Methicillin-resistant Staphylococcus aureus

Assessment of Methicillin-Resistant Staphylococcus aureus (MRSA) knowledge and awareness among healthcare workers in South-Lebanon

Background

Methicillin-Resistant Staphylococcus aureus (MRSA) is a well-known cause of hospital acquired infections (HAIs), associated with high rates of morbidity and mortality. In healthcare settings, MRSA can spread via contaminated surfaces and direct contact.

Objective

This study aims to assess the knowledge and awareness of MRSA risks, prevention methods (such as hand hygiene), proper antibiotics use, and multidrug resistance among various groups of healthcare workers (HCWs) in Southern Lebanon.

Methods

A total of 244 HCWs, including those in medical services (MS), paramedical services (PS), and non-medical services (NMS), were conveniently selected for this study. Data was gathered using a structured, validated questionnaire that explored their knowledge and awareness of MRSA risks, prevention measures, hand hygiene practices, and multidrug resistance.

Results

The findings revealed that 68% of HCWs were aware of the origin of MRSA infection, and 61.5% and 51.6% were familiar with its treatment and transmission, respectively. Only 24.2% of HCWs were able to differentiate between hospital-acquired and community-acquired MRSA, 14.7% were aware of the institution's written MRSA control protocols, and 17.6% had heard of MRSA infections. Notably, knowledge and hand hygiene practices were significantly better among MS HCWs than PS and NMS groups (P<0.0001). While all HCWs were familiar with antibiotic usage and drug resistance, NMS HCWs were more likely to use antibiotics without a prescription compared to MS and PS groups (P<0.003).

Conclusion

HCWs in South-Lebanon demonstrated a knowledge gap regarding MRSA risks and prevention guidelines. These findings underscore the need for targeted educational intervention on MRSA, as well as coordinated efforts by healthcare authorities and centres to control MRSA infections.

Construction of a thiophene-based conjugated polymer/TP-PCN S-scheme to enhance visible-light-driven photocatalytic activity: Promotion of wound healing in super-resistant bacterial infections

S-scheme heterojunctions have garnered significant attention in the field of photocatalytic antimicrobials due to their superior charge separation efficiency and higher redox capacity. In this study, an innovative linear conjugated polymer (PCO) was combined with fragmented carbon nitride (TP-PCN) to create PCO/TP-PCN organic-organic S-scheme heterojunctions, which markedly enhanced the photocatalytic antimicrobial performance. The composite (PCO-7/TP-PCN) demonstrated the ability to combat bacterial infections under visible light irradiation, effectively eradicating approximately 2.16 × 107 cfu/ml MRSA within 6 min. This exceptional photocatalytic performance can be attributed to the successful formation of an S-scheme heterojunction between PCO and TP-PCN, as well as the interaction of surface functional groups of PCO-7/TP-PCN with bacteria. Results from UV-Vis-NIR DRS and in situ-XPS experiments indicated a significant enhancement in carrier transport rate through the establishment of a built-in electric field and energy band bending at the interface. In vitro and in vivo experiments further demonstrated that PCO-7/TP-PCN not only exhibited potent antimicrobial activity under visible light irradiation but also promoted angiogenesis to inhibit inflammatory responses. Therefore, it can be concluded that this organic-organic S-scheme heterojunction photocatalyst holds great potential for development as a promising new generation of efficient antimicrobial materials, which could aid in preventing bacterial infection of wounds and ensuring effective wound healing.

A step forward on the in vitro and in vivo validation of rifabutin-loaded liposomes for the management of highly virulent MRSA infections

Staphylococcus aureus (S. aureus) infections, especially methicillin resistant (MRSA), constitute an alarming public health issue due to its association with high mortality, morbidity, and hospitalization costs. The increasing antibiotic resistance and biofilm-associated infections of MRSA prompted the discovery of novel and more effective therapeutic strategies. Our team has been working on alternative therapies against S. aureus infections. For this, we have been repurposing an existing antibacterial drug, rifabutin (RFB), through its association to a nanotechnological platform, liposomes, aiming to promote a preferential targeting to infected sites and maximizing its potential antibacterial effect. The therapeutic potential of RFB formulations against a MRSA commercial strain (MRSA ATCC®-33592), either in planktonic or biofilm forms, was assessed. RFB displayed higher antibacterial effects towards biofilm than vancomycin (VCM), the gold standard treatment against MRSA infections, with MBIC50 values of 103 and > 800 μg/mL, respectively. Moreover, the antimicrobial effect of RFB-loaded liposomes demonstrated to be lipid composition-dependent based on MIC50 and MBIC50 values, which was also confirmed by confocal laser scanning microscopy. These studies supported that for positively charged RFB liposomes an electrostatic interaction at biofilm surface occurs without internalization. On the other hand, for RFB-loaded liposomes with neutral surface charge a high internalization within the biofilm was observed. Moreover, this RFB liposomal formulation has also demonstrated to be stable in human plasma, as more than 83 % of RFB was still associated to liposomes 24 h after incubation at 37 °C. The proof of concept of RFB formulations was assessed in MRSA systemic murine models of infection. Therapeutic effect and survival rates were evaluated for animals induced and treated with RFB in free and liposomal forms and compared with negative and positive controls. For the lower infection murine model, 100 % survival was achieved for all groups under study. However, in a higher infection model only for the group of animals treated with RFB incorporated in liposomes a 100 % survival was attained. In terms of bacterial burden, RFB formulations exhibited lower levels when compared to VCM, even using a lower therapeutic dose: 20 vs 40 mg/kg of body weight, respectively. Overall, RFB constitutes an alternative and effective therapeutic strategy towards MRSA infections, being this effect potentiated through its association to a lipid nanoplatform.

Combination therapy delays antimicrobial resistance after adaptive laboratory evolution of Staphylococcus aureus

Antibiotic resistance, driven by misuse and overuse of antibiotics, is one of the greatest threats against human health. The antimicrobial pressure during prolonged antibiotic treatment of chronic bacterial infections selects for resistance. While antibiotic combinations may reduce resistance emergence, antibiotic-tolerant persister cells can serve as a reservoir for resistance development. Therefore, targeting these cells with anti-persister drugs might provide a novel strategy for resistance prevention. In this study, we conducted 42 days of adaptive laboratory evolution using Staphylococcus aureus exposed to rifampicin, ciprofloxacin, daptomycin, and vancomycin, alone or in combination with the anti-persister drug mitomycin C. We monitored antibiotic susceptibility daily and assessed phenotypic changes in growth and biofilm formation in evolved strains. Whole-genome sequencing revealed mutations linked to antibiotic resistance and phenotypic shifts. Rifampicin resistance developed within a few days, while ciprofloxacin and daptomycin emerged in approximately 3 weeks. Treatments with vancomycin or mitomycin C resulted in minimal changes in susceptibility. While combination therapy delayed resistance, it did not fully prevent it. Notably, the combination of rifampicin with mitomycin C maintained rifampicin susceptibility throughout the long-term evolution experiment. Sub-inhibitory antibiotic treatments selected for both previously characterized and novel mutations, including unprecedented alterations in the nucleotide excision repair system and azoreductase following mitomycin C exposure. The delayed resistance development observed with combination therapy, particularly mitomycin C's ability to suppress rifampicin resistance, suggests potential therapeutic applications. Future studies should evaluate the clinical efficacy of anti-persister drugs in preventing resistance across different bacterial pathogens and infection models.

A computational investigation of potential plant-based bioactive compounds against drug-resistant Staphylococcus aureus of multiple target proteins

Drug-resistant Staphylococcus aureus (DRSA) poses a significant global health threat, like bacteremia, endocarditis, skin, soft tissue, bone, and joint infections. Nowadays, the resistance against conventional drugs has been a prompt and focused medical concern. The present study aimed to explore the inhibitory potential of plant-based bioactive compounds (PBBCs) against effective target proteins using a computational approach. We retrieved and verified 22 target proteins associated with DRSA and conducted a screening process that involved testing 87 PBBCs. Molecular docking was performed between screened PBBCs and reference drugs with selected target proteins via AutoDock. Subsequently, we filtered the target proteins and top PBBCs based on their binding affinity scores. Furthermore, molecular dynamic simulation was carried out through GROMACS for a duration of 100 ns, and the binding free energy was calculated using the gmx_MMPBSA. The result showed consistent hydrogen bonding interactions among the amino acid residues Ser 149, Arg 151, Thr 165, Thr 216, Glu 239, Ser 240, Ile 14, as well as Asn 18, Gln 19, Lys 45, Thr 46, Tyr 109, with their respective target proteins of the penicillin-binding protein and dihydrofolate reductase complex. Additionally, we assessed the pharmacokinetic properties of screened PBBCs via SwissADME and AdmetSAR. The findings suggest that β-amyrin, oleanolic acid, kaempferol, quercetin, and friedelin have the potential to inhibit the selected target proteins. In future research, both in vitro and in vivo, experiments will be needed to establish these PBBCs as potent antimicrobial drugs for DRSA.

Success rates of decolonisation treatment and risk factors for chronic carriage in methicillin-resistant Staphylococcus aureus throat carriers: a retrospective population-based cohort study

BACKGROUND

Throat carriage of methicillin-resistant Staphylococcus aureus (MRSA) has previously been associated with lower decolonisation treatment success rates.

OBJECTIVES

To characterise decolonisation treatment and outcome in Danish MRSA throat carriers.

METHODS

This retrospective population-based cohort study included MRSA throat carriers between July, 2018 and June, 2019, in the Capital Region of Denmark. Logistic regression analysis was performed to assess variables associated with becoming MRSA free.

