Evaluation of the protective effect of the intranasal vaccines adjuvanted with bacterium-like particles against intestinal infection.

Mucosal vaccination presents a promising complement to parenteral vaccination. Bacterium-like particles (BLPs), peptidoglycan structures prepared from lactic acid bacteria, are explored as potential nasal vaccine adjuvants for respiratory infections. To date, studies on BLP-adjuvanted nasal vaccines against intestinal infections have remained limited. In this study, we demonstrated the efficacy of intranasal BLP-adjuvanted vaccination in controlling intestinal infections using the Citrobacter rodentium (C. rodentium) model in C57BL/6 mice. Intranasal vaccination of Intimin, an adhesin critical for intimate bacterial adhesion to colonic epithelial cells, combined with BLP (BLP+I) elicited robust Intimin-specific intestinal secretory IgA production, reduced bacterial load in feces and almost completely inhibited colonic hyperplasia, a characteristic symptom of C. rodentium infection in mice. Conversely, parenteral vaccination with Alhydrogel-adjuvanted Intimin failed to induce intestinal Intimin-specific IgA production, resulting in poor protection against C. rodentium infection. This underscores the pivotal role of mucosal IgA responses elicited by intranasal immunization in its protective efficacy. As this study did not delineate the precise protective mechanism conferred by BLP+I intranasal immunization against C. rodentium infection, further elucidation of the mechanisms underlying intranasal BLP+I immunization is required.

Emergence of multidrug-resistant Pandoraea sputorum in Japan.

Pandoraea is a pathogenic bacterium naturally resistant to various antimicrobials, including colistin. Here, we report the whole-genome sequence of Pandoraea sputorum, which exhibits high-level multidrug resistance, isolated from a hospitalized patient in Japan.

Emergence of Cutibacterium avidum with erm(X) on a Mobile Genetic Element Identical to That of Cutibacterium acnes.

We determined that the Cutibacterium avidum isolate TP-CV302, from a patient with acne vulgaris in Japan, had the macrolide-clindamycin resistance factor erm(X) located on Tn5432. Although this mobile genetic element (MGE) is well recognized in Cutibacterium acnes, it has not been found in Cutibacterium avidum.

Avidumicin, a novel cyclic bacteriocin, produced by Cutibacterium avidum shows anti-Cutibacterium acnes activity.

The prevalence of antimicrobial-resistant Cutibacterium acnes in acne patients has increased owing to inappropriate antimicrobial use. Commensal skin bacteria may play an important role in maintaining the balance of the skin microbiome by producing antimicrobial substances. Inhibition of Cu. acnes overgrowth can prevent the development and exacerbation of acne vulgaris. Here, we evaluated skin bacteria with anti-Cu. acnes activity. Growth inhibition activity against Cu. acnes was tested using 122 strains isolated from the skin of healthy volunteers and acne patients. Comparative genomic analysis of the bacterium with or without anti-Cu. acnes activity was conducted. The anti-Cu. acnes activity was confirmed by cloning an identified gene cluster and chemically synthesized peptides. Cu. avidum ATCC25577 and 89.7% of the Cu. avidum clinical isolates (26/29 strains) inhibited Cu. acnes growth. The growth inhibition activity was also found against other Cutibacterium, Lactiplantibacillus, and Corynebacterium species, but not against Staphylococcus species. The genome sequence of Cu. avidum showed a gene cluster encoding a novel bacteriocin named avidumicin. The precursor protein encoded by avdA undergoes post-translational modifications, supposedly becoming a circular bacteriocin. The anti-Cu. acnes activity of avidumicin was confirmed by Lactococcus lactis MG1363 carrying avdA. The C-terminal region of the avidumicin may be essential for anti-Cu. acnes activity. A commensal skin bacterium, Cu. avidum, producing avidumicin has anti-Cu. acnes activity. Therefore, avidumicin is a novel cyclic bacteriocin with a narrow antimicrobial spectrum. These findings suggest that Cu. avidum and avidumicin represent potential alternative agents in antimicrobial therapy for acne vulgaris.

Increased frequency of clindamycin-resistant Cutibacterium acnes strains isolated from Japanese patients with acne vulgaris caused by the prevalence of exogenous resistance genes.

