Inactivation of Clinically Frequently Used Antimicrobial Agents By BacT/ALERT FAN Plus and BACTEC Aerobic and Anaerobic Culture Media in Simulated Blood Cultures: First Comparative Evaluation in China Mainland

Figures & data

Table 1 Microorganism and Antimicrobial Combinations Tested by the Simulated Adult Blood Culture Model

Species (Strain)	Antimicrobial	MIC (μg/mL)^a	Antimicrobial Concentration (μg/mL)^b
			Cmax	C/2	C/4
Gram-negative bacilli
Escherichia coli (ATCC 25922)	Imipenem	0.25	40	20	10
	Meropenem	0.06	50	25	12.5
	Cefoxitin	4	110	55	27.5
	Piperacillin-tazobactam	4	242/24	121/12	60.5/6
	Levofloxacin	0.06	8.6	4.3	2.15
Pseudomonas aeruginosa (ATCC 27853)	Imipenem	1	40	20	10
	Meropenem	0.25	50	25	12.5
	Piperacillin-tazobactam	4	242/24	121/12	60.5/6
	Levofloxacin	1	8.6	4.3	2.15
Bacteroides fragilis (ATCC 25285)	Imipenem	0.06	40	20	10
	Meropenem	0.06	50	25	12.5
	Piperacillin-tazobactam	0.25	242/24	121/12	60.5/6
Gram positive cocci
Staphylococcus aureus (ATCC 29213)	Vancomycin	0.5	50	25	12.5
	Linezolid	2	20	10	5
	Imipenem	0.03	40	20	10
	Meropenem	0.12	50	25	12.5
	Levofloxacin	0.12	8.6	4.3	2.15
Enterococcus faecalis (ATCC 29212)	Vancomycin	2	50	25	12.5
	Linezolid	2	20	10	5
	Levofloxacin	1	8.6	4.3	2.15
Yeast
Candida parapsilosis (ATCC 22019)	Voriconazole	0.03	3	1.5	0.75

Notes: Italicized text for genus and species name of microorganism. ^aMICs of the antimicrobial drugs for each strain tested were determined by CLSI broth microdilution and susceptibility categorization was assigned based on published CLSI breakpoints. ^bFor each antimicrobial tested, concentrations corresponding to the plasma peak (C_max), half (C/2), and quarter (C/4) levels are indicated.

Table 2 Recovery in Aerobic (BacT/Alert FA Plus and BACTEC Aerobic/F Plus) or Anaerobic (BacT/Alert FN Plus and BACTEC Lytic/10 Anaerobic) Bottles Containing Antibiotics by Microorganism

Strains	Recovery (%)
	BacT/Alert FA Plus	BacT/Alert FN Plus	BACTEC Aerobic/F Plus	BACTEC Lytic/10 Anaerobic
E. coli (ATCC25922)	16/45 (35.6)	21/45 (46.7)	11/45 (24.4)	5/45 (11.1)
P. aeruginosa (ATCC27853)	19/25 (76.0)	–	19/25 (76.0)	–
B. fragilis (ATCC25285)	–	15/15 (100.0)	–	0/15 (0.0)
S. aureus (ATCC29213)	19/25 (76.0)	25/25 (100.0)	15/25 (60.0)	10/25 (40.0)
E. faecalis (ATCC29212)	15/15 (100.0)	15/15 (100.0)	14/15 (93.3)	2/15 (13.3)
C. parapsilosis (ATCC22019)	5/5 (100.0)	–	5/5 (100.0)	–
Total	74/115 (64.3)	76/100 (76.0)	64/115 (55.7)	17/100 (17.0)

Note: Italicized text for genus and species name of microorganism.