RESULTS

Of 178 patients included, 129 (72%) were MRSA free by the end of the study. Overall, 78 (44%) of patients became MRSA free following a treatment attempt. Twenty-six (15%) patients became MRSA free without treatment and 25 (14%) became MRSA free unrelated to a treatment attempt. The success rate of the first decolonisation treatment, mainly nasal mupirocin and chlorhexidine body wash, was 23%. Systemic clindamycin was given in 52 cases and had a success rate of 52%. Logistic regression showed that residing in a household with three to four additional MRSA carriers was negatively associated with becoming MRSA free, although not significant after adjustment. Having MRSA in a clinical sample prior to decolonisation was associated with a lower chance of becoming MRSA free after adjustment. Topical decolonisation treatment was associated with a lower probability of becoming MRSA free.

CONCLUSION

In this Danish cohort of MRSA throat carriers, the overall success rate of decolonisation treatment was 44% and for systemic clindamycin 52%. A higher number of household MRSA carriers and a previous clinical MRSA infection were associated with a lower chance of becoming MRSA free.

Pathogenic characterization and drug resistance of neonatal sepsis in China: a systematic review and meta-analysis

OBJECTIVES

Neonatal sepsis is one of the causes of neonatal mortality and bacterial resistance to antibiotics is one of the challenges facing NICU. The aim of this study was to provide a basis for empirical antibiotic selection by comprehensively searching Chinese and non-Chinese databases for studies related to neonatal sepsis pathogenesis conducted in China and synthesizing all the results of the studies conducted in hospitals in China during the period under study METHODS: In this study, we conducted extensive searches of Pubmed, Web of Science, Cochrane, China Biology Medicine disc (SinoMed), China National Knowledge Infrastructure (CNKI) and Wanfang Data. We screened studies published from 2014 to 2023 that were conducted in hospitals in mainland China and involved bacterial blood cultures and susceptibility tests in neonates with neonatal sepsis and extracted the data, which were summarized using Stata 18.0 software to determine the bacterial characteristics of NS and its antimicrobial resistance in China.

RESULTS

A total of 97 articles were finally included in the study, involving 27 provinces, municipalities and autonomous regions, and a total of 18,796 bacterial strains were isolated. Among them, Gram-positive bacteria (G+) accounted for 63.4% (95% CI 59.6%~67.3% ), and Gram-negative bacteria (G-) accounted for 36.6% (95% CI 32.7%~40.4%). The most common bacteria were, in order, Coagulase-negative Staphylococcus (43.6%, 95% CI 37.9-49.3%), Enterobacter (16.4%, 95% CI 14.8-18.1%), and Klebsiella (12.4%, 95% CI 10.8-14.0%). More than 80% of G + were resistant to penicillin, ampicillin, and benzathine, and no strains resistant to minocycline or daptomycin were found. More than 80% of G- were resistant to benzoxicillin, ampicillin, and cefotaxime, and no strains resistant to vancomycin, clindamycin, tigecycline, teicoplanin, and linezolid were identified.

CONCLUSION

Coagulase-negative Staphylococcus is still the main causative agent for children with neonatal sepsis in China, followed by Enterobacter and Klebsiella. In addition, Group B Streptococcus is no longer in the top three common causative agents. Resistance to penicillin antibiotics is evident among the causative organisms of neonatal sepsis in China.

Potential activity of paroxetine alone and associated with oxacillin as an alternative to prevent Staphylococcus aureus biofilm formation in catheters

Biofilm formation, especially in medical devices, is a pertinent factor in the virulence of Staphylococcus aureus, and is known to increase morbidity, mortality, and costs. We evaluated the activity of paroxetine, a selective serotonin reuptake inhibitor, alone and associated with oxacillin, a β-lactam antibacterial, against S. aureus biofilms, as well as verified its potential application as a preventive agent against biofilm formation in catheters. The tests were performed against mature and developing biofilms of methicillin-sensitive and -resistant S. aureus using the thiazolyl blue tetrazolium bromide reduction assay. The prevention of biofilm formation in catheters was investigated by counting colony-forming units, and scanning electron microscopy was also performed. Paroxetine caused a significant reduction in cell viability in biofilms, and when associated with oxacillin, significance was verified. Paroxetine alone and associated with oxacillin showed potential for preventing the formation of S. aureus biofilms in peripheral venous catheters, demonstrated by scanning electron microscopy, reaching inhibition of 94.94% in colony-forming units per mL. Paroxetine demonstrated promising potential against S. aureus biofilms in vitro, indicating the possibility of application as a protective agent against the formation of S. aureus biofilms in catheters.

Exploration of Novel Antimicrobial Agents against Foodborne Pathogens via a Deep Learning Approach

The emergence of antibiotic-resistant bacteria poses a severe threat to food safety and human health, necessitating an urgent search for novel antimicrobial agents that can be applied in the food industry. This study utilizes a deep learning approach to establish the optimal models for antibacterial activity against foodborne pathogens, particularly Escherichia coli and Staphylococcus aureus, as well as for predicting carcinogenicity. These optimal models are applied to screen natural products from the COCONUT database, resulting in the identification of 130 compounds with both antibacterial activity and noncarcinogenic properties. Two natural products, bis(hexamethylene)triamine and N-phenethylbiguanide, are selected for experimental validation of their antibacterial activity. The confirmation of antimicrobial properties validates the reliability of the models developed in this study. By providing an innovative approach for identifying antimicrobial agents for foodborne pathogens, this research offers new insights for discovering effective antimicrobials in an efficient manner.

Characterization and host range prediction of Staphylococcus aureus phages through receptor-binding protein analysis

Bacteriophages are crucial in bacterial communities and can be used for therapy of multidrug-resistant pathogens such as Staphylococcusaureus. However, the host range of new phages remains difficult to predict. We identified the receptor-binding proteins (RBPs) of 335 S. aureus-infecting phages, yielding 8 distinct RBP clusters. Recombinant representative RBPs of all clusters, including several subclusters, were analyzed for binding to S. aureus strains differing in potential phage receptor structures. Notably, most of the phages encoded two separate RBPs, and all RBPs used S. aureus wall teichoic acid (WTA) polymers as receptors, albeit with varying preference for WTA glycosylation patterns and backbone structures. Based on these findings, a sequence-based tool for predicting the adsorption of new phages was developed. Moreover, one of the RBPs proved useful for identifying S. aureus-type WTA in other bacterial species. These findings facilitate the characterization of phage and bacterial isolates and the development of phage therapies.

Dual proximity ligation mediated chain extension and displacement assisted signal cycles for sensitive and accurate methicillin-resistant Staphylococcus aureus (MRSA) detection

Infectious diseases have emerged as a significant global concern, posing a substantial burden in terms of high morbidity and mortality and presenting considerable challenges in clinical diagnosis and treatment. Therefore, it is highly desired to develop new strategies for sensitive and accurate bacteria detection to address the global epidemic of antibiotic resistance. In this study, a new technique utilizing a dual proximity ligation mediated chain extension and displacement strategy was developed for precise identification and highly sensitive detection of Methicillin-Resistant Staphylococcus aureus (MRSA). The antibodies recognize both protein A and PBP2a on the surface of MRSA, leading to the initiation of proximity ligation and signal amplification processes. The signal amplification procedure generated a substantial number of G-quadruplex sequences, which subsequently bind with thioflavin T (ThT) to significantly amplify its fluorescence, enabling the detection of MRSA with a low detection limit of 3.5 cfu mL-1. In this method, dual proximity ligation assays were integrated to mediate the signal amplification process, thus endowing the method with a greatly elevated specificity in both MRSA identification and signal amplification. Due to its non-label format, high selectivity, and sensitivity, this method can serve as a practical and versatile approach for detecting different bacteria in the early stages of infectious diseases.

Lasso peptides sviceucin and siamycin I exhibit anti-virulence activity and restore vancomycin effectiveness in vancomycin-resistant pathogens

Antibiotic resistance is a major threat to human health and new drugs are urgently needed. Ideally, these drugs should have several cellular targets in pathogens, decreasing the risk of resistance development. We show here that two natural ribosomally synthesized lasso peptides (LPs), sviceucin and siamycin I, (1) abolish bacterial virulence of pathogenic enterococci, (2) restore vancomycin clinical susceptibility of vancomycin-resistant (VR) enterococci in vitro and in a surrogate animal model, and (3) re-sensitize VR Staphylococcus aureus. Mode of action (MoA) analyses showed that they do so by inhibiting the histidine kinases (HKs) FsrC and VanS controlling these phenotypes. Strains resistant to the vancomycin/LP combination were difficult to obtain, and were still fully susceptible to the anti-virulence effect of the LPs, highlighting the advantage of multiple targets. Together with the highly sought-after MoA as HK inhibitors, such properties make these lasso peptides promising candidates for the development of next generation antibiotics.

