Clinical metagenomic analysis of bacterial communities in breast abscesses of granulomatous mastitis

Evaluation of significantly changed chemokine factors of idiopathic granulomatous mastitis in non-puerperal patients

Idiopathic granulomatous mastitis (IGM), a recurrent inflammation disease of the non-lactating breast, has had an increasing clinical morbidity rate in recent years, and its complicated symptoms and unclear etiology make it challenging to treat. This rare benign inflammatory breast disease, centered on the lobules, represents the most challenging type of non-puerperal mastitis (NPM), also known as non-lactating mastitis. In this study, patients diagnosed with IGM (M, n = 23) were recruited as cases, and patients with benign control breast disease (C, n = 17) were enrolled as controls. Cytokine microarray detection measured and analyzed the differentially expressed cytokine factors between IGM and control patients. Then, we verified the mRNA and protein expression levels of the significantly changed cytokine factors using Q-RT-PCR, ELISA, western blot, and IHC experiments. The cytokine factor expression levels significantly changed compared to the control group. We observed a significant increase between IGM and control patients in cytokine factors expression, such as interleukin-1β (IL-1β), monokine induced by gamma interferon (MIG), macrophage inflammatory protein (MIP)-1α, MIP-1β, tumor necrosis factor receptor 2 (TNF RII). Then, we verified the expression of these top five dysregulated factors in both mRNA and protein levels. Our results demonstrated the cytokine map in IGM and indicated that several cytokines, especially chemokines, were associated with and significantly dysregulated in IGM tissues compared to the control group. The chemokine factors involved might be essential in developing and treating IGM. These findings would be helpful for a better understanding of IGM and offer valuable insights for devising novel diagnostic and therapeutic strategies.

Pathological manifestations of granulomatous lobular mastitis

Granulomatous lobular mastitis (GLM) is a rare inflammatory breast disease with unknown etiology, characterized by non-caseous granulomatous inflammation of the lobules, which infiltrate lymphocytes, neutrophils, plasma cells, monocytes, and eosinophils may accompany. GLM is often misdiagnosed as breast cancer due to the lack of specificity in clinical and imaging examinations, and therefore histopathology is the main basis for confirming the diagnosis. This review provides an overview of the pathological features of granulomatous lobular mastitis and cystic neutrophil granulomatous mastitis (CNGM, a pathologic subtype of GLM). As well as pathologic manifestations of other breast diseases that need to be differentiated from granulomatous lobular mastitis such as breast tuberculosis, lymphocytic mastopathy/diabetic mastopathy, IgG4-related sclerosing mastitis (IgG4-RSM), nodular disease, Wegener's granulomatosis, and plasma cell mastitis. Besides, discusses GLM and CNGM, GLM and breast cancer, emphasizing that their relationship deserves further in-depth exploration. The pathogenesis of GLM has not yet been clearly articulated and needs to be further explored, pathology enables direct observation of the microscopic manifestations of the disease and contributes to further investigation of the pathogenesis.

Clinical characteristics and therapeutic strategy of granulomatous mastitis accompanied by Corynebacterium kroppenstedtii: a retrospective cohort study

BACKGROUND

Increasing evidence has suggested that Corynebacterium kroppenstedtii is associated with some cases of granulomatous mastitis, mostly based on pathology or microbiology. We aimed to identify the clinical characteristics and treatment regimens for granulomatous mastitis with Corynebacterium kroppenstedtii infection. Understanding these clinical features is essential for patient care.

METHODS

We retrospectively collected data on 201 patients who were pathologically diagnosed with granulomatous mastitis and had microbiological results of either Corynebacterium kroppenstedtii or no bacterial growth and recorded and analysed their demographics, clinical characteristics, and clinical outcomes.

RESULTS

There were 107 patients in the CK group and 94 patients in the negative group. Sinus formation (x² = 13.028, p = 0.000), time to complete remission at the first treatment period (Z = -3.027, p = 0.002), diameter of breast mass at first-time medical consultancy (Z = -2.539, p = 0.011) and recurrence (x² = 4.953, p = 0.026) were statistically significant. Age (Z = -1.046, p = 0.295), laterality (x² = 4.217, p = 0.121), time to presentation since the last delivery (x² = 0.028, p = 0.868), BMI (Z = -0.947, p = 0.344), lactation time (Z = -1.378, p = 0.168), parity (x² = 1.799, p = 0.180), gravida (Z = -0.144, p = 0.885), history of lactational mastitis or abscess (x² = 0.115, p = 0.734), local trauma (x² = 0.982, p = 0.322), hyperprolactinemia (x² = 0.706, p = 0.401), erythema nodosum (x² = 0.292, p = 0.589), and nipple discharge (x² = 0.281, p = 0.596) did not demonstrate statistical significance. Regarding recurrence related to therapeutic strategy, except for surgery combined with immunosuppressants (x² = 9.110, p = 0.003), which was statistically significant, none of the other treatment regimens reached statistical significance. The recurrence rate of patients in the CK group using rifampicin in their treatment course was 22.0% (x² = 4.892, p = 0.027).

