Focusing on Gordonia Infections: Distribution, Antimicrobial Susceptibilities and Phylogeny.

The immunosuppression conditions and the presence of medical devices in patients favor the Gordonia infections. However, the features of this aerobic actinomycete have been little explored. Strains (n = 164) were characterized with 16S rDNA and secA1 genes to define their phylogenetic relationships, and subjected to broth microdilution to profile the antimicrobial susceptibilities of Gordonia species that caused infections in Spain during the 2005-2021 period. Four out of the eleven identified species were responsible for 86.0% of the infections: Gordonia sputi (53.0%), Gordonia bronchialis (18.3%), Gordonia terrae (8.5%) and Gordonia otitidis (6.1%). Respiratory tract infections (61.6%) and bacteremia (21.9%) were the most common infections. The secA1 gene resolved the inconclusive identification, and two major clonal lineages were observed for G. sputi and G. bronchialis. Species showed a wide antimicrobial susceptibility profile. Cefoxitin resistance varies depending on the species, reaching 94.2% for G. sputi and 36.0% for G. terrae. What is noteworthy is the minocycline resistance in G. sputi (11.5%), the clarithromycin resistance in G. bronchialis secA1 lineage II (30.0%) and the amoxicillin-clavulanate and cefepime resistance in G. terrae (21.4% and 42.8%, respectively). G. sputi and G. bronchialis stand out as the prevalent species causing infections in Spain. Resistance against cefoxitin and other antimicrobials should be considered.

Exploring the genetic background of the botulism neurotoxin BoNT/B2 in Spain.

To determine whether the neurotoxin BoNT/B2 causing botulism in Spain is clonal, the genetic diversity and phylogenetic relationships of Clostridium botulinum from food-borne episodes and infant cases of the condition were explored. The botulinum toxin gene (bont) subtype, the variable region of the flagellin gene (flaVR), and a seven-gene multi-locus sequence type were examined by sequencing 37 BoNT-positive cultures obtained over the period 2010 to 2022. Out of 37 botulism events, 16 food-borne episodes and 16 infant cases were associated with bont/b2. Eight bont/b2 alleles were detected [nucleotide distance range 0.0259-0.415%, Hunter and Gaston discrimination index (HGDI) 0.71]. The most common bont/b2 allele corresponded to that of strain Prevot 25 NCASE and its single and double locus variations (87.5%). Four known flaVR types were identified (HGDI 0.79), along with one previously unknown (flaVR-15). Sixteen sequence types (STs) (HGDI 0.89) were recorded including seven new STs (ST164-ST170; 10 new alleles) and five new STs (ST171-ST175; with new allele combinations) were also noted. Correlations among some STs and flaVR types were seen. Overall, the present results show that the combined analysis of bont/b2-flaVR-ST at the nucleotide level could be used to track botulism events in Spain. The neurotoxin BoNT/B2 has largely been responsible for human botulism in Spain. The polymorphism analysis of bont/b2, flaVR typing, and sequence type determinations, revealed a wide variety of clones to be responsible for human botulism, ruling out a common source of acquisition. IMPORTANCE Botulism, a potentially fatal disease, is classically characterized by a symmetrical descending flaccid paralysis, which if left untreated can lead to respiratory failure and death. Botulinum neurotoxin (BoNT), produced by certain species of Clostridium, is the most potent biological toxin known, and the direct cause of botulism. This study characterizes the acquisition in Spain of two forms of botulism, i.e., food-borne and infant botulism, which are largely caused by the main neurotoxin BoNT/B2. Polymorphism analysis of the bont/b2 gene, typing of the flagellin variable region sequence (flaVR), and multilocus sequence typing, were used to explore the genetic background of Clostridium botulinum group I. To our knowledge, this is the first phylogenetic and typing study of botulism undertaken in Spain.

Amniotic Membrane Restores Chronic Wound Features to Normal in a Keratinocyte TGF-ß-Chronified Cell Model.

Unsuccessful wound closure in chronic wounds can be linked to altered keratinocyte activation and their inability to re-epithelize. Suggested mechanisms driving this impairment involve unbalanced cytokine signaling. However, the molecular events leading to these aberrant responses are poorly understood. Among cytokines affecting keratinocyte responses, Transforming Growth Factor-ß (TFG-ß) is thought to have a great impact. In this study, we have used a previously characterized skin epidermal in vitro model, HaCaT cells continuously exposed to TGF-ß1, to study the wound recovery capabilities of chronified/senescent keratinocytes. In this setting, chronified keratinocytes show decreased migration and reduced activation in response to injury. Amniotic membrane (AM) has been used successfully to manage unresponsive complicated wounds. In our in vitro setting, AM treatment of chronified keratinocytes re-enabled migration in the early stages of wound healing, also promoting proliferation at later stages. Interestingly, when checking the gene expression of markers known to be altered in TGF-ß chronified cells and involved in cell cycle regulation, early migratory responses, senescence, and chronic inflammation, we discovered that AM treatment seemed to reset back to keratinocyte status. The analysis of the evolution of both the levels of keratinocyte activation marker cytokeratin 17 and the spatial-temporal expression pattern of the proliferation marker Ki-67 in human in vivo biopsy samples suggests that responses to AM recorded in TGF-ß chronified HaCaT cells would be homologous to those of resident keratinocytes in chronic wounds. All these results provide further evidence that sustained TGF-ß might play a key role in wound chronification and postulate the validity of our TGF-ß chronified HaCaT in vitro model for the study of chronic wound physiology.

