Bacterial resistance trends among intraoperative bone culture of chronic osteomyelitis in an affiliated hospital of South China for twelve years

Is there a role for suppression of infection in managing fracture-related infection following intra-medullary nailing?

BACKGROUND

The management of fracture-related infection has undergone radical progress following the development of international guidelines. However, there is limited consideration to the realities of healthcare in low-resource environments due to a lack of available evidence in the literature from these settings. Initial antimicrobial suppression to support fracture union is frequently used in low- and middle-income countries despite the lack of published clinical evidence to support its practice. This study aimed to evaluate the outcomes following initial antimicrobial suppression to support fracture union in the management of fracture-related infection.

METHODS

A retrospective review of consecutive patients treated with initial antimicrobial suppression to support fracture healing followed by definitive eradication surgery to manage fracture-related infections following intramedullary fixation was performed. Indications for this approach were; a soft tissue envelope not requiring reconstructive surgery, radiographic evidence of stable fixation with adequate alignment, and progression towards fracture union.

RESULTS

This approach was associated with successful treatment in 51/55 (93 %) patients. Fracture union was achieved in 52/55 (95 %) patients with antimicrobial suppression alone. Remission of infection was achieved in 54/55 (98 %) patients following definitive infection eradication surgery. Following antibiotic suppression, 6/46 (13 %) pathogens isolated from intra-operative samples demonstrated multi-drug resistance.

CONCLUSION

Initial antimicrobial suppression to support fracture healing followed by definitive infection eradication surgery was associated with successful treatment in 93 % of patients. The likelihood of remission of infection increases when eradication surgery is performed in a healed bone. This approach was not associated with an increased risk of developing multi-drug-resistant infections compared to contemporary bone infection cohorts in the published literature.

LEVEL OF EVIDENCE

IV.

Optimizing diagnosis and surgical decisions for chronic osteomyelitis through radiomics in the precision medicine era

Introduction: Chronic osteomyelitis is a complex clinical condition that is associated with a high recurrence rate. Traditional surgical interventions often face challenges in achieving a balance between thorough debridement and managing resultant bone defects. Radiomics is an emerging technique that extracts quantitative features from medical images to reveal pathological information imperceptible to the naked eye. This study aims to investigate the potential of radiomics in optimizing osteomyelitis diagnosis and surgical treatment. Methods: Magnetic resonance imaging (MRI) scans of 93 suspected osteomyelitis patients were analyzed. Radiomics features were extracted from the original lesion region of interest (ROI) and an expanded ROI delineated by enlarging the original by 5 mm. Feature selection was performed and support vector machine (SVM) models were developed using the two ROI datasets. To assess the diagnostic efficacy of the established models, we conducted receiver operating characteristic (ROC) curve analysis, employing histopathological results as the reference standard. The model's performance was evaluated by calculating the area under the curve (AUC), sensitivity, specificity, and accuracy. Discrepancies in the ROC between the two models were evaluated using the DeLong method. All statistical analyses were carried out using Python, and a significance threshold of p < 0.05 was employed to determine statistical significance. Results and Discussion: A total of 1,037 radiomics features were extracted from each ROI. The expanded ROI model achieved significantly higher accuracy (0.894 vs. 0.821), sensitivity (0.947 vs. 0.857), specificity (0.842 vs. 0.785) and AUC (0.920 vs. 0.859) than the original ROI model. Key discriminative features included shape metrics and wavelet-filtered texture features. Radiomics analysis of MRI exhibits promising clinical translational potential in enhancing the diagnosis of chronic osteomyelitis by accurately delineating lesions and identifying surgical margins. The inclusion of an expanded ROI that encompasses perilesional tissue significantly improves diagnostic performance compared to solely focusing on the lesions. This study provides clinicians with a more precise and effective tool for diagnosis and surgical decision-making, ultimately leading to improved outcomes in this patient population.

