A Rare Case Report of Skin Infection Caused by Nocardia brasiliensis in an HIV Patient.

BACKGROUND: In October 2023, our hospital confirmed a case of a patient with HIV with concurrent infection with Nocardia brasiliensis. A patient with HIV developed a lump on the surface of the dorsum of his left hand without any obvious cause. He used a nail clipper to trim it. Due to improper disinfection and treatment methods, the condition worsened, and he subsequently sought medical attention at our hospital. A series of clinical laboratory tests were conducted based on the patient's medical history, symptoms, and signs. Based on the test results, a reasonable clinical treatment plan was adopted, ultimately achieving satisfactory treatment outcomes for the patient. METHODS: Clinical implementation of pus bacterial culture and identification (matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry, MALDI-TOF MS), serum anti HIV detection, and Treponema pallidum antibody detection. Additional related auxiliary examinations: blood routine, liver function, kidney function, CRP, electrolytes. RESULTS: Blood routine and CRP (venous blood): White blood cell count 16.00 x 109/L, total number of lymphocytes 3.73 x 109/L, total monocyte count 1.66 x 109/L, total number of neutrophils 10.37 x 109/L, total number of basophils 0.10 x 109/L, average platelet volume 8.8 fL, whole blood high-sensitivity C-reactive protein 46.44 mg/L, urine routine: protein+-. Liver function test: Albumin 37.7 g/L, aspartate aminotransferase 55.5 U/L, alanine aminotransferase 63.7 U/L, blood lipid test: triglycerides 2.22 mmol/L, high-density lipoprotein cholesterol 0.77 mmol/L, coagulation function test: fibrinogen test 5.69 g/L, lymphocyte subgroup analysis: T4/T8 cell ratio 0.78, total mature T cell count 2.501 x 109/L, T8 cell count 1.351 x 109/L, B cell count 0.574 x 109/L. Serum pathogen test: anti HIV positive, Treponema pallidum antibody 214.70 IU/mL, unheated serum reactive hormone test positive (1:8). Gram staining of pus: a large number of Gram positive bacteria were found, arrange in a branching form, weak acid-fast staining: positive, pus culture and bacteria identified (MALDI-TOF MS): Nocardia brasiliensis. Clinical treatment includes trimethoprim/sulfamethoxazole 800 mg/160 mg po q12 hours, local wet compress with Baiduobang ointment, and abscess incised and drained. Seven days later, the patient had a circular ulcer on the left back without any new pustules. Slightly elevated skin temperature, no tenderness, and no purulent or bloody secretions. His condition had improved and he was discharged. Follow up infectious disease specialist hospitals treat HIV, syphilis, and other related diseases. CONCLUSIONS: Patients with HIV are prone to various types of infections, even rare bacteria, as their immune function decreases. At present, there are few reports about a patient with HIV with concurrent infection with Nocardia brasiliensis. This case can provide reference for clinical diagnosis and treatment of related diseases in the future. In addition, with the popularity of new identification methods such as mass spectrometry, laboratories should pay attention to traditional staining methods and use microscopes to detect pathogens.

Tuberculosis or Nontuberculosis? A Case of Mycobacterial Skin Infection.

Bacteria other than Mycobacterium tuberculosis and Mycobacterium leprae are known as nontuberculous mycobacteria (NTM), and the frequency of clinically symptomatic forms is increasing day by day. Mycobacterium fortuitum, a rapidly reproducing NTM, causes various clinical signs such as skin soft-tissue infection, surgical site infection, and disseminated infection in immunosuppressed patients. Although progress can be made in terms of diagnosis when growth is detected in culture, it is quite difficult to distinguish between infection and contamination. There is no place for antituberculosis treatment in the treatment of M. fortuitum. Antibiotics such as quinolones, trimethoprim-sulfamethoxazole, linezolid, doxycycline, clarithromycin, azithromycin, imipenem, tigecycline, linezolid, and amikacin are recommended at least in dual combination therapy. In this case presentation, the diagnosis and treatment of a 2-year skin soft-tissue infection with M. fortuitum growth in culture will be discussed.

Cutaneous diphtheria from 2018 to 2022: an observational, retrospective study of epidemiological, microbiological, clinical, and therapeutic characteristics in metropolitan France.

