Clinical experience with linezolid for the treatment of orthopaedic implant infections

Linezolid Toxicity: A Clinical Case Report

Linezolid plays a clinically important role; however, it is responsible for severe pharmacological interactions and side effects, such as myelosuppression, serotonin syndrome, and lactic acidosis. We report a case of an 80-year-old man treated with venlafaxine for depression. He was admitted with a right femur fracture and submitted to surgical intervention, complicated by local infection. In collected pus was identified multiple microorganisms including Enterococcus faecium resistant to vancomycin. The therapeutic was adjusted to linezolid. On the 36th day of treatment, he developed hypertension, poor peripheral perfusion, and generalized tremor. He was disoriented, with marbled skin, myoclonus, and sinus tachycardia; and apyretic, with no signs of respiratory distress or joint/surgical wound inflammatory signs. Blood tests showed hyperlacticemia and discrete elevation of C-reactive protein but in a decrescent trend, with no other relevant alterations. The diagnosis of lactic acidosis and probable serotonin syndrome secondary to linezolid was made, supported by improvement after the drug suspension.

Population pharmacokinetics of antibacterial agents in the older population: a literature review

INTRODUCTION

Older individuals face an elevated risk of developing bacterial infections. The optimal use of antibacterial agents in this population is challenging because of age-related physiological alterations, changes in pharmacokinetics (PK) and pharmacodynamics (PD), and the presence of multiple underlying diseases. Therefore, population pharmacokinetics (PPK) studies are of great importance for optimizing individual treatments and prompt identification of potential risk factors.

AREA COVERED

Our search involved keywords such as 'elderly,' 'old people,' and 'geriatric,' combined with 'population pharmacokinetics' and 'antibacterial agents.' This comprehensive search yielded 11 categories encompassing 28 antibacterial drugs, including vancomycin, ceftriaxone, meropenem, and linezolid. Out of 127 studies identified, 26 (20.5%) were associated with vancomycin, 14 (11%) with meropenem, and 14 (11%) with piperacillin. Other antibacterial agents were administered less frequently.

EXPERT OPINION

PPK studies are invaluable for elucidating the characteristics and relevant factors affecting the PK of antibacterial agents in the older population. Further research is warranted to develop and validate PPK models for antibacterial agents in this vulnerable population.

Antibiotic therapy in reconstructive surgery of deep sternal wound infections

BACKGROUND

The choice of antibiotics and length of administration in the treatment of deep sternal wound infections (DSWI) is unclear. The reason for this is the lack of studies and local differences in resistance. An increase in resistance can be observed in gram-positive cocci, which are the most frequently detected in deep sternal infections. The duration of administration is often 2- 6 weeks or longer, although the benefit of prolonged antibiotic administration has not been confirmed by studies. We evaluated the antibiotic treatment during surgical treatment, consisting of surgical wound debridement and plastic chest reconstruction.

METHODS

Retrospective analysis of patients (n = 260) who underwent reconstructive surgery in the Department of Plastic Surgery at Leipzig University Hospital from 01.05.2012 - 31.12.2020. The duration of intake, results of microbiological swabs and resistance were investigated.

RESULTS

At the time of discharge, closed wound conditions were noted in 177 of 260 cases (68.1%). The largest proportion of patients (n = 238) was treated with a latissimus dorsi flap (91.5%).Antibiotic treatment was conducted in 206 of 260 cases (79.2%). The mean duration of antibiotic administration was 21.4 days (±17.6). Prolonged treatment over 14 days did not alter outcome (p = 0.226), in contrast, the number of multidrug resistances (p < 0.001). There was no prove of resistance against linezolid which is effective against the most common found infectious agents Staphylococcus epidermidis (n = 93; 24.0 %) & Staphylococcus aureus (n = 47; 12.1 %).

CONCLUSION

There is no evidence of benefit from antibiotic therapy over 14 days, whereas multidrug resistance increases with prolonged antibiotic use. In the absence of infectious agents or clinical signs of inflammation, surgical treatment without additional antibiotic treatment is effective.Linezolid is a suitable antibiotic in the treatment of gram-positive infections which are the most frequent in DSWI.

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.

A cost minimisation analysis comparing oral linezolid and intravenous daptomycin administered via an outpatient parenteral antibiotic therapy programme in patients requiring prolonged antibiotic courses

This study is an economic analysis seeking to examine cost savings that may be accrued from usage of oral linezolid in place of OPAT IV daptomycin in patients requiring prolonged courses of IV or highly bioavailable oral antibiotic therapy. In order to do so we conducted a literature review to establish the scenarios in which the agents could be considered equivalent. We then, using a decision-tree model, conducted a cost analysis to establish differences in cost between the approaches. Under the model base-case, the total cost of treatment with OPAT daptomycin was €3,496.84 and the total cost of treatment with oral linezolid was €772.01. Therefore the oral linezolid strategy would be projected to save the Irish health service €2,724.83 per patient. These results were robust to one-way deterministic sensitivity analyses and probabilistic sensitivity analysis. Our study suggests that significant savings could be safely accrued in the management of these patients.

