Infections with the Unusual Human Pathogens Agrobacterium Species and Ochrobactrum anthropi

Abstract

Agrobacterium species and Ochrobactrum anthropi are generally considered innocuous in clinical settings, yet during the last decade a number of sporadic cases of human infection due to these organisms have been reported. We studied nine cases of infection (septicemia and peritonitis) caused by Agrobacterium-like microorganisms in eight patients. All patients were immunocompromised and had permanent central venous or peritoneal dialysis catheters in place. Seven patients were women, and eight infections were community acquired. Six isolates were identified as Agrobacterium species and three as O. anthropi. These two groups of strains differed in the production of beta-galactosidase and of acid from lactose, erythritol, salicin, and cellobiose. All strains were strictly aerobic, peritrichous, gram-negative bacilli that produced oxidase, urease, and acid from glucose, fructose, arabinose, xylose, mannitol, inositol, and ethanol. The in vitro adherence of isotope-labeled bacteria to silicone tubes was similar to that of staphylococci. We conclude that Agrobacterium species and O. anthropi can be pathogenic in immunocompromised patients with permanent catheters.

Agrobacterium yellow group: bacteremia and possible septic arthritis following peripheral blood stem cell transplantation

“…In one report, 16 patients with catheter-related infection had negative tip culture, but were found to have positive hub culture. 17 The propensity to colonize foreign devices may be due to the ability of Agrobacterium to adhere to silicone tubes, similar to Staphylococcus aureus and Staphylococcus epidermidis as shown by Alnor et al 3 Central venous catheter infection due to Agrobacterium spp. has mainly been described with Agrobacterium radiobacter.…”

“…This has been described in a previous report when bacteria may escape detection by conventional culturing of the catheter. 3 The sensitivity of catheter tip cultures is reported to range from 78 to 97%. [16][17][18] In our case, a false-negative result may be due to failure to use techniques which would allow detection of organisms present in the internal lumen of catheter.…”

“…1,3 The infection could be controlled only after removing the catheter in 57 to 83% of the cases. [1][2][3]19,20 Central venous catheter infection with Agrobacterium yellow group, to our knowledge, has never been described. The only report of human infection with this pathogen to date was peritonitis in four patients receiving continuous ambulatory peritoneal dialysis.…”

“…Some authors have described Agrobacteria as emerging opportunistic pathogens, primarily Agrobacterium radiobacter. [1][2][3] Reported infection due to Agrobacterium yellow group is rare, with only one report in the literature describing four cases. 4 Infection with unusual organisms may present with unique clinical problems.…”

Specific detection and differentiation of Ochrobactrum anthropi, Ochrobactrum intermedium and Brucella spp. by a multi-primer PCR that targets the recA gene

“…Whereas brucellae are well recognized as important pathogens that cause brucellosis in man and many animal species, Ochrobactrum anthropi and O. intermedium have only recently emerged as human pathogens (Alnor et al, 1994;Möller et al, 1999;Mahmood et al, 2000;Apisarnthanarak et al, 2005;Vaidya et al, 2006;Kämpfer et al, 2007). In the past, O. anthropi and O. intermedium have been regarded as opportunistic human pathogens of low virulence, infecting only immunocompromised patients with underlying diseases.…”