Tolerability of prolonged linezolid therapy in bone and joint infection: protective effect of rifampicin on the occurrence of anaemia?

Cerebrospinal Fluid Shunt Infections

Cerebrospinal fluid (CSF) shunt infections are a particularly challenging clinical problem. This review article addresses epidemiology and microbiology of CSF shunt infections. Clinical care is reviewed in detail, including recent guidelines and systematic review articles. Finally, current research into prevention and treatment is highlighted, with a discussion on the mechanisms of infection.

Rifampicin reduces plasma concentration of linezolid in patients with infective endocarditis

BACKGROUND

Linezolid in combination with rifampicin has been used in treatment of infective endocarditis especially for patients infected with staphylococci.

OBJECTIVES

Because rifampicin has been reported to reduce the plasma concentration of linezolid, the present study aimed to characterize the population pharmacokinetics of linezolid for the purpose of quantifying an effect of rifampicin cotreatment. In addition, the possibility of compensation by dosage adjustments was evaluated.

PATIENTS AND METHODS

Pharmacokinetic measurements were performed in 62 patients treated with linezolid for left-sided infective endocarditis in the Partial Oral Endocarditis Treatment (POET) trial. Fifteen patients were cotreated with rifampicin. A total of 437 linezolid plasma concentrations were obtained. The pharmacokinetic data were adequately described by a one-compartment model with first-order absorption and first-order elimination.

RESULTS

We demonstrated a substantial increase of linezolid clearance by 150% (95% CI: 78%-251%), when combined with rifampicin. The final model was evaluated by goodness-of-fit plots showing an acceptable fit, and a visual predictive check validated the model. Model-based dosing simulations showed that rifampicin cotreatment decreased the PTA of linezolid from 94.3% to 34.9% and from 52.7% to 3.5% for MICs of 2 mg/L and 4 mg/L, respectively.

CONCLUSIONS

A substantial interaction between linezolid and rifampicin was detected in patients with infective endocarditis, and the interaction was stronger than previously reported. Model-based simulations showed that increasing the linezolid dose might compensate without increasing the risk of adverse effects to the same degree.

Evaluation of the impact of rifampicin on the plasma concentration of linezolid in tuberculosis co-infected patients

Linezolid combined with rifampicin has shown excellent clinical outcomes against infection by multi-resistant Gram-positive bacteria. However, several studies have indicated that rifampicin reduces the plasma concentration of linezolid in patients with severe infection. Linezolid has been recommended for the treatment of patients with multidrug-resistant or extensively drug-resistant tuberculosis. However, studies on the interaction between linezolid and rifampicin in patients suffering from tuberculosis with infection are lacking. We evaluated the interaction between linezolid and rifampicin based on therapeutic drug monitoring (TDM). A retrospective analysis was undertaken for patients with tuberculosis and infection who were treated with linezolid and undergoing TDM. Patients were divided into the linezolid group and linezolid + rifampicin group. Data on demographic characteristics, disease, duration of linezolid therapy, and the plasma concentration of linezolid were used for statistical analyses. Eighty-eight patients with tuberculosis and infection were assessed. Values for the peak (Cmax) and trough (Cmin) concentrations of linezolid in plasma were available for 42 and 46 cases, respectively. Patients in the linezolid group had a significantly higher Cmax [15.76 (8.07-26.06) vs. 13.18 (7.48-23.64) mg/L, p = 0.048] and Cmin [8.38 (3.06-16.53) vs. 4.27 (0.45-10.47), p = 0.005] than those in the linezolid + rifampicin group. The plasma concentration of linezolid increased obviously in two patients after rifampicin discontinuation. However, the total efficiency and prevalence of hematologic adverse reactions were not significantly different in the linezolid group and linezolid + rifampin group. The plasma concentration of linezolid decreased upon combination with rifampicin, suggesting that TDM may aid avoidance of subtherapeutic levels of linezolid upon co-treatment with rifampicin.

Prolonged use of linezolid in bone and joint infections: a retrospective analysis of adverse effects

OBJECTIVES

Antibiotic treatment for bone and joint infections generally lasts for 6 weeks or longer. Linezolid may be a good option for treating bone and joint infections, but there is an increased risk of potential serious adverse drug events (ADEs) when used for more than 28 days. The aim of this study was to obtain detailed information on the type and time to occurrence of the patient-reported ADEs, the dynamics of haematopoiesis over time, and the reasons for early discontinuation of linezolid when used for an intended maximum duration of 12 weeks.

METHODS

This single-centre retrospective study was conducted at the Sint Maartenskliniek in The Netherlands. Patients were included if they were planned to use linezolid for more than 28 days. The main reason for discontinuation of linezolid, the ADE according to the Naranjo score, and the time to occurrence of ADEs were analysed.

RESULTS

Among 78 patients, drug toxicity led to early discontinuation of linezolid in 11 (14%) patients before and nine (12%) after 28 days of therapy. The median treatment duration was 42 days. Gastrointestinal intolerance (42%) and malaise (32%) were the most common ADEs. In 75% of the cases the ADE occurred within 28 days of therapy. Sixty-seven patients were able to continue linezolid beyond 28 days, 87% of whom completed therapy as scheduled. Severe cytopenia, according to the Common Terminology Criteria for Adverse events (CTCA), was observed in four patients and was reversible after discontinuation of linezolid. One patient suffered optic neuropathy related to linezolid use.

CONCLUSIONS

Linezolid could be considered an alternative option to the current standard of IV glycopeptides for the treatment of bone and joint infection for up to 12 weeks. If patients pass the first 28 days of therapy, the likelihood of successful completion of therapy is high with a low risk of serious ADEs.

Two-Stage Revision Arthroplasty for Resistant Gram-Positive Periprosthetic Joint Infections Using an Oral Linezolid-Based Antibiotic Regime

BACKGROUND

Increasing antibiotic resistance has been reported as an issue in the systemic treatment of periprosthetic joint infection (PJI). Linezolid offers the advantages of high oral bioavailability and little resistance; however, efficacy in the treatment of PJI varies considerably, and studies reporting consistent surgical treatment are scarce.

METHODS

This is a retrospective, single-center analysis of two-stage revisions performed between 2008 and 2017. We identified 111 patients who met the inclusion criteria. Oral linezolid was given for 28 days following 14 days of intravenous tailored antibiotics in resistant gram-positive PJI. A total of 64% of the patients had methicillin-resistant coagulase-negative staphylococci. The median follow-up was 43 (interquartile range (IQR) 30-57) months.