Cutibacterium acnes, a resident bacterium of the skin, is a target for antimicrobial treatment of acne vulgaris, because it exacerbates inflammation. Recently, antimicrobial-resistant C. acnes strains have been isolated worldwide, and their prevalence has led to failure of antimicrobial treatment. This study aimed to analyze the antimicrobial resistance of C. acnes strains isolated from Japanese patients with acne vulgaris who visited the hospital and dermatological clinics between 2019 and 2020. Resistance rates to roxithromycin and clindamycin increased during 2019 to 2020 compared with those during 2013 to 2018. Additionally, the proportion of doxycycline-resistant and low-susceptibility strains (minimum inhibitory concentration [MIC] ≥8 µg/mL) increased. No difference in clindamycin resistance rates between patients with and without a history of antimicrobial use was observed during 2019 to 2020, which were significantly higher for patients with a history than for patients without a history during 2016 to 2018. The proportion of high-level clindamycin-resistant strains (MIC ≥256 µg/mL) gradually increased; particularly, the resistance rate was 2.5 times higher in 2020 than that in 2013. The proportion of strains showing high-level clindamycin resistance that also have the exogenous resistance genes erm(X) or erm(50), which confer high resistance, showed a strong positive correlation (r = 0.82). Strains with the multidrug resistance plasmid pTZC1 encoding erm(50) and tet(W) genes were frequent in clinic patients. Notably, most strains with erm(X) or erm(50) were classified as single-locus sequence types A and F (traditional types IA1 and IA2). Our data show that the prevalence of antimicrobial-resistant C. acnes is increasing in patients with acne vulgaris attributable to acquisition of exogenous genes in specific strains. To control the increasing prevalence of antimicrobial-resistant strains, it is important to select the appropriate antimicrobials while taking into consideration the latest information on resistant strains.

Multidrug Resistance Plasmid pTZC1 Could Be Pooled among Cutibacterium Strains on the Skin Surface.

Acne vulgaris is a chronic inflammatory skin disease that is exacerbated by Cutibacterium acnes. Although antimicrobials such as macrolides, clindamycin, and tetracyclines are used to treat acne caused by C. acnes, the increasing prevalence of antimicrobial-resistant C. acnes strains has become a global concern. In this study, we investigated the mechanism by which interspecies transfer of multidrug-resistant genes can lead to antimicrobial resistance. Specifically, the transfer of pTZC1 between C. acnes and C. granulosum isolated from specimens of patients with acne was investigated. Among the C. acnes and C. granulosum isolated from 10 patients with acne vulgaris, 60.0% and 70.0% of the isolates showed resistance to macrolides and clindamycin, respectively. The multidrug resistance plasmid pTZC1, which codes for macrolide-clindamycin resistance gene erm(50) and tetracycline resistance gene tet(W), was identified in both C. acnes and C. granulosum isolated from the same patient. In addition, whole-genome sequencing revealed that the pTZC1 sequences of C. acnes and C. granulosum showed 100% identity using comparative whole-genome sequencing analysis. Therefore, we hypothesize that the horizontal transfer of pTZC1 between C. acnes and C. granulosum strains may occur on the skin surface. The plasmid transfer test revealed a bidirectional transfer of pTZC1 between C. acnes and C. granulosum, and transconjugants that obtained pTZC1 exhibited multidrug resistance. In conclusion, our results revealed that the multidrug resistance plasmid pTZC1 could be transferred between C. acnes and C. granulosum. Furthermore, since pTZC1 transfer among different species may aid in the prevalence of multidrug resistant strains, antimicrobial resistance genes may have been pooled on the skin surface. IMPORTANCE The emergence of antimicrobial resistance not only in Cutibacterium acnes strain but also other skin bacteria such as Staphylococcus epidermidis is a big concern due to antimicrobial use for the treatment of acne vulgaris. Increased prevalence of macrolides-clindamycin resistant C. acnes relates to the acquisition of exogenous antimicrobial resistance genes. erm(50) is harbored by the multidrug resistance plasmid pTZC1, which has been found in C. acnes and C. granulosum strains isolated from patients with acne vulgaris. In this study, C. acnes and C. granulosum with pTZC1 were found in the same patient, and plasmid transfer between C. acnes and C. granulosum was proved by transconjugation assay. This study showed plasmid transfer between other species and the possibility of further prevalence antimicrobial resistance between Cutibacterium species.

Prevalence of antimicrobial-resistant Cutibacterium isolates and development of multiplex PCR method for Cutibacterium species identification.

