Selection of an appropriate empiric antibiotic regimen in hematogenous vertebral osteomyelitis

Anterior Column Reconstruction of Destructive Vertebral Osteomyelitis at the Thoracolumbar Spine with an Expandable Vertebral Body Replacement Implant: A Retrospective, Monocentric Radiological Cohort Analysis of 24 Cases

BACKGROUND

Vertebral osteomyelitis (VO) often necessitates surgical intervention due to bone loss-induced spinal instability. Anterior column reconstruction, utilizing expandable vertebral body replacement (VBR) implants, is a recognized approach to restore stability and prevent neurological compromise. Despite various techniques, clinical evidence regarding the safety and efficacy of these implants in VO remains limited.

METHODS

A retrospective cohort analysis, spanning 2000 to 2020, was conducted on 24 destructive VO cases at a Level 1 orthopedic trauma center. Diagnosis relied on clinical, radiological, and microbiological criteria. Patient demographics, clinical presentation, surgical interventions, and radiological outcomes were assessed.

RESULTS

The study included 24 patients (62.5% male; mean age 65.6 ± 35.0 years), with 58% having healthcare-associated infections (HAVO). The mean radiological follow-up was 137.2 ± 161.7 weeks. Surgical intervention significantly improved the bi-segmental kyphotic endplate angle (BKA) postoperatively (mean -1.4° ± 13.6°). However, a noticeable loss of correction was observed over time. The study reported a mortality rate of 1/24.

CONCLUSIONS

Anterior column reconstruction using expandable VBR effectively improved local spinal alignment in destructive VO. However, the study underscores the necessity for prolonged follow-up and continuous research to refine surgical techniques and postoperative care. Addressing long-term complications and refining surgical approaches will be pivotal as the field progresses.

Risk Factors for the In-Hospital Mortality in Pyogenic Vertebral Osteomyelitis: A Cross-Sectional Study on 9753 Patients

BACKGROUND

Pyogenic vertebral osteomyelitis represents a clinical challenge associated with significant morbidity and mortality. The aim of this study was to analyze potential risk factors for the in-hospital mortality of vertebral osteomyelitis (VO) patients.

METHODS

Based on the International Classification of Diseases, 10th Revision (ICD-10) codes for VO ("M46.2-", "M46.3-", and "M46.4-") data for total case numbers, secondary diagnoses, and numbers of in-hospital deaths were extracted from the Institute for the Hospital Remuneration System (InEK GmbH). Odds ratios (OR) for death were calculated for several secondary diseases and factors of interest.

RESULTS

Despite age, certain comorbidities were found to be strongly associated with increased mortality risk: Heart failure (OR = 2.80; 95% CI 2.45 to 3.20; p < 0.01), chronic kidney disease (OR = 1.83; 95% CI 1.57 to 2.13; p < 0.01), and diabetes with complications (OR = 1.86; 95% CI 1.46 to 2.38; p < 0.01). Among the complications, acute liver failure showed the highest risk for in-hospital mortality (OR = 42.41; 95% CI 23.47 to 76.62; p < 0.01). Additionally, stage III kidney failure (OR = 9.81; 95% CI 7.96 to 12.08; p < 0.01), sepsis (OR = 5.94; 95% CI 5.02 to 7.03; p < 0.01), acute respiratory failure (OR = 5.31; 95% CI 4.61 to 6.12; p < 0.01), and systemic inflammatory response syndrome (SIRS) (OR = 5.19; 95% CI 3.69 to 5.19; p < 0.01) were associated with in-hospital mortality. When analyzing the influence of pathogens, documented infection with Pseudomonas aeruginosa had the highest risk for mortality (OR = 2.74; 95% CI 2.07 to 3.63; p < 0.01), followed by Streptococci, Escherichia coli, and Staphylococcus aureus infections.