Causative Pathogens Do Not Differ between Early, Delayed or Late Fracture-Related Infections

Fracture-related infections (FRIs) are classically considered to be early (0−2 weeks), delayed (3−10 weeks) or late (>10 weeks) based on hypothesized differences in causative pathogens and biofilm formation. Treatment strategies often reflect this classification, with debridement, antimicrobial therapy and implant retention (DAIR) preferentially reserved for early FRI. This study examined pathogens isolated from FRI to confirm or refute these hypothesized differences in causative pathogens over time. Cases of FRI managed surgically at three centres between 2015−2019 and followed up for at least one year were included. Data were analysed regarding patient demographics, time from injury and pathogens isolated. Patients who underwent DAIR were also analysed separately. In total, 433 FRIs were studied, including 51 early cases (median time from injury of 2 weeks, interquartile range (IQR) of 1−2 weeks), 82 delayed cases (median time from injury of 5 weeks, IQR of 4−8 weeks) and 300 late cases (median time from injury of 112 weeks, IQR of 40−737 weeks). The type of infection was associated with time since injury; early or delayed FRI are most likely to be polymicrobial, whereas late FRIs are more likely to be culture-negative, or monomicrobial. Staphylococcus aureus was the most commonly isolated pathogen at all time points; however, we found no evidence that the type of pathogens isolated in early, delayed or late infections were different (p = 0.2). More specifically, we found no evidence for more virulent pathogens (S. aureus, Gram-negative aerobic bacilli) in early infections and less virulent pathogens (such as coagulase negative staphylococci) in late infections. In summary, decisions on FRI treatment should not assume microbiological differences related to time since injury. From a microbiological perspective, the relevance of classifying FRI by time since injury remains unclear.

Epidemiology and Drug Resistance of Fracture-Related Infection of the Long Bones of the Extremities: A Retrospective Study at the Largest Trauma Center in Southwest China

Objective

To describe the demographic characteristics, risk factors, and bacterial resistance of fracture-related infection (FRI) of the long bones of the extremities.

Materials and Methods

This single-center study retrospectively evaluated patients with FRI of the long bones of the extremities at West China Hospital between January 2012 and December 2017, and analyzed the demographic characteristics, risk factors, distribution of pathogenic bacteria, and bacterial drug resistance.

Results

Among 9,900 patients, 535 patients (5.4%) were diagnosed with FRI. The most common site of FRI was tibiofibular (298, 55.7%), with 424 cases (79.2%) of open fractures, and 282 cases (52.7%) due to traffic injuries. The 41–50 years age group had the highest incidence of FRI with 157 (29.3%) cases. Overall, 546 strains of 52 types of bacteria were detected in FRI patients, with 105 strains of multidrug-resistant (MDR) bacteria. Methicillin-resistant Staphylococcus aureus (48, 8.8%) and extended-spectrum-β-lactamase Escherichia coli (32, 5.8%) accounted for the largest proportion. Multivariate logistic regression analysis showed that sex (odds ratio [OR] 1.813; 95% confidence interval [CI], 1.071∼3.070; P = 0.027) and fracture type (OR 3.128; 95% CI, 1.683∼5.815; P < 0.001) were independent risk factors for monomicrobial infection (MI). Female sex (OR 4.190; 95% CI, 1.212∼14.486; P = 0.024) was an independent risk factor for polymicrobial infection (PI).

Conclusion

This study clarified the infection rates, changes in the bacterial spectrum, and drug resistance characteristics, and risk factors of FRI of the long bones of the extremities in the largest trauma center in southwest China.

Antimicrobial Photodynamic Therapy Involving a Novel Photosensitizer Combined With an Antibiotic in the Treatment of Rabbit Tibial Osteomyelitis Caused by Drug-Resistant Bacteria

