Ochrobactrum Anthropi Bacteremia Associated With a Catheter in an Immunocompromised Child and Review of the Pediatric Literature

Saavedra, Jesús; Garrido, Carmen; Folgueira, Lola; Torres, María José; Ramos, José Tomás

doi:10.1097/00006454-199907000-00023

Cited by 26 publications

(18 citation statements)

References 14 publications

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“…are increasingly recognized as emerging pathogens. Although most Ochrobactrum infections have been observed in immunocompromised patients (Apisarnthanarak et al, 2005;Chertow, 2000;Christenson et al, 1997;Cieslak et al, 1996;Saavedra et al, 1999) or associated with contaminated allografts (CDC, 1996;Chang et al, 1996), several reports indicate that Ochrobactrum can also cause infections in otherwise healthy humans (Berman et al, 1997;Braun et al, 1996;Galanakis et al, 2002). Patients infected with Ochrobactrum spp.…”

Section: Introductionmentioning

confidence: 99%

Identification and antimicrobial susceptibilities of Ochrobactrum spp.

Thoma

Straube

Scholz

et al. 2009

International Journal of Medical Microbiology

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Section: Introductionmentioning

confidence: 99%

Identification and antimicrobial susceptibilities of Ochrobactrum spp.

Thoma

Straube

Scholz

et al. 2009

International Journal of Medical Microbiology

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“…It is generally susceptible to carbapenems and aminoglycosides (19), trimethoprim-sulfamethoxazole (4), ciprofloxacin, and tetracyclines. The most effective antimicrobial agents for treating human infections are imipenem, trimethoprim-sulfamethoxazole, and ciprofloxacin (7), sometimes in conjunction with catheter removal (28). As this bacterium displays extensive resistance to ␤-lactams, we screened for and cloned a ␤-lactamase gene.…”

mentioning

confidence: 99%

Molecular Characterization of Chromosomal Class C β-Lactamase and Its Regulatory Gene in Ochrobactrum anthropi

Nadjar

Labia

Cerceau

et al. 2001

Antimicrob Agents Chemother

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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 ␤-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 g/ml and of cefepime were 64 to >128 g/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 ␤-lactams of this clone was similar to that of the parental strain, except for its resistance to cefepime (MIC, 0.5 g/ml). The deduced amino acid sequence of the AmpC ␤-lactamase (pI, 8.9) was only 41 to 52% identical to the sequence of other chromosomally encoded and plasmid-encoded class C ␤-lactamases. The kinetic properties of this ␤-lactamase were typical for this class of ␤-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 ␤-lactamase characterized from strain SLO74 was named OCH-1 (gene, bla OCH-I ).The species of the genus Ochrobactrum form two groups: Ochrobactrum anthropi and O. intermedium (25). O. anthropi, formerly classified as CDC group Vd, is a nonfastidious, gramnegative bacillus that is strictly aerobic, oxidase positive, and motile (with peritrichous flagella), does not ferment lactose, and has strong urease activity (8,16). O. anthropi is widespread and is distributed in water and hospital environments. In some cases, it has been isolated from water-based environments in hospitals (antiseptic solutions, dialysis fluids) (12). It has often been found on human clinical material: it often adheres to catheters, but pacemakers, intraocular lenses, and silicon tubing may also become infected (10, 18). Although only weakly virulent, O. anthropi causes hospital-acquired infections, often in immunocompromised hosts (7,11, 14,27). O. anthropi is usually resistant to ␤-lactams, such as broad-spectrum penicillins and oxyimino cephalosporins, except for cefepime in some cases and aztreonam (3). It is generally susceptible to carbapenems and aminoglycosides (19), trimethoprim-sulfamethoxazole (4), ciprofloxacin, and tetracyclines. The most effective antimicrobial agents for treating human infections are imipenem, trimethoprim-sulfamethoxazole, and ciprofloxacin (7), sometimes in conjunction with catheter removal (28). As this bacterium displays extensive resistance to ␤-lactams...