CONCLUSIONS

An early assessment of individual patient risk factors may be beneficial in the care and treatment of VO to help reduce the risks of mortality. These findings emphasize the importance of closely monitoring VO patients with chronic organ diseases, early detection and treatment of sepsis, and tailored empirical antibiotic therapy. The identification of specific pathogens and antibiotic susceptibility testing should be prioritized to improve patient outcomes in this high-risk population.

The Epidemiology of Spondylodiscitis in Germany: A Descriptive Report of Incidence Rates, Pathogens, In-Hospital Mortality, and Hospital Stays between 2010 and 2020

BACKGROUND

Spondylodiscitis can lead to significant morbidity and mortality. Understanding its up-to-date epidemiological characteristics and trends is important to improve patient care.

METHODS

This study analyzed trends in the incidence rate of spondylodiscitis cases in Germany between 2010 and 2020, as well as the pathogens, in-hospital mortality rate, and length of hospital stay. Data were obtained from the Federal Statistical Office and the Institute for the Hospital Remuneration System database. The ICD-10 codes "M46.2-", "M46.3-" and "M46.4-" were evaluated.

RESULTS

The incidence rate of spondylodiscitis increased to 14.4/100,000 inhabitants, with 59.6% cases occurring in patients 70 years or older and affecting mainly the lumbar spine (56.2%). Absolute case numbers increased from 6886 by 41.6% to 9753 in 2020 (IIR = 1.39, 95% CI 0.62-3.08). Staphylococci and Escherichia coli were the most coded pathogens. The proportion of resistant pathogens was 12.9%. In-hospital mortality rates increased to a maximum of 64.7/1000 patients in 2020, intensive care unit treatment was documented in 2697 (27.7%) cases, and the length of stay per case was 22.3 days.

CONCLUSION

The sharply increasing incidence and in-hospital mortality rate of spondylodiscitis highlights the need for patient-centered therapy to improve patient outcomes, especially in the geriatric, frail population, which is prone to infectious diseases.

Skeletal infections: microbial pathogenesis, immunity and clinical management

Osteomyelitis remains one of the greatest risks in orthopaedic surgery. Although many organisms are linked to skeletal infections, Staphylococcus aureus remains the most prevalent and devastating causative pathogen. Important discoveries have uncovered novel mechanisms of S. aureus pathogenesis and persistence within bone tissue, including implant-associated biofilms, abscesses and invasion of the osteocyte lacuno-canalicular network. However, little clinical progress has been made in the prevention and eradication of skeletal infection as treatment algorithms and outcomes have only incrementally changed over the past half century. In this Review, we discuss the mechanisms of persistence and immune evasion in S. aureus infection of the skeletal system as well as features of other osteomyelitis-causing pathogens in implant-associated and native bone infections. We also describe how the host fails to eradicate bacterial bone infections, and how this new information may lead to the development of novel interventions. Finally, we discuss the clinical management of skeletal infection, including osteomyelitis classification and strategies to treat skeletal infections with emerging technologies that could translate to the clinic in the future.

[Current practice of empiric antibiotic treatment for spondylodiscitis]

Hintergrund und Fragestellung

Bei der pyogenen Spondylodiszitis gewinnen Infektionen mit Koagulase-negativen Staphylokokken zunehmend an Bedeutung. Eine empirische Antibiose ist insbesondere bei Patienten mit schweren oder progredienten neurologischen Ausfällen sowie hämodynamischer Instabilität und im Falle von kulturnegativen Spondylodiszitiden notwendig. Ob es in Deutschland einheitliche, an das Resistenzprofil angepasste Standards der empirische Antibotikatherapie gibt, ist unklar.

Studiendesign und Untersuchungsmethoden

Es wurde an deutschen Universitäts- und berufsgenossenschaftlichen Kliniken, jeweils in den Fachbereichen Orthopädie und Unfallchirurgie, eine Umfrage zur empirischen Antibiotikatherapie bei pyogener Spondylodiszitis durchgeführt. Die Umfrageergebnisse wurden auf das Resistenzprofil der Erreger von 45 Spondylodiszitispatienten, die zwischen 2013 und 2020 in unserer Klinik behandelt wurden, angewandt. Dadurch wurden potenzielle Sensibilitäts- und Resistenzraten für die angegebenen antibiotischen Therapien errechnet.

