Topical antibacterial agents

Evaluation of the risk of incisional infection in horses following application of protective dressings after exploratory celiotomy for treatment of colic

OBJECTIVE To assess incidence of incisional infection in horses following management with 1 of 3 protective dressings after exploratory celiotomy for treatment of acute signs of abdominal pain (ie, colic) and determine the risk of complications associated with each wound management approach. DESIGN Prospective, randomized, controlled study. ANIMALS 85 horses. PROCEDURES Horses were assigned to 3 groups. After standardized abdominal closure, a sterile cotton towel (group 1) or polyhexamethylene biguanide-impregnated dressing (group 2) was secured over the incision site with 4 or 5 cruciate sutures of nonabsorbable monofilament, or sterile gauze was placed over the site and secured with an iodine-impregnated adhesive drape (group 3). Demographic and clinicopathologic data, intraoperative and postoperative variables, and development of complications were recorded and compared among groups by statistical methods. Follow-up information was collected 30 and 90 days after surgery. Incidence and odds of incisional complications were calculated. RESULTS 75 horses completed the study. Group 3 typically had dressing displacement necessitating removal during anesthetic recovery; dressings were in place for a mean of 44 and 31 hours for groups 1 and 2, respectively. Purulent or persistent serosanguinous incisional discharge (ie, infection) was detected in 11 of 75 (15%) horses (2/24, 0/26, and 9/25 from groups 1, 2, and 3, respectively). Odds of incisional complications were significantly greater for group 3 than for groups 1 or 2. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that risk of infection after celiotomy for treatment of colic is lower for incisions covered with sterile towels or polyhexamethylene biguanide-impregnated dressings secured with sutures than for incisions covered with gauze secured with iodine-impregnated adhesive drapes.

Higher functionality of bacterial plasmid DNA in water after peracetic acid disinfection compared with chlorination

Peracetic acid (PAA) is an emerging disinfectant with a low disinfection by-product formation potential, but how PAA destroys gene function after killing bacteria remains to be studied. Bacterial plasmid DNA is a mobile genetic element that often harbors undesirable genes encoding antibiotic resistance and virulence factors. Even though PAA efficiently kills bacteria, bacterial plasmids and other mobile genetic elements might still be intact and functional after PAA disinfection, posing potential public health and environmental risks. This study evaluated the impact of PAA disinfection on the functionality of plasmid DNA in vivo and compared the results with those from chlorination. We delivered a plasmid DNA harboring two antibiotic resistance genes to Escherichia coli TOP10 to form an antibiotic-resistant bacterium (ARB). The planktonic ARB was treated with PAA and chlorine to find the minimum doses inhibiting the regrowth of the strain. PAA and chlorine stopped the regrowth at 8 ± 1 mg PAA·L^-1 and 20 ± 9 mg Cl₂·L^-1, respectively. The functionality of the plasmid DNA after PAA and chlorine disinfection was then determined at higher doses in vivo. Neither PAA nor chlorine completely destroyed the plasmid DNA. However, chlorine was more efficient than PAA in eliminating the plasmid DNA. PAA at 25 mg PAA·L^-1 reduced the transforming activity of the plasmid DNA by less than 0.3 log₁₀ units, whereas chlorine at 25 mg Cl₂·L^-1 reduced the transforming activity by approximately 1.7 log₁₀ units. Chlorine had a more pronounced impact on the functionality of the plasmid DNA because it oxidizes or destroys bacterial components including plasmid DNA faster than PAA. In addition, environmental scanning electron microscopy shows that chlorination desiccated the cells resulting in the flat cellular structure and possibly more complete loss of plasmid DNA, whereas PAA disinfection had a less impact on cell structure and morphology. This study demonstrates that more plasmid DNA remains functional in water after PAA disinfection than after chlorination. These functional genetic elements could be acquired by other microorganisms via horizontal gene transfer to pose potential public health and environmental risks.

