Bacterial Contamination of Blood and Blood Products at Mbarara Regional Blood Bank in Rural South Western Uganda

doi:10.4236/aid.2013.33030

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Advances in Infectious Diseases, 2013, 3, 205-209

http://dx.doi.org/10.4236/aid.2013.33030 Published Online September 2013 (http://www.scirp.org/journal/aid) 205

Bacterial Contamination of Blood and Blood Products at

Mbarara Regional Blood Bank in Rural

South Western Uganda

G. B. Matte Aloysius1,2*, Bazira Joel1, Richard Apecu2, Boum Yap II3, Frederick Byarugaba1

1Department of Microbiology, Faculty of Medicine, Mbarara University of Science and Technology (MUST), Mbarara, Uganda;

2Department of Medical Laboratory Science, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda.

3Epicentre Mbarara Research Base, Mbarara, Uganda;

Email: *[email protected]

Received July 9th, 2013; revised August 7th, 2013; accepted August 16th, 2013

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

Background: Screening blood donors has practically eliminated viral and bacterial pathogens in blood used for trans-

fusion. However, transfusion-associated bacterial sepsis remains an important health-care concern and the commonest

cause of transfusion-related fatality in resource limited settings. Data on bacterial contamination of blood are scarce

while the demand of blood transfusion is continuously growing. Therefore we conducted a study to determine the

prevalence and typ e of bacterial con tamination in donor blood and bloo d produ cts, at the Mbarara Regio nal Blood Ban k.

Methodology: A total of 510 units of screened blood and blood products consisting of refrigerated whole blood and

packed cells were randomly sampled following aseptic procedures from Mbarara Regional Blood Bank. Two samples

from each unit were collected in universal containers containing Brain Heart Infusion Broth and incubated at 37˚C for

up to 7 days. Subcultures were carried out on Blood agar, Chocolate agar and MacConkey agar. Isolates were identified

by standard microbiologic techniques and drug susceptibility testing was performed by Kirby Bauer disc diffusion

method. Results: Of the 510 samples collected between June and October 2012, 18 (3.5%) samples showed growth.

The contaminants were Staphylococcus aureus 17/18 (94.4%) and Streptococcus viridans 1/18 (5.6%). Isolates were

sensitive to erythomycin, ampicillin, chloramphenicol and ciproflox acin and resistant to penicillin and cloxacillin. Con-

clusion: Blood and blood products from Mbarara Regional Blood have unacceptable levels of bacterial contamination

that can affect patient safety especially in an area with high malaria endemicity. Therefore it is critical to improve hy-

giene precautions in order to minimize bacterial contamination and ensure patient safety.

Keywords: Bacterial Contamination; Blood/Blood Products; Staph ylococci

1. Introduction

Blood transfusion is a medical intervention intended to

provide safe blood or blood components in a cost effec-

tive way to patients who require blood and/or blood

products. However, blood and blood components for

transfusion can be a source of infection to recipients

arising from contamination of these products by a variety

of transmissible agents. Since the 1980’s when the hu-

man immunodeficiency virus (HIV) was recognized,

rigorous screening of blood before it is supplied to re-

cipients was instituted and accepted worldwide [1].

Uganda adopted this rigorous screening of blood in order

to provide safe blood to her population. Blood is

screened for viruses including the Human Immunodefi-

ciency virus (HIV), Hepatitis B virus (HBV), Hepatitis C

(HCV) and for Treponema pallidum, a bacterium. It has

been documented that bacteria can cause morbidity and

mortality from blood and blood transfusion components

[2,3].

In developed countries, transfusion of blood and blood

components has a low but known infectious risk for pa-

tients and remains a threat [4,5]. In the United States,

bacterial contamination is said to account for 15.9% of

all transfusion related fatalities, and is considered the

second commonest cause of death from blood transfusion

after clerical errors [4,6]. Recent data indicate that bacte-

rial contamination has declined by about 50% or more

*Corresponding a uthor.

