Positive Intraoperative Cultures Research Articles

The fate of positive intraoperative cultures following conversion total hip arthroplasty.

The objectives of this study are to report the rates of positive intraoperative cultures obtained during conversion total hip arthroplasty (THA) according to index surgery, and to describe the natural history of treatment for a consecutive series of patients with unexpected positive intraoperative cultures during conversion THA. We reviewed all patients at 2 institutions undergoing conversion THA from prior open reduction and internal fixation (ORIF) of acetabular and hip fractures or hemiarthroplasty for displaced femoral neck fractures from 2011 to 2018. Intraoperative cultures were taken in 105 patients. Positive intraoperative cultures during conversion were recorded and managed with an infectious diseases consult. The outcomes including PJI at 90 days and 1 year follow-up were documented. Overall, 19 of 105 patients (18%) undergoing conversion THA had positive intraoperative cultures, with the highest rates in the hemiarthroplasty 7/16 (44%) and acetabular ORIF 9/48 (19%) groups. All 19 patients were initially treated conservatively: 8 received IV antibiotics, 10 received no additional therapy, and 1 received oral antibiotics. 4/9 acetabular fracture conversions developed PJI at 1 year, with 3 requiring multiple irrigation and debridement/polyethylene exchanges to control the infection while the 4th patient required 2-stage exchange. There were no 1-year PJI from any of the other index procedures after conversion. All 7 hemiarthroplasty patients with positive cultures were treated to resolution with 4-8 weeks IV antibiotics alone. Patients undergoing conversion THA from prior hip or acetabular fracture have a high rate of positive intraoperative cultures. As such, all patients undergoing conversion THA from prior hip or acetabular fracture fixation should undergo thorough diagnostic workup prior to surgery, and have intraoperative cultures obtained during surgery if infection remains suspicious. Further work should be performed to develop MSIS criteria for preoperative management of patients undergoing conversion THA.

Risk factors and clinical features of purulent-inflammatory diseases of the pelvic organs given the microbial factor

Determination of risk factors and clinical features of purulent-inflammatory diseases of the pelvic organs given the microbial factor.Material and methods. A retrospective analysis of medical records of 47 patients undergoing urgent surgical treatment for purulent-inflammatory diseases of the pelvic organs in the city clinical hospital №1 of the city of Odessa in the gynecological ward for 2014-2019 was conducted.Results. The average age of the patients was 38.3±1.5 years. Patients were in the hospital on average 10.5±0.5 days. It was found that the onset of sexual activity in patients was 14.6±1.66 years. Postoperative purulent-septic complications were observed in 18 women (38.3%). 13 women in life had an artificial termination of pregnancy, that is, 72.2% (RR=1.22). For 30 cases (63.8%) of positive intraoperative bacterial culture, 22 women (73.3%) had a history of artificial termination of pregnancy (OR=1.93). Monoculture was determined in 24 patients (80.0%), and microbial associations in 6 patients (20.0%). A relationship was found between the presence of microbial association and the presence in the woman's history of artificial abortions (RR=1.67). Sexually transmitted diseases during history taking were noted by 19 women, which amounted to 40.4%. Of these, postoperative purulent-septic complications were observed in 12 patients (RR=2.94).Conclusions. 1. When assessing the relative risk, it was found that previously transmitted sexually transmitted diseases, artificial abortions, an early debut of sexual activity, a low level of contraceptive culture and promiscuity are of the greatest importance for the development of purulent-inflammatory diseases of the pelvic organs. 2. It is shown that the presence in a woman's history of artificial abortions increases the risks of a purulent-inflammatory process. So out of 18 patients in whom the development of postoperative purulent-septic complications was observed, 13 women had a history of artificial termination of pregnancy, that is, 72.2% (RR=1.22). 3. The frequency of purulent-septic complications depends on the severity of the patient's condition and signs of general intoxication. So, in patients undergoing community-acquired abortion, the incidence of purulent-septic complications was 100%, and the average number of leukocytes was 22.0±3.0 (RR=3.3, p <0.05).