RESULTS

22% (24/111) of the patients underwent surgery for subsequent infection. The 5-year infection-free survival probability was 77% (95% confidence interval (CI) 69-85). A total of 5% of the patients (6/111) had the same organism at the time of reinfection. The patients with infections caused by other organisms than Coagulase-negative staphylococci tended to have a worse reinfection-free survivorship at five years (70% vs. 81%, p = 0.09). Furthermore, the patients with obesity tended to have reduced reinfection-free survivorship at five years (69% vs. 84%, p = 0.08). Overall, 5% (6/111) of the patients had blood count abnormalities with no treatment discontinuations.

CONCLUSION

Two-stage revision arthroplasty with systemic oral linezolid treatment for resistant gram-positive PJI results in an infection control of 77% at the mid-term.

Comparative efficacy of dalbavancin alone and with rifampicin against in vitro biofilms in a pharmacodynamic model with methicillin-resistant Staphylococcus aureus

BACKGROUND

The anti-biofilm efficacy of dalbavancin has been evaluated in static models. Using an in vitro pharmacokinetic/pharmacodynamic model, we evaluated the comparative activity of dalbavancin alone and with rifampicin against biofilm-embedded methicillin-resistant S. aureus (MRSA).

METHODS

Two MRSA strains (HUB-4/HUB-5) were evaluated with the Calgary Device System and the dynamic CDC-Biofilm Reactor over 144 h. Dosage regimens simulated the human pharmacokinetics of dalbavancin (1500mg, single dose), vancomycin (1000mg/12 h) and linezolid (600mg/12 h), alone and with rifampicin (600mg/24 h). Efficacy was evaluated by assessing log10 CFU/mL changes (ΔlogCFU/mL) and we screened for resistance.

RESULTS

The minimal biofilm inhibitory/eradication concentrations of dalbavancin were 0.25/16 mg/L (HUB-4) and 0.25/8mg/L (HUB-5), respectively. In the pharmacokinetic/pharmacodynamic analysis, dalbavancin alone showed limited efficacy, but without resistance developing. Adding rifampicin improved the activities of dalbavancin, vancomycin, and linezolid, but rifampicin-resistant strains appeared over time in all cases. Dalbavancin-rifampicin was bactericidal against HUB-4 in the absence of resistance at 72 h and 144 h (ΔlogCFU/mL: -3.54±0.83, -4.32±0.12, respectively), an effect that was only achieved by linezolid-rifampicin at 144h (-3.33 ± 0.66). Against HUB-5, dalbavancin-rifampicin activity was impaired by rifampicin resistance to a greater extent than other combinations and had no bactericidal effect.

CONCLUSIONS

The anti-biofilm efficacy of dalbavancin was improved significantly by adding rifampicin. Although no dalbavancin resistance occurred, rifampicin resistance appeared in all combination therapies and decreased their efficacy over time. Dalbavancin-rifampicin in vitro treatment appears as promising anti-biofilm therapy, but further studies should evaluate the in vivo efficacy and the risk of resistance.

Linezolid-Induced Pure Red Cell Aplasia: A Case Report

Linezolid (LZD) has been widely used for treating the infections of multidrug-resistant gram-positive organisms. As we know, anemias induced by Linezolid (LZD) are common. However, LZD-induced pure red cell aplasia (PRCA) is very rare. In this paper, we report on a 68-year-old woman with intravascular stent infection who developed PRCA after treatment with LZD. The patient presented to our hospital with a 6-month history of fever after stent implantation for aneurysms in both lower limbs. Bone culture grew methicillin-resistant Staphylococcus hemolyticus (MRSH). She received LZD after developing adverse reactions to initial antibiotics. Although her infective symptoms were improved by LZD, progressive thrombocytopenia was observed 23 days after LZD therapy. Her platelets declined to 66*10⁹/L and hemoglobin level was 10.1 g/dL. Thrombocytopenia recovered 12 days after cessation of LZD. LZD was administered again due to recovered fever. 57 days after LZD administration, her hemoglobin level was 4.1 g/dL and reticulocytes were 0.2%. Bone marrow smear revealed active granulocyte proliferation and markedly decreased erythropoiesis with vacuolar degeneration. 12 days after cessation of LZD, her hemoglobin and reticulocyte levels rose to 9.6 g/dL and 5.1%, respectively. LZD was used for the third time as fever and inflammatory markers progressively increased, but Hb was reduced to 6.7g/dL 15 days after LZD therapy. 12 days after cessation of LZD, the hemoglobin level rose to 11.9 g/dL. In summary, we suggest complete blood count and reticulocyte count should be monitored to detect bone marrow suppression during long-term LZD therapy, especially in patients aged over 58 and/or with pre-existing anemia, chronic infections, and renal insufficiency.

Real-World Use of Tedizolid Phosphate for 28 Days or More: A Case Series Describing Tolerability and Clinical Success

Tedizolid has activity against Gram-positive pathogens as well as Mycobacterium spp and Nocardia spp. Real-world evidence supporting long-term tolerability and clinical success of tedizolid is lacking. Prolonged tedizolid therapy (median, 188 days; interquartile range, 62-493 days) appeared to be well tolerated in 37 patients (8.1% experienced adverse effect leading to discontinuation). Clinical success was 81.3% in those evaluated.

Correction of thrombocytopenia caused by linezolid with scheduled sequential tedizolid use in patients with vertebral osteomyelitis by antibiotic resistant Gram-positive organisms

INTRODUCTION

Because of thrombocytopenia, linezolid treatment tends to be stopped before the completion of therapy for complicated infections that require prolonged antimicrobial administration. In contrast, tedizolid shows a favorable hematologic profile. The primary end-point of this study was to evaluate the efficacy of switching treatment to tedizolid in patients who developed thrombocytopenia during linezolid therapy.

METHODS

This retrospective study was conducted in patients with vertebral osteomyelitis (VO) caused by antibiotic-resistant Gram-positive bacteria. Treatment failure was defined as the reappearance of infection signs within 2 weeks after stopping tedizolid and discontinuation of tedizolid because of continued thrombocytopenia or other adverse effects.

RESULTS

Eight patients with native VO (n = 3) and postoperative VO (n = 5) were included in the study. The causative organisms were MRSA in all patients except one. Platelet counts decreased from 35.2 ± 11.5 × 10⁴/mm³ to 17.8 ± 6.2 × 10⁴/mm³ during linezolid therapy and improved without washout period in all patients after switching to tedizolid on days 5-7 (28.6 ± 4.9 × 10⁴/mm³, p = 0.002). Tedizolid therapy was completed and treatment failure was not observed in any patient. The duration of treatment was 20.0 ± 11.2 days for linezolid and 30.3 ± 9.5 days for tedizolid (total, 50.3 ± 10.7 days). One patient died because of underlying disease, and there was no recurrence in the remaining 7 patients (median follow-up 501 days).

