diff --git a/locust_plugins/mongoreader.py b/locust_plugins/mongoreader.py
index a2242d2..c5a64d1 100644
--- a/locust_plugins/mongoreader.py
+++ b/locust_plugins/mongoreader.py
@@ -34,9 +34,10 @@ def __init__(
 
         """
         self.timestamp_field = timestamp_field
-        self.coll: Collection = (
-            coll or MongoClient(env["LOCUST_MONGO"])[env["LOCUST_MONGO_DATABASE"]][env["LOCUST_MONGO_COLLECTION"]]
-        )
+        if not coll:
+            self.coll: Collection = MongoClient(env["LOCUST_MONGO"])[env["LOCUST_MONGO_DATABASE"]][env["LOCUST_MONGO_COLLECTION"]]
+        else:
+            self.coll = coll
         self.cursor: Cursor = self.coll.find(filter, sort=[(self.timestamp_field, 1)])
         records_in_buffer = self.cursor._refresh()  # trigger fetch immediately instead of waiting for the first next()
         if not records_in_buffer: