Cerebral epidural empyema due to Bartonella henselae: a case report.

BACKGROUND: Cat scratch disease frequently involves a benign, self-limited disease. Neurological forms associated with Bartonella henselae are uncommon, consisting mostly in neuroretinitis, encephalitis and meningitis. Cerebral epidural empyema has never described. CASE PRESENTATION: An adult patient was hospitalized for isolated headaches. Magnetic Resonance Imaging (MRI) identified typical features of cerebral epidural empyema. The diagnosis of B. henselae was performed incidentally by 16S rDNA gene sequencing on the abscess fluid, and confirmed by specific qPCR. We report here the first case, to our knowledge, of cerebral epidural empyema associated with B. henselae. Further follow-up visits allowed identifying frequent cat scratches on the scalp as the presumptive source of infection. CONCLUSIONS: This case report alerts about such atypical clinical presentation, which requires an extensive clinical investigation. It also emphasizes on the usefulness of additional molecular diagnosis techniques in such CNS infection cases.

Performance of penicillinase detection tests in Staphylococcus epidermidis: comparison of different phenotypic methods.

BACKGROUND: Staphylococcus epidermidis is the leading coagulase negative staphylococci (CoNS) species associated with healthcare associated infections. In order to de-escalate antimicrobial therapy, isolates of S. epidermidis lacking the blaZ gene should be eligible for targeted antimicrobial therapy. However, testing the susceptibility of coagulase negative staphylococci (CoNS) to penicillin G is no longer recommended by EUCAST, given the low performances for penicillinase detection in CoNS. The objective of this work was to determine a phenotypic method with high performance for detecting penicillinase production in S. epidermidis. RESULTS: Four techniques for the detection of penicillinase production (disk diffusion, zone edge test, nitrocefin test, Minimal Inhibitory Concentration (MIC) by automated system Vitek2®) were evaluated on 182 S. epidermidis isolates, using identification of blaZ gene by PCR as the reference method. The performance of the methods for penicillinase detection was compared by the sensitivity, the specificity, the negative predictive value and the positive predictive value, and with Cohen's kappa statistical test. Among the 182 S. epidermidis included in this study, 55 carried the blaZ gene. The nitrocefin test, characterized by a poor sensitivity (91%), was therefore excluded from S. epidermidis penicillinase detection. The algorithm proposed here for the penicillinase detection in S. epidermidis involved two common antimicrobial susceptibility techniques: disk diffusion method and MIC by Vitek2® system. Disk diffusion method, interpreted with a 26 mm breakpoint for penicillin G, was associated with a high sensitivity (98%) and specificity (100%). This method was completed with zone edge test for S. epidermidis with penicillin G diameter from 26 to 35 mm (sensitivity of 98%). The Vitek2® system is associated with a low sensitivity (93%) and a high specificity (99%) This low sensitivity is associated with false negative results, in isolates with 0.12 mg/L Penicillin G MIC values and blaZ positive. Thus for penicillin G MIC of 0.06 mg/L or 0.12 mg/L, a second step with disc diffusion method is suggested. CONCLUSIONS: According to our results, the strategy proposed here allows the interpretation of penicillin G susceptibility in S. epidermidis isolates, with an efficient detection of penicillin G resistance.

Probabilistic chemotherapy in knee and hip replacement infection: the place of linezolid.

