Fournier's gangrene (FG) is a specific form of necrotizing fasciitis that involves the soft tissues of the genital, perineal, and perianal regions. It is an uncommon disease that can affect people of any age and rapidly progress to a life-threatening stage. The incidence is reported to be 1.6 cases per 100,000 men per year and remains steady after the age of 50 at 3.3 cases per 100,000 men (1). Early diagnosis and emergency intervention are mandatory owing to the rapid rate of fascial necrosis. However, non-specific symptoms at the early stage and lack of awareness among clinicians may delay diagnosis, hence, leading to a miss of the best time for intervention. As the infection progresses, typical symptoms may present, such as blistering, purulent discharge, crepitation, or necrosis, accompanied by systemic inflammatory response syndrome, sepsis, shock, or multiple organ dysfunction syndrome (MODS), leading to death. The infection can spread to distal regions, such as the abdominal wall, ischiorectal fossa, hip, and thigh through the fascial plane. Currently, the mortality remains at 20%–30% (2, 3). Negative-pressure wound therapy (NPWT) is an effective wound management technique that is widely used for almost all types of wounds. This study aimed to summarize the characteristics of FG and evaluate the effects of NPWT.

This retrospective case-control study enrolled patients with FG treated at our department between May 2010 and June 2022. Data were obtained from medical records. The diagnosis was based on clinical findings (necrosis of the skin and/or fascia, gray discolored fascia, “dishwater fluid,” lack of bleeding, and tissue resistance of the fascial layer). The extent of infection that limited itself to the genital, perineal, or perianal regions was considered as “localized;” otherwise it was considered as “diffused”. Patients were divided into two groups based on wound management: group A comprised patients treated with NPWT and group B comprised patients treated with conventional dressing. This study was approved by the Institutional Human Investigations Committee.

Thirty-six patients were enrolled in the study. Patient characteristics and diseases are shown in Table 1. Diabetes mellitus (DM) was the most common comorbidity (53%). Twenty-eight patients were transferred to our department from other hospitals, 12 of whom had undergone incision and drainage. The predominant etiologies were perianal (64%) and external genital (31%) infections. The infection had spread to the distal part beyond the genital, perineal, or perianal regions in 24 cases, including the lower or lateral abdominal wall, inguinal region, thigh, ischiorectal fossa, and hip.

Pathogens were identified in 34 (95%) patients. The details of the 49 bacterial strains cultured were listed in Table 2. Enterobacteriaceae, Enterococcus, and Staphylococcus haemolyticus were the most common causative pathogens. The resistance rate of gram-negative bacilli to third-generation cephalosporins was 35%. Vancomycin-resistant gram-positive bacteria were not found, but all S. haemolyticus isolates were methicillin resistant.

Colostomy and suprapubic cystostomy was performed in 10 and 2 patients, respectively. The mortality rate was 8%. Delayed primary closure, secondary intention, or split-thickness skin grafts (STSG) were applied for wound reconstruction.

FG is a fulminant and life-threatening disease that requires timely and standardized intervention. The initial symptoms vary; therefore, FG is easily misdiagnosed as cellulitis or erysipelas. Once typical symptoms appear, the infection is usually severe or has already spread to the distal regions. Pathogens play an important role in the development of FG (5). We enrolled a relatively large number of patients with FG, summarized their characteristics, provided the spectrum of pathogens, shared treatment experiences, and evaluated the effects of NPWT.

DM is one of the main predisposing factors, apart from immunosuppression, malignancy, and chronic steroid use (5). Local intravenous drug injection can also be the predisposing factor in rare cases (6). Concordant with previous studies, 53% of patients in the present study had DM. A meta-analysis showed that mortality due to FG is associated with DM (7). In the present study, the prevalence of DM in patients who died (67%) was higher than that in patients who survived (52%); however, the relatively small number of patients who died precludes statistical conclusions from being drawn. Perianal and external genital infections were the predominant etiologies, and the infection had spread to the distal parts in most cases (67%). This finding was consistent with the anatomical features and pathogenesis of FG. Perianal sources of infection can spread to the perineal fascia through perianal space, and fascial systems of the penis, scrotum, perineum, and abdominal wall are all connected. Therefore, perianal abscess may involve the Colles fascia, and the infection may spread to the penis and scrotum via Buck's and Dartos fascia, or to the anterior abdominal wall via Scarpa's fascia, or vice versa. Therefore, to avoid misdiagnosis or delayed diagnosis, clinicians should always consider the possibility of perianal or external genital infections progressing to FG in the daily work, especially for patients with DM. Patients are recommended to routinely undergo LRINEC scoring, closely observe the wound, and maintain timely communication.

