J Med Tech Assoc Thailand, Vol. 40 No. 3, December 2012 Original Article

Rapid Haemocultures Report

Sujitra Manakul* and Natthiya Inthachang

Clinical Microbiology Section, Medical Technology Department,Suratthani Hospital, Suratthani 84000 Thailand

AbstractSepticemia or sepsis refers to the presence of pathogenic organisms in the bloodstream

with related clinical symptoms causing death. Rapid and accurate identification of a causative

agent including antibiogram is, therefore, important. The objective of this study was to compare

the results of bacterial identification and antimicrobial susceptibility testing (AST) obtained

from the standard (18-24 hours incubation) and the modified (8 - 10 hours incubation) methods.

The experiment was performed with 90 bacterial isolates acquired from 89 hemoculture positive

samples from Surath-thani Hospital during April 2007 to June 2008. The results showed that

66 isolates (73.3%) were gram negative and 24 isolates (26.7%) were gram positive bacteria.

Identification of these bacteria by the standard and modified methods yielded the same results

for 64 isolates (97%) in gram negative and 23 isolates (95.8%) in gram positive bacteria.

McNemar statistical test revealed no significant difference (p 0.05) between the two

methods in term of identification, although the standard identification of one sample revealed

two bacterial species, Escherichia coli and Klebseilla pneumoniae, while the modified method

identified as Enterobacter aerogenes. Interestingly, AST of the standard and modified methods

gave identical results for 66 isolates (100%) in gram negative and 18 isolates (75%) in gram

positive bacteria. Statistical analysis of the AST showed significant difference between the two

methods (p 0.05). Our results suggest that the modified method can be applied in laboratory

to reduce the turnaround time for identification of both gram positive and gram negative

bacteria. However, this modified method is not suitable for mixed culture specimen. For the

AST, the modified method can be used only in gram negative bacteria.

Key words: Bacterial identification, Antimicrobial susceptibility testing (AST), Haemoculture

*Corresponding author E-mail address: sujitra2008@gmail.com

40 3 2555

(18-24 .) (8-10 .) 90 89 2550 - 2551 2 8-10 . 18-24 . 66 ( 73.3) 24 ( 26.7) 2 64 ( 97.0) 23 ( 95.8) McNemar Test 2 (p 0.05) E.coli K. pneumoniae E. aerogenes 66 2 66 ( 100) 24 18 ( 75.0) 2 (p 0.05) 8-10 .

*

84000

:

* E-mail address: sujitra2008@gmail.com

4302

(1,2)

(3)

(4)

(5)

2

8-10

18-24

90

BacT/Alert

89

2550- 2551

Gram stain

Blood agar (BA),

MacConkey (MAC) Chocolate agar (CA)

BA CA 5-10%

CO2 35 C MAC 35 C

8-10 .

BA, CA MAC 35 C

18-24 .

8 -10 .

18-24 .

4303

Vitek 2 Compact Gram positive

Gram positive identify card (GPI)

Gram negative Gram

negative identify card (GNI)

species (6)

Disc diffusion CLSI

(Clinical and Laboratory Standard Institute)

inhibition zone

CLSI(7)

susceptible (S), intermediate (I), resistant

(R)

control sensitivity discs

3 Staphylococcus aureus ATCC

25923, Escherichia coli ATCC 25922

Pseudomonas aeruginosa ATCC 27853

Amikacin, Ampicillin,

Augmentin, Cefuroxime, Cefotaxime, Ceftra-

zidime, Ceftriaxone, Ciprofloxacin, Ofloxacin,

Gentamicin, Cotrimoxazole, Levofloxacin,

Cefpirome, Netilmicin, Imipenem, Meropenem,

Ertapenem Sulperazone (

)

Staphylococcus spp.

Augmentin, Cephalothin, Cefuroxime,

Cotrimoxazole, Erythromycin, Clindamycin,

Gentamicin, Oxacillin Fosfomicin

Streptococcus spp.

Ampicillin, Augmentin, Cefuroxime, Chlor-

amphenicol, Erythromycin, Cotrimoxazole,

Clindamycin, Penicillin Vancomycin

McNemar Test

8-10 .

18-24 .

BacT/Alert 89

90

66

( 73.3) 24

( 26.7)

E. coli 27.8

K. pneumoniae 20.0,

Staphylococcus haemolyticus 7.8

Acinetobacter baumannii 6.7

( 1)

4304

8-10 .

18-24 .

97.0

95.8 ( 2)

1

S. haemolyticus Staphylococcus

epidermidis urease

E. coli K. pneumonia

E. aerogenes (

3) 8-10 .

1

McNemar Test

8-10

. 18-24 .