Incidence and predictors of positive intraoperative cultures in primary shoulder arthroplasty following prior ipsilateral shoulder surgery

BackgroundTo our knowledge, the rate of positive intraoperative cultures in patients undergoing primary shoulder arthroplasty with prior ipsilateral nonarthroplasty shoulder surgery is unknown. The aim of this study was to determine the incidence and predictors of positive cultures in these patients.MethodsWe performed a retrospective review of patients with prior ipsilateral shoulder surgery with intraoperative cultures taken at the time of primary shoulder arthroplasty. We evaluated culture results, demographics, and number of prior surgeries. Regression analysis was used to determine patient-related risk factors that predict positive cultures.ResultsA total of 682 patients underwent primary shoulder arthroplasty, 83 had at least 1 prior ipsilateral shoulder surgery: 65.1% male, mean age 64.2 ± 10.9 years. For the cohort of 83 patients, an average of 3.2 ± 1.2 tissue samples were obtained for each patient, with a mean of 0.84 ± 1.14 tissue cultures being positive (range 0-5). Thirty-seven of the 83 patients (44.5%) had at least 1 positive culture, with Cutibacterium acnes the most frequent organism (31/37; 83.4%). An average of 1.9 ± 0.96 tissue cultures resulted positive (range 1-5) for the 37 patients who had positive cultures, 40.5% (15/37) had only 1 positive tissue culture (12/15 C acnes, 2/15 Staphylococcus epidermidis, and 1/15 vancomycin-resistant enterococcus). Male sex and history of prior shoulder infection were predictive of culture positivity (odds ratios: 2.5 and 20.9, respectively). Age, race, medical comorbidities, number of prior shoulder surgeries, and time from index shoulder surgery were not predictive of culture positivity.ConclusionAbout 45% of patients with no clinical signs of infection and a history of prior ipsilateral shoulder surgery undergoing primary shoulder arthroplasty grew positive intraoperative cultures. The significance of these findings remains unclear with regard to risk of periprosthetic infection and how these patients should be managed.

The Value of Serological Screening Prior to Conversion Total Hip Arthroplasty

BackgroundThis study sought (1) to assess the value of serological testing prior to conversion total hip arthroplasty (THA) in predicting infection and (2) to identify optimal serological values for routine diagnostic workup prior to conversion THA. MethodsAll patients at our tertiary referral center undergoing conversion THA after hip/acetabular fracture procedure from 2013 to 2018 were retrospectively reviewed. Inclusion criteria were patients previously undergoing hemiarthroplasty or open reduction and internal fixation of acetabular, intertrochanteric, and subtrochanteric fractures that progressed to conversion THA due to post-traumatic arthritis having erythrocyte sedimentation rate/C-reactive protein (CRP) prior to conversion. Infection was defined as positive intraoperative cultures not deemed contaminant in collaboration with infectious disease consult and/or development of PJI within 1 year postoperatively. ResultsTwelve of 87 (14%) patients undergoing conversion THA developed infection. The mean erythrocyte sedimentation rate (37.2 vs 24.4 mm/h, P = .2062) and CRP (22.4 vs 9.0 mg/L, P = .0026) in the infected cohort were elevated compared to the noninfected group. An optimal cutoff value for CRP of 12 mg/L (area under the curve = 0.77, 95% confidence interval 0.58-0.97) revealed 75% sensitivity, 84% specificity, 43% positive predictive value, and 95% negative predictive value (P < .0001) in the entire cohort. ConclusionsEven without clinical signs and symptoms, patients undergoing conversion THA from internal fixation of hip/acetabular fractures are still at high risk for developing periprosthetic joint infection. All patients undergoing conversion THA should have CRP measured preoperatively as a part of the diagnostic workup for underlying infection. Further research should be devoted to creating a preoperative diagnostic algorithm incorporating CRP, similar to Musculoskeletal Infection Society criteria, dedicated to patients undergoing conversion THA. Level of EvidenceLevel III, Diagnostic retrospective cohort study.

Prevalence and Impact of Positive Intraoperative Cultures in Partial Hip or Knee Revision

BackgroundOur aim is to investigate the impact of unexpected positive cultures on the outcome of partial prosthetic revisions. MethodsData regarding patients who underwent a partial hip or knee revision from 2003 and 2012 with the preoperative diagnosis of aseptic loosening was retrospectively reviewed. The protocol of revision included at least 3 intraoperative cultures. Failure was defined as the need for re-revision due to aseptic or septic loosening at 5 years. ResultsA total of 99 hip and 46 knee partial revisions were included. All cases had at least 5 years of follow-up. Ninety-seven cases (66.9%) had all cultures negative, 35 (24.1%) a single positive culture and 13 (9.0%) ≥2 positive cultures for the same microorganism. The median time from primary arthroplasty to partial revision was significantly shorter for patients with ≥2 positive cultures (26 months) than in those with all cultures negative (48 months) or with a single positive culture (51 months). Partial revisions performed within the first 5 years of implantation had a higher 5-year re-revision rate. The presence of a single positive culture during the partial exchange was not associated with a higher re-revision rate (2 of 35, 5.7%) than in those with negative cultures (3 of 97, 3.1%). On the contrary, re-revision rate was significantly higher in cases with ≥2 positive cultures (3 of 13, 23.1%) than in those with negative cultures (P = .02). ConclusionPartial revisions performed within the first 5 years from implantation and ≥2 intraoperative positive cultures were associated with a higher re-revision risk at 5 years.