CONCLUSIONS

Granulomatous mastitis accompanied by Corynebacterium kroppenstedtii more easily forms sinuses and has a higher recurrence rate. Both of the clinical characteristics may indicate that Corynebacterium kroppenstedtii plays an important role in the development and progression of granulomatous mastitis. Lipophilic antibiotics may be essential for granulomatous mastitis with Corynebacterium kroppenstedtii infection.

Antibiotic resistance and resistance mechanism of Corynebacterium kroppenstedtii isolated from patients with mastadenitis

To investigate the antibiotic resistance and resistance mechanism of Corynebacterium kroppenstedtii (C. kroppenstedtii) isolated from patients with mastadenitis. Ninety C. kroppenstedtii clinical isolates were obtained from clinical specimens in 2018-2019. Species identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antimicrobial susceptibility testing was performed by the broth microdilution method. The resistance genes were detected using PCR and DNA sequencing. The results of antimicrobial susceptibility testing indicated that the resistance rates of C. kroppenstedtii to erythromycin and clindamycin, ciprofloxacin, tetracycline, and trimethoprim-sulfamethoxazole were 88.9%, 88.9%, 67.8%, 62.2%, and 46.6%, respectively. None of the C. kroppenstedtii isolates was resistant to rifampicin, linezolid, vancomycin, or gentamicin. The gene of erm(X) was detected in all clindamycin and erythromycin-resistant strains. The gene of sul(1) and tet(W) were detected among all trimethoprim sulfamethoxazole-resistant strains and tetracycline-resistant strains, respectively. Furthermore, 1 or 2 amino acid mutations (mainly single mutation) were observed in the gyrA gene among ciprofloxacin-resistant strains.

Profiling Microbial Communities in Idiopathic Granulomatous Mastitis

Idiopathic granulomatous mastitis (IGM) is a rare and benign inflammatory breast disease with ambiguous aetiology. Contrastingly, lactational mastitis (LM) is commonly diagnosed in breastfeeding women. To investigate IGM aetiology, we profiled the microbial flora of pus and skin in patients with IGM and LM. A total of 26 patients with IGM and 6 patients with LM were included in the study. The 16S rRNA sequencing libraries were constructed from 16S rRNA gene amplified from total DNA extracted from pus and skin swabs in patients with IGM and LM controls. Constructed libraries were multiplexed and paired-end sequenced on HiSeq4000. Metagenomic analysis was conducted using modified microbiome abundance analysis suite customised R-resource for paired pus and skin samples. Microbiome multivariable association analyses were performed using linear models. A total of 21 IGM and 3 LM paired pus and skin samples underwent metagenomic analysis. Bray−Curtis ecological dissimilarity distance showed dissimilarity across four sample types (IGM pus, IGM skin, LM pus, and LM skin; PERMANOVA, p < 0.001). No characteristic dominant genus was observed across the IGM samples. The IGM pus samples were more diverse than corresponding IGM skin samples (Shannon and Simpson index; Wilcoxon paired signed-rank tests, p = 0.022 and p = 0.07). Corynebacterium kroppenstedtii, reportedly associated with IGM in the literature, was higher in IGM pus samples than paired skin samples (Wilcoxon, p = 0.022). Three other species and nineteen genera were statistically significant in paired IGM pus−skin comparison after antibiotic treatment adjustment and multiple comparisons correction. Microbial profiles are unique between patients with IGM and LM. Inter-patient variability and polymicrobial IGM pus samples cannot implicate specific genus or species as an infectious cause for IGM.

Clinical characteristics and microbiota analysis of 44 patients with granulomatous mastitis

Introduction

Granulomatous mastitis (GM) is a chronic inflammatory breast disease. In recent years, the role of Corynebacterium in GM onset has received more and more attention. This study aims to detect the dominant bacterium in GM patients and analyze the association between clinical characteristics and infectious factors.

Methods

In this study, 88 samples from 44 GM patients, six acute lactation mastitis (ALM) patients, and 25 non-inflammatory breast disease (NIB) patients were divided into a GM pus group, a GM tissue group, an ALM pus group, and a NIB tissue group; then, 16S ribosomal DNA sequencing was used to explore their microbiota. The clinical data of all 44 GM patients were also retrospectively collected and analyzed to determine their relationship with infection.

Results

The median age of the 44 GM patients was 33 years, and 88.6% of patients had primary-onset cases, while 11.4% were recurrences; additionally, 89.5% of patients were postpartum and 10.5% were nulliparous. The serum prolactin level was abnormal in nine patients (24.3%). Samples from 15 GM patients (34.1%) had a Corynebacterium abundance of >1% (1.08-80.08%), with eight (53.3%) displaying an abundance of >10%. Corynebacterium was the only genus with significant differences between the GM pus group and the other three groups (p < 0.05). Corynebacterium kroppenstedtii was the predominant Corynebacterium species. Among clinical characteristics, a statistical difference in breast abscess formation was observed according to Corynebacterium abundance in Corynebacterium-positive and- negative patients (p < 0.05).

Discussion

This study explored the relationship between Corynebacterium infection and GM, compared the clinical characteristics between Corynebacterium-positive and- negative patients, and provided support for the role of Corynebacterium species-in particular, C. kroppenstedtii-in the pathogenesis of GM. The detection of Corynebacterium can predict GM onset, especially in patients with high prolactin levels or a history of recent lactation.

