Bacteria isolated from skin and soft tissue lesions

Immediate effect of pulsed high-intensity neodymium-doped yttrium aluminum garnet (Nd: YAG) laser on staphylococcus aureus and pseudomonas aeruginosa growth: an experimental study

[Purpose] The aim of this study was to evaluate the effect of pulsed high intensity neodymium-doped yttrium aluminum garnet (Nd: YAG) laser on staphylococcus aureus (S. aureus) and pseudomonas aeruginosa (P. aeruginosa) bacterial growth, which cause many health problems and establish which doses are effective in bacterial inhibition. [Materials and Methods] Five samples of S. aureus and five samples of P. aeruginosa were prepared in the microbiology lab, one used as control sample and the other 4 samples acted as experimental samples. The experimental samples received pulsed high intensity Nd: YAG laser with a total dose of 500, 600, 700 and 800 joules. The primary measures are colony count and the percentage decrease in colony count, the colony count was assessed at baseline and after 24 h of laser application. [Result] There was significant decrease in colony count and the percentage decrease in colony count after pulsed high intensity Nd: YAG laser application in all experimental samples of S. aureus and P. aeruginosa after 24 h of application for all doses (500, 600, 700 and 800 j) as compared with the control sample, with the most effect in higher doses of pulsed high intensity Nd: YAG laser than lower doses in both types of bacteria. [Conclusion] pulsed high intensity Nd: YAG laser was found to be an effective modality for inhibition of S. aureus and P. aeruginosa growth after a single application.

Efficacy of Dalbavancin and Telavancin in the Treatment of Acute Bacterial Skin and Skin Structure Infections

Objectives

Two glycopeptide analogues, such as dalbavancin and telavancin, with improved pharmacokinetic/pharmacodynamic parameters have been developed. These two glycopeptide analogues are approved by Food and Drug Administration (FDA) for treatment of various Gram-positive bacterial skin infections.

Materials and methods

We have conducted an open labelled prospective randomized study to compare the efficacy of these two drugs. A total of 200 patients diagnosed with acute bacterial skin and skin structure infections (ABSSSI) were recruited for the study. They were randomized to receive either a single dose of dalbavancin 1500 mg i.v (Group I) or telavancin 10 mg/kg intravenously (i.v.) every 24 hours for six days (Group II). The skin infection rating score (SIRS) was calculated on Day 0 for all patients at the time of diagnosis. Signs and symptoms of the lesions were assessed based on the following factors: blistering, exudate/pus, erythema/inflammation and itching/pain. Each factor was classified as one of the following: absent - 0, minimal - 1, moderate - 2 and severe - 3.

Results

Clinically successful treatment was defined as complete resolution of clinically meaningful signs and symptoms of infection, including SIRS score of 0. The outcome measure was the percentage of patients with SIRS score of 0 on day 7 (clinical success). The third most common diagnosis at baseline was impetigo (13% in both groups). Patients who received dalbavancin had a higher clinical success rate than those receiving telavancin.

Conclusion

Findings of the present study show that single i.v dose of dalbavancin is better than telavancin repeated doses in treatment of ABSSSI.

[Microbiology of pressure and vascular ulcer infections]

INTRODUCTION

Pressure ulcer (PU) infection is a significant clinical problem in many elderly patients.

MATERIAL AND METHODS

To determine the microbiology of PU and vascular ulcer (VU) infections by conducting a cross-sectional study of outpatients treated in a chronic wounds unit over an 18 month period.

RESULTS

Sixty six patients with PU infection and 159 patients with an infected VU were identified. The PUs were located below the knee in 36 patients (52%). Patients with pressure ulcers had a higher proportion of institutionalization, cognitive impairment, inability to walk, and sphincter incontinence. There was a greater number of infections caused by Enterobacteriaceae (52%, P=.002) and fewer S. aureus infections (24%, P<.001) in patients with a PU compared to those with those with a VU. Forty-one percent of S. aureus strains isolated in all the patients were resistant to methicillin (MRSA). The proportion of Enterobacteriaceae infections was similar in patients with infection of pelvic girdle PU and in those located below the knee.

CONCLUSIONS

PU patients suffer a higher rate of infection by enterobacteria. The most common pathogen in UV infections is S. aureus. The proportion of MRSA infection in patients with chronic wounds is high. The microbiology of the infection in the pelvic girdle PU is similar to those located below the knee.

In vitro bactericidal effects of 625, 525, and 425 nm wavelength (red, green, and blue) light-emitting diode irradiation

OBJECTIVE

The purpose of this study was to evaluate the relationship of 625, 525, and 425 nm wavelengths, providing average power output and effects on three common pathogenic bacteria.

