Rhizobium radiobacter wound infection in a patient with diabetes--fact, factitious or just plain unlucky?

Fournier gangrene due to Rhizobium Radiobacter

Fournier's gangrene (FG) is a life-threatening, rapidly progressing acute necrotizing fasciitis of perianal, genitourinary and perineal areas. The most common isolated pathogens are E.coli, Streptococcus and Enterococcus in tissue and abscess cultures. However we present the first Rhizobium radiobacter FG in this case. A 47-year-old man presented with black necrotizing area with malodorous pus drainage in the bottom of the right hemiscrotum. Intravenous imipenem and Clindamycin were started prophylactically; all necrotizing tissues were debrided and right hemiscrotectomy was performed. Rhizobium radiobacter was isolated from tissue and abscess cultures. After successful treatment patient was discharged posteroperative 18th day. The combination therapy of early and totally surgical debridement of necrotic tissues and appropriate antibiotic use are adequate to control Rhizobium radiobacter infection in FG.

Infections Caused by Antimicrobial Drug-Resistant Saprophytic Gram-Negative Bacteria in the Environment

Background

Drug-resistance genes found in human bacterial pathogens are increasingly recognized in saprophytic Gram-negative bacteria (GNB) from environmental sources. The clinical implication of such environmental GNBs is unknown.

Objectives

We conducted a systematic review to determine how often such saprophytic GNBs cause human infections.

Methods

We queried PubMed for articles published in English, Spanish, and French between January 2006 and July 2014 for 20 common environmental saprophytic GNB species, using search terms “infections,” “human infections,” “hospital infection.” We analyzed 251 of 1,275 non-duplicate publications that satisfied our selection criteria. Saprophytes implicated in blood stream infection (BSI), urinary tract infection (UTI), skin and soft tissue infection (SSTI), post-surgical infection (PSI), osteomyelitis (Osteo), and pneumonia (PNA) were quantitatively assessed.

Results

Thirteen of the 20 queried GNB saprophytic species were implicated in 674 distinct infection episodes from 45 countries. The most common species included Enterobacter aerogenes, Pantoea agglomerans, and Pseudomonas putida. Of these infections, 443 (66%) had BSI, 48 (7%) had SSTI, 36 (5%) had UTI, 28 (4%) had PSI, 21 (3%) had PNA, 16 (3%) had Osteo, and 82 (12%) had other infections. Nearly all infections occurred in subjects with comorbidities. Resistant strains harbored extended-spectrum beta-lactamase (ESBL), carbapenemase, and metallo-β-lactamase genes recognized in human pathogens.

Conclusion

These observations show that saprophytic GNB organisms that harbor recognized drug-resistance genes cause a wide spectrum of infections, especially as opportunistic pathogens. Such GNB saprophytes may become increasingly more common in healthcare settings, as has already been observed with other environmental GNBs such as Acinetobacter baumannii and Pseudomonas aeruginosa.