Differential expression profiles of miRNA in granulomatous lobular mastitis and identification of possible biomarkers

The etiology and pathogenesis of granulomatous lobular mastitis (GLM) remain largely elusive and the expression levels and regulatory roles of microRNAs (miRNAs or miRs) in GLM have remained mostly undetermined. In the present study, the miRNAs that were differentially expressed in breast biopsy samples from patients with GLM and normal tissue adjacent to fibroadenoma were analyzed, a comprehensive differential expression profile of miRNAs was provided and potential biomarkers were screened out. The expression profile of miRNAs was determined by high-throughput sequencing in the tissues of patients with GLM and healthy controls. Significantly differentially expressed miRNAs were screened by threshold setting and cluster analysis and their target genes were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, circulating differentially expressed miRNAs between the GLM and control groups were further analyzed by reverse transcription-quantitative PCR (RT-qPCR). A total of 31,077 miRNAs were detected by high-throughput sequencing. By using the cutoff criteria of |log2 fold change|>2.5 and q<0.001, 13 miRNAs that were indicated to be GLM biomarkers were screened out. The expression levels of these 13 miRNAs in the GLM group were higher than those in the control group. GO and KEGG enrichment analyses suggested that the occurrence and development of GLM may be associated with autoimmune inflammation, metabolism and pathogenic organisms. miR-451a and miR-5571-3p were confirmed to be significantly increased in the serum of patients with GLM compared with their levels in the serum of healthy volunteers, which suggests that they may be used as biomarkers of GLM. To the best of our knowledge, the present study was the first report detailing genome-wide miRNA profiling of patients with GLM compared with controls. The possible targets and pathways of GLM were evaluated by bioinformatics analysis. The present study identified 13 differentially expressed miRNAs with important theoretical significance and potential application. Furthermore, miR-451a and miR-5571-3p were verified by RT-qPCR as possible biomarkers of GLM.

Interactions between the breast tissue microbiota and host gene regulation in nonpuerperal mastitis

BACKGROUND

Nonpuerperal mastitis (NPM) causes considerable psychological distress in females, since it is difficult to diagnose and treat. A spectrum of etiological factors can lead to NPM. However, the pathogenesis of NPM remains unclear. Here, we aimed to dissect the role of host gene-microbe interactions in NPM.

METHODS

We compared the breast tissue microbiome between NPM patients and controls using 16S rRNA sequencing. We also compared the gut microbiome between NPM patients and healthy controls. Moreover, we investigated whether the breast tissue microbiome was associated with an altered gut microbiome in patients with NPM. We analyzed differentially expressed genes in inflammatory tissues of mammary gland from patients with NPM and normal mammary gland tissues from patients with benign and non-infectious breast disease by RNA-sequencing (RNA-seq). Lastly, we explored the association of specific bacterial taxa with differential expression of immune-related genes and differences in infiltrating immune cells.

RESULTS

The breast tissue microbiome from NPM and controls showed significant differences in community composition. The breast tissue shared a relatively small proportion of bacterial communities with the gut in patients with NPM. Ruminococcus (family Ruminococcaceae) of breast tissue was positively correlated with the differentially expression of immune-related genes between NPM patients and controls, including antigen processing and presentation genes (ICAM1, LGMN, THBS1, TAP1, HSPA1B and HSPA1A), cytokine receptor gene IL15RA, and chemokine gene CCN1. Rhizobium of breast tissue was negatively correlated with the differentially expression of the antigen processing and presentation gene HSPA6 between NPM patients and controls. We also found that Ruminococcus (family Ruminococcaceae), Coprococcus, and Clostridium of breast tissue positively correlated with the difference of CD8⁺ T cells between NPM patients and controls.

CONCLUSIONS

We preliminarily explored the potential role of host-microbe interactions in NPM. We demonstrate cross-talk between the breast tissue microbiome and the gut microbiome in patients with NPM. We suggest that NPM microbiome composition influences the immune microenvironment of the disease by affecting the transcriptome. This is an exploratory study and further investigation of host-microbe interactions and its potential mechanism in NPM development are warranted.

Idiopathic granulomatous mastitis - new approach in operative treatment

Introduction. Idiopathic granulomatous mastitis (GM) is described as a very rare, non-lactating, chronic mastitis that occurs primarily in women of childbearing age. Significant clinical problem related to GM is the diagnostic differentiation from breast cancer. Less advanced forms of GM can be successfully treated with limited surgical excisions and radical treatment is recommended only for the most extensive forms. Case report. First examination of the patient, by the surgeon at Oncology Institute of Vojvodina was in December 2018., when initial suspicion of breast cancer was set up. Core needle biopsy was performed and after histopathological (HP) analysis, confirmation of GM was obtained. The patient was initially offered Prednisone and Methotrexate therapy, which she refused and accepted only surgical treatment. Surgical treatment was performed few weeks after needle biopsy and consisted of performing a nipple spearing mastectomy with excision of the orifices of all fistulous ducts and their primary sutures. The HP findings of the operative specimen confirmed the diagnosis of GM. While there were no signs of dieses relapse, patient was suggested secondary reconstruction of the left breast. Twelve months after the primary operation, secondary breast reconstruction was performed with the interposition of a contoured silicone implant into a muscle pocket in a standard manner. Conclusion. Nipple spearing mastectomy with secondary breast reconstruction is aesthetically satisfactory treatment for patients with locally advanced GM.

