Asymptomatic Bacteriuria among Type 2 Diabetics in the Sekondi-takoradi Metropolis, Ghana
Samuel A. Sakyi,
Richard K.D. Ephraim,
Bastu O. Adebisi,
Type 2 diabetes mellitus (T2DM) is associated with several overt and covert complications. The objective of this study was to establish the prevalence of Asymptomatic Bacteriuria (ASB), Antimicrobial Sensitivity pattern of the bacterial isolates and associated confounding factors leading to ASB in the Sekondi-takoradi metropolis. A cross-sectional, non-probability sampling technique was used to recruit 102 confirmed Type 2 diabetes mellitus and 23 healthy controls. Fasting blood samples were collected from both study and control participants for blood sugar analysis, midstream urine for microscopy, culture and Antibiotic Sensitivity Testing (AST). Total prevalence of ASB in this study was 26.4 with 41.9% of the total prevalence found in participants with 6-10 years of diabetic history yielding a comparative significant difference in ASB in patients with longer diabetic duration. E. coli was the most prevalent bacterial isolate (15.6%) and the most resistant (62.5-100%). Tetracycline and cotrimoxazole were the least effective drugs (0%) whilst nitrofurantoin, nalidixic and gentamicin were more effective. The peak incidence of ASB in T2DM occurs within age group 50-59 years and more frequently in female diabetics. T2DM patients significantly have abnormal Body Mass Index (BMI) (p = 0.0022). Age, sex and BMI predispose T2DM patients to prevalence of ASB with highly resistant isolates in the Sekondi-Takoradi metropolis. These must be factored in the treatment of T2DM complications.
Received: January 28, 2013;
Accepted: March 18, 2013;
Published: May 21, 2013
Diabetes mellitus is an endocrine disorder associated with micro and macro
vascular complications. Additionally, diabetes are more susceptible to infections
like Urinary Tract Infections (UTI) as the high glucose concentration in the
urine of diabetics serves as a culture medium for pathogenic organisms (Carton
et al., 1992; Pozzilli and Leslie, 1994). UTI
in diabetics has always been associated with serious kidney infections such
as renal papillary necrosis, emphysematous cystitis and pyelonephritis (Nicolle,
UTI can be asymptomatic or symptomatic but as to which one takes precedence
is still a matter of debate (Alebiosu et al., 2003).
Asymptomatic bacteriuria (ASB) is known to be higher in diabetics than non-diabetics
(Zhanel et al., 1991). A number of risk factors
including age, sexual intercourse and duration of diabetes have been mentioned
The prevalence of ASB ranges from 29% by Geerlings et
al. (2000) in 639 diabetics, to 16.5% by Alebiosu
et al. (2003) in South-west Nigeria. To date the prevalence of ASB among
the Ghanaian diabetic population is unknown. This study therefore seeks to establish
the prevalence of ASB, antimicrobial sensitivity patterns of isolates and to
determine confounding factors in type 2 diabeties (T2DM) and ASB in the Sekondi-Takoradi
MATERIALS AND METHODS
Study area/study design: The study was undertaken at Effia-Nkwanta Regional Hospital (ENRH), Sekondi-takoradi, capital of the Western region of Ghana, the main referral medical facility serving that part of the country and surrounding regions between November, 2011 to May 2012. A cross-sectional non-probability sampling method was adopted (T2DM patients coming first at the laboratory irrespective of sex and aged 20 years and above were recruited) after their consent had been sought.
Study population: A total of 125 participants made up of 102 confirmed T2DM under routine clinical review and 23 healthy controls were recruited from the diabetic clinic and the OPD of the ENRH respectively. T2DM and control patients not being treated for any infection and not on antibiotics were included whilst pregnant women and unconfirmed diabetics with elevated sugar levels were excluded.