Informativeness of bone intraoperative culture for diagnose osteomyelitis in diabetic foot patients.

BACKGROUND: Diagnosis of osteomyelitis in diabetic foot patients is frequently not obvious due to similar clinical and X-ray signs of bone infection and Sharcot osteopathy, but it is very important because of opposite approach to treatment of these conditions. Today we do not have reliable parameters to determine the devastation of bone infection and, therefore, the rational volume of bone resection and debridement.&#x0D; AIMS: To determine the diagnostic value of bone culture for osteomyelitis in diabetic foot patients.&#x0D; MATERIALS AND METHODS: 177 patients underwent surgery due to different forms of diabetic foot. In 131 of them clinical signs of osteomyelitis were revealed and this diagnosis was confirmed by histology. 46 patients with diabetes who underwent high-level amputation without bone infection formed the control group. Intraoperative bone cultures and histological samples were taken in all cases.&#x0D; RESULTS: We found similar microbial landscape in various forms of diabetic foot and in control group. The frequency of positive intraoperative cultures in patients without osteomyelitis was detected as 63%. The sensitivity of bone culture was counted as 86,3%, the specificity as 37%, the accuracy 73.5%.&#x0D; CONCLUSIONS: Our findings suggest that bone culture is not reliable sign of bone infection in diabetic foot patients due to its low specificity. In our judgment, the only way to determine rational level of bone resection is visual intraoperative assessment and clinical signs such as development of granulation tissue and wound healing.

Perioperative Hyperglycemia as a Risk Factor for Early Surgical-Site Infection in Stable Trauma Patients in Orthopedic Unit

Introduction: Perioperative hyperglycemia resulted from known diabetes mellitus, occult diabetes or stressed-induced hyperglycemia. It is associated with increasing risk of surgical-site infection (SSI). This research is to evaluate relationship between perioperative hyperglycemia and early SSI in stable trauma patients with orthopaedic injuries. Materials and method: We conducted an observational cohort study in Hospital Sultanah Nur Zahirah, Kuala Terengganu over 15 months. We included patients 18 years and older with operative orthopaedic injuries and excluded those with steroid use, multisystem injuries, critically ill or unstable and patients with perioperative infection. Demographics, medical comorbidities, body mass index, type of fracture, HbA1c level in diabetic patients and length of hospital stay were recorded. Fingerprick glucose values were obtained twice daily. Hyperglycemic index (HGI), an area under the glucose curve above the normal range divided by the length of stay, were calculated. Perioperative hyperglycemia was defined by HGI greater than 1.76. SSI was defined by gross purulence or positive intraoperative culture at reoperation within 30 days. The categorical data were analysed using chi square test while continuous data were analysed using T-test. Results: Total of 90 patients, 15-diabetic and 75 non-diabetic. 10 diabetic and 1 non-diabetic patients were hyperglycemic (p=0.001). Perioperative hyperglycemia was associated with mean age 54.3 year old, having 1 or more co-morbidity or mean admission glucose 13.1 mmol/L (p=0.001). There were 12 early SSI giving infection rate 13.3%. Early SSI was associated with HGI 1.76 and more (p=0.001), patients with 1 or more co-morbidity (p=0.006), mean admission glucose of 9.63 mmol/L (p=0.001). Conclusion: Our study showed perioperative hyperglycemia in stable trauma patients with orthopaedic injuries were associated with SSI. More patients are needed to find association of other variables and more studies are required in determining the acceptable glucose level and optimal treatment of perioperative hyperglycemia in stable trauma patients.

