Total Face Reconstruction with Flap Prefabrication and Soft-Tissue Expansion Techniques.

SUMMARY: Total facial deformities always lead to psychological and functional consequences, making plastic and reconstructive surgery a great challenge. The skin of the anterior chest area is matched in thickness, texture, and color to the head and face. The purpose of this article was to discuss and evaluate reconstructive surgeons' experiences with obtaining a monoblock flap from the anterior thoracic area for entire face reconstruction using flap prefabrication, soft-tissue expansion, and facial plastic surgery following skin flap transplantation. Two patients underwent prefabricated expanded anterior thoracic flap reconstructions for total facial deformities; data collection included face defect size, flap type, the shape of the expander, expansion time, and complications. All the face flaps that were transplanted survived without major complications. It is concluded that using a prefabricated expanded flap to reconstruct an entire facial soft-tissue defect can provide a high degree of matching, a wide enough covering area, and a thin enough skin thickness to cover the face. Autologous flap grafting is easy to implement and has a high application value.

Azomycin Orchestrate Colistin-Resistant Enterobacter cloacae Complex's Colistin Resistance Reversal In Vitro and In Vivo.

The Enterobacter cloacae complex (ECC) is a group of nosocomial pathogens that pose a challenge in clinical treatment due to its intrinsic resistance and the ability to rapidly acquire resistance. Colistin was reconsidered as a last-resort antibiotic for combating multidrug-resistant ECC. However, the persistent emergence of colistin-resistant (COL-R) pathogens impedes its clinical efficacy, and novel treatment options are urgently needed. We propose that azomycin, in combination with colistin, restores the susceptibility of COL-R ECC to colistin in vivo and in vitro. Results from the checkerboard susceptibility, time-killing, and live/dead bacterial cell viability tests showed strong synergistic antibacterial activity in vitro. Animal infection models suggested that azomycin-colistin enhanced the survival rate of infected Galleria mellonella and reduced the bacterial load in the thighs of infected mice, highlighting its superior in vivo synergistic antibacterial activity. Crystal violet staining and scanning electron microscopy unveiled the in vitro synergistic antibiofilm effects of azomycin-colistin. The safety of azomycin and azomycin-colistin at experimental concentrations was confirmed through cytotoxicity tests and an erythrocyte hemolysis test. Azomycin-colistin stimulated the production of reactive oxygen species in COL-R ECC and inhibited the PhoPQ two-component system to combat bacterial growth. Thus, azomycin is feasible as a colistin adjuvant against COL-R ECC infection.

Radiographic Study of the Nasal Valve in Different CT Evaluation Method in Asian Patients with Unilateral Cleft Lip Nose.

OBJECTIVE(S): It was the first study to apply and compare two CT methods to assess the validity and clinical significance of structural alterations of the nasal valve in patients with cleft lip nose for assessing nasal ventilation disturbance. METHODS: The study collected data from the NOSE score, as well as internal nasal valve area, internal nasal valve angle, external nasal valve area, and septal deviation angle, to evaluate the differences and correlations between those factors in patients with cleft lip and nose. RESULTS: There were significant differences among INV transverse and coronal area and INV angle on different axial standardized planes between clefted side and non-clefted side. There were statistically significant negative correlations between NOSE scores and those indicators of standard plane and acoustic-axis standardized coronal plane. NOSE score and NSD angle were the indicators of significant differences in the measured data of different complications groups (p = 0.002, p = 0.017). The correlation comparison showed that two standardized CT imaging transverse planes have similar correlations in NOSE score, NSD angle, and complications. CONCLUSION: The results of the two CT evaluation methods showed that there was a significant difference in nasal valve area on the cleft and non-cleft sides, which was significantly associated with nasal ventilation disturbance. The CT evaluation method based on standard axial 3D reconstruction is more convenient to use in the clinic, can be used for pre-surgical evaluation of nasal repair in patients with secondary nasal deformities of unilateral cleft lip, and is valuable for treatment. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A New Algorithm for Secondary Repair of Unilateral Cleft Lip Nasal Deformity.