The incidence of diphtheria has been rising over the past decade, particularly in its cutaneous form. A clinical review of the case series was therefore required. We reviewed the epidemiological, clinical, microbiological and therapeutic data of cutaneous diphtheria cases, in adult patients living in metropolitan France with a skin sample positive for corynebacteria of the diphtheriae complex between 2018 and 2022. Of the 132 cases identified, 63 met the inclusion criteria. The mean age was 53.8 years, 68.3% were men and 56.7% had travelled outside mainland France. Immunization rate was 44%. Lesions involved the lower limbs (86.9%), corresponded to ulcerations in 82% of cases. Two species were identified in the study: C. diphtheriae (77%) and C. ulcerans (23%). 39% were toxigenic. Other bacteria were present in 88.9% of cases: Staphylococcus aureus (54.7%) and Streptococcus pyogenes (49.1%). 17.5% of clinicians ignored the presence of Corynebacteria of the diphtheriae species complex. Clinicians seem to be unfamiliar with this disease due to under-reporting and a lack of knowledge and awareness among clinicians, and rarely mention it, which explains the frequent failure to comply with French recommendations. Clinical data are consistent with the literature. Continued epidemiological surveillance, increased vaccination coverage in high-risk populations and better information of clinicians are essential to prevent and control this preventable disease.

Mycobacterium abscessus Cutaneous Infection in the Immunosuppressed: A Case Report on an Atypical Pathogen.

Mycobacterium abscessus complex (MAbc) is a rapidly growing nontuberculous mycobacterium that represents an increasingly prevalent cause of skin infections. This report describes an atypical presentation of MAbc to heighten physician awareness of the pathogen. A 69-year-old woman with immunocompromised status presented with a 4-month history of a solitary, nonhealing ulcer on her right lower extremity after an insect bite. After no improvement following oral amoxicillin/clavulanate and topical mupirocin for the initial diagnosis of cellulitis, biopsy and culture of the lesion revealed MAbc. Microscopic examination revealed reactive cutaneous inflammation without evidence of malignancy. Acid-fast bacteria (AFB) stain was negative, and no granulomas were noted histologically. Clarithromycin and doxycycline were initiated while awaiting susceptibility testing results. Final culture showed MAbc sensitive to amikacin, cefoxitin, and clarithromycin. Unfortunately, before antibiotic therapy could be modified, the patient died. The presentation of a solitary lower-extremity ulcer is rare compared with current literature. This case occurred after a suspected insect bite rather than instrumentation. In addition, this case demonstrated negative AFB stain and absence of granulomas on histologic analysis. The patient's death did not allow for evaluation of treatment efficacy. Existing literature characterizing MAbc is sparse. Most cases present as multiple papules, nodules, and abscesses with positive AFB staining and granulomas; it is possible for deviations to exist depending on host immune status. Considering the highly drug-resistant nature of M abscessus, prompt diagnosis and treatment are crucial. For this to occur, clinicians must maintain high clinical suspicion for M abscessus infection in any chronic, nonhealing wound failing to respond to initial treatment.

[Skin disease caused by Mycobacterium marinum:a case report].

Mycobacterium marinum infection often affects the extremities, causing single or multiple skin lesions. With the improvement of molecular detection technology and the clinical application of NGS pathogen detection, the diagnosis rate of Mycobacterium marinum skin disease is gradually increasing. This article reported the case of a 54-year-old man who was stung by a marine fish and gradually developed swelling and nodules on his right hand and right upper limb. He was diagnosed with Mycobacterium marinum infection by detection of the tuberculosis resistance gene dissolution curve of the pus and the identification of the bacteria. Oral rifampicin combined with clarithromycin and minocycline was given for anti-infection treatment. During follow-up, the abscesses and nodules gradually shrank and eventually disappeared. By presenting the diagnosis and treatment of this case, the understanding of this disease among clinicians can be improved to avoid misdiagnosis and missed diagnosis.

High Therapeutic Index α-Helical AMPs and Their Therapeutic Potential on Bacterial Lung and Skin Wound Infections.

