Inactivation of Gram-negative and Gram-positive bacteria in red cell concentrates using INACTINE PEN110 chemistry

BACKGROUND AND OBJECTIVES

The risk of transfusion-transmitted bacterial infections as a result of the presence of bacteria in blood is one of the major concerns in transfusion medicine. The purpose of this study was to investigate whether bacteria inoculated into red blood cell concentrates can be inactivated by the INACTINE PEN110 pathogen-reduction process. Four bacterial species were chosen for the study: anaerobic Gram-positive Clostridium perfringens and Propionibacterium acnes, known to be transfusion-transmitted; and two Gram-negative species, Acinetobacter johnsonii and Acinetobacter lwoffii, recently reported to be a common cause of transfusion-associated infections in Europe.

MATERIALS AND METHODS

Identical units of leucoreduced red cell concentrates were inoculated with A. johnsonii, A. lwoffii, C. perfringens, or P. acnes. The 4 degrees C control units were put on storage immediately after receiving the spike. The test units were subjected to PEN110 treatment and then stored. The bacterial titre in all units was monitored during a 6-week storage period.

RESULTS

The PEN110 inactivation of all tested bacterial strains was time- and titre-dependent. For A. johnsonii and A. lwoffii, no viable bacteria were detected in the units spiked with up to 10(4) colony-forming units (CFU)/ml and treated with PEN110. For red cell units spiked with 10(4)-10(5) CFU/ml of C. perfringens and P. acnes, no viable bacteria were detected in the units treated with PEN110. In control units, there was a gradual decrease in A. johnsonii, A. lwoffii and C. perfringens titres during cold storage, while P. acnes titres remained stable.

CONCLUSIONS

The PEN110 pathogen-reduction process was demonstrated to inactivate high titres of A. johnsonii, A. lwoffii, C. perfringens and P. acnes in red cell concentrates.

[Study on anti-bacterium activity of ginkgolic acids and their momomers]

OBJECTIVE

Ginkgolic acids and their three monomers were separated from ginkgo sarcotestas. The anti-bacterium activity of ginkgolic acids were tested. The relation between the anti-bacterium activity and side chain of ginkgolic acid were studied.

METHOD

The MIC of ginkgolic acids and their three monomers and salicylic acid were tested.

RESULTS

Ginkgolic acid has strong inhibitive effect on G+-bacterium. Salicylic acid has no side chain, so no anti-bacterial activity. When the length of gingkolic acid side chain is C13:0, it has the strongest anti-bacterial activity in three monomers.

CONCLUSION

The side chain of ginkgolic acid is the key functional group that possessed anti-bacterial activity. The length of Ginkgolic acid was the main effective factor of anti-bacterial activity.

Topical aminolaevulinic acid-photodynamic therapy for the treatment of acne vulgaris: a study of clinical efficacy and mechanism of action

BACKGROUND

Acne affects 83-95% of 16-year-olds of both sexes, and many seek help from a clinician. Emerging problems with conventional acne treatments, specifically antibiotic resistance of Propionibacterium acnes and fears over the safety and tolerance of oral isotretinoin, create a demand for novel treatment modalities in acne.

OBJECTIVES

To study the efficacy of aminolaevulinic acid-photodynamic therapy (ALA-PDT) in the treatment of acne and to identify the mode of action, looking specifically at the effects on surface numbers of P. acnes and on sebum excretion.

METHODS

Ten patients (nine men and one woman, age range 16-40 years) with mild to moderate acne on their backs were recruited. Each patient's back was marked with four 30-cm2 areas of equal acne severity. Each site was then randomly allocated to either ALA-PDT treatment, light alone, ALA alone or an untreated control site. At baseline, numbers of inflammatory and noninflammatory acne lesions were counted, sebum excretion measured by Sebutapes (CuDerm, Dallas, TX, U.S.A.) and surface P. acnes swabs performed. ALA cream (20% in Unguentum Merck) was applied under occlusion to the ALA-PDT and ALA alone sites for 3 h. Red light from a diode laser was then delivered to the ALA-PDT and light alone sites (635 nm, 25 mW cm(-2), 15 J cm(-2)). Each patient was treated weekly for 3 weeks. At each visit acne lesion counts were performed and 3 weeks following the last treatment sebum excretion rates and P. acnes swabs were repeated.