Osteomyelitis is deep tissue inflammation caused by bacterial infection. If such an infection persists, it can lead to dissolution and necrosis of the bone tissue. As a result of the extensive use of antibiotics, drug-resistant bacteria are an increasingly common cause of osteomyelitis, limiting the treatment options available to surgeons. Photodynamic antibacterial chemotherapy has attracted increasing attention as a potential alternative treatment. Its advantages are a broad antibacterial spectrum, lack of drug resistance, and lack of toxic side effects. In this study, we explored the impact of the new photosensitizer LD4 in photodynamic antimicrobial chemotherapy (PACT), both alone and in combination with an antibiotic, on osteomyelitis. A rabbit tibial osteomyelitis model was employed and microbiological, histological, and radiological studies were performed. New Zealand white rabbits (n = 36) were randomly divided into a control group, antibiotic group, PACT group and PACT + antibiotic group for treatment. In microbiological analysis, a reduction in bacterial numbers of more than 99.9% was recorded in the PACT group and the PACT + antibiotic group 5 weeks after treatment (p < 0.01). In histological analysis, repair of the damaged bone tissue was observed in the PACT group, and bone repair in the PACT + antibiotic group was even more significant. In radiological analysis, the X-ray Norden score showed that the severity of bone tissue defects or destruction followed the pattern: PACT + antibiotic group < PACT group < antibiotic group < control group.

Tailored therapeutic release from polycaprolactone-silica hybrids for the treatment of osteomyelitis: antibiotic rifampicin and osteogenic silicates

The treatment of osteomyelitis, a destructive inflammatory process caused by bacterial infections to bone tissue, is one of the most critical challenges of orthopedics and bone regenerative medicine. The standard treatment consists of intense antibiotic therapies combined with tissue surgical debridement and the application of a bone defect filler material. Unfortunately, commercially available candidates, such as gentamicin-impregnated polymethylmethacrylate cements, possess very poor pharmacokinetics (i.e., 24 hours burst release) and little to no regenerative potential. Fostered by the intrinsic limitations associated with conventional treatments, alternative osteostimulative biomaterials with local drug delivery have recently started to emerge. In this study, we propose the use of a polycaprolactone-silica sol-gel hybrid material as carrier for the delivery of rifampicin, an RNA-polymerase blocker often used to treat bone infections, and of osteostimulative silicate ions. The release of therapeutic agents from the material is dual, offering two separate and simultaneous effects, and decoupled, meaning that the kinetics of rifampicin and silicate releases are independent from each other. A series of hybrid formulations with increasing amounts of rifampicin was prepared. The antibiotic loading efficacy, as well as the release profiles of rifampicin and silicates were measured. The characterization of cell viability and differentiation of rat primary osteoblasts and antibacterial performance were also performed. Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli were selected due to their high occurrence in bone infections. Results confirmed that rifampicin can be successfully loaded within the hybrids without significant degradation and that it is possible to tailor the antibiotic release according to need. Once in a physiological environment, the rapid release of silicates was associated with optimal cell proliferation and the overexpression of osteoblastic differentiation. Simultaneously, rifampicin is delivered over the course of several weeks with significant inhibition of all tested strains. In particular, the materials caused a growth reduction of 7-10 orders of magnitude in Staphylococcus aureus, the major strain responsible for osteomyelitis worldwide. Our data strongly suggest that PCL/silica hybrids are a very promising candidate to develop bone fillers with superior biological performance compared to currently available options. Thanks to their unique synthesis route and their dual tailored release they can promote bone regeneration while reducing the risk of infection for several weeks upon implantation.

Native bone and joint infections caused by extended-spectrum β-lactamase-producing Enterobacterales: experience of a reference centre in the Greater Paris area

