Exhibit 32

CERTIFICATIONS UNDER SECTION 906

Pursuant to section 906 of the Sarbanes-Oxley Act of 2002 (subsections (a) and (b) of section 1350, chapter 63 of title 18, United States Code), the undersigned officer of Spero Therapeutics, Inc., a Delaware corporation (the “Company”), does hereby certify, to such officer’s knowledge, that:

The Quarterly Report for the quarter ended March 31, 2025 (the “Form 10-Q”) of the Company fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, and the information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Company.

 

Dated: May 13, 2025	/s/ Esther Rajavelu
	Esther Rajavelu
	President, Chief Executive Officer, Chief Financial Officer and Treasurer
	(Principal Executive Officer, Principal Financial Officer and Principal Accounting Officer)