Contamination Issue in Viral Metagenomics: Problems, Solutions, and Clinical Perspectives

We describe the most common internal and external sources and types of contamination encountered in viral metagenomic studies and discuss their negative impact on sequencing results, particularly for low-biomass samples and clinical applications. We also propose some basic recommendations for reducing the background noise in viral shotgun metagenomic (SM) studies, which would limit the bias introduced by various classes of contaminants. Regardless of the specific viral SM protocol, contamination cannot be totally avoided; in particular, the issue of reagent contamination should always be addressed with high priority. There is an urgent need for the development and validation of standards for viral metagenomic studies especially if viral SM protocols will be more widely applied in diagnostics.

A novel therapy for granulomatous lobular mastitis: Local heat therapy

Granulomatous lobular mastitis (GLM) is a chronic inflammatory breast condition that is characterized by granulomatous inflammation. GLM remains a refractory disease due to its failure to respond to routine anti-inflammatory therapies and its high recurrence rate. Thus, the present study aimed to investigate the application of local heat therapy in GLM as a potential therapeutic strategy. The results revealed that the application of local heat therapy was associated with a shortened remission time for GLM, while the remission and recurrence rates were similar to those of existing therapies. The median first remission time following local heat therapy was significantly decreased compared with that following corticosteroid therapy (5.30 months vs. 11.27 months; P<0.05). The remission rates were not significantly different between the local heat therapy (76.9%), extensive excision (90.4%) and the corticosteroid therapy (85.7%) groups (P>0.05). In addition, the recurrence rates were not statistically different between the groups (local heat therapy, 8.3%; extensive excision, 10%; and corticosteroid therapy, 10%; P>0.05). The local heat therapy showed mild adverse effects and shortened healing times compared to the other therapies; however, further confirmation is required.

Detection of Corynebacterium kroppenstedtii in Granulomatous Lobular Mastitis Using Real-Time Polymerase Chain Reaction and Sanger Sequencing on Formalin-Fixed, Paraffin-Embedded Tissues

CONTEXT.—

Associations between granulomatous lobular mastitis (GLM) and Corynebacterium kroppenstedtii have been reported since 2002, but large scale studies to assess the actual prevalence of this bacterium in GLM have not been performed.

OBJECTIVE.—

To assess the prevalence of C kroppenstedtii in GLM using real-time polymerase chain reaction and Sanger sequencing.

DESIGN.—

We analyzed formalin-fixed, paraffin-embedded tissues from 67 cases of GLM by sequential DNA amplification and sequencing to assess the rate of C kroppenstedtii detection in GLM. A retrospective analysis including patient demographics, history of pregnancy and lactation, clinical signs and symptoms, radiographic findings, histologic pattern, Gram stain results, and microbial cultures was performed on 67 cases of GLM. In addition, 10 cases of nongranulomatous breast abscess were included as controls.

RESULTS.—

C kroppenstedtii 16S rRNA SYBR real-time polymerase chain reaction was positive on formalin-fixed, paraffin-embedded tissues from 46 of 67 (68.7%) GLM cases, while all control cases were negative. Among the positive cases, the majority showed features of cystic neutrophilic granulomatous mastitis.

CONCLUSIONS.—

C kroppenstedtii was highly prevalent in GLM cases and was not found to be associated with nongranulomatous breast abscess in our study (P < .001).

Is the skin microbiota a modifiable risk factor for breast disease?: A systematic review

PURPOSE

High prevalence, unreliable risk discrimination and poor clinical outcomes are observed in malignant and benign breast diseases (BD). The involvement of microbial communities in the development of BD has become topical, and distal influences of microbial dysregulation in the breast have been well established. Despite advances, the role of the breast skin microbiota in BD remains unclear. Interactions between the skin microbiota and the underlying mucosal immune system are complex. In homeostasis, the skin offers a physical barrier protecting underlying breast tissue from skin commensals and noxious environmental triggers. Our review aims to illuminate the role of the skin microbiota in the development of BD.

METHODS

Adhering to the PRISMA protocol, a systematic review was conducted utilising the Medline and Embase search engines.

RESULTS

Through a comprehensive search of the last ten years, twenty-two studies satisfied the inclusion criteria. Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were identified as the most prevalent phyla of both breast tissue and skin in healthy controls and BD. High abundance of skin commensals, specifically some species of Staphylococcus, have been linked in breast cancer and metastases. Similarly, dysregulated microbial abundance is also seen in inflammatory and implant-associated BD. These findings raise the hypothesis that the skin microbiota plays a role in tissue homeostasis and may contribute to a range of breast pathologies. Several mechanisms of microbial transfer to underlying tissue have been proposed, including retrograde transfer through ductal systems, breakdown of the skin barrier, and migration through nipple-aspirate fluid.

