Buttock abscess due to Hafnia alvei

Catheter-associated Hafnia alvei-induced Urosepsis

Hafnia alvei, belonging to the Enterobacteriaceae family, is a gram-negative, facultative anaerobe. The organism predominantly colonizes the gastrointestinal tract and, less often, the tissues, urine, and catheters. A 75-year-old male presented with a dry cough, fatigue, decreased appetite, intermittent disorientation, and difficulty ambulating. He had a history of self-catheterization due to urinary retention. He was scheduled to undergo transcatheter aortic valve replacement for enterococcal endocarditis. Physical examination was not significant for any changes. Urine analysis revealed positive leukocyte esterase, the presence of red and white blood cells, urine bacteria, and hyaline casts. The patient was started on empiric intravenous ceftriaxone. Urine culture grew Hafnia alvei and he was switched over to cefepime due to greater susceptibility. On day four, he started deteriorating clinically and was treated with four pressors but remained hypotensive and eventually became anuric. The patient developed septic shock with multiple organ dysfunction syndromes. Despite all measures, his clinical condition failed to improve, and he was continued with comfort measures only. The literature on Hafnia alvei-induced urosepsis is poor and fragmentary. Our patient showed resistance to most beta-lactam antibiotics, including cefuroxime, ceftriaxone, and ceftazidime, along with intermediate susceptibility to piperacillin/tazobactam and was managed with intravenous cefepime based on the sensitivity report. Inducible Bush group 1 beta-lactamase produced by Hafnia alvei is postulated to be responsible for antibiotic resistance. Physicians should remain vigilant of Hafnia alvei-induced urosepsis in patients with long-term catheterization initiating appropriate treatment.

Hafnia alvei: A new pathogen in open fractures

Background

Deep infection following open both bone forearm fractures is a rare complication. Prophylactic antibiotic regimens are targeted at the most common pathogens, which include primarily Staph aureus followed by gram-negative bacteria. Hafnia alvei is an unusual pathogen that is rarely pathogenic in humans and has never been reported as a cause of infection following open fracture.

Methods

We present a 12-year-old male with an open forearm fracture who developed a late deep infection. Cultures grew only Hafnia alvei. The patient was treated with debridement, placement of antibiotic beads, and ciprofloxacin.

Results

At 6 months following the initial debridement, the patient had no clinical evidence of infection and regained full function of the affected forearm without any residual deficits.

Conclusions

This is the first report of deep infection following an open forearm fracture owing to Hafnia alvei, a pathogen rarely responsible for human infection.

The genus Hafnia: from soup to nuts

The genus Hafnia, a member of the family Enterobacteriaceae, consists of gram-negative bacteria that are occasionally implicated in both intestinal and extraintestinal infections in humans. Despite the fact that the genus currently contains only a single species (H. alvei), more extensive phylogenetic depth (two or more species) is apparent based upon DNA relatedness and 16S rRNA gene sequencing studies. Hafnia causes a variety of systemic infections, including septicemia and pneumonia; however, its role as a gastrointestinal pathogen is controversial. Many of the data supporting a role for hafniae as enteric pathogens were incorrectly attributed to this genus rather than to the actual pathogen, Escherichia albertii. There are numerous gaps in our understanding of this genus, including ecologic habitats and population genetics, disease-producing role in animals, phenetic and genetic methods useful in distinguishing genomospecies within the H. alvei complex, and bona fide pathogenicity factors.

Abdominal abscess and Hafnia alvei septicemia occurring during the aplastic phase after autologous stem-cell transplantation in a patient with diffuse large B-cell lymphoma

Hafnia alvei is a motile gram-negative bacterium that is rarely isolated from human specimens, but that sometimes can be found as part of the gastrointestinal flora. Here we report a rare case of Hafnia alvei septicemia with an abdominal abscess in a 60-year-old woman with diffuse large B-cell lymphoma involving the spleen, liver, and then lymph nodes. She initially received a splenectomy, and, over a 2-year period, four courses of chemotherapy. After achieving complete remission status, she underwent autologous peripheral blood stem-cell transplantation (PBSCT). During the aplastic phase following transplantation, the patient developed fever, diarrhea, and abdominal pain, with blood cultures positive for Hafnia alvei and an abscess in the splenic recess. Considering the high surgical risk, the infection was treated, successfully, with antibiotics (imipenem/cilastatin), without surgery or computed tomography (CT)-guided percutaneous drainage. Infections due to Hafnia alvei are rare, and this is the first reported case of Hafnia alvei septicemia in an adult hematologic patient undergoing a stem-cell transplantation procedure.