Study on molecular characteristics of Staphylococcus from yak milk-Xizang

This study investigated the biological characteristics of Staphylococcus strains isolated from Xizangan yak milk by examining the antibiotic resistance phenotypes of 69 isolates against 18 antibiotics, detecting 31 associated resistance genes, identifying 16 virulence genes, and assessing biofilm formation capability. Furthermore, molecular typing techniques including spa typing, multilocus sequence typing (MLST), and Staphylococcus cassette chromosome mec (SCCmec) were used for detailed characterization of the isolates. The findings revealed a high penicillin resistance rate of 72.46%. Resistance genes such as gyrA (100.00%), glrB (92.75%), and gyrB (44.93%) were prevalent. The detection rates were 81.16% and 55.07% for the beta-lactamase gene blaZ and the mecA gene, respectively. Among the tested virulence genes, lukS, lukF, hla, clfA, and icaD were detected in 40.58% of isolates, while sec was detected in 24.64%. MLST typing identified four isolates belonging to the ST62623 type and 24 other isolates representing novel ST types not reported on PubMLST.org. Spa typing revealed spa types t1940 (n = 9), t3022 (n = 8), t4558 (n = 6), t4236 (n = 3), t4445 (n = 1), and one unreported spa type. For SCCmec typing, 11 isolates were typed as SCCmec IVb and 9 as SCCmec V. These findings significantly enhance our understanding of the biological characteristics of Staphylococcus strains derived from Xizangan yak milk.

Antibacterial Effects of Synthetic Plantaricins Against Staphylococcus aureus

Background/Objectives: Plantaricins without a signal sequence were synthesized based on bacteriocins, plantaricins A, E, F, J, and K, of Lactiplantibacillus plantarum KM2. The antibacterial activities of four combinations of synthetic plantaricins-spPlnA, E&F, E&J, and J&K-were identified against Staphylococcus aureus ATCC 12692. And in this experiment, we aimed to identify the antimicrobial mechanism of the synthesized plantaricin sample against S. aureus. Methods/Results: The minimal inhibitory concentrations for each combination were 1.4 μg/mL, 1.8 μg/mL, 1.6 μg/mL, and 1.6 μg/mL, respectively. Raman spectra changed after treating S. aureus ATCC 12692 with synthetic plantaricins. Furthermore, transmission electron microscopy results revealed that the four synthetic plantaricin combinations could induce the cell lysis of S. aureus ATCC 12692. Finally, the four synthetic plantaricin combinations maintained their antibacterial effect at temperatures below 40 °C, and at pH levels of pH = (4-7). Except for spPlnJ&K, they are stable against the action of α-amylase and lysozyme. Overall, these results indicate that, excepting spPlnJ&K, the three synthetic plantaricin combinations exhibit similar antibacterial activity. Conclusions: Through this study, we confirmed that synthetic plantaricin exhibited antimicrobial activity against S. aureus, demonstrating its potential as a direct antimicrobial agent. However, since the antimicrobial activity decreased due to protease, it was confirmed that its use is limited in environments where protease is present.

Phytochemical-Loaded Thermo-responsive Liposome for Synergistic Treatment of Methicillin-Resistant Staphylococcus aureus Infection

The ever-increasing emergence and prevalence of multidrug-resistant bacteria accelerate the desire for the development of new antibacterial strategies. Although antibacterial phytochemicals are a promising approach for long-term treatment of resistant bacteria, their low antibacterial activity and poor solubility hinder their practical applications. Here, the natural antibacterial compound sanguinarine (SG) together with gallic acid-ferrous coordination nanoparticles (GA-Fe(II) NPs) was encapsulated in a near-infrared (NIR)-activated thermo-responsive liposome. By virtue of the photothermal effect of GA-Fe(II) NPs, the nanoplatform released SG on demand upon NIR irradiation. Additionally, the heat can boost the Fenton reaction triggered by GA-Fe(II) NPs to generate hydroxyl radicals and perform sterilization. By coupling with photothermal therapy, chemodynamic therapy, and SG-based pharmacotherapy, the platform showed enhanced antibacterial efficiency and an antibiofilm effect toward methicillin-resistant Staphylococcus aureus and reduced the risk of developing new bacterial resistance. This antibacterial system displayed excellent antibacterial activity in a methicillin-resistant S. aureus-caused skin abscess, demonstrating its potential clinical application. Moreover, transcription analysis clarified that the platform achieved a synergistic antibacterial effect by attacking the cell membrane, inducing energy metabolism disorder, inhibiting nucleic acid synthesis, etc. The developed NIR-controlled phytochemical-loaded platform offers new possibilities for killing antibiotic-resistant bacteria and avoiding bacterial resistance, making it contributory in the fields of anti-infective therapy and precision medicine.

Photothermal Antibacterial Therapy of Near-Infrared II Region Laser Mediated by Gold Hollow Nanorod

The current traditional treatment for bacterial infections is to treat them with antibiotics, and the misuse of antibiotics can lead to an increase in bacterial resistance. In contrast, the development of new antibiotics is much slower than the speed of adaptation of drug-resistant bacteria, making it necessary to develop a drug that does not rely on antibiotics. Therefore, based on the advantages of photothermal therapy, NIR II-responsive gold hollow nanorods (GHNRs) were developed to overcome the limitation of bacterial drug resistance in conventional bacterial therapy. GHNRs can quickly respond to a 980 nm laser with a high photothermal conversion efficiency of 41.78%. The high temperature produced by GHNRs can effectively kill Staphylococcus aureus and Escherichia coli, providing a new strategy for the clinical treatment of bacterial infectious diseases without antibiotic dependence.

Antimicrobial photodynamic therapy with 5-aminolevulinic acid plus antibiotics: a promising treatment for tibial osteomyelitis caused by drug-resistant bacteria

Osteomyelitis is a severely destructive bone disease caused by microbial infections, and currently, no available treatment effectively controls the infection. 5-Aminolevulinic acid is a second-generation endogenous photosensitizer. This study investigated the efficacy of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) in combination with antibiotics in the treatment of tibial osteomyelitis in rabbits. The results illustrated that ALA-PDT alone and in combination of antibiotics displayed significant efficacy in treating osteomyelitis. Animals in the photodynamic antimicrobial chemotherapy (PACT) + antibiotics group exhibited a higher survival rate, an improved overall mental status, a lower localized infection rate, and reduced Tang Hui and Norden scores (P < 0.05), indicating less severe bone destruction. Histologically, more strips of lamellar new bone formation and more pronounced periosteal hyperplasia were noted in the PACT + antibiotics group. Micro-computed tomography illustrated that the structural integrity of cortical bone and cancellous bone structure had better continuity and clearer display in the PACT + antibiotics group than in the other groups, and the periosteal reaction in the modeling area was the most obvious. Bone parameter analysis indicated that trabecular thickness, bone volume, and trabeculae volume were significantly higher in the PACT + antibiotics group than in the model and antibiotics groups (P < 0.05). Additionally, trabecular separation was significantly lower in the PACT + antibiotic group than in the other groups (P < 0.05). These findings suggest that the combination of ALA-PDT and antibiotics has a sensitizing therapeutic effect, offering a promising strategy for the clinical treatment of osteomyelitis.

IL-24 promotes atopic dermatitis-like inflammation through driving MRSA-induced allergic responses

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder in which patients experience recurrent eczematous lesions and intense itching. The colonization of Staphylococcus aureus (S. aureus) is correlated with the severity of the disease, but its role in AD development remains elusive. Using single-cell RNA sequencing, we uncovered that keratinocytes activate a distinct immune response characterized by induction of Il24 when exposed to methicillin-resistant S. aureus (MRSA). Further experiments using animal models showed that the administration of recombinant IL-24 protein worsened AD-like pathology. Genetic ablation of Il24 or the receptor Il20rb in keratinocytes alleviated allergic inflammation and atopic march. Mechanistically, IL-24 acted through its heterodimeric receptors on keratinocytes and augmented the production of IL-33, which in turn aggravated type 2 immunity and AD-like skin conditions. Overall, these findings establish IL-24 as a critical factor for onset and progression of AD and a compelling therapeutic target.

Molecular characterization of methicillin-susceptible/resistant Staphylococcus aureus from bloodstream infections in northern Japan: The dominance of CC1-MRSA-IV, the emergence of human-associated ST398 and livestock-associated CC20 and CC97 MSSA

OBJECTIVES

Staphylococcus aureus (S. aureus) is a major cause of bloodstream infections. The recent epidemiological features and antimicrobial resistance trend were analysed for methicillin-resistant and susceptible S. aureus (MRSA/MSSA) isolates from blood samples in people from northern Japan.

METHODS

The S. aureus isolates from blood culture were screened by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and genotyped by the schemes of multilocus sequence typing (MLST), coa, agr, spa, and SCCmec types. Antimicrobial resistance genes and virulence factors were detected by multiplex/uniplex polymerase chain reaction (PCR). Antimicrobial susceptibility was examined using a broth microdilution test.

RESULTS

A total of 301 isolates (163 MRSA and 138 MSSA) were isolated from bloodstream infections in 2023 (from April to December). The MRSA isolates were classified into three groups, that is, clonal complexes (CC)1-SCCmec-IV (CC1-IV) (52%), CC5-II (36%), and CC8-IV (12%). The prevalence of CC1 was significantly higher than those in our previous studies (2017-2021). Four CC8-IVa isolates with PVL genes on ΦSa2usa were considered to be the USA300 clone (sequence type [ST]8/spa-t008/coa IIIa/agr I) or its variants that were genotyped as those closely related to ST8/t008 or lacking arginine catabolic mobile element (ACME). In contrast, MSSA was genetically highly divergent and classified into 22 STs, with CC1 (ST1 and ST188) being the most common (25%). It was notable that 29 MSSA isolates (21%) were classified into livestock-associated (LA) genotypes, ST20, ST97, and CC398 (ST398 and ST291). Genetic characterization of the CC398 isolates suggested that these belong to human-adapted MSSA clones.