Antimicrobial peptides (AMPs) possess strong antibacterial activity and low drug resistance, making them ideal candidates for bactericidal drugs for addressing the issue of traditional antibiotic resistance. In this study, a template (G(XXKK)nI, G = Gly; X = Leu, Ile, Phe, or Trp; n = 2, 3, or 4; K = Lys; I = Ile.) was employed for the devised of a variety of novel α-helical AMPs with a high therapeutic index. The AMP with the highest therapeutic index, WK2, was ultimately chosen following a thorough screening process. It demonstrates broad-spectrum and potent activity against both standard and multidrug-resistant bacteria, while also showing low hemolysis and rapid and efficient time-kill kinetics. Additionally, WK2 exhibits excellent efficacy in treating mouse models of Klebsiella pneumonia-induced lung infections and methicillin-resistant Staphylococcus aureus (MRSA)-induced skin wound infections while demonstrating good safety profiles in vivo. In conclusion, the template-based design methodology for novel AMPs with high therapeutic indices offers new insights into addressing antibiotic resistance problems. WK2 represents a promising antimicrobial agent.

Dihydrothiazolo ring-fused 2-pyridone antimicrobial compounds treat Streptococcus pyogenes skin and soft tissue infection.

We have developed GmPcides from a peptidomimetic dihydrothiazolo ring-fused 2-pyridone scaffold that has antimicrobial activities against a broad spectrum of Gram-positive pathogens. Here, we examine the treatment efficacy of GmPcides using skin and soft tissue infection (SSTI) and biofilm formation models by Streptococcus pyogenes. Screening our compound library for minimal inhibitory (MIC) and minimal bactericidal (MBC) concentrations identified GmPcide PS757 as highly active against S. pyogenes. Treatment of S. pyogenes biofilm with PS757 revealed robust efficacy against all phases of biofilm formation by preventing initial biofilm development, ceasing biofilm maturation and eradicating mature biofilm. In a murine model of S. pyogenes SSTI, subcutaneous delivery of PS757 resulted in reduced levels of tissue damage, decreased bacterial burdens, and accelerated rates of wound healing, which were associated with down-regulation of key virulence factors, including M protein and the SpeB cysteine protease. These data demonstrate that GmPcides show considerable promise for treating S. pyogenes infections.

Cutaneous infection due to Mycobacterium marinum: A series of four cases from Kerala, India.

Mycobacterium marinum is a non-tuberculous mycobacterium which can be found in naturally occurring, non-chlorinated water sources and is a known pathogen that affects fish. In humans, M. marinum typically results in cutaneous lesions, it can occasionally lead to more invasive disorders. We discuss four cases of M. marinum-related cutaneous infections examined in a tertiary care facility. We want to draw attention to the challenges of accurately diagnosing this infection, stress the significance of having a high level of clinical suspicion in order to identify it, and discuss the available treatment choices.

Assessment of pharmacokinetics-pharmacodynamics to support omadacycline dosing regimens for the treatment of patients with acute bacterial skin and skin structure infections.

Pharmacokinetic-pharmacodynamic (PK-PD) relationships for efficacy were evaluated using data from omadacycline-treated patients with acute bacterial skin and skin structure infections (ABSSSI) enrolled in two phase 3 studies. Patients received omadacycline 100 mg intravenously (IV) every 12 hours for two doses, followed by 100 mg IV every 24 hours (q24h), with the option to switch to 300 mg oral (PO) q24h after 3 days or 450 mg PO q24h for two doses, followed by 300 mg PO q24h for a total duration of 7-14 days. Clinical response was evaluated at 48-72 hours [early clinical response (ECR)], end of treatment (EOT), and 7-14 days after EOT. Using a population pharmacokinetic (PK) model and PK data from patients with Staphylococcus aureus at baseline, omadacycline free-drug plasma area under the concentration-time curve (AUC) values were determined, and the relationships between free-drug plasma AUC:MIC ratio and dichotomous efficacy endpoints were evaluated. Using these relationships, the population PK model, simulation, and an omadacycline MIC distribution for S. aureus, mean percent probabilities of response were evaluated. Statistically significant PK--PD relationships were identified for ECR (P = 0.016 and 0.013 for optimized two- and three-group free-drug plasma AUC:MIC ratios, respectively). At an MIC value of 0.5 µg/mL, percent probabilities of model-predicted success for ECR based on the univariable PK-PD relationships using continuous and two-group free-drug plasma AUC:MIC ratio variables were 91.9 and 95.6%, respectively, for the IV-to-PO dosing regimen and 89.3 and 88.4%, respectively, for the PO-only dosing regimen. These data support for omadacycline IV-to-PO and PO-only dosing regimens for ABSSSI and an omadacycline susceptibility breakpoint of 0.5 µg/mL for S. aureus.