OBJECTIVES: Following primary surgery for unilateral cleft lip palate (UCLP), cleft lip nasal deformities (CLNDs) (nasal asymmetry, collapsed nasal alae, and a widened alar base) are generally inevitable and often require secondary rhinoplasty. However, reconstructing a cleft nose with an alar tissue deficiency remains challenging for rhinoplasty surgeons. METHODS: The manifestations of common deformities are described herein, and a secondary rhinoplasty technique for unilateral CLNDs using a nasolabial flap (NLF) has been proposed for patients with alar tissue deficiency. Secondary rhinoplasties were performed in 12 patients with unilateral CLNDs between 2020 and 2021 using a NLF. Photogrammetric measurements were performed preoperatively and postoperatively. A total of 12 flaps were successfully transferred. Ten patients were followed up for >1 year. RESULTS: Significant postoperative decreases in nasal alar width were measured in both the base view (p < 0.050) and the frontal view (p < 0.050). Despite the additional facial scars that occurred in some cases, all patients were satisfied with the aesthetic effects. CONCLUSIONS: The NLF achieved satisfactory results in secondary rhinoplasty of unilateral CLND for patients with nasal tissue deficiencies in whom the surgeon weighed the potential benefits over postoperative scarring. LEVEL OF EVIDENCE: 4 Laryngoscope, 2023.

A New Classification of Pollybeak Deformity and Its Treatment in Asian Rhinoplasty.

BACKGROUND: Supratip deformity, also known as pollybeak deformity, is a common complication of primary and secondary rhinoplasty, characterized by fullness in the supratip region. The correction of pollybeak deformity is a challenging procedure, and its management requires a thorough understanding of the pathogenic mechanism of pollybeak deformity. OBJECTIVES: This study aimed to evaluate the effectiveness of surgical methods for correcting pollybeak deformity in Asian rhinoplasty. METHODS: A retrospective chart review was conducted for 53 patients who underwent pollybeak correction between 2021 and 2022. A modified classification system for pollybeak deformity, the Supratip Fullness Rating Scale (SFRS), was developed to evaluate supratip fullness. The aesthetic outcomes of the patients were assessed by surgeons using the visual analog scale (VAS), and patient was self-assessed using the Rhinoplasty Outcome Evaluation (ROE) scale. RESULTS: The study demonstrated that our surgical method resulted in satisfactory outcomes, with a mean SFRS score change from 2.34[0.65] to 0.23[0.42], a decrease in VAS score from 7.47[1.73] to 1.79[1.67] and a high satisfaction rate of 77.36%, calculated by ROE score. No complications were reported. CONCLUSION: Our surgical method for correcting pollybeak deformity in Asian rhinoplasty can result in satisfactory outcomes, particularly in terms of aesthetic appearance, without any side effects. The use of the modified classification system (SFRS) can provide an objective evaluation of supratip fullness, thereby aiding in the management of this challenging complication. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Retrospective Study on the Reconstruction of Nasal Septal Mucosal Defects after Asian Rhinoplasty.

BACKGROUND: Nasal septal mucosal defects following rhinoplasty in Asian patients are uncommon complications. However, the reconstruction of such defects presents a challenging task in plastic surgery. The aim of this study was to present comprehensive surgical strategies for the reconstruction of nasal septal mucosal defect after rhinoplasty. METHODS: Thirteen cases presenting with nasal septal mucosal defects between January 2016 and October 2021 were retrospectively reviewed. The size, location, and severity of the defect as well as the extent of cartilage exposure were taken into consideration during evaluation, and surgical approaches were employed for repair accordingly. Patient satisfaction was evaluated using a questionnaire with visual analog scale (VAS) and nasal obstruction symptom evaluation scale (NOSE). RESULTS: The average postoperative follow-up period in this study group was 10.15 months. Reconstruction of nasal septal mucosal defects resulted in successful treatment for all patients. There was no evidence of flap failure or nasal valve stenosis. All patients were satisfied with the reconstruction outcome. CONCLUSIONS: The successful application of surgical techniques for nasal septal mucosal defects after rhinoplasty requires comprehensive consideration. The utilization of the retrograde-flow superior labial artery mucosal flap appears to be a secure, efficient, and effective technique for nasal septal mucosal defect reconstruction in rhinoplasty, particularly in cases with cartilage exposure. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

New classification system of contracted nose and its treatment algorithm.

