Ochrobactrum anthropi peritonitis in a CAPD patient

The Genus Ochrobactrum as Major Opportunistic Pathogens

Ochrobactrum species are non-enteric, Gram-negative organisms that are closely related to the genus Brucella. Since the designation of the genus in 1988, several distinct species have now been characterised and implicated as opportunistic pathogens in multiple outbreaks. Here, we examine the genus, its members, diagnostic tools used for identification, data from recent Ochrobactrum whole genome sequencing and the pathogenicity associated with reported Ochrobactrum infections. This review identified 128 instances of Ochrobactrum spp. infections that have been discussed in the literature. These findings indicate that infection review programs should consider investigation of possible Ochrobactrum spp. outbreaks if these bacteria are clinically isolated in more than one patient and that Ochrobactrum spp. are more important pathogens than previously thought.

Ochrobactrum anthropi: an unusual pathogen: are we missing them?

With increasing incidence of immunocompromised patients, many unusual organisms are emerging as pathogens in these patients. Ochrobactrum anthropi is an emerging opportunistic pathogen in immunocompromised patients. Here, we report two cases of neonates who presented with septicemia due to O. anthropi. Both were preterm and low birth weight babies admitted in the Neonatal Intensive Care Unit of our Hospital. One baby manifested with respiratory distress and eventually died. The second baby responded well to treatment and was discharged. The clinical presentation of infections along with microbiological characteristics and clinical significance of the organism are described.

An opportunistic pathogen in a peritoneal dialysis patient: Ochrobactrum anthropi

The authors report a case of chronic peritoneal dialysis-related peritonitis from Ochrobactrum anthropi. O. anthropi is an emerging pathogen in immunocompromised patients. O. anthropi-related peritonitis in peritoneal dialysis patients has rarely been reported. To the authors' knowledge, no pediatric case of O. anthropi peritonitis has been reported to date in the literature.

Recurrent Ochrobactrum anthropi and Shewanella putrefaciens bloodstream infection complicating hemodialysis

Bloodstream infections (BSIs) are common in hemodialysis, especially when the access is a catheter. These infections are more commonly gram-positive bacteria or gram-negative bacilli and on some occasions, fungi. Ochrobactrum anthropi and Shewanella putrefaciens are ubiquitous hydrophilic gram-negative bacilli. There have been three cases of O. anthropi BSI reported in hemodialysis patients (one from the United States and two from Vienna) and two cases of S. putrefaciens BSI in hemodialysis patients (one from the United States and the other from Japan). There have been few more cases reported of infections with these bacteria in peritoneal dialysis, especially outside the United States. We present a novel case of a patient with both recurrent O. anthropi and S. putrefaciens BSI complicating hemodialysis. There have been no reports in the literature of such a case. We also discuss the microbiology, clinical features, and the challenging aspects of treatment of such infections.

Peritonitis in type 2 diabetes mellitus due to Ochrobactrum anthropi complicating automated peritoneal dialysis

Epidemiology data predict that by the year 2025, diabetes will affect about 380 million people worldwide with a significant increase in patients with chronic renal disease progressing to hemodialysis. Diabetes-related peripheral vascular disease is a major risk factor for vascular access failure in patients on extracorporeal hemodialysis. Although peritoneal dialysis is a valid option for diabetics, peritonitis is still a main complication for these patients. We report the case of a 71-year-old type 2 diabetes patient treated by subcutaneous insulin, undergoing automated peritoneal dialysis (APD) who developed peritonitis and bloodstream infection by Ochrobactrum anthropi (O. anthropi). The patient was initially shifted to continuous ambulatory peritoneal dialysis (CAPD) and treated with intraperitoneal cefotaxime and gentamicin. According to antibiogram, cefotaxime was discontinued but lasting gentamicin. Within 48 h from admission, clear peritoneal effluent was observed with reduction in white blood cells count from 580/mm³ 77.9% neutrophils to less than 10/mm³. Prompt regression of infection without catheter removal and no relapse after over 7-month follow-up allowed supposing that O. anthropi did not colonized peritoneal catheter. O. anthropi is an emerging cause of nosocomial infection in immunocompromised patients. Cases of such infection in patients undergoing CAPD and hemodialysis have been already described. However, this is the first reported case of O. anthropi in a patient undergoing APD.

Identification and antimicrobial susceptibilities of Ochrobactrum spp

Ochrobactrum (O.) anthropi is an opportunistic emerging pathogen closely related to the genus Brucella. Identification and differentiation from brucellae and other Ochrobactrum spp. using routine biochemical test systems is not reliable due to the high phenotypic similarity. In this study, antibiotic susceptibilities of 103 Ochrobactrum isolates were determined using Etest for 19 clinically relevant antimicrobial agents. Ochrobactrum strains were highly resistant to beta-lactam antibiotics, susceptible to ciprofloxacin, and 97.1% were susceptible to trimethoprim/sulfamethoxazole. It was also demonstrated that biochemical reaction profiles of the API and BD Phoenix 100 systems for identifying Ochrobactrum isolates can only be used on the genus level. Our in vitro data suggest that combinations of antimicrobial agents including ciprofloxacin and/or trimethoprim/sulfamethoxazole may be useful for empirical treatment of Ochrobactrum infections.