Prosthetic joint infection (PJI) can occur with a wide range of microorganisms and clinical features. After replacement surgery of prosthetic joint, prescription of probabilistic broad-spectrum antimicrobial therapy is usual, while awaiting microbial culture results. The aim of our study was to describe the antibiotic susceptibility of microorganisms isolated from hip and knee PJI. The data were collected to determine the best alternative to the usual combination of piperacillin-tazobactam (TZP) or cefotaxime (CTX) and vancomycin (VAN). Based on a French prospective, multicenter study, we analyzed microbiological susceptibility to antibiotics of 183 strains isolated from patients with confirmed hip or knee PJI. In vitro susceptibility was evaluated: TZP+VAN, TZP+linezolid (LZD), CTX+VAN, and CTX+LZD. We also analyzed resistance to different antibiotics commonly used as oral alternatives. Among the 183 patients with PJI, 62 (34%) had a total knee prosthesis, and 121 (66%) a hip prosthesis. The main identified bacteria were Staphylococcus aureus (32.2% of isolates), coagulase-negative staphylococci (27.3%), Enterobacteriaceae (14.2%), and Streptococcus (13.7%). Infections were polymicrobial for 28 (15.3%) patients. All combinations were highly effective: CTX+VAN, CTX+LZD, TZP+VAN, and TZP+LZD (93.4%, 94%, 98.4%, and 98.9% of all cases respectively). Use of LZD instead of VAN in combination with a broad-spectrum beta-lactam covers almost all of the bacteria isolated in PJI. This association should be considered in probabilistic chemotherapy, as it is particularly easy to use (oral administration and no vancomycin monitoring).

Performance of the extended use of the FilmArray® BCID panel kit for bronchoalveolar lavage analysis.

Ventilator-associated pneumonia (VAP) are responsible for an increase in morbidity, mortality, and prolonged hospital stay. A multiplex PCR kit such as the FilmArray® BCID panel could allow early adaptation of antimicrobial therapy, which is crucial for clinical outcomes. The purpose of this study was to test the performances of FilmArray® BCID panel for the detection of bacteria producing VAP. We tested the FilmArray® BCID panel on 50 bronchoalveolar lavages (BALs), from patients hospitalized in two intensive care units at the Angers university hospital, compared to the conventional culture-based method. The sensitivity and the specificity of the FilmArray® BCID panel were 67.2% and 98.9% respectively. They were 88.6% and 98.3% respectively when considering BALs with a positive culture > 104 CFU/mL, and 94.7% and 99.6% respectively if considering BALs with a positive direct examination. This study underlines the good performance of the FilmArray® BCID panel for BAL fluid analysis. In case of positive direct examination, this test allows reliable results that can be obtained at an early stage, facilitating the early adaptation of antimicrobial therapy.

Histopathological Diagnosis of Prosthetic Joint Infection: Does a Threshold of 23 Neutrophils Do Better than Classification of the Periprosthetic Membrane in a Prospective Multicenter Study?

No gold standard exists for histopathological diagnosis of a prosthetic joint infection (PJI). The historical criterion considers the presence of neutrophil infiltration upon examination of periprosthetic tissue. Morawietz et al. proposed a classification of periprosthetic membranes (Morawietz et al., Clin Pathol 59:591-597, 2006, https://doi.org/10.1136/jcp.2005.027458) and a more recently described classification with a new cutoff value of 23 neutrophils in 10 high-power fields (Morawietz et al., Histopathology 54:847-853, 2009. https://doi.org/10.1111/j.1365-2559.2009.03313.x). We performed a multicenter prospective study, which compared both methods for the diagnosis of PJI. All suspicions of PJI (n = 264) between December 2010 and March 2012 in seven centers were prospectively included. Five perioperative specimens were collected per patient for cultures, and one was collected for histology. Diagnosis of PJI was made according to the Infectious Diseases Society of America (IDSA) guidelines. Histopathological analysis classified the patients according to the threshold of 23 neutrophils and according to the classification of Morawietz. Performances of both methods were compared by using clinical and/or bacteriological criteria as the gold standard. Among 264 patients with suspected PJI, a diagnosis of infection was confirmed in 215 and unconfirmed in 49 patients. Histopathological analysis was available for 150 confirmed PJI and 40 unconfirmed PJI cases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 78.7%, 90.0%, 96.7%, 52.9%, and 81.1%, respectively, for the Morawietz classification, and 82.0%, 90.0%, 96.9%, 57.1%, and 83.7%, respectively, for the 23-neutrophil threshold. The new algorithm using a threshold of 23 neutrophils can be proposed as a new gold standard for the histopathological diagnosis of PJI.