Ergebnisse

Von den 71 angefragten Kliniken antworteten insgesamt 44 (62,0 %). Sechzehn verschiedene Antibiotikatherapien wurden als jeweiliger Standard berichtet. Darunter wurden 14 verschiedene Kombinationstherapien als Therapiestandard angegeben. Die am häufigsten angegebenen empirischen Substanzen, nämlich Amoxicillin-Clavulansäure oder Ampicillin/Sulbactam (29,5 %) und Cephalosporine (18,2 %) zeigten in Bezug auf das zuvor veröffentliche Resistenzprofil hohe potenzielle Resistenzraten von 20,0 % bzw. 35,6 %. Die höchsten potenziellen Sensibilitätsraten wurden durch die Kombinationen Vancomycin + Ampicillin/Sulbactam (91,1 % sensible Erreger), Vancomycin + Piperacillin/Tazobactam (91,1 % sensible Erreger) und Ampicillin/Sulbactam + Teicoplanin (95,6 % sensible Erreger) erreicht. Eine dieser Kombinationen wurde von drei Kliniken (6,8 %) als Standard angegeben.

Schlussfolgerung

Die deutschlandweite Umfrage zur empirischen Antibiose bei pyogener Spondylodiszitis hat eine große Heterogenität der Standardtherapien ergeben. Eine Kombination aus einem Breitspektrum-β-Laktam-Antibiotikum mit einem zusätzlichen Glykopeptidantibiotikum kann sinnvoll sein.

Comparative study of culture, next-generation sequencing, and immunoassay for identification of pathogen in diabetic foot ulcer

Treatment of deep musculoskeletal infection (MSKI) begins with accurate identification of the offending pathogen, surgical excision/debridement, and a course of culture-directed antibiotics. Despite this, the incidence of recurrent infection continues to rise. A major contributor to this is inaccurate or negative initial cultures. Accurate identification of the main pathogen is paramount to treatment success. This is especially important in treating diabetic foot infections (DFIs) with limb salvage efforts. This study seeks to utilize standard culture, next-generation sequencing (NGS), and immunoassay for newly synthesized antibodies (NSA) to Staphylococcus aureus and Streptococcus agalactiae for diagnosis. This is a level II prospective observational study approved by our IRB. Thirty patients > 18 years of age who presented with a DFI and underwent surgical debridement or amputation by a single academic orthopedic surgeon from October 2018 to September 2019 were enrolled. Intraoperative samples were obtained from the base of the wound and sent for culture, NGS, and a peripheral blood sample was obtained at the time of diagnosis. NGS and culture were highly correlated for S. aureus (κ = 0.86) and S. agalactiae (κ = 1.0), NSA immunoassay and culture demonstrated a fair correlation for S. aureus (κ = 0.18) and S. agalactiae (κ = 0.67), and NGS and NSA immunoassay demonstrated fair correlation for S. aureus (κ = 0.1667) and S. agalactiae (κ = 0.67). Our study demonstrates a high concordance between culture and NGS in identifying the dominant pathogen in DFU. NGS may be a useful adjunct in DFI diagnosis.

[Common infectious challenges of the thoracic and lumbar spine : Spondylodiscitis and postoperative wound infection]

Spondylodiscitis and postoperative wound infections are the most frequent infectious diseases of the thoracic and lumbar spine. Every spinal surgeon will come into contact with such patients during his or her career. Knowledge particularly of the diagnostics, conservative and surgical treatment as well as microbiological considerations of antibiotic treatment are therefore of particular importance and are explained in this article.

Is There a Difference in Clinical Features, Microbiological Epidemiology and Effective Empiric Antimicrobial Therapy Comparing Healthcare-Associated and Community-Acquired Vertebral Osteomyelitis?

