Breast infections - Microbiology and treatment in an era of antibiotic resistance

Carbon dots as a novel photosensitizer for photodynamic therapy of cancer and bacterial infectious diseases: recent advances

Carbon dots (CDs) are novel carbon-based nanomaterials that have been used as photosensitizer-mediated photodynamic therapy (PDT) in recent years due to their good photosensitizing activity. Photosensitizers (PSs) are main components of PDT that can produce large amounts of reactive oxygen species (ROS) when stimulated by light source, which have the advantages of low drug resistance and high therapeutic efficiency. CDs can generate ROS efficiently under irradiation and therefore have been extensively studied in disease local phototherapy. In tumor therapy, CDs can be used as PSs or PS carriers to participate in PDT and play an extremely important role. In bacterial infectious diseases, CDs exhibit high bactericidal activity as CDs are effective in disrupting bacterial cell membranes leading to bacterial death upon photoactivation. We focus on recent advances in the therapy of cancer and bacteria with CDs, and also briefly summarize the mechanisms and requirements for PSs in PDT of cancer, bacteria and other diseases. We also discuss the role CDs play in combination therapy and the potential for future applications against other pathogens.

Bacteriological characteristics of primary breast abscesses in patients from the community in the era of microbial resistance

Objective

The aim of this study is to evaluate the etiological profile and antimicrobial resistance in breast abscess cultures from patients from the community, treated at a public hospital located in Porto Alegre, Brazil.

Methods

This is an retrospective cross-sectional study that evaluated the medical records of patients with bacterial isolates in breast abscess secretion cultures and their antibiograms, from January 2010 to August 2022.

Results

Based on 129 positive cultures from women from the community diagnosed with breast abscesses and treated at Fêmina Hospital, 99 (76.7%) of the patients had positive cultures for Staphylococcus sp, 91 (92%) of which were cases of Staphylococcus aureus. Regarding the resistance profile of S. aureus, 32% of the strains were resistant to clindamycin, 26% to oxacillin and 5% to trimethoprim-sulfamethoxazole. The antimicrobials vancomycin, linezolid and tigecycline did not show resistance for S. aureus.

Conclusion

Staphylococcus aureus was the most common pathogen found in the breast abscess isolates during the study period. Oxacillin remains a good option for hospitalized patients. The use of sulfamethoxazole plus trimethoprim should be considered as a good option for use at home, due to its low bacterial resistance, effectiveness and low cost.

Breast infections: A review of current literature

Breast infections are common, affect women of all ages, and are associated with significant morbidity. Despite overall prevalence, treatment varies significantly based on provider or institution and no central treatment guidelines exist to direct the management of breast infections. This article provides a summary of the current trends in management of breast infections. The etiology, epidemiology, risk factors, presentation, diagnosis, and treatment of mastitis and breast abscesses (and their relative subdivisions) are explored based on the current literature. Trends in microbiology are reviewed and an approach to antibiotic coverage is proposed. Overall, there is a lack of randomized-controlled trials focused on the treatment of breast infections. This has resulted in an absence of clinical practice guidelines for the management of breast abscesses and variable practice patterns. The development of best-care protocols or pathways could provide more uniformity in care of breast infections.

Evaluation of pathogen distribution and antimicrobial resistance in breast plastic surgery infection

BACKGROUND

The demand for mammaplasty has increased in recent years, and infection remains one of the common and serious post-operative complications. In this study, we analyzed the pathogen distribution and antibiotic susceptibility of breast plastic surgery infections, and compared the differences in pathogenic species between surgical procedures.

METHODS

The number of each species was counted in the microbial samples of breast plastic surgery infections in Plastic Surgery Hospital of Chinese Academy of Medical Sciences from January 2011 to December 2021. The in vitro antibiotic sensitivity testing data were analyzed using WHONET 5.6 software. The surgical techniques, the period of infection, and other details were gathered in accordance with the clinical data.

RESULTS

There were a total of 42 cases included, and 43 different types of pathogenic bacteria, mostly gram-positive bacteria, were found. CoNS (13/43) and Staphylococcus aureus (22/43) made up the majority. The most prevalent of the five Gram-negative bacteria was Pseudomonas aeruginosa. Results of drug sensitivity tests indicate that S. aureus is highly sensitive to vancomycin, cotrimoxazole, and linezolid, whereas CoNS is highly sensitive to vancomycin, linezolid, and chloramphenicol. Both of these bacteria show high resistance to erythromycin and penicillin. Breast augmentation, breast reconstruction, and breast reduction surgery were the most frequently associated breast surgery procedures in this study with infections, with the highest number of infections occurring following breast augmentation with fat grafting, breast reduction surgery, and breast reconstruction with autologous tissue. Various breast plastic surgery procedures have different common pathogens of infection, but the most prevalent are CoNS and S. aureus. Additionally, the majority of the infections in this study were in the early stages.

