Methicillin-resistant Staphylococcus aureus (MRSA) skin infections are increasingly common. Automated microbiology systems are now available to detect MRSA and to determine antibiotic resistance patterns. Abscesses should be drained and antibiotics administered, with systemic antibiotics used to manage more severe infections. Until sensitivities are known and depending on local resistance rates, clindamycin is an option for empiric management of stable patients without bacteremia. For patients who are more ill, linezolid and vancomycin are alternatives, the latter being first-line treatment for children hospitalized with MRSA skin infections. Drug resistance also occurs in head lice management. Although topical permethrin is still the first-line drug management, its effectiveness has decreased due to permethrin-resistant strains. Patients who do not benefit from 2 applications of permethrin can be treated with topical malathion or topical ivermectin. Though not approved by the Food and Drug Administration (FDA) for treating head lice, oral ivermectin is sometimes used for difficult-to-treat cases. Permethrin is also the first-line management for scabies, though there is a concern that permethrin-resistant scabies may soon occur. For patients with scabies who do not benefit from topical treatment, oral ivermectin is recommended by the Centers for Disease Control and Prevention, although it is not approved by the FDA for this purpose.

OBJECTIVES:

The main purpose of this study is the detection of amoxicillin and clindamycin concentrations in teeth.

MATERIALS AND METHODS:

Eleven patients received 2 g of amoxicillin, and 11 patients received 600 mg of clindamycin in a single dose of oral medication at least 60 min prior to tooth extraction due to systemic diseases. The concentrations were determined in crowns and roots separately using liquid chromatography-tandem mass spectrometry (LC-MS-MS).

RESULTS:

Amoxicillin (13 samples) and clindamycin (12 samples) were detected in the samples of the root and crown preparations of the extracted teeth. The mean concentration of amoxicillin was 0.502 μg/g in the roots and 0.171 μg/g in the crowns. The mean concentration of clindamycin was 0.270 μg/g in the roots and 0.064 μg/g in the crowns.

CONCLUSIONS:

A single dose of oral amoxicillin and clindamycin leads to concentrations of both antibiotics in teeth which exceed the minimal inhibition concentration of some oral bacteria.

CLINICAL RELEVANCE:

The proof of antibacterial activity in dental hard tissue after oral single-dose application is new. The antimicrobial effect of amoxicillin and clindamycin concentrations in roots of teeth may be of clinical relevance to bacterial reinfection from dentinal tubules.

A 4-year-old boy presented with unilateral endophthalmitis and echography revealed an abscess in the vitreous cavity. A pars plana vitrectomy with intravitreal antibiotic injections was performed with a presumed diagnosis of endophthalmitis; however, the patient returned after 10 days with fibrin reaction in the anterior chamber, iris nodules and cataract. The vitreous sample from the vitrectomy showed Toxoplasma gondii parasite, so he was treated with intravitreal clindamycin and lensectomy. The postoperative fundus examination revealed multifocal white patches with calcified deposits and cytology proved the diagnosis of retinoblastoma. Enucleation was performed in addition to systemic chemotherapy. To our knowledge, this is the first reported case of the coexistence of retinoblastoma and ocular toxoplasmosis.

Rosacea is a common, chronic, and poorly understood dermatological condition characterized by an inflammatory component composed of papules and pustules and a vascular component composed of flushing and erythema. Current treatment options include topical, systemic, and light-based methods, each of which focuses on either the inflammatory or the vascular component. Retinoids are not routinely indicated as treatment because of the common conception that they would be too inflammatory for the sensitive rosacea patient. However, photodamage may play a role in rosacea and tretinoin is well-known to repair photodamage. Thirty rosacea subjects were enrolled to assess their response to the use of clindamycin phosphate 1.2% and tretinoin 0.025% gel (ZIANA; Medicis Pharmaceutical Corporation, Scottsdale, AZ) for a period of 12 weeks. The results showed a dramatic decrease in pustules and papules without any significant inflammation or overall intolerance. No improvement in facial redness was achieved. Based on our results, more investigation of topical retinoids for rosacea treatment is prudent.