CONCLUSION

Our review provides preliminary insights into the skin microbiota as a modifiable risk factor for BD. This raises opportunities for future studies in antimicrobials/probiotics as an adjunct to, or replacement of surgery; a diagnostic and/or prognostic tool for BD; and the possibility of conditioning the microbiota to manage BD.

New Insights of Corynebacterium kroppenstedtii in Granulomatous Lobular Mastitis based on Nanopore Sequencing

BACKGROUND

The etiology of granulomatous lobular mastitis (GLM) remains unknown. This study aimed to detect bacteria in GLM using Nanopore sequencing and identify the relationship between GLM and Corynebacterium kroppenstedtii.

METHODS AND MATERIALS

The bacterial detection on fresh samples (including breast pus and tissue) of 50 GLM patients using nanopore sequencing and culture methods. The bacterial detection rate of participants with different stages were compared and analyzed. Formalin-fixed and paraffin-embedded (FFPE) tissues from 39 patients were performed on Gram staining to identify Gram-positive bacilli (GPB) within lipid vacuoles. Moreover, the clinicopathological characteristics of GLM patients in different bacterial subgroups were also conducted.

RESULTS

In 50 GLM patients, the detection rate of bacteria was 78% using nanopore sequencing method, especially in the early stage of GLM (over 80%), which was significantly higher than that using culture methods (24%, p < 0.001). The dominant bacteria were Corynebacterium species (64%), especially for the Corynebacterium kroppenstedtii. The detection rate of C. kroppenstedtii in nanopore sequencing method (56%) was higher than that in culture methods (16%, p < 0.001). Gram staining positive of bacteria in 7 patients, and 5 of them were C. kroppenstedtii. Thirty-one patients (31/39, 79.5%) exhibited typical histological structure of cystic neutrophilic granulomatous mastitis (CNGM), and eighteen patients detected with C. kroppenstedtii.

CONCLUSION

Nanopore sequencing showed rapid and accurate bacteria detection over culture method in GLM patients. GLM is not sterile inflammation and closely related to C. kroppenstedtii. CNGM was associated with Corynebacterium infection, especially for C. kroppenstedtii.

Caracterización clínico-patológica y manejo de pacientes con mastitis granulomatosa crónica en un centro de alta complejidad

Introducción. La mastitis granulomatosa crónica es una enfermedad inflamatoria poco frecuente y con mayor incidencia en el sexo femenino. Su sintomatología y su presentación clínica causan gran ansiedad tanto en el paciente como en el personal médico, debido a su comportamiento similar al de la patología mamaria maligna. No hay una etiología clara ni un manejo terapéutico definido. El objetivo de este estudio fue determinar las características clínico-patológicas, el tratamiento y la evolución de las pacientes con mastitis granulomatosa, durante el periodo de estudio. Métodos. Estudio retrospectivo en el que se revisaron las historias clínicas de pacientes con diagnóstico y manejo de trastorno inflamatorio de la mama no especificado (N61X), entre enero de 2010 y diciembre de 2019. Se encontraron 236 pacientes, se excluyeron 176 por no cumplir con el diagnóstico de mastitis granulomatosa crónica o por no tener un seguimiento adecuado. Se evaluaron las características sociodemográficas, clínicas y de evolución, comparando la respuesta que se obtuvo con cada tratamiento. Resultados. Se incluyeron 60 pacientes femeninas que presentaron manifestaciones variadas. El 38,3 % (n=23) recibieron manejo antibiótico, el 30 % (n=18) fue tratado con corticoides, el 8,3 % (n=5) recibió antibióticos más corticoides y se realizó manejo expectante en el 16,6 % (n=10). El 6,6 % (n=4) de los pacientes fueron llevados a cirugía. Discusión. La mejor respuesta y la menor tasa de recidiva se encontró en las pacientes que fueron sometidas a observación y en aquellas que recibieron corticoides.

Pathogen determination from clinical abscess fluids using metagenomic next-generation sequencing

Abscesses are often clinically manifested as local necrotic tissues in various organs or systems of the human body, which is commonly caused by microbial infection. Rapid and accurate identification of pathogens from clinical abscetic samples would greatly guide a clinician to make the precise choices of the antimicrobial treatment. Here, this study aimed to investigate the application of metagenomic next-generation sequencing (mNGS) in the microbial detection of clinical samples of abscess fluids from various organs or systems. Nine patients with abscess from various organs or systems were enrolled in this study. The pathogenic bacteria in abscess fluid were detected and compared by the conventional bacterial culture and mNGS respectively. The dominant pathogens of abscess fluids in 8 cases can be found directly from mNGS, dominating over 80% of the total reads abundance of the microbiome. Although the pathogens from 6 cases detected by mNGS were consistent with that from the conventional bacteria culture method, the fastidious obligate anaerobic bacteria in 2 cases additionally detected by mNGS were not found by the conventional culture method. Moreover, complex polymicrobial infection containing Parvimonas micra in one case negatively with conventional bacterial culture were demonstrated by the mNGS method. And the mNGS method can directly reflect the diversity of microbial ecology in the abscess fluids from the different parts of the human body. Conclusively, mNGS can be used as a supplemental method for the pathogen detection of clinically abscess fluids.

