Andrew Henderson

Infectious diseases physician and clinical microbiologist. Views are my own.

[Andrew Henderson @Hendonet]

Great team effort to get this done! @evanbursle @padstamundo @jesusrbano @davidantibiotic @adm_stewart

[Antibiotic Steward Bassam Ghanem 🅱️C🆔🅿️🌟 @ABsteward]

🆕🔥 @CMIJournal @Hendonet @padstamundo @davidantibiotic @jesusrbano @adm_stewart
A systematic review of antimicrobial susceptibility testing as a tool in clinical trials assessing antimicrobials against infections due to Gram negative pathogens #IDTwitter https://t.co/ymcynHGJiw

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @draghafur @davidantibiotic @MerinoTrial Yep

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @draghafur @davidantibiotic @MerinoTrial Interesting thought! Here is the PTZ zone diameter distribution stratified by MIC for isolates with VITEK MIC <16mg/L. I can do the same plot stratified by BL gene present, but almost all the 16mg/L and 32mg/L have OXA1 present.

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @draghafur @davidantibiotic @MerinoTrial Haha yes it is! I’ll see if I can get round to that tonight/tomorrow morning.

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @draghafur @davidantibiotic @MerinoTrial pip/taz disk alone is probably enough and ignore the vitek, though the new Etest is probably better. Alternative: If susc by PTZ disk, CDDST confirms ESBL and amox/clav disk is susc, then sens and spec of 91.6% and 64.5% to exclude oxa strains

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @draghafur @davidantibiotic @MerinoTrial The main issue relates to the co-presence of OXA1 genes with ESBLs and the inability to differentiate the two using any phenotypic test. Reducing the susceptible breakpoint to <= 8mg/L as proposed by EUCAST does solve some issues, but still splits the OXA1/ESBL population.

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @draghafur @davidantibiotic @MerinoTrial

[Evan Bursle @evanbursle]

Association between minimum inhibitory concentration, beta-lactamase genes and mortality for patients treated with piperacillin/tazobactam or meropenem from the MERINO study https://t.co/L8dBdmKU2z

Nice work @Hendonet @padstamundo @davidantibiotic

[Patrick Harris @padstamundo]

This paper from @Hendonet @UQMedicine helps further our understanding of the @MerinoTrial - bottom line, MIC matters but so does the way you test and the #AMR genes that define the phenotype

[Jason Roberts @jasonroberts_pk]

Exciting webinar from ⁦@UQ_News⁩ & ⁦@CHUNimes⁩ on new advances in #antimicrobial susceptibility testing and reporting...stellar panel of Profs Turnidge, Lavigne & Kahlmeter. Thanks to ⁦@CRE_REDUCE⁩ ⁦@Hendonet⁩ ⁦@padstamundo⁩ hosted at #UQCCR

[David Paterson @davidantibiotic]

Out in CID - Association between minimum inhibitory concentration, beta-lactamase genes and mortality for patients treated with piperacillin/tazobactam or meropenem from the MERINO study @merinotrial @padstamundo https://t.co/yqX3cfcXr6

[CRE RESPOND @CRE_RESPOND]

Join Jason Roberts, Andrew Henderson, Jean-Philippe Lavigne, Gunnar Kahlmeter & John Turnidge for a webinar on antimicrobial susceptibility testing & hear from experts on the European Committee on AST (EUCAST). Please register here https://t.co/I1Spr6Io0b

[Adam Stewart @adm_stewart]

Our review in JAC on the use of oral 3GC/BLIs for ESBL urinary tract infections @davidantibiotic @padstamundo @Hendonet https://t.co/2c6e3KHgL3

[Andrew Henderson @Hendonet]

@evanbursle @padstamundo @padstamundo so good. Might need to do some editing again of your next infect control course lecture

[PA Hospital Brisbane @pahospital]

Safety and tolerability determined for monoclonal antibody treatment for #hendravirus in healthy human volunteers ~ Prof Geoffrey Playford @qldhealthnews @UQ_News #veterinaryscience #medicalresearch #clinicaltrials

[Antibiotic Steward Bassam Ghanem 🅱️C🆔🅿️🌟 @ABsteward]

NEW🔥🔥 Review Article @davidantibiotic @Hendonet @padstamundo
Current evidence for therapy of ceftriaxone-resistant Gram-negative bacteremia. #IDtwitter A must read article. #medtwitter ENJOY
https://t.co/xvTd5nTxwg

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @davidantibiotic @Hugh_Murray_ @syctong @Josh_S_Davis We also only looked at vitek S strains, but I think that is the question that clinicians are most interested in: if the vitek calls it susceptible, can the lab exclude penicillinase in order to confidently treat the patient with benzylpenicillin.

[Andrew Henderson @Hendonet]

https://t.co/IH9Qs54cwV. @padstamundo @davidantibiotic screening for Penicillinase in PSSA. Further proof for enrolling patients in PSSA BSI trials. @Hugh_Murray_ @syctong @Josh_S_Davis

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @davidantibiotic @Hugh_Murray_ @syctong @Josh_S_Davis We are sequencing all blaZ detected strains. There seemed to be two phenotypic distinct populations - disk size < 26 indicating an expressed penicillinase enzyme (perhaps slowly induced) and those with size > 26 in the WT distribution that might only express a basal amount.

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @davidantibiotic @Hugh_Murray_ @syctong @Josh_S_Davis Prevalence of penicillin susceptible by vitek in our region is about 12-14% depending on specimen site. Nitrocefin and disk testing seemed to perform equally for different vitek MICs but numbers start to get low when you stratify by this.

[Andrew Henderson @Hendonet]

@DrToddLee @padstamundo @davidantibiotic @Hugh_Murray_ @syctong @Josh_S_Davis All good points and lots of questions!
First thing - I have never seen a published case of penicillin failure for PSSA due to mis-identification of penicillin resistance. Several other drug-bug combos have as many issues with false susceptibility (if not more)