CONCLUSIONS

The present study revealed the increasing trend of CC1 MRSA surpassing CC5, and the emergence of MSSA representing human-adapted CC398, and LA types ST97 and ST20 from bloodstream infections in people in Japan. © 2024 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.

Deprotonation-Constructed Instant Gelation Coating for Staphylococcus Disinfection and Preservation of Fresh Food in Multiple Scenarios

The ancient proverb "disease enters through the mouth" elucidates the connection between food and pathogens, underscoring the pivotal role of food preservation in preventing foodborne diseases. Drawing inspiration from ancient food preservation techniques such as waxing and the use of spices, a novel approach combining the deprotonation-induced solid-liquid phase separation of natural polymer solutions with the solubilization of plant-derived antibacterial compounds has been developed. The "two-step soaking" construction strategy enables the creation of biodegradable and adaptable for hydrogel coatings with micro-scale thickness. These multifunctional coatings can be applied to the surfaces of fresh fruits, vegetables, and meats in 35 s, providing both moisture retention and antioxidant protection. The coating's versatility allows for the targeted can achieve the elimination of various Staphylococcus and other bacterial strains through the selection of bactericides with differing antibacterial mechanisms. The scalability of this approach offers significant potential for broad applications in sterilization and food preservation in across diverse contexts.

Identification of Potential PBP2a Inhibitors Against Methicillin-Resistant Staphylococcus aureus via Drug Repurposing and Combination Therapy

Methicillin-resistant Staphylococcus aureus (MRSA) achieves high-level resistance against β-lactam antibiotics through the expression of penicillin-binding protein 2a (PBP2a), which features a closed active site that impedes antibiotic binding. Herein, we implemented a strategy that combines drug repurposing with synergistic therapy to identify potential inhibitors targeting PBP2a's allosteric site from an FDA-approved drug database. Initially, retrospective verifications were conducted, employing different Glide docking methods (HTVS, SP, and XP) and two representative PBP2a structures. The combination of Glide SP and one representative PBP2a conformation showed the highest efficacy in identifying active compounds. The optimized parameters were then utilized to screen FDA-approved drugs, and 15 compounds were shortlisted for potential combination therapy with cefazolin, an ineffective cephalosporin against MRSA. Through biological assays-checkerboard, time-kill assays, and live/dead bacterial staining-we discovered that four compounds exhibited robust bactericidal activity (FICI < 0.5) compared to both untreated control and monotherapy with cefazolin alone. Scanning electron microscopy (SEM) confirmed that while cefazolin alone did not cause visible damage to MRSA cells, the combination treatment markedly induced cell lysis. Additional MM-GBSA studies underscored the strong binding affinity of mitoxantrone to the allosteric site. These findings introduce a combination therapy approach that potentially restores MRSA's susceptibility to β-lactam antibiotics.

Staphylococcus aureus: Dynamics of pathogenicity and antimicrobial-resistance in hospital and community environments - Comprehensive overview

This study reviews Staphylococcus aureus, a significant pathogen in both hospital and community-acquired infections, addressing its epidemiology, pathogenesis, and antimicrobial resistance. It highlights virulence mechanisms, such as adhesion factors, toxins, enzymes, and biofilms, which contribute to survival and immune evasion. The spread of resistance occurs through the transfer of mobile genetic elements like SCCmec and genetic mutations. The analysis also compares hospital and community strains, including multidrug-resistant lineages like MRSA, VISA, and VRSA. The study concludes that S. aureus presents a major public health challenge, requiring new therapeutic approaches and preventive strategies.

Clonal dissemination of methicillin-resistant Staphylococcaceae between Algerian sheep farms

OBJECTIVES

Sheep farming represents an important economic sector in Algeria, and the potential dissemination of methicillin-resistant Staphylococcaceae (MRS) is a critical veterinary and public health concern. This study aimed to determine the prevalence and types of MRS in ovine in Algeria and characterize them using whole-genome sequencing (WGS) analysis.

METHODS

Two hundred sheep from 20 different Algerian farms across 3 regions were screened for nasal colonization with MRS. The isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), their minimal inhibitory concentration (MIC) was determined by broth microdilution, and the presence of the mec gene was confirmed with polymerase chain reaction (PCR). The mec-positive isolates were sequenced using Illumina technology to build species specific core genome multilocus sequence typing (cgMLST)- and single nucleotide polymorphisms (SNPs)-based phylogenies and perform an in silico screening for antimicrobial resistance genes.

RESULTS

The prevalence of MRS-positive farms was 85% (95% confidence interval [CI] = 69.34%-100%) across the sampled farms. Ten distinct Staphylococcaceae species were identified, with Staphylococcus saprophyticus (S. saprophyticus; n = 29), Mammaliicoccus lentus (M. lentus; n = 24), and Staphylococcus haemolyticus (S. haemolyticus; n = 19) being the predominant species. WGS-based phylogeny and SNP analysis (0 to 126 SNPs) revealed that isolates of these three species were highly related, indicating clonal dissemination within and between farms. MRS exhibited a multi-drug resistance pattern, with detection of resistance genes for β-lactams, tetracyclines, fusidic acid, trimethoprim, aminoglycosides, tiamulin, and macrolides.

CONCLUSIONS

Specific clonal lineages of methicillin-resistant S. saprophyticus, S. haemolyticus, and M. lentus are widespread in Algerian sheep farms. Enhancing hygiene practices on farms is recommended to prevent further dissemination of these resistant strains to animals and humans. © 2025 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.

Evaluation of aminoglycoside- and methicillin-resistant Staphylococcus aureus: phenotypic and genotypic insights from clinical specimens in Ardabil, Iran

BACKGROUND

Combination therapy including an aminoglycoside antibiotic and a cell-wall active agent is considered the most suitable option to treat invasive infections with methicillin-resistant Staphylococcus aureus (MRSA). Dual drug therapy enhances the effectiveness of treatment and reduces the risk of resistance development. This study aims to elucidate the phenotypic and molecular resistance to aminoglycosides and methicillin, and the molecular epidemiologic characteristics of S. aureus in Ardabil northwest Iran.

METHODS

Totally, 118 S. aureus isolates collected from clinical specimens were investigated. Identification was performed using standard microbiological and molecular approaches. Aminoglycoside and methicillin resistance were evaluated using the disk diffusion assay, and the minimum inhibitory concentrations (MICs) of aminoglycosides were determined via the agar dilution method. The mecA gene encoding methicillin resistance and aminoglycoside modifying enzymes (AMEs) genes were detected using PCR. Molecular epidemiologic features of the isolates were determined using staphylococcal cassette chromosome mec (SCCmec) typing spa typing and ERIC-PCR assays.

RESULTS

Of the isolates, 42.4% (n = 50) and 57.6% (n = 68) were identified as MRSA and MSSA, respectively. All MRSA isolates were mecA-positive. Among MRSA isolates, SCCmec type IVa (17; 34%) was predominant, followed by types IVc, V, III, II, and I. Resistance rates to gentamicin, kanamycin, tobramycin, and amikacin were 16.1%, 17.8%, 8.5%, and 8.5%, respectively. Overall, the aminoglycoside resistance and most non-aminoglycoside antibiotics were significantly higher in MRSA versus MSSA isolates. The prevalence of AME genes was as follows: aac(6')-Ie-aph(2'') (30; 76.9%), aph(2'')-Ib (22; 56.4%), and ant(4')-Ia (14; 35.9%). About 60% of aminoglycoside-resistant isolates harbored ≥ 2 AME genes. The t030 type was the most common spa type identified. The ERIC-PCR profiles categorized the isolates into 19 unique ERIC types.

CONCLUSIONS

This study reveals high aminoglycoside and methicillin resistance in S. aureus isolates from Ardabil hospitals. Predominant SCCmec type IVa and spa type t030 indicate specific molecular patterns. These findings highlight the need for continuous surveillance and targeted treatment strategies for MRSA infections.

CLINICAL TRIAL NUMBER

Not applicable.

Engineered Nanovesicles for the Precise and Noninvasive Treatment of Deep Osteomyelitis Caused by MRSA Infection with Enhanced Immune Response

The clinical treatment of hospital-acquired persistent osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA) presents two major challenges: ineffective drug delivery into deep tissues and counteracting the rapid establishment of an immunosuppressive microenvironment. Indeed, MRSA can evade immunosurveillance and undermine both innate and adaptive immune responses. Herein, the engineered nanovesicles, functioning by combining sonodynamic therapy (SDT) with immune modulation, were constructed for the precise and noninvasive removal of MRSA in deep tissue and activation of the antimicrobial immune response using a newly engineered nanovesicle. Macrophage-derived M1 phenotypic microvesicles (M1-MW) internalized vancomycin-cross-linked micelles with the acoustic sensitizer indocyanine green (ICG) (VCG micelles). The vesicles of M1-MW were grafted with PEGylated mannose, allowing for targeted accumulation at the infection site. The VCG micelles were responsive to the highly reducing environment and released ICG to generate ROS after exposure to ultrasounds. This effect was combined with the presence of vancomycin to kill MRSA. In an osteomyelitis infection model, we observed an improved survival rate and reprogramming of macrophages to a pro-inflammatory M1 phenotype. The latter promoted T-cell activation and immune defense against MRSA-camouflaged homologous cell-transferred infections. Thus, our study presents a noninvasive and efficient treatment (VCG@MMW) for deep osteomyelitis with improved bacterial clearance and reduced risk of recurrence with enhanced immune response.