BACKGROUND: The nasal contracture after rhinoplasty is one of the most severe complications in East Asian patients. The classification and treatment algorithm of nasal contracture have not yet been established. This study aimed to develop a new classification system and treatment algorithm of contracted noses in East Asian patients to improve treatment outcomes. METHODS: A retrospective study was conducted with 62 patients with nasal contracture who underwent a revision rhinoplasty between March 2017 and March 2021. The authors classified the 62 patients into 3 groups based on the classification system. All patients underwent rhinoplasty designed according to the corresponding classification. The patients were followed up after surgery, and the rhinoplasty outcomes evaluation (ROE) was used to evaluate their satisfaction rate. RESULTS: A total of 59 female patients and 3 male patients (mean age, 29.45 ± 7.73 years) were included in this study. Forty-five cases presented mild nasal contracture (72.58%), 11 presented moderate nasal contracture (17.74%), and 6 presented severe nasal contracture (9.68%). There were statistically significant differences in the number of prior rhinoplasty procedures, infection history, and preoperative ROE scores among the three groups, with no differences in sex ratio, age, kinds of initial implant materials, and postoperative ROE scores. Almost all patients achieved satisfactory outcomes after the revision surgery designed by different classifications. CONCLUSION: The authors have established a new classification system and treatment algorithm for contracted noses based on the change in pathological anatomy of nose, which is effective for guiding the treatment of contracted noses with good results.

Clinical impact of the type VI secretion system on clinical characteristics, virulence and prognosis of Acinetobacter baumannii during bloodstream infection.

The type VI secretion system (T6SS) has been regarded as a late-model virulence factor widely distributed in Acinetobacter baumannii (A. baumannii). This study aimed to elucidate the clinical manifestations, the genetic background and microbiological characteristics of A. baumannii isolates causing bloodstream infection (BSI), and assessed the impact of T6SS carrying state on the clinical course. In this study, Clinical samples of A. baumannii causing BSI were collected from a teaching hospital in China from 2016 to 2020 and a retrospective cohort was conducted. Experimental strains were categorized into T6SS positive and negative groups through PCR targeting on hcp gene. The antimicrobials sensitivity test, virulence genes, biofilm formation ability, serum resistance of A. baumannii strains and Galleria mellonella infection model were investigated. Independent risk factors for T6SS+ A. baumannii BSI and Kaplan-Meier curve through follow-up survey were analyzed. A total of 182 A. baumannii strains were isolated from patients with BSI during 5 years and the medical records of all patients were retrospectively reviewed. The proportion of T6SS+ isolates was 62.64% (114/182), which exhibited significantly higher resistance rates of commonly used antibacterial drugs compared to T6SS- group. We found that T6SS+ A. baumannii strains had significantly weaker biofilm formation ability compared to T6SS- A. baumannii. Despite no difference in the positivity rate of tested virulence genes in two groups, T6SS+ strains exhibited higher resistance to the serum and increased virulence in vivo compared to T6SS- strains, indicating that T6SS is likely to enhance the survival and invasive capabilities of A. baumannii in vivo. Indwelling catheter, respiratory diseases, ICU history, white blood cell count and percentage of neutrophils increasing were independent risk factors for T6SS+ A. baumannii BSI. At last, the Kaplan-Meier curve confirmed a higher mortality rate associated with T6SS+ A. baumannii BSI, suggesting that the presence of T6SS may serve as a prognostic factor for mortality. In conclusion, our study revealed that T6SS+ A. baumannii exhibited distinct clinical features, characterized by high antimicrobial resistance and enhanced virulence, providing valuable insights for clinical treatment considerations.

Synergy with farnesol rejuvenates colistin activity against Colistin-resistant Gram-negative bacteria in vitro and in vivo.

Colistin (COL) is considered the last line of treatment against infections due to multidrug-resistant (MDR) Gram-negative bacteria (GNB). However, the increasing number of colistin-resistant (COL-R) bacteria is a great threat to public health. In this study, a strategy of combining farnesol (FAR), which has anti-inflammatory and antitumor properties, with COL to restart COL activity was proposed. The synergistic effect of FAR combined with COL against COL-R GNB in vivo and in vitro were investigated. The excellent synergistic antibacterial activity of the COL-FAR combination was confirmed by performing the checkerboard assay, time-killing assay, and LIVE/DEAD bacterial cell viability assay. Crystal violet staining and scanning electron microscopy results showed that COL-FAR prevented biofilm formation and eradicated pre-existing mature biofilm. Cytotoxicity assay showed that FAR at 64 µg/mL was not cytotoxic to RAW264.7 cells. In vivo infection experiments showed that COL-FAR increased the survival rate of infected Galleria mellonella and decreased the bacterial load in a mouse thigh infection model. These results indicate that COL-FAR is a potentially effective therapeutic option for combating COL-R GNB infections.