PREVALENCE OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS IN SPINAL SURGERY PATIENTS

ABSTRACT Objective The objective of this study was to determine the prevalence of patients with colonization of methicillin-resistant Staphylococcus aureus (MRSA) in the nasal mucosa, who underwent elective spinal procedures. Methods Retrospective study of the medical records of all patients submitted to elective procedures, totaling 125 individuals in the period of 2015 and 2017, performed by two spinal surgeons of the Orthopedics and Traumatology Service of Hospital Mater Dei, Belo Horizonte, Minas Gerais. The pre-operative investigation of MRSA consisted of the collection of a nasal swab for microbiological culture. Results Of the 125 patients evaluated, three (2.4%) showed positive results for MRSA nasal colonization. This prevalence is consistent with the international literature, that ranges from 1.5 to 5.9%. Of these patients none had infection of the surgical wound, probably due to the preoperative prophylactic measures. Conclusions Despite the limitations of the study, we found that the prevalence of carriers of this nasal MRSA population is similar to that of populations worldwide . Level of evidence III; Retrospective Study.

A Review of Antibiotics in Dermatology

Background:

Since the early 1930s when antibiotics were first introduced, they have revolutionized the way physicians treat infections. Skin conditions from acne to leprosy, which were once shunned by society, are now easily treated with oral antibiotics.

Objective:

Antibiotics are chemicals derived from bacteria and fungi that uniquely have antibacterial action. The most notable example is penicillin, which is derived from a mold. With hundreds of antibiotics available to the practicing physician, improper use of these drugs has become widespread and expensive and has spawned resistant strains. For the dermatologist, antibiotics are vital weapons in the drug armamentarium for treating various skin conditions.

Conclusion:

This review explores the newest and most common oral, parenteral, and topical antibiotics used in dermatology, their indications, adverse effects, dosage, and spectrum of activity. Furthermore, systemic antibacterial prophylaxis and vaccines pertinent to dermatology are discussed. The penicillins, cephalosporins, tetracyclines, macrolides, fluoroquinolones, sulfonamides, aminoglycosides, lincosamides, folate inhibitors, and a new synthetic class of drugs, the oxazolidinones, are reviewed. These antibiotics are used to treat a variety of organisms.

Topical triple-antibiotic ointment as a novel therapeutic choice in wound management and infection prevention: a practical perspective

Triple-antibiotic ointment (TAO) is a safe and effective topical agent for preventing infections in minor skin trauma. The formulation contains neomycin, polymyxin B and bacitracin in a petrolatum base. TAO is active against the most common disease-causing pathogens found in wounds and on the skin and may be an attractive alternative to oral therapy in select circumstances. Resistance to TAO does not develop readily, and safety studies have shown that the risk of allergic sensitivity to TAO is low. Susceptibility profiles of TAO have remained relatively unchanged since its discovery. Prophylaxis or treatment with TAO should be considered as resistant organisms continue to emerge in the community and hospital setting.

Management of hot tar burn using vitamin e ointment containing petroleum and polyoxyethylene sorbitan

Tar burns are primarily an occupational hazard associated with the road paving or roofing industry. Management of tar burns requires safe and effective removal of solidified tar from the skin using a dissolution or emulsifying agent to prevent inflicting further injury and pain. We report a case of a patient with tar burns on 10% of his body surface area involving the lower arms bilaterally and splashes to the facial area. The tar was efficiently removed with Webber Vitamin E Ointment without toxicity, irritation, or other complications.

Postprocedural wound-healing efficacy following removal of dermatosis papulosa nigra lesions in an African American population: a comparison of a skin protectant ointment and a topical antibiotic

BACKGROUND

Removal of dermatosis papulosa nigra (DPN) lesions results in superficial cutaneous wounds that are frequently treated with topical antibiotic ointments. We hypothesize that antibiotics are not necessary for effective and safe healing of such wounds.