Background: Empiric antibiotic therapy for suspected vertebral osteomyelitis (VO) should be initiated immediately in severely ill patients, and might be necessary for culture-negative VO. The current study aimed to identify differences between community-acquired (CA) and healthcare-associated (HA) VO in terms of clinical presentation, causative pathogens, and antibiotic susceptibility. Methods: Cases of adult patients with VO treated at a German university orthopaedic trauma center between 2000 and 2020 were retrospectively reviewed. Patient history was used to distinguish between CA and HA VO. Susceptibility of antibiotic regimens was assessed based on antibiograms of the isolated pathogens. Results: A total of 155 patients (with a male to female ratio of 1.3; and a mean age of 66.1 ± 12.4 years) with VO were identified. In 74 (47.7%) patients, infections were deemed healthcare-associated. The most frequently identified pathogens were Staphylococcus aureus (HAVO: 51.2%; CAVO: 46.8%), and Coagulase-negative Staphylococci (CoNS, HAVO: 31.7%; CAVO: 21.3%). Antibiograms of 45 patients (HAVO: n = 22; CAVO: n = 23) were evaluated. Significantly more methicillin-resistant isolates, mainly CoNS, were found in the HAVO cohort (27.3%). The highest rate of resistance was found for cefazolin (HAVO: 45.5%; CAVO: 26.1%). Significantly higher rates of resistances were seen in the HAVO cohort for mono-therapies with meropenem (36.4%), piperacillin–tazobactam (31.8%), ceftriaxone (27.3%), and co-amoxiclav (31.8%). The broadest antimicrobial coverage was achieved with either a combination of piperacillin–tazobactam + vancomycin (CAVO: 100.0%; HAVO: 90.9%) or meropenem + vancomycin (CAVO: 100.0%; HAVO: 95.5%). Conclusion: Healthcare association is common in VO. The susceptibility pattern of underlying pathogens differs from CAVO. When choosing an empiric antibiotic, combination therapy must be considered.

Secondary Infection/Microbial Substitution in a Managed Case of Pyogenic Spondylitis

Pyogenic spondylitis is a challenging condition that requires early and accurate diagnosis for appropriate treatment. Most cases can be treated non-surgically or with minimally invasive surgical procedures; however, a combination of anterior debridement/bone grafting and posterior fixation is necessary for severe cases. We encountered a case of lumbar pyogenic spondylitis treated with anterior debridement and autogenous bone grafting after percutaneous endoscopic discectomy drainage (PEDD) with percutaneous pedicle screw (PPS) fixation. The continuous pus oozing from the PEDD drainage tube wound was characteristic in this case, and the pus was considered to be caused by secondary infection/microbial substitution. The discharge immediately stopped and healed after anterior debridement and autogenous bone grafting. Escherichia coli was first detected as the causative bacterium, and Corynebacterium amycolatum and Corynebacterium striatum were detected as the cause of secondary infection/microbial substitution. The possibility of secondary infection/microbial substitution should be considered when the clinical course worsens.

Treatment and Clinical Outcomes of Osteoarticular Infections Among Pediatrics Admitted to Jimma University Medical Center, Ethiopia: A Prospective Observational Study

BACKGROUND

Despite the high burden of osteoarticular infections in sub-Saharan Africa, there is a paucity of data regarding the osteoarticular infections management approach and clinical outcomes in the region. Hence, this study aimed to evaluate a management protocol, clinical outcomes, and its determinants among pediatric patients with osteoarticular infections.

METHODS

A pediatric patient admitted to Jimma University Medical Center (JUMC), Ethiopia, with a diagnosis of osteoarticular infections was enrolled prospectively from April 30 to October 30, 2019. Clinical characteristics, management modality, and in-hospital complications were recorded from admission to discharge. Data were analyzed by using SPSS v.23 and the p-value <0.05 was considered statistically significant.