CONCLUSIONS

Switching therapy to tedizolid improved thrombocytopenia that occurred during linezolid therapy, and it enabled the completion of therapy for VO patients.

Enhanced loading dose of teicoplanin for three days is required to achieve a target trough concentration of 20 μg/mL in patients receiving continuous venovenous haemodiafiltration with a low flow rate

INTRODUCTION

Because of its lower risk of renal toxicity than vancomycin, teicoplanin is the preferred treatment for methicillin-resistant Staphylococcus aureus infection in patients undergoing continuous venovenous haemodiafiltration (CVVHDF) in whom renal function is expected to recover. The dosing regimen for achieving a trough concentration (C_min) of ≥20 μg/mL remains unclear in patients on CVVHDF using the low flow rate adopted in Japan.

METHODS

The study was conducted in patients undergoing CVVHDF with a flow rate of <20 mg/kg/h who were treated with teicoplanin. We adopted three loading dose regimens for the initial 3 days: the conventional regimen, a high-dose regimen (four doses of 10 mg/kg), and an enhanced regimen (four doses of 12 mg/kg). The initial C_min was obtained at 72 h after the first dose.

RESULTS

Overall, 60 patients were eligible for study inclusion. The proportion of patients achieving the C_min target was significantly higher for the enhanced regimen than for the high-dose regimen (52.9% versus 8.3%, p = 0.003). In multivariate analysis, the enhanced regimen (odds ratio [OR] = 39.93, 95% confidence interval [CI] = 5.03-317.17) and hypoalbuminaemia (OR = 0.04, 95% CI = 0.01-0.44) were independent predictors of the achievement of C_min ≥ 20 μg/mL.

CONCLUSIONS

An enhanced teicoplanin regimen was proposed to treat complicated or invasive infections by methicillin-resistant Staphylococcus aureus in patients receiving CVVHDF even with a low flow rate.

A risk factor-based predictive model for linezolid-induced anaemia: A 7-year retrospective study

WHAT IS KNOWN AND OBJECTIVE

The primary adverse reaction of linezolid is haematological toxicity, leading to thrombocytopenia and anaemia. This study aimed to investigate the risk factors of linezolid-induced anaemia (LI-AN) and establish a predictive model by multivariate logistic regression model analysis to predict LI-AN risks in Chinese adult patients.

METHODS

Demographic and clinical data of patients who underwent linezolid therapy for more than three days between January 2014 and December 2020 in Zhongshan Hospital, Fudan University, were retrieved from the hospital's electronic medical record for analysis. Multivariate logistic regression analysis was employed to establish a predictive model, whose predictability was further evaluated by the area under the receiver operating characteristic (ROC) curve.

RESULTS AND DISCUSSION

The study comprised 298 patients among the 2322 patients who underwent linezolid treatment between 2014 and 2020. Among the 298 patients, 32 (10.7%) developed anaemia with an average of 11.4 (SD 6.2) days after the initiation of linezolid therapy. Multivariate logistic analysis revealed that age ≥60 years (odds ratio [OR] 2.815, 95% confidence interval [CI] 1.242-6.379), higher total bilirubin (TBi) (OR 1.031, 95% CI 1.011-1.051), eGFR < 60 ml/(min·1.73 m² ) (OR 2.537, 95% CI 1.054-6.106), duration of linezolid therapy (DLT) (OR 1.091, 95% CI 1.023-1.163) and intensive care unit (ICU) admittance (OR 2.664, 95% CI 1.150-6.174) were the independent risk factors for anaemia occurrence among patients receiving linezolid therapy. A logistic regression equation based on the five risk factors was subsequently established and transformed to obtain the calculation formula of the combined predictor: Y_{(Combined predictor)}  = X_TBi  + 34.5 × X_Age≥60  + 31.1 × X_eGFR<60  + 32.7 × X_ICU  + 2.9 × X_DLT , (where Age ≥60 years, yes = 1, no = 0; eGFR < 60 ml/(min·1.73 m² ), yes = 1, no = 0; ICU admittance, yes = 1, no = 0). The area under the ROC curve of the combined predictors equation was 0.773 with an optimal cut-off point value of 92.4, corresponding to a 75.0% sensitivity and 76.7% specificity.

WHAT IS NEW AND CONCLUSION

LI-AN is associated with age (≥60 years), higher TBi, eGFR < 60 ml/(min·1.73 m² ), DLT and ICU admittance. Physicians should thus calculate the combined predictor value at the beginning of linezolid treatment to predict and evaluate the risk of LI-AN. An optimal cut-off value larger than 92.4 indicates that the patient has a higher LI-AN risk. As such, Hb levels should be monitored regularly, and dosage regimens adjusted accordingly to prevent anaemia occurrence. This study provides an evidence-based logistic model that reduces LI-AN incidences and promotes the safe clinical use of linezolid.

Drug-Induced Peripheral Neuropathy: A Narrative Review

Background

Peripheral neuropathy is a painful condition deriving from many and varied etiologies. Certain medications have been implicated in the iatrogenic development of Drug Induced Peripheral Neuropathy (DIPN) and include chemotherapeutic agents, antimicrobials, cardiovascular drugs, psychotropic, anticonvulsants, among others. This review synthesizes current clinical concepts regarding the mechanism, common inciting medications, and treatment options for drug-induced peripheral neuropathy.

Methods

The authors undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. The most relevant and up to date research was included.

Results

Drug-induced peripheral neuropathy is a common and painful condition caused by many different and frequently prescribed medications. Most often, DIPN is seen in chemotherapeutic agents, antimicrobials, cardiovascular drugs, psychotropic, and anticonvulsant drugs. Certain drugs exhibit more consistent neuropathic side effects, such as the chemotherapeutic compounds, but others are more commonly prescribed by a larger proportion of providers, such as the statins. DIPN is more likely to occur in patients with concomitant risk factors such as preexisting neuropathy, diabetes, and associated genetically predisposing diseases. DIPN is often difficult to treat, however medications including duloxetine, and gabapentin are shown to reduce neuropathic pain. Advanced techniques of neuromodulation offer promise though further randomized and controlled studies are needed to confirm efficacy.