OBJECTIVE

This study compared the wound healing efficacy and safety of the skin protectant Aquaphor Healing Ointment (AHO) (Beiersdorf Inc, Wilton, CT) and Polysporin first-aid ointment (Poly/Bac) (polymyxin B sulfate/bacitracin zinc) (Johnson & Johnson, New Brunswick, NJ) after removal of DPN lesions.

METHODS

This double-blind, split-face, pilot study removed two DPN lesions from each side of the face of 20 African American subjects. Wounds on opposite sides of the face were treated with AHO or Poly/Bac twice daily for 21 days. Wounds were evaluated for erythema, edema, crusting, scabbing, epithelial confluence, melanin confluence, general wound appearance, and subjective irritation on days 1, 3, 7, 10, 14, and 21 after surgery using 5-point scales.

RESULTS

Wound healing parameter assessments showed no differences between wounds treated with AHO versus Poly/Bac in erythema, edema, epithelial confluence, crusting, scabbing, melanin confluence, or postinflammatory hyperpigmentation at any time point. Subjective irritation was similar between treatments for burning, stinging, itching, tightness, tingling, and pain. No adverse events were reported.

LIMITATIONS

This was a small study in a homogenous population of African Americans.

CONCLUSIONS

Postprocedural treatment with AHO and Poly/Bac demonstrated equivalent wound healing in an African American population. These results support the hypothesis that antibiotics are not necessary for safe and effective healing of facial wounds resulting from removal of DPN lesions.

A comparison of antibacterial activity against Methicillin-Resistant Staphylococcus aureus and gram-negative organisms for antimicrobial compounds in a unique composite wound dressing

OBJECTIVE

Antibiotic resistance is increasing among organisms that commonly cause wound infections. Therefore, it becomes increasingly desirable to prevent wound infections as systemic antibiotic treatment of established wound infections becomes more difficult, more expensive, and potentially more toxic. The ability to incorporate antimicrobial compounds into modern wound dressings provides an opportunity to prevent wound infections without the risk of systemic toxicity, thus diminishing morbidity, mortality, and cost to the healthcare system.

DESIGN

In these studies, the authors tested 16 antimicrobial agents in a unique composite wound dressing (TheraGauze; Soluble Systems, LLC, Newport News, Virginia) against clinical methicillin-resistant Staphylococcus aureus isolates and Gram-negative organisms commonly associated with wound infections and antibiotic resistance. Disk diffusion susceptibility testing is used to quantify antimicrobial activity.

RESULTS

Broad-spectrum antimicrobial activity was found for the following agents in the composite wound dressing: hydrogen peroxide, tobramycin, chlorhexidine digluconate, chlorhexidine gluconate, levofloxacin, and silver.

CONCLUSION

These studies suggest that potent local antibacterial activity can be achieved with several antimicrobials in this wound dressing.

A comparison of the prophylactic uses of topical mupirocin and nitrofurazone in murine crush contaminated wounds

OBJECTIVES

This work was conducted to study the prophylactic efficacy of 2 topical antibiotic ointments (mupirocin and nitrofurazone) against wound infection in experimental contaminated crush wounds.

METHODS

Male Wistar rats underwent two 2-cm incisions at the back side and randomized into 3 groups--placebo (n = 14), mupirocin (n = 14), and nitrofurazone (n = 14)--and infected with either Staphylococcus aureus or S. pyogenes. All wound edges were crushed for 5 seconds with hemostats to simulate crush injury before inoculation of the microorganisms. Half of the wounds were sutured and the other half left open. These wounds were treated 3 times daily for 6 days with topical mupirocin, nitrofurazone, or petrolatum (as placebo). At the end of 6 days, excisional biopsies were taken from wound edges and histopathologic assessments were made based on neutrophilic infiltration, edema formation, myofibroblastic proliferation, and granulation tissue formation. For the microbiologic assessments, quantitative tissue cultures were made.