In venous ulcers, the presence of Staphylococcus aureus and coagulase-negative staphylococcus resistance phenotypes can aggravate and limit the choices for treatment.Staphylococcus isolated from 69 patients (98 ulcers) between October of 2009 and October of 2010 were tested. The macrolide, lincosamide, streptogramin B (MLS B) group resistance phenotype detection was performed using the D-test. Isolates resistant to cefoxitin and/or oxacillin (disk-diffusion) were subjected to the confirmatory test to detect minimum inhibitory concentration (MIC), using oxacillin strips (E-test®).The prevalence of S. aureus was 83%, and 15% of coagulase-negative staphylococcus (CoNS). In addition were detected 28% of methicillin-resistant Staphylococcus aureus (MRSA) and 47% of methicillin-resistant coagulase-negative staphylococcus (MRCoNS). Among the S. aureus, 69.6% were resistant to erythromycin, 69.6% to clindamycin, 69.6% to gentamicin, and 100% to ciprofloxacin. Considering the MRSA, 74% were highly resistant to oxacillin, MIC ≥ 256µg/mL, and the MLS Bc constitutive resistance predominated in 65.2%. Among the 20 isolates sensitive to clindamycin, 12 presented an inducible MLS B phenotype. Of the MRCoNS, 71.4%were resistant to erythromycin, ciprofloxacin and gentamicin. Considering the isolates positive for β-lactamases, the MIC breakpoint was between 0.5 and 2µg/mL.The results point to a high occurrence of multi-drug resistant bacteria in venous ulcers in primary healthcare patients, thus evidencing the need for preventive measures to avoid outbreaks caused by multi-drug resistant pathogens, and the importance of healthcare professionals being able to identifying colonized versus infected venous ulcers as an essential criteria to implementing systemic antibacterial therapy.

Fox-Fordyce disease (FFD) is a rare inflammatory disorder that affects the apocrine sweat glands. Clinically, lesions are equidistant, smooth, uniform, firm, folliculocentric papules, which can range in color from flesh-colored to red-brown to slightly yellow. Whereas the axillae are most commonly involved, FFD also can involve the anogenital and periareolar areas, lips, umbilicus, sternum, perineum, and upper medial aspects of the thighs. The underlying etiology of FFD remains unclear although epidemiologic data support a hormonal component because women are more commonly affected than men. Moreover, symptoms initially present after the onset of puberty, flare perimenstrually, and often resolve during pregnancy and after menopause. Histopathologic findings include the obstruction of the apocrine duct by a hyperkeratotic plug in the follicular infundibulum, which is believed to represent the primary pathophysiologic process; subsequent ductal rupture and resulting inflammatory response produce the typical clinical picture. Treatment of FFD is difficult because no one agent has proven particularly effective. Topical and interlesional glucocorticoids are often considered the first-line pharmacologic agents, although use is often limited by concerns for atrophy. Other agents that have shown some success include topical and systemic retinoids, topical clindamycin, topical pimecrolimus cream, benzoyl peroxide, and oral contraceptives. For medication-refractory cases, mechanical destruction or removal of the apocrine glands has been efficacious in small case series.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) frequently causes skin and soft tissue infections, including impetigo, cellulitis, folliculitis, and infected wounds and ulcers. Uncomplicated CA-MRSA skin infections are typically managed in an outpatient setting with oral and topical antibiotics and/or incision and drainage, whereas complicated skin infections often require hospitalization, intravenous antibiotics, and sometimes surgery. The aim of this study was to develop a mouse model of CA-MRSA wound infection to compare the efficacy of commonly used systemic and topical antibiotics. A bioluminescent USA300 CA-MRSA strain was inoculated into full-thickness scalpel wounds on the backs of mice and digital photography/image analysis and in vivo bioluminescence imaging were used to measure wound healing and the bacterial burden. Subcutaneous vancomycin, daptomycin, and linezolid similarly reduced the lesion sizes and bacterial burden. Oral linezolid, clindamycin, and doxycycline all decreased the lesion sizes and bacterial burden. Oral trimethoprim-sulfamethoxazole decreased the bacterial burden but did not decrease the lesion size. Topical mupirocin and retapamulin ointments both reduced the bacterial burden. However, the petrolatum vehicle ointment for retapamulin, but not the polyethylene glycol vehicle ointment for mupirocin, promoted wound healing and initially increased the bacterial burden. Finally, in type 2 diabetic mice, subcutaneous linezolid and daptomycin had the most rapid therapeutic effect compared with vancomycin. Taken together, this mouse model of CA-MRSA wound infection, which utilizes in vivo bioluminescence imaging to monitor the bacterial burden, represents an alternative method to evaluate the preclinical in vivo efficacy of systemic and topical antimicrobial agents.

