diff --git a/bam2fastx.wdl b/bam2fastx.wdl
index 3cdb29fbd2230c87b1d97e578ec21bf3292d77cd..b09f7a0fb03f9deed29b68537e397dd2e88d3de9 100644
--- a/bam2fastx.wdl
+++ b/bam2fastx.wdl
@@ -111,7 +111,7 @@ task Bam2Fastq {
         -c ~{compressionLevel} \
         ~{true="--split-barcodes" false="" splitByBarcode} \
         ~{"--seqid-prefix " + seqIdPrefix} \
-        ~{bam}
+        ~{sep=" " bam}
     }
 
     output {