1307. The Mycoplasma Conundrum

Background Lockdown for Covid 19 between March 15 - 30, 2020 lead to sudden closures of schools, public gatherings, all but essential businesses, and stay-at-home orders. Between then and the end of April 2020, literally all enveloped respiratory viruses declined to virtually undetectable levels, suggesting a successful interruption of transmission. Weekly percentage positivity rates for M. pneumoniae and all other respiratory viruses from BioFire Syndromic Trends for weeks ending 3/7/2020- 4/24/2020. Weekly percentage positive rates are shown, with the Rhinovirus/Enterovirus rate divided by 3 and the M. pneumoniae rate multiplied by 10 to fit on the same scale. Methods We used the percentage positivity rates from BioFire Syndromic Trends and from GenMark Diagnostics to examine the post lockdown response of M. pneumoniae versus other respiratory viruses on the Respiratory Virus Panel (RP 2.0) Results As has been reported (Nawrocki J., et al, OFID 2021) and as shown in Figure 1, there was a rapid drop in the positivity rate for all enveloped respiratory viruses by 85.6% from an average rate of 2.014% positive for the week ending 3/14/20 to 0.29% for the week ending 4/18/20, while the positivity rate for M. pneumoniae actually increased by 44% from 0.536 % to 0.772%. The increase in M. pneumoniae positivity rate from its baseline of 0.51 ± 0.38 between 1/25/20 - 3/21/20 vs 0.71 ± 0.09 between 3/28/20 - 4/25/20 was significantly higher by t test, p=0.00574. Data from GenMark was available only monthly but also showed an upward rise from march to April, 2020. Conclusion It is well documented that M. pneumoniae is transmitted through respiratory mechanisms, yet lockdown measures sufficient to dramatically reduce ordinary respiratory virus transmission had no comparable effect on transmission of Mycoplasma pneumoniae. It is also well known that M. pneumoniae persists in the respiratory tract as long as months after an infection. Therefore, it is possible that this reservoir continued to be a source of transmission for M. pneumoniae, even though lockdown measures effectively interrupted the enveloped respiratory viruses. Disclosures Kenneth Rand, M.D., BioFire Diagnostics (Advisor or Review Panel member, Research Grant or Support)

O12: IHC ANALYSIS OF RESIDUAL DISEASE POST NEOADJUVANT TRASTUZUMAB FOR EARLY STAGE BREAST CANCER REVEALS ER/HER2 CROSSTALK THROUGH INCREASED ER SIGNALLING

Introduction Therapeutic pressure functionally affects oncogenes and related signalling pathways through dynamic alterations in transcriptional and epigenetic alterations. Altered receptor status occurs throughout tumour progression and may be influenced by adjuvant and neoadjuvant therapies. Recurrent transcriptional remodelling events have been described in the progression of primary breast cancer to metastasis, including increased tyrosine kinase signalling, specifically Her2, and loss of ESR1 gene expression. We hypothesise that in the setting of tyrosine kinase inhibition, an increase in estrogen receptor (ER) signalling is observed. Method A database of patients recruited to ICORG trial 07/09 was queried to identify patients with histologically confirmed, Her2-overexpressing or Her2 amplified, nonmetastatic, invasive breast cancer who received neoadjuvant trastuzumab, alone or in combination with neoadjuvant systemic chemotherapy. Clinicopathological characteristics recorded include age at diagnosis, clinical stage, receptor status and percentage positivity, and pathological complete response. Result A total of 55 patients identified on ICORG trial 09/07 received neoadjuvant trastuzumab. Of these, 27 achieved a complete pathological response (49%; n=27/55). In those with residual disease, a gain in mean ER staining percentage positivity was observed in the residual disease compared to diagnostic biopsy staining (59.22 vs 45.11; p=0.03). A corresponding loss in Her2 percentage staining positivity was also observed (p=0.006). Conclusion An inverse correlation was observed between loss of Her2 positivity and percentage gain in ER staining in patients with residual disease following treatment with neoadjuvant trastuzumab. Further study is needed to elucidate the regulatory mechanism of ER/Her2 crosstalk, which may be epigenetically regulated through DNA methylation. Take-home message ER/Her2 crosstalk can be demonstrated clinically in IHC analysis of patients with residual disease post neoadjuvant trastuzumab. Tyrosine kinase inhibition in the form of neoadjuvant trastuzumab results in loss of Her2 signalling and corresponding gain in ER signalling.

Autoantibodies among HIV-1 infected individuals and the effect of Anti-retroviral therapy (ART) on it.

