern methodologies for determining the phenotypes and genotypes of microorganisms.

Antimicrobial Resistance of Staphylococcus aureus Isolated from Hospital Wastewater in Kermanshah, Iran

Introduction

Hospital wastewater contains highly resistant and virulent bacteria that can spread into the environment. This study was conducted to investigate the antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) in raw and treated hospital wastewater.

Methods

During a three-month period, 40 sewage samples were collected from the hospital sewage (Kermanshah, Iran), and S. aureus were identified using culture and biochemical tests. MRSA was detected by resistance to cefoxitin. Antibiotic resistance (AR) was determined using disk diffusion according to the Clinical and Laboratory Standards Institute (CLSI) in 20 MSSA (10 raw and 10 treated sewage) and 40 MRSA isolates (20 raw and 20 treated sewage). The antimicrobial resistance genes (ARGs) were determined by PCR.

Results

Eleven and eight percent of the isolates were MRSA in raw and treated sewage samples, respectively. Out of 60 isolates, 59 (98%) were multidrug resistant (MDR). The most common ARGs were mecA (raw=100%, treated=100%), aacA-D (raw=100%, treated=85%) and tetK (raw =95%, treated =45%) in MRSA, while the tetM gene was the most abundant gene (raw=50%, treated=80%) in MSSA. None of isolates (n=60) was positive for the vanB gene. MSSR (n=20) had the highest level of resistance against penicillin (100%), clindamycin (raw=90%, treated=90%), azithromycin (raw=80%, treated=90%). All MRSA isolates (n=40,100%) in both raw and treated sewage samples were non-susceptible to penicillin, oxacillin and azithromycin. There was no significant difference in the frequency AR and ARGs between raw and treated sewage samples (p>0.05).

Conclusion

The results indicated a high frequency of MDR and ARGs in both raw and treated sewage isolates which could be released into the environment through sewage system and pose a serious threat to public health. Hospital wastewater treatment processes should be improved in order to prevent the dissemination of the most resistant strains of S. aureus.

Genotypic and phenotypic analysis of biofilm formation Staphylococcus epidermidis isolates from clinical specimens

OBJECTIVES

Staphylococcus epidermidis is the primary causative agent of infections associated with indwelling biomaterials. Antibiotic susceptibility patterns, Biofilm formation capability, and screening of responsible genes in biofilm formation procedure in clinical isolates (icaA, icaB, icaC, icaD, sdrG, and atlE) were assigned as the main objectives in this study. The clinical samples were analyzed via standard biochemical assays for identifying different bacteria which were confirmed using the multiplex colony PCR method. Subsequently, biofilm-formation capability, antibiotic susceptibility testing, and the frequency of genes responsible for biofilm formation in the confirmed strains were checked.

RESULTS

Out of 183 clinical specimens 54 S. epidermidis isolates were detected by targeting a housekeeping gene (sesc) taking advantage of the PCR procedure. All of the strains were Biofilm forming producers. The in vitro biofilm formation assays determined that 45 (83.33%), 5 (9.26%), 4 (7.41%) were strong, moderate, and weak biofilm former strains respectively. Among the isolated strains, the specific frequencies of the biofilm-forming genes were specified to be (98%) for sdrG, (84%) for atlE, (80%) for icaC, and (70%) for icaD. Cefamandole and Amikacin are the most effective antibiotics in isolated strains. All strains were ascertained to be methicillin and amoxicillin/clavulanic acid resistant.

Metabolism, ATP production and biofilm generation by Staphylococcus epidermidis in either respiratory or fermentative conditions

Staphylococcus epidermidis is a Gram-positive saprophytic bacterium found in the microaerobic/anaerobic layers of the skin that becomes a health hazard when it is carried across the skin through punctures or wounds. Pathogenicity is enhanced by the ability of S. epidermidis to associate into biofilms, where it avoids attacks by the host and antibiotics. To test the effect of oxygen on metabolism and biofilm generation, cells were cultured at different oxygen concentrations ([O₂]). As [O₂] decreased, S. epidermidis metabolism went from respiratory to fermentative. Remarkably, the rate of growth decreased at low [O₂] while a high concentration of ATP ([ATP]) was kept. Under hypoxic conditions bacteria associated into biofilms. Aerobic activity sensitized the cell to hydrogen peroxide-mediated damage. In the presence of metabolic inhibitors, biofilm formation decreased. It is suggested that at low [O₂] S. epidermidis limits its growth and develops the ability to form biofilms.