1150. Pediatric Osteoarticular Infections Caused by Mycobacteria Tuberculosis Complex: A Twenty-Six Year Review of Cases in San Diego, California

Abstract Background Osteoarticular infections (OAI) account for 10-20% of extrapulmonary Mycobacteria tuberculosis (MTB) complex infections in children. Given the rarity of MTB OAI, the epidemiology, disease manifestations, and treatment are poorly characterized. We describe 21 children treated for MTB complex OAI over a 26-year period at a tertiary pediatric center in southern California. Methods We conducted a retrospective review of children diagnosed with MTB complex OAI and cared for between 31 Dec 1992 to 31 Dec 2018 at a single tertiary care pediatric hospital with close proximity to the United States-Mexico border. Results We identified 21 children with MTB complex OAI during the study period (Table 1). Concurrent pulmonary disease (4.8%), meningitis (9.5%), and intra-abdominal involvement (14.3%) were all observed. MTB complex was identified by culture from operative samples in 15/21 children (71.4%); 8/15 (51.3%) cultures were positive for Mycobacterium bovis. Of the eight cases of vertebral OAI (the most common site), one was culture-positive for M. bovis. Open bone biopsy was the most common procedure for procurement of a tissue sample and had the highest culture yield (Table 2). The median duration of antimicrobial therapy was 52 weeks (IQR 52-58). Successful completion of therapy was documented in 15 children (71.4%). Seven children (33.3%) experienced long term sequelae related to their infection. Table 1. Twenty-one children with Mycobacteria tuberculosis complex osteoarticular infections. Table 2. Surgical sample type and percent positivity. Conclusion Among the 21 children with MTB complex OAI assessed, 8 of 15 (53.3%) children with a positive tissue culture had M. bovis (intrinsically resistant to pyrazinamide), representing a higher percentage than in previous reports and potentially reflecting its presence in unpasteurized dairy products in the California-Baja region. Local epidemiological trends in endemic MTB complex species should be considered when evaluating and managing MTB complex OAI. Bone biopsy produced the highest culture yield in this study. Given the rarity of this disease, multicenter collaborative studies are needed to improve our understanding of the presentation and management of pediatric MTB complex OAI. Disclosures Vanessa Raabe, MD, MSc, Pfizer (Scientific Research Study Investigator, Other Financial or Material Support, Editorial support)Sanofi (Scientific Research Study Investigator)

Background. Although a bacterial multiplex polymerase chain reaction (mPCR) test should be performed selectively in patients with gastrointestinal symptoms consistent with bacterial enteritis, its usefulness has been evaluated upon stool samples as requested by clinicians, without considering the patients' gastrointestinal symptoms or clinical diagnoses. This study aimed to determine the subjects to bacterial mPCR testing and to interpret the mPCR test results with considering patients' clinical symptoms and diagnoses.
Methods. Medical records of 710 pediatric patients for whom a bacterial mPCR test was performed were retrospectively reviewed. Clinical characteristics and mPCR test results were compared between patients with positive mPCR test results (n = 199) and those with negative mPCR test results (n = 511) and between patients in whom inflammatory pathogens (Campylobacter spp. and Salmonella spp.) were identified (n = 95) and those in whom toxigenic pathogens (Clostridium spp.) were identified (n = 70).