An early diagnosis of FG is challenging, but the principles of treatment are clear and include aggressive debridement, anti-infection treatment, and supportive treatment (5, 7). Furthermore, the principles of anti-infection treatment depend on empirical broad-spectrum antibiotic coverage before pathogen identification. Therefore, it is imperative to understand the characteristics of these pathogens. Some studies suggested polymicrobial infection as the predominant type (5, 8, 9), but another study identified predominant incidence of monomicrobial gram-negative organisms in southwestern China (10). Nevertheless, Escherichia coli is the most frequently isolated microorganism (2, 9, 10). The generally accepted and recommended empirical antibiotic therapy includes aminoglycosides, metronidazole or clindamycin, and third-generation cephalosporin (5, 9). In the present study, the incidence of monomicrobial infections was approximately equal to that of polymicrobial infections. Escherichia coli and Klebsiella pneumoniae were the most common gram-negative, causative pathogens, whereas Enterococcus faecalis, Enterococcus faecium, and Staphylococcus haemolyticus were the most common gram-positive, causative pathogens. These findings are consistent with the predominant etiology of FG. The proportion of resistant bacteria was high; the resistance rate of gram-negative bacilli to third-generation cephalosporins was 35%, and all cases with Staphylococcus haemolyticus were methicillin resistant. Therefore, considering the drug resistance and severity of FG, carbapenem and vancomycin were used as empirical antibiotic therapies at our department. We believe that empirical antibiotic therapy in different regions should be consistent with the characteristics of the pathogens. Furthermore, although fungal infections have rarely been reported in the literature, fungal smears should be indicated to clarify the possibilities of fungal infections.

As a series of debridement procedures are normally required, an appropriate method for wound management should be applied. For conventional dressing treatment, frequent dressing changes, difficulty in timely and adequate control of exudate, and limited mobility are disadvantages. However, NPWT can create a controlled and closed negative-pressure environment. By continuously removing the wound exudate, reducing the wound area, increasing blood perfusion, and stimulating angiogenesis, it can effectively promote wound healing (11). Owing to these advantages, NPWT has been widely used to treat various types of wounds. In the present study, NPWT significantly reduced the number of operations and shortened wound healing time than conventional dressing treatment. Moreover, NPWT can effectively fix grafted skin on the surface of irregular wounds, such as the penis or scrotum. Patients can carry the device while moving in the ward, ensuring increased compliance to the treatment. However, NPWT cannot replace surgical debridement as a wound management technique as inappropriate use can aggravate infection. Colostomy is recommended for patients with anal fistulas or severe perianal involvement, making NPWT feasible. Hyperbaric oxygen therapy (HBOT) is also an effective adjuvant therapy for FG, and NPWT combined with HBOT shows advanced wound healing with a high efficiency rate (12). However, the main reason hampering the use of HBOT is the poor availability of the devices.

The present study has some limitations. First, as this was a single-center retrospective study, the applicability of the findings may be limited. However, the cohort size was relatively larger than that of other single-center studies. Thus, for the possible differences in the pathogenic spectrum, we also proposed relevant principles. Second, as several patients were transferred from other hospitals, some initial laboratory parameters were unavailable and previous treatment may have caused changes in the laboratory test results. However, owing to the low incidence of FG and difference in medical capacity, this phenomenon cannot be avoided.

Clinicians should always consider the possibility of perianal or external genital infections progressing to FG in the daily work, especially for patients with DM. Enterobacteriaceae, Enterococcus, and Staphylococcus haemolyticus were the most common causative agents. NPWT is an effective adjuvant therapy for wound management, with fewer operations and shorter wound healing times.