244. Risk Factors Associated with Complications/Sequelae in Pediatric Patients with Osteomyelitis

Background Osteoarticular infections are serious invasive pathologies in the pediatric population. They have high morbidity, especially if antimicrobial treatment is inadequate and late. Based on pediatric series patients with osteomyelitis require prolonged antibiotic schemes, long stay and high hospital costs, multiple surgical procedures and develop short and long-term sequelae. Methods A retrospective, observational, longitudinal and analytical study was conducted in patients under 17 years of age diagnosed with osteomyelitis at the National Institute of Pediatrics from January 2009 to January 2019. Demographic information, clinical presentation, microbiological, treatment and six-month follow-up were recorded. Results A total of 109 patients were included, 57 (52%) males with median age of 98 (1-205) months with predominance in previous healthy (66%). By temporality, the chronic form predominated in 72%. The history of trauma was identified in 26% and fracture 19%. The most affected bone was femur 26%. Blood culture was performed in 55%, secretion culture in 52.2% with isolation in 56%. Methicillin-susceptible Staphylococcus aureus (MSSA) was the main agent identified. Complications occurred in 37%, the most frequent was surgical wound infection in 13% followed by fracture 11%. Risk factors for complications were chronic osteomyelitis RR 5.7 (CI 1.8-17.9), Sepsis/Shock RR 3.8 (CI 1.08-13-8) and MSSA infections RR 2.7 (CI 1.01-7.5); Risk factors for surgical site infection included initial fracture RR 3.5 (CI 1-11), local ulcer RR 4.2 (CI 1.3-13.06) and MSSA infection RR 5.9 (CI 1.8-19.4). Risk factors for limitation to movement included chronic osteomyelitis RR 4.87 (CI 1.6-14), fever RR 2.5 (CI 1.15-5.5), Sepsis/shock RR 5.3 (CI 1.3-20) (p 0.013) and MSSA infection RR 4.1 (CI 1.4-11.9). Conclusion Osteomyelitis is still a health problem in our country. The diagnosis of osteomyelitis may be challenging as lack of suspicion often leads to delayed diagnosis. Knowledge of the risk factors for complications in pediatric patients could be useful to give early and proper antibiotic and surgical treatment. It is a priority to have a multidisciplinary team for the diagnosis and treatment of osteoarticular infections. Disclosures All Authors: No reported disclosures

2. Space Time Trends of Community Onset Staphylococcus aureus Infections in Children Living in Southeastern United States: 2002-2016

Background Staphylococcus aureus (S. aureus) remains a serious cause of infections in the United States and worldwide. Methicillin susceptible S. aureus (MSSA) is the cause of half of all health care–associated staphylococcal infections, and Methicillin Resistant S. aureus (MRSA) is the leading cause of community onset skin and soft tissue infections in the US. This study looks at a 15-year trend of community onset (CO)-MRSA and MSSA infections and determines ‘best’ to ‘worst’ infection trends. We identified distinct groups of CO-MRSA and MSSA infection rate trajectories by grouping census tracts of the 20 county Atlanta Metropolitan Statistical Area (MSA) between 2002 to 2016 with similar temporal trajectories. Methods This is a retrospective study from 2002-2016, using electronic health records of children living in Atlanta, Georgia with S. aureus infections and relevant US census data (at the census tract level). A group based trajectory model was applied to generate community onset S. aureus trajectory infection groups (low, high, very high) by census tract and were mapped using ArcGIS. Results Three CO-MSSA infection groups (low, high, very high) and two CO-MRSA infection groups (low, high) were detected among 909 census tracts in the 20 counties. We found ~74% of all the census tracts with S.aureus occurrence during this time period belonged to low infection rate groups for both MRSA and MSSA, with a higher proportion occurring in the less densely populated counties. Census tracts in DeKalb County, one of Atlanta’s most densely populated areas, had the highest proportion of the worst infection trend patterns (CO-MRSA high or very high, CO-MSSA high or very high). Trends of Community-Onset MRSA and MSSA Infection Rates Based on Group-based Trajectory Models Spatial patterns for CO-MRSA and CO-MSSA Trajectory Trends in the Atlanta Metropolitan Area Between 2002 to 2016 Conclusion Trends of S. aureus infection patterns, stratified by antibiotic resistance over geographic areas and time, identify communities with higher risks for MRSA infection compared to MSSA infection. Further investigation of the determinants of the trajectory groupings and the geographic outliers identified by this study may be a way to target prevention strategies aimed to prevent S. aureus infections. Disclosures All Authors: No reported disclosures

Impact of agr Functionality on the Outcome of Patients with Methicillin-Susceptible Staphylococcus aureus Bacteremia

Few studies have examined the association between methicillin-susceptible Staphylococcus aureus (MSSA) infection and accessory gene regulator ( agr ) functionality. We evaluated the association between agr dysfunction and mortality in patients with MSSA bacteremia.

Are Lactational Breast Abscesses caused by Methicillin-resistant Staphylococcus aureus Special?