RESULTS

There was a statistically significant reduction in inflammatory acne lesion counts from baseline after the second treatment at the ALA-PDT site but not at any of the other sites. No statistically significant reduction in P. acnes numbers or sebum excretion was demonstrated at any sites including the ALA-PDT site.

CONCLUSIONS

ALA-PDT is capable of clinically improving acne. An alternative mode of action for ALA-PDT other than direct damage to sebaceous glands or photodynamic killing of P. acnes is suggested from the results of this study.

Antibiotic resistance in the topical treatment of acne vulgaris

Topical antimicrobial agents are the first line of treatment in mild to moderate acne vulgaris. The primary pathogenic agent implicated in the development of inflammatory acne is Propionibacterium acnes. P acnes also may play a secondary role in noninflammatory acne or comedogenesis. Over the past 20 years, concern has grown about the gradual worldwide increase in the prevalence of antibiotic-resistant P acnes strains. Factors associated with the development of resistant P acnes following treatment with topical antibiotics, clinical relevance of antibiotic resistance, and strategies to reduce the incidence of P acnes resistance are discussed in this review.

Antibacterial activity of ent -kaurene diterpenoids from Rabdosia rosthornii

Biological activities of ent-kaurene diterpenoids, rosthornins A-D, isolated from the ether extract of the dried leaves of Rabdosia rosthornii (Diels) Hara (Labiatae) were tested. They exhibited antibacterial activity specifically against Gram-positive bacteria, among which Propionibacterium acnes was noted to be the most susceptible.

Topical retinoid and antibiotic combination therapy for acne management

The agents most commonly used in combination for the management of acne include topical retinoids and antibiotics. Topical retinoids normalize desquamation of the follicular epithelium, whereas antibiotics inhibit the growth of P. acnes and the production of free fatty acids. This therapeutic combination decreases comedogenesis, bacterial growth, and inflammation, thus targeting three of the four pathogenic factors associated with acne. Efficacy and tolerance are maximized with combination therapy, and the degree of skin irritation is minimized. Furthermore, adjunctive therapy with topical retinoids and antibiotics tends to produce results more quickly than single-agent therapy. This article will examine the individual agents used in combination for acne management, and discuss the mechanisms by which they achieve efficacy. The rationale of utilizing topical retinoids with antibiotics will be highlighted, particularly in relation to improved tolerance and reduced irritation.

Propionibacterium acnesbiotypes and susceptibility to minocycline andKeigai-rengyo-to

BACKGROUND

Propionibacterium acnes is the predominant organism in acne lesions, but the sensitivity of different biotypes of P. acnes to therapeutic agents has seldom been reported.

METHODS

To characterize biotypes of P. acnes and to measure the effects of Keigai-rengyo-to (KRT) and minocycline (MINO) on clinical P. acnes isolates.

RESULTS

Propionibacterium acnes biotype III (BIII) is the most common form of identified acne lesion, followed by P. acnes biotype I. BIII was isolated from mild, moderate and severe severity and the average lipase activity of BIII was higher than that of Biotypes I, II, IV and V. No significant differences in the decrease of free fatty acid production elicited by KRT or by MINO were found between BIII and the other biotypes. The degree of decreased butyric acid production was greater than that of propionic acid production in the medium supplemented with MINO. The percent decrease of butyric acid production elicited by 1 mg/mL of KRT was the same as that elicited by 0.1 microg/mL of MINO. Among biotypes of P. acnes, the minimal inhibitory concentrations of agents tested were generally higher in erythritol-positive biotypes than in erythritol-negative biotypes.