Bacterial Contamination of Blood and Blood Products at Mbarara Regional

Blood Bank in Rural South Western Uganda

206

with contamination being detected in about one in 5000

apheresis platelet concentrates tested [3,7]. The possibil-

ity and problem of bacterial contamination of blood and

blood products have received very little attention on the

African continent [3]. Few countries in Africa have pub-

lished records of bacterial contamination of blood/blood

products. These include Ghana [2,8], Kenya [9] and, Ni-

geria [3]. Many African countries do not have docu-

mented reports on bacterial contamination of blood and

blood products and no record whether these products do

pause a risk of causing morbidity and mortality among

recipients [3]. To the best of our knowledge, in Uganda,

no research has been carried out to determine blood

transfusion-associated infections or whether the blood

and blood components intended for transfusion may be

contaminated with bacteria. Therefore we performed this

study to determine the prevalence of bacterial contami-

nation of blood and blood products supplied by the

Mbarara Regional Blood Bank, identify the types of

contaminating bacteria and determine their antibiotic

susceptibility pattern.

2. Materials and Methods

This was a descriptive cross-sectional study conducted at

the Mbarara Regional blood Bank located in the South

Western Region of Uganda. A total of 510 samples of

blood were collected from blood donors between June

and October 2012 and were selected using non probabil-

ity convenient sampling. Blood and blood products in-

cluded in this study were those that had been screened

and found negative for Human Immunodeficiency virus,

Hepatitis B virus, Hepatitis C virus and Treponema pal-

lidum and had been stored for not more than 35 days.

2.1. Blood and Blood Product Collection from

Blood Bag Units

Blood bags were conveniently sampled. Refrigerated

stored blood in bags was thoroughly mixed, and the tub-

ing was then swabbed with 70% ethanol pads and a ster-

ile syringe was used to withdraw blood from the blood

bag through the line and some of the mixed blood from

the main bag was allowed to seep into the line. About

five milliliters were withdrawn by use of a 5-ml sterile

syringe and 2.5 ml transferred to each of the two Uni-

versal bottles containing the Brain Heart Infusion (BHI)

broth. The end of each line was then sealed to prevent

blood in the line and air from flowing back into the main

bag. Two seals were made, one before the punctured site

to prevent blood from flowing back to the main blood

bag, and the other after the puncture site. The BHI blood

culture bottle cover was then sterilized by flaming b efore

and after inoculation.

The two BHI sample suspensions were incubated at

37˚C and observed daily for any possible signs of bacte-

rial growth (pellicle formation, hemolysis, or turbidity)

for 7 days. Samples found with bacterial growth were

sub cultured using a sterile wire loop-full of each sample

onto blood agar, Chocolate agar and MacConkey agar

plates. Samples were incubated overnight (18 - 24 hours)

at 37˚C. A blind sub culture was performed for samples

which showed no growth on the seventh day. Any bacte-

rial growth was identified using colonial morphology,

Gram stain reaction, and standard biochemical reactions.

2.2. Antibiotic Susceptibility Testing

Antibiotic susceptibility testing was performed by the

Kirby Bauer disc diffusion method [10]. The following

antibiotic discs were used: ampicillin (10 µg), penicillin

(10 µg), chloramphenicol (10 µg), cloxacillin (5 µg),

ciprofloxacin (5 µg), erythromycin (15 µg), and inter-

preted according to the Clinical and Laboratory Stan-

dards Institute [11] guidelines.

2.3. Quality Control

Aseptic techniques were observed at all times during the

collection of the samples. Standard operating procedures

were employed throughout the whole investigative proc-

ess including use of standard Staphylococcus aureus

(ATCC 25923) for Gram-positive organisms. Standard

materials supplied by accredited manufacturers were

used in the study.

3. Results

Of the 510 blood and blood products, 18 units had bacte-

rial growth, indicating a 3.5% prevalence of bacterial

contamination of blood/blood products at the Mbarara

Regional Blood Bank. However, the level of contamina-

tion was higher in packed cell units than in whole blood

(see Table 1).

The majority of isolates 17/18 (94.4%) were Gram

positive, coagulase positive Staphylococcus aureus,

while Gram positive Streptococcus viridans contributed

1/18 (5.6%) of the contamination (see Table 2).