RESULTS

Among a total of 150 pediatric patients enrolled in this study, osteomyelitis was diagnosed in 111 (74%), while the rest 39 (26%) had septic arthritis. The majority 105 (70%) of the study participants were male with a mean age of 8.79 ± 4.2 years. The culture was performed for only 3.6% of the patients. Almost all (98.7%) of the patients received intravenous (IV) antibiotics, and ceftriaxone was the most common IV antibiotic used as a monotherapy 66 (44.6%) or in combination with metronidazole 47 (31.8%) or gentamicin (12.8%). Almost half (45.3%) of the patients had poor treatment outcomes. Factors associated with poor treatment outcome were comorbidity [AOR=3.3, 95% CI (1.08-10.16)] and use of combination antibiotics [AOR=2.9, 95% CI (1.16-7.3)]. Rural residence [AOR=0.39, 95% CI (0.168-0.92)] and surgical interventions [AOR=0.29, 95% CI (0.006-0.144)] were associated with good treatment outcomes.

CONCLUSION

Almost half of pediatric patients with osteoarticular infections had poor treatment outcome. Health providers should increase the accessibility of microbiological tests and diagnostic imaging, which can guide treatment decisions and improve outcomes of patients with osteoarticular infections.

Does image-guided biopsy of discitis-osteomyelitis provide meaningful information to impact clinical management?

OBJECTIVE

The aims of this study are to assess the diagnostic yield of image-guided biopsy for discitis-osteomyelitis (DO), identify factors associated with biopsy yield (laboratory, pre-defined MRI findings, and biopsy technique), and impact of biopsy on management of patients appropriately selected according to the Infectious Disease Society of America guidelines (IDSA).

MATERIALS AND METHODS

This is a retrospective review of patients who underwent biopsy for suspected DO from 2011 to 2019. Reference standards to establish diagnosis of DO in order were histopathology/microbiology from biopsy or subsequent surgical sampling, positive blood culture or serology, and imaging/clinical follow-up. Laboratory markers, pre-biopsy antibiotics and MRI features, procedural-related variables, and impact of biopsy on management were assessed. Multivariable logistic regression was also performed.

RESULTS

Out of 97 included patients, 78 were diagnosed with DO. Overall sensitivity of biopsy for detecting DO was 41.0% (32/78), including 10 patients with positive histopathology only, 14 with positive biopsy culture only, and 8 with both. Elevated ESR (p < 0.001) and epidural collection on MRI (p = 0.008) were associated with higher biopsy yield (63.6% and 68.6%, respectively) in a multivariable model. Procedural variables were not associated with yield. Biopsy results impacted the management in 19/77 (24.7%) patients, of whom 15/19 (78.9%) had treatment de-escalation and 4/19 (21.0%) had treatment escalation including starting new anti-tuberculous and anti-fungal regimens.

CONCLUSION

Sensitivity of biopsy for detecting DO was 41.0%. When IDSA guidelines are followed, biopsy provided impactful information that changed the management in 24.7% of patients. Evaluation for elevated ESR and epidural collection can help improve yield and patient selection for biopsy.

Case report of infective spondylodiscitis due to nalidixic acid-resistant Salmonella paratyphi A

Spondylodiscitis due to typhoidal Salmonella presents a therapeutic challenge for clinicians. Factors that complicate treatment include drug-resistant strains, poor antibiotic bone penetration, potential for neurological compromise and lack of established protocols and guidelines. We discuss a 57-year-old man with Salmonella paratyphi A spondylodiscitis involving lower thoracic vertebrae and discuss various aspects of management.