Background: This study aimed to identify the differences in clinical characteristics, puncture efficacy, antibiotic use, treatment duration, breastfeeding postillness, and recurrence of patients with breast abscesses caused by methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA) infection during lactation.Methods: The clinical data of patients with breast abscesses during lactation who were treated in our hospital from January 2014 to February 2017 were reviewed. According to bacterial culture results, they were divided into MRSA (n = 260) and MSSA (n = 962) groups. Hospitalization (whether or not the patients were hospitalized), postpartum time, age, location of abscess cavities, number of abscess cavities, amount of pus, frequency of needle aspiration, failure of needle aspiration, antibiotic use, treatment duration, delactation and recurrence were compared between the two groups using a t-test and a chi-squared test.Results: We noted that only delactation was statistically significantly different between the two groups (P = 0.018). Hospitalization, postpartum time, age, location of abscess cavities, number of abscess cavities, amount of pus, frequency of needle aspiration, failure of needle aspiration, antibiotic use, treatment duration and recurrence showed no statistically significant differences (P = 0.488, P = 0.328, P = 0.494, P = 0.218, P = 0.088, P = 0.102, P = 0.712, P = 0.336, P = 0.512, P = 0.386 and P = 0.359, respectively). Conclusion: Patients with breast abscesses caused by MRSA infection during lactation presented no significant differences in the clinical manifestations, needle aspiration efficacy, antibiotic use or treatment duration compare with those caused by MSSA infection. However, patients with MRSA infected were more susceptible to delectation.

Space Time Trends of Community Onset Staphylococcus Aureus Infections in Children Living in Southeastern United States: 2002-2010

Background Staphylococcus aureus (S. aureus) remains a serious cause of infections in the U.S. and worldwide. Non antibiotic resistant Staphylococcus aureus (methicillin susceptible or MSSA) is the cause of half of all health care–associated staphylococcal infections, and methicillin resistant Staphylococcus aureus (MRSA) still is the leading cause of community onset skin and soft tissue infections in the U.S. This is the first study to spatially look at trends of both community onset MRSA and MSSA infections over nine years and determine ‘best’ to ‘worst’ infection trends over a nine year period (2002-2010),which spanned when community onset MRSA infections were occurring in epidemic proportions across the U.S. MethodsRetrospective study from 2002-2010, using electronic health records of children living in the southeastern U.S. (Atlanta, Georgia) with S. aureus infections and relevant U.S. census data (at the census tract level). The Proc Traj for SAS was applied to generate community onset MRSA and MSSA trajectory infection groups (low, high, very high, or deviant trends), and then, mapping of these trajectory groups using census tract boundaries.ResultsFrom community onset MRSA infection trend patterns (low, high, very high), only 0.8% of the census tracts showed a dramatic increase from 2002-2007 and then a gradual decline from 2008 to 2010. From community onset MSSA infection trend patterns (low and high), 85.7% of ‘high infection’ group persisted throughout the nine year period, compared to 14.3% of ‘low infection’ group over this same period. Low community onset MRSA and MSSA trend patterns were seen throughout the 20 counties of Atlanta, Georgia’s metropolitan statistical area, but more often seen in those counties less densley populated. Census tracts reflecting Atlanta’s ‘innercity’ had the highest proportion of the worst infection trend pattern (community onset MRSA-Very High-CO-MSSA-High or community onset MRSA-High-CO-MSSA-High). The deviant trend of community onset MRSA Very High- CO-MSSA Low infection were in census tracts east of downtown Atlanta. Conclusions ‘Trends’ of S. aureus infection patterns, stratified by antibiotic resistance, over geographic areas and time identify communities with higher risks for community onset MRSA infection compared to community onset MSSA infection.

Outcomes of Outpatient Parenteral Antimicrobial Therapy With Ceftriaxone for Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections—A Single-Center Observational Study

Background Staphylococcus aureus bloodstream infections (BSIs) are associated with significant morbidity and mortality. Ceftriaxone is convenient for outpatient parenteral antimicrobial therapy (OPAT), but data for this indication are limited. Methods Adult patients with methicillin-susceptible Staphylococcus aureus (MSSA) BSI discharged on OPAT with cefazolin, oxacillin, or ceftriaxone for at least 7 days were included. We compared outcomes of ceftriaxone vs either oxacillin or cefazolin. Ninety-day all-cause mortality, readmission due to MSSA infection, and microbiological failure were examined as a composite outcome and compared among groups. Rates of antibiotic switches due to intolerance were assessed. Results Of 243 patients included, 148 (61%) were discharged on ceftriaxone and 95 (39%) were discharged on either oxacillin or cefazolin. The ceftriaxone group had lower rates of intensive care unit care, endocarditis, and shorter duration of bacteremia, but higher rates of cancer diagnoses. There was no significant difference in the composite adverse outcome in the oxacillin or cefazolin group vs the ceftriaxone group (18 [19%] vs 31 [21%]; P = .70), comprising microbiological failure (6 [6.3%] vs 9 [6.1%]; P = .94), 90-day all-cause mortality (7 [7.4%] vs 15 [10.1%]; P = .46), and readmission due to MSSA infection (10 [10.5%] vs 13 [8.8%]; P = .65). Antibiotic intolerance necessitating a change was similar between the 2 groups (4 [4.2%] vs 6 [4.1%]; P = .95). Conclusions For patients with MSSA BSI discharged on OPAT, within the limitations of the small numbers and retrospective design we did not find a significant difference in outcomes for ceftriaxone therapy when compared with oxacillin or cefazolin therapy.

