Streptococcus pneumoniae Oxacillin µg as screen for beta-lactam resistance Version 6. June
Streptococcus pneumoniae and zone diameter correlates The following histograms present inhibition zone diameter distributions from EUCAST antimicrobial susceptibility testing. In most, the different colours of the bars indicate different values. In some, the colours of the bars indicate a resistance gene or a resistance mechanism. The distributions include data for wild-type isolates and for isolates with acquired resistance mechanisms. A large number of isolates with values close to the edge of the wild-type distribution and/or close to EUCAST clinical breakpoints were intentionally included. These distributions can not be used to infer resistance rates or the performance of the tests with routine isolates. For some agents, isolates were tested on more than one occasion, including parallel tests with disks and media from several manufacturers. When this is the case, data are presented as both the number of isolates tested and the total number of -zone diameter correlates, including replicate tests and parallel tests with disks and media from different sources.
Streptococcus pneumoniae Materials and methods Antimicrobial susceptibility testing was performed on clinical isolates of Streptococcus pneumoniae, including isolates with known resistance mechanisms. Disk diffusion was performed on MH-F media according to EUCAST methodology and determination was performed with the ISO broth microdilution method using MH-F broth or gradient tests. The following graphs present inhibition zone distributions for oxacillin µg with values for beta-lactam agents as coloured bars. The distributions of vs. zone diameter in this presentation are mostly the result of a collaboration between EUCAST, JMI Laboratories (USA) and Laboratory Specialists Inc. (USA). This presentation is based on EUCAST Clinical Breakpoint Tables v...
Changes from previous version (5.) Changes Recommendations in meningitis added to flow chart.
Streptococcus pneumoniae Screen for beta-lactam resistance Disk diffusion test with oxacillin µg disk Zone diameter mm Zone diameter < mm* Report susceptible to all beta-lactam agents for which clinical breakpoints are available, including those with Note, except for cefaclor, which if reported, should be reported as intermediate. Benzylpenicillin* (meningitis) and phenoxymethylpenicillin (all indications) Benzylpenicillin (infections other than meningitis) Ampicillin, amoxicillin and piperacillin (without and with beta-lactamase inhibitor), cefepime, cefotaxime, ceftaroline, ceftobiprole and ceftriaxone Other betalactam agents Oxacillin zone mm Oxacillin zone < mm Report resistant Determine the and interpret according to the clinical breakpoints. Report susceptible** Determine the and interpret according to the clinical breakpoints. For ampicillin, amoxicillin and piperacillin (without and with beta-lactamase inhibitor) infer susceptibility from the of ampicillin. *Always determine the of benzylpenicillin. Do not delay reporting resistant in meningitis. ** In meningitis confirm by determining the for the agent considered for clinical use.
3 Explanation of graphs: Zone diameter distribution with values or resistance mechanisms as coloured bars. 7 6 5 Oxacillin µg vs. Ertapenem S. pneumoniae, isolates Zone diameter breakpoint Resistant by EUCAST breakpoints.5.5. Susceptible by EUCAST breakpoints.
3 7 6 5 Oxacillin µg vs. Benzylpenicillin S. pneumoniae, isolates ( data sources).5.5.. Benzylpenicillin (non-meningitis) S, R> mg/l mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Benzylpenicillin S. pneumoniae, isolates ( data sources).5.5.. Benzylpenicillin (meningitis) S, R> mg/l mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Ampicillin S. pneumoniae, 53 isolates ( data sources).5.5. Ampicillin S.5, R> mg/l mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Cefepime S. pneumoniae, isolates ( data sources).5.5. Cefepime Oxacillin zone diameter (screen) S, R> mg/l S mm
3 5 5 5 Oxacillin µg vs. Cefotaxime S. pneumoniae, 5 isolates ( correlates) ( data sources) 6.5.5.. Cefotaxime S.5, R> mg/l mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Cefpodoxime S. pneumoniae, isolates ( data sources).5.5. Cefpodoxime S, R>.5 mg/l.5 mg/l Oxacillin zone diameter (screen) S mm
3 7 Oxacillin µg vs. Ceftaroline S. pneumoniae, 5 isolates ( data sources) 6 5.5.5... Ceftaroline S, R> mg/l mg/l Oxacillin zone diameter (screen) S mm
3 7 Oxacillin µg vs. Ceftobiprole S. pneumoniae, 5 isolates ( data source) 6 5.5.5.. Ceftobiprole S.5, R>.5 mg/l mg/l Oxacillin zone diameter (screen) S mm
3 6 Oxacillin µg vs. Ceftriaxone S. pneumoniae, isolates ( data sources) 5.5.5.. Ceftriaxone S.5, R> mg/l mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Cefuroxime S. pneumoniae, 5 isolates ( data sources).5.5. Cefuroxime (iv) S.5, R> mg/l.5 mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Cefuroxime S. pneumoniae, 5 isolates ( data sources).5.5. Cefuroxime (oral) S, R>.5 mg/l.5 mg/l Oxacillin zone diameter (screen) S mm
3 Oxacillin µg vs. Doripenem S. pneumoniae, isolates ( data sources) 7 6 5.5.5... Doripenem S, R> mg/l. mg/l Oxacillin zone diameter (screen) S mm
3 7 6 5 Oxacillin µg vs. Ertapenem S. pneumoniae, isolates ( data sources).5.5.. Ertapenem S.5, R>.5 mg/l mg/l Oxacillin zone diameter (screen) S mm
3 Oxacillin µg vs. Imipenem S. pneumoniae, isolates ( data sources) 7 6 5.5.5... Imipenem S, R> mg/l. mg/l Oxacillin zone diameter (screen) S mm
3 6 Oxacillin µg vs. Meropenem S. pneumoniae, isolates ( correlates) (3 data sources).5.5... Meropenem (non-meningitis) S, R> mg/l. mg/l Oxacillin zone diameter (screen) S mm
3 6 Oxacillin µg vs. Meropenem S. pneumoniae, isolates ( correlates) (3 data sources).5.5... Meropenem (meningitis) S, R> mg/l. mg/l Oxacillin zone diameter (screen) S mm