Ethical consideration: Ethical clearance was sought for and granted
by the ethics and research committees of the ENRH and UCC. Permission was also
obtained from the administrators of the hospital before the study begun. Furthermore,
all the participants after thorough explanation of the rationale of the study
agreed to a written informed consent and were recruited into the study. All
procedures followed were in accordance with the ethical standards of the Ministry
of Health, Ghana as well as the Helsinki Declaration of 1975.
Collection of blood and urine samples: After an overnight fast (8-12 h) about 2 mL of venous blood was collected into fluoride oxalate bottles, centrifuged at 1500 g for 5 min and stored at -180°C until assayed.
Using sterile, dry, wide necked, leak proof screw capped containers, midstream urine (MSU) specimen were collected for urinalysis, microscopy, culture and sensitivity. The specimens were refrigerated immediately and cultured within 2 h.
Fasting blood sugar (FBS): The plasma glucose were measured for each of the samples using the chemistry analyzer Selectra Junior (Vital Scientific, The Netherlands).
Urine culture and sensitivity (C/S): A loopful (0.002 mL) of well mixed urine sample was taken from each case using a standard calibrated loop and inoculated on a Cysteine Lactose Electrolyte-Deficient (CLED) agar. This was incubated aerobically at 37°C for 18 -24 h in an IPF 400 Precision incubator (Memmert, Germany).
Identification and counting of bacterial isolates: Bacterial colonies
were identified based on their colonial morphology (color, growth size and growth
pattern). Standard biochemical tests including citrate, urease, indole, catalase
and coagulase tests were used for further identification. The product of the
loop volume and the colony count (on CLED) gave the bacterial count. Bacterial
count >1x105 CFU mL-1 was considered significant whilst
a bacterial count of between 1x104-105 CFU mL-1
was considered as doubtfully significant. Bacterial count <1x104
CFU mL-1 was considered insignificant (Harding
et al., 2002).
Antimicrobial susceptibility test (AST): The Kirby Bauer method (Bauer
et al., 1966) was used to determine the susceptibility of the isolates
to selected antimicrobial agents. Antibiotic-impregnated paper discs (Medical
wire and Equipment Co. Ltd., Potley Corsham, England) containing the following
antibiotics: nalidixic acid (NAL, 30 μg), gentamicin (GEN, 10 μg),
tetracycline (TET, 30 μg), nitrofurantoin (NIT, 15 μg), cotrimoxazole
(COT, 25 μg), ampicillin (AMP, 10 μg), cefuroxime (CRX, 30 μg)
and pipemedic acid (PPA, 30 μg), were used. Fresh isolates of pure colonies
were emulsified in peptone water using a sterile straight wire loop and the
turbidity was adjusted to the equivalent of 0.5 McFarlands standard. A
portion of the emulsified suspension was obtained using a sterile cotton swab
and a three dimensional streak was made on a Mueller Hinton agar plate. A sterile
cotton swab was then used to obtain a portion of the emulsified suspension to
make a three- dimensional streak on a Mueller Hinton agar plate. Based on the
organisms Gram reaction an appropriate antibiotic disc was placed on the
plated ager within 15 mins of seeding and then incubated at 37°C overnight
(18-24 h). A caliper was used to determine the zone of inhibition which was
then compared to a standard chart to determine susceptibility categorized as
sensitive or resistant as previously described by Tagoe
and Desbordes (2012). A Gram negative-organism Escherichia coli (NCTC
10418) and Staphylococcus aureus [National collection of type cultures
(NCTC) 6571] a Gram-positive organism, were used as controls.
Statistical analysis: GraphPad Prism version 5.00 for windows was used
for statistical analysis (GraphPad software, San Diego California USA, www.graphpad.com).The
results were expressed as Means±SEM. Unpaired t-test was used to compare
mean values of continuous variables and χ2 was used to compare
discontinuous variables. Odds ratio (OR, s) (with 95% CI) was calculated using
chi-square statistical analysis.