Bacteria Associated with Granulomatous Lobular Mastitis and the Potential for Personalized Therapy

Granulomatous lobular mastitis (GLM), also known as idiopathic granulomatous mastitis (IGM), is a chronic inflammatory lesion of the breast. The incidence of GLM has been increasing in recent years, especially among young women. The etiologies of GLM have not been fully elucidated but are associated with autoimmunity and bacterial infection. Bacteria, especially Corynebacterium species, play important roles in GLM. In this article, we review research progress regarding the bacteriology of GLM attained with the application of several new high-throughput detection techniques. Accurate detection might be important for deepening our understanding of the pathogenesis of GLM and hold promise for personalized GLM therapy.

Factors associated with treatment duration and recurrence rate of complicated mastitis

BACKGROUND

The incidence of mastitis has increased, and this disease can lead to long antibiotic courses and complications. Here, we aimed to identify the factors associated with antibiotic duration and recurrence of complicated mastitis.

MATERIALS AND METHODS

This retrospective cohort study was conducted in a tertiary hospital in Taiwan. All hospitalized patients diagnosed with mastitis (ICD-9 code 611.0) from Jan. 1, 2012, to Dec. 31, 2016, were enrolled. Patient characteristics and clinical data were obtained from the medical charts. Recurrence was defined as mastitis within the first year after the discontinuation of antibiotics for at least 7 days.

RESULTS

In total, 214 females with a median age of 37 years old (IQR 33-45) were enrolled. A total of 148 patients (69.2%) underwent debridement, and 122 (57.0%) underwent biopsy. Histopathological examinations revealed granulation tissue in 44.6% (62/139) of the patients. Positive cultures were obtained in 65.9% (141/214) of the patients. Coagulase-negative staphylococci (64/141, 45.4%) was the most common pathogen, followed by Corynebacterium species (42/141, 29.8%). The median hospitalization length and antibiotic course were 7 (IQR 4-13) and 37 days (IQR 22-77), respectively. Three patients died of breast cancer during treatment. The recurrence rate was 18.5% (39/211). Younger age, corynebacterial infection, and pregnancy were associated with longer treatment durations (P < 0.001, 0.003, <0.001). Corynebacterial infection was associated with a 2.16-fold (95% CI: 1.11-4.20) increase in recurrence after adjusting for age.

CONCLUSION

Corynebacterial infection is associated with longer treatment courses and an increased recurrence rate of complicated mastitis. Therefore, specific treatments should be considered.

Cystic neutrophilic granulomatous mastitis: an update

Cystic neutrophilic granulomatous mastitis (CNGM) is a rare subtype of granulomatous mastitis with a highly distinct histological pattern often associated with Corynebacterium species. CNGM is characterised by suppurative lipogranulomas that are composed of central lipid vacuoles rimmed by neutrophils and an outer cuff of epithelioid histiocytes. Some of the lipid vacuoles may contain sparse, rod-shaped, gram-positive bacilli that can be easily missed or dismissed. The surrounding mixed inflammatory infiltrate contains Langhans-type giant cells, lymphocytes and neutrophils. CNGM occurs in reproductive age women with a history of pregnancy and typically presents as a palpable mass that can be painful. CNGM has many mimickers, most significantly breast carcinoma. In many cases, CNGM has significant pathological and clinical overlap with other forms of granulomatous mastitis. Given the association with Corynebacterium species, early diagnosis of CNGM is essential in offering patients the most appropriate treatment. Prolonged antibiotic therapy specifically directed to corynebacteria is required, sometimes even beyond resolution of clinical symptoms. This comprehensive review of the existing literature on CNGM describes clinical-pathological features, microbiological findings, challenges associated with the microscopic differential diagnosis, clinical implications of this diagnosis and emerging treatment options. Morphological criteria and suggested comments to convey the degree of diagnostic certainty are also proposed for standard pathology reporting.

Minimally invasive comprehensive treatment for granulomatous lobular mastitis

Objective

To describe a minimally invasive comprehensive treatment for granulomatous lobular mastitis (GLM) and compare its effect with the existing methods, particularly in terms of its recurrence rate and esthetic outcomes.

Methods

This retrospective study reviewed 69 GLM patients receiving the minimally invasive comprehensive treatment. Patients’ information, including age, clinical features, image characteristics, histopathological findings, mastitis history, treatment process, operative technique, recurrence, and esthetic effect, was evaluated.

Results

All patients were female with a median age of 32 (range 17–55) years. Hospital stays ranged from 2 to 34 days, with a median of 6 days. The shortest time for complete rehabilitation was 2 days and the longest time was 365 days, with a median of 30 days. After a median follow-up of 391 days (range 162–690), 7 patients (10.14%) relapsed. The average cosmetic score was 2.62 ± 0.57 points and was mainly related to the past treatment, especially the surgical history.

Conclusion

Minimally invasive comprehensive treatment is a new method for the treatment of GLM, ensuring a therapeutic effect while maintaining breast beauty.

