Dual-site blood culture yield and time to positivity in neonatal late-onset sepsis

ObjectiveTo determine whether culture yield and time to positivity (TTP) differ between peripheral and central vascular catheter-derived blood cultures (BCx) in neonatal intensive care unit (NICU) patients evaluated for late-onset sepsis.DesignSingle-centre, retrospective, observational study.SettingLevel IV NICU.ParticipantsThe study included infants >72 hours old admitted to NICU in 2007–2019 with culture-confirmed bacteraemia. All episodes had simultaneous BCx drawn from a peripheral site and a vascular catheter (‘catheter culture’).Main outcome measuresDual-site culture yield and TTP.ResultsAmong 179 episodes of late-onset bacteraemia (among 167 infants) with concurrently drawn peripheral and catheter BCx, the majority (67%, 120 of 179) were positive from both sites, compared with 17% (30 of 179) with positive catheter cultures only and 16% (29 of 179) with positive peripheral cultures only. 66% (19 of 29) of episodes with only positive peripheral BCx grew coagulase-negative Staphylococcus, while 34% (10 of 29) were recognised bacterial pathogens. Among 120 episodes with both peripheral and catheter BCx growth, catheter cultures demonstrated bacterial growth prior to paired peripheral cultures in 78% of episodes (93 of 120, p<0.001). The median TTP was significantly shorter in catheter compared with peripheral cultures (15.0 hours vs 16.8 hours, p<0.001). The median elapsed time between paired catheter and peripheral culture growth was 1.3 hours.ConclusionConcurrently drawn peripheral and catheter BCx had similar yield. While a majority of episodes demonstrated dual-site BCx growth, a small but important minority of episodes grew virulent pathogens from either culture site alone. While dual-site culture practices may be useful, clinicians should balance the gain in sensitivity of bacteraemia detection against additive contamination risk.

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

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)

A Prospective Study to Assess the Optimal Incubation Times for Culture and Aerobic Bacterial Profile in Prosthetic Joint Infections

Introduction With an increase in the number of total joint arthroplasties, the count of prosthetic joint infections (PJIs) is also increasing and has become a nightmare for an orthopaedic surgeon. Microbiological diagnosis is important for administering definitive antimicrobial treatment. Negative culture reports hamper patient management and prolonged incubation periods have increased the culture yield but at the risk of culture contamination in conventional microbiology settings. Thus, we aimed to optimize the best incubation time for culture and the aerobic bacterial profile of PJIs. Material and Methods Over a year, samples from clinically suspected PJI patients were collected and processed for culture using standard techniques. The samples were incubated for up to 10 days with daily subculturing on to solid media. The bacterial isolates were identified and antibiotic susceptibility was performed. Results Out of 200 patients, 105 were included in the study and samples were collected in triplicate. In 70 cases culture was positive and 35 were culture negative PJIs. Mean incubation days to culture positivity was 3.6 days with 97.14% culture positivity seen by the seventh day of incubation. Twenty-four percent methicillin-resistant Staphylococcus aureus, and more than 50% extended spectrum β lactamase producing Klebsiella pneumoniae and Escherichia coli were isolated. Discussion Culture positivity in PJIs provides definitive evidence of infection and guides the treatment. Increasing the incubation times can help in maximizing the culture yield, and we found that 97.14% pathogens grew within 7 days of incubation. Prolonging it further would not provide an added advantage especially in a resource-constraint setting.

ELIZABETHKINGIA MENINGOSEPTICA BACTEREMIA IN A NEONATE: A RARE CASE REPORT FROM A TERTIARY CARE CENTRE OF TRIPURA

Blood from a two day old male baby with history of respiratory distress and meconium aspiration was sent to the Department of Microbiology for culture. Blood culture yield non haemolytic small colonies of 1-2 mm on Blood agar and no growth on MacConkey agar.Based upon the colony characteristics, biochemical reactions, antimicrobial susceptibility pattern and identification by conventional and Vitek 2 Compact system, the isolate was identified as Elizabethkingia meningoseptica which is a rare cause of bacteremia in neonates.

Effective use of Penicillin to Improve Culture Yield for Mycobacterium tuberculosis

Objective: To compare LJ media and LJ media with penicillin for the growth of Mycobacterium tuberculosis and contamination, in pulmonary tuberculosis (PTB) suspected patients. Methods: A total of 300 PTB suspected cases at National Tuberculosis center (NTC) for analyzed for culture and contamination. Early morning sputum samples were collected in sterile leak-proof falcon tube. Digestion, decontamination and homogenization of sputum were done using NALC-NaOH (Modified Petroff method). The sputum sample was processed on LJ media and penicillin added LJ media and incubated at 37. Cultures were examined after 8 weeks. Results: All the PTB suspected cases were compared in LJ media and LJ media with penicillin, 29.7% (89) were positive, 21% (63) were contaminated on LJ media whereas 41% (123) were positive, 3.7 % (11) were contaminated on penicillin added LJ media. Also, 25 (8%) were 1+ grading, 14 (4.7%) were 2+ grading, whereas 81 (27%) and 45 (15%) were 3+ grading LJ + Penicillin and LJ media respectively. Conclusion: Contamination was reduced by 17.3% with the addition of penicillin to LJ media. And isolation of total positive cultures was enhanced by 11.3%.