(p > 0.05) ( 4

5)

1 90 BacT/Alert 89 1824

( = 66)

( = 24)

Gram Negative 66 (73.3%) Gram Positive 24 (26.7%)

Escherichia coli

Klebseilla pneumoniae

Acinetobacter baumannii

Salmonella group D

Enterobacter cloacae

Proteus mirabilis

Pseudomonas aeruginosa

Plesiomonas shigelloidis

Salmonella group B

Serratia marcescens

Haemophillus influenzae

25(27.8%)

18(20.0%)

6(6.7%)

5(5.6%)

4(4.4%)

2(2.2%)

2(2.2%)

1(1.1%)

1(1.1%)

1(1.1%)

1(1.1%)

Staphylococcus epidermidis

Staphylococcus haemolyticus

Staphylococcus

coagulase positive

Streptococcus agalactiae

Staphylococcus sciuri

Staphylococcus uberis

Staphylococcus xylosus

Staphylococcus simulans

Streptococcus sanguinis

7(7.8%)

7(7.8%)

3(3.4%)

2(2.2%)

1(1.1%)

1(1.1%)

1(1.1%)

1(1.1%)

1(1.1%)

4305

2 8-10 18-24

(= 90)

Gram Negative* 66 64(97.0%) 2(3.0%)

Escherichia coli 25 24 1 indole, urease, citrate

Klebseilla pneumoniaeAcinetobacter baumannii Salmonella group DEnterobacter cloacaeProteus mirabilisPseudomonas aeruginosaPlesiomonas shigelloidis Salmonella group BSerratia marcescensHaemophillus influenzae

18654221111

17654221111

1000000000

motile

Gram Positive** 24 23(95.8%) 1(4.2%)

Staphylococcus epidermidisStaphylococcus haemolyticusStaphylococcus coagulase positive Streptococcus agalactiaeStaphylococcus sciuriStaphylococcus uberisStaphylococcus xylosusStaphylococcus simulansStreptococcus sanguinis

773

211111

763

211111

010

000000

urease

* McNemar Test p = .500** McNemar Test p = 1.000

4306

66 8-10 .

18-24 .

susceptible, interme-

diate, resistance

100 ( 4)

24

8-10 . 18-24

.

18

3 3 8-10 18 24

18 24 . 8-10 .

1 Staphylococcus haemolyticus Staphylococcus epidermidis

2 Escherichia coli Enterobacter aerogenes

Klebseilla pneumoniae

75.0

6 25.0

( 4) S. haemolyticus

3 S. agalactiae, S. uberis S.

simulans 1

CXM, CC, OX, E

AMC inhibition zone

( 5)

McNemar Test

8-10 . 18 -24

. (p < 0.05) ( 4)

4307

4 8-10 1824

(= 90)

Gram Negative 66 66(100%) 0(0%)

E. coliK. pneumoniaeA. baumanniiSalmonella group DE. cloacaeP. mirabilisPs. aeruginosaPle. ShigelloidisSalmonella group BS. marcescensH. influenzae

2518654221111

2518654221111

00000000000

Gram Positive* 24 18(75.0%) 6(25%)

S. epidermidisS. haemolyticusStaphylococcus coagulase positive S. agalactiaeS. sciuriS. uberisS. xylosusS. simulansS. sanguinis

773

211111

743

110101

030

101010

CXM, CC, OX

C, CC, E

C, CC, E

CXM, OX, AMC, E

CXM = Cefuroxime, CC = Clindamycin, OX = Oxacillin, C = Chloramphenicol,E = Erythromycin, AMC = Augmentin*McNemar Test p = 0.031

4308

8-10 . 18-24 .

89 90

66

24

E. coli

K. pneu-

moniae

8-10 .

64

5 6 8-10 18-24

Antimicrobial disc (inhibition zone diameter)

CXM CC OX AMC E

1 2 1 2 1 2 1 2 1 2

1 S. haemolyticus S I - - - - - - - -

2 S. haemolyticus - - S R - - - - -

3 S. haemolyticus - - S I S R - - - -

4 S. agalactiae - - S I - - - - S I

5 S. uberis - - S R - - - - S I

6 S. simulans S R - - S R S R S R

CXM = Cfuroxime, CC = Clindamycin, OX = Oxacillin, AMC = Augmentin, E = Erythromycin

S = susceptible, I = intermediate, R = resistance, 1 = 8-10

2 = 18-24

( 97)

23

( 95.8)

1 S. haemolyticus

S. epidermidis

urease

8-10 .

E. coli

K. pneumonia

E. aerogenes

4309

8-10 .

18-24 .

McNemar Test

8-10 .

18-24 .

(p > 0.05)

8-10 .

66

66

( 100)

24

18

( 75.0)

6 ( 25.0) S.

haemolyticus 3 S. agalactiae,

S. uberis S. simulans 1

CXM, CC,

OX, E AMC inhibition zone

8-10 .

inhibition zone

8-10 .

18-24 . (p < 0.05)

8-10 .

8-10 .

1

4310

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