How Many Samples and How Many Culture Media To Diagnose a Prosthetic Joint Infection: a Clinical and Microbiological Prospective Multicenter Study.

Although numerous perioperative samples and culture media are required to diagnose prosthetic joint infection (PJI), their exact number and types have not yet been definitely determined with a high level of proof. We conducted a prospective multicenter study to determine the minimal number of samples and culture media required for accurate diagnosis of PJI. Over a 2-year period, consecutive patients with clinical signs suggesting PJI were included, with five perioperative samples per patient. The bacteriological and PJI diagnosis criteria were assessed using a random selection of two, three, or four samples and compared with those obtained using the recommended five samples (references guidelines). The results obtained with two or three culture media were then compared with those obtained with five culture media for both criteria. The times-to-positivity of the different culture media were calculated. PJI was confirmed in 215/264 suspected cases, with a bacteriological criterion in 192 (89%). The PJI was monomicrobial (85%) or polymicrobial (15%). Percentages of agreement of 98.1% and 99.7%, respectively, for the bacteriological criterion and confirmed PJI diagnosis were obtained when four perioperative samples were considered. The highest percentages of agreement were obtained with the association of three culture media, a blood culture bottle, a chocolate agar plate, and Schaedler broth, incubated for 5, 7, and 14 days, respectively. This new procedure leads to significant cost saving. Our prospective multicenter study showed that four samples seeded on three culture media are sufficient for diagnosing PJI.

First experience of a multicenter external quality assessment of molecular 16S rRNA gene detection in bone and joint infections.

The objective of this study was to assess the performance of seven French laboratories for 16S rRNA gene detection by real-time PCR in the diagnosis of bone and joint infection (BJI) to validate a large multicenter study. External quality control (QC) was required owing to the differences in extraction procedures and the molecular equipment used in the different laboratories. Three proficiency sets were organized, including four bacterial DNA extracts and four bead mill-pretreated osteoarticular specimens. Extraction volumes, 16S rRNA gene primers, and sequencing interpretation rules were standardized. In order to assess each laboratory's ability to achieve the best results, scores were assigned, and each QC series was classified as optimal, acceptable, or to be improved. A total of 168 QCs were sent, and 160 responses were analyzed. The expected results were obtained for 93.8%, with the same proportion for extracts (75/80) and clinical specimens (75/80). For the specimens, there was no significant difference between manual and automated extraction. This QC demonstrated the ability to achieve good and homogeneous results using the same 16S rRNA gene PCR with different equipment and validates the possibility of high-quality multicenter studies using molecular diagnosis for BJI.

First report of endocarditis caused by a Pseudoclavibacter species.

We describe the first case of Pseudoclavibacter species endocarditis in a 44-year-old patient. This genus, rarely isolated from humans, confirms here its role as a human pathogen.

Evaluation of 16S rRNA gene PCR sensitivity and specificity for diagnosis of prosthetic joint infection: a prospective multicenter cross-sectional study.

There is no standard method for the diagnosis of prosthetic joint infection (PJI). The contribution of 16S rRNA gene PCR sequencing on a routine basis remains to be defined. We performed a prospective multicenter study to assess the contributions of 16S rRNA gene assays in PJI diagnosis. Over a 2-year period, all patients suspected to have PJIs and a few uninfected patients undergoing primary arthroplasty (control group) were included. Five perioperative samples per patient were collected for culture and 16S rRNA gene PCR sequencing and one for histological examination. Three multicenter quality control assays were performed with both DNA extracts and crushed samples. The diagnosis of PJI was based on clinical, bacteriological, and histological criteria, according to Infectious Diseases Society of America guidelines. A molecular diagnosis was modeled on the bacteriological criterion (≥ 1 positive sample for strict pathogens and ≥ 2 for commensal skin flora). Molecular data were analyzed according to the diagnosis of PJI. Between December 2010 and March 2012, 264 suspected cases of PJI and 35 control cases were included. PJI was confirmed in 215/264 suspected cases, 192 (89%) with a bacteriological criterion. The PJIs were monomicrobial (163 cases [85%]; staphylococci, n = 108; streptococci, n = 22; Gram-negative bacilli, n = 16; anaerobes, n = 13; others, n = 4) or polymicrobial (29 cases [15%]). The molecular diagnosis was positive in 151/215 confirmed cases of PJI (143 cases with bacteriological PJI documentation and 8 treated cases without bacteriological documentation) and in 2/49 cases without confirmed PJI (sensitivity, 73.3%; specificity, 95.5%). The 16S rRNA gene PCR assay showed a lack of sensitivity in the diagnosis of PJI on a multicenter routine basis.