When Combined with Pentamidine, Originally Ineffective Linezolid Becomes Active in Carbapenem-Resistant Enterobacteriaceae.

The increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) and their biofilm-relevant infections pose a threat to public health. The drug combination strategy provides a new treatment option for CRE infections. This study explored the synergistic antibacterial, antibiofilm activities as well as the in vivo efficacy against CRE of pentamidine combined with linezolid. This study further revealed the possible mechanisms underlying the synergy of the combination. The checkerboard and time-kill assays showed that pentamidine combined with linezolid had significant synergistic antibacterial effects against CRE strains (9/10). Toxicity assays on mammal cells (mouse RAW264.7 and red blood cells) and on Galleria mellonella confirmed that the concentrations of pentamidine and/or linezolid that were used were relatively safe. Antibiofilm activity detection via crystal violet staining, viable bacteria counts, and scanning electron microscopy demonstrated that the combination enhanced the inhibition of biofilm formation and the elimination of established biofilms. The G. mellonella infection model and mouse thigh infection model demonstrated the potential in vivo efficacy of the combination. In particular, a series of mechanistic experiments elucidated the possible mechanisms for the synergy in which pentamidine disrupts the outer membranes, dissipates the membrane potentials, and devitalizes the efflux pumps of CRE, thereby facilitating the intracellular accumulation of linezolid and reactive oxygen species (ROS), which ultimately kills the bacteria. Taken together, when combined with pentamidine, which acts as an outer membrane permeabilizer and as an efflux pump inhibitor, originally ineffective linezolid becomes active in CRE and exhibits excellent synergistic antibacterial and antibiofilm effects as well as a potential therapeutic effect in vivo on CRE-relevant infections. IMPORTANCE The multidrug resistance and biofilm formation of Gram-negative bacteria (GNB) may lead to incurable "superbug" infections. Drug combinations, with the potential to augment the original treatment ranges of drugs, are alternative treatment strategies against GNB. In this study, the pentamidine-linezolid combination showed notable antibacterial and antibiofilm activity both in vitro and in vivo against the problem carbapenem-resistant Enterobacteriaceae (CRE). Pentamidine is often used as an antiprotozoal and antifungal agent, and linezolid is a defensive Gram-positive bacteria (GPB) antimicrobial. Their combination expands the treatment range to GNB. Hence, the pentamidine-linezolid pair may be an effective treatment for complex infections that are mixed by GPB, GNB, and even fungi. In terms of mechanism, pentamidine inhibited the outer membranes, membrane potentials, and efflux pumps of CRE. This might be a universal mechanism by which pentamidine, as an adjuvant, potentiates other drugs, similar to linezolid, thereby having synergistic antibacterial effects on CRE.

A novel transposon Tn7540 carrying blaNDM-9 and fosA3 in chromosome of a pathogenic multidrug-resistant Salmonella enterica serovar Indiana isolated from human faeces.

OBJECTIVES: Emergence of multidrug-resistant (MDR) Salmonella enterica serovar Indiana has raised global concern. Mobile genetic elements (MGEs) play vital roles in accelerating the dissemination of resistance genes in bacteria communities. The study aims to improve our understanding of the underlying resistance mechanisms and characterize the MGEs in a MDR S. Indiana isolate. METHODS: Here, we report the characteristics of a MDR pathogenic S. Indiana isolate. The antimicrobial susceptibility pattern of S. Indiana QT6365 was determined. The genomic structure of the chromosome and the plasmid, serotype, and multi-locus sequence type were analysed by whole genome sequencing. The circular form derived from IS26-flanked transposon was confirmed by reverse polymerase chain reaction and sequencing. RESULTS: S. Indiana QT6365 exhibited resistance to all tested antimicrobials except for aztreonam, amikacin, polymyxin, and tigecycline, was defined as MDR, and belonged to ST17. S. Indiana QT6365 was closely related with food resource S. Indiana C629 with similar resistance gene profiles. Multiple resistance genes are mainly carried by a novel transposon Tn7540 located on the chromosome and an IncHI2/HI2A/N plasmid. Sequence analysis and the formed circular intermediate suggested Tn7540 might be generated through homologous recombination by IS26-bounded translocatable units (IS26-fosA-IS26-intI1-dfrA12-aadA2-sul1-ISCR1-blaNDM-9-IS26). CONCLUSIONS: To the best of our knowledge, this is the first report of the novel chromosomal transposon possessing blaNDM-9 and fosA3 in S. Indiana isolated from human specimen, which might facilitate the dissemination of resistance genes and should arouse serious awareness.