BACKGROUND DATA

Ultraviolet (UV) light kills bacteria, but the bactericidal effects of UV may not be unique, as 425 nm produces a similar effect. The bactericidal effects of light-emitting diode (LED) wavelengths such as 625 and 525 nm have not been described. Before conducting clinical trials, the appropriate wavelength with reasonable dose and exposure time should be established.

MATERIALS AND METHODS

The bactericidal effects of 625, 525, and 425 nm wavelength LED irradiation were investigated in vitro for the anaerobic bacterium Porphyromonas gingivalis and two aerobes (Staphylococcus aureus and Escherichia coli DH5α). Average power output was 6 mW/cm(2) for 1 h. The bacteria were exposed to LED irradiation for 1, 2, 4, and 8 h (21.6, 43.2, 86.4, and 172.8 J/cm(2), respectively). LED irradiation was performed during growth on agar and in broth. Control bacteria were incubated without LED irradiation. Bacterial growth was expressed in colony-forming units (CFU) and at an optical density at 600 nm in agar and broth.

RESULTS

The bactericidal effect of LED phototherapy depended upon wavelength, power density, bacterial viable number, and bacteria species. The bactericidal effect of 425 and 525 nm irradiation varied depending upon the bacterial inoculation, compared with unirradiated samples and samples irradiated with red light. Especially, P. gingivalis and E. coli DH5α were killed by 425 nm, and S. aureus growth was inhibited by 525 nm. However, the wavelength of 625 nm was not bactericidal for P. gingivalis, E. coli DH5α, or S. aureus.

CONCLUSIONS

Irradiation at 625 nm light was not bactericidal to S. aureus, E. coli, and P. gingivalis, whereas wavelengths of 425 and 525 nm had bactericidal effects. S. aureus was also killed at 525 nm.

Proteolytic activity by multiple bacterial species isolated from chronic venous leg ulcers degrades matrix substrates

BACKGROUND

A major feature of chronic wounds is the loss of tissue, with the exposure of dermal components preventing primary closure and leading to bacterial colonization. Bacterial colonization has been proposed as one of the common underlying pathologies present in chronic wounds. The objective of this exploratory study was to identify bacteria cultured from chronic venous leg ulcers and test for proteolytic activity that degrades matrix substrates.

METHOD

Bacteria were isolated, cultured, and identified from six subjects (average age = 62.8 years) over 2-10 months under an approved protocol using swabs and microbiological culture media. Proteolytic activity against (a) gelatin, (b) an elastin substrate, and (c) a serine/trypsin-sensitive substrate was determined using a colorimetric plate assay with an ELISA plate reader and zymography.

RESULTS

We identified 13 bacteria that expressed proteolytic activity against one or more of the tested substrates. Of these, six were Gram-positive (Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Streptococcus agalactiae, Corynebacterium, and Streptococcus bovis) and seven were Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Morganella morganii, Klebsiella pneumoniae, Bacteroides fragilis, and Serratia marcescens) organisms. Two of these, S. aureus and P. aeruginosa, are recognized wound pathogens.

CONCLUSIONS

Multiple bacteria species isolated from colonized venous leg ulcers have the capacity to secrete proteases capable of degrading components of the extracellular matrix important for wound healing. Matrix degradation by bacteria may contribute to delays in tissue deposition and repair, suggesting that treatment of chronic wounds should include appropriate management of colonizing bacteria.

Efeitos da terapia fotodinâmica e de uma única aplicação de laser de baixa potência em bactérias in vitro

O laser de baixa potência vem sendo usado para acelerar a cicatrização em úlceras de pressão devido a seus efeitos cicatrizante, antiinflamatório, antiedematoso e analgésico. No entanto, não há consenso quanto a seu efeito em úlceras infectadas. O objetivo deste estudo foi verificar o efeito bactericida da laserterapia e da terapia fotodinâmica (TFD) com laser de baixa potência, InGaP, 670 nm, em doses de 2, 4 e 6 J/cm², em bactérias gram-positivas e gram-negativas in vitro. Foram preparadas 32 placas de Petri com bactérias, 16 com Pseudomonas aeruginosa e 16 com Staphilococcus aureus. Aleatoriamente dividiu-se cada grupo em oito subgrupos (duas placas cada): três subgrupos tratados só com laserterapia, em doses de 2 J/cm², 4 J/cm² e 6 J/cm²; três subgrupos tratados com TFD, em doses de 2 J/cm², 4 J/cm² e 6 J/cm²; um tratado apenas com fotossensibilizante (azul de metileno a 0,1 µg/ml); e um subgrupo não tratado (controle). Os subgrupos laser e TFD foram irradiados uma única vez e incubados por 24 horas. Os outros dois subgrupos não receberam irradiação. As culturas foram analisadas visualmente para verificação ou não do halo de inibição. Em todos os subgrupos, de ambas as bactérias, não foi observado qualquer halo de inibição nem de crescimento. Conclui-se que a terapia a laser e a fotodinâmica de baixa potência (InGaP, 670 nm) não produziram efeitos bactericidas e/ou bacteriostáticos, tampouco tendo havido efeito bioestimulante sobre as bactérias.