Positive nasal Staphylococcus aureus polymerase chain reaction assay is not sensitive in predicting concurrent or subsequent Staphylococcus aureus infection in critically ill patients

Staphylococcal infection is associated with significant morbidity and mortality in critically ill patients. Using data from 16,681 patients who had a nasal Staphylococcus aureus polymerase chain reaction (PCR) assay on admission to the intensive care unit (ICU) of Royal Perth Hospital between March 2006 and September 2016, this retrospective cohort study assessed whether nasal S. aureus colonisation on admission to an ICU was predictive of concurrent or subsequent S. aureus infections. Culture-proven S. aureus infections were identified using the hospital microbiology database. Of the 16,681 patients included, 565 (3.4%) had a positive methicillin-resistant S. aureus (MRSA) assay, 146 (0.9%) had a positive methicillin-sensitive S. aureus (MSSA) assay and eight (0.05%) had both positive MRSA and MSSA assays. Of those 565 patients with a positive MRSA PCR assay, 79 (13.8%) had concurrent or subsequent MRSA infections. Of those 146 patients with a positive MSSA PCR assay, only 5 (3.4%) had MSSA infection. The sensitivity and specificity for the MRSA PCR assay in predicting concurrent or subsequent MRSA infection were 72.7% (95% confidence intervals (CI) 63.4%–80.8%) and 97.0% (95% CI 96.8%–97.3%), respectively. The sensitivity and specificity for the MSSA PCR assay in predicting concurrent or subsequent MSSA infection were 3.3% (95% CI 1.1%–7.6%) and 99.1% (95% CI 98.9%–99.2%), respectively. Both nasal MRSA and MSSA PCR assays had a high specificity and negative predictive value in predicting MRSA and MSSA infections, respectively, suggesting that in centres without endemic S. aureus infections, a negative nasal MRSA or MSSA PCR assay may be useful to reduce unnecessary empirical antibiotic therapy against S. aureus.

Reduced Mortality of Staphylococcus aureus Bacteremia in a Retrospective Cohort Study of 2139 Patients: 2007–2015

Background Understanding the changing epidemiology of Staphylococcus aureus bacteremia, as well as the variables associated with poor outcomes, can yield insight into potential interventions. Methods This study was a retrospective, observational cohort study of adult patients at an academic medical center in New York City who had S. aureus bloodstream infections between 1 January 2007 and 31 December 2015. Participants were divided into 3 periods: group 1 (2007–2009), group 2 (2010–2012), and group 3 (2013–2015) for trend analysis. All clinical strains were genotyped (spa.). The main outcome was 30-day all-cause mortality. Results There were 1264 episodes of methicillin-susceptible S. aureus (MSSA) and 875 episodes of methicillin-resistant S. aureus (MRSA) bacteremia, with a rising proportion due to MSSA (55% group 1; 59% group 2; 63% group 3; P = .03.) There were no significant changes in average age, gender, Charlson score, and distribution of strain genotypes. Mortality in MRSA infection was unchanged (25% group 1; 25% group 2; 26% group 3), while mortality in MSSA infection significantly declined (18% group 1; 18% group 2; 13% group 3). The average time to antistaphylococcal therapy (AST) in MSSA infection declined during the study (3.7 days group 1; 3.5 group 2; 2.2 group 3). In multivariate analysis, AST within 7 days of initial positive MSSA culture was associated with survival. Conclusions Mortality in MSSA bloodstream infection is declining, associated with a decrease in time to targeted therapy. These results emphasize the potential for rapid diagnostics and early optimization of treatment to impact outcomes in MSSA bacteremia.

Staphylococcal Infection in California: Strain Dominancy and Trends, a Good Day Against Superbug

In California, an average of 41,900 patients are diagnosed annually with Staphylococcus bacterial infection; out of these, 24,090 patients have methicillin-resistant Staphylococcus aureus (MRSA) infection and 17,810 patients have methicillin-sensitive Staphylococcus aureus (MSSA) infection. The aim of this paper is to find out whether there is a significant difference in strain dominancy and in what direction. The paper gathered and analyzed data for period of five years of infection rate due to Staphylococcus aureus. This study indicates that a significant difference in dominancy exists, the MRSA infection rate (an average of five years period) is 1.35 times higher than the MSSA infection rate (P-value < 0.05, CI: 95%), but the gap between the two infection rates is decreasing. The infection rate of both MRSA and MSSA is in a path of decline.