Carbapenemase-loaded outer membrane vesicles protect Pseudomonas aeruginosa by degrading imipenem and promoting mutation of antimicrobial resistance gene.

AIMS: To investigate the effect of Klebsiella pneumoniae carbapenemase (KPC)-loaded outer membrane vesicles (OMVs) in protecting Pseudomonas aeruginosa against imipenem treatment and its mechanism. METHODS: The OMVs of carbapenem-resistant Klebsiella pneumonia (CRKP) were isolated and purified from the supernatant of bacterial culture by using ultracentrifugation and Optiprep density gradient ultracentrifugation. The transmission electron microscope, bicinchoninic acid, PCR and carbapenemase colloidal gold assays were applied to characterize the OMVs. Bacterial growth and larvae infection experiments were performed to explore the protective function of KPC-loaded OMVs for P. aeruginosa under imipenem treatment. Ultra-performance liquid chromatography, antimicrobial susceptibility testing, whole-genome sequencing and bioinformatics analysis were used to investigate the mechanism of P. aeruginosa resistance phenotype mediated by OMVs. RESULTS: CRKP secreted OMVs loaded with KPC, which protect P. aeruginosa from imipenem through hydrolysis of antibiotics in a dose- and time-dependent manner. Furthermore, carbapenem-resistant subpopulations were developed in P. aeruginosa by low concentrations of OMVs that were confirmed to inadequately hydrolyze imipenem. Interestingly, none of the carbapenem-resistant subpopulations obtained the exogenous antibiotic resistance genes, but all of them possessed OprD mutations, which was consistent with the mechanism of P. aeruginosa induced by sub-minimal inhibitory concentrations of imipenem. CONCLUSIONS: OMVs containing KPC provide a novel route for P. aeruginosa to acquire an antibiotic-resistant phenotype in vivo.

The effectiveness of cell-derived exosome therapy for diabetic wound: A systematic review and meta-analysis.

BACKGROUND: The prevalence of diabetes among the elderly population is significant and rising annually. One of the most severe and frequent complications of diabetes mellitus is the diabetic wound, which has long-term negative effects on patients' finances, mental health, and functional abilities. Exosomes, a cell-free therapy, have emerged as a promising novel treatment for diabetic wounds, but their mechanism is still not entirely understood. Therefore, we conducted this meta-analysis to assess the effectiveness of exosomes in the management of diabetic wounds. METHODS: We searched PubMed, the Cochrane Library, EMBASE, and Web of Science for pertinent studies that described the therapeutic benefits of exosomes on diabetic wound models that were released before October 17, 2022. The outcome indicators consisted of wound healing rate, neovascular density, re-epithelialization rate, collagen deposition, scar width, and inflammatory factors. RevMan 5.4 software was used to conduct all statistical analyses. RESULTS: A total of 21 studies with 323 animals were identified in this meta-analysis. Pooled analyses demonstrated that exosome therapy was shown to be superior to control therapy in terms of wound healing rate (SMD = 5.42; 95 %CI = 4.40-6.44; P < 0.00001), neovascular density (SMD = 5.48; 95 %CI = 4.31-6.64; P < 0.00001), re-epithelialization rate (SMD = 5.06; 95 %CI = 3.75-6.37; P < 0.00001), collagen deposition (SMD = 4.78; 95 %CI = 3.58-5.98; P < 0.00001), scar width (SMD = -8.10; 95 %CI = -10.31 to -5.89; P < 0.00001). Additionally, the expression of inflammatory factors was significantly downregulated in the exosome treatment group. CONCLUSIONS: According to this meta-analysis of the current trials, exosome therapy can enhance the quality of diabetic wounds, especially when used in conjunction with novel dressings. To demonstrate the most efficient exosomes and therapeutic parameters for the treatment of diabetic wounds, future studies should conduct sizable, randomized, double-blind trials with high-quality, long-term follow-ups.

Genetic and Phenotypic Characterization of Multidrug-Resistant Klebsiella pneumoniae from Liver Abscess.