The S. aureus isolates showed a high sensitivity to

ampicillin, chloramphenicol, erythromycin and cipro-

Table 1. Level of contamination according to blood compo-

nent.

Type of blood componentGrowth

(n%) No growth

(n%) Total

(n%)

Whole blood 8 (2.5) 309 (97.5) 317 (100)

Packed cells 10 (5.2) 183 (94.8) 193 (100)

Total 18 (3.5)

492 (96.5) 510 (100)

Bacterial Contamination of Blood and Blood Products at Mbarara Regional

Blood Bank in Rural South Western Uganda 207

Table 2. Level of contamination according to type of bacte-

ria.

Bacteria type Number of blood units contamina te d

Bacteria type Whole blood Packed cells Total

S. aureus 8 9 17 (94.4%)

S. viridans 0 1 1 (5.6%)

Total 8 10 18 (100%)

floxacin. A high resistance of these strains to peniciliin

and cloxacillin was observed (see Figure 1). The S. viri-

dans isolated in one unit of packed cells showed resis-

tance to penicillin and cloxacillin and was sensitive to

chloramphenicol, ampicillin, ciprofloxacin, and erythro-

mycin (data not shown).

Highest resistance to Penicilin and cloxacillin and

lowest resistance to Erythromycin was observed.

4. Discussion

The prevalence of bacterial contamination of blood/blood

products of 3.5% found in this study is lower compared

to other studies carried out in Africa—7% in Kenya, [9],

8.8% in Nigeria, [3] and between 9 to 17.5% in Ghana,

[2,8]. This could be explained by the difference in the

settings across the countries and the time since the im-

plementation of rigorous regulations on blood products.

The prevalence of blood contamination in this study is

however higher than that reported in developed countries.

In the United States, a prevalence of 0.2% was reported

[12], while 0.15% was reported in the UK [13], and 0.1%

was reported in France [14]. The explanation for lower

prevalence in developed countries is attributed to more

rigorous screening procedures practiced in these coun-

tries.

Nonetheless it should be noted that despite the lower

prevalence in developed countries, severe annual mor-

bidity and mortality due to bacterial contamination of

blood is considered a cause of significant annual morbid-

ity and mortality [4]. No follow up studies have been

carried out in patients transfused with contaminated

blood to determine the level of morbidity and mortality

in Uganda. Moreover, these data could explain the fever

observed usually 5 days after blood transfusion of chil-

dren treated for severe episodes of malaria in our hospital

(Unpubli shed data).

The organisms isolated in this study were Staphylo-

coccus aureus and Streptococcus viridans. In Ghana, the

isolates reported by a study conducted by Adjei were

Gram-positive bacteria (S. aureus, Coagulase-negative

Staphylococci (CNS), and Bacillus species) and

Gram-negative bacteria (Y. enterocolitica, Citrobacter

freundii, E. coli, P. aeroginosa, and Klebsiella pneumo-

niae) [8]. Opoku-Okrah also in Ghana reported only

Figure 1. Sensitivity patterns of S. aureus to various antibi-

otics (n = 17).

Gram-positive bacteria which included coagulase nega-

tive Staphylococci, Staphylococcus aureus, Corynebac-

teria. The Gram-negative bacteria identified included E.

