Postirradiation Klebsiella pneumoniae-associated necrotizing fasciitis in the western hemisphere: a rare but life-threatening clinical entity

Necrotizing fasciitis in patients with head and neck cancer

Necrotizing fasciitis is a severe polybacterial infection characterized by necrosis of the fascia and adjacent soft tissues with rapid expansion of the infection along the fascial planes. It is a rare and potentially fatal entity in the head and neck region. We present 2 patients with head and neck cancers who developed necrotizing fasciitis during the postoperative period.

Necrotizing fasciitis caused by hypermucoviscous Klebsiella pneumoniae in a Filipino female in North America

Necrotizing fasciitis caused by Klebsiella pneumoniae has been described in Southeast Asia, but has only recently begun to emerge in North America. The hypermucoviscous strain of K. pneumoniae is a particularly virulent strain known to cause devastatingly invasive infections, including necrotizing fasciitis. Here we present the first known case of necrotizing fasciitis caused by hypermucoviscous K. pneumoniae in North America.

Monomicrobial necrotizing fasciitis in a single center: the emergence of Gram-negative bacteria as a common pathogen

BACKGROUND

Necrotizing fasciitis (NF) is a life-threatening soft tissue infection. It is usually caused by Streptococcus pyogenes and other Gram-positive bacteria. Several reports, however, emphasize the importance of Gram-negative rods in this infection.

METHODS

We retrospectively studied all cases of monomicrobial necrotizing fasciitis hospitalized in our center during the years 2002-2012. We compared clinical characteristics and outcomes of patients with Gram-negative versus Gram-positive infection.

RESULTS

Forty-five cases were reviewed, 19 caused by Gram-negative organisms, 10 of them Escherichia coli, and 26 caused by Gram-positive organisms, 10 of them S. pyogenes. Compared to Gram-positive infections, patients with Gram-negative infections were more likely to have a baseline malignancy (9/19, 47.4%) or to have undergone recent surgery (4/19, 42.3%). The 30-day mortality was higher among Gram-negative infected patients (8/19, 42.1% vs. 8/26, 30.8%). Creatine phosphokinase (CPK) was elevated in a minority of patients with Gram-negative necrotizing fasciitis, and its absolute value was lower than in Gram-positive necrotizing fasciitis.

CONCLUSIONS

In our center, 42% of monomicrobial necrotizing fasciitis cases were found to be caused by Gram-negative organisms, mostly E. coli. These infections usually appeared in immunocompromised or postoperative patients, often presented with normal CPK levels, and were associated with high mortality rates.

Klebsiella pneumoniae necrotizing fasciitis of the leg in an elderly French woman

Klebsiella pneumoniae necrotizing fasciitis is a rare infection in regions outside of Asia. Here, we present a case of necrotizing fasciitis of the leg caused by K. pneumoniae in a 92-year-old French woman hospitalized in a geriatric rehabilitation unit. The patient initially presented with dermohypodermitis of the leg that developed from a dirty wound following a fall. A few hours later, this painful injury extended to the entire lower limb, with purplish discoloration of the skin, bullae, and necrosis. Septic shock rapidly appeared and the patient died 9 hours after the onset of symptoms. The patient was Caucasian, with no history of travel to Asia or any underlying disease. Computed tomography revealed no infectious metastatic loci. Blood cultures showed growth of capsular serotype K2 K. pneumoniae strains with virulence factors RmpA, yersiniabactin and aerobactin. This rare and fatal case of necrotizing fasciitis caused by a virulent strain of K. pneumoniae occurred in a hospitalized elderly woman without risk factors. Clinicians and geriatricians in particular should be aware of this important albeit unusual differential diagnosis.

Recent trend of necrotizing fasciitis in Taiwan: focus on monomicrobial Klebsiella pneumoniae necrotizing fasciitis

BACKGROUND

Necrotizing fasciitis (NF) is a rapidly progressive, life-threatening soft-tissue infection that is traditionally caused by group A Streptococcus (GAS) or mixed aerobic/anaerobic bacteria. Monomicrobial Klebsiella pneumoniae NF (KP-NF) has been reported since 1996 but has not yet been systematically studied.

METHODS

We retrospectively studied consecutive NF cases treated at a university hospital in Taiwan during 1997-2010 and investigated the clinical characteristics and outcomes associated with monomicrobial KP-NF, using monomicrobial GAS-NF as a reference. We also analyzed the virulence gene profiles of the isolated K. pneumoniae strains.

RESULTS

Of 134 NF cases, 88 were monomicrobial, of which the most common pathogens were GAS (n = 16) and K. pneumoniae (n = 15). Monomicrobial KP-NF entailed a moderate risk of limb loss (20% vs 25%; P = 1.000) and high mortality (47% vs 19%; P = .135), and it was more likely to involve bacteremia (80% vs 31%; P = .011), concomitant distant abscesses (27% vs 0%; P = .043), and underlying immunocompromising conditions (100% vs 63%; P = .018), compared with GAS-NF. The isolated K. pneumoniae strains (n = 10) were of capsular polysaccharides genotype K1 (n = 4), K54/K20/K5 (n = 4), K2 (n = 1), and K16 (n = 1). All strains carried rmpA, iucABCDiutA, and iroA. Genotype K1 strains had a significantly higher risk of concomitant distant abscesses, compared with non-K1 strains (75% vs 0%; P = .033).

CONCLUSIONS

K. pneumoniae has become a common pathogen of monomicrobial NF in Taiwan. Physicians treating patients with monomicrobial KP-NF should be aware of the risk of concomitant distant abscesses, particularly in cases caused by genotype K1.

Necrotizing fasciitis following psoas muscle abscess caused by hypermucoviscous Klebsiella pneumoniae

A 59-year-old Japanese diabetic woman was admitted to a small private hospital with general malaise, fever, and a 1-month history of low back pain. A computed tomography scan of the abdomen revealed left abdominal necrotizing fasciitis with suspected left psoas muscle abscess. She was transferred to Gunma University Hospital, received antibiotic therapy, and underwent debridement of the infected subcutaneous tissue, fascia, and necrotic left psoas muscle. She was transferred to the intensive care unit to receive mechanical ventilation and inotropic support. Blood culture showed growth of Klebsiella pneumoniae, from which hypermucoviscosity was detected by the string test. She was extubated on day 5 of hospitalization and transferred to a general ward on day 14. Free skin grafting was performed on day 76, and she was discharged on day 134 without any complications.