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Concept: Abscess

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BACKGROUND: The initial pathology in hidradenitis suppurativa / acne inversa (HS) takes place in the folliculopilosebaceous unit (FPSU) and its surrounding tissue. The process involves follicular hyperkeratosis, inflammation and perifolliculitis. Identification of the exact origin of inflammation may shed new light on the pathogenesis and aetiology of the disease. OBJECTIVES: To study the morphology of the basement membrane zone (BMZ) in patients with HS. METHODS: Operative specimens obtained from 20 patients diagnosed with HS were cut stepwise. Within each specimen focus was set on heavily involved HS regions (centre) and clinically uninvolved regions (border). All (n=65) were stained with Periodic Acid Schiff (PAS) to visualise the epithelial support structures (basement membrane zone, BMZ) of the FPSU, the sinus tracts (ST) and the interfollicular epidermis (BM). The intensity of BMZ PAS staining was graded 0-4+. RESULTS: Compared to axillary skin of human controls the sebofollicular junction in HS patients was found to be almost devoid of PAS positive material (0/1+) in both the border and centre lesions of HS, whereas STs and BMs showed uniformly 2-3+ positivity irrespective of inflammation present. The distribution of inflammatory cells around the sebofollicular junction occurred predominantly in areas of BMZ thinning CONCLUSIONS: BMZ PAS-positivity of clinically uninvolved FPSUs of HS patients appears to be wispy or missing entirely. It is speculated that this may explain the apparent fragility of the sebofollicular junction. There is an increased concentration of inflammatory cells adjacent to these areas, whilst inflammatory cells are scarce in areas where the PAS material is intact. It is hypothesised that the PAS gap identifies areas susceptible to leakage, trauma and rupture, leading to release of materials that trigger inflammatory mediators, and the seeding of the dermis with free-living stem cells generating benign but invasive epithelialised sinuses, spreading horizontally in the dermis.

Concepts: Inflammation, Pathology, Epithelium, Skin, Epidermis, Fistula, Hidradenitis suppurativa, Abscess

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BACKGROUND: It was the aim of this prospective study to analyze both the feasibility and preliminary results of video-assisted anal fistula treatment (VAAFT) combined with advancement flap repair for complex fistulas in Crohn’s disease. METHODS: All patients with perianal Crohn’s disease suffering from complex fistulas who underwent definitive surgery using VAAFT combined with advancement flap repair were prospectively enrolled in the study. Only complex fistulas with concurrent stable disease and without any evidence of severe inflammatory activity or perianal sepsis were treated using the VAAFT technique. Patients with Crohn’s proctitis or prior proctectomy were not candidates for the procedure. VAAFT was performed by using the VAAFT equipment (Karl Storz, Tuttlingen, Germany). Key steps included visualization of the fistula tract and/or side tracts using the fistuloscope and correct localization of the internal fistula opening under direct vision with irrigation. Diagnostic fistuloscopy was followed by advancement flap repair. In addition to feasibility, primary end points included detection of side tracts, success and continence status (assessed by the Cleveland Clinic Incontinence Score). Success was defined as closure of both internal and external openings, absence of drainage without further intervention and absence of abscess formation. Follow-up information was derived from clinical examination 3, 6 and 9 months postoperatively. RESULTS: Within a 3-month observation period (September to November 2011), VAAFT was attempted in 13 patients with Crohn’s associated complex fistulas. The completion rate was 85 % (11/13). In these 11 patients (median age 34 years, 64 % females), complex fistulas were transsphincteric (8), suprasphincteric (2) and recto-vaginal (1). Forty-six percent (5/11) had concomitant therapy with biologic drugs. In 36 % (4/11), VAAFT was performed with fecal diversion. Median duration of surgery was 22 (range 18-42) minutes. Using VAAFT, additional side tracts not detected preoperatively could be identified in 64 % (7/11). No morbidity occurred. After a mean follow-up of 9 months, the success rate was 82 % (9/11). No deterioration of continence was documented (Cleveland Clinic Incontinence Score 2.4 vs. 1.6, p > 0.05). CONCLUSION: Preliminary results of the addition of the VAAFT technique to advancement flap repair in Crohn’s fistulas demonstrate that this leads to a high identification rate of occult side tracts with encouraging short-term healing rates. Moreover, a completion rate of 85 % seems promising.