Demographic and clinical features of diabetics: General characteristics
of study population are shown in Table 1. Participants with
ASB were older, had higher BMI, higher FBS and urine glucose levels compared
to the controls (p<0.05). The prevalence of ASB was higher in the diabetic
participants compared to controls though not significant (p = 0.0613). The male
diabetic participants were older compared to the females (p = 0.0031) whereas
the females were more obese compared to the males (p = 0.0063). The prevalence
of ASB was higher in the females compared to the males though not significant
(p = 0.4613).When the diabetics with ASB were compared to those without ASB,
diabetics with ASB had a longer duration of diabetes compared to their counterparts
without ASB (p = 0.009).
Age and sex distribution of ASB among diabetic participants: Table 2 shows the age and sex distribution of ASB among participants with diabetes. The peak incidence of ASB in males is in the sixth, seventh and eighth decade of life. In the females however, the peak incidence is found in the fourth decade of life. For the total diabetic population the peak incidence was found in the fifth decade of life.
Frequency of bacteria isolated from the urine of study participants: Table 3 represents the frequency of various bacteria isolated from the urine of study participants. E. coli were the most prevalent (15.6%) whereas E. faecalis, P. aeroginosa and C. freundii were the least prevalent (0.9%) in the diabetics with ASB. Gender wise, E. coli was more prevalent in females (16%) than in males (14.8%).
Prevalence of ASB in relation to glycaemic control: The prevalence of ASB in relation to glycaemic control is shown in Table 4. Twenty-five (30.8%) of the 81 participants with poor glycaemic control had ASB compared to 6/21 (28.6%) of subjects with good glycaemic control (p = 0.840).
The odds of developing ASB is the same in the good glycaemic and poor glycaemic groups (OR = 1.116; 95% CI = 0.3875-3.215).
|| General characteristics of study participants
|Data is expressed as Mean±SEM, BMI: Body mass index,
ASB: Asymptomatic bacteriuria, PC: Pus cells, EC: Epithelial cells, FBS:
Fasting blood glucose, HPF: High power field
|| Prevalence of bacterial isolates from both controls and diabetics
|CON: Coagulase negative staphylococcus
|| Age and sex distribution of diabetics with ASB
|| Prevalence of bacteriuria in relation to blood glucose control
|| Antimicrobial sensitivity pattern of bacterial isolates of
diabetics with ASB
|ASB: Asymptomatic bacteriuria, NAL: Nalidixic acid, NIT: Nitrofurantoin,
GEN: Gentamicin, TET: Tetracycline, CRX: Cefuroxime, PPA: Pipemidic acid,
COT: Cotrimoxazole, AMP: Ampicillin
Participants with 6-10 years of diabetic history had ASB prevalence of 41.9%. However, participants who had been with diabetes for more than 20 years had the least prevalence of ASB (6.4%).
Antimicrobial sensitivity pattern of diabetic participants: The antimicrobial sensitivity pattern of the isolates from diabetic participants with ASB is shown in Table 5. E. coli, the predominant isolate was most sensitive to GEN and NIT (37.5%) and least sensitive to PPA (6.2%). K. pneumoniae the second most common isolate was 42.8% sensitive to NAL, NIT and GEN and least sensitive to PPA and AMP (33.3%). P. aeroginosa, S. aureus, E. faecalis C. freundi and coagulase negative staphylococcus (CoNS) showed 100% sensitivity to NAL, NIT and GEN.
Historically, Diabetes mellitus has been considered as a risk factor for UTI.
Most cases of UTIs are asymptomatic. Furthermore, complications of UTI mostly
associated with diabetics (Adeyeba et al., 2007
). In this study we sought to establish the prevalence of ASB and also the antimicrobial
sensitivity pattern of the isolated organisms as well as the factors that promote
ASB in T2DM in the Sekondi-takoradi metropolis. We achieved this by undertaking
urine microscopy, culture and AST, measuring BMI and recording patients
history. The prevalence of ASB in this study was 26.4% and E. coli was
the most prominent organism.