Granulomatous mastitis due to coinfection with Histoplasma sp. and Paracoccidioides sp.: A case report

A 51 years old female patient with granulomatous mastitis diagnosis, was referred to the Medical Mycology Department “Dr. Dante Borelli” at the Instituto de Medicina Tropical, Universidad Central de Venezuela (IMT-UCV). Mycological diagnosis demonstrated the presence of intracellular yeast structures suggesting Histoplasma sp. and also multi-budding structures compatible with Paracoccidioides sp. To the best of our knowledge, this is the first case report of a granulomatous mastitits due to coinfection of both fungi. 2012 Elsevier Ltd. All rights reserved.

Cystic Neutrophilic Granulomatous Mastitis: A Clinicopathological Study With 16s rRNA Sequencing for the Detection of Corynebacteria in Formalin-Fixed Paraffin-Embedded Tissue

Cystic neutrophilic granulomatous mastitis (CNGM) is a histologically characterized variant of granulomatous lobular mastitis that is associated with lipophilic Corynebacterium species. It remains a largely underrecognized entity in India. Our aim was to study CNGM in the Asian Indian population and explore if 16s rRNA sequencing could be used on formalin-fixed paraffin-embedded (FFPE) tissue to identify the causative organism. We studied 24 cases with histological features of CNGM with hematoxylin and eosin, Gram, Ziehl-Neelsen, and Periodic acid-Schiff stains. Tuberculosis-polymerase chain reaction and 16s rRNA gene sequencing on DNA extracted from FFPE was attempted (N = 23). Gram-positive bacilli were seen in 20/24 cases. Routine culture with prolonged incubation yielded Corynebacterium species in 8 cases; 7 of these cases were evaluated by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for species identification. C matruchotti was identified in one case by BD Phoenix. MALDI-TOF MS identified the remaining 7 cases as C kroppenstedtii (N = 4) and C tuberculostearicum (N = 2), with no identification in one. Corynebacteria were identified by 16s rRNA sequencing on DNA extracted from FFPE in 12/23 cases using a primer targeting the V5-V6 region that was found to be more conserved in Corynebacterium species. All cases were negative for the diagnosis of tuberculosis. CNGM can be identified by routine stains. Culture using routine media with prolonged incubation is often adequate to isolate the organism. 16s rRNA sequencing on DNA extracted from FFPE tissue can help make an etiological diagnosis in some cases where only paraffin blocks are available.

Clinical study on surgical treatment of granulomatous lobular mastitis

Background

The etiology and pathogenesis of granulomatous lobular mastitis (GLM) remain unknown, with no unified evaluation criteria or standard treatments. This study aimed to assess the etiology and features of GLM, as well as the effects of surgery (lesion excision + stage I breast reconstruction; LE + BR) for GLM.

Methods

This study evaluated 178 female GLM patients retrospectively in 2006-2015. The surgery and non-surgery groups included 164 and 14 patients, respectively. All patients received conservative therapy (traditional Chinese medicine combined with regional wet compress and pus drainage). In addition, the surgery group (n=164) underwent LE + BR. Clinical data, including disease course, causes, lesion size, marital status, and treatment approaches, were assessed.

Results

Follow-up was 13-117 months. Seventy-five of the 178 patients had no overt causes (42.1%); meanwhile, 63 (35.4%) and 16 (9.0%) had congenital nipple retraction and a history of psychotropic drugs for >1 year, respectively. The surgery group showed lesions significantly shrunk (≤1 quadrant) with acute inflammation fully controlled; 8 showed recurrence, indicating a cure rate of 95.1% (156/164). In the non-surgery group, 4 cases showed relapse after 6-14 months (cure rate =71.4%; 10/14). Therefore, surgical treatment was significantly more efficient than non-surgical treatment (P=0.001). Kaplan-Meier survival curves for the two treatment types showed a significant difference in recurrence (log rank =11.84, P<0.001).

Conclusions

In GLM patients, LE + BR is safe and effective with respect to cosmetic results, recovery time, and recurrence. Successful surgery should be performed for patients whose lesions ≤1 quadrant, aim to achieve optimal GLM treatment.

Unfolding the Human Milk Microbiome Landscape in the Omics Era

Studies conducted in the last years have demonstrated that human milk represents a continuous supply of beneficial bacteria to the infant gut, which contribute to the maturation of the digestive and immune functions in the developing infant. Nevertheless, the origin of bacterial populations in milk is not fully understood yet and they have been proposed to originate from maternal skin, infant’s mouth, and (or) endogenously, from the maternal digestive tract through a mechanism involving immune cells. Understanding the composition, functions and assembly of the human milk microbiota has important implications not only for the infant gut microbiota establishment, but also for the mammary health since dysbiosis in the milk bacteria may lead to mastitis. Besides, host, microbial, medical and environmental factors may affect the composition of the human milk microbiome, with implications for the mother-infant health. Application of both culture-dependent and -independent techniques to assess the milk microbiome faces some practical limitations but, together, have allowed providing novel and complementary views on its origin, composition and functioning as summarized in this minireview. In the next future, the application of the ultimate advances in next-generation sequencing and omics approaches, including culturomics, will allow a detailed and comprehensive understanding of the composition and functions of these microbial communities, including their interactions with other milk components, expanding the opportunities to design novel microbiome-based modulation strategies for this ecosystem.