CONCLUSION

The high frequency of BIII might be responsible for the severity of acne in patients. It seems that if the same concentrations of MINO and KRT are used, the antilipase activity of MINO is stronger than that of KRT. Minocycline also has a direct anti-lipase activity against P. acnes. The mechanism underlying the influence of erythritol on the susceptibility of P. acnes to these agents remains unknown.

Propionibacterium acnes and the Pathogenesis of Progressive Macular Hypomelanosis

BACKGROUND

Progressive macular hypomelanosis is a common hypopigmentation mainly on the central parts of the trunk, predominantly in young adults, especially women. It is often mistaken for pityriasis versicolor and pityriasis alba. It occurs in all races and has been described in many parts of the world. We discovered follicular red fluorescence restricted to lesional skin. We suspected a relation with a porphyrin-producing bacteria residing in sebum of the pilosebaceous duct, and we therefore performed a study in 8 patients. Observation In all biopsy specimens taken from lesional skin of 8 women, we could demonstrate gram-positive bacteria in the pilosebaceous duct, and a mild perifollicular lymphocytic infiltrate was seen. In all but 1 patient, Propionibacterium acnes was yielded from cultured biopsy specimens taken from follicular lesional skin. Healthy follicular skin did not show bacteria in histological sections, and cultures did not yield anaerobic bacteria.

CONCLUSIONS

There seems to be a relation between the presence of P acnes and the hypopigmented macules. We propose that a factor is produced by these strains of P acnes, which interfere with melanogenesis. Based on these observations, we are undertaking a clinical trial to find a treatment for this troubling, intractable disease.

Current concepts of the pathogenesis of acne: implications for drug treatment

The pathogenesis of acne is complex, with strong evidence supporting the involvement of sebaceous hyperplasia, follicular hyperkeratinisation, bacterial hypercolonisation, as well as immune reactions and inflammation. High sebum concentrations and follicular hyperkeratinisation lead to a change of the follicular milieu with consecutive proliferation of bacteria, chiefly Propionibacterium acnes. This leads to further increased production of the pro-inflammatory cytokines interleukin-1alpha and tumour necrosis factor alpha by T cells and keratinocytes, leading to proliferation of both cell types. Follicular keratinocytes fail to differentiate by apoptosis and produce hypergranulosis similar to the impermeable skin outer layer, resulting in the formation of microcomedones. Further inflammatory responses lead to the development of increasing degrees of severity in inflammatory forms of acne. Retinoids aid the differentiation and reduce the hyperproliferation of keratinocytes, and can inhibit the migration of leucocytes. Combination therapy using retinoids plus benzoyl peroxide or antibacterials can treat existing acne lesions faster than the individual agents alone and can also prevent the development of new lesions. The new retinoids (e.g. adapalene) have not only the typical potent comedolytic activity but also anti-inflammatory effects. When added to antibacterial therapy, topical retinoids demonstrate faster and significantly greater reduction of inflammatory acne lesions and comedones than antibacterials alone.

Propionibacterium acnes resistance: a worldwide problem

Antibiotic therapy directed against Propionibacterium acnes has been a mainstay of treatment for more than 40 years. Despite years of widespread use of systemic tetracyclines and erythromycin, change in P. acnes sensitivity to antibiotics was not seen until the early 1980s. The first clinically relevant changes in P. acnes antibiotic sensitivity were found in the USA shortly after the introduction of topical formulations of erythromycin and clindamycin. By the late 1980s, P. acnes strains with very high MIC levels for erythromycin and elevated MICs for tetracycline were increasingly found in the UK and the USA. Mutations in the genes encoding the 23S and 16S subunits of ribosomal RNA were first identified in the UK and also seen in a recent survey from clinics in Europe, Japan, Australia and the USA. In addition, strains were found in which these known mutations could not be identified, indicating that as yet unidentified resistance mechanisms have evolved. These findings indicate the need to develop strategies to minimize the use of antibiotics in acne therapy.

Antibiotic resistance of Propionibacterium acnes in acne vulgaris

Acne vulgaris is a common skin disease affecting all ages. Antibiotics remain the most common prescribed agent for the treatment of acne. Improper use of antibiotics in the dermatological setting needs to be evaluated to prevent the increasing prevalence of antibiotic resistance.

