Introducing the new face of CLSI M100 in 2023: An explanatory review.

BACKGROUND: The CLSI annual update of its M100 document is eagerly awaited every year. This year's update, the M100-Ed33, was published in February, and will significantly affect clinical practices. OBJECTIVE: To highlight and explain the rationale of the changes and their clinical impact. CONTENT: The major changes this year are mostly focused on PK/PD data, selective and cascade reporting of the antibiotics and therapy related comments. The CLSI has moved away from its classical grouping of antibiotics (A, B, U, O) to a tier-based approach (Tier 1, 2, 3, 4) which will aid in cascade reporting during an antibiotic susceptibility testing (AST). Rather than non-fastidious, fastidious and anaerobe grouping, the tables have been made organism specific. The aminoglycosides breakpoints have been changed for both Enterobacterales and Pseudomonas aeruginosa while for P. aeruginosa, the breakpoints of piperacillin - tazobactam (TZP) are also updated. These updates are mostly based on attainment of drug plasma level for bacterial stasis rather than bactericidal effect of the antibiotics. It is noteworthy, that these breakpoint changes are made, keeping in view that the aminoglycosides for all organisms should be used in combination therapy. For P. aeruginosa, gentamicin has been removed, while amikacin has been restricted for urinary isolates only.

Case Series and Mini-Review on Elizabethkingia meningoseptica, A high Alert Organism Causing Meningitis in Premature Neonates from A Tertiary Care Hospital of Western Rajasthan.

BACKGROUND: Elizabethkingia meningoseptica is a ubiquitous organism rarely associated with human diseases, but its association especially among hospitalized premature neonates and immunocompromised individuals are not so common. CASE: We report two cases of neonatal bacteraemia and meningitis among low birth weight premature neonates admitted in neonatal intensive care units (NICU) by E. meningoseptica, a high alert organism associated with such conditions. CONCLUSIONS: E. meningoseptica, a high alert organism associated with meningitis among premature underweight neonates. High degree of resistant to most of the broad-spectrum antibiotics makes its management a challenging task. A good communication between the clinician and the microbiologist becomes very important for the proper management of the patients.