Impact of a strategy based on unique blood culture sampling on contamination rate and detection of bloodstream infections in critically ill patients.

BACKGROUND: Unique blood culture (UBC) has been proposed to limit the number of venipuncture and to decrease the risk of BC contaminations (BCC) without affecting their yield. We hypothesized that a multi-faceted program based on UBC in the ICU may reduce the rate of contaminants with a similar performance for bloodstream infections (BSI) identification. METHODS: In a before and after design, we compared the proportion of BSI and BCC. A first 3-year period with multi-sampling (MS) strategy followed by a 4-month washout period, where staff received education and training for using UBC, and a 32-month period, where UBC was routinely used, while education and feedback were maintained. During the UBC period, a large volume of blood (40 mL) was sampled through a unique venipuncture with additional BC collections discouraged for 48 h. RESULTS: Of the 4,491 patients included (35% female patients, mean age 62 years) 17,466 BC were collected. The mean volume of blood per bottle collected increased from 2.8 ± 1.8 mL to 8.2 ± 3.9 mL between the MS and UBC periods, P < 0.01. A 59.6% reduction (95% CI 56.7-62.3; P < 0.001) of BC bottles collected per week was observed between the MS and UBC periods. The rate of BCC per patient decreased between the two periods from 11.2% to 3.8% (73.4% reduction; P < 0.001) for the MS and UBC periods, P < 0.001. Meanwhile, the rate of BSI per patient remained stable at 13.2% and 13.2% for the MS and UBC periods, P = 0.98. CONCLUSIONS: In ICU patients, a strategy based on UBC reduces the contamination rate of cultures without affecting their yield.

BIOFIRE® Blood Culture IDentification 2 (BCID2) panel for early adaptation of antimicrobial therapy in adult patients with bloodstream infections: a real-life experience.

Our objective was to assess the effectiveness of a multiplex PCR panel for blood culture identification (BCID2) on the implementation of appropriate antimicrobial therapy. We conducted a monocentric pre/post study comparing the time to result from direct microscopic examination (DE) to bacterial identification (BI) in positive blood cultures between 2 different periods: P1 without BCID2 and P2 with BCID2. Appropriate treatments prescribed before DE and after DE / BCID2 and after BI / BCID2 were compared using direct proportion comparison and survival analysis. For mono-microbial bloodstream infections, the proportion of appropriate antimicrobial treatment after DE was 50% in P1 vs. 87.5% after BCID2 in P2 (P < 0.001) for Gram-negative bacteria and 33.0% in P1 vs. 64.4% in P2 (P < 0.01) for Gram-positive bacteria. A significant difference (P = 0.04) was recorded with survival curves for Gram positive bacteria. BCID2 seems effective in reducing the time for prescribing appropriate antimicrobials.

Clinical, Bacteriological, and Genetic Characterization of Bone and Joint Infections Involving Linezolid-Resistant Staphylococcus epidermidis: a Retrospective Multicenter Study in French Reference Centers.