Antibiotic treatment of native osteomyelitis caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) is a challenge. Limited epidemiological and outcome data are available. This retrospective cohort study included osteomyelitis patients with ESBL-PE infections treated in a reference centre for bone and joint infections (BJIs) between 2011-2019. Twenty-nine patients with native BJI (mean age, 44.4 ± 15.7 years) were analysed. Fifteen cases were paraplegic patients with ischial pressure sores breaching the hip capsule. Other cases included eight other hip infections, four tibial infections and two foot infections. Infections were mostly polymicrobial (n = 23; 79.3%), including Staphylococcus aureus (n = 13; 8 methicillin-resistant). Klebsiella pneumoniae (n = 13) was the most frequent ESBL-producing species identified, followed by Escherichia coli (n = 10), including 3 E. coli/K. pneumoniae co-infections, and Enterobacter spp. (n = 9). ESBL-PE were rarely susceptible to fluoroquinolones (n = 4; 13.8%). Most therapies were based on carbapenems (n = 22) and combination therapies (n = 19). The median duration of treatment was 41 (5-60) days. Primary control of the infection was achieved in 62.1% (18/29) of cases and up to 86.2% after second look surgeries, after a median follow-up of 6 (1-36) months. Infection with ESBL-producing K. pneumoniae was associated with failure (P = 0.001), whereas age, infection location, prior colonisation and antimicrobial therapy were not found to be predictors of outcome. ESBL-PE native BJIs are often polymicrobial and fluoroquinolone-resistant infections caused by K. pneumoniae, highlighting the need for expert centres with pluridisciplinary meetings with experienced surgeons.

Epidemiology and microbiology of fracture-related infection: a multicenter study in Northeast China

Objective

This study aimed to explore the epidemiological and microbiological characteristics of fracture-related infection (FRI), analyze the drug resistance characteristics of major pathogens, and provide timely and relatively complete clinical and microbiological data for antimicrobial treatment of FRI.

Methods

The clinical and microbiological data of patients with FRI from January 1, 2011, to December 31, 2020, were collected from three tertiary hospitals in Northeast China. The automatic microbial analysis system was used for strain identification and drug susceptibility testing, and the drug susceptibility results were determined in accordance with the latest Clinical and Laboratory Standards Institute (CLSI) criteria (as applicable each year).

Results

A total of 744 patients with FRI were enrolled. The incidence of FRI was about 1.5%, and 81.7% were male patients, with an average age of 48.98 ± 16.01 years. Open fractures accounted for 64.8%. Motor crush (32.8%) and falling (29.8%) were the main causes of injuries. The common sites of infection were the tibia and fibula (47.6%), femur (11.8%), foot (11.8%), and hand (11.6%). A total of 566 pathogenic bacteria were cultured in 378 patients with positive bacterial cultures, of which 53.0% were Gram-positive bacteria and 47.0% were Gram-negative bacteria. The most common pathogen at all sites of infection is Staphylococcus aureus. Staphylococcus aureus had a high resistance rate to penicillin (PEN), erythromycin (ERY), and clindamycin (CLI), exceeding 50%. Methicillin-resistant Staphylococcus aureus (MRSA) was more than 80% resistant to CLI and ERY.

Conclusions

The incidence of FRI in Northeast China was at a low level among major medical centers nationwide. Staphylococcus aureus was still the main pathogen causing bone infections, and the proportion of MRSA was lower than reported abroad, but we have observed an increase in the proportion of infections. Enterobacteriaceae have a higher resistance rate to third-generation cephalosporins and quinolones. For Enterobacteriaceae, other sensitive treatment drugs should be selected clinically.

Bacillus subtilis revives conventional antibiotics against Staphylococcus aureus osteomyelitis

As treatment of Staphylococcus aureus (S. aureus) osteomyelitis is often hindered by the development of antibiotic tolerance, novel antibacterial therapeutics are required. Here we found that the cell-free supernatant of Bacillus subtilis (B. subtilis CFS) killed planktonic and biofilm S. aureus, and increased S. aureus susceptibility to penicillin and gentamicin as well. Further study showed that B. subtilis CFS suppressed the expression of the genes involved in adhesive molecules (Cna and ClfA), virulence factor Hla, quorum sensing (argA, argB and RNAIII) and biofilm formation (Ica and sarA) in S. aureus. Additionally, our data showed that B. subtilis CFS changed the membrane components and increased membrane permeabilization of S. aureus. Finally, we demonstrated that B. subtilis CFS increased considerably the susceptibility of S. aureus to penicillin and effectively reduced S. aureus burdens in a mouse model of implant-associated osteomyelitis. These findings support that B. subtilis CFS may be a potential resistance-modifying agent for β-lactam antibiotics against S. aureus.