Staphylococcus aureus infections in a highly complex clinic in Colombia. A longitudinal retrospective observational study

BACKGROUND

Antimicrobial resistance is a public health problem. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the microorganisms most responsible for illness and death. The aim was to characterize the infections caused by S. aureus and to determine the factors associated with in-hospital mortality in patients treated in a highly complex clinic in Colombia.

METHODS

This was a longitudinal retrospective observational study of patients with culture-confirmed S. aureus infections who received hospital care between 2018 and 2023. Follow-up was carried out until the patients died or were discharged from the clinic. Descriptive, bivariate and multivariate analysis was performed.

RESULTS

A total of 361 patients were included; 62.6 % were men, and the mean age was 49.2 years. Most patients were diagnosed with skin and soft tissue infections (51.0 %) and bacteremia (25.5 %). The most used antibiotics were clindamycin (53.5 %) and vancomycin (42.7 %). A total of 46.3 % had MRSA infections and 25.8 % were resistant to clindamycin, 37.7 % of the patients received care in the intensive care unit, 33.2 % had sepsis, 19.1 % required invasive mechanical ventilation, and 13.9 % died. Higher Charlson comorbidity index (aOR:1.45; 95%CI:1.04-2.02), higher Pitt Bacteremia Score (aOR:1,72; 95%CI:1.21-2.46) and bacteremia (aOR:5.30; 95%CI:1.44-19.41) increased the probability of death. Those who were empirically managed with antibiotics that had coverage for MRSA (aOR:0.03; 95%CI:0.00-0.24) and higher levels of hemoglobin (aOR:0.75; 95%CI:0.65-0.87) had a lower risk of death.

CONCLUSION

MRSA infections are frequent, with significant resistance to clindamycin. The identification of variables associated with a higher risk of dying may be useful for establishing protocols in hospitals that reduce this outcome.

Natural peptides and their synthetic congeners acting against Acinetobacter baumannii through the membrane and cell wall: latest progress

Acinetobacter baumannii is one of the deadliest Gram-negative bacteria (GNB), responsible for 2-10% of hospital-acquired infections. Several antibiotics are used to control the growth of A. baumannii. However, in recent decades, the abuse and misuse of antibiotics to treat non-microbial diseases have led to the emergence of multidrug-resistant A. baumannii strains. A. baumannii possesses a complex cell wall structure. Cell wall-targeting agents remain the center of antibiotic drug discovery. Notably, the antibacterial drug discovery intends to target the membrane of the bacteria, offering several advantages over antibiotics targeting intracellular systems, as membrane-targeting agents do not have to travel through the plasma membrane to reach the cytoplasmic targets. Microorganisms, insects, and mammals produce antimicrobial peptides as their first line of defense to protect themselves from pathogens and predators. Importantly, antimicrobial peptides are considered potential alternatives to antibiotics. This communication summarises the recently identified peptides of natural origin and their synthetic congeners acting against the A. baumannii membrane by cell wall disruption.

Eradication of Antibiotic-Resistant Gram-Positive Bacteria and Biofilms by Rationally Designed AIE-Active Iridium(III) Complexes Derived from Cyclometalating 2-Phenylquinoline and Ancillary Bipyridyl Ligands

Antibiotic resistance caused by Gram-positive bacteria is a growing global human health threat. Selective discrimination and eradication of Gram-positive bacteria and their biofilms is challenging. Therapeutic strategies with multiple modes of action are urgently needed to address the increase in Gram-positive bacteria-resistant nosocomial infections. In this work, we have presented rationally designed aggregation-induced emission (AIE)-active cationic cyclometalated iridium(III) complexes derived from 2-phenylquinoline and 2,2'-bipyridine ligands for Gram-positive antibacterial studies. The AIE properties of these complexes were exploited for selective discrimination between Gram-positive and Gram-negative bacteria. These complexes displayed good antimicrobial activity against critical Gram-positive ESKAPE pathogens with minimum inhibitory concentrations in the low micromolar range but were inactive against Gram-negative pathogens. Importantly, the complexes can inhibit biofilm formation and eradicate bacteria from mature biofilms, which are major causes of persistent infections and antibiotic resistance and are more difficult to eliminate. In addition, these complexes showed low hemolytic activity against mammalian cells and a high therapeutic index, indicating good selectivity. Interestingly, the complexes kill bacteria through a variety of modes of mechanism, including ROS generation, cell membrane disruption, and depolarization and the loss of bacterial membrane integrity. These findings offer opportunities for designing metal AIEgens to treat Gram-positive bacterial infections effectively.

Unravelling the advances of CRISPR-Cas9 as a precise antimicrobial therapy: A systematic review

Antimicrobial resistance is a critical public health threat, compromising treatment effectiveness. The spread of resistant pathogens, facilitated by genetic variability and horizontal gene transfer, primarily through plasmids, poses significant challenges to health systems.

OBJECTIVE

This review explores the potential of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology and Cas9 nucleases in combating antimicrobial resistance.

METHODS

The literature review followed the PRISMA guidelines using PubMed, Embase, and Scopus databases until July 2023.

RESULTS

The Enterobacterales family, particularly Escherichia coli, was the main focus. The resistance genes targeted were mainly associated with β-lactam antibiotics, specifically bla genes, and colistin resistance linked to the mcr-1 gene. Plasmid vectors have been the primary delivery method for the CRISPR-Cas9 system, with conjugative plasmids resensitizing bacterial strains to various antimicrobials. Other delivery methods included electroporation, phage-mediated delivery, and nanoparticles. The efficacy of the CRISPR-Cas9 system in resensitizing bacterial strains ranged from 4.7% to 100%.

CONCLUSIONS

Despite challenges in delivery strategies and clinical application, studies integrating nanotechnology present promising approaches to overcome these limitations. This review highlights new perspectives for the clinical use of CRISPR-Cas9 as a specific and efficient antimicrobial agent, potentially replacing traditional broad-spectrum antimicrobials in the future.

Staphylococcus aureus in Inflammation and Pain: Update on Pathologic Mechanisms

Staphylococcus aureus (S. aureus) is a Gram-positive bacterium of significant clinical importance, known for its versatility and ability to cause a wide array of infections, such as osteoarticular, pulmonary, cardiovascular, device-related, and hospital-acquired infections. This review describes the most recent evidence of the pathogenic potential of S. aureus, which is commonly part of the human microbiota but can lead to severe infections. The prevalence of pathogenic S. aureus in hospital and community settings contributes to substantial morbidity and mortality, particularly in individuals with compromised immune systems. The immunopathogenesis of S. aureus infections involves intricate interactions with the host immune and non-immune cells, characterized by various virulence factors that facilitate adherence, invasion, and evasion of the host's defenses. This review highlights the complexity of S. aureus infections, ranging from mild to life-threatening conditions, and underscores the growing public health concern posed by multidrug-resistant strains, including methicillin-resistant S. aureus (MRSA). This article aims to provide an updated perspective on S. aureus-related infections, highlighting the main diseases linked to this pathogen, how the different cell types, virulence factors, and signaling molecules are involved in the immunopathogenesis, and the future perspectives to overcome the current challenges to treat the affected individuals.

Pseudo-ternary phase diagram based PEGylated nano-dispersion of linezolid to promote wound regeneration: an in vitro and in vivo evaluation

Open wounds are prone to bacterial infiltration mostly resistant strains like methicillin-resistant Staphylococcus aureus (MRSA), which affects healing of open wounds. Topical linezolid nano-dispersion using essential oils as nanoemulgel can increase solubility of drug and bypass side-effects like GI-irritation of oral administration. Pseudo-ternary phase diagram was built to optimise nanoemulsion. Surfactant/co-surfactant mixture (3:1), deionised water and Oilmix (4:1) with drug were vortexed and then ultrasonicated. 1% carbopol gel of optimised nanoemulsion was prepared and characterised, exposed to antimicrobial study, cytocompatibility study using HEK293 cell-line, and in vivo wound healing study using rat excision model. Histological study was performed to confirm growth of stratum corneum. Optimised formulation has particle size (244.6 ± 178.66 nm), polydispersity index (25%), entrapment efficiency (92.3 ± 3.38%) and in vitro drug release (87.58 ± 4.16%) best fitted in Korsmeyer-Peppas kinetics model. Nanoemulgel F6 (0.2%w/w) was found with viscosity of 5345 ± 6 cP constituting a very excellent antimicrobial effect against MRSA. HEK293 cells had shown good cytocompatibility with formulation. The wound contraction rate was 99.66 ± 0.57% at day 15 on daily application of nanoemulgel and stratum corneum was almost fully regenerated. The developed nanoemulgel has potential antimicrobial efficacy and can promote wound healing.