Genomic Analysis of a Linezolid-Resistant Staphylococcus capitis Causing Bacteremia: Report from a University Hospital in Central Italy

Although coagulase negative staphylococci are rarely associated with complicated diseases, in some cases they cause life-threatening infections. Here we described a clinical case of a bacteremia due to a methicillin- and linezolid-resistant Staphylococcus capitis in a patient previously treated with linezolid. Whole genome sequencing revealed the common mutation G2576T in all rDNA 23S alleles and several acquired resistance genes. Moreover, the isolate was epidemiologically distant from the NRCS-A clade, usually responsible for nosocomial infections in neonatal intensive care units. Our findings further confirm the ability of minor staphylococci to acquire antibiotic resistances and challenge the treatment of these infections.

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.

Pharmacokinetic and pharmacodynamic considerations for optimizing antimicrobial therapy used to treat bone and joint infections: an evidence-based algorithmic approach

INTRODUCTION

Bone and joint infections (BJIs) are a major health concern causing remarkable morbidity and mortality. However, which antimicrobial treatment could be the best according to specific clinical scenarios and/or to the pharmacokinetic/pharmacodynamic (PK/PD) features remains an unmet clinical need. This multidisciplinary opinion article aims to develop evidence-based algorithms for empirical and targeted antibiotic therapy of patients affected by BJIs.

AREAS COVERED

A multidisciplinary team of four experts had several rounds of assessment for developing algorithms devoted to empirical and targeted antimicrobial therapy of BJIs. A literature search was performed on PubMed-MEDLINE (until April 2023) to provide evidence for supporting therapeutic choices. Four different clinical scenarios were structured according to specific infection types (i.e. vertebral osteomyelitis, prosthetic joint infections, infected non-unions and other chronic osteomyelitis, and infectious arthritis), need or not of surgical intervention or revision, isolation or not of clinically relevant bacterial pathogens from blood and/or tissue cultures, and PK/PD features of antibiotics.

EXPERT OPINION

The proposed therapeutic algorithms were based on a multifaceted approach considering the peculiar features of each antibiotic (spectrum of activity, PK/PD properties, bone penetration rate, and anti-biofilm activity), and could be hopefully helpful in improving clinical outcome of BJIs.

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.

Identifying and Targeting Prediction of the PI3K-AKT Signaling Pathway in Drug-Induced Thrombocytopenia in Infected Patients Receiving Linezolid Therapy: A Network Pharmacology-Based Analysis

The pharmacological mechanisms underlying the adverse effects of linezolid on thrombocytopenia have not been conclusively determined. This network pharmacology study aimed at investigating the potential pharmacological mechanisms of linezolid-induced adverse reactions in thrombocytopenia. In this study, target genes for linezolid and thrombocytopenia were compared and analyzed. Overlapping thrombocytopenia-associated targets and predicted targets of linezolid were imported to establish protein-protein interaction networks. Gene Ontology and the Kyoto Encyclopedia of Genes and Genome pathway enrichment analyses were performed to determine the enriched biological terms and pathways. The mechanisms involved in linezolid-induced thrombocytopenia were established to be associated with various biological processes, including T cell activation, peptidyl serine modification, and peptidyl serine phosphorylation. The top five relevant protein targets were obtained, including ALB, AKT1, EGFR, IL6, and MTOR. Enrichment analysis showed that the targets of linezolid were positively correlated with T cell activation responses. The mechanism of action of linezolid was positively correlated with the PI3K-AKT signaling pathway and negatively correlated with the Ras signaling pathway. We identified the important protein targets and signaling pathways involved in linezolid-induced thrombocytopenia in anti-infection therapy, providing new information for subsequent studies on the pathogenesis of drug-induced thrombocytopenia and potential therapeutic strategies for rational use of linezolid in clinical settings.

Factors associated with late microbiological documentation of prosthetic joint infection

Purpose: To describe the number of prosthetic joint infections (PJIs) with late documentation and to identify associated factors. Methods: Bacterial PJIs with surgical management between November 2015 and November 2019 in a French center were analyzed. Results of short (72 h) and late culture (at 14 days) were analyzed. Results: A total of 160 PJIs were reported with 215 bacteria. Twenty-nine patients had late documentation (18.1%). The bacteria most involved were coagulase-negative staphylococci and Cutibacterium spp. (60%). In multivariate analysis, late chronic PJI (odds ratio = 2.47) and antibiotic therapy before surgery (odds ratio = 3.13) were associated with late-documented infection. Conclusion: A better knowledge of the factors associated with late-documented infections is essential in order to simplify antibiotic treatment at the appropriate time.