INTRODUCTION: Cutibacterium species such as C. acnes, C. avidum, and C. granulosum are known anaerobic skin inhabitants and often cause surgical site infections. These species are genetically similar and are difficult to identify rapidly. In addition, their pathogenicity and antimicrobial resistance remain unknown. In this study, antimicrobial resistance in Cutibacterium isolates was studied and a multiplex PCR method for their identification was developed. METHODS: A total of 497 C. acnes, 71 C. avidum, and 25 C. granulosum strains which were isolated from the acne pustule and infectious regions, were used. RESULTS: The antimicrobial resistance rates of C. acnes, C. avidum, and C. granulosum strains isolated from patients with acne vulgaris were higher than those of strains isolated from patients with infectious diseases. In particular, macrolide-clindamycin-resistant strains were isolated most frequently from all species. Among the resistant strains, strains with 23S rRNA mutations were the most common in C. acnes (24.3%, 71/292), whereas C. avidum and C. granulosum strains were most frequently found with erm(X). For the first time, a C. granulosum strain carrying pTZC1, which codes erm(50) and tet(W), was isolated from patients with acne vulgaris. Regarding the rapid identification of causative pathogens from infectious regions, three Cutibacterium species were identified with 100% sensitivity and specificity using multiplex PCR method. CONCLUSIONS: Our data showed that antimicrobial resistance differed among Cutibacterium species. The multiplex PCR method may contribute to the rapid detection of Cutibacterium species and selection of appropriate antimicrobial agents.

Increased Prevalence of Minocycline-Resistant Staphylococcus epidermidis with tet(M) by Tetracycline Use for Acne Treatment.

Staphylococcus epidermidis, a major skin bacterium, can cause opportunistic infections. Use of antimicrobial agents against Cutibacterium acnes for acne treatment becomes a risk factor for emergence of antimicrobial-resistant skin bacteria. In this study, the impact of antimicrobial treatment of acne vulgaris on S. epidermidis antimicrobial resistance was assessed. A total of 344 S. epidermidis strains isolated from patients with acne vulgaris who visited hospital (165 strains) and dermatological clinics (179 strains), respectively, were analyzed. Except for doxycycline, the resistance rates were higher in strains isolated from patients who had used antimicrobials for acne treatment than in those isolated from patients who had not used antimicrobials. The prevalence rates of strains with erm(C) from patients who used macrolides and clindamycin (hospital, 78.0%; clinics, 61.3%) and those of strains with tet(M) from patients who used tetracyclines (hospital, 27.5%; clinics, 42.4%) were significantly higher than those of strains from patients who did not use antimicrobials (p < 0.05). All strains with erm(A) (8/8) and 91.7% strains with erm(C) (156/170) showed high-level resistance to macrolides and clindamycin (MIC ≥256 µg/mL). Furthermore, almost all strains with tet(M) showed resistance to minocycline. Our results showed that the use of antimicrobials for acne treatment may lead to an increased prevalence of antimicrobial-resistant S. epidermidis. In particular, the emergence of minocycline-resistant strains with tet(M) owing to the use of tetracyclines (doxycycline and minocycline) is a critical issue. Appropriate antimicrobial use for acne treatment may be an important strategy to prevent the emergence of antimicrobial-resistant skin bacteria.

Identification of a Transferable Linear Plasmid Carrying the Macrolide-Clindamycin Resistance Gene erm(X) in a Cutibacterium acnes Isolate from a Patient with Acne Vulgaris in Japan.

Cutibacterium acnes, one of the common skin bacteria, is known to exacerbate acne vulgaris. Macrolide-clindamycin-resistant C. acnes strains have been reported worldwide. In this study, we found a transferable linear plasmid carrying the macrolide-clindamycin resistance gene erm(X) in a C. acnes strain isolated from a patient with acne vulgaris.

Multidrug-resistant Cutibacterium avidum isolated from patients with acne vulgaris and other infections.

