Polygalacturonic acid partially inhibits matrix metalloproteinases and dehydration in wounds.

BACKGROUND: Key wound environment parameters include pH, hydration, and the balance between tissue remodeling and deposition of new tissue. When prolonged inflammation is present, the proliferation phase of wound healing can be delayed because excessive protease production due to persistent inflammation can destroy newly formed tissue and prevent wounds from filling and reepithelializing. OBJECTIVE: To conduct an in vitro study of the ability of polygalacturonic acid (PG), a natural pectin derivative present in ripening fruit, to inhibit 3 destructive wound proteases and prevent dehydration in environments in which significant evaporation can occur. MATERIALS AND METHODS: In vitro enzyme inhibition assay kits were used to detect the ability of PG to inhibit key wound proteases matrix metalloproteinase (MMP)-2, MMP-9, and neutrophil elastase (NE). Transepidermal evaporative water loss from a polyvinyl alcohol skin substitute hydrogel was gravimetrically measured. RESULTS: PG could partially inhibit MMP-2 (>50% inhibition relative to negative controls), MMP-9 (>50% inhibition relative to negative controls), and NE (>25% inhibition relative to negative controls) and thereby potentially blunt some of the destructive effects of excess proteases where prolonged inflammation is present. In an in vitro transepidermal evaporative water loss assay, PG also helped retain moisture and inhibited dehydration (>25% reduction relative to negative controls). CONCLUSIONS: These findings suggest that PG can be a useful addition to ointments and dressings in wound care and warrants further in vivo testing.

In vitro activity of cefepime/taniborbactam and comparator agents against Gram-negative bacterial bloodstream pathogens recovered from patients with cancer.

Background: Taniborbactam is a ß-lactamase inhibitor that, when combined with cefepime, may offer a potential treatment option for patients with serious and resistant Gram-negative bacterial (GNB) pathogens. Objectives: This study evaluated in vitro activity of cefepime/taniborbactam and comparator agents against GNB pathogens isolated from patients with cancer at our institution. Methods: A total of 270 GNB pathogens (2019-23) isolated from patients with cancer were tested against cefepime/taniborbactam and comparator agents commonly used for these patients. CLSI-approved broth microdilution methods were used. MIC50, MIC90, MIC range and percentage of susceptibility calculations were made using FDA breakpoints when available. Results: Cefepime/taniborbactam showed highly potent activity against tested Enterobacterales, including isolates producing ESBLs and carbapenem-resistant Enterobacterales. At a provisional breakpoint of ≤16/4 mg/L, cefepime/taniborbactam inhibited most tested species of GNB pathogens, with overall 98.9% susceptibility, which was significantly (P < 0.0001) higher than the susceptibility of the GNB isolates to all other tested comparator agents, ranging from 39.6% for cefepime to 86.3% for ceftazidime/avibactam. Conclusions: Our results showed that taniborbactam in combination with cefepime improved in vitro activity against GNB pathogens isolated from patients with cancer, including MDR Pseudomonas aeruginosa, carbapenem-resistant Enterobacterales, ESBL-producing Enterobacterales and Stenotrophomonas maltophilia isolates, with highest activity compared with all tested comparator agents, including other ß-lactam/ß-lactamase inhibitor combinations. Further studies are warranted to explore the efficacy of cefepime/taniborbactam for empirical initial treatment of GNB infections in cancer patients with high rates of febrile neutropenia requiring hospitalization.

Review of allergic reactions from use of chlorhexidine on medical products in clinical settings over 40 years: Risks and mitigations.

Chlorhexidine is an antimicrobial agent widely used for infection prevention in medical settings. Nevertheless, allergic reactions ranging from mild to severe have been reported following its use. In this review, we analyzed all case reports published between the introduction of chlorhexidine and the end of 2019 for allergic responses associated with the use of medical devices and or other medical products containing chlorhexidine (CHX) to ascertain the prevalence of severe CHX allergic reactions and what practices might best mitigate those risks.In total, 77 publications containing 124 reported cases of allergic reactions were grouped into 3 product categories, catheters, semisolids, and fluid products. The country, type of reaction, route of sensitization, allergy confirmation, and intervention or mitigation was extracted for each case. Overall, 30 cases were associated with catheters, 46 cases were associated with semisolid products, and 48 cases were associated with the use of other medical products. Severe cases were managed with intravenous fluids, steroids, and epinephrine (adrenaline). None of the reported cases were fatal. The allergy risks can be mitigated by better warning and training clinicians and by recording and screening patient histories for CHX presensitization from prior exposure. For patients undergoing pre-use blood tests, IgE antibody screens can also be performed. Finally, as a precaution in the event a rare severe allergic reaction occurs, procedure carts and rooms can be prestocked with injectable epinephrine and other rapidly acting anti-inflammatory medications.

Enhanced Biofilm Eradication and Reduced Cytotoxicity of a Novel Polygalacturonic and Caprylic Acid Wound Ointment Compared with Common Antiseptic Ointments.

Antiseptic wound ointments are widely used to treat dermal wounds that are microbially contaminated. Polygalacturonic acid (PG)+caprylic acid (CAP) is a novel combination that has been shown to eradicate biofilms. We developed a novel PG+CAP ointment and compared the biofilm eradication capability and cytotoxicity of PG+CAP with that of commercially available antiseptic wound ointments. We used a well-established biofilm model to quantitatively assess the eradication of organisms following exposure to the wound ointments for 2 hours. PG+CAP ointment completely eradicated Candida albicans, multidrug-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus biofilms, whereas MediHoney, polyhexamethylene biguanide (PHMB), and benzalkonium chloride (BZK) ointments failed to eradicate all biofilms within 2 hours. We assessed cytotoxicity by exposing L-929 fibroblasts to extracts of each ointment; Trypan blue exclusion was used to assess cell viability, and Alamar blue conversion was used to assess metabolic function. After exposure to PG+CAP and MediHoney, fibroblast viability was 96.23% and 95.23%, respectively (Trypan blue), and was comparable to untreated cells (98.77%). PHMB and BZK showed reduced viability (83.25% and 77.83%, respectively, p < 0.05). Metabolic activity results followed a similar pattern. Cytotoxicity of PG+CAP ointment towards erythrocytes was comparable to saline. PG+CAP ointment seems to be safe and can rapidly eradicate microbial biofilm; thus, PG+CAP ointment merits further in vivo testing as a potential antimicrobial wound ointment.