Table 3 Times to Detection of Gram-Negative Bacillus Recovered from Resin-Containing BacT/Alert or BACTEC Aerobic (AE) and Anaerobic (AN) Media at Each Antimicrobial Concentration Tested in Blood Culture Quintuplicates

Strains and Antimicrobials	Concentration^a	BacT/Alert Plus Media						Bactec Media
		Recovery (No. of Replicates/Total)		Median TTD^b (h)		∆TTD^c (h)		Recovery (No. of Replicates/Total)		Median TTD^b (h)		∆TTD^c (h)
		AE	AN	AE	AN	AE	AN	AE	AN	AE	AN	AE	AN
E. coli
Imipenem	Cmax	0/5	5/5	>120	12.7	NA^d	0.5	0/5	0/5	>120	>120	NA	NA
	C/2	1/5	5/5	14.2	12.3	2.3	0.1	1/5	0/5	19.5	>120	8.1	NA
	None	5/5	5/5	11.9	12.2			5/5	5/5	11.4	10.2
Meropenem	Cmax	0/5	0/5	>120	>120	NA	NA	0/5	0/5	>120	>120	NA	NA
	C/2	0/5	0/5	>120	>120	NA	NA	0/5	0/5	>120	>120	NA	NA
	C/4	0/5	1/5	>120	15.4	NA	3.6	0/5	0/5	>120	>120	NA	NA
	None	5/5	5/5	11.4	11.8			5/5	5/5	11.6	10.0
Cefoxitin	Cmax	5/5	5/5	11.0	11.0	0.2	0.2	5/5	0/5	12.2	>120	0.6	NA
	None	5/5	5/5	10.8	10.8			5/5	5/5	11.5	10.0
Piperacillin-tazobactam	Cmax	5/5	5/5	11.6	12.7	2.1	2.4	5/5	5/5	13.9	13.7	3.0	3.6
	None	5/5	5/5	9.7	10.3			5/5	5/5	10.9	10.1
Levofloxacin	Cmax	1/5	0/5	17.3	>120	5.3	NA	0/5	0/5	>120	>120	NA	NA
	C/2	4/5	0/5	16.8	>120	4.8	NA	0/5	0/5	>120	>120	NA	NA
	None	5/5	5/5	12.0	11.8			5/5	5/5	11.3	9.8
P. aeruginosa
Imipenem	Cmax	5/5	-^e	18.4	-	2.1	-	5/5	-	19.6	-	2.1	-
	None	5/5	-	16.3	-			5/5	-	17.5	-
Meropenem	Cmax	1/5	-	23.0	-	6.5	-	0/5	-	>120	-	NA	-
	C/2	3/5	-	19.2	-	2.7	-	4/5	-	21.5	-	3.7	-
	None	5/5	-	16.5	-			5/5	-	17.8	-
Piperacillin-tazobactam	Cmax	5/5	-	15.8	-	−0.3	-	5/5	-	17.8	-	0.5	-
	None	5/5	-	16.1	-			5/5	-	17.2	-
Levofloxacin	Cmax	5/5	-	15.2	-	−0.6	-	5/5	-	17.5	-	0.2	-
	None	5/5	-	15.9	-			5/5	-	17.3	-
B. fragilis
Imipenem	Cmax	-	5/5	-	30.7	-	4.3	-	0/5	-	>120	-	NA
	None	-	5/5	-	26.4			-	5/5	-	21.6
Meropenem	Cmax	-	5/5	-	33.1	-	9.6	-	0/5	-	>120	-	NA
	None	-	5/5	-	23.5			-	5/5	-	25.1
Piperacillin-tazobactam	Cmax	-	5/5	-	32.6	-	0.9	-	0/5	-	>120	-	NA
	None	-	5/5	-	31.7			-	5/5	-	30.5

Notes: Italicized text for genus and species name of microorganism. ^aFor each antimicrobial tested, C_max, C/2, and C/4 concentrations are listed in Table 1. ^bFor each microorganism-antimicrobial combination tested, the median time to detection (TTD) was calculated by summing the TTDs of single blood culture replicates. TTD values are rounded to the nearest decimal. ^cFor each microorganism-antimicrobial combination tested, ΔTTD is the difference in TTD of the microorganism-antimicrobial-containing blood culture by that of the antimicrobial-free blood culture (antimicrobial-free control). ^dNA, not applicable (no microorganism growth in any bottle). ^eLack of data because the microorganism was cultured only in anaerobic (B. fragilis) or aerobic (P. aeruginosa or C. parapsilosis) bottles.