The choice of the best probabilistic postoperative antibiotics in bone and joint infections (BJIs) is still challenging. Since the implementation of protocolized postoperative linezolid in six French referral centers, linezolid-resistant multidrug-resistant Staphylococcus epidermidis (LR-MDRSE) strains were isolated in patients with BJI. We aimed here to describe clinical, microbiological, and molecular patterns associated with these strains. All patients with at least one intraoperative specimen positive for LR-MDRSE between 2015 and 2020 were included in this retrospective multicenter study. Clinical presentation, management, and outcome were described. LR-MDRSE strains were investigated by MIC determination for linezolid and other anti-MRSA antibiotics, characterization of genetic determinants of resistance, and phylogenetic analysis. Forty-six patients (colonization n = 10, infection n = 36) were included in five centers, 45 had prior exposure to linezolid, 33 had foreign devices. Clinical success was achieved for 26/36 patients. Incidence of LR-MDRSE increased over the study period. One hundred percent of the strains were resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, and susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. Molecular analysis was performed for 44 strains, and the main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. We showed the emergence of new clonal populations of highly linezolid-resistant S. epidermidis in BJIs. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use are essential. IMPORTANCE The manuscript describes the emergence of clonal linezolid-resistant strains of Staphylococcus epidermidis (LR-MDRSE) isolated from patients presenting with bone and joint infections. Incidence of LR-MDRSE increased over the study period. All strains were highly resistant to oxazolidinones, gentamicin, clindamycin, ofloxacin, rifampicin, ceftaroline, and ceftobiprole, but were susceptible to cyclins, daptomycin, and dalbavancin. Susceptibility to delafloxacin was bimodal. The main mutation conferring linezolid resistance was the 23S rRNA G2576T mutation. All strains belonged to the sequence type ST2 or its clonal complex, and phylogenetic analysis showed emergence of five populations corresponding geographically to the centers. LR-MDRSE bone and joint infections seem to be accompanied by an overall poor prognosis related to comorbidities and therapeutic issues. Identifying patients at risk for LR-MDRSE acquisition and proposing alternatives to systematic postoperative linezolid use become essential, with a preference for parenteral drugs such as lipopeptids or lipoglycopeptids.

Multicentric evaluation of BioFire FilmArray Pneumonia Panel for rapid bacteriological documentation of pneumonia.

OBJECTIVES: To evaluate performances of the rapid multiplex PCR assay BioFire FilmArray Pneumonia Panel (FA-PP) for detection of bacterial pathogens and antibiotic resistance genes in sputum, endotracheal aspirate (ETA) and bronchoalveolar lavage (BAL) specimens. METHODS: This prospective observational study was conducted in 11 French university hospitals (July to December 2018) and assessed performance of FA-PP by comparison with routine conventional methods. RESULTS: A total of 515 respiratory specimens were studied, including 58 sputa, 217 ETA and 240 BAL. The FA-PP detected at least one pathogen in 384 specimens, yielding an overall positivity rate of 74.6% (384/515). Of them, 353 (68.5%) specimens were positive for typical bacteria while eight atypical bacteria and 42 resistance genes were found. While identifying most bacterial pathogens isolated by culture (374/396, 94.4%), the FA-PP detected 294 additional species in 37.7% (194/515) of specimens. The FA-PP demonstrated positive percentage agreement and negative percentage agreement values of 94.4% (95% CI 91.7%-96.5%) and 96.0% (95% CI 95.5%-96.4%), respectively, when compared with culture. Of FA-PP false-negative results, 67.6% (46/68) corresponded to bacterial species not included in the panel. At the same semi-quantification level (in DNA copies/mL for FA-PP versus in CFU/mL for culture), the concordance rate was 43.4% (142/327) for culture-positive specimens with FA-PP reporting higher semi-quantification of ≥1 log10 in 48.6% (159/327) of cases. Interestingly, 90.1% of detected bacteria with ≥106 DNA copies/mL grew significantly in culture. CONCLUSIONS: FA-PP is a simple and rapid molecular test that could complement routine conventional methods for improvement of diagnosis accuracy of pneumonia.

High prevalence of contamination of sink drains with carbapenemase-producing Enterobacteriaceae in 4 intensive care units apart from any epidemic context.

