Use of fourth-generation rapid combined antigen and antibody diagnostic tests for the detection of acute HIV infection in a community centre for men who have sex with men, between 2016 and 2019

Objective To assess the use of fourth-generation rapid diagnostic tests in identifying acute infection of Human Immunodeficiency Virus (HIV). Methods BCN Checkpoint promotes sexual health among men who have sex with men (MSM), with a focus on diagnosing HIV early, initiating combined antiretroviral treatment (cART) promptly, and recommending regular repeat testing for those who have tested negative. This cross-sectional study included all test results obtained at the centre between 25 March 2016 and 24 March 2019. The Alere™ HIV Combo (now rebranded to Determine™ HIV Ultra, from Abbott) was used to detect p24 antigen (p24 Ag) and/or immunoglobulin M (IgM) and G (IgG) antibodies to HIV-1/HIV-2 (HIV Ab). Rapid polymerase chain reaction (PCR) confirmatory testing and Western blot (WB) were performed for clients with a positive rapid test result. Confirmed HIV cases were promptly referred to the HIV unit for care and cART prescription. Results A total of 12,961 clients attended BCN Checkpoint during the study and 27,298 rapid tests were performed. 450 tests were found to be reactive, of which 430 confirmed as HIV-positive, representing a prevalence of 3.32%. Four confirmed cases (0.93%) were detected as “p24 Ag only”, nine (2.09%) as “both p24 and HIV Ab” and 417 (96.98%) as “HIV Ab only”. The “p24 Ag only” group had a 1-log higher viral load than the other groups and initiated treatment on the following working day. Overall, there were 20 false-positive results (0.07% and 4.44% of total and reactive tests, respectively), of which 10 positive for “p24 Ag only” and 10 for “HIV Ab only”. Conclusions Four Acute HIV Infections (AHI), with very high viral loads, have been detected with the “p24 Ag only” while the HIV Ab were still absent. Referral to the HIV unit and initiation of cART on the following working day contributed to improving persons’ health and to reduce HIV transmission chain.

Rapid polymerase chain reaction test for the early diagnosis of gonococcal keratoconjunctivitis

Purposes: A case of gonococcal keratoconjunctivitis rapidly diagnosed by a vaginal swab PCR Xpert® CT/NG assay. Methods: Case report. Results: A 26-year-old woman presented to our emergency department with severe perilimbal stromal melting in both eyes and profuse purulent discharge for one day. Upon emergent ocular consultation, gonococcal keratoconjunctivitis was suspected. A vaginal swab was sent for rapid PCR Xpert® CT/NG assay which reported positive Neisseria gonorrhoeae (NG) and Chlamydia Trachoma (CT) DNA detection within 90 min. Due to the rapid diagnosis, adequate medical intervention with ceftriaxone injection was administered. Gonococcal keratitis with stromal melting was stabilized within 5 days of presentation. The patient was discharged with complete epithelial healing by the 8th day. However, 10 weeks after discharge, inadvertent rubbing of the left eye resulted in corneal perforation with iris prolapse. Lamellar keratoplasty with corneal patch graft was performed with amniotic membrane grafting. Xpert® CT/NG assay was performed again with conjunctival swab for recurring mild eye discharge. Both NG and CT were negative. The patient thus stabilized with no further complications. Conclusions: Rapid stromal melting can occur with un-diagnosed or delayed diagnosis of gonorrhea with ocular involvement. Speedy and accurate diagnosis by the highly sensitive and specific Xpert® CT/NG assay can provide early definite diagnosis for prompt treatment in prevention of gonococcal infection induced corneal perforations.

2790. Respiratory Viral Testing and Antimicrobial De-escalation Among Hospitalized Patients at a Tertiary Care Facility, 2015–2016: A Matched Cohort Study Series