Societal Implications of the Internet of Pathogens

The growth of pathogen genomics shows no signs of abating. Whole-genome sequencing of clinical viral and bacterial isolates continues to grow in nearly exponential bounds. Reductions in cost driven by new technology have created a seamless environment for generating, sharing, and analyzing pathogen genomes. The high-resolution view of infectious disease transmission dynamics offered by analyzing whole genomes from pathogens, coupled with the genomicist ethic of widespread data sharing, has created a veritable Internet of pathogens, which inadvertently produces new threats to patient privacy and protected heath information. The health care system, and society more generally, have yet to explore the far-reaching privacy concerns raised by readily accessible pathogen genomic data. The recent use of human genomic databases, the existence of freely available alternative data and metadata sources, and lax regulation of collecting publicly available genomes to identify individuals in a criminal context raise concerning parallels about what is possible with pathogen genomics. The growing ability to ascertain culpability for infectious disease transmission at a nearly individual level could change our perspective on disease outbreaks from one based on public health to one based on individual liability. These technological breakthroughs in the absence of an understanding of potential privacy and liability issues lead to questions about the dominant paradigm of better living through pathogen genomics.

Role of Bacteriological Agents in Idiopathic Granulomatous Mastitis: Real or Not?

Objective

Granulomatous mastitis is a rare, benign, chronic inflammatory disease of the breast of unknown etiology. This study evaluated bacteriologic agents that might play a role in the etiology of granulomatous mastitis using a molecular method with a universal primer after isolating deoxyribonucleic acid (DNA) from pathology specimens from patients diagnosed with granulomatous mastitis.

Materials and Methods

Breast biopsy material in the pathology department obtained between July 2008 and June 2013 was analyzed. The history of the granulomatous mastitis patients was examined in detail and paraffin block sections of the biopsy material were used to determine the presence of bacteria with a universal DNA primer.

Results

This study examined 45 granulomatous mastitis patients who had been diagnosed using excisional, incisional, or core biopsies. We evaluated multiple bacterial taxa, but obtained no positive result using a nucleic-acid-based assay with a universal primer.

Conclusion

The etiology of idiopathic granulomatous mastitis remains unclear. Further studies with a large number of patients should aim to identify the causative agent.

Novel selective medium for the isolation of corynebacterium kroppenstedtii from heavily colonised clinical specimens

Aims

Granulomatous mastitis due to Corynebacterium kroppenstedtii is an increasingly recognised cause of an indolent and distressing mastitis in non-lactating females. This slow-growing lipophilic organism is not reliably isolated using routine culture methods. A novel selective culture medium (CKSM) is designed to optimise the isolation of this organism from clinical specimens.

Methods

CKSM contains 10% galactose and Tween 80 (10%) to enhance the growth of C. kroppenstedtii, fosfomycin (100 µg/mL) to suppress the other bacteria, and differentiate C. kroppenstedtii from non-kroppenstedtii lipophilic corynebacteria by esculin hydrolysis. The medium was evaluated for its ability to support the growth of C. kroppenstedtii, selection and differentiation of C. kroppenstedtii from other bacteria in non-sterile clinical specimens.

Results

C. kroppenstedtii grew as 1–2 mm colonies with black halo on CKSM within 72 hours of incubation, compared with barely visible pinpoint colonies on routine blood agars. During the four-month period of evaluation with 8896 respiratory specimens, 103 breast specimens, 1903 female genital tract specimens, 617 newborn surface swabs and 10 011 miscellaneous specimens, 186 C. kroppenstedtii were isolated, including 127 (1.4%) respiratory and 59 (0.5%) miscellaneous specimens, 184 of them were found only on CKSM. Besides the three (2.9%) positive breast specimens, 27 (1.4%) high vaginal and endocervical swabs, and 11 (1.8%) surface swabs of newborns were positive for C. kroppenstedtii.

Conclusions

CKSM is a useful addition to routine agar media for the isolation of C. kroppenstedtii, and will be helpful for studying the epidemiology and transmission of this unusual Corynebacterium causing granulomatous mastitis.

Corynebacterium kroppenstedtii Is an Emerging Cause of Mastitis Especially in Patients With Psychiatric Illness on Antipsychotic Medication

This retrospective study of patients with Corynebacterium kroppenstedtii infections revealed a predominance of mastitis and a potential association with psychiatric illnesses. At least one third of our patients with C kroppenstedtii mastitis had psychiatric illness, and >92% received antipsychotic medications. Drug-induced hyperprolactinemia may be an important modifiable risk factor in these patients.

Granulomatous Lobular Mastitis Associated with Mycobacterium abscessus in South China: A Case Report and Review of the Literature

Mycobacteria, which are known as rapidly growing bacteria, are pathogens that are responsible for cutaneous or subcutaneous infections that especially occur after injection, trauma, or surgery. In this report, we describe a species of Mycobacterium abscessus that was isolated from a breast abscess in a patient who was previously diagnosed with granulomatous lobular mastitis (GLM). This current case is the first ever presented case of GLM associated with M. abscessus documented in South China. The case presentation highlights the role of M. abscessus in GLM. The association of M. abscessus and GLM is discussed and a summary of breast infection due to Mycobacteria is given.