Importance of the Algorithm for Diagnosis of Late Deep Periprosthetic Hip Infection

Relevance. Late deep periprosthetic infection (PJI) of the hip joint is a serious complication after arthroplasty which takes the lead among the world reasons for revision. Accurate diagnostics allows to achieve good results and select a proper treatment tactics. Purpose of the study — to evaluate the efficiency of diagnostics algorithm for late deep PJI and impact of the microbial landscape on the risk of infection recurrence. Materials and methods. The authors evaluated two groups of patients who underwent revision in the period from 2002 to 2014 and from 2015 to 2018. The first (retrospective) group included 144 patients who were not diagnosed for late deep PJI. The second (prospective) group included 157 patients who underwent detailed diagnostics for late deep PJI based on the algorithm including the analysis of x-rays, pelvic CT, triple evaluation of ESR and CRP, puncturing of affected joint and microbiology examination. The authors assessed the microbial landscape in 51 patients with late deep hip PJI. Results. In the first group 12 patients (8.3%) underwent sanation and spacer insertion during first stage of treatment, 46 patients (59.7%) after revision demonstrated positive intraoperative cultures confirming septic etiology of implant loosening, 19 patients (24.67%) had no flora growth, and no intraoperative microbiological examination was done for remaining 67 patients (46.52%). In the second group after detailed diagnostics 51 patients (32.4%) underwent removal of prosthesis and spacer insertion in the first stage, other 13 patients (8.2%) featured flora growth after revision, remaining 93 patients (59.2%) had no flora growth after revision. Recurrent PJI was observed in 21 patients (14.5%) in the first group, and in 10 patients (6.3%) in the second group. In the second group recurrent PJI was reported in 40% of patients due to microbial associations, in 30% — due to MRSA, in 20% — due to culture negative bacteria and in 10% — due to S. aureus. Conclusion. Triple examination allows to obtain an accurate diagnosis and isolate the pathogen for deep PJI. Application of such diagnostics algorithm allows to reduce 2.1 times the risk of recurrent deep PJI and to scale down 4 times the detection of type IV infection by Coventry–Tsukayama classification.

The feasibility of outpatient conversion and revision hip arthroplasty in selected patients.

Total hip arthroplasty (THA) continues moving to the outpatient arena, and may be feasible for some conversion and revision scenarios. Controversy surrounds appropriate patient selection. The purpose of this study is to report complications associated with outpatient revision and conversion THA, and to determine if comorbidities are associated with complications or overnight stay. From June 2013 through August 2018, 46 patients (47 hips) underwent conversion (n = 10) or revision (n = 37) THA at a free-standing ambulatory surgery centre. This represented only 6.3% of revision THA cases at our institution during the study period that were selected for outpatient surgery. Mean patient age was 58.0 years, and 52% of patients were males. 1 or more major comorbidities were present in 15 patients (32%) including 1 valvular disease, 7 arrhythmia, 2 thromboembolism history, 3 obstructive sleep apnoea, 3 chronic obstructive pulmonary disease, 2 asthma, 4 frequent urination, and 1 renal disease. 44 (94%) patients were discharged same day without incident, none required transfer to acute facility, and 3 stayed overnight (2 convenience, 1 for medical reasons - urinary retention). The patient kept overnight for medical reasons had no major comorbidities. 3 patients were placed on an extended course of antibiotics, including 2 with positive intraoperative cultures and 1 for cellulitis. There were no major complications, readmissions, or subsequent surgeries within 90 days. Outpatient revision hip arthroplasty is safe in selected patients undergoing minor or partial revisions. Presence of medical comorbidities was not associated with risk of complications. Medical optimisation and a multimodal programme to mitigate risk of blood loss and reduce narcotic need facilitate the safe performance of arthroplasty in an outpatient setting.

Positive "Surprise" Broth Cultures in Nonunion Surgery Do Not Require Antibiotic Treatment.

The objective of this study was to review the efficacy of a treatment approach for patients with positive intraoperative cultures during fracture nonunion surgery. The authors performed a retrospective case series at a level I trauma center. In this series, 60 patients without preoperative concern for infection were surgically treated for fracture nonunion. The treatment course of patients after fracture nonunion surgery, including culture results, antibiotic administration, and the presence of clinical infection and radiographic union, was studied. Sixty patients underwent fracture nonunion surgery. Twenty-four patients had a positive intraoperative culture. Fourteen patients had only a positive broth culture, 6 had only a positive routine culture, and 4 had positive mixed (routine and broth) cultures. The most common bacteria was coagulase-negative staphylococci, isolated in 19 of 24 patients, and the only isolated organism in 13 of 24 patients. Patients with a positive broth culture were not treated with antibiotics. Four of 10 patients with either a positive routine or mixed culture grown within 3 days of surgery were treated with antibiotics. All patients achieved clinical healing without signs of infection, and all but 2 patients achieved radiographic union at a mean follow-up of approximately 5 years. In the setting of fracture nonunion surgery, patients with only a positive broth culture and those with only a positive routine or mixed cultures that grew in a delayed fashion (>3 days postoperatively) did not require antibiotic treatment to achieve healing. [Orthopedics. 2019; 42(6):e532-e538.].

