Septic sacroiliitis due to Proteus mirabilis

[Proteus mirabilis septic arthritis]

L'arthrite septique aigue est une pathologie peu fréquente mais grevée d'un pronostic lourd en termes de mortalité et morbidité. Nous rapportons un cas d'arthrite septique à Proteus mirabilis survenue de façon spontanée chez un patient de 61 ansprésentant un diabète compliqué,associée à des hémoculturespositives et des cultures positives du liquide articulaire. L'évolution était favorable grâce au diagnostic précoce et à l'institution d'une antibiothérapie adéquate. L'arthrite septique à Proteus Mirabilis est rare, ce qui nous a incité à revoir dans la littérature des séries d'arthrites à pyogènes incluant Proteus mirabilis portant sur les facteurs de risque, la pathogénie, le traitement et l'évolution de ces pathologies. Le diagnostic est avant tout microbiologique, la ponction articulaire précoce est réalisée avant toute antibiothérapie, l'examen direct, la culture et l'antibiogramme qui va guider le choix d'une antibiothérapie. L'arthrite septique est une urgence diagnostique et thérapeutique, la prise en charge précoce de cette pathologie permet une guérison sans séquelles.

Pyogenic sacroiliitis in children: two case reports

Pyogenic sacroiliitis is rare and accounts for approximately 1-2% of osteoarticular infections in children. Considerable delay between presentation and diagnosis is recognized. Two cases of pyogenic sacroiliitis are described. The first case is a 28-month-old girl presented with acute onset of fever, pain in the left hip, and limpness. Computed tomography (CT), bone scans, and magnetic resonance imaging (MRI) of the pelvis showed characteristic findings of infectious sacroiliitis, and blood cultures were negatives. The second case is a 13-year-old girl presented with acute onset of fever, pain in the right hip, and buttock, with inability to walk. The diagnosis of pyogenic sacroiliitis was confirmed by bone scans, and CT of the pelvis and blood cultures have identified Proteus mirabilis. The two children recovered fully after 6 weeks of antimicrobial therapy. Pyogenic sacroiliitis is an uncommon disease in children. The key to successful management is early diagnosis in which CT, bone scans, and MRI findings play a crucial role. If the diagnosis is established promptly, most patients can be managed successfully with antimicrobial therapy.

Natural antibiotic susceptibility of Proteus spp., with special reference to P. mirabilis and P. penneri strains

The natural susceptibility of 102 Proteus mirabilis and 35 Proteus penneri strains to 71 antibiotics was examined. Minimum inhibitory concentrations (MICs) were determined by applying a microdilution procedure in IsoSensitest broth (for all strains) and cation-adjusted Mueller Hinton broth (for some strains). P. mirabilis and P. penneri were naturally resistant to penicillin G, oxacillin, all tested macrolides, lincosamides, streptogramins, glycopeptides, rifampicin and fusidic acid. Both species were uniformly, naturally sensitive to all tested aminoglycosides, acylureidopenicillins, some cephalosporins, carbapenems, aztreonam, quinolones, sulfamethoxazole and co-trimoxazole. Species-specific differences in natural susceptibility affecting clinical assessment criteria were seen with tetracyclines, several beta-lactams, chloramphenicol and nitrufurantoin. P. mirabilis was naturally resistant to all tested tetracyclines, and was naturally sensitive to all beta-lactams, except penicillin G and oxacillin. Strains of P. penneri were naturally sensitive or of intermediate susceptibility to tetracyclines, and naturally resistant to amoxicillin (but sensitive or of intermediate susceptibility to aminopenicillins in the presence of beta-lactamase inhibitors) and some cephalosporins (i.e. cefaclor, cefazoline, loracarbef, cefuroxime, cefotiam, and cefdinir). P. penneri was less susceptible than P. mirabilis to chloramphenicol; P. mirabilis was less susceptible than P. penneri to nitrofurantoin. Major medium-dependent influences on the MICs were seen with fosfomycin. The present study describes a database concerning the natural antibiotic susceptibility of P. mirabilis and P. penneri strains to a range of antibiotics, which can be applied to validate forthcoming antibiotic susceptibility tests of these bacteria. It was shown that ten of fifteen amoxicillin-sensitive P. mirabilis strains produced beta-lactamases at a low level, supporting the thesis of the presence of a naturally-occurring beta-lactamase in this species. Natural susceptibility patterns are compared with those of a recent study, dealing with natural susceptibilities of species of the P. vulgaris complex.

Septic sacroiliitis

Two cases of septic sacroiliac (SI) joint arthritis are presented to illustrate the difficulty of diagnosing and treating this uncommon osteoarticular infection. The patients presented are a 68-year-old woman with septic sacroiliitis caused by Streptococcus agalactiae and a 20-year-old man with Salmonella infantis infection involving the SI joint. The recent literature is reviewed and compared with previously published series. Of the 177 cases we reviewed, 47 (27%) occurred in pediatric patients. The mean age was 20 years. Only six patients (3%) were older than 60 years of age. Magnetic resonance imaging (MRI) is most useful for defining extent of infection, osteomyelitis, and abscess formation in the SI joint. Computed tomography (CT) is valuable for defining the extent of bone involvement and for guidance of percutaneous needle arthrocentesis. Other imaging modalities are useful primarily in the initial evaluation of patients with a nonspecific presentation. Four to six weeks of intravenous (i.v.) antibiotic therapy is recommended. Indications for surgical intervention include abscess formation, osteomyelitis, sequestrum of necrotic bone, and failure to respond to i.v. antibiotic therapy.