Monomicrobial Pseudomonas necrotizing fasciitis: A case of infection by two strains and a review of 37 cases in the literature

Monomicrobial Necrotizing Fasciitis and Sepsis Caused by Pseudomonas aeruginosa and Pseudomonas fluorescens: A Series of Ten Cases

Monomicrobial necrotizing fasciitis caused by Pseudomonas species is a rare infection. The purpose of this study was to elucidate the specific characteristics and clinical outcomes of necrotizing fasciitis caused by Pseudomonas aeruginosa and Pseudomonas fluorescens. Ten patients with monomicrobial necrotizing fasciitis caused by Pseudomonas species were retrospectively reviewed over an 8-year period. Differences in mortality, patient characteristics, clinical presentations, laboratory data, and clinical outcomes were compared between the death and the survival groups. Two patients died with the mortality rate of 20%. Pseudomonas aeruginosa accounted for 9 patients and Pseudomonas fluorescens for one patient. The most common comorbidity is type 2 diabetes mellitus in 5 patients. We found the death patients had lower albumin level and higher counts of band forms of leukocytes than those of the survival patients. Monomicrobial necrotizing fasciitis caused by Pseudomonas species needs emergent surgical intervention and aggressive intensive care due to high mortality rate. We reported the first case of monomicrobial necrotizing fasciitis with Pseudomonas fluorescens. Severe hypoalbuminemia and increased counts of banded leukocytes in initial laboratory presentations can be considered as poor prognostic factors.

Skin manifestations of Pseudomonas aeruginosa infections

PURPOSE OF REVIEW

Pseudomonas aeruginosa is an opportunistic pathogen with considerable morbidity and mortality, particularly in vulnerable hosts. Skin manifestations are common, either representing local inoculation or secondary skin seeding following bloodstream infections. As patients with various predisposing conditions are expanding, we sought to review the most recent published evidence regarding epidemiology, risk factors and diagnosis of skin manifestations of P. aeruginosa.

RECENT FINDINGS

New data exist on epidemiology and diagnosis of skin infections; systemic infections are impacted by multidrug-resistance issues and host immune status.

SUMMARY

Green nail syndrome, toe web infection, hot tub folliculitis, hot hand-foot infection and external otitis are the most common infections originating from the skin per se. Local treatments are the cornerstone and prognosis is favorable in immunocompetent hosts. Ecthyma gangrenosum and P. aeruginosa subcutaneous nodules are usually associated with bloodstream infections and occur primarily in immunocompromised hosts. Necrotizing skin and soft tissue infections occur in diabetic, alcoholic and immunocompromised patients; management requires a multidisciplinary team with surgical approach. Burn wound infections may also be challenging, requiring a specialized team. In all the four latter types of P. aeruginosa skin infections portending significant morbidity and mortality, systemic antibiotics are an integral part of the treatment.

Necrotizing skin and soft-tissue infections in the intensive care unit

BACKGROUND

Necrotizing skin and soft-tissue infections (NSTI) are rare but potentially life-threatening and disabling infections that often require intensive care unit admission.

OBJECTIVES

To review all aspects of care for a critically ill individual with NSTI.

SOURCES

Literature search using Medline and Cochrane library, multidisciplinary panel of experts.

CONTENT

The initial presentation of a patient with NSTI can be misleading, as features of severe systemic toxicity can obscure sometimes less impressive skin findings. The infection can spread rapidly, and delayed surgery worsens prognosis, hence there is a limited role for additional imaging in the critically ill patient. Also, the utility of clinical scores is contested. Prompt surgery with aggressive debridement of necrotic tissue is required for source control and allows for microbiological sampling. Also, prompt administration of broad-spectrum antimicrobial therapy is warranted, with the addition of clindamycin for its effect on toxin production, both in empirical therapy, and in targeted therapy for monomicrobial group A streptococcal and clostridial NSTI. The role of immunoglobulins and hyperbaric oxygen therapy remains controversial.

IMPLICATIONS

Close collaboration between intensive care, surgery, microbiology and infectious diseases, and centralization of care is fundamental in the approach to the severely ill patient with NSTI. As many aspects of management of these rare infections are supported by low-quality data only, multicentre trials are urgently needed.

Necrotizing fasciitis: case series and review of the literature on clinical and medico-legal diagnostic challenges

Necrotizing fasciitis (NF) is a life-threatening infection of soft tissues spreading along the fasciae to the surrounding musculature, subcutaneous fat and overlying skin areas that can rapidly lead to septic shock and death. Due to the pandemic increase of medical malpractice lawsuits, above all in Western countries, the forensic pathologist is frequently asked to investigate post-mortem cases of NF in order to determine the cause of death and to identify any related negligence and/or medical error. Herein, we review the medical literature dealing with cases of NF in a post-mortem setting, present a case series of seven NF fatalities and discuss the main ante-mortem and post-mortem diagnostic challenges of both clinical and forensic interests. In particular, we address the following issues: (1) origin of soft tissue infections, (2) micro-organisms involved, (3) time of progression of the infection to NF, (4) clinical and histological staging of NF and (5) pros and cons of clinical and laboratory scores, specific forensic issues related to the reconstruction of the ideal medical conduct and the evaluation of the causal value/link of any eventual medical error.

Necrotising fasciitis caused by P aeruginosa in a male patient with chronic lymphocytic leukaemia

A 53-year-old man with chronic lymphocytic leukaemia and multiple comorbidities presented with a 2-day history of increasing pain and swelling in his left leg following a minor trauma, associated with signs of systemic sepsis and worsening multiorgan failure. The clinical picture was consistent with necrotising fasciitis and he was taken to the theatre for an above-knee amputation. Blood and tissue cultures grew Pseudomonas aeruginosa only, which is very rare as a monomicrobial infection, with relatively few cases being reported in the literature. The combination of aggressive timely surgical intervention, broad-spectrum antibiotics and treatment on the intensive care unit yielded a successful outcome from this acute episode.