Conclusion

Awareness of the drugs covered in this review and their potential for adverse neuropathic effect is important for providers caring for patients who report new onset symptoms of pain, paresthesia, or weakness. Prevention of DIPN is especially important because treatment often proves challenging. While many pharmacologic therapies have demonstrated analgesic potential in the pain caused by DIPN, many patients remain refractive to treatment. More studies are needed to elucidate the effectiveness of interventional, neuromodulating therapies.

Long-Term Use of Tedizolid in Osteoarticular Infections: Benefits among Oxazolidinone Drugs

Background: To evaluate the efficacy and safety of long-term use of tedizolid in osteoarticular infections. Methods: Multicentric retrospective study (January 2017–March 2019) of osteoarticular infection cases treated with tedizolid. Failure: clinical worsening despite antibiotic treatment or the need of suppressive treatment. Results: Cases (n = 51; 59% women, mean age of 65 years) included osteoarthritis (n = 27, 53%), prosthetic joint infection (n = 17, 33.3%), and diabetic foot infections (n = 9, 18%); where, 59% were orthopedic device-related. Most frequent isolates were Staphylococcus spp. (65%, n = 47; S. aureus, 48%). Reasons for choosing tedizolid were potential drug-drug interaction (63%) and cytopenia (55%); median treatment duration was 29 days (interquartile range -IQR- 15–44), 24% received rifampicin (600 mg once daily) concomitantly, and adverse events were scarce (n = 3). Hemoglobin and platelet count stayed stable throughout treatment (from 108.6 g/L to 116.3 g/L, p = 0.079; and 240 × 10⁹/L to 239 × 10⁹/L, p = 0.942, respectively), also in the subgroup of cases with cytopenia. Among device-related infections, 33% were managed with implant retention. Median follow-up was 630 days and overall cure rate 83%; among failures (n = 8), 63% were device-related infections. Conclusions: Long-term use of tedizolid was effective, showing a better safety profile with less myelotoxicity and lower drug-drug interaction than linezolid. Confirmation of these advantages could make tedizolid the oxazolidinone of choice for most of osteoarticular infections.

Tolerance of Prolonged Oral Tedizolid for Prosthetic Joint Infections: Results of a Multicentre Prospective Study

Objectives: Data on clinical and biological tolerance of tedizolid (TZD) prolonged therapy are lacking. Methods: We conducted a prospective multicentre study including patients with prosthetic joint infections (PJIs) who were treated for at least 6 weeks but not more than 12 weeks. Results: Thirty-three adult patients of mean age 73.3 ± 10.5 years, with PJI including hip (n = 19), knee (n = 13) and shoulder (n = 1) were included. All patients were operated, with retention of the infected implants and one/two stage-replacements in 11 (33.3%) and 17/5 (51.5%/15.2%), respectively. Staphylococci and enterococci were the most prevalent bacteria identified. The mean duration of TZD therapy was 8.0 ± 3.27 weeks (6–12). TZD was associated with another antibiotic in 18 patients (54.5%), including rifampicin in 16 cases (48.5). Six patients (18.2%) had to stop TZD therapy prematurely because of intolerance which was potentially attributable to TZD (n = 2), early failure of PJI treatment (n = 2) or severe anaemia due to bleeding (n = 2). Regarding compliance with TZD therapy, no cases of two or more omissions of medication intake were recorded during the whole TZD treatment duration. Conclusions: These results suggest good compliance and a favourable safety profile of TZD, providing evidence of the potential benefit of the use of this agent for the antibiotic treatment of PJIs.

Linezolid Dosing in Patients With Liver Cirrhosis: Standard Dosing Risk Toxicity

BACKGROUND

Limited data regarding altered linezolid pharmacokinetics in patients with liver cirrhosis are available. The objective of this study was to evaluate the pharmacokinetics, efficacy and safety of linezolid in cirrhotic patients.

METHODS

A case-control 1:1 study of patients undergoing linezolid therapeutic drug monitoring was conducted between January 2015 and June 2017. Cases with liver cirrhosis were matched with controls by age, body weight, comorbidities, renal function, and intensive care unit (ICU) admission.

RESULTS

Fifty-two patients were included, 26 in each group. Patients with Child-Pugh Scores A, B, and C were 1 (3.8%), 13 (50.0%), and 12 (46.2%), respectively. Cases had higher median linezolid trough plasma concentrations than controls [20.6 (17.4) versus 2.7 (11.3); P < 0.001)] and more frequently achieved an optimal pharmacodynamic index [26 (100%) versus 16 (61.5%); P = 0.002]. In addition, potentially toxic concentrations and treatment discontinuation due to overexposure and hematological toxicity were also more frequently seen in cirrhotic patients. Overall clinical cure rate was high (67.4%), and in-hospital mortality was 28.8%. No differences in clinical outcomes were observed between both groups.

CONCLUSIONS

Linezolid showed a high clinical cure rate. Nevertheless, plasma concentrations and treatment discontinuation due to hematological toxicity were higher in cirrhotic patients. Liver cirrhosis may influence linezolid pharmacokinetics and question the use of standard doses. Therapeutic drug monitoring of linezolid would be valuable in these patients.

Clinical use of linezolid in periprosthetic joint infections - a systematic review

Introduction: The most common causative organism in periprosthetic joint infections (PJIs) is Gram-positive bacteria that are increasingly drug resistant. In these cases the use of linezolid may be warranted. However, there are conflicting reports regarding its role in antibiotic treatment of PJIs. The aim of this review is to gather and analyze clinical results and treatment details on linezolid in patients with PJIs. Methods: In August 2019, a comprehensive literature search using MEDLINE (Pubmed and Ovid) and Cochrane Library was performed. A total of 504 records were screened, and a total of 16 studies including 372 patients treated with linezolid for a PJI were included in this review based on the PRISMA criteria and after quality analysis using the MINOR score and Newcastle–Ottawa scale, as well as assessing level of evidence. Pooling analysis as well as descriptive analysis was performed. Results: Based on the results from the studies included, infection control was achieved in 80 % (range 30 %–100 %) of patients after a mean follow-up period of 25 (range 2–66) months. The mean duration of treatment was 58 d intravenous and orally at a median dose of 600 mg bis in die (b.i.d.) (range 400–900 b.i.d.). A combination therapy with rifampicin was used in 53 % of patients. MRSA (methicillin-resistant Staphylococcus aureus) infections were present in 29 % and resistant CoNS (coagulase-negative Staphylococcus) in 46 %. Adverse effects occurred in 33 % of cases, mostly anemia, thrombocytopenia and gastrointestinal complaints leading to treatment discontinuation in 9 %. However, great heterogeneity was found with respect to surgical treatment, diagnosis of infection and indication for linezolid. Discussion: Linezolid is an appropriate option for treatment of resistant Gram-positive organisms in PJIs. Most commonly 600 mg b.i.d. is used, and a combination with rifampicin appears feasible although one must consider individual increases in doses in these cases. However, adverse effects are common and there are limited data for long-term use and optimal antibiotic combinations or individual doses.