Culture Concordance in Different Sections of the Metatarsal Head: Interpretations of Microbiological Results

Microbiological cultures of per-wound bone biopsies have shown a lack of correlation and a high rate of false-negative results when compared with bone biopsy cultures in diabetic foot osteomyelitis. The selection of samples from the area of active osteomyelitis, which contains a complete census of the microorganisms responsible for the infection, is essential to properly guide antimicrobial treatment. We aimed to comparatively evaluate the quantitative and qualitative cultures taken from different areas, in metatarsal heads resected for osteomyelitis. For this purpose, we consecutively selected 13 metatarsal heads from 12 outpatients with plantar ulcers admitted to our diabetic foot unit. Metatarsal heads were divided transversally into 3 portions: plantar (A), central (B), and dorsal (C), and the 39 resulting samples were cultured. Qualitative and quantitative microbiological analysis was performed, and the isolated species and bacterial load, total and species specific, were compared between the 3 metatarsal bone segments. The primary outcome of the study was the bacterial diversity detected in the different bone sections. Cultures were positive in 12 of the 13 included metatarsal heads (92%). A total of 34 organisms were isolated from all specimens. Ten of the 12 cultures (83%) were polymicrobial. Ten of the 13 metatarsal heads (77%) had identical microbiological results in each of the 3 bone sections. The largest number of microorganisms was found in the central section. The overall concordance between sections was 91%. The predominant microorganisms were coagulase-negative staphylococci (41%). Statistical differences were not found in the bioburden between sections (range 3.25-3.41 log₁₀ colony-forming unit/g for all sections; P = .511). The results of our study suggest that microorganisms exhibit a high tendency to spread along the metatarsal bone and that the degree of progression along the bone is species dependent. The central portions of metatarsal bones tend to accumulate a higher diversity of species. Thus, we recommend this area of bone for targeted biopsy in patients with suspected osteomyelitis.

MRI Manifestations and Diagnostic Value of Chronic Osteomyelitis

If chronic osteomyelitis is not treated promptly and thoroughly, the wound will not heal for a long time, and the affected limb will be dysfunctional or disabled. In severe cases, it may even require amputation. In this article, a total of 50 patients with chronic osteomyelitis who meet the inclusion criteria were selected from January 2019 to March 2020 and were divided into two groups based on patient compliance, namely, a treatment group and a control group. The results of this group of studies showed that osteomyelitis is mostly manifested as limited diffusion, showing high signal on DWI, and ADC value is significantly higher than that of normal bone area. The normal bone area did not show obvious focal abnormal signals on the conventional MRI image. The ADC value of the measured patient's osteomyelitis area was compared with the ADC value of the normal bone area. The ADC value was significantly higher than that of the normal bone area, and the difference was statistically significant. Studies have shown that membrane induction technology is superior to the bone handling group in terms of limb function scores and results satisfaction in the treatment of chronic osteomyelitis bone defects. Membrane induction technology has a low complication rate, a small number of X-ray examinations, a short healing time, and a high functional score. However, bone handling technology has a long treatment process, long fixation time and healing time, nail channel infection, joint stiffness, nerve damage, and many other complications.

Enterobacter cloacae infection of the shoulder in a 52-year-old woman without apparent predisposing risk factor: a case report and literature review

Background

Enterobacter cloacae (E. cloacae) is one of the commensal flora in the human intestinal tract and a prevalent nosocomial pathogen, which rarely causes infectious osteoarthritis in immunocompetent patients without recent trauma or surgery. Here, we report the first case of septic monoarthritis of the shoulder caused by E. cloacae in an immunocompetent patient.

Case presentation

A 52-year-old female with a 6-year history of right shoulder pain was referred to our emergency department due to fever, acute severe shoulder pain, and swelling. Blood test showed elevated inflammatory markers. The patient denied any recent invasive surgical procedure and trauma. She was misdiagnosed with a frozen shoulder, and the anti-inflammatory painkiller celecoxib for symptomatic treatment was ineffective. Magnetic resonance imaging (MRI) showed a shoulder joint abscess and supraspinatus tendon tear. The joint aspirate culture showed E. cloacae. After late diagnosis, she was treated with levofloxacin and underwent surgical debridement and irrigation. Her follow-up data revealed that she did not suffer from shoulder swelling and severe pain.