Inhibition of lipase activity in antibiotic-resistant propionibacterium acnes strains

BACKGROUND AND OBJECTIVE

Erythromycin-sensitive and/or clindamycin-sensitive strains of Propionibacterium acnes show a reduced lipase production at levels below the minimal growth-inhibitory concentration (MIC). The objective of this study was to determine whether erythromycin and clindamycin concentrations far below the MIC inhibit lipase production in P. acnes strains resistant to these antibiotics.

METHODS

Of 42 P. acnes strains, 10 showed an MIC >256 micro g/ml for erythromycin. Two strains showed MICs of 0.19 and 0.25 micro g/ml, while the MIC of the remaining strains was <or=0.016 micro g/ml. Lipase activity was determined up to a concentration of 192 micro g/ml by cultivation on spirit blue agar + lipase reagent. The 10 strains whose erythromycin MIC was >256 micro g/ml were also tested for lipase inhibition by clindamycin. While this method fails to differentiate between inhibition of lipase production and inhibition of lipase activity, the absence of inhibition of lipase activity rules out inhibition of lipase production.

RESULTS

Inhibition of lipolysis by sub-MIC concentrations was demonstrated only for clindamycin in 3 P. acnes strains. However, lipase inhibition was seen only at the dilution level immediately below the MIC.

CONCLUSIONS

Resistant P. acnes strains with high erythromycin and/or clindamycin MICs can be ruled out to show in vitro inhibition of lipase production at antibiotic concentrations far below the MIC.

Proton magic angle spinning NMR reveals new features in photodynamically treated bacteria

The bacterium Propionibacterium acnes is light-sensitive due to porphyrin-induced photosensitization. The light sensitivity increases with incubation of 5-aminolevulinic acid, ALA. For the first time, 1H magic angle spinning NMR spectroscopy is used to describe the photoinduced changes in the bacterium after ALA incubation. Successful photosensitization was performed with light-emitting diodes in the blue and red regions (430 and 654 nm, respectively). The irradiation setup, suitable for irradiation of bacterium suspensions in petri dishes is described. For NMR studies blue light diodes with about 90 micromol/m2s were chosen. After blue light irradiation, the endogenous glycine betaine, proline, glutamate and choline levels in P. acnes decreased with increasing irradiation time. For sublethal light doses (50% survival fraction), the endogenous glycine betaine level decreased 80% on average. The corresponding percentages for proline, choline and glutamate were about 40, 25 and 10, respectively. It is hypothesized that the irradiation, inducing porphyrin photosensitization amplified by ALA incubation, leads to elimination of the osmolyte glycine betaine and possibly also proline by so-called regulatory volume decrease (RVD) mechanisms. These mechanisms are known to be active in several prokaryotic and eukaryotic cells when exposed to hypotonic stress. They are also known to be present in several eukaryotic cells during photodynamic therapy (PDT) exposure leading to hypotonoc stress. The findings contribute to the knowledge of the inactivation mechanisms of P. acnes in photosensitization, and could therefore be of interest in the efforts to use PDT as treatment of the acne disease.

Eradication of Propionibacterium acnes by its endogenic porphyrins after illumination with high intensity blue light