Safety and Tolerability of More than Six Days of Tedizolid Treatment

Tedizolid has demonstrated its efficacy and safety in clinical trials; however, data concerning its tolerability in long-term treatments are scarce. The aim of the study was to assess the indications and to describe the long-term safety profile of tedizolid. A multicentric retrospective study of patients who received tedizolid for more than 6 days was conducted. Adverse events (AEs) were identified from patients' medical records and laboratory data. The World Health Organization causality categories were used to discern AEs that were probably associated with tedizolid. Eighty-one patients, treated with tedizolid 200 mg once daily for a median (interquartile range [IQR]) duration of 28 (14 to 59) days, were included; 36 (44.4%) had previously received linezolid. The most common reasons for selecting tedizolid were to avoid linezolid potential toxicities or interactions (53.1%) or due to previous linezolid-related toxicities (27.2%). The most common indications were off-label, including prosthetic joint infections, osteomyelitis, and respiratory infections (77.8%). Overall, 9/81 patients (11.1%) experienced a probably associated AE. Two patients (2.5%) developed gastrointestinal disorders, 1 (1.2%) developed anemia, and 6 developed thrombocytopenia (7.4%) after a median (IQR) duration of treatment of 26.5 (17 to 58.5) days. Four (5%) patients discontinued tedizolid due to AEs. Among 23 patients with chronic renal failure (CRF), the rate of myelotoxicity was 17.4%, and only 8.7% had to stop tedizolid; 20 out of 22 with previous linezolid-associated toxicity had no AE. Long-term tedizolid treatments had good tolerance with rates of gastrointestinal AE and hematological toxicity lower than those reported with linezolid, particularly in patients with CRF and in those with a history of linezolid-associated toxicity.

Minocycline Combined with Vancomycin for the Treatment of Methicillin-Resistant Coagulase-Negative Staphylococcal Prosthetic Joint Infection Managed with Exchange Arthroplasty

Introduction: Treatment of methicillin-resistant (MR) staphylococcal prosthetic joint infections (PJIs) remains a matter of discussion, with vancomycin-rifampin combination therapy being the preferred treatment for DAIR and one-stage exchange arthroplasty strategies. This study analyzes the outcomes of patients with chronic methicillin-resistant coagulase-negative staphylococcal PJIs treated with vancomycin-minocycline combination therapy.

Methods: This prospective, single center cohort study included all chronic MR coagulase-negative staphylococcal PJIs (01/2004-12/2014) treated with exchange arthroplasty and at least 4 weeks of minocycline-vancomycin. The following endpoints were considered: reinfection including relapse (same microorganism) and a new infection (different microorganism) and PJI-related deaths. Their outcomes were compared with PJIs treated with rifampin-vancomycin during the same period.

Results: Thirty-four patients (median age, 69 years) with 22 hip and 12 knee arthroplasty infections were included. Sixteen (47%) had previously been managed in another center. Median vancomycin MIC of strains was 3 mg/L. Nineteen underwent one-stage, 15 two-stage exchange arthroplasty. After a median [IQR] follow-up of 43 [26-68] months, 2 patients relapsed and 6 developed a new PJI. Compared to 36 rifampin-vancomycin treated PJIs, relapse- or reinfection-free survival rates didn't differ, but more new infections developed in the minocycline group (6 vs 3; P 0.3).

Conclusions: Minocycline-vancomycin combination therapy for chronic MR coagulase-negative staphylococcal PJIs seems to be an interesting therapeutic alternative.

Effect of coadministration of rifampicin on the pharmacokinetics of linezolid: clinical and animal studies

Background

Combination therapy of linezolid (LZD) and rifampicin (RFP) may be more effective than monotherapy for treating gram-positive bacterial infections, but several studies have suggested that RFP decreases LZD exposures, thereby increasing the risk of therapeutic failure and emergence of LZD-resistant strains. However, the mechanism of the drug-drug interaction between LZD and RFP is unknown.

Methods

We conducted a prospective, open-label, uncontrolled clinical study in Japanese patients receiving LZD and RFP to evaluate the effect of coadministered RFP on the concentration of LZD. In animal study in rats, the influence of coadministered RFP on the pharmacokinetics of LZD administered intravenously or orally was examined. Intestinal permeability was investigated with an Ussing chamber to assess whether coadministered RFP alters the absorption process of LZD in the intestine.

Results

Our clinical study indicated that multiple doses of RFP reduced the dose-normalized trough concentration of LZD at the first assessment day by an average of 65%. In an animal study, we found that multiple doses of RFP significantly decreased the area under the concentration-time curve, the maximum concentration and the bioavailability of orally administered LZD by 48%, 54% and 48%, respectively. In contrast, the pharmacokinetics of intravenously administered LZD was unaffected by the RFP pretreatment. However, investigation of the intestinal permeability of LZD revealed no difference in absorptive or secretory transport of LZD in the upper, middle and lower intestinal tissues between RFP-pretreated and control rats, even though RFP induced gene expression of multidrug resistance protein 1a and multidrug resistance-associated protein 2.

Conclusions

Therapeutic drug monitoring may be important for avoiding subtherapeutic levels of LZD in the combination therapy. The drug-drug interaction between LZD and RFP may occur only after oral administration of LZD, but is not due to any change of intestinal permeability of LZD.

Trial registration

UMIN, UMIN000004322. Registered 4 October 2010.