Conclusion

This is a rare case of E. cloacae infected arthritis of the shoulder in an immunocompetent patient with a rotator cuff tear, indicating that even if the symptoms and age of the patients match the characteristics of frozen shoulder, the possibility of septic arthritis should be considered in the presence of fever and increasing inflammatory markers. The cases of our literature review suggest that the patients subjected to invasive procedure may develop a subsequent E. cloacae osteoarticular infection, regardless of being asymptomatic after the procedure.

Effective and Rapid Microbial Identification in Pediatric Osteoarticular Infections Using Blood Culture Bottles

BACKGROUND

The detection and identification of pathogenic microorganisms are essential for the treatment of osteoarticular infection. However, obtaining a sufficient amount of specimen from pediatric patients is often difficult. Herein, we aimed to demonstrate the effectiveness of the blood culture bottle (BCB) system in pediatric osteoarticular infections. We hypothesized that our BCB culture method is superior to the conventional swab and tissue culture methods in terms of required specimen size, incubation time, and microbial identification rate.

METHODS

We analyzed the prospectively collected data of pediatric patients who underwent surgical treatment for osteoarticular infections between August 2016 and October 2019. Four needles were dipped in the infected fluid or tissue during the surgical procedure as soon as the infected area was exposed and were used to inoculate 2 aerobic pediatric BCBs and 2 anaerobic general BCBs. We also collected 2 conventional swab samples and 2 tissue samples from the identical area. The microbial identification rate and the time required for identification were compared between BCB, swab, and tissue cultures.

RESULTS

Forty patients constituted the study group; 13 patients had osteomyelitis, 17 patients had septic arthritis, and 10 patients had both. Of these 40 patients, the microbial identification rate was higher with BCB cultures (27 [68%]) than with swab cultures (18 [45%]; p = 0.004) or tissue cultures (15 [38%]; p < 0.001). Nine samples (9 patients [23%]) were only positive in the BCB culture. Positive microbial growth was not detected with conventional culture methods when microorganisms did not grow on the BCB culture. Compared with swab culture (4.3 ± 1.1 days; p < 0.001) or tissue culture (4.4 ± 1.1 days; p < 0.001), the BCB culture reduced the time required for microbial identification (3.5 ± 0.9 days).

CONCLUSIONS

In pediatric osteoarticular infections, the BCB culture system improved the microbial identification rate, reduced the time to identification, and permitted a smaller-volume specimen, compared with traditional culture systems.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Trends in bacterial resistance among perioperative infections in patients with primary ovarian cancer: A retrospective 20-year study at an affiliated hospital in South China

Background

We aimed to analyze the epidemiological and drug-resistance trends among bacterial cultures from perioperative infections in patients with primary ovarian cancer.

Methods

Medical and bacteriological records for patients with ovarian cancer patients who developed perioperative infections after primary cytoreductive surgery from 1999 to 2018 were reviewed retrospectively.

Results

The incidence of perioperative infections and the culture-positive percentage among patients in the first 10 years were 20.2% and 29.3%, respectively, and the equivalent rates in the second 10 years were 18.0% and 33.5%. The most commonly isolated pathogens in both year-groups were Escherichia coli and Enterococcus spp., but the respective percentages differed between the groups. Some strains of Staphylococcus aureus and Enterococcus spp. in the second 10-year group were resistant to linezolid and vancomycin, and ciprofloxacin resistance among Gram-negative bacteria isolates also increased in this group. However, resistance of Gram-negative bacteria to imipenem and meropenem was low among in both groups.

Conclusion

The pathogen distribution in perioperative infections in patients with primary ovarian cancer undergoing cytoreductive changed slightly from 1999 to 2018, and the antibiotic resistance of the main isolated pathogens increased. These results indicate the importance of periodic bacterial surveillance of surgical infections in these patients.