Propionibacterium acnes is a Gram-positive, microaerophilic bacterium that causes skin wounds. It is known to naturally produce high amounts of intracellular porphyrins. The results of the present study confirm that the investigated strain of P. acnes is capable of producing endogenic porphyrins with no need for any trigger molecules. Extracts from growing cultures have demonstrated emission peaks around 612 nm when excited at 405 nm, which are characteristic for porphyrins. Endogenic porphyrins were determined and quantified after their extraction from the bacterial cells by fluorescence intensity and by elution retention time on high-performance liquid chromatography (HPLC). The porphyrins produced by P. acnes are mostly coproporphyrin, as shown by the HPLC elution patterns. Addition of delta-aminolevulinic acid (ALA) enhanced intracellular porphyrin synthesis and higher amounts of coproporphyrin have been found. Eradication of P. acnes by its endogenic porphyrins was examined after illumination with intense blue light at 407-420 nm. The viability of 24 h cultures grown anaerobically in liquid medium was reduced by less than two orders of magnitude when illuminated once with a light dose of 75 J cm(-2). Better photodynamic effects were obtained when cultures were illuminated twice or three times consecutively with a light dose of 75 J cm(-2) and an interval of 24 h between illuminations. The viability of the culture under these conditions decreased by four orders of magnitude after two illuminations and by five orders of magnitude after three illuminations. When ALA-triggered cultures were illuminated with intense blue light at a light dose of 75 J cm(-2) the viability of the treated cultures decreased by seven orders of magnitude. This decrease in viability can occur even after a single exposure of illumination for the indicated light intensity. X-ray microanalysis and transmission electron microscopy revealed structural damages to membranes in the illuminated P. acnes. Illumination of the endogenous coproporphyrin with blue light (407-420 nm) apparently plays a major role in P. acnes photoinactivation. A treatment protocol with a series of several illuminations or illumination after application of ALA may be suitable for curing acne. Treatment by both pathways may overcome the resistance of P. acnes to antibiotic treatment.

Is antibiotic resistance in cutaneous propionibacteria clinically relevant? : implications of resistance for acne patients and prescribers

It is well recognized that some patients with acne do not respond adequately to antibiotic therapy. It is important to distinguish antibiotic recalcitrant acne which we would suggest represents acne that shows a diminished response to treatment irrespective of the cause as opposed to 'antibiotic-resistant acne' which is acne that is less responsive to treatment as a direct consequence of skin colonization with resistant propionibacteria. Here we show that antibiotic-resistant acne is not just a theoretical possibility but a real phenomenon that could have important consequences for patients and prescribers. The relationship between skin colonization by antibiotic-resistant propionibacteria and treatment outcomes is a complex one that is explained at the follicular level by physiological differences affecting local drug concentrations. A systematic review of the literature on antibiotic-resistant propionibacteria revealed methodological shortcomings in studies of their prevalence and a paucity of evidence on their clinical significance. Despite the elucidation of resistance mechanisms in cutaneous propionibacteria, our continuing inability to distinguish between strains of Propionibacterium acnes means that we still do not fully understand how resistance spreads, although person-to-person transfer is most likely. Finally, we present a decision tree for acne management in an era of prudent antimicrobial prescribing that provides an alternative to existing treatment algorithms by placing topical retinoids and not antibiotics at the cornerstone of acne management.

Comparison of chloroxylenol 0.5% plus salicylic acid 2% cream and benzoyl peroxide 5% gel in the treatment of acne vulgaris: a randomized double-blind study

A 12-week double-blind randomized study was performed to compare benzoyl peroxide 5% (BP) gel and chloroxylenol 0.5% plus salicylic acid 2% (PCMX + SA) cream (Nisal cream) for efficacy and adverse reactions. Thirty-seven volunteers participated in the study, 19 in the BP group and 18 in the PCMX + SA group. The patients applied the medication twice daily to the entire face. Clinical evaluation and lesion counts were obtained at 0, 3, 6, 9 and 12 weeks. At week 12 both groups showed a marked improvement in both inflammatory and noninflammatory lesions (60% and 54% for the BP group and 62% and 56% for and 56% for the PCMX + SA group, respectively). Although PCMX + SA showed a slightly stronger keratolytic effect throughout the study period, there was no statistically significant difference in the reduction of the papulopustules or comedones between the two groups. Adverse effects such as erythema and photosensitivity were significantly fewer in the PCMX + SA group at week 12 (p = 0.0002 and p = 0.05, respectively). These results suggest that PCMX + SA cream is as effective as BP gel in the treatment of papulopustular and comedonal acne and that it is better tolerated.