RESULTS

In S. aureus-inoculated wounds, mupirocin showed higher antibacterial activity against bacterial colonization and reduced infection rates compared to placebo groups. The same effect was observed for the infection rates in S. pyogenes-inoculated wounds. In S. pyogenes-inoculated open wounds, nitrofurazone showed higher antibacterial activity against infection, but this effect was not observed in closed wounds. In S. pyogenes- and S. aureus-infected wounds, mupirocin treatment significantly lowered infection rates compared to nitrofurazone treatment. Histopathologic examination showed higher myofibroblastic proliferation and higher volume of granulation tissue in the nitrofurazone groups compared to the mupirocin groups.

CONCLUSION

Topical mupirocin application was effective against crush wound infections inoculated with S. pyogenes and S. aureus. Nitrofurazone provides better granulation tissue formation, but did not effectively prevent bacterial colonization and infection in crush contaminated wounds.

Allergic contact dermatitis to topical antibiotics: Epidemiology, responsible allergens, and management

Topical antibiotics are widely used to treat cutaneous, ocular, and otic infections. Allergic contact dermatitis to topical antibiotics is a rare but well-documented side effect, especially in at-risk populations. The purpose of this article is to review the epidemiology, responsible allergens, and management of allergic contact dermatitis to topical antibiotics.

LEARNING OBJECTIVE

After completing this learning activity, participants should be able to describe the epidemiology of allergic contact dermatitis related to topical antibiotics; show knowledge of the most common allergenic topical antibiotics; and understand the allergenic cross-reactivity pattern amongst topical antibiotics.

Topische Antibiotika zur Therapie von Hautinfektionen

To understand the development of bacterial resistance and multi-resistance following treatment with topical and systemic antibiotics is important for dermatologists. Furthermore the sensitization potential and toxicity of antibiotics applied to large skin areas must be considered. The advantage of many topical antibiotics is evident; extremely high concentrations can be achieved in the infected skin usually without any systemic side effects. When an antibiotic is used both systemically and topically, indications should be weighed carefully for topical use, in order to reduce the likelihood of sensitization to an potential systemic agent. Continuous monitoring of the resistance profile of important bacteria is also desirable, in order to preserve the utility of important "reserve antibiotics". In this review the most important topical antibiotics used in Germany are evaluated with regards to efficacy and safety profile.

In Vitro Efficacy of a Polyhexamethylene Biguanide-Impregnated Gauze Dressing Against Bacteria Found in Veterinary Patients

OBJECTIVE

To evaluate the in vitro efficacy of polyhexamethylene biguanide (PHMB)-impregnated gauze dressing in limiting the growth of bacteria both within and underneath the dressing.

STUDY DESIGN

In vitro study.

METHODS

Squares of PHMB-impregnated and control gauze were placed on agar plates inoculated with 1 of 11 bacterial species, including 8 multi-resistant organisms. Growth under the gauze was assessed qualitatively after 24-hour incubation. Repeated use of sponges was used to evaluate residual inhibitory activity against Micrococcus lutea and Staphylococcus schleiferi ss. schleiferi. In a second procedure, PHMB-impregnated and control gauze squares were placed in sterile plastic wells and inoculated with 1 of 5 bacterial species, including Pseudomonas spp. and Klebsiella spp. Inhibition of bacterial growth within and underneath the dressing after 24-hour incubation was evaluated by quantifying the numbers of bacteria on the well floor and within each square.

RESULTS

PHMB-impregnated gauze provided greater inhibition of growth of 4/4 Gram-positive species and 2/6 Gram-negative species on inoculated plates compared with control gauze. Residual inhibitory activity of PHMB-impregnated gauze was significantly greater against M. lutea on all days and against S. schleiferi ss. schleiferi on days 1 and 4 compared with control. No bacteria were recovered from inoculated PHMB-impregnated gauze squares placed in sterile wells or from the well floor underneath. More than 9 x 10(5) colony-forming units (CFU) were recovered from inoculated control samples placed in sterile wells and more than 8.4 x 10(4) CFU were recovered from control well floors.