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.

Proactive therapeutic drug monitoring (TDM) may be helpful in managing long-term treatment with linezolid safely: findings from a monocentric, prospective, open-label, interventional study

BACKGROUND

Thrombocytopenia may be a dose-dependent adverse effect of linezolid therapy.

OBJECTIVES

To assess whether proactive therapeutic drug monitoring (TDM) could be helpful in preventing and/or in recovering from the occurrence of linezolid-induced thrombocytopenia during long-term treatment.

METHODS

This was a monocentric, prospective, open-label, interventional study conducted between June 2015 and December 2017 among adult patients receiving >10 days of linezolid therapy and undergoing proactive TDM (desired trough level 2-8 mg/L) and platelet count assessment at day 3-5 and then once weekly up to the end of treatment.

RESULTS

Sixty-one patients were included. Twenty-eight (45.9%) always had desired trough level (group A) and 33 (54.1%) experienced linezolid overexposure (group B) [29/33 transiently (subgroup B1) and 4/33 persistently (subgroup B2)]. No patient experienced linezolid underexposure. Median duration of treatment for the different groups ranged between 19 and 54 days. Thrombocytopenia occurred overall in 14.8% of cases (9/61). The incidence rate of thrombocytopenia was significantly lower (P=0.012) in both group A (10.7%; 3/28) and subgroup B1 (10.3%; 3/29) than in subgroup B2 (75.0%; 3/4). Thrombocytopenic patients belonging to both group A and group B1 recovered from thrombocytopenia without the need for discontinuing therapy. Multivariate linear regression analysis revealed that thrombocytopenia was independently associated with baseline platelet count and with median linezolid trough concentrations.

CONCLUSIONS

Proactive TDM of linezolid may be beneficial either in preventing or in recovering from dose-dependent thrombocytopenia, even when treatment lasts for more than 28 days. Larger prospective studies are warranted to confirm our findings.

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.

Linezolid versus daptomycin treatment for periprosthetic joint infections: a retrospective cohort study

BACKGROUND

Linezolid (LZD) and daptomycin (DAP) are predominantly used to target gram-positive pathogens; however, treatment effectiveness and adverse reactions for periprosthetic joint infections (PJIs) remain unknown. The aim of this study was to compare the effectiveness and adverse reactions of LZD and DAP for PJIs.

METHODS

This study retrospectively evaluated 82 patients between June 2009 and December 2017, to compare the effectiveness of LZD (group L, n = 39) and DAP (group D, n = 43) for treatment of PJIs harboring gram-positive microorganisms. Surgical options used with LZD or DAP therapy included implant retention, implant removal, and a shift to another appropriate antibiotic. Infection control was defined as not requiring implant removal after the final treatment.

RESULTS

Gram-positive pathogens were isolated from 72% of group L and 70% of group D patients, respectively. Whole infection control rates against gram-positive pathogens in groups L and D were 79% and 77%, respectively. Furthermore, infection control rates were 94% and 58% in group L and 75% and 80% in group D, without and with implant removal, respectively. Significantly higher clinical success rates and lower adverse event rates were observed in group D, including higher red blood cell and platelet counts and lower C-reactive protein (CRP) levels.

CONCLUSIONS

Although the effectiveness of LZD and DAP was equivalent in terms of infection control rates for refractory PJIs with gram-positive pathogens, DAP therapy significantly decreased CRP levels and caused fewer adverse events than LZD treatment.

New Gene Responsible for Resistance of Clinical Corynebacteria to Macrolide, Lincosamide and Streptogramin B

The subject of the study was phenotypic marking of the antibiotic susceptibility and MLS_B resistance mechanism in Corynebacterium spp. isolated from human skin (18 isolates) and from clinical materials (19 isolates). The strains were tested for the presence of the erm(A), erm(B), erm(C), erm(X), lnu(A), msr(A), msr(B) and mph(C) genes. Clinical isolates showed wide resistance to antibiotics. In 89% clinical isolates and 72% skin microbiota a constitutive type of MLS_B resistance was found. In 12 clinical isolates the erm(C) gene was detected-eight of which had erm(X) as well as erm(C), two harboured erm(X), erm(C) and erm(A) and two demonstrated only erm(C).

Bacteriological relevance of linezolid vs. vancomycin in postoperative empirical treatment of osteoarticular infections: a retrospective single-center study

BACKGROUND

In 2015, our center replaced vancomycin with linezolid for the postoperative empirical treatment of osteoarticular infections (OAI).

OBJECTIVES

To assess the bacteriological relevance of linezolid for orthopedic postoperative probabilistic antibiotic therapy.

METHODS

Analysis of an observational cohort of patients empirically treated with a combination of linezolid and piperacillin/tazobactam during the immediate postoperative stage for an OAI between July 1^st 2015 and July 1^st 2016, in a French reference center.