The bacterial profile and antibiotic susceptibility in skin and soft tissue infections at a tertiary care hospital of Quetta, Pakistan.

Objectives: To determine the bacterial profile and antibiotic susceptibility in skin and soft tissue infections among patients in a tertiary care setting. METHODS: The cross-sectional cohort study was conducted at the Centre for Advanced Studies in Vaccinology and Biotechnology, University of Balochistan, Quetta, Pakistan, from June 2021 to May 2022, and comprised bacteriainfected skin samples that were collected from the Bolan Medical Complex Hospital, Quetta, and the Sandeman Provincial Hospital, Quetta. The swab samples were immediately cultured, and positive samples were evaluated for biochemical tests, antibiotic susceptibility test and polymerase chain reaction. Data was analysed using SPSS 22. RESULTS: Of the 800 samples, 598(74.7%) tested positive for pathogenic bacteria. Staphylococcus aureus accounted for 316(39.5%) infections, followed by clostridium perfringens 18.96(2.37%), escherichia coli 120(15.12%), pseudomonas aeruginosa 98(12.25%) and klebsiella pneumoniae 44(5.5%). Among all the infected samples, 380(47.5%) belonged to males, 218(27.25%) to patients aged 5-20 years, 448(56%) to the uneducated subjects, and 462(57.87%) to patients having lower socioeconomic status. Pseudomonas aeruginosa showed the highest level of resistance against all antibiotics. Conclusion: Regular surveillance and proper use of antibiotics should be encouraged in hospitals to limit the spread of antibiotic resistance against pathogenic bacteria.

Common Skin Conditions in Children and Adolescents: Bacterial Infections.

Bacterial skin infections represent a significant health care burden. Cellulitis and erysipelas are rapidly spreading, painful, superficial skin infections, usually caused by streptococci or Staphylococcus aureus. Folliculitis is an infection of hair follicles mostly caused by S aureus. Simple folliculitis typically is self-limited. Topical benzoyl peroxide is a first-line nonantibiotic treatment. Mupirocin and clindamycin are topical antibiotic options. For treatment-resistant cases, oral cephalexin or dicloxacillin is an appropriate option. Impetigo is a common, self-limited infection in children. Bullous impetigo is caused by S aureus, and nonbullous impetigo is caused by beta-hemolytic streptococci, S aureus, or both. In most cases, topical mupirocin or retapamulin (Altabax) is effective. Oral antibiotics should be considered for household outbreaks or patients with multiple lesions. Abscesses are red, painful collections of purulence in the dermis and deeper tissues caused by S aureus or polymicrobial infections. Furuncles are abscesses of a hair follicle, whereas carbuncles involve several hair follicles. In recurrent cases of these lesions, culture of the exudate is recommended. Abscess, furuncle, and carbuncle management consists of incision and drainage. Oral antibiotics are not necessary in most cases but should be prescribed for patients with severe immunocompromise or systemic signs of infection. In bacterial skin infections, methicillin-resistant S aureus coverage should be considered for patients with infections that have not improved with treatment.

Single Intravenous Dose Dalbavancin Pathway for the Treatment of Acute Bacterial Skin and Skin Structure Infections: Considerations for Emergency Department Implementation and Cost Savings.