CONCLUSION

PHMB-impregnated gauze dressing, when placed on inoculated agar plates, reduces growth of underlying bacteria, particularly Gram-positive species. Wet-inoculated PHMB-impregnated dressing prevents growth of Gram-positive and Gram-negative bacteria both within and underneath the dressing.

CLINICAL RELEVANCE

PHMB-impregnated dressings may be useful for reducing contamination of underlying wounds by bacterial pathogens.

Treatment of bacterial skin and skin structure infections

Bacterial skin and skin structure infections (SSSIs) are among the most frequently seen infectious entities in the community setting and occasionally in the institutional setting. A wide variety of SSSIs exist, with cellulitis, impetigo and folliculitis being the most common. Most SSSIs are caused by aerobic staphylococci and streptococci, with aerobic Gram-negative bacilli and anaerobes being involved in more complicated infections. Systemic therapy with a variety of beta-lactams, macrolides and lincosamides (clindamycin) have been the cornerstone of SSSI therapy for many years. With the exception of mupirocin, topical therapy occupies a small therapeutic niche. Despite the emergence of antimicrobial resistance among the pathogens most commonly associated with SSSIs (for example, Streptococcus pyogenes and macrolides; Staphylococcus aureus and methicillin, vancomycin, penicillin and mupirocin), few treatment failures have been reported. The newest antimicrobials reviewed herein (linezolid, quinupristin/dalfopristin, gatifloxacin, gemifloxacin and moxifloxacin) are not a significant improvement upon older agents in the treatment of SSSIs. Perhaps this assessment will change if the penetrance of the antimicrobial resistance patterns described above reach a critical threshold and clinical failures become more widespread.

Postrhinoplasty nasal cysts and the use of petroleum-based ointments and nasal packing

Nasal cysts are rare complications of rhinoplasty, and numerous theories exist regarding their cause. The term "paraffinoma" has been used to describe cyst formation observed after topical antibiotic ointment application with nasal packing in the immediate postoperative period. Such complications are rare but may occur because of the inherent properties of the agent used or a lack of meticulous technique (in the placement of incisions and nasal packing). Three cases of postrhinoplasty cysts with a variety of presentations, including incidental intraoperative findings, bilateral medial canthal masses, and a draining dorsal cyst, are described. Although such cysts are uncommon, techniques to prevent these unwanted sequelae should routinely be used, with the judicious application of non-petroleum-based topical antibiotic preparations.

Topical antibacterial agents for wound care: a primer

Although often overlooked, topical antibiotic agents play an important role in dermatology. Their many uses include prophylaxis against cutaneous infections, treatment of minor wounds and infections, and elimination of nasal carriage of Staphylococcus aureus. For these indications, they are advantageous over their systemic counterparts because they deliver a higher concentration of medication directly to the desired area and are less frequently implicated in causing bacterial resistance. The ideal topical antibiotic has a broad spectrum of activity, has persistent antibacterial effects, and has minimal toxicity or incidence of allergy.

Wound healing: a multidisciplinary approach for dermatologists

This article has provided a review of common and some less common approaches to wound healing. Chronic wound healing is one of the more challenging areas of medicine, with a nice balance of the science and art of medicine. An evidence-based, patient-centered approach can be used to effectively improve the care of many difficult to heal ulcers in often frustrated patients. The multidisciplinary wound clinic concept can work to improve the outcomes of patients with leg ulcers.

Effects of topical application of antimicrobials and bandaging on healing and granulation tissue formation in wounds of the distal aspect of the limbs in horses

OBJECTIVE

To determine whether povidone iodine ointment or 2 forms of silver sulfadiazine applied topically to wounds of the distal aspect of the limbs in horses affect the rate of second intention healing and to evaluate the additional influence of bandaging with these antimicrobials on granulation tissue formation.