Impeding Biofilm-Forming Mediated Methicillin-Resistant Staphylococcus aureus and Virulence Genes Using a Biosynthesized Silver Nanoparticles-Antibiotic Combination

Methicillin-resistant Staphylococcus aureus (MRSA) continues to represent a significant clinical challenge, characterized by consistently elevated rates of morbidity and mortality. Care regimen success is still difficult and necessitates assessing new antibiotics as well as supplemental services, including source control and searching for alternative approaches to combating it. Hence, we propose to synthesize silver nanoparticles (Ag-NPs) by employing a cell-free filter (CFF) of Streptomyces sp. to augment antibiotic activity and combat biofilm-forming MRSA. Seven bacterial isolates from clinical samples were identified, antibiotics were profiled with Vitek-2, and the phenotypic detecting of biofilm with Congo red medium and microplate assay was carried out. The PCR technique was used for detecting genes (icaA and icaD) coded in biofilm forming. The characterization of Ag-NPs was performed using several analytical methods, such as UV spectroscopy, dynamic light scattering (DLS), zeta potential measurement, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The antibacterial properties of Ag-NPs and oxacillin-Ag-NPs were assessed against standard strains and clinical isolates by employing the agar well diffusion technique and the microdilution assay. The biogenic synthesis Ag-NPs resulted in uniformly spherical particles, with an average size of 20 nm. These Ag-NPs demonstrated significant activity against biofilm-forming MRSA, with minimum inhibitory concentrations (MICs) ranging from 12 to 15 μg/mL. Additionally, Ag-NPs completely impede biofilm formation by MRSA at sublethal doses of 0.75 MICs. The expression levels of the icaA and icaD genes were reduced by 1.9- to 2.2- and 2.4- to 2.8-fold, respectively. A significant synergistic effect was noted when Ag-NPs were used in combination with oxacillin, leading to reduced MICs of 1.87 μg/mL for oxacillin and 4.0 μg/mL for Ag-NPs against MRSA. The FICi of 0.375 further validated the synergistic relationship between oxacillin and Ag-NPs at the concentrations of 1.87 and 4 μg/mL. Findings from the time-kill test demonstrated the highest reduction in log10 (CFU)/mL of the initial MRSA inoculum after 12-hour exposure. The cytotoxicity analysis of Ag-NPs revealed no significant cytotoxic effects on the human skin cell line HFB-4 at low concentrations, with IC50 values of 61.40 µg/mL for HFB-4 and 34.2 µg/mL for HepG-2. Comparable with oxacillin-Ag-NPs, Ag-NPs showed no cytotoxic effects on HFB-4 at different concentrations and exhibited an IC50 value of 31.2 against HepG-2-cells. In conclusion, the biosynthesis of Ag-NPs has demonstrated effective antibacterial activity against MRSA and has completely hindered biofilm formation, suggesting a valuable alternative for clinical applications.

Graveyard effects of antimicrobial nanostructured titanium over prolonged exposure to drug resistant bacteria and fungi

Innovations in nanostructured surfaces have found a practical place in the medical area with use in implant materials for post-operative infection prevention. These textured surfaces should be dual purpose: (1) bactericidal on contact and (2) resistant to biofilm formation over prolonged periods. Here, hydrothermally etched titanium surfaces were tested against two highly antimicrobial resistant microbial species, methicillin-resistant Staphylococcus aureus and Candida albicans. Two surface types - unmodified titanium and nanostructured titanium - were incubated in a suspension of each microbial strain for 1 day and 7 days. Surface topography and cross-sectional information of the microbial cells adhered to the surfaces, along with biomass volume and live/dead rate, showed that while nanostructured titanium was able to kill microbes after 1 day of exposure, after 7 days, the rate of death becomes negligible when compared to the unmodified titanium. This suggests that as biofilms mature on a nanostructured surface, the cells that have lysed conceal the nanostructures and prime the surface for planktonic cells to adhere, decreasing the possibility of structure-induced lysis. Synchrotron macro-attenuated total reflection Fourier transform infrared (macro ATR-FTIR) micro-spectroscopy was used to elucidate the biochemical changes occurring following exposure to differing surface texture and incubation duration, providing further understanding into the effects of surface morphology on the biochemical molecules (lipids, proteins and polysaccharides) in an evolving and growing microbial colony.

Controlling Multidrug-Resistant Staphylococcus aureus by Combined Use of Antimicrobials and Phage STPX-6 with Broad Spectrum and High Efficiency

Objective: The emergence of antibiotic-resistant Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), poses a great challenge for animal and public health. This study aimed to isolate a broad-spectrum and high-efficiency MRSA phage and explore the phage-antibiotic synergistic effect on MRSA. Results: Phage STPX-6 belongs to Caudovirales, Podoviridae. It has a hexahedral head and a short tail. Its genome length was 17,007 bp, and it did not contain resistance genes and virulence genes. STPX-6 lysed 79.6% (133/167) of 167 S. aureus and 87.96% (95/108) of MRSA from different sources. The titer of phage was 1.18 × 1010 PFU/mL, the optimal multiplicity of infection was 1, the latent period and lysis period were about 10 min and 60 min, respectively, and the burst amount was 68 PFU/cell. At 50°C and 70-90°C, the titer of STPX-6 was maintained at about 1010 PFU/mL and at least 103 PFU/mL, respectively. In the range of pH 4-12, the titer of phage remained above 108 PFU/mL, and it remained above 104 PFU/mL at pH 2, 3, 13, and 14. The combined application of phage STPX-6 and enrofloxacin, doxycycline, ampicillin could reduce the minimum inhibitory concentration (MIC) of the three antibiotics to 1/4 MIC, 1/16 MIC, and 1/2 MIC, respectively. Conclusion: This study found that for the host MRSA, lytic phage STPX-6 had the characteristics of a broad lytic spectrum, a short latent period, strong adaptability and strong tolerance to high temperature, a strong acid and strong alkali environment, and might maintain certain activity under extreme environment. More importantly, the combination of phage STPX-6 with enrofloxacin, doxycycline, and ampicillin could reduce the antibiotic concentration used for MRSA. In other words, phages as new antibacterial agents have received increasing attention. The combined application of phages and antibiotics provides a new method for controlling multidrug resistant bacteria and reduce the use of antibiotics.

Antimicrobial Potential of Cannabinoids: A Scoping Review of the Past 5 Years

In the scenario of fighting bacterial resistance to antibiotics, natural products have been extensively investigated for their potential antibacterial activities. Among these, cannabinoids-bioactive compounds derived from cannabis-have garnered attention for their diverse biological activities, including anxiolytic, anti-inflammatory, analgesic, antioxidant, and neuroprotective properties. Emerging evidence suggests that cannabinoids may also possess significant antimicrobial properties, with potential applications in enhancing the efficacy of conventional antimicrobial agents. Therefore, this review examines evidence from the past five years on the antimicrobial properties of cannabinoids, focusing on underlying mechanisms such as microbial membrane disruption, immune response modulation, and interference with microbial virulence factors. In addition, their synergistic potential, when used alongside standard therapies, underscores their promise as a novel strategy to address drug resistance, although further research and clinical trials are needed to validate their therapeutic use. Overall, cannabinoids offer a promising avenue for the development of innovative treatments to combat drug-resistant infections and reduce the reliance on traditional antimicrobial agents.

Multi-target anti-MRSA mechanism and antibiotic synergistic effect of marine alkaloid Ascomylactam A in vitro and in vivo against clinical MRSA strains

Methicillin-resistant Staphylococcus aureus (MRSA), as a kind of multi-drug resistant bacteria, often causes serious sanitary infection problems. Marine fungi are seen as a promising source of lead compounds for antibiotics. In this research, the antibacterial activity, antibiotic synergistic effect and mechanism of the alkaloid Ascomylactam A (AsA) derived from the marine fungus Microascus sp. SCSIO 41821 were investigated in vivo and in vitro. Antibacterial assays showed that AsA had excellent antibacterial activity and inhibition of biofilm formation against MRSA SC41993, and exhibitted synergistic antibacterial effects with clinical antibiotics. Transcriptomics revealed the potential mechanism that AsA affected the formation of MRSA biofilm, cell wall synthesis and virulence through LytSR, VraSR, ArgAC and KdpDE two-component system (TCS). In addition, by treatment with AsA, it was found that AdhE protein was a potential target for oxidative stress and lipid peroxidation in MRSA, and the resistance of MRSA was reversed by regulating some genes. In vivo experiments showed that AsA combined with gentamicin sulfate (GMS) had a better therapeutic effect than alone against clinical MRSA USA300, especially in the heart. In this study, the antibacterial mechanism of decahydrofluorene-class alkaloids was preliminarily investigated, supporting the potence of AsA as a promising therapeutic agent to combat MASA infections.

Topical antimicrobial formulations using medicinal plant-derived essential oils targeting methicillin resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) causes a variety of healthcare-associated and community-acquired infections. Due to limited availability of effective antimicrobials for treating MRSA infections, there is a growing need to explore alternative therapeutic approaches. Here, the antimicrobial activities of 19 oils, popularly used for their medicinal properties, were tested against MRSA USA300. Oils obtained from cinnamon, clove, tangerine, and coriander showed the most promising activities, demonstrating bactericidal, anti-adhesive and anti-biofilm activities, and synergistic properties with common antibiotics. Given that clove and cinnamon oils showed the best activities, they were incorporated into topical formulations. Not only did the formulations with oils maintain antimicrobial and anti-adhesive activities, but their anti-biofilm property was potentiated. Tests on Galleria mellonella larvae suggested that the formulation is non-toxic. The formulations proposed here are a great alternative for the decolonisation of surfaces containing MRSA and can help circumventing antimicrobial resistance, a growing threat in the hospital environment.