Results.
A positive mPCR test result was significantly associated with an older age (p < 0.001), diagnosis of acute gastroenteritis (p = 0.021), presence of hematochezia (p < 0.001), and absence of cough (p = 0.004). The diagnosis of acute gastroenteritis (p = 0.003), presence of fever (p = 0.027) and diarrhea (p = 0.043), and a higher C-reactive protein level (p = 0.025) were significantly associated with the identification of inflammatory pathogens rather than toxigenic pathogens in patients with positive mPCR test results.
Conclusion. Bacterial mPCR testing should be performed selectively based on patients' clinical symptoms and diagnoses, and its results should be interpreted with considering identified pathogens.
Disclosures. Background. Osteoarticular infections (OAI) account for 10-20% of extrapulmonary Mycobacteria tuberculosis (MTB) complex infections in children. Given the rarity of MTB OAI, the epidemiology, disease manifestations, and treatment are poorly characterized. We describe 21 children treated for MTB complex OAI over a 26-year period at a tertiary pediatric center in southern California.
Methods. We conducted a retrospective review of children diagnosed with MTB complex OAI and cared for between 31 Dec 1992 to 31 Dec 2018 at a single tertiary care pediatric hospital with close proximity to the United States-Mexico border.
Results. We identified 21 children with MTB complex OAI during the study period (Table 1). Concurrent pulmonary disease (4.8%), meningitis (9.5%), and intra-abdominal involvement (14.3%) were all observed. MTB complex was identified by culture from operative samples in 15/21 children (71.4%); 8/15 (51.3%) cultures were positive for Mycobacterium bovis. Of the eight cases of vertebral OAI (the most common site), one was culture-positive for M. bovis. Open bone biopsy was the most common procedure for procurement of a tissue sample and had the highest culture yield ( Table 2). The median duration of antimicrobial therapy was 52 weeks (IQR 52-58). Successful completion of therapy was documented in 15 children (71.4%). Seven children (33.3%) experienced long term sequelae related to their infection. pyrazinamide), representing a higher percentage than in previous reports and potentially reflecting its presence in unpasteurized dairy products in the California-Baja region. Local epidemiological trends in endemic MTB complex species should be considered when evaluating and managing MTB complex OAI. Bone biopsy produced the highest culture yield in this study. Given the rarity of this disease, multicenter collaborative studies are needed to improve our understanding of the presentation and management of pediatric MTB complex OAI.
Disclosures Background. Persistent Staphylococcus aureus bacteremia (pSAB) is a poorly defined entity, but associated with significant morbidity and mortality in children. We aim to better describe the epidemiological features of this clinical entity.
Methods. We performed a retrospective case series analysis of pediatric patients with pSAB at a single center children's hospital using electronic medical data from 2016 -2020. Bacterial persistence was defined as culture growth > 72 hours after first blood culture.
Results. Twenty-two patients with pSAB were included in the analysis. Sources of persistent infection were endovascular infection (n=11, 50%), osteoarticular infection (n=6, 27%,), isolated central line associated blood stream (n=4, 18%), isolated skin and soft tissue infection (n=2, 9%), and no known primary infectious site (n=1). Methicillin resistance occurred in 41% (n=9) of cases of pSAB. Total duration of therapy varied, with a median of 4 weeks from negative cultures (range of 2 -8 weeks). Total days of positive cultures in pSAB were not significantly associated with methicillin susceptibility of the bacterial isolate, use of double gram-positive coverage, nor presence of a central venous catheter. Use of double gram-positive coverage occurred in 50% of cases with a mean duration of therapy of 11 days, most frequently in cases of septic thrombophlebitis (Table 1). Rifampin and gentamicin were the most commonly used agents.

Table 1. Clinical Characteristics of Children Treated with Double Gram-Positive Coverage
Conclusion. Children presenting with persistent S. aureus bacteremia present with a heterogenous group of underlying conditions and epidemiological features. While pediatric recommendations for double gram-positive coverage for synergy have not been established, their use for pSAB is common, especially in endovascular infections where culture persistence is often an expected outcome. Further research should examine risk factors for pSAB and define optimal treatment modalities and duration.
Disclosures. Background. Studies of pediatric neck infections demonstrate an increase in methicillin resistant Staphylococcus aureus (MRSA), and predominance of Staphylococcus aureus (S. aureus) in infants, and commonly polymicrobial infections. Thus, some providers treat acute neck infections with empiric broad spectrum antibiotics, often with two drugs. Our institution often uses clindamycin plus ampicillin-sulbactam as empiric therapy for hospitalized children with acute neck infection. We aimed to identify the microbiology of acute neck abscesses at our institution to determine if stratifying by age and abscess location would allow for single agent therapy.

Methods.
Diagnosis codes identified patients hospitalized with acute neck infections. Cases with underlying malignancy, cervicofacial malformations, or lymphatic malformations were excluded. Patients with surgical cultures were categorized into two groups based on anatomic location of infection: medial (retropharyngeal, parapharyngeal, and peritonsillar), lateral (other locations), or both. Within each group, causative pathogen(s) were explored and further categorized by age (infants: < 1 year old; non-infants: ≥1 year old).
Results. 412 patients were hospitalized for acute neck infection of which 132 had surgical cultures. 110 had growth of one or more pathogens (20 infants, 90 non-infants). 53 infections were located medially, 54 laterally, and 3 had both locations involved. S. aureus was most commonly identified, with lateral infections accounting for the majority (Table 1). 40/44 S. aureus isolates were susceptible to clindamycin. Among medial infections, Streptococcus Anginosus and Group A Streptococcus were most common followed by S. aureus (Table 1). 17/20 (85%) positive cultures in infants grew S. aureus with 8/17 (47%) MRSA. No polymicrobial infections were identified in infants. Among non-infants, 0/39 lateral infections had polymicrobial growth but 23/50 (46%) of medial infections did.
Conclusion. Local epidemiology based on anatomic location and patient age suggests a single agent (clindamycin for lateral and penicillin with beta-lactamase inhibitor for medial) may be reasonable for non-infants with uncomplicated neck infections. For infants, coverage of MRSA, regardless of anatomic location, is advisable.
Disclosures. All Authors: No reported disclosures