Spontaneous bacterial peritonitis due to Ochrobactrum anthropi: a case report

We report a case of spontaneous bacterial peritonitis from Ochrobactrum anthropi. O. anthropi is recognized as an emerging pathogen in immunocompromised patients. In contrast to most previously described cases, the patient reported here had no indwelling catheter. To our knowledge, no case of O. anthropi spontaneous bacterial peritonitis has been reported in the medical literature until now.

Septic shock caused by Ochrobactrum anthropi in an otherwise healthy host

Reported is a case of life-threatening septic shock that occurred in an otherwise healthy host after administration of a peripheral venous infusion of a solution contaminated with Ochrobactrum anthropi, an unusual human pathogen. The rapid onset of shock may have been due to a large inoculum caused by nonsterile practices at the time of reconstitution.

[Species identification and molecular epidemiology of bacteria belonging to Ochrobactrum genus]

Two species of medical interest belong to the genus Ochrobactrum, Ochrobactrum anthropi and Ochrobactrum intermedium. They are members of the microbiota of soil and an increasing number of works report the isolation of O. anthropi from clinical specimen, especially from immunocompromised patients and nosocomial infection. Involving of each species in human infection is poorly estimated due to unclear differential phenotypic characters. We performed 16S rDNA sequencing for identification of 20 clinical isolates of Ochrobactrum sp. to the species level. Then, we studied the phenotype of each isolate especially, morphology, culture onto different media and at different temperatures, biochemical characters and antibiotics resistance pattern. Colony morphology after growth onto Trypticase-Soy and McConkey agar, culture at 45 degrees C onto Trypticase-Soja agar, presence of urease, and netilmycin, tobramycin and colistin resistance allowed identification of species. Ribotyping using HindIII and EcoRI gave a supplementary criterion for species determination but did not allow typing at the infra-species level. In contrast, Pulsed-Field Gel Electrophoresis showed high degree of polymorphism between strains and proved the clonality of certain isolates. Thus, this method could be a useful tool for molecular epidemiology of Ochrobactrum infections.

Ochrobactrum anthropi bloodstream infection complicating hemodialysis

We report two cases of bacteremia with Ochrobactrum anthropi in patients on hemodialysis. Bacteremia became clinically manifest by recurrent febrile episodes during and after dialysis. In one patient, bacteremia persisted after ciprofloxacin therapy and was cleared only by removal of the dialysis catheter and a 3-week course of gentamicin. The second patient remained intermittently bacteremic for more than 3 months, although the dialysis catheter had been replaced. A MEDLINE search revealed only one previous report of O anthropi bloodstream infection in a patient on hemodialysis, but the pathogen is recognized increasingly as a causative agent of human disease, most importantly in debilitated patients. In contrast to most previously described cases, the two patients reported here had no malignancies and were not on immunosuppressive therapy. Treatment of O anthropi infection is challenging because of widespread and unpredictable resistance to antimicrobial agents and discrepancies between in vitro susceptibility and in vivo efficacy.

Molecular characterization of chromosomal class C beta-lactamase and its regulatory gene in Ochrobactrum anthropi

Ochrobactrum anthropi, formerly known as CDC group Vd, is an oxidase-producing, gram-negative, obligately aerobic, non-lactose-fermenting bacillus of low virulence that occasionally causes human infections. It is highly resistant to all beta-lactams except imipenem. A clinical isolate, SLO74, and six reference strains were tested. MICs of penicillins, aztreonam, and most cephalosporins tested, including cefotaxime and ceftazidime, were >128 microg/ml and of cefepime were 64 to >128 microg/ml. Clavulanic acid was ineffective and tazobactam had a weak effect in association with piperacillin. Two genes, ampR and ampC, were cloned by inserting restriction fragments of genomic DNA from the clinical strain O. anthropi SLO74 into pBK-CMV to give the recombinant plasmid pBK-OA1. The pattern of resistance to beta-lactams of this clone was similar to that of the parental strain, except for its resistance to cefepime (MIC, 0.5 ,micro/ml). The deduced amino acid sequence of the AmpC beta-lactamase (pI, 8.9) was only 41 to 52% identical to the sequence of other chromosomally encoded and plasmid-encoded class C beta-lactamases. The kinetic properties of this beta-lactamase were typical for this class of beta-lactamases. Upstream from the ampC gene, the ampR gene encodes a protein with a sequence that is 46 to 62% identical to those of other AmpR proteins and with an amino-terminal DNA-binding domain typical of transcriptional activators of the Lys-R family. The deduced amino acid sequences of the ampC genes of the six reference strains were 96 to 99% identical to the sequence of the clinical strain. The beta-lactamase characterized from strain SLO74 was named OCH-1 (gene, bla(OCH-I)).