Antibiotic Resistance in Aeromonas hydrophila and Vibrio alginolyticus Isolated from a Wound Infection: A Case Report

Abstract

Aeromonas hydrophila is a motile, nonsporulating, fermentative, facultative, anaerobic, gram-negative bacillus commonly found in fresh water, tap water, soil, and swimming pools. 1,2 Human infections caused by Aeromonas spp. are frequently associated with trauma in the aquatic environment, 3-7 immunosuppression, 7 and chronic disease. 8 ␤-Lactam resistance in Aeromonas spp. has been reported. 9 In clinical Aeromonas isolates, genetic properties of the ␤-lactamase genes have been characterized. 9 -12 Previous reports 9,13 demonstrated that Aeromonas spp. can produce multiple ␤-lactamases, including a carbapenem-hydrolyzing metallo-␤-lactamase, which is an important problem for antibiotic treatment.Vibrio alginolyticus is a facultatively anaerobic, gramnegative bacillus with a single polar flagellum for mobility. 14 V. alginolyticus, a halophilic bacterium, is common in coastal waters and sediments all over the world. 15 Human infections caused by V. alginolyticus include ear, soft tissue, and wound infections. 14,16,17 Recent reports 18 showed that 40% of V. alginolyticus isolated from the environment produce ␤-lactamases conferring resistance to ampicillin. Antibiotic resistance in V. alginolyticus is a significant problem for wound infections related to the aquatic environment.We describe a wound infection caused by both A. hydrophila and V. alginolyticus related to an aquatic environment. Genetic analysis suggests that microbiologic examination is critical, because these aquatic environment-related isolates had a variety of determinants of antibiotic resistance. CASE REPORTA 37-year-old man had fallen out of a boat at Hamana Lake in Japan, twining his left fingers in a rope, and the left second and third digits were amputated in 2001. The amputated digits were exposed to the lake water for several minutes to an hour. He was admitted to a Hamamatsu city hospital. At admission, laboratory examination revealed a C-reactive protein concentration of 1 mg/L (normal, 0 -1 mg/L), a white blood cell count (WBC) of 12.9 ϫ 10 9 cells/L (normal, 3.5-8.9 ϫ 10 9 cells/L), and a platelet count of 281 ϫ 10 9 /L (normal, 147-332 ϫ 10 9 /L). After surgical treatment with replantation and stump plasty, intravenous cefazolin 2 g administered twice daily was started. However, the replantated fingers had necrosis and wound infection. On hospital day 12, the fingers were removed. Both A. hydrophila SHH-029 and V. alginolyticus SHH-031 were isolated from wound fluid collected on day 12. Then, antibiotic therapy was changed to intravenous imipenem 0.5 g administered twice daily. Laboratory examination revealed a C-reactive protein concentration of 57 mg/L, a white blood cell count of 12.1 ϫ 10 9 cells/L, and a platelet count of 456 ϫ 10 9 /L. Minimum inhibitory concentrations (MICs) were determined by the agar dilution method as described by the National Committee for Clinical Laboratory Standards. 19 Susceptibility testing was performed on Mueller-Hinton agar (Nippon Becton Dickinson, Tokyo, Japan). The results of susceptibility testi...

Diabetic Foot Infections: Microbiology Made Modern?

“…With PCR methods, it is possible to detect most species of pathogens in a wound in a matter of hours rather than days. PCR has already shown promise in various clinical situations, including identifying antibiotic-resistant gram-negative organisms (20), bacteria that elaborate neurotoxins (21) or other virulence factors (22), and slow-growing organisms like mycobacteria (23). Additionally, previous antibiotic therapy would be much less likely to cause false-negative results than with a standard culture.…”

Aeromonas hydrophila Infection Causing Delayed Vascular Thrombosis in a Nearly Amputated Finger

“…Several studies have documented the antibiotic resistance profile of Aeromonas hydrophila. 15,16 Therefore, recommended antibiotics to treat this organism include intravenous fluoroquinolones or a third-or fourth-generation cephalosporin. 17 This organism is known to cause severe wound infections and to compromise revascularized limbs when these injuries are sustained in an aquatic environment.…”

Study of prevalence and antibiotic resistance in Aeromonas species isolated from minced meat and chicken samples in Iran

“…Interestingly, A. hydrophila is the predominant strain in clinical samples, which can prove the role it can play in pathogenesis. Therefore, it deserves even more attention (Garibay et al, 2006;Horii et al, 2005;Pokhrel and Thapa, 2004). In this study, the predominant species in minced meat was A. hydrophila (59%) followed by A. caviae (20.6%), A. sobria (17%), A. jandaei (3.4%).…”

“…In a study, motile Aeromonas species were present in all samples including retail lamb meat and offal; so it was concluded that meat products were potentially significant sources of virulent Aeromonas species and might play an important role in the etiology of Aeromonas gastroenteritis (Majeed et al, 1989). Aeromonads had been regarded as controversial pathogens; however, recent investigations have indicated some strains are entropathogenic (Garibay et al, 2006;Horii et al, 2005;Pokhrel and Thapa, 2004;Sinha et al, 2004;Soltan Dallal and Moezardalan, 2004;Vila et al, 2003). Of the various virulence factors described to explain the pathogenicity of Aeromonas species, beta hemolytic activity seems to be related to enterotoxigenicity (Chopra et al, 1991;Wong et al, 1998).…”