Advantages and Limitations of Direct PCR Amplification of Bacterial 16S-rDNA from Resected Heart Tissue or Swabs Followed by Direct Sequencing for Diagnosing Infective Endocarditis: A Retrospective Analysis in the Routine Clinical Setting

Table 2

Overview of PCR results and preoperative antibiotic treatment. Crude numbers refer to number of patients; numbers in parentheses indicate the proportion of valve tissue samples versus swabs.

Tissue samples/swabs^1
		Number of patients	PCR
			Positive	Negative
Total		114	40 (28/12)	74 (42/32)
⁢Preoperative antibiotic treatment		101	33 ND 7	68 ND 4
IE	Definite	100	36 (25/11)	64 (35/29)
	Possible	4	4 (3/1)	0
	No evidence	10	0	10 (7/3)

ND: no data available; for 2 patients a preoperative antibiotic treatment could be excluded by medical chart.
¹Positive tissue/swab cultures were available for 11 specimens that were exceptionally analyzed using broad-range PCR before a negative culture result was obtained. These data were described but not used for the computation of sensitivity, specificity, and positive and negative predictive values of broad-range PCR.