Virulence factors and pathogenicity of Hafnia alvei for gilthead seabream, Sparus aurata L

Virulence factors (eae gene, haemolytic capacity, fimbriae, resistance to the bactericidal effect of serum, siderophore production) and pathogenicity for gilthead seabream, Sparus aurata L., were analysed for 23 Hafnia alvei strains. None of the strains used in LD50 studies were lethal for seabream at doses as high as >10(8) cfu mL(-1). In chronic challenge studies differences in severity of the inflammatory response were observed between strains. On the basis of correlation of the inflammatory response to different strains of H. alvei in seabream with those virulence factors studied, it was only possible to establish a positive correlation between pathogenicity and resistance to the bactericidal effect of fish serum. Gilthead seabream is thus a species with considerable resistance to experimental infection with H. alvei. The bacterium does, however, have the capacity to remain viable in seabream for up to 3 months, without any clinical signs. Hafnia alvei is a well-recognized human and animal pathogen. Thus, as the pathogen can coexist with aquaculture operations, cultured gilthead seabream could represent a risk to human health as a carrier in some circumstances.

Natural antimicrobial susceptibility patterns and biochemical identification of Escherichia albertii and Hafnia alvei strains

Bangladeshi diarrheagenic Hafnia alvei-like strains have been described recently as the new species Escherichia albertii (Int J Syst Evolut Microbiol. 2003;53:807-810). The natural susceptibility of 21 E. albertii and 76 H. alvei strains to 69 antimicrobial agents was examined, applying a microdilution procedure in IsoSensitest broth (for all the strains) and cation-adjusted Mueller-Hinton broth (for some strains). Examining the phenotypic features of both taxa with commercial identification systems and conventional tests, a database for an accurate biochemical separation of E. albertii from H. alvei was also established. Both taxa were naturally sensitive or sensitive and of intermediate susceptibility to aminoglycosides, acylureidopenicillins, ticarcillin, several cephalosporins, carbapenems, aztreonam, quinolones, folate pathway inhibitors, and nitrofurantoin. They were naturally resistant to tetracycline, penicillin G, oxacillin, all macrolides except for azithromycin, lincosamides, streptogramins, glycopeptides, rifampicin, and fusidic acid. Taxon-related differences in natural susceptibility affecting clinical assessment criteria were seen with doxycycline, minocycline, aminopenicillins, some cephalosporins, azithromycin, and fosfomycin. E. albertii was more susceptible than H. alvei to these agents and was naturally sensitive to all beta-lactams (except for penicillin G and oxacillin), azithromycin, and fosfomycin. H. alvei was naturally resistant or of intermediate susceptibility to all tetracyclines, amoxicillin, amoxicillin-clavulanate, ampicillin-sulbactam, narrow-spectrum cephalosporins, azithromycin, and fosfomycin. Motile malonate-negative Hafnia strains (indicating genospecies 2 of the H. alvei complex) were less susceptible to some cephalosporins than nonmotile, malonate-positive hafniae (indicating genospecies 1). Proline deaminase, hydroxyproline amidase, tripeptidase, chitinase, Voges-Proskauer reaction, and assimilation of histidine as well as acid production from glycerol, rhamnose, and xylose were suitable tests to separate strains of E. albertii from those of the H. alvei complex. Although out of the scope of this study, it should be noted that several strains of E. albertii showed acquired resistances to some penicillins and antifolates.

Sepsis nosocomial por Hafnia alvei en una unidad de cuidados intensivos neonatales

Hafnia alvei is a member of the Enterobacteriaceae family, which is rarely associated with infection in pediatric patients and exceptionally in the neonatal period. Infections caused by this organism are usually opportunistic. H. alvei bacteremias are mostly associated with abdominal disease or immunosuppression. We report four cases of nosocomial sepsis in preterm infants with positive blood cultures to H. alvei that were treated in our institution within a short period of time.

Identification of Hafnia alvei with the MicroScan WalkAway system

Hafnia alvei is a gram-negative facultatively anaerobic bacillus that belongs to the family Enterobacteriaceae. This organism is a causative agent of intestinal disorders and is found in different environments. H. alvei has received increased clinical attention as a cause of different infections in humans. This study was performed to compare the MicroScan WalkAway automated identification system in conjunction with the new MicroScan Combo Negative type 1S panels with conventional biochemical methods for identification of 21 H. alvei strains. The MicroScan WalkAway system was found capable of correctly identifying 20 of the 21 strains tested.