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is a rare, complex, idiosyncratic drug reaction that can be fatal. Systemic symptoms include lymphadenopathy, hepatic failure, and possibly renal failure. The syndrome has been primarily associated with anticonvulsants, whereas antimicrobials are less commonly associated. We describe a 63-year-old woman who initially presented with rash and acute kidney injury secondary to treatment with clindamycin for a methicillin-susceptible Staphylococcus aureus prosthetic hip infection. Her rash progressed to desquamation of over 90% of her body surface area. Her renal function progressively declined during her hospital stay, and continuous renal replacement therapy was started. Peripheral eosinophilia was present, and urine studies were consistent with intrinsic renal failure. The patient also developed pancreatitis, hepatic failure with elevated liver enzyme levels and coagulopathy, respiratory failure necessitating mechanical ventilation, and hypotension. After a 16-day hospitalization, life-sustaining measures were withdrawn, and the patient died. Use of a cutaneous adverse drug reaction scale indicated that clindamycin was the definite cause of this patient's DRESS syndrome. To our knowledge, this is the first case report of fatal clindamycin-induced DRESS syndrome and only the second case report of DRESS attributable to clindamycin therapy. Although commonly linked with anticonvulsants, clinicians should consider the possibility of this reaction with antimicrobials, including clindamycin.

We introduced a long-term care facility (LTCF) infectious disease (ID) consultation service (LID service) that provides on-site consultations to residents of a Veterans Affairs (VA) LTCF. We determined the impact of the LID service on antimicrobial use and Clostridium difficile infections at the LTCF.A 160-bed VA LTCF.Systemic antimicrobial use and positive C. difficile tests at the LTCF were compared for the 36 months before and the 18 months after the initiation of the ID consultation service through segmented regression analysis of an interrupted time series.Relative to that in the preintervention period, total systemic antibiotic administration decreased by 30% (P<.001), with significant reductions in both oral (32%; P<.001) and intravenous (25%; P=.008) agents. The greatest reductions were seen for tetracyclines (64%; P<.001), clindamycin (61%; P<.001), sulfamethoxazole/trimethoprim (38%; P<.001), fluoroquinolones (38%; P<.001), and β-lactam/β-lactamase inhibitor combinations (28%; P<.001). The rate of positive C. difficile tests at the LTCF declined in the postintervention period relative to preintervention rates (P=.04).Implementation of an LTCF ID service led to a significant reduction in total antimicrobial use. Bringing providers with ID expertise to the LTCF represents a new and effective means to achieve antimicrobial stewardship.

The purpose of this study is to report a case of methicillin-resistant Staphylococcus aureus (MRSA) keratitis in a dog. A 7-year-old intact male American cocker spaniel that had undergone removal of a nictitating gland was referred for severe ulcerative keratitis. Slit-lamp examination showed swelling of the eyelid, mucopurulent discharge, conjunctival injection and chemosis, diffuse corneal edema and opacity, and a deep ulcer in central cornea. Gram staining of discharge from the eye demonstrated Gram-positive cocci. Despite topical ofloxacin, oxytetracycline and polymyxin B ophthalmic solution and intravenous cefazolin, there was no improvement. Cultures revealed MRSA that was sensitive only to chloramphenicol, vancomycin, lincomycin, and clindamycin. The antibiotic regimen was changed to topical and systemic chloramphenicol. After 9 days of treatment, although inflammation started to be resolved, the dog developed nonregenerative anemia. The antimicrobial regimen was changed again to topical and systemic vancomycin. Inflammation continued to improve over the next week. MRSA should be considered a potential organism in infectious keratitis, especially when general antibiotics are not effective. Although topical and systemic chloramphenicol and/or vancomycin are effective for treating MRSA keratitis, vancomycin should only be used when culture and susceptibility results indicate it is appropriate and no other options are available. To our knowledge, this is the first detailed case report of MRSA keratitis in a dog.