coli, bactero ides an d Klebsiella pneumonia [2]. A similar

study conducted in Nigeria reported Gram-positive bac-

teria (S. aureus, CNS, Bacillus spp, Listeria spp) to have

been isolated [3]. In Kenya, the isolates included

Gram-negative organisms (Acinetobacter spp., Aeromo-

nas spp., Brevundemonas vescularis, Burkholderia ce-

pacia, Enterobacter sekazaki, Klebsialla pneumonia,

Ochrobacterum anthropi, Oligella urethralis, Pseudo-

monas spp., Rhizob ium radiobacter, Shewanella putrefa-

ciens) and Gram-positive bacteria (Ba cillus spp., Micro-

coccus spp.,and Staphylococcus epidermidis) [9]. In the

BACON, SHOT, and BACTHEM studies carried out in

the United States, UK, and France respectively, Brecher

and Hay, reported the following Gram-positive bacteria

isolated from red cells implicated in transfusion-associ-

ated infections (CNS, Streptococcus spp., Staphylocco-

cus aureus, Enterococcus feacalis, Bacillus cereus,

Propionibacterium acnes,) and Gram-negative bacteria

(Serretia liquifaciens, Serratia marcescens, Yersinia en-

terocolitica, Enterobacter spp., Acinetobacter spp.,

Pseudomonas spp., E. coli, Klebsiella pneumonia, and

Proteus miribalis) [15]. The Staphyloccocus aureus and

Streptoccocus viridans isolated in this study are part of

the skin normal flora and therefore can easily be intro-

duced in the blood if skin disinfection is not performed

properly duri n g bl eeding process.

All isolated organisms in this study showed varying

susceptibility to the tested antibio tics as indicated in Fig-

ure 1. The S. aureus organisms showed resistance to

commonly used antibiotics including penicillin, cloxacil-

lin, chloramphenicol, ampicillin, ciprofloxacin and

erythromycin. The S. viridans isolated showed resistance

to penicillin and cloxacillin and was sensitive to

chloramphenicol, ampicillin, ciprofloxacin and erythro-

mycin. The resistance to cloxacillin and penicillin might

be due to these organisms ability to produce beta lac-

tamases (penicillase) that destroy the B-lactam ring

Bacterial Contamination of Blood and Blood Products at Mbarara Regional

Blood Bank in Rural South Western Uganda

208

found in these antibiotics, rendering the antibiotics inef-

fective. In Ghana, it was reported that all Gram-positive

isolates were resistant to cefuroxime, penicillin, ampicil-

lin, and cotrimoxazole but sensitive to cefotoxime, tetra-

cycline, erythromycin, and gentamycin [2,8]. Similarly,

all the Gram-negative organisms isolated were resistant

to cefotoxime (except Y. enterocolitica), tetracycline,

ampicillin, cefuroxime, cotrimoxazole, and chloram-

phenicol but sensitive to amikacin and gentamycin. A

study in Nigeria reported resistance to antibiotics tested

(ampicillin, cotrimoxazile, erythromycin, penicillin, tet-

racycline, rifampicin) except gentamycin, and ceftri-

oxone that ranged from 50% to 100% [3].

One possible explanation for the high resistance of

donor blood isolates may be associated with the ease of

procuring antibiotics over the counter in Uganda, self

medication, and shortfalls in infection control [16]. An-

other possible cause of high resistance could be due to

misuse of antibiotics by cattle farmers, Amanya, (unpub-

lished) reported bacterial resistance to antibiotics on

bacteria isolated from milk which included S. aureus,

Klebsiella pneumonia, S. agalactiae, and E. coli which

showed resistance to the commonly used antibiotics in-

cluding tetracycline, gentamycin and penicillin. This can

imply that people consuming milk and milk products

may acquire bacterial strains from milk and milk prod-

ucts that are already resistant to the commonly used anti-

biotics.

5. Conclusion

Bacterial contamination of blood was found to be 3.5%.

Staphylococcus aureus was found to be the major con-

taminant with 17 out of 18 organisms isolated (94.4%)

while Streptococcus viridans contributed 1/18 (5.6%).

The isolates are known to be part of the skin normal flora.

The organisms showed increased resistance to penicillin

and cloxacillin but susceptible to ampicillin, chloram-

phenicol, erythromycin and ciprofloxacin.

6. Recommendation

While the Mbarara Regional Blood Bank is doing a

commendable job in provision of safe blood and blood

products emphasis should be put on ensuring proper dis-

infectio n o f phlebotomy site s .

Policy makers should ensure emphasis of blood safety

during phlebotomy by providing quality disinfectants.

Routine antibiotic susceptibility testing is recommended

in all cases of post-transfusion sepsis.

7. Acknowledgements

We appreciate the financial, material and moral support

offered to us by Mbarara University of Science and

Technology, Department of Microbiology and; Epicen-

tre Mbarara Research Base. Special thanks to Dr. At-

wine Daniel of Epicentre for the support towards the data

analysis of our study .

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