Clinical analysis of intraoperative bile in hepatopancreatic and biliary surgeries

Introduction: Around the globe among the commonest performed surgeries the hepaticopancreatic and biliary surgies are one of them. However these are still associated with serious infections. The presence of bacteria at the time of surgery predisposes to septic complications. Materials and Methods: This study was a prospective study conducted in Department of Surgical Gastroenterology at Sher-i-Kashmir Institute of Medical Sciences from September 2016 to September 2018. Results: The most common age group in our study included middle aged patients i.e 35-44 years of age, out of 50 patients 62% had positive intraoperative bile culture. The most common organism found in our study was: E coli and k. pneumonia in 33.9%, E coli and Enterococcus faecalis 21%, The monomicrobial infection was due to E coli 11.3%, Preoperative stented patients had 88% of bactibilia. Conclusion: The preoperative biliary stenting is associated with increased risk of bactibilia and bactibilia leads to increase in postoperative morbidity in pancreatic biliary surgeries. E coli and kleibsella predominated in bile. Similar microorganisms predominate in wound cultures and intraabdominal collections. E coli were found to be resistant to most of the commonest drugs.

22. Subclinical infection as an etiology for pseudarthrosis in multilevel thoracolumbar spinal fusions

BACKGROUND CONTEXT Pseudarthrosis is a common indication for revision spine operations. Clinical presentations of pseudarthrosis are heterogeneous. While the majority of patients present with pain, many can be symptomatic. Etiologies of pseudarthrosis also vary from structural to biologic, including infection. PURPOSE To determine prevalence of subclinical infection and identify risk factors associated with positive intraoperative cultures in revisions for lumbar pseudarthrosis. STUDY DESIGN/SETTING Single-center retrospective cohort. PATIENT SAMPLE Adults who underwent revision posterior instrumented fusions for lumbar pseudarthrosis. OUTCOME MEASURES Intraoperative microbiological analysis. METHODS Retrospective review of adults who underwent revision posterior instrumented fusions for lumbar pseudarthrosis at a single institution. All patients had intraop cultures obtained regardless of clinical suspicion for infection. Patients with overt infection were excluded. Demographic, medical, and surgical data were analyzed for association with positive cultures and instrumentation failure. RESULTS Fifty-one patients (avg age 59.1±13.2 years, female-28, avg # prior operations 3.2±2.8) were included. Seventeen (33.3%) had at least 1 positive intraop culture, and 7 (13.7%) had ≥2 positive intraop cultures. Instrumentation failure was evident in 14 (27.5%) patients. Female gender was associated with decreased odds of having ≥2 positive intraop cultures (OR=0.10, p CONCLUSIONS One third of patients undergoing revision for lumbar pseudarthrosis had subclinical infection (positive intraoperative culture). As such, intraoperative cultures should ideally be routinely obtained in the revision setting for lumbar pseudarthrosis and/or instrumentation failure regardless of clinical suspicion for infection. Further studies are necessary to identify risks of subclinical infection leading to pseudarthrosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

The utility of preoperative and intraoperative cultures for guiding urosepsis empirical treatment

Objective: Endoscopic upper urinary tract instrumentation is a common urological procedure; often associated with prior ureteric stenting and postoperative urosepsis. This study aimed to explore the clinical utility of preoperative urine and intraoperative urine and ureteric stent cultures in the management of urosepsis post upper urinary tract instrumentation. Methods: Prospective study involving pre-stented patients whose upper urinary tract was instrumented at a single centre between 2017 and 2018. Five cultures were collected per patient. Patients were tracked for development of postoperative urosepsis. Results: The study included 227 patients, with a 5.7% postoperative urosepsis rate. Risk of urosepsis was significantly associated with female gender, steroid use and having a colonized preoperative urine culture, intraoperative bladder urine or stent-end culture, or kidney urine culture. Patients with a colonized intraoperative bladder urine were 11 times more likely to develop urosepsis and were colonized with the same organism isolated from urosepsis cultures for 50% of cases. Conclusions: To our knowledge this is the largest cohort study which analyses five different urinary tract cultures and the relationship with postoperative urosepsis. A positive intraoperative bladder urine culture is an independent predictor of postoperative urosepsis development and causative organism, which could guide antibiotic management for these patients. Level of Evidence 3-b

Intraoperative Cultures in Reimplantation of a Two-Stage Protocol: Only 1 vs. At Least 2 Positive Microbiological Results