Evaluation of linezolid or trimethoprim/sulfamethoxazole in combination with rifampicin as alternative oral treatments based on an in vitro pharmacodynamic model of staphylococcal biofilm

Combinations of linezolid (LZD) or trimethoprim/sulfamethoxazole (SXT) plus rifampicin (RIF) are alternative oral treatments for staphylococcal prosthetic joint infections (PJIs) when fluoroquinolones are not possible to use, but there is limited evidence regarding their activity. This study evaluated the efficacy of LZD and SXT, alone and in combination with RIF, against Staphylococcus aureus in an in vitro pharmacokinetic/pharmacodynamic biofilm model. Using the CDC Biofilm Reactor^® system, simulated regimens of LZD (600 mg every 12 h), SXT (160/800 mg every 8 h) and levofloxacin (LVX) (750 mg/day), alone and in combination with RIF (600 mg/day), were evaluated against one methicillin-susceptible S. aureus (MSSA) and one methicillin-resistant S. aureus (MRSA) strain. Antibiotic efficacy was evaluated by the decrease in planktonic bacterial counts from medium and biofilm-embedded bacteria from coupons over 56 h. Resistant strains were screened. In both strains, SXT alone was ineffective and LZD presented low activity, but no resistance emerged. Combinations with RIF significantly increased the antibiofilm efficacy against MSSA (Δlog CFU/mL 56h-0h: SXT + RIF, -2.9 and LZD + RIF, -3.1), but RIF-resistant strains appeared with SXT + RIF. Against MRSA, LZD + RIF (-3.1) protected against the emergence of resistance and was more effective than SXT + RIF (-0.6; P <0.05), in which RIF-resistant strains were again detected. LVX + RIF confirmed its high efficacy against biofilm-embedded bacteria, this being the most effective therapy (-5.1 against MSSA). The emergence of RIF-resistant strains with SXT + RIF poses serious concerns for its use in clinical practice. Interestingly, LZD + RIF appears to be an appropriate alternative for PJI caused by LVX-resistant S. aureus.

Multidrug-Resistant Organisms in the Setting of Periprosthetic Joint Infection-Diagnosis, Prevention, and Treatment

BACKGROUND

Periprosthetic joint infection (PJI) is a rare yet challenging problem in total hip and knee arthroplasties. The management of PJI remains difficult primarily due to the evolution of resistance by the infecting organisms.

METHODS

This review profiles acquired mechanisms of bacterial resistance and summarizes established and emerging techniques in PJI diagnosis, prevention, and treatment.

RESULTS

New techniques in PJI diagnosis and prevention continue to be explored. Antibiotics combined with 1 or 2-stage revision are associated with the higher success rates and remain the mainstay of treatment.

CONCLUSION

With higher prevalence of antibiotic-resistant organisms, novel antibiotic implant and wound care materials, improved methods for organism identification, and well-defined organism-specific treatment algorithms are needed to optimize outcomes of PJI.

Safety of long-term use of linezolid: results of an open-label study

Objective

The objective of this study was to assess the long-term safety of linezolid in patients with chronic infections requiring treatment for ≥6 weeks. Enhanced monitoring for optic neuropathy was included to characterize the early development of this side effect and to identify ophthalmologic tests that might be valuable in early detection of this event.

Methods

This was a multicenter, open-label, pilot study of patients aged ≥18 years on long-term linezolid therapy. Matched control patients were included for baseline assessment comparison. Patients were assessed at study entry, monthly while on treatment, at the end of treatment, and 30 days following the last dose. Aggregate ocular safety data were reviewed. Response to treatment was reported.

Results

The study was terminated owing to slow enrollment. Twenty-four patients received linezolid; nine patients were included as matched controls. Linezolid was prescribed for a median of 80.5 days (range, 50–254 days). In patients with a reported clinical outcome, the majority were considered improved or cured. Common treatment-related adverse events (AEs) included anemia, peripheral neuropathy, polyneuropathy, vomiting, and asthenia, and were consistent with the known safety profile. Most AEs resolved or stabilized with discontinuation of treatment. Results of ophthalmologic tests in the one case adjudicated as probable linezolid-associated optic neuropathy revealed abnormal color vision, characteristic changes in the optic disk, and central scotomas in each eye.

Conclusion

In our small population, linezolid was generally well tolerated and AEs were consistent with the known safety profile. Extensive ophthalmologic testing of all 24 linezolid-treated patients identified one case adjudicated as probable, linezolid-associated optic neuropathy.

Clinical experience with linezolid for the treatment of orthopaedic implant infections

Gram-positive cocci are commonly isolated in orthopaedic implant infections and their resistance to β-lactams and fluoroquinolones is increasing. The high oral bioavailability of linezolid makes it an attractive oral alternative to glycopeptides and its use has increased in the last decade. To evaluate experience with linezolid in orthopaedic implant infections a systematic review of the literature available in English was undertaken. Only those articles describing series of ≥10 patients with acute or chronic orthopaedic implant infections treated with linezolid and with a clear definition of diagnosis and outcome were selected. A total of 293 patients (79.9% had prosthetic joint infections) were analysed in the 10 articles included. The overall remission rate with at least 3 months of follow-up was 79.9%, depending on whether the implant was removed or not (94% versus 69.9%). The addition of rifampicin was described in only two articles and no significant difference was observed. Adverse events were frequent during prolonged administration of linezolid (34.3%), requiring treatment discontinuation in 12.8%. The most common event was anaemia (13.4%) followed by gastrointestinal symptoms (11.1%). In conclusion, linezolid seems a good oral treatment alternative for orthopaedic implant infections due to Gram-positive cocci resistant to β-lactams and fluoroquinolones. However, close monitoring of adverse events is required.

A Retrospective Review of the Clinical Experience of Linezolid with or Without Rifampicin in Prosthetic Joint Infections Treated with Debridement and Implant Retention

Introduction

Debridement and prosthesis retention, combined with a prolonged antibiotic regimen including rifampicin, is an accepted therapeutic approach when the duration of symptoms is less than 4 weeks and there are no radiological signs of loosening. The outcome of patients managed with this strategy has been previously assessed in several articles with success rates of 60–90%. This study aims to review the clinical experience with linezolid in 3 different hospitals from Spain and France in patients with prosthetic joint infection (PJI) managed with debridement, retention of the implant and treated with linezolid with or without rifampicin.

Methods

Patients with an acute PJI who underwent open debridement with implant retention treated with linezolid for more than 7 days in 3 hospitals from Barcelona, Tours and Lille between 2005 and 2011 were retrospectively reviewed. Relevant information about demographics, co-morbidity, type of implant, surgical treatment, microorganism isolated, antimicrobial therapy, adverse events (AEs) and outcomes were recorded from patients.

Results

A total of 39 patients were retrospectively reviewed. The mean age (SD) was 70.5 (8.8) years and 9 patients had diabetes mellitus (23%). There were 25 (64%) knee prostheses, 13 (33%) hips and 1 shoulder (3%). The median interquartile range (IQR) days from arthroplasty to infection diagnosis was 17 (19–48) and 33 (85%) cases were diagnosed within the first 60 days. The median (IQR) duration of antibiotic treatment was 70.5 (34–96) days and the median (IQR) number of days on linezolid treatment was 44.5 (30–81). AEs were observed in 15 patients (38%), with gastrointestinal complaints in 8 cases and anemia in 5 being the most frequent. After a median (IQR) follow-up of 2.5 (1.8–3.6) years, there were 11 failures (28%) (8 relapses and 3 new infections). The failure rate was higher in the rifampicin group (36% vs. 18%) mainly due to a higher relapse rate (27% vs. 12%) although differences were not statistically significant.