We report a high prevalence (28%) of sink drains contaminated with carbapenemase-producing Enterobacteriaceae (CPE) in 4 intensive care units with a history of CPE carriage in hospitalized patients within the previous 5 years, but apart from any current epidemic context. Carbapenemase genes, particularly blaVIM and blaNDM, were identified by polymerase chain reaction in sink drains in which no CPE was detected, but very few data are available in the literature concerning their presence in sink drains.

Assessment of a Multiplex Serological Test for the Diagnosis of Prosthetic Joint Infection: a Prospective Multicentre Study.

Introduction: The diagnosis of prosthetic joint infections (PJIs) can be difficult in the chronic stage and is based on clinical and paraclinical evidence. A minimally invasive serological test against the main pathogens encountered during PJI would distinguish PJI from mechanical loosening. Methods: We performed a prospective, multicentre, cross-sectional study to assess the contribution of serology in the diagnosis of PJI. Over a 2-year period, all patients undergoing prosthesis revision were included in the study. A C-reactive protein assay and a serological test specifically designed against 5 bacterial species (Staphylococcus aureus, S. epidermidis, S. lugdunensis, Streptococcus agalactiae, Cutibacterium acnes) were performed preoperatively. Five samples per patient were taken intraoperatively during surgery. The diagnosis of PJI was based on clinical and bacteriological criteria according to guidelines. Results: Between November 2015 and November 2017, 115 patients were included, 49 for a chronic PJI and 66 for a mechanical problem. Among patients with PJI, a sinus tract was observed in 32.6% and a C-reactive protein level ≥10 mg/L in 74.5%. The PJI was monomicrobial in 43 cases (targeted staphylococci, 24; S. agalactiae, 1; C. acnes, 2; others, 16), and polymicrobial in 6 cases (12.2%). Sensitivity, specificity, positive predictive value and negative predictive value were 75.0%, 82.1%, 58.3% and 90.8%, respectively, for targeted staphylococci. Specificity/negative predictive value was 97.3%/100% for S. agalactiae and 83.8% /96.9% for C. acnes. Conclusions: The serological tests are insufficient to affirm the diagnosis of PJI for the targeted bacteria. Nevertheless, the excellent NPV may help clinicians to exclude PJI.

A case of Ureaplasma parvum meningitis in an adult after transphenoidal ablation of craniopharyngioma.

We report the case of a Ureaplasma parvum meningitis in an immunocompetent patient, 17 days after surgical ablation of a craniopharyngioma. Presence of U. parvum in the cerebrospinal fluid was assessed by 16S rDNA sequencing and U. parvum specific PCR. This article details a surprising complication in an adult of a transphenoidal surgery for ablation of a craniopharyngioma. This is the first case, to our knowledge, of U. parvum meningitis in an adult patient.

The Right Time to Safely Re-Evaluate Empirical Antimicrobial Treatment of Hip or Knee Prosthetic Joint Infections.

Currently, no guideline provides recommendations on the duration of empirical antimicrobial treatment (EAT) in prosthetic joint infection (PJI). The aim of our study was to describe the time to growth of bacteria involved in PJI, rendering possible decreased duration of EAT. Based on a French multicentre prospective cohort study, culture data from patients with confirmed hip or knee PJI were analysed. For each patient, five samples were processed. Time to positivity was defined as the first positive medium in at least one sample for virulent pathogens and as the first positive medium in at least two samples for commensals. Definitive diagnosis of polymicrobial infections was considered the day the last bacteria were identified. Among the 183 PJIs, including 28 polymicrobial infections, microbiological diagnosis was carried out between Day 1 (D1) and D5 for 96.7% of cases. There was no difference in the average time to positivity between acute and chronic PJI (p = 0.8871). Microbiological diagnosis was given earlier for monomicrobial than for polymicrobial infections (p = 0.0034). When an optimized culture of peroperative samples was carried out, almost all cases of PJI were diagnosed within five days, including polymicrobial infections. EAT can be re-evaluated at D5 according to microbiological documentation.