Therapeutic potential of isoallolithocholic acid in methicillin-resistant Staphylococcus Aureus peritoneal infection

A significant increase in multidrug-resistant Methicillin-resistant Staphylococcus aureus (MRSA) infections has made it crucial to explore new antimicrobial drugs and strategies. Emerging evidence suggests that the bile acid metabolite isoallolithocholic acid (isoallo-LCA) may contribute to reducing the risk of infection among centenarians. However, its precise role remains somewhat ambiguous and necessitates further investigation. This study aims to investigate the roles of isoallo-LCA in MRSA-associated peritoneal infection. The effects of isoallo-LCA on peritoneal infection are examined in a MRSA-induced peritoneal infected model. Antibacterial activity, biofilm formation assay, and bacterial membrane permeability experiments are conducted to explore the mechanisms involved. Our findings demonstrate that isoallo-LCA effectively suppresses the replication of MRSA with minimal adverse effects on mammalian cells. Furthermore, isoallo-LCA significantly inhibits the formation of bacterial biofilms and eradicates existing bacterial biofilms of MRSA. Administration of isoallo-LCA reduces MRSA colonization in peritoneal organs and alleviates peritonitis-related inflammation and damage in a MRSA-infected peritonitis mice. Mechanistically, isoallo-LCA exhibits potent bactericidal activity against MRSA by disrupting the integrity and permeability of bacterial cells. In addition, isoallo-LCA also enhances the macrophage phagocytosis. In conclusion, our results suggest that isoallo-LCA could be an effective treatment for infections caused by MRSA.

Chemical composition, antibacterial and antioxidant activities of Piper betle and Anethum graveolens essential oils against Methicillin-resistant Staphylococcus aureus clinical isolates

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infection worldwide due to its antimicrobial resistance. Plant-derived essential oils (EOs) have undergone extensive observational and clinical research to explore their antimicrobial properties. The present study aimed to check mec A positive MRSA isolates using sequencing analysis, determination of chemical composition using gas chromatography-mass spectroscopy (GC-MS), antioxidant, and antimicrobial activity of Anethum graveolens and Piper betle EOs against the infectious agent MRSA. The result demonstrates a significant antibacterial activity of both essential oils against MRSA clinical isolates. GC-MS analysis of Piper betle showed (41.06%) 3-Allyl-6-methoxyphenol (Eugenol) as the major compound, whereas Anethum graveolens exhibited o-cymene (14.01%) abundantly. Piper betle essential oil retained appreciable levels of total phenolic (39.5 ± 10.9 mg/g of gallic acid equivalents) and flavonoid content (216 ± 145 mg quercetin equivalent/g), when compared to Anethum graveolens essential oil. A strong correlation was observed between antioxidant activity (DPPH, FRAP, and ABTS), total phenolic, and total flavonoid content in the Piper betle and displayed using principal component analysis (PCA) and a scatter matrix plot. Parallelly, clear morphological bacterial alterations were visualized by scanning electron microscopy after treating it with essential oils. MRSA showed malformed cell surfaces or broken cells with pore formation and septae. These findings imply that both essential oils are potential natural sources of antimicrobials against the MRSA superbug. They can also be used in combination therapies with other plant EOs or with traditional antibiotics to combat the rise of bacteria resistance.

Urtica dioica Aqueous Leaf Extract: Chemical Composition and In Vitro Evaluation of Biological Activities

Urtica dioica L. has been used as a natural remedy due to its healing properties for over 2000 years. The aim of this study is to investigate the chemical composition, antimicrobial, antioxidant, and antitumor properties in vitro of the aqueous extract of Urtica dioica leaves (AEUD). The chemical composition was assessed by an ultra-high-performance liquid chromatography system coupled to a benchtop QExactive high-resolution accurate mass spectrometry operating in a data-dependent acquisition mode as a non-target approach. Minimal inhibitory concentration (MIC) and disc diffusion were used to assess the antibacterial efficacy against nine bacterial strains. The antioxidant impact was assessed using DPPH, ABTS, FRAP, and ferrous ion-chelating ability assays. By using the MTT method, the cytotoxicity effect of AEUD on colon cancer cell HCT-116 was evaluated. Flow cytometry was used to analyze the cell cycle. Finally, the anti-migration and anti-invasion properties of AEUD on HCT-116 cells were estimated using the wound healing test and Transwell assays. AEUD is a rich source of phenolic compounds. The results of disc diffusion and MIC showed that the AEUD is more active against Gram-positive bacteria than against Gram-negative bacteria. MTT assay confirmed that the AEUD inhibited HCT-116 colon cancer cell proliferation. Findings of flow cytometry confirmed that cell cycle arrest occurred at the G2 phase. Additionally, AEUD had anti-migration and anti-invasion effects. This study shows that Urtica dioica aqueous leaf extract exhibits potential antibacterial, antioxidant, and antitumoral activities on HCT-116 colon cancer cells.

Changing dynamics of bloodstream infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium in Germany, 2017-2023: a continued burden of disease approach

BACKGROUND

Antimicrobial resistance is a global threat to public health, with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREfm) being major contributors. Despite their clinical impact, comprehensive assessments of changes of the burden of bloodstream infections in terms of Disability-Adjusted Life Years (DALYs) and attributable deaths over time are lacking, particularly in Germany.

METHODS

We used data from the Antimicrobial Resistance Surveillance system, which covered about 30% of German hospitals. Bloodstream infections were defined by a VREfm or MRSA-positive blood culture. We estimated incidences as a first step to further use these rates to calculate DALYs and attributable deaths using the Burden of Communicable Disease in Europe toolkit. The analysis included stratification by age, sex and region.

RESULTS

From 2017 to 2023, 6262 MRSA and 5442 VREfm blood culture-positive isolates were identified. The incidence of MRSA bloodstream infections decreased from 4.0 to 2.1 per 100,000 population, with estimated DALYs decreasing from 14.6 to 8.6 per 100,000 and attributable deaths from 591 to 316. Conversely, VREfm-BSI incidence doubled from 1.7 to a peak of 3.0 (2021) before declining back to 1.7 per 100,000 in 2023, with estimated DALYs increasing from 8.9 to 16.5 and then decreasing to 8.5 per 100,000 and attributable deaths increasing from 317 to 327. Men and people over 60 years had the highest burden, with noticeable regional differences.

CONCLUSION

MRSA and VREfm bloodstream infections followed different trends in the past and now present a comparable burden in Germany. Both pathogens pose a significant threat, particularly to hospitalised older aged men. Our findings highlight the need for targeted prevention and continued surveillance of MRSA and VREfm to reduce infections and their impact.

From Farm to Community: Dispersal of Potentially Pathogenic Staphylococcus and Mammaliicoccus Species and Antimicrobial Resistance Across Shared Environments

Staphylococcaceae are a diverse bacterial family with important implications for human and animal health. This study highlights the One Health relevance of their environmental dispersal, particularly, by identifying closely related or genetically identical strains circulating between farm and community environments. Environmental Staphylococcaceae strains were isolated from animal farms and interconnected areas within a university setting, both influenced by anthropogenic activities. Genetic diversity analysis via GTG5-PCR revealed that specific strains circulated across these environments, likely facilitated by human interaction, supporting the potential for cross-environmental bacterial transfer. The strains were further tested for antimicrobial resistance against a panel of antibiotics, biofilm formation, and the presence of resistance-associated genes. We identified a wide array of Staphylococcaceae species (n = 16), with over half being pathogenic to humans and animals, including S. aureus, S. epidermidis, S. haemolyticus, and S. saprophyticus. Notably, 55.5% of the strains exhibited multidrug resistance, and 15.9% harbored the methicillin resistance gene mecA, underscoring the challenges these infections might pose to treatment. Biofilm-forming capabilities further enhance the environmental persistence of these strains. These findings underscore the critical need for surveillance and targeted intervention strategies in a One Health framework to mitigate antimicrobial resistance across shared environments.

Antarmycins: Discovery, Biosynthesis, Anti-pathogenic Bacterial Activity, and Mechanism of Action from Deep-Sea-Derived Pseudonocardia antarctica

The rapid emergence of antimicrobial-resistant pathogenic microbes has accelerated the search for novel therapeutic agents. Here we report the discovery of antarmycin A (1), an antibiotic containing a symmetric 16-membered macrodiolide core with two pendant vancosamine moieties, one of which is glucosylated, from deep-sea-derived Pseudonocardia antarctica SCSIO 07407. The biosynthetic gene cluster of 1 was identified on a giant plasmid featuring transferable elements. In-depth biosynthetic investigation enabled us to (i) identify a set of seven genes associated with the product of the vancosamine moiety; (ii) discover two glycosyltransferases dedicated to the transfer of pendant sugars; and (iii) isolate rhamnose-modified antarmycin B (2) and a deglucosylated derivative antarmycin C (3) from genetically engineered mutant strains. Antibacterial assays revealed that 1 displays superior antibacterial properties with potent in vitro activities against the critical priority pathogens, multidrug-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus, fast bacterial killing, insusceptibility to antimicrobial resistance, and high in vivo efficiency in infection models. Mechanistic investigations revealed that 1 disrupts the bacterial cell membrane through a mechanism involving interactions between the vancosamine moieties and membrane-embedded phosphatidylglycerol/phosphatidylethanolamine. The results provide insights into the biological generation of vancosamine in natural products and demonstrate the potential of 1 as an effective lead to address the growing antimicrobial resistance threats.

Infective endocarditis: a growing threat despite medical progress. A look at trends in Spain

INTRODUCTION AND OBJECTIVES

Infective endocarditis (IE) is a serious public health problem both in Spain and worldwide. This study aimed to analyze the trends in the incidence of IE in Spain from 1992 to 2021.

METHODS

We used IE incidence data from the Global Health Data Exchange and population data from the Spanish National Statistics Institute to analyze changes in age-standardized incidence rates. Joinpoint and Age-Period-Cohort (A-P-C) models were applied to identify significant trend changes and the effects of age, period, and birth cohort.