ANIMALS

6 healthy adult horses.

PROCEDURE

Six standardized 2.5-cm2 skin wounds/horse were distributed between the dorsomedial surfaces of the metacarpi and metatarsi. One of the following 6 treatments was applied to each wound: 1% silver sulfadiazine cream with bandage, 1% silver sulfadiazine slow-release matrix with bandage, 1% silver sulfadiazine slow-release matrix without bandage, povidone-iodine ointment with bandage, untreated control with bandage, and untreated control without bandage. Wound area, granulation tissue area, and perimeter were measured by use of planimetry software applied to digital images. Exuberant granulation tissue was excised when present. Days until healing, rate of healing parameter, rate of contraction, and epithelialization were compared among wound treatment groups.

RESULTS

Healing parameters and mean days to healing did not differ significantly among any of the wound treatment groups. Percentage wound contraction and rate of epithelialization were similar among wound treatments. All bandaged wounds produced exuberant granulation tissue, which was surgically excised; none of the unbandaged wounds produced exuberant granulation tissue.

CONCLUSIONS AND CLINICAL RELEVANCE

When exuberant granulation tissue is removed, rates of epithelialization and wound contraction were not different among wound treatment groups, whether bandaged or unbandaged. Topical application of 1% silver sulfadiazine slow-release matrix on unbandaged wounds induced the same result as medications applied beneath bandages, but without exuberant granulation tissue formation.

A review of antibiotics in dermatology

BACKGROUND

Since the early 1930s when antibiotics were first introduced, they have revolutionized the way physicians treat infections. Skin conditions from acne to leprosy, which were once shunned by society, are now easily treated with oral antibiotics.

OBJECTIVE

Antibiotics are chemicals derived from bacteria and fungi that uniquely have antibacterial action. The most notable example is penicillin, which is derived from a mold. With hundreds of antibiotics available to the practicing physician, improper use of these drugs has become widespread and expensive and has spawned resistant strains. For the dermatologist, antibiotics are vital weapons in the drug armamentarium for treating various skin conditions.

CONCLUSION

This review explores the newest and most common oral, parenteral, and topical antibiotics used in dermatology, their indications, adverse effects, dosage, and spectrum of activity. Furthermore, systemic antibacterial prophylaxis and vaccines pertinent to dermatology are discussed. The penicillins, cephalosporins, tetracyclines, macrolides, fluoroquinolones, sulfonamides, aminoglycosides, lincosamides, folate inhibitors, and a new synthetic class of drugs, the oxazolidinones, are reviewed. These antibiotics are used to treat a variety of organisms.

Postsurgical wound management

Successful outcomes in cutaneous surgery depend on a variety of factors, including preoperative assessment of the patient's health and expectations, intraoperative skill and attention to detail, and managing the postoperative period. Once the procedure is complete, careful selection of dressings, provision of adequate analgesia, judicious management of complications and monitoring the phases of early maturation while providing patient education improve the likelihood of long-term patient and physician satisfaction.

Wound colonization and infection: the role of topical antimicrobials

Infection and bacterial colonization are important factors in compromised wound healing, particularly in chronic wounds. The current "best practice" for controlling these factors is still unclear. Systemic antibiotics are generally accepted as being the preferred choice for treating infection, provided that ischaemia does not interfere. However, their widespread systemic and topical use is leading to the emergence of resistant bacterial strains such as methicillin-resistant Staphylococcus aureus. Colonization of wounds presents a double problem: possible delayed healing if out of balance with the immune system; and as a source for cross-infection. Managing colonization is not yet defined in best practice. The judicious use of dressings, notably those containing certain antiseptic agents, can be valuable in infection control and in promoting healing. This review states the case for taking the antiseptic route as part of the concerted approach to local wound management and infection control.