Background:: Antiretroviral therapy (ART) has led to a decline in autoimmune diseases but lacks studies on its effect on autoantibodies. Methods: A cross-sectional study with archived samples from 100 paired HIV-1 infected ART naïve and experienced individuals and 100 prospectively collected matched blood-donor controls. Antinuclear antibody, IgG anticardiolipin antibody, IgM and IgG β2 glycoprotein-1 antibodies, and total IgG levels were detected. Results are expressed as mean with standard deviation (SD), median, percentage positivity, and a p<0.05 is considered significant. The study was approved by the Institutional Review Board. Results: The median viral load of the treatment naïve samples was 4.34 Log copies/mL while all were virally suppressed post ART with a median duration of treatment for 12 months (range: 3-36 months). The percentage positivity of antinuclear antibody was 5% among ART naïve and controls with a decrease to 2% post ART (p= 0.441). The positivity for anti-cardiolipin antibody was 15% among ART naïve while none of the ART experienced or controls were positive (p<0.05). IgM β2 glycoprotein-1 was 4%, 1% and 3% among ART naïve, treated and controls respectively (p<0.05). IgG β2 glycoprotein-1 was 2% among ART naïve while none of the treated and controls were positive (p<0.05). The mean total IgG level among ART naïve, experienced, and controls were 21.82 (SD 6.67), 16.91 (SD 3.38), 13.70 (SD 2.24) grams/Litre respectively (p<0.05). Conclusion: ART has a significant effect on IgG anti-cardiolipin antibody and total IgG but only a marginal effect on ANA, IgM, and IgG β2 glycoprotein-1 antibodies.

Evaluation of markers of thrombosis and fibrinolysis in malaria patients in tertiary care hospital in Central India

Background: Cases of malaria are known to be associated with variable degrees of coagulopathy asevident from abnormalities of screening coagulation assays in a large number of patients during theillness. However, attempts to use laboratory parameters as indicators of the severity of theunderlying coagulopathy and for monitoring disease progression have met with only partial success.Methods: This prospective study was conducted in the department of Pathology in RuxmanibenDeepchand Gardi Medical College, Ujjain. Blood samples of all the patients diagnosed positive withmalaria were collected in vials containing ethylene tetra-acetic acid tri potassium salt forhematological parameters and in trisodium citrate tubes for coagulation assays. Result: Out of thetotal positive cases, PT was prolonged in 65% of total cases, Percentage positivity for prolonged PTfor falciparum and vivax is 60% and 68.5% respectively. APTT has raised 47% of malaria positivecases with percentage positivity for falciparum and vivax 48% and 45.7% respectively. 55% of totalcases showed raised levels of fibrin degradation products, which included 48% of falciparum casesand 60% of vivax cases. Out of 120 positive cases of malaria, D- Dimer was raised 41.7% cases.Conclusion: As blood is the chief component affected by malaria, not only proper examination ofperipheral smears is required for detection and species identification, but a careful evaluation ofother laboratory parameters should be done irrespective of the malarial species for the earlydiagnosis of compensatory and non-compensatory consumptive coagulopathy.

Situation Analysis of Ticks and Seroprevalence of Theileria Parva in Two Farming Systems in Two Districts of Uganda.

Background: In Uganda, livestock supports the livelihoods of poor people, fulfilling multiple-economic, social, and risk management functions. However, its productivity is constrained by ticks and tick-borne diseases (TTBDs), more importantly, East Cost Fever (ECF) whose epidemiology is not well known and understood in the cattle corridor. Methodology: A cross-sectional study was carried out in pastoral and mixed crop-livestock farming systems in Nakaseke and Nakasongola districts to understand the; local composition of ticks, the prevalence of Theileria parva and management of ECF and ticks. A structured closed-ended questionnaire was administered in (189) pastoral and (197) mixed-crop livestock households which were randomly selected, and a total of 384 calves were sampled. The tick challenge was assessed in situ on one side of the animal body considering different predilection sites. The prevalence of ECF was assessed by collecting whole blood in Ethylene Diamine Tetra acetic Acid (EDTA) tubes following veni-puncture. Thin and thick blood smears were made and serum samples were collected for determination of seroprevalence of ECF, using Enzyme-Linked Immunosorbent Assay (ELISA). Results/Discussion: From a sample of 384 cattle surveyed, 316 (82.3%) were found to be infested with ticks of different species at their preferential predilection sites. Rhipicephalus. appendiculatus was the most abundant tick species (88.2%), followed by Ambryomma. variegatum (7.5%) and lastly Rhipicephalus. evertsi evertsi (4.3%). 80.7% of respondents believe that there was a tick infestation problem severe and ticks were managed on regular basis mainly by using acaricides (65.3%). In the pastoral farming system, no ticks were found on calves below 6 months old. The seroprevalence of T. parva was below 20% percentage positivity (pp)in calves below 4 months old, thereafter rising to 65% at 5 months, and then dropping to 20% from the age of 6 to 9 months. In mixed crop-livestock farming system, all age groups of cattle were exposed to tick challenge. The prevalence of T. parva increased from 1-month old calf reaching a peak in 2-3 months old calves but drastically dropped in calves 4 months old. Thereafter, it gradually built up to 70% in animals 7 months old. There was a moderate correlation between the mean number of R. appendiculatus ticks and seroprevalence of T. parva (r =0.47) and there was no significant difference between age category and percentage positivity of T. parva (p = 0.969). However, there was a relationship between mean number of ticks and farming system (p = 0.019) as well as percentage positivity of T. parva and farming system (p = 0.007)Conclusion: ECF was prevalent in the two farming systems albeit frequent application of acaricides on animals as reported by most of the respondents. Further longitudinal studies required to assess seasonal variations of TTBDs, prevalence of other tick-borne diseases and acaricide resistance status.