BACKGROUND: A pathway for the treatment of acute bacterial skin and skin structure infections (ABSSSI) with a single intravenous (IV) dose of dalbavancin was previously shown to reduce hospital admissions and shorten inpatient length of stay (LOS). OBJECTIVES: To describe pathway implementation at the emergency department (ED) and evaluate cost-effectiveness of a single-dose dalbavancin administered to ED patients who would otherwise be hospitalized to receive usual care with multidose IV antibiotics. METHODS: The dalbavancin pathway was previously implemented at 11 U.S. EDs (doi:10.1111/acem.14258). Patients with ABSSSI, without an unstable comorbidity or infection complication requiring complex management, were treated with a single dose of dalbavancin. At the emergency physicians' discretion, patients were either discharged and received outpatient follow-up or were hospitalized for continued management. A decision analytic cost-effectiveness model was developed from the U.S. healthcare's perspective to evaluate costs associated with the dalbavancin pathway compared with inpatient usual care. Costs (2021 USD) were modeled over a 14-day horizon and included ED visits, drug costs, inpatient stay, and physician visits. One-way and probabilistic sensitivity analyses examined input parameter uncertainty. RESULTS: Driven largely by the per diem inpatient cost and LOS for usual care, the dalbavancin pathway was associated with savings of $5133.20 per patient and $1211.57 per hospitalization day avoided, compared with inpatient usual care. The results remained robust in sensitivity and scenario analyses. CONCLUSION: The new single-dose dalbavancin ED pathway for ABSSSI treatment, which was previously implemented at 11 U.S. EDs, offers robust cost savings compared to inpatient usual care.

Three Cases of Non-Tuberculosis Mycobacterium Skin Infection Outbreak in Beauty Institutions.

BACKGROUND: From June 2021 to July 2021, our hospital confirmed 3 cases of Mycobacterium infection in skin abscesses. All 3 patients underwent thread embedding and weight loss surgery at the same informal beauty institution, with a history of silk protein injection. None of the patients had any other underlying diseases or surgical history. Symptoms and signs show that the disease is acute and the course of the disease is short. All patients have found subcutaneous masses in different parts of the body. In most cases, the masses show redness and swelling, and some of the masses are accompanied by tenderness, wave sensation, and rupture. After some of the masses rupture, purulent secretions can be seen. METHODS: The pus secreted by the skin lesions of the three patients were cultured to a single bacterium, which was identified by MALDI-TOF MS. Multiple locus sequence typing (MLST) was performed using three specific genes (hsp65, rpoB, and secA1) and seven housekeeping genes (argH, cya, glpK, gnd, murC, pta, and purH). The results were queried through the MLST database of Mycobacterium abscess. RESULTS: All three strains of bacteria were Mycobacterium abscess type ST279 massiliense subtype. Three antibacterial drugs including cefmetazole, amikacin, and clarithromycin were administered in combination with 5-aminolevulinic acid photodynamic therapy (ALA-PDT). After 3 - 6 months, there was no obvious redness or swelling in the surrounding tissues of the wound, and no obvious purulent secretions were observed. All patients were cured and discharged from the hospital. After a follow-up of six months, there was no recurrence of the lesions. CONCLUSIONS: Medical institutions must strictly follow infection control guidelines and take preventive measures to prevent such incidents from happening again. ALA-PDT as a combination therapy for nontuberculous Mycobacterium (NTM) skin infections can improve treatment efficacy and shorten antibiotic usage time.

A rare case of primary cutaneous Nocardia vinacea in an immunocompetent patient: A case report and a review of the literature.

The nocardiae are a complex group of bacteria belonging to the aerobic saprophytes actinomycetes. Although nocardiosis typically occurs in immunocompromised patients, infection may occasionally develop in immunocompetent patients as well. Here we describe a rare case of primary cutaneous nocardiosis due to Nocardia vinacea in an immunocompetent 79-year-old patient. Since cutaneous nocardiosis presents variably and mimics other cutaneous infections, acid-fast and Gram stainings on clinical samples are significant to obtain a rapid and presumptive diagnosis.

Reactive Microneedle Patches with Antibacterial and Dead Bacteria-Trapping Abilities for Skin Infection Treatment.