Background:The main reason for using a two-stage exchange in Prosthetic Joint Infection (PJI) is that bacteria are completely eradicated in reimplantation surgery. However, reports of a positive culture in the second surgery are growing. The number of positive intraoperative cultures and their influence on final results is not well-established.Objectives:To compare epidemiological characteristics, infection recurrence and clinical evolution of patients with only onevs.at least two positive cultures based on our series of cases with positive cultures in reimplantation surgery.Material and Methods:Retrospective study of 55 patients was conducted prospectively. They were diagnosed with chronic PJI, treated with a two-stage protocol and at least three intraoperative cultures were obtained in the second stage. These cultures were negative in 28 patients. Fourteen patients showed two or more cultures with the same microorganism and they were denominated patients with positive cultures. Thirteen patients showed only one positive culture, and they were considered contaminated. Both groups of patients (positive cultures and contaminated ones) received the second cycle of oral antibiotics for 6 months. Functional results were evaluated with the Harris Hip Score (hips) or Knee Society Clinical Rating Score (KSCRS) (knees).Results:There were no significant differences between patients with positive or contaminated cultures for age (p=0.420) and sex (p=0.385). The knee was involved in 13/14 positive and in only 6/13 contaminated patients (p=0.013).Staphylococcus epidermidiswas the predominant isolate, but there were differences between positive (methicillin-resistant in 7/14 patients) and contaminated cultures (methicillin-sensitive in 6/13). There were no differences in the prevalence of polymicrobial cultures (p=0.785) or coincidence with cultures from the first stage (p=0.257). Three infection recurrences have appeared in patients with positive cultures (3/13, 21%) and none in patients with contaminated cultures. There are no differences in HSS or KSCRS when comparing final functional results between groups (p=0.411).Conclusion:The prevalence of positive cultures in reimplantation surgery is higher than expected (25%), and more frequent in women and in knee arthroplasties. The most frequently involved microorganism isStaphylococcus epidermidis, but antibiotic sensitivity varies between patients with positive cultures (methicillin-resistant) and those with contaminated cultures (methicillin-sensitive). There were no infection recurrences in patients with contaminated cultures, but those with positive cultures present a risk of over 20%.

The Different Microbial Etiology of Prosthetic Joint Infections according to Route of Acquisition and Time after Prosthesis Implantation, Including the Role of Multidrug-Resistant Organisms.

The aim of our study was to characterize the etiology of prosthetic joint infections (PJIs)—including multidrug-resistant organisms (MDRO)—by category of infection. A multicenter study of 2544 patients with PJIs was performed. We analyzed the causative microorganisms according to the Tsukayama’s scheme (early postoperative, late chronic, and acute hematogenous infections (EPI, LCI, AHI) and “positive intraoperative cultures” (PIC)). Non-hematogenous PJIs were also evaluated according to time since surgery: <1 month, 2–3 months, 4–12 months, >12 months. AHIs were mostly caused by Staphylococcus aureus (39.2%) and streptococci (30.2%). EPIs were characterized by a preponderance of virulent microorganisms (S. aureus, Gram-negative bacilli (GNB), enterococci), MDROs (24%) and polymicrobial infections (27.4%). Conversely, coagulase-negative staphylococci (CoNS) and Cutibacterium species were predominant in LCIs (54.5% and 6.1%, respectively) and PICs (57.1% and 15.1%). The percentage of MDROs isolated in EPIs was more than three times the percentage isolated in LCIs (7.8%) and more than twice the proportion found in AHI (10.9%). There was a significant decreasing linear trend over the four time intervals post-surgery for virulent microorganisms, MDROs, and polymicrobial infections, and a rising trend for CoNS, streptococci and Cutibacterium spp. The observed differences have important implications for the empirical antimicrobial treatment of PJIs.

Extended Postoperative Prophylactic Antibiotics with First-Generation Cephalosporin Do Not Reduce the Risk of Periprosthetic Joint Infection following Aseptic Revision Total Knee Arthroplasty.