Conclusion

Management of acute PJIs with debridement and retention of the implant linezolid, with or without rifampicin, is associated with a high remission rate and it is an alternative treatment for infections due to fluoroquinolone and/or rifampicin-resistant staphylococci.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0032-z) contains supplementary material, which is available to authorized users.

Role and antimicrobial resistance of staphylococci involved in prosthetic joint infections

PURPOSE

Staphylococci are responsible for approximately half of all prosthetic joint infections (PJIs) and they are often multi-drug resistant. The main purpose of this study was to evaluate the incidence of PJIs caused by staphylococci in our hospital from March 2010 to February 2012, with particular reference to antibiotic resistance in relation to their classification as contaminant or infecting isolates.

METHODS

We analyzed samples recovered from 124 patients: most of them were male (55.8%) and the mean age was 66 ± 14 years. Prostheses derived from hip (54.8%) or knee (45.2%) replacement and they were processed by sonication. Isolates were identified using conventional biochemical methodologies. Antimicrobial susceptibility testing was carried out using the disk diffusion method as described by the European Committee on Antimicrobial Susceptibility Testing.

RESULTS

A total of 135 staphylococci were isolated: the prevalent species was Staphylococcus aureus, but, on the whole, coagulase-negative staphylococci represented 57% of cases. Fifty-one isolates were recovered from a single sample and were therefore defined as contaminant. Linezolid and glycopeptides showed excellent activity versus all the tested isolates, while penicillin, levofloxacin, and erythromycin offered reduced activity against staphylococci. Interestingly, high resistance rates were observed for coagulase-negative staphylococci other than S. epidermidis classified as contaminant strains.

CONCLUSIONS

We observed a remarkable spread of coagulase-negative staphylococci as causative agents of PJIs; but most of them were classified as contaminants. However, because of their low susceptibility to the antibiotics tested, further studies are necessary to evaluate their role as pathogens or as true contaminants.

Current pharmacotherapy options for osteomyelitis: convergences, divergences and lessons to be drawn

INTRODUCTION

Antibiotic therapy of osteomyelitis is complex and requires a multidisciplinary approach including surgeons and infectious diseases specialists. However, it suffers from a lack of high-quality clinical studies indicating the superiority of one type of therapy over another. Knowing the antibiotics and their main characteristics is important to guide the choice of treatment for patients with osteomyelitis.

AREAS COVERED

The aim of the present article is to review the systemic curative antibiotic therapy of osteomyelitis in adults with a focus on new agents. Diabetic foot osteomyelitis will be briefly discussed separately. A literature search of the PubMed database using the term 'osteomyelitis' alone and in combination with 'hematogenous', 'vertebral', 'biofilm', 'diabetic foot', 'trauma', 'antibiotic' 'daptomycin', 'telavancin', 'tigecycline', 'linezolid', 'ertapenem', 'ceftobiprole' and 'ceftaroline' was carried out.

EXPERT OPINION

Antibiotic treatment of acute and chronic osteomyelitis should be considered as two distinct entities with regard to the choice of the most appropriate antibiotics and the need for surgery. Among the most recently available antibiotics, ertapenem and daptomycin are promising agents for the treatment of osteomyelitis due to resistant bacteria.

Optimizing combination rifampin therapy for staphylococcal osteoarticular infections

Staphylococcus spp. causes more than half of all osteoarticular infections of native structures or implanted material. The ability of Staphylococcus spp. to persist within infected bone tissue and to produce a bacterial biofilm, most notably in infections of implanted material, can lead to treatment failures and microbiological relapses. Rifampin is a cornerstone of the treatment of staphylococcal osteoarticular infections, particularly those of implanted material. Rifampin is a bactericidal antibiotic that diffuses very well within bone tissue and bacterial biofilms. The mechanism of action is inhibition of bacterial DNA transcription to mRNA independently from bacterial division, which results in activity against even dormant Staphylococcus spp. organisms. However, the high risk of emergence of rifampin-resistant mutants requires the concomitant administration of another antibiotic. Several antibiotics are recommended in the French guidelines issued by the French-Speaking Society for Infectious Diseases (Société de Pathologie Infectieuse de Langue Française [SPILF]). Here, we discuss the results from in vitro, animal, and clinical studies that explain the advantages and drawbacks of each antibiotic used with rifampin to treat osteoarticular infections due to Staphylococcus spp.

An evidence-based review of linezolid for the treatment of methicillin-resistant Staphylococcus aureus (MRSA): place in therapy

Methicillin-resistant Staphylococcus aureus (MRSA), including community-associated and hospital-associated strains, is a major cause of human morbidity and mortality. Treatment options have become limited due to the emergence of MRSA strains with decreased sensitivity to vancomycin, which has long been the first-line therapy for serious infections. This has prompted the search for novel antibiotics that are efficacious against MRSA. Linezolid, an oxazolidinone class of antibiotic, was approved by the Food and Drug Administration in 2000 for treatment of MRSA infections. Since then, there have been a multitude of clinical trials and research studies evaluating the effectiveness of linezolid against serious infections, including pneumonia (both community- and hospital-acquired), skin and soft-tissue infections such as diabetic foot ulcers, endocarditis, osteomyelitis, prosthetic devices, and others. The primary aim of this review is to provide an up-to-date evaluation of the clinical evidence for using linezolid to treat MRSA infections, with a focus on recently published studies, including those on nosocomial pneumonia. Other objectives are to analyze the cost-effectiveness of linezolid compared to other agents, and to review the pharmokinetics and pharmacodynamics of linezolid, emphasizing the most current concepts.

Long-term treatment with linezolid in a patient with osteomyelitis undergoing hemodialysis

Anemia and/or thrombocytopenia are the most relevant adverse effects of linezolid treatment. We report the case of a patient under hemodialysis who developed osteomyelitis involving the amputation stump of the left limb due to a vancomycin-resistant and teicoplanin-resistant Enterococcus faecium successfully treated with linezolid for 6 months. Close monitorization of the patient probably contributed to maintenance of treatment with linezolid despite hematological alterations observed, which could be attributed to either the underlying patient's clinical condition or antimicrobial treatment.