Analysis of Urinary Pathogen Cultures and Drug Sensitivity in Patients with Urinary Stones for Five Consecutive Years in Xiangya Hospital, China

Objective

To analyze pathogen distribution and drug sensitivity in patients with urinary calculi and thereby gain insight into the most appropriate antibacterial drugs for perioperative therapy.

Materials and Methods

From January 2014 to December 2018, the results of mid-stream urine pathogen culture and drug sensitivity tests were evaluated retrospectively for 353 patients with urinary calculi. SPSS software version 23.0 was used to analyze the data.

Results

A total of 353 strains of pathogens were isolated from urine culture. Among these, 278 (79%) strains belonged to the top 10 most frequently isolated pathogens, comprising 209 (75.2%) Gram-negative bacilli and 69 (24.8%) Gram-positive cocci. Escherichia coli was the most frequently isolated pathogen overall and the most frequently isolated Gram-negative bacillus, and Enterococcus faecalis was the most frequently isolated Gram-positive coccus. Drug sensitivity levels were effectively unchanged for less commonly used drugs, whereas drug resistance rates remained high for commonly used drugs such as ampicillin trihydrate, ampicillin/sulbactam, cefazolin, ceftriaxone, aztreonam, levofloxacin and ciprofloxacin.

Conclusion

E. coli and E. faecalis remain the most common Gram-negative bacillus and Gram-positive coccus uropathogens, respectively, in patients with urinary calculi. Mid-stream urine pathogen culture and drug sensitivity tests should be used to select appropriate antibacterial drugs before treatment, particularly for perioperative patients with urinary calculi.

Extirpative Cultures Reveal Infectious Pubic Bone Osteomyelitis in Prostate Cancer Survivors With Urinary-Pubic Symphysis Fistulae (UPF)

OBJECTIVE

To examine the infectious features of patients with urinary pubic symphysis fistula (UPF) and their association with osteomyelitis.

METHODS

We conducted a review of our quality improvement database for 36 patients with UPF undergoing bone resection and extirpative surgery from October 2012 to January 2019. An assessment of bone and urine cultures was carried out along with surgical, radiologic, and demographic data. We analyzed descriptive statistics and used Fisher Exact Tests and unpaired Welch t tests to assess for associations with positive bone cultures.

RESULTS

In our cohort, 33 patients (91.7%) had positive bone cultures with the 3 most common organisms being candida (22.0%), enterococcus (18.0%), and pseudomonas (10.0%). There was a correlation between positive preoperative urine culture and positive bone culture (P <.01), with 63.0% of those with positive urine cultures growing the same organism on bone culture.

CONCLUSION

In this series, 91.7% of patients undergoing extirpative surgery for UPF at our institution have positive bone cultures at time of pubic bone debridement. Additionally, we demonstrate a statistically significant correlation between positive urine cultures and positive bone cultures in these patients. This supports the need for a multidisciplinary approach including infectious disease, orthopedic surgery and reconstructive urology in order to address this complex clinical condition.

Microbiological profile of chronic osteomyelitis with special reference to anaerobic osteomyelitis in a tertiary care hospital of coastal Karnataka

Chronic osteomyelitis is a relapsing, persistent, low-grade inflammation of bone caused by various infectious agents. The present study, conducted over a two-year period, on specimens received from cases of chronic osteomyelitis was, to determine the frequency of isolation of aerobic and anaerobic bacteria and to analyse their antimicrobial susceptibility pattern. Specimens were processed for Gram stain, aerobic and anaerobic culture, and were identified according to standard techniques. Significant growth was observed in 102/204 specimens, in which aerobic growth was observed in 62 (60.8%) and anaerobic in 40 (39.2%). Resistance to metronidazole and clindamycin was observed in 6.7% and 30% of the anaerobic isolates, respectively. None of these were resistant to meropenem. A significant proportion of anaerobic isolates were found to be resistant to commonly used empirical drugs, such as clindamycin, thus necessitating a need for routine anaerobic susceptibility testing.