Postoperative prophylactic antibiotics administered within 24 hours of primary total knee arthroplasty (TKA) have been documented to prevent periprosthetic joint infection (PJI). However, the effectiveness of this regimen is still unclear in aseptic revision TKA. The purpose of this study was to evaluate whether extended postoperative prophylactic antibiotics would reduce the PJI rate compared with the current 24-hour standard postoperative prophylactic antibiotics after aseptic revision TKA. A retrospective review of 236 patients (46 men, 190 women, 252 knees) who underwent aseptic revision TKA between 2005 and 2013 was conducted. Patients who underwent septic revision, had a positive intraoperative culture, or who had less than 2 years of follow-up were excluded. Patients were divided according to the duration of postoperative prophylactic antibiotics to standard group (76 knees, ≤ 24 hours) or extended group (176 knees, > 24 hours). PJI was determined by the Musculoskeletal Infection Society criteria. A multivariate Cox proportional hazards regression analysis was performed. The mean follow-up was 5.2 ± 2.5 years. Patients with extended postoperative prophylactic antibiotics had a lower PJI rate (1.1%) compared with standard group (3.9%), but the difference was not statistically significant (p = 0.14). Body mass index ≥ 30 kg/m2 was the only independent risk factor of PJI (adjusted hazard ratio [HR]: 9.59; 95% confidence interval [CI]: 1.07-86.04, p = 0.043). The use of extended postoperative prophylactic antibiotics was not a risk factor for PJI (adjusted HR: 0.34; 95% CI: 0.06-2.04, p = 0.238). After 10 years, the two groups had similar infection-free implant survival rate (95.9 vs. 98.9%, p = 0.15). Our findings demonstrate that extended postoperative prophylactic antibiotics did not reduce PJI rate compared with the standard group in aseptic revision TKA. A further prospective, randomized study with a standardized postoperative antibiotic protocol is necessary to address this topic. Level of evidence is prognostic Level III.

A Single Positive Tissue Culture Increases the Risk of Rerevision of Clinically Aseptic THA: A National Register Study.

The diagnostic and prognostic value of unexpected positive intraoperative cultures remains unclear in diagnosing prosthetic joint infection (PJI) in THA revisions. Therefore, we asked: (1) What is the clinical importance of bacterial growth in intraoperative tissue cultures taken during first-time revision of a clinically aseptic THA in terms of all-cause rerevision and rerevision for PJI specifically? (2) Is there a difference in outpatient antibiotic treatment patterns that is dependent on the number of positive intraoperative cultures? This register-based study included all procedures reported to the Danish Hip Arthroplasty Register (DHR) as first-time aseptic loosening revisions performed during January 2010 to May 2016. DHR data were merged with that of the Danish Microbiology Database, which contains data from all intraoperatively obtained cultures in Denmark. Both registers have been validated and have a very high degree of completeness and very few patients are missing as a result of emigration. Revisions were grouped based on the number of unexpected positive cultures growing the same bacterial genus: zero, one, or two or more cultures. We defined a positive culture as "unexpected" if it was observed after a revision THA that had been reported to the DHR as aseptic. In Denmark, cultures are routinely obtained even in revisions coded as aseptic, and in this report, 91% (2090 of 2305) of the revision THAs coded as aseptic had cultures taken. The revisions were followed until rerevision, death, or end of the 1-year followup period. The relative risk for rerevision resulting from all causes and PJI was estimated. The Danish National Prescription Registry was reviewed for outpatient antibiotic prescription within 6 weeks of revision. We included 2305 first-time aseptic revisions. Unexpected growth was found in 282 THAs (12%), of which 170 (60%) had growth in only one culture or mixed microbial growth. Coagulase-negative Staphylococcus was the dominating bacteria in 121 revisions (71%). Rerevision was performed on 163 THAs (7%) with PJI being the indication for rerevision in 43 THAs (26%). The risk of all-cause rerevision was greater among first-time revisions with one positive culture (relative risk [RR], 1.73; 95% confidence interval [CI], 1.07-2.80; p = 0.020), but not in the two or more positive group (RR, 1.52; 95% CI, 0.82-2.80; p = 0.180) when compared with the culture-negative THAs. First-time revisions with one positive culture also had a higher risk of rerevision for PJI specifically (RR, 2.63; 95% CI, 1.16-5.96; p = 0.020), but this was not the case in the two or more positive group (RR, 2.28; 95% CI, 0.81-6.43; p = 0.120). Outpatient antibiotic prescription was more frequent after revisions with two or more positive cultures compared with culture-negative revision (50 of 112 [45%] versus 353 of 2023 [17%]; p < 0.001). This was not the case in revisions with one positive culture (36 of 170 [21%] versus 353 of 2023 [17%]; p = 0.220). First-time clinically aseptic THA revisions with unexpected growth in one biopsy culture had an increased risk for rerevision, both in terms of all-cause revision and revision for PJI. The predominant bacteria in revisions with later rerevision was coagulase-negative Staphylococcus. This emphasizes that unexpected bacterial growth with common bacteria may be clinically important, even if only one of five biopsy cultures is positive. Level III, therapeutic study.