OBJECTIVES: Cutibacterium avidum, a human skin commensal bacterium, rarely causes infections. It has recently been shown that Cutibacterium acnes, another member of the genus, acts as an opportunistic pathogen in surgical site infections. However, the antimicrobial susceptibility and pathogenicity of C. avidum remain unknown. METHODS: We investigated the epidemiological features and antimicrobial susceptibility of C. avidum isolated from patients with acne vulgaris and other infections. RESULTS: Cutibacterium avidum strains were isolated from patients with acne vulgaris (29 strains) and other infections (12 strains). Clarithromycin and clindamycin resistance was observed in 65.9% (27/41) of strains. In addition, ciprofloxacin resistance was observed in 34.1% (14/41) of strains, of which 13 also exhibited resistance to macrolides and clindamycin. Notably, the macrolide-clindamycin resistance gene erm(X) was found on the chromosome of 92.6% (25/27) of clindamycin-resistant strains and may be prevalent owing to transmission among C. avidum strains. Ciprofloxacin-resistant strains developed amino acid substitutions in GyrA owing to the use of antimicrobial agents. Pulsed-field gel electrophoresis (PFGE) analysis revealed that only a few strains exhibited 100% similarity. Additionally, no clustering associated with antimicrobial resistance, biofilm-forming ability or type of infection was observed. CONCLUSION: Our study revealed that erm(X) may be frequently disseminated in C. avidum, and multidrug-resistant C. avidum strains may colonise the skin of patients with acne vulgaris and other infections. Therefore, the prevalence of multidrug-resistant C. avidum and the use of antimicrobial agents for the treatment of acne vulgaris and other infections associated with C. avidum should be monitored.

Cutibacterium acnes phylogenetic type IC and II isolated from patients with non-acne diseases exhibit high-level biofilm formation.

Cutibacterium (formerly Propionibacterium) acnes is an important for not only exacerbating factor of acne vulgaris but also pathogen of surgical site infections (SSIs) in orthopedics and plastic surgery. Although biofilm-forming (BF) C. acnes are associated with intractable SSI, characteristics of these strains were still unknown. Here, we explored detailed molecular epidemiological features of BF C. acnes isolated as causative pathogen of infectious diseases. Phylogenetic types of 205 C. acnes strains isolated between 2013 and 2018 from 18 clinical departments of a university hospital in Japan were determined by single-locus sequence type (SLST). Clade H (traditional type IC) and K (type II) which are less relevant with healthy skin and acne vulgaris, were detected in 26.8% (55/205) and 16.1% (33/205) of the strains, respectively. The incidence of them was significantly higher than that of acne patients (H and K, each 2.9%, P < 0.05). In addition, SLST distribution of C. acnes strains differed by each department and isolation site. When biofilm formation was quantified, 51 strains (24.9%) were defined as high-BF strains. Notably, most high-BF strains were classified into the strains of clade H (56.4%, 31/55) and clade K (54.4%, 18/33), and these strains were frequently found in the strains isolated from patients of medical emergency center and plastic surgery. Similarly, high-BF strains were frequently found among the isolates from blood (35.7%) and catheters (30.0%), with a high proportion belonging to clades H and K. Compared to C. acnes strains isolated from acne patients, antimicrobial-resistant strains were less identified in non-acne patients. Our findings showed that pathogenicity of C. acnes strains differs by their phylogenetic types. Furthermore, we showed clade H and K have the ability of high biofilm formation and suggest that these strains have potential to become a risk factor for SSI.

Antimicrobial activity and additive effect of the modified Gingyo-san with antimicrobials against Helicobacter pylori.

INTRODUCTION: Helicobacter pylori is an important factor in the development of gastroduodenal ulcers and gastric cancer. Although H. pylori eradication therapy has been employed, the eradication rate has decreased in recent years owing to an increase in clarithromycin-resistant strains. We previously reported the anti-infective effect of herbal medicines against several bacterial species. Here, we evaluated the growth inhibitory activity of herbal medicines alone and in combination with antimicrobials against H. pylori. METHODS AND RESULTS: Nine of 37 herbal medicines inhibited the growth of H. pylori ATCC700392. In particular, modified Gingyo-san showed the strongest growth inhibitory activity with a minimum inhibitory concentration (MIC) of 512 µg/ml for not only ATCC700392 but also clarithromycin-resistant strains having a 23 S rRNA mutation. Results of Time-Kill Kinetics Assay showed that 1 mg/mL modified Gingyo-san treatment for one hour killed 50% of the H. pylori population. Furthermore, modified Gingyo-san showed additive effects with clarithromycin, amoxicillin, and metronidazole against H. pylori ATCC700392 and clarithromycin-resistant strains. CONCLUSIONS: Our findings showed that modified Gingyo-san inhibits the growth of H. pylori and improves antimicrobial susceptibility when used in combination. Therefore, modified Gingyo-san has the potential to enhance the eradication rate of clarithromycin-resistant H. pylori.