Cooccurrence of multidrug resistant (MDR) and hypervirulence phenotypes in liver abscess-causing Klebsiella pneumoniae (LAKp) would pose a major threat to public health. However, relatively little information is available on the genomic and phenotypic characteristics of this pathogen. This study aimed to investigate the virulence and resistance phenotype and genotype of MDR LAKp strains from 2016 to 2020. We collected 18 MDR LAKp strains from 395 liver abscess samples and characterized these strains using antimicrobial susceptibility test, string test, mucoviscosity assay, biofilm formation assay, Galleria mellonella killing assay, and whole-genome sequencing. Besides, phylogenetic and comparative genomic analyses were performed on these MDR LAKp, along with 94 LAKp genomes from global sources. Most of these MDR LAKp strains exhibited resistance to cephalosporins, quinolones, and chloramphenicol. Virulence assays revealed that only half of MDR LAKp strains exhibited higher virulence than classical MDR strain K. pneumoniae MGH78578. Importantly, we identified three ST11 KL64 hypervirulence carbapenem-resistant strains carrying blaKPC-2 and one colistin-resistant strain carrying mcr-1. Phylogenetic analysis revealed that 112 LAKp genomes were divided into two clades, and most of MDR LAKp strains in this study belonged to clade 1 (83.33%, 15/18). We also detected the loss of mucoviscosity mediated by mutations and ISKpn14 insertion in rmpA, and the latter representing a novel mechanism by which bacteria regulate RmpA system. This study provides novel insights into MDR LAKp and highlights the necessity for measures to prevent further spread of such organisms in hospital settings and the community. IMPORTANCE Pyogenic liver abscess is a potentially life-threatening suppurative infection of hepatic parenchyma. K. pneumoniae has emerged as a predominant pathogen of pyogenic liver abscess. Liver abscess-causing K. pneumoniae is generally considered hypervirulent K. pneumoniae and is susceptible to most antibiotics. Recently, convergence of multidrug resistant and hypervirulence phenotypes in liver abscess-causing K. pneumoniae was emerging and poses a major threat to public health. However, relatively little information is available on liver abscess-causing multidrug-resistant hypervirulent K. pneumoniae. In this study, we characterized phenotype and genotype of virulence and resistance of 18 multidrug-resistant hypervirulent liver abscess-causing K. pneumoniae strains collected from 395 pyogenic liver abscess cases in a tertiary teaching hospital over a 5-year period to enable in-depth understanding of this pathogen.

Evaluation of resazurin microplate method for rapid detection of vancomycin and linezolid resistance in Enterococcus faecalis and Enterococcus faecium clinical isolates.

BACKGROUND: Vancomycin and linezolid resistance among enterococci is an increasing problem due to a lack of alternative antibiotics. Early identification of vancomycin-resistant and linezolid-resistant strains can help prevent the spread of resistance to these antibiotics. Hence, early, rapid and accurate detection of vancomycin and linezolid resistance is critical. OBJECTIVES: The resazurin microplate method (RMM) was developed for detecting vancomycin and linezolid susceptibility among Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium) clinical isolates, and its performance was further evaluated. METHODS: A total of 209 non-duplicate clinical isolates and three strains from the faeces of domestic animals, including 142 E. faecalis (71 linezolid non-susceptible and 71 linezolid susceptible) and 70 E. faecium (23 vancomycin non-susceptible, 23 vancomycin susceptible, 12 linezolid non-susceptible and 12 linezolid susceptible), were tested using RMM. RESULTS: The susceptibility of E. faecium to vancomycin was detected within 5 h, with high susceptibility (23/23) and specificity (23/23). The susceptibility of E. faecalis and E. faecium to linezolid was detected within 4 h, with specificities of 98.59% and 100% and susceptibilities of 94.37% and 58.33% for E. faecalis and E. faecium, respectively. CONCLUSIONS: RMM had a good positive predictive value for the detection of vancomycin-non-susceptible E. faecium and linezolid-non-susceptible E. faecalis. It thus has the potential to become an alternative method for the rapid screening of these resistant pathogens in clinical practice.

A novel classification of alar retraction based on nostril exposure in Asian rhinoplasty.

