Contact dermatitis to polymyxin B

Contact Allergy to Polymyxin B Among Patients Referred for Patch Testing

BACKGOUND

Polymyxin B is not included in most standard contact allergen series. The aim of this study was to determine the prevalence of contact sensitization to polymyxin B in a population of patients referred for patch testing.

METHODS

A retrospective cohort study design was used to collect data on 795 patients referred to the contact dermatitis clinic of the McGill University Health Centre, as well as to the office of one of the authors (L.M.), between March 2014 and November 2015. Patients were patch tested to the North American Contact Dermatitis Group baseline series and polymyxin B sulfate 3% in petrolatum.

RESULTS

Out of 795 tested individuals, 18 were allergic to polymyxin B, for a prevalence of 2.3%. The eruptions affected almost all body parts, but mostly the face. The degree of reaction ranged from 1+ to 2+. Isolated reactions to polymyxin B occurred in 9 (50%) patients, whereas reactions to bacitracin and polymyxin B were seen in the other 9. Only 1 patient reacted to bacitracin, polymyxin B, and neomycin (11.1%). Most reactions (12/18) were from past exposure to polymyxin B.

CONCLUSIONS

Allergic reactions to polymyxin B are not rare, and this antibiotic warrants inclusion in the standard patch testing series.

Effect of Different Antibiotic Chemotherapies on Pseudomonas aeruginosa Infection In Vitro of Primary Human Corneal Fibroblast Cells

Pseudomonas aeruginosa is a major cause of bacterial keratitis (BK) worldwide. Inappropriate or non-optimal antibiotic chemotherapy can lead to corneal perforation and rapid sight loss. In this study, we tested the hypothesis that P. aeruginosa strain PAO1 invades primary human corneal fibroblasts (hCFs) in vitro and persists intracellularly, despite chemotherapy with antibiotics used commonly to treat BK. In rank order, ciprofloxacin, levofloxacin and polymyxin B showed the highest activity against planktonic PAO1 growth (100% inhibitory concentration ≤10 μg/mL; 50% inhibitory concentration ≤1 μg/mL), followed by gentamicin and ofloxacin (100% inhibitory concentration ≤50 μg/mL; 50% inhibitory concentration ≤10 μg/mL). These bactericidal antibiotics (50–200 μg/mL concentrations) all killed PAO1 in the extracellular environment of infected hCF monolayers. By contrast, the bactericidal antibiotic cefuroxime and the bacteriostatic antibiotic chloramphenicol failed to sterilize both PAO1 broth cultures, even at a concentration of ≥200 μg/mL) and infected hCF monolayers. Statistically, all antibiotics were able to prevent LDH release from PAO1-infected hCF monolayers at both concentrations tested. Intracellular Pseudomonas were significantly reduced (>99%, P < 0.05) following treatment with ciprofloxacin, levofloxacin and ofloxacin, whereas gentamicin, polymyxin B and cefuroxime failed to clear intracellular bacteria over 24 h. Intracellular Pseudomonas infection was resistant to chloramphenicol, with hCF death observed by 9 h. Eventual growth of remaining intracellular Pseudomonas was observed in hCF after removal of all antibiotics, resulting in re-infection cycles and cell death by 48 h. All of the antibiotics reduced significantly (P < 0.05) IL-1β secretion by hCF infected with a Multiplicity Of Infection (MOI) = 1 of PAO1. With higher MOI, no pro-inflammatory effects were observed with antibiotic treatment, expect with polymyxin B and ofloxacin, which induced significant increased IL-1β secretion (P < 0.001). The findings from our study demonstrated that bactericidal and bacteriostatic antibiotics, routinely used to treat BK, failed to eradicate Pseudomonas infection of hCFs in vitro and that their bactericidal efficacies were influenced by the cellular location of the organism.

Surgery-Related Contact Dermatitis: A Review of Potential Irritants and Allergens

Surgical procedures utilize an increasing number of medical products including antiseptics, anesthetics, gloves, suture materials, tissue adhesives, topical antibiotics, and bandages. Many of these products have irritant potential. Allergic contact dermatitis has also been reported. This review covers preoperative, operative, and postoperative exposures that may result in contact dermatitis. Testing with standard patch panels such as T.R.U.E. Test and the North American Contact Dermatitis Group 65 allergen series does not evaluate for all relevant contactants. A thorough understanding of potential exposures is vital to effectively evaluate a patient with surgery-related contact dermatitis. A systematic approach is needed to ensure that standard patch panels and supplementary patches adequately address each encountered contactant.

Anaphylactic Events Observed within 4 h of Ocular Application of an Antibiotic-Containing Ophthalmic Preparation: 61 Cats (1993–2010)

This study describes signalment, history, antibiotic administered, clinical signs observed, therapy, and outcome of anaphylactic events within 4 h following ophthalmic administration of an antibiotic to cats. Data came from survey responses (45 cats) or Federal Drug Administration reports (16 cats). Cat age (7 weeks—19 years), breed, and gender ranged widely. Most were healthy (87%) prior to anaphylaxis. Ophthalmic antibiotics commonly were administered for conjunctival (65%) or corneal (11%) disease, or ocular lubrication (7%) and contained bacitracin, neomycin, and polymyxin B (44%), or oxytetracycline and polymyxin B (21%). Polymyxin B was present in all cases. Vaccines or other drugs were also administered to 51% of cats. In 56% cases, anaphylaxis occurred within 10 min of drug application. Most (82%) cats survived. Although a causal association was not proved, ophthalmic antibiotic administration preceded anaphylaxis in all cats. Like other drugs, ophthalmic antibiotics should be used only when indicated.

A comparison of postprocedural wound care treatments: do antibiotic-based ointments improve outcomes?

BACKGROUND

Topical antibiotic ointments are commonly used for the postprocedural treatment of superficial wounds created during dermatologic procedures. We propose that antibiotics may not be necessary for healing these wounds, have the potential to cause allergic contact dermatitis, and may contribute to the development of antibiotic resistance.

OBJECTIVE

We sought to compare the efficacy and safety of a nonantibiotic, petrolatum-based ointment (Aquaphor Healing Ointment [AHO], Beiersdorf Inc, Wilton, CT) and an antibiotic-based first-aid ointment (Polysporin [Poly/Bac], Johnson & Johnson, New Brunswick, NJ) for the treatment of wounds created by removal of seborrheic keratoses.

METHODS

In this double-blind study, 30 subjects each had two seborrheic keratoses removed from their trunk or abdomen; one wound was treated with AHO and one with Poly/Bac twice daily. Clinical grading of wound healing and subjective irritation was assessed at days 7, 14, and 28 postwounding. Adverse events were recorded.

RESULTS

Clinical grading assessment showed no differences between wounds treated with AHO versus Poly/Bac for erythema, edema, epithelial confluence, crusting, and scabbing at any time point. Subjective irritation assessment showed wounds treated with Poly/Bac had a significant increase in burning at week 1, whereas no differences were seen between treatments for stinging, itching, tightness, tingling, or pain. One case of allergic contact dermatitis was reported after Poly/Bac treatment.

LIMITATIONS

This was a relatively small study.

CONCLUSIONS

This study demonstrated that the petrolatum-based skin protectant ointment AHO provided equivalent efficacy for wound healing as a combination antibiotic first-aid ointment. Antibiotics may not be necessary to achieve satisfactory wound healing and may cause allergic contact dermatitis.