Microbiologic Diagnosis of Pyogenic Spondylitis

Pyogenic spondylitis requires long-term antibiotics treatment and identification of the etiologic microorganism is essential. The first test in the microbiologic diagnosis of pyogenic spondylitis is a blood culture. Any microorganisms that grow in blood culture are highly likely to be the etiological microorganisms of pyogenic spondylitis. If the microbial etiology cannot be defined by the blood culture, a needle biopsy is performed on the inflamed tissues. Here, it is recommended that paraspinal tissues, rather than spinal tissues, are collected to increase the positive rate in tissue culture. If the microbial etiology cannot be defined by the first needle biopsy, another needle biopsy may be performed. The collected tissue sample is used in culture tests on bacteria and mycobacteria as well as pathological tests. If tuberculous spondylitis is suspected, polymerase chain reaction is carried out to detect Mycobacterium tuberculosis. In the case that the etiological microorganisms cannot be identified, the data of the patient regarding age, sex, vertebrae involved, history of spinal surgery or procedure, previous or concurrent urinary tract or intra-abdominal infection are analyzed. Based on this the most probable microbial etiology is determined to select the antibiotics to be used in the empiric treatment.

Microbiological diagnosis of suspected vertebral osteomyelitis with a focus on the yield of percutaneous needle biopsy: a 10-year cohort study

This study aims to evaluate in patients hospitalized for vertebral osteomyelitis (VO) the effectiveness of bacteriological diagnosis and the yield of percutaneous needle biopsy (PNB) and to identify factors associated with the result of PNB. This retrospective, two-centre study was conducted between 2000 and 2009. Data on patients with VO were retrieved from the diagnosis database and confirmed by checking medical records. A total of 300 patients with VO were identified; 31 received antibiotics without bacteriological diagnosis, and 269 patients with spondylodiscitis imaging were included. Eighty-three (30.9%) and 18 (6.7%) infections were documented by blood cultures and by bacteriological samples other than PNB, respectively; 168 patients with no bacteriological diagnosis had PNB. Of these, 92 (54.8%) were positive and identified the pathogen and 76 (45.2%) were negative. The most common bacteria were Staphylococcus aureus (34.3%), Streptococcus spp. (20.6%) and coagulase-negative staphylococcus (14.8%). After multivariate analysis, the only factor associated with negative PNB was previous antibiotic intake (OR: 2.31 [1.07-5.00]). When VO was suspected on imaging, bacteriological investigation identified the microorganism in 209/300 (70%) of the cases. The yield of PNB was 54.8%. The only predictor of PNB negativity was previous antibiotic intake. Therefore, we believe that a second PNB should be done after a sufficient delay withdrawal of antibiotics if the first sample was negative. The study was retrospectively registered by the local ethics committee (N°E2019-61).

Microbial Etiology of Pyogenic Vertebral Osteomyelitis According to Patient Characteristics

Background

It is difficult to select an appropriate empirical antibiotic treatment regimen for patients with culture-negative pyogenic vertebral osteomyelitis (PVO). Having knowledge of the distribution of microorganisms according to patient characteristics can help clinicians make informed choices regarding empirical antibiotics. The aim of this study was to determine the microbial distribution among individuals with PVO according to their demographic and clinical characteristics.

Methods

We reviewed the medical records of patients admitted to our hospital with culture-confirmed PVO between January 2005 and December 2017 and collected data on demographics, underlying diseases, and radiographic and microbiological results. Statistical analysis was performed to identify associations between specific bacteria and specific patient characteristics.

Results

A total of 586 patients were included in the study. The prevalence of Staphylococcus aureus infections was higher in young patients than in old patients, while gram-negative bacterial infections and Enterococcus were more prevalent in older patients. Gram-negative bacterial infections were more common in women than in men (32.1% vs 16.4%; P < .05), in patients with cirrhosis than in those without (32.7% vs 21.1%; P < .05), and in patients with a solid tumor than in those without (31.0% vs 20.7%; P < .05). Methicillin-resistant S. aureus infections were more prevalent in patients with chronic renal disease than in those without (34.4% vs 14.7%; P < .05).

Conclusions

The microbial etiology of PVO varies according to patient characteristics. Patient characteristics should thus be considered when choosing empirical antibiotics in patients with culture-negative PVO.