OBJECTIVE: Alar retraction is considered a challenge in rhinoplasty. The classification of alar retraction remains poorly defined, especially in Asia. Patients with alar retraction are associated with excessive exposure to the nostrils in Asia. This study aimed to introduce a classification method of alar retraction based on nostril exposure. MATERIALS AND METHODS: Medical records of patients who had undergone rhinoplasty with alar retraction based on nostril exposure between January 2015 and December 2020 were retrospectively reviewed. The corrections of alar retraction were categorized into three groups according to a classification method of alar retraction based on nostril exposure: mild alar retraction, moderate alar retraction, and severe alar retraction. The visual analog scale (VAS) and rhinoplasty outcomes evaluation (ROE) were used to evaluate the satisfaction rate. RESULTS: Within a median period of 13.3 months, 45 patients (51.14%) with mild alar retraction were corrected by alar contour graft. 23 patients (26.14%) with moderate alar retraction were treated with the alar contour graft(n=10), the lateral crural strut graft (n = 6), and the alar projection graft (n = 7). 20 patients (22.73%) with severe alar retraction were corrected by lateral crural strut graft combined with composite graft (n = 6), lateral crural strut graft (n = 10), and composite graft (n = 4). The severe alar retraction group had a higher satisfaction rate in ROE(P<0.05) and VAS (P<0.05) than moderate alar retraction and mild alar retraction at a follow-up of 12 months after surgery. CONCLUSIONS: The classification of alar retraction based on nostril exposure is more practical for rhinoplasty in Asia.

In vitro antimicrobial activity and resistance mechanisms of the new generation tetracycline agents, eravacycline, omadacycline, and tigecycline against clinical Staphylococcus aureus isolates.

In this study, we investigated the in vitro activity and resistance mechanisms of the new generation tetracycline agents, namely eravacycline, omadacycline, and tigecycline, against Staphylococcus aureus isolates. A total of 1,017 non-duplicate S. aureus isolates were collected and subjected to susceptibility testing against eravacycline, omadacycline, and tigecycline using the broth microdilution method. Tetracyclines-resistant (eravacycline/omadacycline/tigecycline-resistant) isolates were selected to elucidate the resistance mechanisms using polymerase chain reaction (PCR), cloning experiment, efflux pump inhibition, and quantitative real-time PCR. The results of the antibacterial susceptibility testing showed that compared with omadacycline, eravacycline and tigecycline had superior antibacterial activity against S. aureus isolates. Among 1,017 S. aureus, 41 tetracyclines-resistant isolates were identified. These resistant isolates possessed at least one tetracycline resistance gene and genetic mutation in the MepRAB efflux pump and 30S ribosome units. A frameshift mutation in mepB was detected in most tetracyclines-resistant strains (except for JP3349) compared with tetracyclines-susceptible (eravacycline/omadacycline/tigecycline-susceptible) strains. This was first shown to decrease susceptibility to omadacycline, but not to eravacycline and tigecycline. After treatment with eravacycline, omadacycline or tigecycline, overexpression of mepA, tet38, tet(K) and tet(L) was detected. Moreover, multi-locus sequence typing showed a major clonal dissemination type, ST5, and its variant ST764 were seen in most tetracyclines-resistant strains. To conclude, eravacycline and tigecycline exhibited better activity against S. aureus including tetracycline-resistant isolates than omadacycline. The resistance to these new generation tetracyclines due to an accumulation of many resistance mechanisms.

Evaluation of the antibacterial, antibiofilm, and anti-virulence effects of acetic acid and the related mechanisms on colistin-resistant Pseudomonas aeruginosa.