A rare case of Prosthetic Joint Infection associated with Coxiella burnetii.

We report here the case of a Prosthetic Joint Infection (PJI) associated with Coxiella burnetii in a 62-year-old man with a revised total hip arthroplasty. The diagnosis was performed first by 16S rDNA sequencing on hip fluid aspirate, and confirmed by specific qPCR. Q fever has been reported in few cases of Prosthetic Joint Infections, often associated with chronic evolution and iterative surgeries. This case report alerts about such an unexpected diagnosis in a patient with no known risk factors.

The prognosis of streptococcal prosthetic bone and joint infections depends on surgical management-A multicenter retrospective study.

BACKGROUND: The optimal treatment of streptococcal prosthetic joint infections (PJIs) is unclear. METHODS: A cohort of streptococcal PJIs was reviewed retrospectively in seven reference centers for the management of complex bone and joint infections, covering the period January 1, 2010 to December 31, 2012. RESULTS: Seventy patients with monomicrobial infections were included: 47 had infections of total hip arthroplasty and 23 had infections of total knee arthroplasty. The median age was 77 years (interquartile range (IQR) 69-83 years), the median Charlson comorbidity score was 4 (IQR 3-6), and 15.6% (n=11) had diabetes. The most commonly identified streptococcal species were Streptococcus agalactiae and Streptococcus dysgalactiae (38.6% (n=27) and 17.1% (n=12), respectively). Debridement, antibiotics and implant retention (DAIR) was performed after a median time of 7 days (IQR 3-8 days), with polyethylene exchange (PE) in 21% of cases. After a minimum follow-up of 2 years, 27% of patients had relapsed, corresponding to 51.4% of DAIR treatment cases and 0% of one-stage (n=15) or two-stage (n=17) exchange strategy cases. Rifampicin or levofloxacin in combination therapy was not associated with a better outcome (adjusted p= 0.99). S. agalactiae species and DAIR treatment were associated with a higher risk of failure. On multivariate analysis, only DAIR treatment and S. agalactiae were independent factors of relapse. Compared to DAIR without PE, DAIR with PE was only associated with a trend towards a benefit (odds ratio 0.33, 95% confidence interval 0.06-1.96; adjusted p= 0.44). CONCLUSIONS: Streptococcal PJIs managed with DAIR have a poor prognosis and S. agalactiae seems to be an independent factor of treatment failure.

Staphylococcus saprophyticus: Which beta-lactam?

BACKGROUND: Staphylococcus saprophyticus is resistant to the drugs most often used for the empirical treatment of urinary tract infections (UTI). The adequacy of antimicrobial treatments prescribed for UTI due to S. saprophyticus is not usually questioned. This study described the epidemiology of such infections and assessed the susceptibility of S. saprophyticus to ceftriaxone and amoxicillin-clavulanic acid. METHODS: Methicillin-susceptible S. saprophyticus (MSSS) isolated from clinical samples between November 2014 and July 2016 were included. Clinical data were recorded. The minimum inhibitory concentrations (MICs) of amoxicillin-clavulanic acid and ceftriaxone were measured for these MSSS strains and for 17 randomly selected methicillin-susceptible Staphylococcus aureus (MSSA) strains. RESULTS: Of the S. saprophyticus isolates from urine, 59.5% were associated with a diagnosis of cystitis and 33.3% with pyelonephritis. Sixty percent of S. saprophyticus cystitis cases and 25% of pyelonephritis cases were given an inappropriate antibiotic regimen. The MICs of ceftriaxone ranged from 4 to >32µg/ml for MSSS, and from 1.5 to 4µg/ml for MSSA. CONCLUSIONS: Many UTIs were treated with an empirical antibiotic therapy that was ineffective for S. saprophyticus, revealing that S. saprophyticus is an aetiology that is insufficiently considered in UTI. High MICs for ceftriaxone in MSSS were observed, which raises questions about the use of this antibiotic in UTIs due to S. saprophyticus.