Concepts: Ulcerative colitis, Crohn's disease, Fistula, Fecal incontinence, Anal fistula, Abscess, Cleveland, Cleveland Clinic

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We present a case of a patient with Lemierre’s syndrome caused by Fusobacterium necrophorum who developed a right frontal lobe brain abscess. We summarise the epidemiology, microbiology, pathogenesis, clinical presentation, diagnosis, complications, therapy, and outcomes of Lemierre’s syndrome. F necrophorum is most commonly associated with Lemierre’s syndrome: a septic thrombophlebitis of the internal jugular vein. Patients usually present with an exudative tonsillitis, sore throat, dysphagia, and unilateral neck pain. Diagnosis of septic thrombophlebitis is best confirmed by obtaining a CT scan of the neck with contrast. Complications of the disease include bacteraemia with septic abscesses to the lungs, joints, liver, peritoneum, kidneys, and brain. Treatment should include a prolonged course of intravenous beta-lactam antibiotic plus metronidazole.

Concepts: Liver, Internal jugular vein, Jugular vein, Frontal lobe, Common facial vein, Neck, Abscess, Fusobacterium necrophorum

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We present an unusual case of nontyphoidal Salmonella causing an epidural abscess and vertebral osteomyelitis in a severely immunocompromised patient with AIDS as well as a review of the literature. Salmonella vertebral osteomyelitis is exceptionally rare, and this is the first case report in a patient with AIDS.

Concepts: Immune system, Inflammation, Opportunistic infection, Staphylococcus aureus, Pus, Abscess, Salmonellosis, Ubi pus, ibi evacua

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It has been claimed that amoebic molecules such as amoebapore, galactose/N-acetyl galactosamine inhibitable lectin, and cysteine proteases are responsible for host tissue destruction and are present in both pathogenic E. histolytica and non-pathogenic E. dispar. Some reports have provided evidence that after infection with E. dispar, pathological changes may occur in some humans. The aim of this study was to evaluate E. dispar pathogenicity by comparing it to the pathogenicity of E. histolytica through liver abscesses induced in hamsters. Syrian golden hamsters were challenged by intrahepatic inoculation with the 03C E. dispar strain or with two strains of E. histolytica (HM1:IMSS and EGG) to compare their virulence grades. As control groups, we used bacterial flora and Pavlova’s modified medium. Lesions were verified at 1, 3 and 6 days after inoculation. Multiplex Polymerase Chain Reaction was performed to characterize each strain using EdP1/EdP2 and EhP1/EhP2 primers. The EGG and HM1:IMSS E. histolytica strains and 03C E. dispar were able to cause liver lesions. The EGG strain caused extensive hepatic abscesses, and trophozoites were found in the lesions throughout the three periods of study. The HM1:IMSS strain caused smaller abscesses when compared to EGG lesions; however, trophozoites were observed at 1 and 3 days after inoculation. The 03C E. dispar strain caused intermediate abscesses when compared to the others; trophozoites were observed in all periods analyzed. The EGG strain caused progressive evolution of the injury, which differed from the HM1:IMSS and 03C strains. These results strongly suggest that the 03C E. dispar strain is pathogenic in the experimental hamster model. Additional studies are necessary to identify potential factors that regulate the manifestation of virulence of this strain and others.

Concepts: DNA, Parasites, Causality, Entamoeba histolytica, Abscess, Amoebozoa, Entamoeba, Liver abscess