Therapeutic drug monitoring may improve safety outcomes of long-term treatment with linezolid in adult patients

OBJECTIVES

Prolonged treatment with linezolid may cause toxicity. The purpose of this study was to define pharmacodynamic thresholds for improving safety outcomes of linezolid.

METHODS

We performed a retrospective study of patients who had trough (C(min)) and peak (C(max)) plasma levels measured during prolonged linezolid treatment. Dosage adjustments were performed when C(min) ≥10 mg/L and/or AUC₂₄ ≥400 mg/L · h. Patients were divided into two subgroups according to the absence or presence of co-treatment with rifampicin (the linezolid group and the linezolid + rifampicin group, respectively). Data on demographic characteristics, disease, microbiology and haematochemical parameters were collected and outcomes in relation to drug exposure were compared between groups.

RESULTS

A total of 45 patients were included. Dosage adjustments were needed in 40% versus 0% of patients in the linezolid group (n = 35) versus the linezolid + rifampicin group (n = 10), respectively. Patients in the linezolid group had either significantly higher C(min) [3.71 mg/L (1.43-6.38) versus 1.37 mg/L (0.67-2.55), P < 0.001] or AUC₂₄ [212.77 mg/L · h (166.67-278.42) versus 123.33 mg/L · h (97.36-187.94), P < 0.001]. Thrombocytopenia appeared in 51.4% versus 0% of cases in the linezolid group versus the linezolid + rifampicin group, respectively. In 33.3% of those patients who were experiencing thrombocytopenia, therapeutic drug monitoring (TDM)-guided dosage reductions allowed recovery from toxicity and prosecution of therapy with good outcome. A logistic regression model for thrombocytopenia estimated a probability of 50% in the presence of C(min) of 6.53 mg/L and/or of AUC₂₄ of 280.74 mg/L · h.

CONCLUSIONS

Maintenance over time of C(min) between 2 and 7 mg/L and/or of AUC₂₄ between 160 and 300 mg/L · h may be helpful in improving safety outcomes while retaining appropriate efficacy in adult patients receiving prolonged linezolid treatment.

Factors governing the healing of Staphylococcus aureus infections following hip and knee prosthesis implantation: a retrospective study of 95 patients

INTRODUCTION

The prognostic factors for total hip arthroplasty (THA) and total knee arthroplasty (TKA) Staphylococcus aureus prosthetic joint infections are poorly known, notably because of the heterogeneous management in terms of both antibiotic administration and adopted surgical strategy. Uniform treatment regimens would make it easier to define the outcome of these S. aureus infections.

PATIENTS AND METHODS

Between 2001 and 2006, 95 patients with a S. aureus joint infection after THA or TKA were treated, strictly following a standardized protocol according to the recommendations of Zimmerli et al. The patients' mean age was 65.7 years, 71 with THA and 28 with TKA (four patients had two infected joints). These 95 patients presented 120 infectious episodes, all of whom had surgical treatment: 53 lavages (44.1%), 17 one-stage prosthesis revisions (14.2%), 29 two-stage prosthesis revisions (24.2%), and 21 prostheses removed (17.5%). On the intraoperative samples taken, methicillin-sensitive S. aureus (MSSA) was isolated in 88 patients (73.3%) and methicillin-resistant S. aureus (MRSA) in 18 patients (15%); finally 14 patients were included because of the positive results of preoperative samples taken. Twenty-seven infections (22.5%) were multibacterial, including at least S. aureus and 93 were single S. aureus bacteria. Success was defined at a minimum 12 months of follow-up by the association of the following parameters: normal erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) results, noninflammatory scar with no fistula, no surgical revision, and no antibiotic treatment.

RESULTS

At a mean follow-up of 38±24.9 months, 81 of the 120 infectious episodes were resolved (67.5%) and 77 of the 95 patients were healed (81%). Six parameters significantly influenced the healing of the infection: initial cementless fixation, THA, preoperative knowledge of the bacterium, immediate postoperative antibiotic therapy adapted to the microbiological data, changing the prosthesis, and monobacterial infection. Only the latter two were independent, with an odds ratio of 5 (1.6-14.9) and 2.9 (1.1-7.7) respectively. However, resistance to methicillin did not appear to be a factor of failure.

DISCUSSION

Management of prosthetic S. aureus infections according to a uniform protocol in a specialized medical center healed the infection in 81% of the patients. Treatment improvement requires knowledge of the bacterium, adaptation of immediate probabilistic antibiotic therapy, and preference for changing the prosthesis over simple lavage.

Linezolid pharmacokinetics and pharmacodynamics in clinical treatment

Linezolid has been widely used in the treatment of Gram-positive infections for more than a decade. It is unique amongst antibiotics active against most multiply-resistant Gram-positive bacteria in that there is an oral preparation with 100% bioavailability and an extensive volume of distribution. This review examines pharmacokinetic data relating to linezolid use in different patient groups (obesity, enteral feeding, renal failure, neonates, and paediatrics) and in different clinical conditions (sepsis syndrome, skin and soft tissue infection, diabetic foot infection, pneumonia, bone and joint infection, infection of the central nervous system, eye infection, and neutropenic sepsis).

Linezolid plus rifampin as a salvage therapy in prosthetic joint infections treated without removing the implant

The aim of this study is to describe our experience with linezolid plus rifampin as a salvage therapy in prosthetic joint infections (PJIs) when other antibiotic regimens failed or were not tolerated. A total of 161 patients with a documented prosthetic joint infection were diagnosed with a PJI and prospectively followed up from January 2000 to April 2007. Clinical characteristics, inflammatory markers, microbiological and radiological data, and antibiotic treatment were recorded. After a 2-year follow-up, patients were classified as cured when the prosthesis was not removed, symptoms of infection disappeared, and inflammatory parameters were within the normal range. Any other outcome was considered a failure. The mean age of the entire cohort (n = 161) was 67 years. Ninety-five episodes were on a knee prosthesis (59%), and 66 were on a hip prosthesis (41%). A total of 49 patients received linezolid plus rifampin: 45 due to failure of the previous antibiotic regimen and 4 due to an adverse event associated with the prior antibiotics. In no case was the implant removed. The mean (standard deviation) duration of treatment was 80.2 (29.7) days. The success rate after 24 months of follow-up was 69.4% (34/49 patients). Three patients developed thrombocytopenia and 3 developed anemia; however, it was not necessary to stop linezolid. Linezolid plus rifampin is an alternative salvage therapy when the implant is not removed.