Bacterial skin infections are highly prevalent and pose a significant public health threat. Current strategies are primarily focused on the inhibition of bacterial activation while disregarding the excessive inflammation induced by dead bacteria remaining in the body and the effect of the acidic microenvironment during therapy. In this study, a novel dual-functional MgB2 microparticles integrated microneedle (MgB2 MN) patch is presented to kill bacteria and eliminate dead bacteria for skin infection management. The MgB2 microparticles not only can produce a local alkaline microenvironment to promote the proliferation and migration of fibroblasts and keratinocytes, but also achieve >5 log bacterial inactivation. Besides, the MgB2 microparticles effectively mitigate dead bacteria-induced inflammation through interaction with lipopolysaccharide (LPS). With the incorporation of these MgB2 microparticles, the resultant MgB2 MN patches effectively kill bacteria and capture dead bacteria, thereby mitigating these bacteria-induced inflammation. Therefore, the MgB2 MN patches show good therapeutic efficacy in managing animal bacterial skin infections, including abscesses and wounds. These results indicate that reactive metal borides-integrated microneedle patches hold great promise for the treatment of clinical skin infections.

Skin and Soft Tissue Actinomycosis in Children and Adolescents.

BACKGROUND: Pediatric actinomycosis studies are limited to case reports or small case series. In this retrospective cohort study, we aimed to describe characteristics of skin and soft tissue actinomycosis in adolescents and children. METHODS: We conducted the study from January 2019 to December 2022, including patients ≤21 years of age with at least 1-year follow-up data. All clinical cultures obtained under sterile conditions with Actinomyces growth were included. RESULTS: One hundred four patients met inclusion criteria; median age 19 (interquartile range: 17-20) years, 68.3% female, 46.2% Black and 47.1% Hispanic. The median antibiotic treatment duration was 10 (7-10) days, and majority of patients received treatment with non-first-line Actinomyces antibiotics. Infectious disease consultation was requested for only 7 patients during their initial skin and soft tissue actinomycosis treatment. One-third of the patients with skin and soft tissue actinomycosis had documented recurrence within a median of 10 (interquartile range: 6-16) months of the initial episode. Monobacterial culture growth (85.7% vs. 63.8%, P = 0.02), patients with body mass index >25 (75% vs. 52.6%, P = 0.04) and patients with prior abscess in the same area (18.8% vs. 51.4%, P = 0.001) were significantly higher in patients with recurrent actinomycosis compared to the nonrecurrent group. In a univariate logistic regression model, they were found to be significantly associated with recurrence; monobacterial growth [odds ratio (OR): 3.4; 95% confidence interval (CI): 1.2-9.9], body mass index >25 (OR: 2.7; 95% CI, 1.1-7.0) and prior abscess (OR: 4.6; 95% CI: 1.9-11.2). CONCLUSIONS: Our study results highlight the importance of considering Actinomyces species in skin and soft tissue infections, especially in recurrent ones, and risk factors for recurrence. Suboptimal antibiotic utilization, very low numbers of consultations with infectious diseases and high recurrence rate suggest that providers should be informed and updated regarding this rare but hard-to-treat infection.

In vitro activity of ceftazidime-avibactam against gram-negative bacteria in patients with bacteremia and skin and soft-tissue infections in Colombia 2019-2021.

OBJECTIVES: Ceftazidime-avibactam (CAZ-AVI) is an option for infections caused by MDR gram-negative bacilli. In this study, we aimed to analyze the in vitro antimicrobial activity of CAZ-AVI and other antimicrobial agents against gram-negative bacilli that were collected in Colombia between 2019 and 2021 from patients with bacteremia and skin and soft-tissue infections (SSTIs). METHODS: A total of 600 Enterobacterales and 259 P. aeruginosa strains were analyzed. The phenotypic resistance of isolates, particularly non-susceptibility to meropenem, multidrug-resistant (MDR) isolates, and difficult-to-treat (DTR) P. aeruginosa, was evaluated according to CLSI breakpoints. RESULTS: Enterobacterales had the most susceptibility to CAZ-AVI (96.5 %) and tigecycline (95 %). Tigecycline and CAZ-AVI were the antimicrobial agents with the most in vitro activity against carbapenem-resistant Enterobacterales (CRE). CAZ-AVI was the antimicrobial treatment with the most activity against P. aeruginosa. CONCLUSIONS: Tigecycline and CAZ-AVI were the antimicrobial agents with the most activity against CRE and MDR Enterobacterales. For P. aeruginosa, CAZ-AVI was the antimicrobial treatment with the most in vitro activity.