Background The use of multiplex respiratory viral panels (RVP) is increasing. They have the potential to reduce unnecessary antibiotic use, but data are limited on their clinical effectiveness. Our objective was to estimate risk differences for antimicrobial de-escalation (discontinuation, intravenous to oral, or spectrum narrowing) between different sequences and results of RVP and rapid polymerase chain reaction (PCR) tests for influenza +/− respiratory syncytial virus. Methods We conducted a retrospective chart review of adults (age ≥18 years) admitted to a floor or stepdown unit at University of North Carolina Hospitals who had a respiratory viral test (RVT) within 48 hours of admission between September 2015 and April 2016. We estimated 3-day RDs for the relation between RVT and antimicrobial de-escalation. To control confounding and account for the 37-hour mean lag between PCR (faster) and RVP (slower) tests resulting, we leveraged the treatment decision design over a series of 1:1 matched cohort studies. Each targeted a clinically relevant scenario: (1) ordering RVP test (vs no RVP order) after learning PCR status; (2) learning RVP+ result (vs. no RVP result) after knowing PCR status; (3) learning RVP+ result (vs. RVP–) after knowing PCR–status; and (4) learning RVP+ result (vs. RVP–) given no prior PCR. For each subcohort, referent patients were matched to index patients by race, gender, RVT in prior month (y/n), age (±10 years), and season (±1.7 months). Results The overall cohort (n = 1,342) was 61% White, 29% African American, and 51% female. Median age was 56 years (IQR 39–69). Across all matched subcohorts (Figure 1), the matching success rate was 79–88% and referent frequency of antimicrobial de-escalation ranged 0.6%–1.9%. In scenario 1, ordering RVP results was associated with higher de-escalation (3-day RD 7.6%; 95% confidence intervals [CI] 3.2%, 12.1%). In scenarios 2–4, learning RVP+ results was associated with more frequent de-escalation (3-day RDs 14.8%, 13.8%, and 15.4%). Conclusion RVP testing and positive RVP results were associated with increased antimicrobial de-escalation, although de-escalation was overall infrequent. Future research should assess effect modification across subgroups and evaluate cost-effectiveness. Disclosures All authors: No reported disclosures.

1400. Impact of a Multiplex Polymerase Chain Reaction Meningitis/Encephalitis Panel and Antimicrobial Stewardship Bundle on Antimicrobial Use in Patients with Suspected Meningitis or Encephalitis

Background Optimal treatment of meningitis relies on prompt diagnostic evaluation and initiation of appropriate antimicrobials. The meningitis/encephalitis panel (MEP) is a multiplex rapid polymerase chain reaction, with the ability to detect 14 community-acquired pathogens in 1 hour. The purpose of this study was to evaluate impact of the MEP on de-escalation of antimicrobials in adult inpatients with suspected meningitis at a large community teaching hospital. Methods This single-center retrospective quasi-experimental pre/post study included adults admitted for ≥48 hours and initiated on antimicrobial therapy for suspected meningitis. Those with healthcare-associated meningitis, immunosuppression, initiation of antimicrobials >8 hours prior to lumbar puncture (LP), and use of antimicrobials for another indication were excluded. The pre-group included patients admitted prior to MEP introduction. The post-group included patients with the MEP performed. An antimicrobial stewardship bundle consisting of a meningitis order set, provider education, and use of a real-time meningitis alert in clinical decision support software was also implemented in the post-group. The primary outcome was percentage of patients experiencing antimicrobial de-escalation ≤48 hours after LP. Secondary outcomes included time to de-escalation, total duration of antimicrobial therapy (DOT), and hospital length of stay (LOS). Results A total of 45 patients were included in the study (23 pre-group and 22 post-group). Baseline characteristics were similar between groups. The percentage of patients experiencing de-escalation of antimicrobials ≤ 48 hours after LP increased by 44% in the post-group (82% vs. 38%, P = 0.005). The overall median time to de-escalation of antimicrobials decreased by 35 hours [11.1 (IQR 5.6, 17.6) vs. 46.1 (IQR 18.4, 66.5); P = 0.002] and the median time to de-escalation after LP decreased by 38 hours [13.6 (IQR 8.3, 20.3) vs. 51.6 (IQR 44.2, 69.8); P < 0.001]. No statistically significant difference in hospital LOS or total DOT was seen. Conclusion Implementation of the MEP and antimicrobial stewardship bundle increased the percentage of patients de-escalated in 48 hours and decreased the time to de-escalation. However, this did not impact the total DOT or hospital LOS. Disclosures All authors: No reported disclosures.

