Antibiotic susceptibility of coagulase-negative staphylococci isolated from very low birth weight babies: comprehensive comparisons of bacteria at different stages of biofilm formation

Table 1 Bacterial isolates and growth media used for biofilm formation.

Isolate	Species	Status	Growth medium for biofilm formation^a
			TSB	TSB+1% glucose	TSB+4% NaCl	*icaA*	*icaC*	*icaD*
1	S. warneri	Invasive		+		-	-	-
2	S. haemolyticus	Invasive	-			-	-	-
3	S. epidermidis	Invasive	+			+	+	+
4	S. epidermidis	Invasive	+			-	-	-
5	S. epidermidis	Invasive	+			+	+	+
6	S. capitis	Invasive			+	+	+	-
7	S. epidermidis	Invasive	+			+	+	+
8a	S. capitis	Invasive			+	+	+	-
8b	S. capitis	Invasive			+	+	+	-
9	S. capitis	Invasive			+	+	+	-
10	S. epidermidis	Invasive		+		-	-	-
11	S. epidermidis	Invasive	+			+	+	+
12	S. epidermidis	Contaminant		w		-	-	-
13	S. epidermidis	Contaminant	+			+	+	+
15	S. capitis	Contaminant		w		+	+	-
16	S. capitis	Contaminant		+		+	+	-
17	S. capitis	Contaminant			+	+	+	-
18	S. capitis	Contaminant			+	+	+	-
19	S. epidermidis	Contaminant	-			-	-	-
20	S. epidermidis	Contaminant	+			+	+	+
21	S. epidermidis	Contaminant	+			+	+	+
22	S. capitis	Contaminant		w		+	+	+
23	S. epidermidis	Contaminant	+			+	+	+
24	S. epidermidis	Contaminant		+		+	+	+
RP62A	S. epidermidis	Reference	+
SP2	S. hominis	Reference	-

^a Selection of growth medium was based on the production of the highest biofilm density for each isolate. The amount of biofilm was indicated as: "+", strong (OD₆₀₀ ≥ 0.24); "w", weak (0.12≤ OD₆₀₀ <0.24); "-", negative (OD₆₀₀ <0.12). Isolates 8a and 8b were from the same baby, collected at different episodes of sepsis. Isolate 14 was not available for this study.

ISSN: 1476-0711