RESULTS

The age-standardized incidence rates of IE increased from 17.5 cases per 100 000 population in 1992 to 30.8 per 100,000 in 2021 among men and from 16.8 per 100 000 in 1992 to 22.9 per 100 000 in 2021 among women. Joinpoint analysis revealed distinct trend changes, with men having a faster rate of increase (1.9%) compared with women (1.1%). The male-to-female incidence rate ratio peaked at 1.4, indicating a higher risk of IE among men. The incidence of IE was significantly influenced by age, period, and cohort. Both sexes showed increasing risk with age. Risk increased in women born in the late 20th and early 21st centuries compared with earlier cohorts. Men in these later cohorts showed a decreasing risk. Period effects increased from the 1990s to the mid-2000s and then declined, especially among men.

CONCLUSIONS

This study reveals a significant increase in the incidence of IE in Spain, especially among older adults and men. These trends reflect demographic changes, medical advances, and changing risk factors.

Prevalence of Methicillin-Resistant Staphylococcus aureus in Livestock in Japan: A Systematic Review and Meta-Analysis

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an important health issue that is estimated to have caused 130,000 deaths worldwide in 2021. As more instances of cross-species transmission of MRSA have been reported, concerns have been raised regarding the spread of livestock-associated MRSA to humans. The prevalence of MRSA in livestock varies globally. This study systematically reviews the prevalence of MRSA at the farm and animal levels in Japan. Methods: Relevant studies published in English or Japanese between 2000 and 2023 were retrieved from four databases. Pooled prevalences at the farm and animal levels in Japanese farms were calculated using a random-effects model. Subgroup and meta-regression analyses were also performed to explore sources of heterogeneity. Results: The 13 studies included in this meta-analysis yielded an MRSA prevalence of 3.54% (95% confidence interval [CI] 0.65-8.30%) at the individual pig level, 13.07% (95% CI 5.42-23.04%) at the pig farm level, 0.0% (95% CI 0.00-0.04%) at the individual cattle level, and 0% (95% CI 0.00-0.44%) at the individual chicken level. A significant increase in MRSA prevalence over time was evident at the individual pig level by both subgroup analysis (p = 0.020) and meta-regression (p = 0.019). Conclusions: Our results indicated that the proportion of pigs that can be a source of MRSA infection in humans has been steadily increasing in Japan. Despite some limitations, our findings strongly imply a need for more attention to pig-to-human MRSA transmission in Japan.

Whole-genome analysis of a ST45-SCCmec IVa (2B)-t116 methicillin-resistant Staphylococcus aureus strain isolated from the sputum of a 5-year-old child with pneumonia

Introduction

Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 is a major global MRSA lineage with huge strain diversity and a high clinical impact. In Hainan and Guangzhou of China, the ST45-MRSA was mainly associated with t116.

Methods

The MRSA strain SA2107 was isolated from the sputum of a 5-year-old child with pneumonia. The whole genome of SA2107 was sequence using Illumina (Novaseq 6000) and PacBio (Sequel IIe) sequencers, and the sequences were assembled using hybrid assembly. The carriage of antibiotic resistance genes, virulence genes, and mobile genetic elements were identified using bioinformatics tools. The comparative genomic analyses of MRSA strain SA2107 with other MRSA strains worldwide were performed.

Findings

The genome size of ST45-SCCmec IVa (2B)-t116 MRSA strain SA2107 was ~2.9 Mb. Mobile genetic elements analysis of SA2107 revealed two plasmids (30,064-bp pSA2107-1 and 8,033-bp pSA2107-2), three prophages, two integrative and conjugative elements (ICEs), and two insertion sequences (ISs, IS431 and IS1272). The SCCmec IVa (2B) carried by SA2107 contained the class B mec gene complex (IS431-mecA-ΔmecR1-IS1272) and type 2 ccr gene complex (ccrA2 and ccrB2). Besides mecA, another beta-lactam resistance gene blaZ was found to located on six copies of bla complex (blaZ, blaR1, and blaI) on the chromosome of SA2107. Three kinds of virulence factors were detected on the chromosome of SA2107, including genes encoding toxins, exoenzyme, and immune-modulating protein. Notably, the three prophages harbored by the chromosome of SA2107 all carried virulence genes.

Conclusion

Thus far, only three complete genomes available for ST45-SCCmec IVa (2B)-t116 strain from United States, Germany, and Australia, respectively. The strain SA2107 was the first complete genome data (CP104559) from China for ST45-SCCmec IVa (2B)-t116 MRSA.

Strategies for Survival of Staphylococcus aureus in Host Cells

Staphylococcus aureus, a common pathogen, is capable of producing a significant array of toxins and can develop biofilms or small colony variants (SCVs) to evade detection by the immune system and resist the effects of antibiotics. Its ability to persist for extended periods within host cells has led to increased research interest. This review examines the process of internalization of S. aureus, highlighting the impact of its toxins and adhesion factors on host cells. It elucidates the intricate interactions between them and the host cellular environment, thereby offering potential strategies for the treatment and prevention of S. aureus infections.

Microwave-Assisted Synthesized ZnO@APTES Quantum Dots Exhibits Potent Antibacterial Efficacy Against Methicillin-Resistant Staphylococcus aureus Without Inducing Resistance

Background

Antibiotic resistance of many bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), has become a major threat to global health. Zinc Oxide Quantum dots (ZnO-QDs) show good antibacterial activity, but most of them are insoluble in water, limiting their application range, and there is a lack of research on drug resistance inducement.

Methods

The water-soluble zinc oxide quantum dots modified by APTES (ZnO@APTES QDs) were prepared by a microwave assisted synthesis. Then ZnO@APTES QDs were characterized through various methods. After confirmation of synthesized ZnO@APTES QDs, its bactericidal effect on MRSA was detected through in vitro and in vivo experiments, and its mechanism of action was analyzed.

Results

Characterization analysis revealed that the ZnO@APTES QDs have a particle size of 5 nm. The minimum inhibitory concentrations (MIC) were determined to be 64 µg mL-1 for Escherichia coli (E. coli) and 32 µg mL-1 for MRSA. The ZnO@APTES QDs showed significant inhibition of MRSA biofilm formation and effectively disrupted mature biofilms. Notably, the ZnO@APTES QDs did not induce tolerance or resistance even after 30 days of repeated exposure, whereas antibiotics led to a rise in bacterial MIC within 3 days and a 60-fold increase after 30 days. Mechanistic analysis indicated that the positively charged quantum dots interact with bacterial surfaces, altering membrane fluidity. Once inside the bacteria, the ZnO@APTES QDs generate reactive oxygen species (ROS), causing DNA damage and bacterial cell death. Moreover, the ZnO@APTES QDs possessed good biocompatibility and demonstrated significant therapeutic efficacy against drug-resistant bacterial infections in both macrophage and mouse wound infection models.

Conclusion

In summary, we have synthesized a highly effective water-soluble ZnO@APTES QDs that shows strong antibacterial and therapeutic efficacy against MRSA and other bacteria. The ZnO@APTES QDs holds significant potential for development as a new treatment agent for combating antibiotic-resistant infections.

How Will Nanomedicine Revolutionize Future Dentistry and Periodontal Therapy?

Periodontitis is a prevalent inflammatory disease affecting the supporting structures of the teeth, leading to gum recession, tooth loss, and systemic health complications. Traditional diagnostic methods and treatments, such as clinical evaluation and scaling, often fall short in early detection and targeted therapy, particularly in complex or advanced cases. Recent advancements in nanomedicine offer promising solutions for improving both the diagnosis and treatment of periodontitis. Nanoparticles, such as liposomes, quantum dots, and nanorods, have demonstrated potential in enhancing diagnostic accuracy by enabling more precise detection of periodontal pathogens and biomarkers at the molecular level. Furthermore, nanotechnology-based therapies, including drug delivery systems and antimicrobial agents, offer localized and controlled release of therapeutic agents, enhancing efficacy and reducing side effects compared to conventional treatments. This study reviews the current applications of nanomedicine in the diagnosis and treatment of periodontitis, highlighting its potential to revolutionize periodontal care by improving early detection, reducing treatment times, and enhancing therapeutic outcomes.

Study on Time Distribution and Pathogenic Bacteria of Infection After Auricular Reconstruction With Tissue Expansion for Microtia

BACKGROUND

Postoperative infection is one of the main complications that affect the surgical effect of auricular reconstruction with tissue expansion. Understanding the susceptible time and distribution of pathogens is especially important for the treatment.

METHOD

The data of patients with infection after auricular reconstruction with tissue expansion from September 1, 2018 to August 30, 2024 were collected retrospectively. The microbe species identification results, diagnosis time of infection, surgical methods, and kinds of pathogenic bacteria were analyzed. Statistical methods were used to analyze and calculate the difference in infection time and the distribution of pathogenic bacteria.

RESULT

From September 1, 2018 to August 30, 2024, 237 cases of infection after auricle reconstruction with tissue expansion were diagnosed, and 252 strains of 18 kinds of pathogenic bacteria were detected. Among them, S. aureus (85 strains, 33.73%) and S. epidermidis (40 strains, 15.87%) were the 2 main pathogens. Postoperative infection mainly occurred in the first stage (72 cases, 30.38%) and the second stage (98 cases, 41.35%). The MRSA infection rate in the second stage (24.46%) was significantly higher than that in the other stages. The infection rate was significantly higher in winter (from November to January) (P<0.05). There was no significant difference among other seasons (P>0.05).

CONCLUSION

The main pathogen of infection after ear reconstruction with tissue expansion is Staphylococcus aureus, and winter is the peak period of infection. There are some differences in infection rate and distribution of pathogenic bacteria in different stages of surgery.