Lab Matters Summer 2021 | Page 65

APHL 2021 Poster Abstracts
Cp in discrete “ burst ” events occurring at the nuclear membrane . Cytoplasmic retention of Eps- pgRNA-derived Cp assemblages was rescued by expressing Eps + pgRNA , suggesting that pgRNA and Cp trafficking are interdependent . These results reveal that nucleocytoplasmic transitions of Cp / capsids are prevalent , typically occur in conjunction with nuclear membrane breakdown ; and are regulated by viral RNA .
Presenter : Sofia Romero , University of Wisconsin- Madison , seromero @ wisc . edu
Phenotypic Characterization of Genetically-related and Epidemiologically-linked Carbapenem-resistant Acinetobacter baumannii Isolates
D . Curry 1 , H . Butz 1 , T . Gallagher 1 , M . Vowles 2 , E . Young 1 , K . Oakeson 1 , A . Rossi ; 1 Utah Public Health Laboratory , Taylorsville , UT , 2 Utah Department of Health , Salt Lake City , UT
Carbapenem-resistant Acinetobacter baumannii ( CRAB ) is a highly prevalent nosocomial pathogen that causes significant mortality and morbidity . Understanding genetic determinants that promote CRAB ’ s ability to adapt and survive in the hospital environment are of pivotal importance for defining effective infection prevention interventions and informing patient care . In this study , we characterized 15 CRAB isolates from outbreaks occurring at three epidemiologically linked facilities over a one-year period ( Facility A , May 2018 ; Unit B , December 2018 ; Unit C , May 2019 ). We screened these highly related isolates for phenotypic variations that could be potentially linked to specific genetic changes . The isolates were recovered from clinical and colonization cultures , as well as environmental sources . WGS was performed on an Illumina MiSeq platform . Strain relatedness was investigated through phylogenetic analysis of 2,637 proteincoding genes present in every isolate . Antimicrobial susceptibility testing ( AST ) was performed according to the CLSI M100 guidelines . MIC values were determined by broth microdilution using Sensititre GNX2F panels ( ThermoFisher Scientific ). Biofilm formation was also assessed through the quantification of crystal violet absorption . Susceptibilities to disinfectants ( ethanol , chlorhexidine , benzalkonium chloride , hydrogen peroxide and hypochlorite ) were assessed via spotting on solid medium or disk diffusion assays . All the CRAB isolates characterized here belong to the Pasteur MLST type 2 and harbor an OXA-235 carbapenemase gene . Isolates from Facility A and Unit B displayed on average 3.6 SNPs when reciprocally compared . Unit C isolates displayed a greater number of average SNPs when compared to either Facility A ( 986.4 ) or Unit B ( 989.5 ). All isolates were multi-drug resistant and displayed susceptibility to polymyxin antibiotics . Resistance to aminoglycosides was variable and all isolates were susceptible to amikacin . All isolates were able to form strong biofilms , and did not display any difference in susceptibility to ethanol , hydrogen peroxide , and hypochlorite . However , the isolates from Unit C were significantly more susceptible to chlorhexidine and benzalkonium chloride . Interestingly , non-synonymous SNPs and a nonsense mutation in two efflux pump genes were detected in the Unit C isolates . The genotype-phenotype relationships linked to these SNPs and their relevance are currently under investigation . This work illustrates how the phenotypic and genomic characterization of likely clonal isolates at temporally defined intervals can inform CRAB biology and its evolution in the nosocomial environment .
Presenter : Dylan Curry , Utah Public Health Laboratory , dcurry @ utah . gov
Validation of Patient-collected Swab Specimens for the Diagnosis of Sexually Transmitted Infections in a Clinical Setting
S . Mardanu-Budiono , R . Gomez , J . Weiner , E . Osuala , V . Bearden , H . Hermus , M . Khubbar and S . Bhattacharyya , City of Milwaukee Health Department , Milwaukee , WI
Objective : To compare the accuracy of patient-collected specimens ( PCS ) vs . clinician-collected specimens ( CCS ) for screening and diagnosis of STIs . Milwaukee Health Department ( MHD ) STD clinicians recognized a need for patient-collected sampling for clients not needing a complete STI screening exam and to streamline client intake . To determine whether PCS are as accurate as CCS in terms of diagnosing STIs , MHDL validated the use of PCS sampling by comparing patient-collected genital and extra-genital swabs to standard CCS sampling techniques . In this study PCS was validated for nucleic acid amplification test ( NAAT ) screening of Chlamydia trachomatis ( CT ), Neisseria gonorrhoeae ( GC ), Trichomonas vaginalis ( TV ), and Mycoplasma genitalium ( MG ) and conventional GC culture including isolation and identification .
Methods : CCS was used as the gold reference standard which assumes 100 % accuracy . For GC culture and antibiotic susceptibility testing , MHD STD Clinic patients obtained PCS from vaginal ( CCS : Cervical ), penile meatal ( CCS : Urethral ), pharyngeal , or rectal sites , and providers obtained CCS from the same patient and site . Ten swab samples sets ( PCS and CCS ) were collected from each site . Forty blinded pretested patient-collected clinical swab samples were received from partner clinic for NAAT performance verification of patient-collected verses clinician-collected vaginal swab for screening of CT , GC , TV and / or MG using Panther system ( Hologic ® Inc .). Clients received collection kit manufacturer instructions on how to self-collect vaginal , penile meatal , rectal , and pharyngeal specimens .
Results : True positive ( TP ), false positive ( FP ), true negative ( TN ), and false negative ( FN ) results from each study were extracted to construct two-by-two tables and calculate test sensitivity and specificity . All vaginal samples for NAAT assays except one negative for TV which turned out to be invalid at MHDL ( insufficient sample for repeat ) showed comparable results between the performing laboratories . Concordance with the expected result was 97.6 % overall . There was 100 % agreement between results of GC culture for CCS and PCS , indicating patient-collected screening would be a valid alternative .
Conclusion : Overall more than 95 % agreement obtained for STI NAATs and GC culture seen . This study indicates self-collection as sensitive and accurate as clinician collection to accurately diagnose STDs and improve operational efficiency , allowing MHD staff to detect and prevent more cases of STDs . Future innovative interventions such as internet-based or mail-in home and community service testing for patients that are hard to reach , refuse to go for clinician-based testing , or who decline an examination would eliminate barriers to STI testing .
Presenter : Joshua Weiner , City of Milwaukee Health Department , jweiner @ milwaukee . gov
Infectious Disease
Summer 2021 LAB MATTERS 63