A revisit to a low-cost method for the isolation of microsatellite markers: the case of the endangered Malayan tapir (Tapirus indicus)

There are many approaches to develop microsatellite markers. We revisited an easy and rapid Polymerase Chain Reaction (PCR)-cloning-sequencing method to design microsatellite markers for Tapirus indicus. Using six random amplified microsatellite (RAM) markers, this study had rapidly generated 45 unique genomic sequences containing microsatellites. After screening 15 terminal and seven intermediate microsatellite loci, we shortlisted five and seven which were amplified either by single- or multiplex PCR using the economical three-primer PCR method. Genotyping attempts were made with ten Tapirus indicus individuals using three of the terminal microsatellite loci and all seven intermediate loci. However, none of the terminal microsatellite loci were considered useful for population genotyping studies, while the seven intermediate loci showed good amplification but were monomorphic in the ten samples. Despite successful detection of amplified loci, we would like to highlight that, researchers who are interested in this alternative method for isolation of microsatellite loci to be cautious and be aware of the limitations and downfalls reported herein that could render these loci unsuitable for population genotyping.

Delays in the diagnosis and treatment of bone and joint tuberculosis in the United Kingdom

Aims Tuberculosis (TB) infection of bones and joints accounts for 6.7% of TB cases in England, and is associated with significant morbidity and disability. Public Health England reports that patients with TB experience delays in diagnosis and treatment. Our aims were to determine the demographics, presentation and investigation of patients with a TB infection of bones and joints, to help doctors assessing potential cases and to identify avoidable delays. Patients and Methods This was a retrospective observational study of all adults with positive TB cultures on specimens taken at a tertiary orthopaedic centre between June 2012 and May 2014. A laboratory information system search identified the patients. The demographics, clinical presentation, radiology, histopathology and key clinical dates were obtained from medical records. Results A total of 31 adult patients were identified. Their median age was 37 years (interquartile range (IQR): 29 to 53); 21 (68%) were male; 89% were migrants. The main sites affected were joints (10, 32%), the spine (8, 26%) and long bones (6, 19%); 8 (26%) had multifocal disease. The most common presenting symptoms were pain (29/31, 94%) and swelling (26/28, 93%). ‘Typical’ symptoms of TB, such as fever, sweats and weight loss, were uncommon. Patients waited a median of seven months (IQR 3 to 13.5) between the onset of symptoms and referral to the tertiary centre and 2.3 months (IQR 1.6 to 3.4.)) between referral and starting treatment. Radiology suggested TB in 26 (84%), but in seven patients (23%) the initial biopsy specimens were not sent for mycobacterial culture, necessitating a second biopsy. Rapid Polymerase Chain Reaction-based testing for TB using Xpert MTB/RIF was performed in five patients; 4 (80%) tested positive for TB. These patients had a reduced time between the diagnostic biopsy and starting treatment than those whose samples were not tested (median eight days versus 36 days, p = 0.016). Conclusion Patients with bone and joint TB experience delays in diagnosis and treatment, some of which are avoidable. Maintaining a high index of clinical suspicion and sending specimens for mycobacterial culture are crucial to avoid missing cases. Rapid diagnostic tests reduce delays and should be performed on patients with radiological features of TB. Cite this article: Bone Joint J 2018;100-B:119–24.

Identification of Smallanthus sonchifolius in herbal tea mixtures by PCR and DART/TOF-MS methods

The identification of yacon, a medicinal plant, in tea mixtures by rapid Polymerase Chain Reaction (PCR) and the Direct Analysis in Real Time coupled with Time-of-Flight Mass Spectrometry (DART/TOF-MS) method were evaluated. Three tea products and a pure yacon tea were analysed using the molecular method PCR, concretely the intraspecific variation of the internal transcribed spacer (ITS) regions of rDNA and the DART method coupled with TOF-MS. The results show the reliability of PCR and restriction cleavage of the ITS as a combined approach to confirm the presence of yacon in herbal tea mixtures. Three fragments of approximately 700, 408, and 235 bp in length are present when yacon is a part of the herbal tea mixture. The Principal Component Analysis (PCA) based on the fingerprints of the complete Total Ion Current (TIC) mass spectra shows sufficient separation of herbal teas with and without yacon leaves. The reported methods are technically rapid and can be used as an effective tool for the purposes of yacon identification or authentication.