The 26.4% prevalence observed in this study is lower than the 31.7% reported
by Makuyana et al. (2002) but comparable to
the 26, 26.6% recorded by Geerlings et al. (2000)
and Alebiosu et al. (2003), respectively. In
contrast however, a lower prevalence (value) has been reported in other studies
(Odetoyin et al., 2008). These percentages are
the ones generally reported among female diabetic patients. Furthermore, geographical
considerations and the fact that only one urine sample was used compared to
the two consecutive samples used in the other studies could account for the
A number of studies have reported a linkage between the duration of diabetes
and ASB (Zhanel et al., 1995; Geerlings
et al., 2000; Mendoza et al., 2002;
Lindsay and Nicolle, 2004). This relationship was confirmed
by observations made in our study; furthermore, we established that ASB was
more prevalent among participants with diabetes duration of 5-10 years. In this
study, the peak incidence of ASB was found in the fifth decade of life for both
the female diabetic participants and the total diabetic population. Furthermore,
ASB was more prevalent in the males in the sixth to eight decade of life. This
supports other studies where UTI was found more commonly in the elderly (Hooton
et al., 2004; Lindsay and Nicolle, 2004). Additionally,
our findings suggested no significant relationship existed between ASB and glycaemic
control in among our population (OR = 1.116) (Table 3), which
is consistent with the findings of Odetoyin et al.
(2008) and Makuyana et al. (2002) but contrary
to the findings of Geerlings et al. (2000),
Ishay et al. (2006) and Boroumand
et al. (2006) who used HBA1c as a measure of glycaemic control.
A number of studies exploring the relationship between ASB and BMI among diabetics
and non-diabetics have opined that no significant difference exists in BMI between
the two groups (Geerlings et al., 2000; Ishay
et al., 2006). Observations made in this study however contradict
these reports. Ghanaian diet is predominantly carbohydrates in nature The predominantly
carbohydrate diet of Ghanaians.
The most prominent pathogen isolated in this study was E. coli (15.6%)
(Table 4). This is in contrast to the findings of Alebiosu
et al. (2003) where K. pneumoniae was the most frequent isolate
from diabetics with ASB. However, this observation is in agreement with the
majority of reports where E. coli had been found to be the major pathogen
in ASB (Olaitan, 2006; Baqai
et al., 2008; Hajeri, 2008; Assel
et al., 2009). E. coli is known to be the commonest cause of
community Acquired Urinary Tract Infections (UTI).
Multiple drug resistance involving AMP, COT, TET, is a common occurrence in
diabetics with UTI as reported by a number of studies (Alebiosu
et al., 2003; Odetoyin et al., 2008).
Findings in our study confirm this observation. These antibiotics could easily
be bought over the counter and that could account for their high resistance
among this group of patients. A study by Tagoe and Attah
(2010) found that the abuse of antibiotics is prevalent in Ghana and that
AMP, COT and TET are among the highly abused drugs (Tagoe
and Attah, 2010).
Most of the isolates from our cultures were susceptible to NAL, NIT and GEN
(Table 5). This is in line with observations made in other
studies (Alebiosu et al., 2003). This implies
that these antibiotics still remain the choice drugs for the treatment of ASB.
ASB is prevalent in 26.4% of the diabetic population in the Sekondi-Takoradi metropolis and E. coli is the most prevalent isolate. Furthermore, factors such as duration of diabetes and advanced age predispose diabetics to ASB even though GEN, NAL and NIT proved the drugs of choice for this diabetic population. It is therefore important for diabetologists to ensure that urine cultures are periodically requested for diabetics even when there are no symptoms. This will serve as a precautionary measure, especially for those at risk.
The authors would like to express their heartfelt appreciation to the clinicians, nurses, biomedical scientists (both at the ENRH laboratory and the Public Health Laboratory) and patients of the diabetic clinic of the ENRH, Takoradi for their immense contributions in making this work a success.
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