Chronic Wound Healing by Amniotic Membrane: TGF-ß and EGF Signaling Modulation in Re-epithelialization.

The application of amniotic membrane (AM) on chronic wounds has proven very effective at resetting wound healing, particularly in re-epithelialization. Historically, several aspects of AM effect on wound healing have been evaluated using cell models. In keratinocytes, the presence of AM induces the activation of mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK) pathways, together with the high expression of c-Jun, an important transcription factor for the progression of the re-epithelialization tongue. In general, the levels of transforming growth factor (TGF)-ß present in a wound are critical for the process of wound healing; they are elevated during the inflammation phase and remain high in some chronic wounds. Interestingly, the presence of AM, through epidermal growth factor (EGF) signaling, produces a fine-tuning of the TGF-ß signaling pathway that re-conducts the stalled process of wound healing. However, the complete suppression of TGF-ß signaling has proven negative for the AM stimulation of migration, suggesting that a minimal amount of TGF-ß signaling is required for proper wound healing. Regarding migration machinery, AM contributes to the dynamics of focal adhesions, producing a high turnover and thus speeding up remodeling. This is clear because proteins, such as Paxillin, are activated upon treatment with AM. On top of this, AM also produces changes in the expression of Paxillin. Although we have made great progress in understanding the effects of AM on chronic wound healing, a long way is still ahead of us to fully comprehend its effects.

Prophylactic Use of Negative Pressure Therapy in General Abdominal Surgery: A Systematic Review and Meta-Analysis.

Background: Surgical site infections (SSIs) represent an economic burden to healthcare systems. The use of negative pressure wound therapy (NPWT) for SSI prophylaxis remains uncertain. Methods: A systematic literature search was conducted in Medline/PubMed, CINAHL, and Web of Science for relevant studies. The primary outcome was the evaluation of the effectiveness of NPWT for prophylaxis of SSI rates in general abdominal surgery. Secondary outcomes were rates of seroma and wound dehiscence, length of hospital stay, and re-admission rates. The statistical analysis was performed with random effect models. Results: A total of 3,193 patients from 20 articles (six randomized controlled trials [RCT], three prospective, eight retrospective, and three ambispective studies) were analyzed. Negative pressure wound therapy was associated with decreased rate of SSIs compared with standard dressing in a pooled analysis of non-randomized studies and RCTs (0.57; 95% confidence interval [CI], -0.4 to 0.8; p < 0.001). This result, however, needs to be challenged because of a significant statistical heterogeneity of the included studies (I2 = 71%; p < 0.01). A separate analysis of the six RCTs failed to confirm the superiority of NPWT (0.64; 95% CI, -0.4 to 1.04; p = 0.07), also disclosing significant heterogeneity. The analysis of secondary outcomes was only possible in combination of randomized and non-randomized studies because of incomplete datasets in RCTs. Re-admission rates were lower after NPWT and no difference was observed for the incidence of seroma, wound dehiscence, and length of hospital stay. Conclusions: Based on available evidence, the routine use of NPWT for SSI prophylaxis after laparotomy in general abdominal surgery cannot be generally recommended.

Use of cryopreserved human amniotic membrane in the treatment of skin ulcers secondary to calciphylaxis.

Calciphylaxis is a rare condition characterized by skin ulceration and necrosis as a result of vascular calcification of the small and medium blood vessels of skin and subcutaneous tissues. It mainly occurs in patients with advanced chronic kidney disease and sometimes leads to complications with a fatal outcome. In this report, we describe the case of a 67-year-old male patient with end stage renal disease presenting painful skin ulcers on his lower limbs. The lesions had progressively grown and were associated to severe pain and decreased quality of life. The ulcers did not respond to conventional treatments and the patient underwent skin biopsy of these lesions obtaining anatomopathological findings compatible with calciphylaxis. In this report, we present an innovative treatment for skin ulcers secondary to calciphylaxis using cryopreserved amniotic membrane (AM) as a dressing in order to promote epithelialization of the wounds. After four applications, healing of the main ulcer and reduction in pain was achieved. In summary, applying cryopreserved AM probed to be a promising strategy to reduce pain and to enhance epithelialization and healing of chronic non-responsive ulcers in calciphylaxis.

Cryopreserved amniotic membrane in the treatment of diabetic foot ulcers: a case series.

OBJECTIVE: The amniotic membrane (AM) is a tissue with low immunogenity and high therapeutic potential due to its anti-inflammatory, anti-fibrotic and antimicrobial effects. This paper describes the use of cryopreserved amniotic membrane allografts to treat diabetic foot ulcers (DFUs) in patients with diabetes. METHOD: In this case series, AM was processed to obtain a final medicinal product: cryopreserved amniotic membrane. cryopreserved AM was applied every 7-10 days until total epithelialisation of the DFUs. RESULTS: A total of 14 patients with DFUs (median size: 12.30cm, (range: 0.52-42.5cm2) were treated and followed up until complete closure (median time: 20 weeks, range: 7-56 weeks). Patients received 4-40 AM applications. All patients in this study achieved complete epithelialisation of the wound. No adverse events were observed. CONCLUSION: AM is a feasible and safe treatment in complex DFUs. Furthermore, the treatment is successful in achieving epithelialisation of long-evolution, unhealed wounds resistant to conventional therapies.