CONCLUSIONS

Gram-positive bacteria were the predominant cause of breast plastic surgery infections, and the types of infection strains, the period of infection onset, and the antibiotic susceptibility of prevalent strains varied between breast plastic procedures.

Breaking the Barrier: A Study on Multi-drug Resistance in Breast Abscess at an Academic Malaysian Hospital

BACKGROUND

In recent years, the increase in antibiotics usage locally has led to a worrying emergence of multi-drug resistant organisms (MDRO), with the Malaysian prevalence rate of methicillin-resistant Staphylococcus aureus (MRSA) ranging from 17.2 to 28.1% between 1999 and 2017. A study has shown that 7% of all non-lactational breast abscesses are caused by MRSA. Although aspiration offers less morbidities compared to surgical drainage, about 20% of women infected by MRSA who initially underwent aspiration subsequently require surgical drainage. This study is conducted to determine the link between aetiology, antimicrobial resistance pattern and treatment modalities of breast abscesses.

METHODS

Retrospective study of reviewing microbiology specimens of breast abscess patients treated at Universiti Malaya Medical Centre from 2015 to 2020. Data collected from microbiology database and electronic medical records were analysed using SPSS V21.

RESULT

A total of 210 specimens from 153 patients were analysed. One-fifth (19.5%) of the specimens isolated were MDRO. Lactational associated infections had the largest proportion of MDR in comparison to non-lactational and secondary infections (38.5%, 21.7%, 25.7%, respectively; p = 0.23). Staphylococcus epidermidis recorded the highest number of MDR (n = 12) followed by S. aureus (n = 8). Adjusted by aetiological groups, the presence of MDRO is linked to failure of single aspirations (p = 0.554) and significantly doubled the risk of undergoing surgical drainage for resolution (p = 0.041).

CONCLUSION

MDR in breast abscess should be recognised as an increasing healthcare burden due to a paradigm shift of MDRO and a rise of resistance cases among lactational associated infection that were vulnerable to undergo surgical incision and drainage for resolution.

Inflammatory Lesions of the Breast

CONTEXT.—

Inflammatory lesions of the breast are rare but not infrequently pose problems both clinically and morphologically, particularly on needle core biopsies. These lesions range from acute inflammatory conditions to chronic lymphoplasmacytic and lymphohistiocytic to granulomatous inflammatory diseases.

OBJECTIVE.—

To provide a comprehensive overview of inflammatory lesions of the breast, with etiopathogenesis and clinical, radiologic, and pathologic features as well as differential diagnostic considerations, clinical management, and prognosis.

DATA SOURCES.—

The existing literature in the English language, including original research articles and review articles describing inflammatory lesions of the breast.

CONCLUSIONS.—

Inflammatory lesions of the breast are characterized by a wide variety of clinical, radiologic, and morphologic features. The histopathologic differential diagnosis often includes a neoplastic process requiring ancillary studies and correlation with clinical and radiologic findings. Although most specimens display nonspecific findings precluding a definitive pathologic diagnosis, pathologists have a unique opportunity to play a crucial role in identifying key histologic features suggestive of certain entities, such as cystic neutrophilic granulomatous mastitis, immunoglobulin (Ig) G4 mastitis, or squamous metaplasia of lactiferous ducts, in the right clinical and radiologic context, and thereby guiding optimal and timely clinical management. The information presented herein will be helpful to practicing anatomic pathologists and pathology trainees in becoming more familiar with specific morphologic features and overcoming differential diagnostic challenges related to pathology reporting of inflammatory lesions of the breast.

Dissemination of methicillin-resistant Staphylococcus aureus USA300 ST8/PVL- positive in breast infections in a Brazilian region

We aimed to analyze the molecular epidemiology of 46 methicillin-resistant Staphylococcus aureus (MRSA) isolated from breast infections. The USA300 lineage carrying SCCmecIVa, arginine catabolic mobile element, t008, ST8, and Panton-Valentine leukocidin genes was predominant (93%). This is the first study that describes the spread of the USA300 methicillin-resistant Staphylococcus aureus clone in breast infections in Brazil.

Microbiology of breast abscesses

INTRODUCTION

Treatment of breast abscesses is based on drainage and antibiotic therapy directed at the bacteria causing the infection. The aim of this study was to know the etiological agents of breast abscesses.

METHODS

Patients who had a culture-positive breast abscess between September 2015 and January 2020 were included in the study. Culture results were consulted in the laboratory database. It was collected from medical records if the patients presented the following risk factors: breastfeeding, diabetes or smoking. Abscesses secondary to surgical wound infection were excluded.

RESULTS

Sixty patients were included, 58 women and 2 men. Staphylococcus aureus was the most frequent agent in lactating women. Anaerobic bacteria were isolated in 28 (61%) of 46 abscesses in non-lactating patients. In non-lactating patients, the frequency of anaerobes in abscesses was lower in diabetics than in the rest (0/5 vs 26/38; P = .013). In non-lactating and non-diabetic patients, the proportion of abscesses with anaerobes was higher in smokers than in non-smokers (21/24 vs 5/14; P = .003). Aerobic gram-positive cocci were the most frequent agents in diabetics.