Abbreviations: AE, aerobic media; AN, anaerobic media.

Table 4 Times to Detection of Gram-Positive Coccus and Yeast Recovered from Resin-Containing BacT/Alert or BACTEC Aerobic (AE) and Anaerobic (AN) Media at Each Antimicrobial Concentration Tested in Blood Culture Quintuplicates

Strains and Antimicrobials	Concentration^a	BacT/Alert Plus Media						Bactec Media
		Recovery (No. of Replicates/Total)		Median TTD^b (h)		∆TTD^c (h)		Recovery (No. of Replicates/Total)		Median TTD^b (h)		∆TTD^c (h)
		AE	AN	AE	AN	AE	AN	AE	AN	AE	AN	AE	AN
S. aureus
Vancomycin	Cmax	5/5	5/5	14.6	21.4	1.6	0.8	2/5	0/5	22.4	>120	6.9	NA^d
	None	5/5	5/5	13.0	20.6			5/5	5/5	15.5	14.0
Linezolid	Cmax	5/5	5/5	14.8	22.1	0.6	3.4	5/5	5/5	19.8	17.5	3.9	3.3
	None	5/5	5/5	14.2	18.7			5/5	5/5	15.9	14.
Levofloxacin	Cmax	5/5	5/5	13.7	18.7	1.2	−0.3	5/5	5/5	16.1	19.3	2.7	4.1
	None	5/5	5/5	12.5	19.0			5/5	5/5	13.4	15.2
Imipenem	Cmax	2/5	5/5	22.9	19.4	4.3	0.0	1/5	0/5	21.7	>120	8.0	NA
	None	5/5	5/5	18.6	19.4			5/5	5/5	13.7	112.1
Meropenem	Cmax	2/5	5/5	22.5	25.0	1.7	3.4	2/5	0/5	19.7	>120	5.9	NA
	None	5/5	5/5	20.8	21.6			5/5	5/5	13.6	12.5
E. faecalis
Vancomycin	Cmax	5/5	5/5	13.5	14.9	1.1	0.3	4/5	2/5	19.7	20.4	4.8	6.5
	None	5/5	5/5	12.4	14.6			5/5	5/5	14.5	13.9
Linezolid	Cmax	5/5	5/5	11.5	20.6	0.2	1.9	5/5	0/5	11.8	>120	0.4	NA
	None	5/5	5/5	11.3	18.7			5/5	5/5	11.4	10.6
Levofloxacin	Cmax	5/5	5/5	12.5	20.0	0.0	0.3	5/5	0/5	11.5	>120	0.3	NA
	None	5/5	5/5	12.5	19.7			5/5	5/5	11
C. parapsilosis
Voriconazole	Cmax	5/5	-^e	32.2	-	−2.2	-	5/5	-	32.6	-	−0.1	-
	None	5/5	-	34.6	-			5/5	-	32.7	-

Notes: Italicized text for genus and species name of microorganism. ^aFor each antimicrobial tested, C_max, C/2, and C/4 concentrations are listed in Table 1. ^bFor each microorganism-antimicrobial combination tested, the median time to detection (TTD) was calculated by summing the TTDs of single blood culture replicates. TTD values are rounded to the nearest decimal. ^cFor each microorganism-antimicrobial combination tested, ΔTTD is the difference in TTD of the microorganism-antimicrobial-containing blood culture by that of the antimicrobial-free blood culture (antimicrobial-free control). ^dNA, not applicable (no microorganism growth in any bottle). ^eLack of data because the microorganism was cultured only in anaerobic (B. fragilis) or aerobic (P. aeruginosa or C. parapsilosis) bottles.

Abbreviations: AE, aerobic media; AN, anaerobic media.