Effect of lipase activities of Propionibacterium granulosum and Propionibacterium acnes

We studied the lipase activities of Propionibacterium granulosum, P. acnes and the suppression of these activities by Jumi-haidoku-to (JHT). Lipase activity of P. acnes biotype III (BIII) was strongest, while that of P. granulosum was faintly expressed. Compared with the control medium, the production of propionic and butyric acids was suppressed by all the tested mediums combined with JHT. The decrease in these acids produced by JHT was significantly higher in P. granulosum than in P. acnes. Although P. acnes BIII may produce a strong effect on acne, the presence of P. granulosum should not be ignored. Further research is required on the correlation between P. acnes and P. granulosum.

Anti-inflammatory effects of erythromycin and tetracycline on Propionibacterium acnes induced production of chemotactic factors and reactive oxygen species by human neutrophils

Propionibacterium acnes (P. acnes), an anaerobic pathogen, plays an important role in the pathogenesis of acne and seems to initiate the inflammatory process by producing neutrophil chemotactic factors (NCF). Once neutrophils attracted by bacterial chemoattractants reach the inflamed site, they release inflammatory mediators such as lysosomal enzymes and reactive oxygen species (ROS). Previously, it has been shown that antibiotics may affect acne by means other than their anti-bacterial effects. Thus, we investigated the effect of subminimal inhibitory concentration (sub-MIC) of tetracycline and erythromycin on production of NCF and ROS. NCF was tested in vivo in a mouse model and ROS was estimated on human PMNL in vitro, by nitroblue tetrazolium dye reduction test (NBT) and cytochrome-C reduction test. Tetracycline (CS-T) and Erythromycin (CS-E) treated cultures showed a significant reduction of 35.8% and 58.3% in NCF production respectively, as compared to P. acnes stimulated cultures. Tetracycline and erythromycin at their sub-MIC also significantly inhibited release of ROS from human PMNL. Thus, tetracycline and erythromycin, besides having antibacterial activity, also have an anti-inflammatory action. These antibiotics reduce the capacity of P. acnes to produce NCF, as well decrease its ability to induce ROS from PMNL.

Effects of Roxithromycin on the production of lipase and neutrophil chemotactic factor by Propionibacterium acnes

BACKGROUND

The macrolide antibiotic roxithromycin is effective against acne associated with inflammation, but the mechanism by which this is achieved has not been clarified.

OBJECTIVE

We studied the effects of roxithromycin on the production of lipase and neutrophil chemotactic factor by Propionibacterium acnes in vitro.

RESULTS

Roxithromycin significantly inhibited the production of lipase and neutrophil chemotactic factor by P. acnes at a concentration one eighth of the MIC, at which the growth curve of P. acnes is not affected.

CONCLUSION

One mechanism of the effectiveness of roxithromycin in acne therapy is thought to be the inhibition of bacterial lipase and neutrophil chemotactic factor production by P. acnes.

Comparative efficacy of clindamycin and benzoyl peroxide for in vivo suppression of Propionibacterium acnes

BACKGROUND

Benzoyl peroxide and clindamycin are the two most widely prescribed topical antimicrobials in the treatment of acne.

AIM

To compare the antimicrobial efficacy, in vivo, of benzoyl peroxide and clindamycin against Propionibacterium acnes.

METHODS

Two groups of 10 subjects each, with comparable mean P. acnes baseline counts of log 5.75 to 5.85, underwent twice daily application of benzoyl peroxide or clindamycin for 14 days.

RESULTS

The results of quantitatively sampling P. acnes after 3, 7 and 14 days of treatment showed that Triaz 6% benzoyl peroxide special gel produced faster and significantly greater reductions in P. acnes than did the 1% clindamycin phosphate in Cleocin-T lotion (p < 0.01). These results were paralleled by the greater reductions produced by Triaz versus Cleocin (p < 0.05) in P. acnes fluorescence.

CONCLUSION

Benzoyl peroxide formulations suppress the follicular population of P. acnes more rapidly and to a greater degree than topical antibiotics such as clindamycin.