Etiology, characteristics, and outcomes of community-onset necrotizing fasciitis in Korea: A multicenter study

Background

Necrotizing fasciitis (NF) is a serious skin and soft tissue infection causing high mortality. Investigating region specific epidemiologic factors associated with NF is important for establishing appropriate treatment strategies. This multicenter study was done to provide an update of the microbial etiology, clinical characteristics, and outcomes of NF in Korea.

Materials and methods

A retrospective cohort of adult patients with NF was established using patient data from 13 general hospitals between January 2012 and December 2015 in Korea. We evaluated microbial etiology and clinical characteristics to identify risk factors associated with in-hospital mortality; analyses were performed using binary logistic regression models.

Results

A total of 161 patients with NF were included. The most common underlying disease was diabetes mellitus (66 cases, 41.0%). A total of 148 organisms were isolated from 119 (73.9%) patients. Enteric Gram-negative organisms (36 patients) were the most common pathogen, followed by Staphylococcus aureus (30 patients) and streptococci (28 patients). Methicillin-resistant Staphylococcus aureus (MRSA) was identified in 6.2% (10/161) of patients. Of 37 enteric Gram-negative isolates tested, 26 (70.3%) isolates were susceptible to ceftriaxone. The in-hospital mortality rate was 22.4%. Intensive care unit admission, septic shock, and Gram-negative organism infections were significantly associated with in-hospital mortality, and surgery was not a favorable prognostic factor.

Conclusions

As initial empirical antibiotics, glycopeptides against MRSA and broad-spectrum antibiotics against third-generation cephalosporin-resistant organisms should be considered for patients with community-onset NF in Korea.

Antibiotic Treatment of Vertebral Osteomyelitis caused by Methicillin-Susceptible Staphylococcus aureus: A Focus on the Use of Oral β-lactams

BACKGROUND

Vertebral osteomyelitis (VO) is a rare but serious condition, and a potentially significant cause of morbidity. Methicillin-susceptible Staphylococcus aureus (MSSA) is the most common microorganism in native VO. Long-term administration of parenteral and oral antibiotics with good bioavailability and bone penetration is required for therapy. Use of oral β-lactams against staphylococcal bone and joint infections in adults is not generally recommended, but some experts recommend oral switching with β-lactams. This study aimed to describe the current status of antibiotic therapy and treatment outcomes of oral switching with β-lactams in patients with MSSA VO, and to assess risk factors for treatment failure.

MATERIALS AND METHODS

This retrospective study included adult patients with MSSA VO treated at nine university hospitals in Korea between 2005 and 2014. Treatment failure was defined as infection-related death, microbiological relapse, neurologic deficits, or unplanned surgical procedures. Clinical characteristics and antibiotic therapy in the treatment success and treatment failure groups were compared. Risk factors for treatment failure were identified using the Cox proportional hazards model.

RESULTS

A total of 100 patients with MSSA VO were included. All patients were treated, initially or during antibiotic therapy, with one or more parenteral antibiotics. Sixty-nine patients received one or more oral antibiotics. Antibiotic regimens were diverse and durations of parenteral and oral therapy differed, depending on the patient and the hospital. Forty-two patients were treated with parenteral and/or oral β-lactams for a total duration of more than 2 weeks. Compared with patients receiving parenteral β-lactams only, no significant difference in success rates was observed in patients who received oral β-lactams for a relatively long period. Sixteen patients had treatment failure. Old age (adjusted hazard ratio [HR] 5.600, 95% confidence interval [CI] 1.402 - 22.372, P = 0.015) and failure to improve C-reactive protein levels at follow-up (adjusted HR 3.388, 95% CI 1.168 - 9.829, P = 0.025) were independent risk factors for treatment failure.

CONCLUSION

In the study hospitals, diverse combinations of antibiotics and differing durations of parenteral and oral therapy were used. Based on the findings of this study, we think that switching to oral β-lactams may be safe in certain adult patients with MSSA VO. Since limited data are available on the efficacy of oral antibiotics for treatment of staphylococcal VO in adults, further evaluation of the role of oral switch therapy with β-lactams is needed.