(a) A county with a population of 372,000 to 410,000 shall conduct a biennial independent audit of all books, records, and accounts of each district, county, and precinct officer, agent, or employee, including those of the regular county auditor, and of all governmental units of the county hospitals, farms, and other institutions. The audit must cover all matters relating to the fiscal affairs of the county. The audit shall be conducted in each even-numbered year and must be completed before December 31 of the year.
(b) The commissioners court of the county shall employ a disinterested, competent, experienced public accountant or certified public accountant to perform the audit. The court shall enter a contract for the audit at the first regular meeting of the court in January of each even-numbered year. The consideration specified in the contract shall be paid from the general fund of the county.

(c) This section does not prevent a county from conducting an annual independent audit of the records covered by this section. If a county conducts annual independent audits and completes the audits before December 31 of each year, those audits constitute compliance with the requirements of this section.
(d) The audit required under this section is in addition to any special audit prepared under Subchapter C or to any regular or special audit report prepared by the regular county auditor.