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Background U.S. emergency department visits for cutaneous abscess have increased with the emergence of methicillin-resistant Staphylococcus aureus (MRSA). The role of antibiotics for patients with a drained abscess is unclear. Methods We conducted a randomized trial at five U.S. emergency departments to determine whether trimethoprim-sulfamethoxazole (at doses of 320 mg and 1600 mg, respectively, twice daily, for 7 days) would be superior to placebo in outpatients older than 12 years of age who had an uncomplicated abscess that was being treated with drainage. The primary outcome was clinical cure of the abscess, assessed 7 to 14 days after the end of the treatment period. Results The median age of the participants was 35 years (range, 14 to 73); 45.3% of the participants had wound cultures that were positive for MRSA. In the modified intention-to-treat population, clinical cure of the abscess occurred in 507 of 630 participants (80.5%) in the trimethoprim-sulfamethoxazole group versus 454 of 617 participants (73.6%) in the placebo group (difference, 6.9 percentage points; 95% confidence interval [CI], 2.1 to 11.7; P=0.005). In the per-protocol population, clinical cure occurred in 487 of 524 participants (92.9%) in the trimethoprim-sulfamethoxazole group versus 457 of 533 participants (85.7%) in the placebo group (difference, 7.2 percentage points; 95% CI, 3.2 to 11.2; P<0.001). Trimethoprim-sulfamethoxazole was superior to placebo with respect to most secondary outcomes in the per-protocol population, resulting in lower rates of subsequent surgical drainage procedures (3.4% vs. 8.6%; difference, -5.2 percentage points; 95% CI, -8.2 to -2.2), skin infections at new sites (3.1% vs. 10.3%; difference, -7.2 percentage points; 95% CI, -10.4 to -4.1), and infections in household members (1.7% vs. 4.1%; difference, -2.4 percentage points; 95% CI, -4.6 to -0.2) 7 to 14 days after the treatment period. Trimethoprim-sulfamethoxazole was associated with slightly more gastrointestinal side effects (mostly mild) than placebo. At 7 to 14 days after the treatment period, invasive infections had developed in 2 of 524 participants (0.4%) in the trimethoprim-sulfamethoxazole group and in 2 of 533 participants (0.4%) in the placebo group; at 42 to 56 days after the treatment period, an invasive infection had developed in 1 participant (0.2%) in the trimethoprim-sulfamethoxazole group. Conclusions In settings in which MRSA was prevalent, trimethoprim-sulfamethoxazole treatment resulted in a higher cure rate among patients with a drained cutaneous abscess than placebo. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT00729937 .).

Concepts: Inflammation, Disease, Staphylococcus aureus, Antibiotic resistance, Methicillin-resistant Staphylococcus aureus, Linezolid, Pus, Abscess

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A 13-year-old boy presented with a 9-month history of episodic unilateral swelling of the face and oral pain. He reported having loose, nonbloody stools. Granulomatous inflammation consistent with Crohn’s disease was found on histopathological examination.

Concepts: Inflammation, Histopathology, Crohn's disease, Inflammatory bowel disease, Face, Granuloma, Abscess

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Cutaneous abscess infections are difficult to treat with current therapies and alternatives to conventional antibiotics are needed. Understanding the regulatory mechanisms that govern abscess pathology should reveal therapeutic interventions for these recalcitrant infections. Here we demonstrated that the stringent stress response employed by bacteria to cope and adapt to environmental stressors was essential for the formation of lesions, but not bacterial growth, in a methicillin resistant Staphylococcus aureus (MRSA) cutaneous abscess mouse model. To pharmacologically confirm the role of the stringent response in abscess formation, a cationic peptide that causes rapid degradation of the stringent response mediator, guanosine tetraphosphate (ppGpp), was employed. The therapeutic application of this peptide strongly inhibited lesion formation in mice infected with Gram-positive MRSA and Gram-negative Pseudomonas aeruginosa. Overall, we provide insights into the mechanisms governing abscess formation and a paradigm for treating multidrug resistant cutaneous abscesses.