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) has been majorly implicated in the infection of burns, wounds, skin, and respiratory tract. Colistin is considered the last line of defense against P. aeruginosa infections. However, colistin is becoming increasingly invalid in treating patients infected with colistin-resistant (COL-R) P. aeruginosa. As one of the disinfectants used for wound infections, acetic acid (AA) offers good antibacterial and antibiofilm activities against P. aeruginosa. This study investigated the effects of AA on COL-R P. aeruginosa in terms of its antibacterial, antibiofilm, and anti-virulence properties and the corresponding underlying mechanisms. RESULTS: The antimicrobial susceptibility and growth curve data revealed that 0.078% (v/v) AA exhibited good antibacterial activity against COL-R P. aeruginosa. Subinhibitory concentrations of AA were ineffective in inhibiting biofilm formation, but 4 × and 8 × of the minimum inhibitory concentration (MIC) was effective in removing the preformed biofilms in biofilm-eradication assays. The virulence results illustrated that AA inhibited COL-R P. aeruginosa swimming, swarming, twitching, and pyocyanin and elastase production. The analysis of the potential antibacterial mechanisms of AA on COL-R P. aeruginosa revealed that AA acted by increasing the outer and inner membrane permeability, polarizing the membrane potential, and decreasing the reduction potential in a concentration-dependent manner. The qRT-PCR results revealed that AA may inhibit the virulence of COL-R P. aeruginosa by inhibiting the expression of T3SS-related and QS-related genes. CONCLUSIONS: AA possesses antibacterial, antibiofilm, and anti-virulence properties that ultimately lead to the alteration of the bacterial membrane permeability, membrane potential, and reduction potential. Our findings indicated that AA is presently one of the effective treatment options for infections. A high concentration of AA (> 0.156% v/v) can be used to sterilize biofilm-prone surgical instruments, for hospital disinfection, and for treating the external wound, whereas a low concentration of AA (0.00975-0.039% v/v) may be used as an anti-virulence agent for adjuvant treatment of COL-R P. aeruginosa, thereby further improving the application value of AA in the treatment of infections.

A Selective Medium for Screening Ceftazidime/Avibactam Resistance in Carbapenem-Resistant Enterobacterales.

Ceftazidime/avibactam (CZA) is an alternative antibiotic used for the treatment of infections caused by carbapenem-resistant Enterobacterales (CRE). However, the CZA-resistant CRE strains have been detected worldwide. Therefore, it is critical to screen CZA-resistant CRE strains in colonized patients or a specific population so as to rapidly implement infection control measures to limit their transmission. In this study, we developed a Salmonella-Shigella (SS) CZA-selective medium and assessed its performance to screen for clinical CZA-resistant CRE isolates in both pure-strain specimens and stool samples. A total of 150 non-duplicated isolates, including 75 CZA-susceptible and 75 CZA-resistant CRE pathogens, were tested by using the broth microdilution method and the SS CZA medium, respectively. The bacterial suspensions were serially diluted in the SS CZA medium, which showed excellent screening performance in both pure CZA-resistant CRE strain and the stool samples with the lowest detection limit of 101-102 and 101-103 CFU/ml, respectively. Notably, none of the susceptible isolates showed growth even at the highest dilution concentration of 108 CFU/ml. Most importantly, the SS CZA medium demonstrated excellent performance in screening simulated clinical polymicrobial specimens. Moreover, its screening performance was unaffected by the different resistance determinants for tested isolates. Cumulatively, our data suggest that the SS CZA medium can be used as a promising selective medium to screen CZA-resistant CRE, irrespective of their resistance mechanisms.

Acquisition of Daptomycin Resistance by Enterococcus faecium Confers Collateral Sensitivity to Glycopeptides.

Daptomycin is a last-line antibiotic used in the treatment of multidrug-resistant Enterococcus faecium infections. Alarmingly, daptomycin-resistant E. faecium isolates have emerged. In this study, we investigated the evolution and mechanisms of daptomycin resistance in clinical E. faecium isolates and the corresponding acquisition of collateral sensitivity (CS) as an evolutionary trade-off. We evolved daptomycin resistance in six daptomycin-susceptible E. faecium isolates to obtain daptomycin-resistant mutants. The six E. faecium strains successfully acquired high-level resistance to daptomycin in vitro, but this led to fitness costs in terms of growth, in vitro competition, and virulence. Mutations in liaFSR, yycFG, and cls; increased surface positive charge; thicker cell walls; and elevated expression of dltABCD and tagGH were observed in daptomycin-resistant mutants. Surprisingly, we observed the emergence of CS in SC1762 isolates after the induction of daptomycin resistance. Compared with parental strains, the SC1174-D strain (i.e., daptomycin-resistant mutant of SC1174; non-CS) showed significantly upregulated expression of the vanA gene cluster. However, in SC1762-D (i.e., daptomycin-resistant mutant of SC1762), all vanA cluster genes except the vanX gene were obviously downregulated. Further in silico analyses revealed that an IS1216E-based composite transposon was generated in SC1762-D, and it disrupted the vanH gene, likely affecting the structure and expression of the vanA gene cluster and resulting in resensitization to glycopeptides. Overall, this study reports a novel form of CS between daptomycin and glycopeptides in E. faecium. Further, it provides a valuable foundation for developing effective regimens and sequential combinations of daptomycin and glycopeptides against E. faecium.