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“…For this purpose, the members of the genus Ochrobactrum are particularly suitable. These bacteria are very close to Brucella by DNA, rRNA, and protein analysis (12,23,59,62,65), but they are primarily soil dwellers known to be pathogenic only in critically ill or immunocompromised patients or in patients with indwelling catheters (10,11,25,26,34,52,66). Although in such situations Ochrobactrum can cause meningitis, osteomyelitis, bacteremia, and septicemia, these bacteria are unable to establish chronic infections by themselves and are cleared from normal hosts after catheter removal (16).…”

mentioning

confidence: 99%

Brucella abortusand Its Closest Phylogenetic Relative,Ochrobactrumspp., Differ in Outer Membrane Permeability and Cationic Peptide Resistance

et al. 2000

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The outer membrane (OM) of the intracellular parasite Brucella abortus is permeable to hydrophobic probes and resistant to destabilization by polycationic peptides and EDTA. The significance of these unusual properties was investigated in a comparative study with the opportunistic pathogens of the genus Ochrobactrum, the closest known Brucella relative. Ochrobactrum spp. OMs were impermeable to hydrophobic probes and sensitive to polymyxin B but resistant to EDTA. These properties were traced to lipopolysaccharide (LPS) because ( Brucella spp. are gram-negative bacteria of the ␣-2 subgroup of the domain Proteobacteria characteristically able to multiply intracellularly in a variety of cells (35). The pathogenicity of Brucella is not related to production of classical toxin, antiphagocytic capsules, proteinaceous adhesins, or plasmid-encoded virulence factors. On the other hand, the low endotoxicity of the lipopolysaccharide (LPS) (49), the resistance to a wide range of bactericidal cationic peptides (13,32), and the ability to prevent lysosome fusion and to locate in autophagosome-like compartments (46, 47) are characteristics of Brucella in all likelihood related to pathogenicity. Reduced endotoxicity and polycation resistance reflect properties of the LPS, and this molecule is also linked to additional peculiarities of the Brucella outer membrane (OM), such as its resistance to EDTA (13, 31, 38) and permeability to hydrophobic compounds (31). Because the OM plays a critical role in interaction of the bacteria with the environment, we have proposed (38,39,49) that the unusual set of properties of the Brucella OM is linked to its intracellular parasitism.A first approach to test this possibility is to obtain mutants altered in OM properties. We have recently produced polycation-sensitive mutants of B. abortus which, in support of our hypothesis, also show increased OM permeability to hydrophobic dyes, cannot penetrate into HeLa cells, and are avirulent in the mouse model (55). These mutants are disrupted in either of the two genes of a sensory/regulatory system (BvrR/BvrS) highly homologous to sensory/regulatory systems essential for virulence and endosymbiosis in Agrobacterium and Rhizobium, two plant-associated bacteria also belonging to the ␣-2 Proteobacteria (55). Moreover, we found that the divergence in BvrS is concentrated in the periplasmic sensory section (55); this shows that in the ␣-2 Proteobacteria, slight modifications of some basic systems reflect the adaptation to seemingly very different hosts and environments. Thus, a complementary approach to assess the relevance of the OM properties in the biology of Brucella is to perform comparative studies with phylogenetically related bacteria differing in pathogenicity. For this purpose, the members of the genus Ochrobactrum are particularly suitable. These bacteria are very close to Brucella by DNA, rRNA, and protein analysis (12,23,59,62,65), but they are primarily soil dwellers known to be pathogenic only in critically ill or immunocompromised patient...

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Ochrobactrum Anthropi Bacteremia Associated With a Catheter in an Immunocompromised Child and Review of the Pediatric Literature

Cited by 26 publications

References 14 publications

Identification and antimicrobial susceptibilities of Ochrobactrum spp.

Identification and antimicrobial susceptibilities of Ochrobactrum spp.

Molecular Characterization of Chromosomal Class C β-Lactamase and Its Regulatory Gene in Ochrobactrum anthropi

Brucella abortusand Its Closest Phylogenetic Relative,Ochrobactrumspp., Differ in Outer Membrane Permeability and Cationic Peptide Resistance

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