Concepts: Bacteria, Microbiology, Staphylococcus aureus, Antibiotic resistance, Methicillin-resistant Staphylococcus aureus, Penicillin, Pus, Abscess

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Background Skin and skin-structure infections are common in ambulatory settings. However, the efficacy of various antibiotic regimens in the era of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) is unclear. Methods We enrolled outpatients with uncomplicated skin infections who had cellulitis, abscesses larger than 5 cm in diameter (smaller for younger children), or both. Patients were enrolled at four study sites. All abscesses underwent incision and drainage. Patients were randomly assigned in a 1:1 ratio to receive either clindamycin or trimethoprim-sulfamethoxazole (TMP-SMX) for 10 days. Patients and investigators were unaware of the treatment assignments and microbiologic test results. The primary outcome was clinical cure 7 to 10 days after the end of treatment. Results A total of 524 patients were enrolled (264 in the clindamycin group and 260 in the TMP-SMX group), including 155 children (29.6%). One hundred sixty patients (30.5%) had an abscess, 280 (53.4%) had cellulitis, and 82 (15.6%) had mixed infection, defined as at least one abscess lesion and one cellulitis lesion. S. aureus was isolated from the lesions of 217 patients (41.4%); the isolates in 167 (77.0%) of these patients were MRSA. The proportion of patients cured was similar in the two treatment groups in the intention-to-treat population (80.3% in the clindamycin group and 77.7% in the TMP-SMX group; difference, -2.6 percentage points; 95% confidence interval [CI], -10.2 to 4.9; P=0.52) and in the populations of patients who could be evaluated (466 patients; 89.5% in the clindamycin group and 88.2% in the TMP-SMX group; difference, -1.2 percentage points; 95% CI, -7.6 to 5.1; P=0.77). Cure rates did not differ significantly between the two treatments in the subgroups of children, adults, and patients with abscess versus cellulitis. The proportion of patients with adverse events was similar in the two groups. Conclusions We found no significant difference between clindamycin and TMP-SMX, with respect to either efficacy or side-effect profile, for the treatment of uncomplicated skin infections, including both cellulitis and abscesses. (Funded by the National Institute of Allergy and Infectious Diseases and the National Center for Advancing Translational Sciences, National Institutes of Health; ClinicalTrials.gov number, NCT00730028 .).

Concepts: Staphylococcus aureus, Infection, Antibiotic resistance, Methicillin-resistant Staphylococcus aureus, Linezolid, Clindamycin, Pus, Abscess

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Skin and soft tissue infections (SSTIs) are common in the general population, with increased prevalence among military trainees. Previous research has revealed numerous nasal microbial signatures that correlate with SSTI development and Staphylococcus aureus colonization. Thus, we hypothesized that the ecology of the inguinal, oropharynx, and perianal regions may also be altered in response to SSTI and/or S. aureus colonization. We collected body site samples from 46 military trainees with purulent abscess (SSTI group) as well as from 66 asymptomatic controls (non-SSTI group). We also collected abscess cavity samples to assess the microbial composition of these infections. Samples were analyzed by culture, and the microbial communities were characterized by high-throughput sequencing. We found that the nasal, inguinal, and perianal regions were similar in microbial composition and significantly differed from the oropharynx. We also observed differences in Anaerococcus and Streptococcus abundance between the SSTI and non-SSTI groups for the nasal and oropharyngeal regions, respectively. Furthermore, we detected community membership differences between the SSTI and non-SSTI groups for the nasal and inguinal sites. Compared to that of the other regions, the microbial compositions of the nares of S. aureus carriers and noncarriers were dramatically different; we noted an inverse correlation between the presence of Corynebacterium and the presence of Staphylococcus in the nares. This correlation was also observed for the inguinal region. Culture analysis revealed elevated methicillin-resistant S. aureus (MRSA) colonization levels for the SSTI group in the nasal and inguinal body sites. Together, these data suggest significant microbial variability in patients with SSTI as well as between S. aureus carriers and noncarriers. IMPORTANCE While it is evident that nasal colonization with S. aureus increases the likelihood of SSTI, there is a significant lack of information regarding the contribution of extranasal colonization to the overall risk of a subsequent SSTI. Furthermore, the impact of S. aureus colonization on bacterial community composition outside the nasal microbiota is unclear. Thus, this report represents the first investigation that utilized both culture and high-throughput sequencing techniques to analyze microbial dysbiosis at multiple body sites of healthy and diseased/colonized individuals. The results described here may be useful in the design of future methodologies to treat and prevent SSTIs.

Concepts: Scientific method, Bacteria, Microbiology, Staphylococcus aureus, Staphylococcus, Skin, Pus, Abscess