No association between positive intraoperative allograft cultures and infection rates after reconstructive knee ligament surgery

BackgroundSeveral reports of severe infections associated with allograft tissue in knee reconstructive surgery have led many surgeons to consider routine intraoperative culture of allograft tissue before implantation. Thus, the purpose of this study was to determine the prevalence of positive soft tissue allograft cultures in reconstructive knee surgery, and evaluate its association with surgical site infection. MethodsRetrospective study of 202 patients who underwent knee reconstructive ligament surgeries, including revisions, between January 2013 and July 2017. Intraoperative culture results were obtained and the report of a surgical site infection during follow-up was recorded. Patients without cultures were excluded. A priori power analysis was performed. The association between positive culture results and development of surgical site infection was evaluated using Fisher's Exact test (P < 0.05). ResultsA total of 300 allografts were implanted in 202 patients. Mean average follow-up was 32.9 ± 12.5 (range 13 to 57.9) months. Sixteen patients had positive intraoperative allograft cultures (7.9%). The most frequently isolated organism was Bacillus species (six cultures); none of these patients presented with clinical signs of infection. Nine patients developed surgical site infections and were treated with oral antibiotics, and one patient developed septic arthritis that required surgical debridement of the implanted graft; all of these patients had a negative soft tissue allograft culture. No significant association was found between a positive culture and surgical site infection (P = 0.43). ConclusionThere was no apparent association between positive intraoperative irradiated soft tissue allograft cultures and surgical site infection in reconstructive knee surgery.

Biliary drainage prior to pancreatoduodenectomy does not lead to increased infectious complications in presence of appropriate antimicrobial prophylaxis

Introduction: Preoperative biliary drainage (PBD) is a common procedure in jaundiced patients who are scheduled for pancreatoduodenectomy (PD). Unfortunately, PBD is associated with microbial colonization of the biliary system, which may lead to increased postoperative infectious complications. We aimed to evaluate the efficacy of antimicrobial prophylaxis to prevent post-operative infection-related morbidity and mortality. Methods: A single-center retrospective cohort study of all patients who underwent PD from 2000 to 2016. Patient characteristics, PBD-related information, type of antimicrobial prophylaxis, and data on intra-operative bile cultures were collected. The primary outcome was rate of postoperative complications according to international guidelines, stratified by bile culture outcome. Results: A total of 413 patients underwent PD for benign or malignant disease. In 227 patients (55%) intra-operative bile cultures were performed. Of these, 184 patients (81%) underwent PBD. Almost all patients received antimicrobial prophylaxis for PD, primarily cefazolin and metronidazole. In the PBD group, 156 patients (86%) had bacterial, 79 patients (43%) had fungal, and 77 patients (41.8%) had polymicrobial bile cultures, compared to 18 patients (42%; P < 0.001), 7 patients (16%; P = 0.001), and 7 patients (16%; P = 0.002) in the non-PBD group, respectively. Post-operative complication rates and severity were similar among the PBD and non-PBD groups. Conclusion: Despite a significantly increased rate of positive intra-operative bile cultures during PD in patient who previously underwent PDB, appropriate antimicrobial prophylaxis seems sufficient to prevent increased infectious complications.

Culture positivity in primary total shoulder arthroplasty

The clinical significance of positive cultures in shoulder surgery remains unclear. This study determined the rate and characteristics of positive intraoperative cultures in a cohort of patients undergoing primary shoulder arthroplasty. From February 2015 to March 2016, 94 patients, without prior surgery, underwent primary shoulder arthroplasty. Before surgery, all shoulders were prospectively enrolled and consented to obtain standardized intraoperative cultures. All patients received standard preoperative antibiotic prophylaxis. Standardized fluid and tissue locations were sampled and sent for aerobic and anaerobic cultures and held for 13 days. Patients and surgeon were blinded to the culture results. Average age at surgery was 70.5 years (range, 50-91 years), and 41 patients (47%) were male. At least 1 positive culture was found in 33 shoulders (38%), with 17 patients (19%) having ≥2 positive cultures. Cutibacterium (formerly Propionibacterium) acnes was the most common organism (67%), followed by coagulase-negative Staphylococcus (21%), Staphylococcus aureus (3%), and other organisms (18%). The rate of positive culture was higher in men (51%) than in women (26%, P = .016). Cutibacterium acnes was more common in men with positive cultures (95% vs. 17%, P < .001) and coagulase-negative Staphylococcus and Staphylococcus epidermidis were more common in women with positive cultures (42% vs. 10%, P = .071). Positive deep tissue cultures develop in a high percentage of patients undergoing primary shoulder arthroplasty despite antibiotic prophylaxis. The long-term clinical implication of this finding requires further study, especially with regard to the risk of late failures of shoulder arthroplasty.