Safety and efficacy of tigecycline in treatment of skin and skin structure infections: results of a double-blind phase 3 comparison study with vancomycin-aztreonam

In a randomized, double-blind, controlled trial, 546 patients with complicated skin and skin structure infections received tigecycline 100 mg/day (a 100-mg initial dose and then 50 mg intravenously twice daily) or the combination of vancomycin 2 g/day (1 g intravenously twice daily) and aztreonam 4 g/day (2 g intravenously twice daily) for up to 14 days. The primary end point was the clinical response in the clinical modified intent-to-treat (c-mITT) and clinically evaluable (CE) populations at the test-of-cure visit 12 to 92 days after the last dose. The microbiologic response at the test-of-cure visit was also assessed. Safety was assessed by physical examination, laboratory results, and adverse event reporting. Five hundred twenty patients were included in the c-mITT population (tigecycline group, n = 261; combination group, n = 259), and 436 were clinically evaluable (tigecycline group, n = 223; combination group, n = 213). The clinical responses in the tigecycline and the combination vancomycin and aztreonam groups were similar in the c-mITT population (84.3% versus 86.9%; difference, -2.6% [95% confidence interval, -9.0, 3.8]; P = 0.4755) and the CE population (89.7% versus 94.4%; difference, -4.7% [95% confidence interval, -10.2, 0.8]; P = 0.1015). Microbiologic eradication (documented or presumed) occurred in 84.8% of the patients receiving tigecycline and 93.2% of the patients receiving vancomycin and aztreonam (difference, -8.5 [95% confidence interval, -16.0, -1.0]; P = 0.0243). The numbers of patients reporting adverse events were similar in the two groups, with increased nausea and vomiting rates in the tigecycline group and an increased incidence of rash and increases in alanine aminotransferase and aspartate aminotransferase levels in the combination vancomycin and aztreonam group. Tigecycline was shown to be safe and effective for the treatment of complicated skin and skin structure infections.

Efficacy and safety of tigecycline monotherapy compared with vancomycin plus aztreonam in patients with complicated skin and skin structure infections: Results from a phase 3, randomized, double-blind trial

OBJECTIVES

To compare the effect of tigecycline monotherapy, a first-in-class, expanded broad spectrum glycylcycline, with the combination of vancomycin and aztreonam (V + A) in the treatment of complicated skin and skin structure infections (cSSSI).

METHODS

A phase 3, double-blind study conducted in 8 countries enrolled adults with cSSSI who required intravenous (IV) antibiotic therapy for > or =5 days. Patients were randomly assigned (1:1) to receive either tigecycline or V + A for up to 14 days. Primary endpoint was the clinical cure rate at the test-of-cure visit. Secondary endpoints included microbiologic efficacy and in vitro susceptibility to tigecycline of bacteria that cause cSSSI. Safety was assessed by physical examination, laboratory analyses, and adverse event reporting.

RESULTS

A total of 596 patients were screened for enrollment, 573 were analyzed for safety, 537 were included in the clinical modified intent-to-treat (c-mITT) population, 397 were clinically evaluable (CE), and 228 were microbiologically evaluable (ME). At test-of-cure, cure rates were similar between tigecycline and V + A groups in the CE population (82.9% versus 82.3%, respectively) and in the c-mITT population (75.5% versus 76.9%, respectively). Microbiologic eradication rates (subject level) at test-of-cure in the ME population were also similar between tigecycline and V + A. Frequency of adverse events was similar between groups, although patients receiving tigecycline had higher incidence of nausea, vomiting, dyspepsia, and anorexia, while increased ALT/SGPT, pruritus, and rash occurred significantly more often in V + A-treated patients.

CONCLUSIONS

This study demonstrates that the efficacy of tigecycline monotherapy for the treatment of patients with cSSSI is statistically noninferior to the combination of V + A.

Controversies about the decubitus ulcer

Knowledge of the decubitus ulcer has made great progress in recent decades. No longer is the diagnosis of a bedsore, as it was in the iron lung days, almost a death warrant. One cannot cause to heal a patient who is in organ failure, nor can one necessarily prevent ulcers in a new spinal cord-injured patient. Reflecting on the common cold, one realizes that prevention is limited to covering the face when sneezing, and treatment is symptomatic. There is no way of eradicating the virus of the common cold, nor is there an appropriate treatment. The decubitus ulcer should be conceived of in a similar vein, until understanding is more complete and specific treatments are available.