RESULTS

Seventy-seven of 126 patients who received a probabilistic postoperative combination of linezolid with piperacillin/tazobactam had microbiological proof of infection. Sixty-six of 77 OAI involved material, including an osteosynthesis in 45 cases (68%) and prosthesis in 21 cases (32%). Infection was due to Gram-positive bacteria in 62 cases (80.5%), mostly S. aureus (n=32, 41.6%), and S. epidermidis (n=14, 18.2%) accounting for 74.2% of Gram-positive bacteria. Among 14 OAI due to S. epidermidis, 11 (78.6%) were due to methicillin-resistant strains. All the S. aureus and S. epidermidis strains were susceptible to linezolid (MICs ≤ 4 mg/L), except in one patient previously treated with linezolid who was infected with a linezolid-resistant S. epidermidis strain (MIC > 256 mg/L).

CONCLUSION

Linezolid can be used empirically in postoperative antibiotic therapy of OAI before obtaining definitive microbial results. Although linezolid resistance is rare in this population, previous oxazolidinone treatment should be documented before initiation of probabilistic postoperative treatment to highlight potential linezolid resistance.

Multidrug-Resistant Corynebacterium striatum Associated with Increased Use of Parenteral Antimicrobial Drugs

Device-related infections with this pathogen frequently require prolonged parenteral therapy.

Corynebacterium striatum is an emerging multidrug-resistant bacteria. We retrospectively identified 179 isolates in a clinical database. Clinical relevance, in vitro susceptibility, and length of parenteral antimicrobial drug use were obtained from patient records. For patients with hardware- or device-associated infections, those with C. striatum infections were matched with patients infected with coagulase-negative staphylococci for case–control analysis. A total of 87 (71%) of 121 isolates were resistant to all oral antimicrobial drugs tested, including penicillin, tetracycline, clindamycin, erythromycin, and ciprofloxacin. When isolated from hardware or devices, C. striatum was pathogenic in 38 (87%) of 44 cases. Patients with hardware-associated C. striatum infections received parenteral antimicrobial drugs longer than patients with hardware-associated coagulase-negative staphylococci infections (mean ± SD 69 ± 5 days vs. 25 ± 4 days; p<0.001). C. striatum commonly shows resistance to antimicrobial drugs with oral bioavailability and is associated with increased use of parenteral antimicrobial drugs.

Case Report - Infection of Total Knee Arthroplasty Treated with One-Stage Surgery and Linezolid

Staphylococcus spp meticillin resistant infection can be treated with Linezolid. This is a case report of an orthopaedic implant infection in a 60 year-old male treated orally with Linezolid and Rifampicin for three months after one-stage arthroplasty. This is possible provided that platelet count is closely monitored throughout the course of treatment.

Linezolid-induced lactic acidosis: the thin line between bacterial and mitochondrial ribosomes

INTRODUCTION

Linezolid inhibits bacterial growth by targeting bacterial ribosomes and by interfering with bacterial protein synthesis. Lactic acidosis is a rare, but potentially lethal, side effect of linezolid. Areas covered: The pathogenesis of linezolid-induced lactic acidosis is reviewed with special emphasis on aspects relevant to the recognition, prevention and treatment of the syndrome. Expert opinion: Linezolid-induced lactic acidosis reflects the untoward interaction between the drug and mitochondrial ribosomes. The inhibition of mitochondrial protein synthesis diminishes the respiratory chain enzyme content and thus limits aerobic energy production. As a result, anaerobic glycolysis and lactate generation accelerate independently from tissue hypoxia. In the absence of any confirmatory test, linezolid-induced lactic acidosis should be suspected only after exclusion of other, more common, causes of lactic acidosis such as hypoxemia, anemia or low cardiac output. Normal-to-high whole-body oxygen delivery, high venous oxygen saturation and lack of response to interventions that effectively increase tissue oxygen provision all suggest a primary defect in oxygen use at the mitochondrial level. During prolonged therapy with linezolid, blood drug and lactate levels should be regularly monitored. The current standard-of-care treatment of linezolid-induced lactic acidosis consists of drug withdrawal to reverse mitochondrial intoxication and intercurrent life support.

Prosthetic joint infection: managing infection in a bionic era

There is increasing demand for prosthetic joint surgery and patients are becoming more challenging due to an ageing population often with comorbidities and immunosuppression. While prosthetic joint infection (PJI) rates are generally low, infection can be catastrophic for the patient and hence prevention of infection is critical. Infection, when it does occur, is further complicated by the global rise in antimicrobial resistance. This article introduces a series of papers on the epidemiology of PJI, its diagnosis, use of novel inflammatory markers and molecular techniques, clinical presentation, importance of biofilms, treatment guidelines and, finally, various strategies and novel antibiotic treatment regimens.