CONCLUSION

Anaerobes were the most frequent agents, followed by S. aureus. The etiology of breast abscesses varied with the risk factors studied.

Photodynamic Anti-Bacteria by Carbon Dots and Their Nano-Composites

The misuse of many types of broad-spectrum antibiotics leads to increased antimicrobial resistance. As a result, the development of a novel antibacterial agent is essential. Photodynamic antimicrobial chemotherapy (PACT) is becoming more popular due to its advantages in eliminating drug-resistant strains and providing broad-spectrum antibacterial resistance. Carbon dots (CDs), zero-dimensional nanomaterials with diameters smaller than 10 nm, offer a green and cost-effective alternative to PACT photosensitizers. This article reviewed the synthesis methods of antibacterial CDs as well as the recent progress of CDs and their nanocomposites in photodynamic sterilization, focusing on maximizing the bactericidal impact of CDs photosensitizers. This review establishes the base for future CDs development in the PACT field.

Non-lactational Infectious Mastitis in the Americas: A Systematic Review

Background: Non-lactational infectious mastitis (NLIM) is an inflammatory breast disease with broad clinical presentation. Inadequate treatment can lead to chronic infections that cause breast deformities. NLIM information is limited, especially in the Americas. A systematic review and meta-analysis have been conducted here. Methods: Literature search was conducted in three databases (Lilacs, PubMed, and Scielo) on NLIM cases in the Americas. Demographic, epidemiological, clinical, radiological, and laboratory data were extracted. The main characteristics and results were also compared according to the country's gross national income. Results: A total of 47 articles were included, resulting in 93 cases. The etiological agent was described in 86 (92.5%) patients. Bacteria were the most prevalent etiology (73; 84.8%). Amongst bacterial diagnoses, more frequent cases were Mycobacterium tuberculosis (28; 38.4%); Corynebacterium spp. (15; 20.5%); non-tuberculous mycobacteria (13; 17.8%). The cases were reported in eight different countries, with the USA being the country with the highest number of cases (35; 37.6%). Patients from high-income countries group presented a shorter diagnostic time when compared to low, low-middle, and upper-middle-income countries. A greater number of radiographic studies with pathological findings were described in high-income countries. Conclusion: Non-lactational infectious mastitis is a complex public health problem with diagnostic and treatment challenges. Hence, multi-professional approach-based additional studies are recommended on its epidemiology, diagnosis, treatment, and control.

Microbiology of breast abscesses

INTRODUCTION

Treatment of breast abscesses is based on drainage and antibiotic therapy directed at the bacteria causing the infection. The aim of this study was to know the etiological agents of breast abscesses.

METHODS

Patients who had a culture-positive breast abscess between September 2015 and January 2020 were included in the study. Culture results were consulted in the laboratory database. It was collected from medical records if the patients presented the following risk factors: breastfeeding, diabetes or smoking. Abscesses secondary to surgical wound infection were excluded.

RESULTS

Sixty patients were included: 58 women and 2 men. Staphylococcus aureus was the most frequent agent in lactating women. Anaerobic bacteria were isolated in 28 (61%) of 46 abscesses in non-lactating patients. In non-lactating patients, the frequency of anaerobes in abscesses was lower in diabetics than in the rest (0/5 vs 26/38; P=.013). In non-lactating and non-diabetic patients, the proportion of abscesses with anaerobes was higher in smokers than in non-smokers (21/24 vs 5/14; P=.003). Aerobic gram-positive cocci were the most frequent agents in diabetics.

CONCLUSION

Anaerobes were the most frequent agents, followed by S.aureus. The etiology of breast abscesses varied with the risk factors studied.

Carbon Nanodots in Photodynamic Antimicrobial Therapy: A Review

Antibiotic resistance development in bacteria is an ever-increasing global health concern as new resistant strains and/or resistance mechanisms emerge each day, out-pacing the discovery of novel antibiotics. Increasingly, research focuses on alternate techniques, such as antimicrobial photodynamic therapy (APDT) or photocatalytic disinfection, to combat pathogens even before infection occurs. Small molecule "photosensitizers" have been developed to date for this application, using light energy to inflict damage and death on nearby pathogens via the generation of reactive oxygen species (ROS). These molecular agents are frequently limited in widespread application by synthetic expense and complexity. Carbon dots, or fluorescent, quasi-spherical nanoparticle structures, provide an inexpensive and "green" solution for a new class of APDT photosensitizers. To date, reviews have examined the overall antimicrobial properties of carbon dot structures. Herein we provide a focused review on the recent progress for carbon nanodots in photodynamic disinfection, highlighting select studies of carbon dots as intrinsic photosensitizers, structural tuning strategies for optimization, and their use in hybrid disinfection systems and materials. Limitations and challenges are also discussed, and contemporary experimental strategies presented. This review provides a focused foundation for which APDT using carbon dots may be expanded in future research, ultimately on a global scale.